Use of a tungsten copper sulfur cluster as a radical trap in trapping aryl radical anions

Abstract

The application relates to application of a tungsten copper sulfur cluster as a free radical capturing agent in capturing aryl radical anions, the chemical formula of the tungsten copper sulfur cluster is [Tp*WS3Cu3(MeCN)3](BF4)2, Tp* is tris (3, 5-dimethyl pyrazole) borohydride. The tungsten copper sulfur cluster can be used for stabilizing aryl radical anions generated in a reaction process in a photo-reaction of tetra-aryl borate, and forms a tungsten copper sulfur cluster-aryl radical anion assembly. Compared with a commonly used organic free radical capturing agent TEMPO, the tungsten copper sulfur cluster shows stronger combination capacity, and the crystal of the formed tungsten copper sulfur cluster-aryl radical anion assembly can exist stably in air for more than 3 months, shows excellent stability, and has good application prospects in photoelectric semiconductor model systems, molecular spin materials, electrochemical redox mediators and photo-reaction mechanism probes.

Description

Technical Field

[0001] This invention relates to the field of free radical scavengers and organic photoreaction chemistry, specifically to the use of a tungsten-copper-sulfur cluster as a free radical scavenger in capturing aryl free radical anions, particularly its application in capturing and stabilizing aryl free radical anion intermediates in a tetraarylborate photoreaction system. Background Technology

[0002] Radical reactions are one of the most important types of chemical reactions in modern materials science and organic synthetic chemistry, widely used in synthetic pathways such as radical coupling, redox transformation, C–C and C–X bond construction, and functional group transformation. Radical species typically include hydroxyl radicals, alkyl radicals, aryl radicals, and borate-derived radical anions. These reactive intermediates play crucial roles in photochemical reactions, photoredox reactions, and photocatalytic cross-coupling reactions (see: DA Nicewicz, DWC MacMillan, Science 2008, 322, 77−80). However, direct observation of the actual radical species formed in the initial stage of the reaction, the transient state of radical anions, and their bond-breaking processes remains a major challenge in current chemical research. This, to some extent, limits a deeper understanding of the photoreaction mechanism and the design of reaction control strategies.

[0003] In existing organic reactions, commercially available free radical scavengers are mainly divided into two categories: organic free radical scavengers and inorganic scavengers. Organic free radical scavengers include 2,2,6,6-tetramethylpiperidine oxide (TEMPO) and 5-tert-butoxycarbonyl-5-methyl-1-pyrrolline N-oxide (BMPO) (see: A. Studer, DP Curran, Angew. Chem. Int. Ed. 2016, 55, 58−102), as well as some inorganic scavengers (see: K. Michalec et al., J. Phys. Chem. C 2024, 128, 5011−5029). These reagents indirectly infer reaction intermediates by forming relatively stable adducts with free radical species, but their scavenging efficiency, specificity, and provision of direct electronic structure information for intermediate free radical species remain limited.

[0004] In photoreaction systems represented by tetraarylborates (such as NaBPh4), although numerous studies have analyzed the product distribution and final-state intermediates of their photodecomposition products (see: K.-H. Tang et al., Angew. Chem.Int. Ed. 2025, 64, e202510095), effective methods for direct observation and efficient capture of the transient bond-breaking process in the early stage of the reaction, the true aryl radical anion structure, and its electronic characteristics are still lacking. Currently, there are no reported rapid, efficient, in-situ capture methods for the true aryl radical anion intermediates in specific photoreactions (such as the photoreaction of tetraarylborates).

[0005] Therefore, there is an urgent need to develop a capture method that can achieve real-time and efficient capture of photoinduced aryl radical anion intermediates and provide their electronic structure information. This method has important scientific research value and potential application prospects for deciphering the mechanism of organic photoreaction, controlling reaction selectivity, and optimizing photoreaction pathways. Summary of the Invention

[0006] Currently, there is no method for rapid, efficient, and in-situ capture of real free radical anion intermediates in the photoreaction of tetraarylborates. To address this issue, this invention provides an application of tungsten-copper-sulfur clusters as free radical scavengers in capturing aryl free radical anions. These tungsten-copper-sulfur clusters can rapidly and efficiently capture highly reactive and short-lived aryl free radical anions (e.g., Ph) in the photoreaction system of tetraarylborates (e.g., NaBPh4). •- ), forming stable free radical anion-binding products (e.g., [(Tp*WS3Cu3)2(Ph)). • )3] + It also identified the negative ion properties of aryl radicals and showed that they maintained excellent stability under air, strong light and high temperature conditions.

[0007] Specifically, the following technical solutions are provided: The first aspect of this invention provides the application of tungsten copper-sulfur clusters as free radical scavengers in capturing aryl free radical anions, wherein the chemical formula of the tungsten copper-sulfur clusters is [Tp*WS3Cu3(MeCN)3](BF4)2, and Tp* is tris(3,5-dimethylpyrazole)hydroborate.

[0008] Further, the tungsten-copper-sulfur clusters are prepared by the following method: [Et4N][Tp*WS3] and [Cu(MeCN)4]BF4 are reacted in the presence of a solvent, centrifuged, filtered to obtain a supernatant, and anhydrous diethyl ether is added to precipitate a solid, thus obtaining the tungsten-copper-sulfur clusters. In some preferred embodiments, the molar ratio of [Et4N][Tp*WS3] to [Cu(MeCN)4]BF4 is 1:3, the solvent is acetone, and the reaction time is 2-4 h.

[0009] Furthermore, the tungsten-copper-sulfur cluster acts as a free radical scavenger to capture the aryl radical anion R generated during the photoreaction of the tetraarylborate shown in formula (I). •- , forming [(Tp*WS3Cu3)2(R • )3] + , where R •- It is an aryl radical anion, wherein the aryl radical anion is a phenyl radical anion or a 4-halogen-substituted phenyl radical anion; the structure of formula (I) is as follows: R' is H, F or Cl, and M is sodium or potassium.

[0010] Preferably, the molar ratio of the tungsten copper sulfur cluster to the tetraaryl borate is 1:(2-5), for example, 1:2, 1:3, 1:4, 1:5, etc., including but not limited to the molar ratios listed above.

[0011] Preferably, the photoreaction is carried out in the presence of a solvent, including but not limited to acetone, wherein the molar ratio of the tetraarylborate to the volume of the solvent is 1 mmol: (50-100) mL.

[0012] Preferably, the photoreaction is carried out at 10-40 °C (e.g., room temperature) under natural light conditions.

[0013] Furthermore, after the photoreaction is complete, the mixture containing [(Tp*WS3Cu3)2(R) will be... • )3] + The reaction system is placed in a closed container containing a diffusion solvent, and gas-liquid diffusion is carried out to precipitate crystals, resulting in crystals containing aryl radical anions; in some preferred embodiments, the diffusion solvent is a mixture of diethyl ether and benzene or toluene.

[0014] A second aspect of the present invention provides a tungsten-copper-sulfur cluster-aryl radical anionic assembly, wherein the tungsten-copper-sulfur cluster-aryl radical anionic assembly comprises [(Tp*WS3Cu3)2(R • )3] + R •-It is a phenyl radical anion or a 4-halogen-substituted phenyl radical anion, wherein R • This indicates a phenyl radical or a 4-halogen-substituted phenyl radical.

[0015] Furthermore, the tungsten-copper-sulfur cluster-aryl radical anionic assembly is a crystal with the chemical formula [(Tp*WS3Cu3)2(R • )3]BX4·nA, where X is F or a 4-halogen-substituted phenyl group, n is 1 or 2, and A is selected from one or more of diethyl ether, isopropyl ether, toluene, benzene, xylene, acetone, chloroform, dichloromethane, and tetrahydrofuran.

[0016] Furthermore, when the chemical formula of the tungsten-copper-sulfur cluster-aryl radical anionic assembly is [(Tp*WS3Cu3)2(Ph • When )3]BF4·PhMe, Ph is phenyl, and the tungsten-copper-sulfur cluster-aryl radical anionic assembly crystallizes in a monoclinic crystal system with space group . P twenty one / c The unit cell parameters are: a = 15.1292(9) Å, b = 28.9554(16) Å, c = 15.1380(8) Å, α = 90°, β = 99.380(2)°, γ = 90°, V = 6542.9(6) Å. 3 .

[0017] Furthermore, when the chemical formula of the tungsten-copper-sulfur cluster-aryl radical anionic assembly is [(Tp*WS3Cu3)2( F Ph • )3]B F When Ph4·CHCl3·Et2O, F Ph represents 4-fluorophenyl, and the tungsten-copper-sulfur cluster-aryl radical anionic assembly crystallizes in a monoclinic system with space group [space group missing]. P twenty one / n The unit cell parameters are: a = 13.8905(8) Å, b = 25.3189(16) Å, c = 24.8942(12) Å, α = 90°, β = 98.877(2)°, γ = 90°, V = 8650.2(9) Å. 3 .

[0018] Furthermore, when the chemical formula of the tungsten-copper-sulfur cluster-aryl radical anionic assembly is [(Tp*WS3Cu3)2( Cl Ph • When )3]BF4·2C6H6, Cl Ph represents 4-chlorophenyl, and the tungsten-copper-sulfur cluster-aryl radical anionic assembly is crystallized in an orthorhombic crystal system with space group [space group missing]. CmcmThe unit cell parameters are: a = 22.7582(6) Å, b = 16.4061(6) Å, c = 19.1035(6) Å, α = β = γ = 90°, V = 7132.7(4) Å. 3 .

[0019] A third aspect of this invention provides a method for preparing the tungsten-copper-sulfur cluster-aryl radical anionic assembly described in the second aspect, comprising the following steps: S1. The tungsten copper-sulfur cluster is mixed with an organic solution of tetraarylborate and stirred under light to obtain a product containing [(Tp*WS3Cu3)2(R • )3] + A mixed solution; The chemical formula of the tungsten copper-sulfur cluster is [Tp*WS3Cu3(MeCN)3](BF4)2, where Tp* is tris(3,5-dimethylpyrazole)hydroborate. The structure of the tetraarylborate is as follows: R' is H, F, or Cl, and M is sodium or potassium. S2, the content containing [(Tp*WS3Cu3)2(R • )3] + The mixed solution precipitates crystals through gas-liquid diffusion to obtain the tungsten-copper-sulfur cluster-aryl radical anion assembly.

[0020] Further, in step S1, the organic solution of the tetraarylborate is obtained by dissolving the tetraarylborate in an organic solvent, wherein the organic solvent may be selected from one or more of acetone, chloroform, dichloromethane, and tetrahydrofuran.

[0021] Preferably, the molar ratio of the tungsten copper sulfur cluster to the tetraaryl borate is 1:(2-5), such as 1:2, 1:3, 1:4, 1:5, etc., including but not limited to the molar ratios listed above.

[0022] Preferably, the temperature of the stirring reaction is 10-40 °C and the time is 20-50 min.

[0023] Preferably, the lighting conditions are natural light.

[0024] Further, in step S2, the container containing [(Tp*WS3Cu3)2(R) is... • )3] + The container of the mixed solution is placed in a sealed container containing a diffusion solvent to carry out gas-liquid diffusion, crystals are precipitated, and the tungsten copper sulfur cluster-aryl radical anion assembly is obtained.

[0025] Preferably, the diffusion solvent comprises a first solvent and a second solvent, wherein the first solvent is diethyl ether and / or isopropyl ether, and the second solvent is selected from one or more of toluene, benzene, and xylene; more preferably, the volume ratio of the first solvent to the second solvent is (2-4):1, for example, 3:1.

[0026] Furthermore, the gas-liquid diffusion time is 14-28 days.

[0027] The fourth aspect of this invention provides the application of the tungsten-copper-sulfur cluster-aryl radical anion assembly described in the second aspect or the tungsten-copper-sulfur cluster-aryl radical anion assembly prepared by the preparation method described in the third aspect in the fields of radical storage and regulation, optoelectronic semiconductor model systems, molecular spin materials, electrochemical redox mediators, or photoreaction mechanism probes.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention, for the first time, utilizes the tungsten-copper-sulfur cluster [Tp*WS3Cu3(MeCN)3](BF4)2 as a radical scavenger to capture aryl radical anions generated by the photoreaction of tetraarylborates. By leveraging the multi-metal synergistic structure of the tungsten-copper-sulfur cluster, it directly and efficiently captures aryl radical anions generated in the initial stage of the reaction. Compared to the traditional scavenger TEMPO, it exhibits stronger binding capacity and allows for clear identification of the negative charge properties of the captured aryl radicals through structural characterization and paramagnetic signal analysis, enabling accurate determination of the true electronic state of the aryl radical anions.

[0029] The aforementioned tungsten-copper-sulfur clusters can directly carry out aryl radical anion capture reactions in air and under natural light conditions, without the need for strict oxygen-free or light-protected operating conditions, which significantly reduces the requirements for experimental conditions; moreover, the capture process is rapid and can complete the binding of aryl radical anions and form stable crystalline products in real time, showing excellent reaction kinetic advantages.

[0030] The tungsten-copper-sulfur cluster-aryl radical anion assembly crystal formed by capturing aryl radical anions through tungsten-copper-sulfur clusters can remain stable in air for more than 3 months without significant attenuation of the radical signal, demonstrating excellent stability. This provides a reliable guarantee for subsequent structural characterization, electronic structure analysis, and applications in optoelectronic semiconductor models, molecular spin materials, and other fields.

[0031] Compared with the commonly used organic free radical scavenger TEMPO, the tungsten-copper-sulfur cluster scavenging system provided by this invention has significant advantages in binding capacity, stability and recognition of aryl free radical anion properties, which can provide important technical support and application value for the study of organic photoreaction mechanisms and reaction pathway regulation. Attached Figure Description

[0032] Figure 1 The reaction flowchart for using the tungsten-copper-sulfur cluster A1 prepared in Example 1 to capture aryl radical anions generated by the photoreaction of tetraarylborates is shown. Figure 2 Here is a high-resolution electrospray mass spectrum of the captured product A2 prepared in Example 1 in dichloromethane; Figure 3 The electron paramagnetic resonance spectra of the captured product A2 prepared in Example 1 in crystalline form and dichloromethane solution; Figure 4 Crystal structure diagram of the captured product A2 prepared in Example 1; Figure 5 Here is a high-resolution electrospray mass spectrum of the captured product A3 prepared in Example 2; Figure 6 The electron paramagnetic resonance spectra of the captured product A3 prepared in Example 2 in crystalline form and dichloromethane solution; Figure 7 Crystal structure diagram of the captured product A3 prepared in Example 2; Figure 8 Here is a high-resolution electrospray mass spectrum of the captured product A4 prepared in Example 3; Figure 9 The crystal structure diagram of the captured product A4 prepared in Example 3; Figure 10 The X-ray photoelectron spectra of the captured products A2 and A3 in the crystalline state in Example 4 are shown. Figure 11 The UV spectra and solid UV diffuse reflectance diagrams of the captured products A1, A2, and A3 tested in Example 4 are shown. Figure 12 This is a graph showing the electrochemical performance of the captured product A2 in methanol and water tested in Example 4; Figure 13 The electron paramagnetic resonance spectra of the captured product A2 crystal in Example 5 before and after storage in air and natural light for 3 months. Figure 14 The 1H NMR spectra of the deuterated dichloromethane solution used to test the captured product A2 in Example 5 after storage at room temperature and in air for different times. Figure 15 The high-resolution electrospray mass spectra of the acetone solution used to test the captured product A2 in Example 5 after being stored at room temperature and in air for 3 months and heated at 100 °C for 5 hours are shown. Figure 16 The diagram shows the ability of the tungsten-copper-sulfur cluster A1 to capture phenyl radical anions under different conditions in Examples 6 and 7. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The terms “comprising” or “including” used in this invention may also be replaced with the closed form “is” or “consisting of”. Example 1

[0035] This embodiment relates to the preparation of a tungsten-copper-sulfur cluster and its application as a free radical scavenger in the photoreaction of tetraarylborates to capture aryl radical anions, as detailed below: (1) Preparation of tungsten-copper-sulfur cluster A1: Based on [Et4N][Tp*WS3] (Tp* is tris(3,5-dimethylpyrazole)hydroborate), the metal cluster A1 was synthesized according to the literature (Y.-H. Deng, BF Abrahams, J.-P. Lang, J. Am. Chem. Soc. 2025,147, 18219−18229), with the chemical formula [Tp*WS3Cu3(MeCN)3](BF4)2 (MeCN is acetonitrile). Details are as follows: [Et4N][Tp*WS3] (0.071 g, 0.1 mmol) and [Cu(MeCN)4]BF4 (0.095 g, 0.3 mmol) were weighed at a molar ratio of 1:3 and added to a reaction vessel. Acetone (5 mL) was then added as the reaction solvent, and the mixture was thoroughly mixed. The reaction was stirred at room temperature for 2 hours, during which the solution color gradually changed from reddish-brown to brownish-red. After the reaction was complete, the reaction mixture was centrifuged and filtered. The supernatant was collected, and anhydrous diethyl ether (20 mL) was slowly added to precipitate the product. The precipitate was collected by centrifugation, washed with excess anhydrous diethyl ether, and dried at room temperature to give 0.092 g of brown solid product A1, yield: 86% (based on tungsten).

[0036] The solid product A1 was characterized by proton nuclear magnetic resonance spectroscopy and high-resolution electrospray mass spectrometry. The characterization results are as follows: 1H NMR spectrum (400 MHz, deuterated acetone, 298 K): δ = 6.21 (s, 6H), 2.89 (s, 9H), 2.48 (s, 9H), 2.13 (s, 42H) ppm.

[0037] High-resolution electrospray spectroscopy (solution, dichloromethane): {[Tp*WS3Cu3(MeCN)2] 2+ +BF4 –} + C 19 H 28 N8B2S3F4WCu3, theoretical value: 936.9109, experimental value: 936.9035.

[0038] Therefore, this embodiment successfully prepared the tungsten copper-sulfur cluster [Tp*WS3Cu3(MeCN)3](BF4)2.

[0039] (2) The tungsten-copper-sulfur cluster A1 prepared in step (1) was used to capture the phenyl radical anions generated by the photoreaction of sodium tetraphenylborate, as follows: Preparation of the captured product: Sodium tetraphenylborate NaBPh4 (0.034 g, 0.1 mmol) and metal cluster A1 (0.212 g, 0.2 mmol) were taken at a molar ratio of 1:2 under ambient light and in the dark. Acetone (6 mL) was added as the reaction solvent under ambient light. The reaction vessel was then placed under natural light and stirred for 20 minutes. The color of the reaction solution gradually changed from brownish-red to blackish-red. After the reaction was completed, the reaction solution was centrifuged, and the supernatant was added to a glass tube. The tube was then placed in a glass bottle (500 mL) containing a mixture of anhydrous diethyl ether and toluene (30 mL, volume ratio 3 / 1). The bottle was capped and placed in a dark and dry environment for gas-liquid diffusion. After 14 days, blackish-red crystals were obtained. The crystals were filtered and washed with anhydrous diethyl ether and dried under vacuum to obtain 0.159 g of the captured product, tungsten copper-sulfur cluster-phenyl radical anion assembly A2, with a yield of 82% (based on tungsten).

[0040] The captured product A2 was characterized by proton nuclear magnetic resonance spectroscopy, high-resolution electrospray mass spectrometry, electron paramagnetic resonance spectroscopy, and single-crystal diffraction. The characterization results are as follows: 1H NMR spectrum (400 MHz, CD₂Cl₂, 298 K): δ = 9.12–9.10 (d, J) H–H = 6.4 Hz,6H), 7.83–7.80 (t, J H–H = 7.2 Hz, 3H), 7.58–7.54 (t, J H–H = 7.6 Hz, 6H), 5.74(s, 6H), 2.28 (s, 18H), 1.51 (s, 18H) ppm.

[0041] High-resolution electrospray mass spectrometry (solution, dichloromethane): such as Figure 2 As shown, {[(Tp*WS3Cu3)2(Ph• )3]} + C 48 H 59 N 12 B2S6W2Cu6, theoretical value: 1766.8272, experimental value: 1766.8256. This further confirms the uniqueness and integrity of the structure of the captured product A2.

[0042] Electron paramagnetic resonance (continuous wave, X-band, single crystal, 298 K): such as Figure 3 As shown, g1 = 2.056, g2 = 2.232, and g3 = 2.349, consistent with the values ​​of the metal-centered radical. In dichloromethane solution, the captured product A2 exhibits an isotropic signal at g = 2.174, indicating the continued existence of the radical state.

[0043] Single crystal diffraction: The crystal structure of the captured product is as follows Figure 4 As shown, the crystallographic parameters are given in Table 1 below, and its chemical formula is [(Tp*WS3Cu3)2(Ph • )3]BF4·PhMe. In P twenty one / c Crystallized within the space group, two [Tp*WS3Cu3] 2+ Stabilized three phenyl radical anions (Ph •– ), and has a BF4 – A counterion and a co-crystallized toluene PhMe molecule. Three Ph •– The linker connects the upper and lower [WCu3] clusters via Cu–C bonds (1.996–2.040 Å), which are approximately 0.13 Å shorter than the bond lengths in copper cluster compounds composed of traditional phenyl anions and Cu(I) clusters. Simultaneously, the Cu···Cu distance between the upper and lower clusters is increased to 2.552–2.574 Å, significantly shorter than the S… 2– The bridging Cu···Cu distance (2.901 Å) highlights the stronger structural driving force of the phenyl radical anion. Six copper ions assemble into a highly symmetrical [Cu6] trigonal prism core, externally formed by [Tp*WS3]. – Skeleton and three Ph •– The linkers exhibit synergistic stability. Furthermore, the three phenyl radical anions form an equatorial plane, with each unit generating a [Cu₂C] triangular framework oriented almost perpendicular to the benzene ring (dihedral angle 87.4°–89.1°). One unit has a Cu–C–Cu angle of 79.04°, while the other two base angles are more acute (50.14° and 50.94°), approximating an isosceles triangular geometry. These structural advantages provide a structural basis for stabilizing phenyl radical anions under extreme conditions.

[0044] Therefore, this embodiment successfully obtained the captured product A2 by stabilizing the phenyl radical anion through the tungsten-copper-sulfur cluster A1.

[0045] Table 1 Crystallographic parameters of captured product A2

[0046] Example 2 This embodiment involves using tungsten-copper-sulfur clusters A1 as free radical scavengers in sodium tetrafluorophenylborate (NaB). F The application of Ph4 in the capture of p-fluorophenyl radical anions differs from Example 1 only in that 0.1 mmol NaBPh4 is replaced with 0.1 mmol NaB F Ph4 (0.041 g), and 1 mL of chloroform was added to the separated supernatant to obtain better quality crystals, and the rest of the operation was the same, to obtain 0.187 g of the captured product tungsten copper sulfur cluster-fluorophenyl radical anion assembly A3, yield: 78% (based on tungsten).

[0047] The captured product A3 was characterized by proton nuclear magnetic resonance spectroscopy, high-resolution electrospray mass spectrometry, electron paramagnetic resonance spectroscopy, and single-crystal diffraction. The characterization results are as follows: 1H NMR spectrum (400 MHz, CD₂Cl₂, 298 K): δ = 9.19–8.97 (m, 6H), 7.33–7.28 (t, J) H–H = 8.8 Hz, 6H), 5.77 (s, 6H), 2.32 (s, 18H), 2.13–1.54 (s, 18H) ppm.

[0048] High-resolution electrospray mass spectrometry (solution, dichloromethane): such as Figure 5 As shown, {[(Tp*WS3Cu3)2( F Ph • )3]} + C 48 H 56 N 12 B2S6F3W2Cu6, theoretical value: 1820.7990, experimental value: 1820.8083, indicating that the captured product A3 has good structural stability in solution.

[0049] Electron paramagnetic resonance (continuous wave, X-band, single crystal, 298 K): such as Figure 6 As shown, g = 2.193. Furthermore, the figure indicates that the captured product A3 exists as a free radical species in both the crystalline and solution states.

[0050] Single crystal diffraction: The crystal structure of the captured product is as follows Figure 7 As shown, the crystallographic parameters are given in Table 2 below, and its chemical formula is [(Tp*WS3Cu3)2( F Ph • )3]B F Ph4·CHCl3·Et2O. In P twenty one / n Crystallized within the space group, two [Tp*WS3Cu3] 2+ Stabilized three fluorophenyl radical anions ( F Ph •– Its molecular skeleton is a triangular prism [Cu6] core, with three F Ph •– They are coplanarly distributed at the equator and have the same structure as the captured product A2.

[0051] Therefore, this embodiment successfully stabilized the p-fluorophenyl radical anion with the tungsten-copper-sulfur cluster A1 to obtain the captured product A3, which further demonstrates the effectiveness and universality of the tungsten-copper-sulfur cluster A1 as a novel radical scavenger in capturing aryl radical anions in photoreaction.

[0052] Table 2 Crystallographic parameters of captured product A3

[0053] Example 3 This embodiment relates to the application of tungsten-copper-sulfur cluster A1 as a free radical scavenger in the photoreaction of potassium tetrachlorophenylborate to capture p-chlorophenyl radical anions. The only difference from Example 1 is that 0.1 mmol NaBPh4 is replaced with 0.1 mmol KB. Cl Ph4 (0.049 g); In the gas-liquid diffusion step, toluene was replaced with an equal amount of benzene, and the rest of the operation was the same, to obtain 0.154 g of the captured product tungsten-copper-sulfur cluster-chlorophenyl radical anion assembly A4, with a yield of 73%.

[0054] The captured product A4 was characterized by high-resolution electrospray mass spectrometry and single-crystal diffraction. The characterization results are as follows: High-resolution electrospray mass spectrometry test results are as follows Figure 8 As shown: In m / z A strong mass spectrum signal peak was observed at 1870.7034, which is attributed to {[(Tp*WS3Cu3)2( Cl Ph • )3]} + The molecular fragments, consistent with the chemical composition of A2 and A3, indicate structural uniformity, and the formation of product A4 was identified by high-resolution electrospray mass spectrometry.

[0055] Single crystal diffraction: The crystal structure of the captured product is as follows Figure 9As shown, the crystallographic parameters are given in Table 3 below, and its chemical formula is [(Tp*WS3Cu3)2( Cl Ph • )3]BF4·2C6H6. In Cmcm Crystallized within the space group, two [Tp*WS3Cu3] 2+ Stabilized three chlorophenyl radical anions ( Cl Ph •– Its molecular skeleton is a triangular prism [Cu6] core, with three Cl Ph •– They are coplanarly distributed at the equator and have the same structure as the captured product A2.

[0056] Table 3 Crystallographic parameters of captured product A4

[0057] Example 4 This embodiment further investigates the photoelectric properties of the tungsten-copper-sulfur cluster A1 and the capture products A2 and A3 prepared in Examples 1 and 2, as detailed below: X-ray photoelectron spectroscopy confirmed the stability of the valence state of trapped metallic copper, such as... Figure 10 As shown, the results indicate that the Cu 2p orbital binding energies of the tungsten copper-sulfur cluster A1 are consistent with those of the captured products A2 and A3, suggesting that the copper center is still in the Cu(I) valence state.

[0058] Figure 11 The UV spectra and solid-state UV diffuse reflectance spectra of the tungsten-copper-sulfur cluster A1 and its capture products A2 and A3 are shown. As can be seen, the tungsten-copper-sulfur cluster A1 exhibits absorption at 326 nm and 514 nm, while the capture product A2 shows strong absorption bands at 229 nm and 347 nm, with an absorption range of 200 nm–700 nm. Diffuse reflectance measurements indicate that the indirect bandgap of A1 is 2.76 eV, while the capture products A2 and A3 both possess relatively wide bandgap values ​​of 3.83 eV and 3.70 eV, respectively. These values ​​place A2 and A3 within the range of wide bandgap semiconductors, comparable to UV-active photocatalytic systems, highlighting their potential as cluster-based photoelectric and photochemical modeling platforms.

[0059] Electrochemical performance studies were conducted in [Et4N]BF4 electrolyte. The specific procedures were as follows: The test compound A2 was mixed with conductive carbon black at a mass ratio of 5:5 and ground into a uniform fine powder in an agate mortar. The mixed powder was transferred to a small glass bottle (2 mL), and isopropanol (925 μL) and Nafion solution (75 μL) were added sequentially. The mixture was ultrasonically dispersed for 30 minutes to obtain a uniformly dispersed suspension. 20 μL of this suspension was uniformly drop-coated onto the surface of a pretreated glassy carbon electrode and dried under an infrared lamp to obtain the working electrode. A standard three-electrode system was used for testing, with the working electrode prepared above as the working electrode, an Ag / AgCl electrode as the reference electrode, and a graphite electrode as the counter electrode. The electrolyte was a 0.1 M tetraethylammonium tetrafluoroborate ([Et4N]BF4) solution, with methanol and water used as solvents to prepare two different electrolyte solutions. During testing, the potential window of the electrochemical workstation was set to -3 V to 3 V (vs. Ag / AgCl), and the scan rate was 100 mV·s. –1 The circuit is scanned 10 times and the cyclic voltammetry curve is recorded.

[0060] Figure 12 The captured product A2 in MeOH showed a reduction peak at -1.63 V for the Cu or W centers, a second reduction at -2.78 V for the phenyl radical anion, and quasi-reversible oxidation at approximately 2.41 V. In H2O, only a weak reduction at -0.94 V and a significant oxidation at 1.19 V were observed. These electrochemical results indicate that the captured product A2 possesses good redox properties. Example 5

[0061] This embodiment further investigates the structural stability of the capture product formed by the tungsten-copper-sulfur cluster A1 capturing aryl radical anions. Taking the capture product A2 as an example, the specific operation is as follows: Crystal stability test: The captured product A2 crystal was stored in air and natural light for 3 months, and then electron paramagnetic resonance (EPR) testing was performed. The test results are as follows: Figure 13 As shown, electron paramagnetic resonance spectroscopy reveals that the captured product A2 still exists in the form of a free radical species, and the signal is enhanced by 17 times.

[0062] Solution stability test: The captured product A2 crystals were dissolved in acetone and stored at room temperature and in air. Samples were taken after 1 month and 3 months of storage for 1H NMR characterization. The results are as follows: Figure 14 As shown, the results exhibit stable hydrogen peak splitting and characteristic peak signals; additionally, high-resolution electrospray mass spectrometry (HS-MS) analysis was performed on the solution after 3 months of storage, and the results are as follows. Figure 14 As shown, only the A2 molecular component exists.

[0063] High-temperature stability test: The captured product A2 crystals were dissolved in acetone, then heated under reflux at 100 °C for 5 hours. Samples were then taken for high-resolution electrospray mass spectrometry (HPLC-MS / MS) analysis. The test results are as follows: Figure 15 As shown, only the A2 molecular component exists.

[0064] This shows that the captured product can maintain good structural stability when placed in air for a long time and at high temperature, which also indicates that the tungsten copper sulfur cluster A1 can overcome the damage and interference of long time and high temperature to the stability of aryl radical anions. Example 6

[0065] This embodiment further investigates the ability of the tungsten-copper-sulfur cluster A1 to capture aryl radical anions, using the traditional scavenger TEMPO as a competitive scavenger. The specific operation is as follows: NaBPh4 (0.004 g, 0.01 mmol), TEMPO (0.003 g, 0.02 mmol), and tungsten-copper-sulfur cluster A1 (0.021 g, 0.02 mmol) were weighed in air and added to the reaction vessel. Acetone (3 mL) was added to the mixture under light-protected conditions to ensure complete dissolution and homogenization. The reaction system was then placed under natural light and stirred at room temperature for 20 minutes. After the reaction was complete, the reaction solution was centrifuged, and the supernatant was transferred to a glass tube. The glass tube was placed in a sealed glass bottle (500 mL) containing anhydrous diethyl ether and benzene (10 mL, 3 / 1 volume ratio), and crystallization was carried out using gas-liquid diffusion. After standing for 14 days, crystals precipitated, and the crystals were collected and characterized by single-crystal X-ray diffraction.

[0066] The results are as follows Figure 16 As shown, the obtained crystal is the crystal of the captured product A2. It can be seen that the tungsten copper sulfur cluster A1 has a stronger binding ability to aryl radical anions than TEMPO. Example 7

[0067] This embodiment further investigates the ability of the tungsten-copper-sulfur cluster A1 to capture aryl radical anions under extreme conditions. The specific operation is as follows: NaBPh4 (0.004 g, 0.01 mmol) and tungsten copper-sulfur cluster A1 (0.021 g, 0.02 mmol) were weighed in air and added to a reaction vessel. Acetone (3 mL) was added to the mixture under light-protected conditions to ensure complete dissolution and homogenization. Two identical reaction samples were prepared; one was irradiated under sunlight for 4 hours, and the other under a 365 nm UV lamp for 4 hours. All other procedures were the same as in Example 1. Experimental results showed that both methods successfully captured phenyl radical anions to form the captured product A2.

[0068] The above experimental results show that the tungsten-copper-sulfur cluster A1 has a strong capture specificity and environmental tolerance for aryl radical anions. It can be used as an aryl radical anion scavenger to address the challenges of controlling organic reaction products and studying mechanisms, such as the low lifetime of free radicals, the low stability of intermediates, and special reaction scenarios.

[0069] The embodiments described above are merely preferred examples to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. The application of a tungsten-copper-sulfur cluster as a free radical scavenger in capturing aryl radical anions, characterized in that, The chemical formula of the tungsten-copper-sulfur cluster is [Tp*WS3Cu3(MeCN)3](BF4)2, where Tp* is tris(3,5-dimethylpyrazole)hydroborate.

2. The application according to claim 1, characterized in that, The tungsten-copper-sulfur clusters are used as free radical scavengers to capture the aryl radical anions R generated during the photoreaction of the tetraarylborate shown in formula (I). •− , forming [(Tp*WS3Cu3)2(R • )3] + , where R •– It is an aryl radical anion, wherein the aryl radical anion is a phenyl radical anion or a 4-halogen-substituted phenyl radical anion; The structure of equation (I) is as follows: R' is H, F or Cl, and M is sodium or potassium.

3. A tungsten-copper-sulfur cluster-aryl radical anionic assembly, characterized in that, The tungsten-copper-sulfur cluster-aryl radical anion assembly contains [(Tp*WS3Cu3)2(R • )3] + R •– It is a phenyl radical anion or a 4-halogen-substituted phenyl radical anion.

4. The tungsten-copper-sulfur cluster-aryl radical anionic assembly according to claim 3, characterized in that, The tungsten-copper-sulfur cluster-aryl radical anionic assembly is a crystal with the chemical formula [(Tp*WS3Cu3)2(R • )3]BX4·nA, where, X is F or a 4-halogen-substituted phenyl, n is 1 or 2, and A is selected from one or more of diethyl ether, isopropyl ether, toluene, benzene, xylene, acetone, chloroform, dichloromethane, and tetrahydrofuran.

5. The tungsten-copper-sulfur cluster-aryl radical anionic assembly according to claim 4, characterized in that, When the chemical formula of the tungsten copper sulfur cluster-aryl radical anion assembly is [(Tp*WS3Cu3)2(Ph • When )3]BF4·PhMe, Ph represents phenyl, and the tungsten-copper-sulfur cluster-aryl radical anionic assembly crystallizes in a monoclinic crystal system with space group . P twenty one / c The unit cell parameters are: a = 15.1292(9) Å, b = 28.9554(16) Å, c = 15.1380(8) Å, α = 90°, β = 99.380(2)°, γ = 90°, V = 6542.9(6) Å. 3 ; When the chemical formula of the tungsten copper sulfur cluster-aryl radical anion assembly is [(Tp*WS3Cu3)2( F Ph • )3]B F When Ph4·CHCl3·Et2O, F Ph represents 4-fluorophenyl, and the tungsten-copper-sulfur cluster-aryl radical anionic assembly crystallizes in a monoclinic system with space group [space group missing]. P twenty one / n The unit cell parameters are: a = 13.8905(8) Å, b = 25.3189(16) Å, c = 24.8942(12) Å, α = 90°, β = 98.877(2)°, γ = 90°, V = 8650.2(9) Å. 3 ; When the chemical formula of the tungsten copper sulfur cluster-aryl radical anion assembly is [(Tp*WS3Cu3)2( Cl Ph • When )3]BF4·2C6H6, Cl Ph represents 4-chlorophenyl, and the tungsten-copper-sulfur cluster-aryl radical anionic assembly is crystallized in an orthorhombic crystal system with space group [space group missing]. Cmcm The unit cell parameters are: a = 22.7582(6) Å, b = 16.4061(6) Å, c = 19.1035(6) Å, α = β = γ = 90°, V = 7132.7(4) Å. 3 .

6. A method for preparing a tungsten-copper-sulfur cluster-aryl radical anionic assembly, characterized in that, Includes the following steps: S1. The tungsten copper-sulfur cluster is mixed with an organic solution of tetraarylborate and stirred under light to obtain a product containing [(Tp*WS3Cu3)2(R • )3] + A mixed solution; The chemical formula of the tungsten copper-sulfur cluster is [Tp*WS3Cu3(MeCN)3](BF4)2, where Tp* is tris(3,5-dimethylpyrazole)hydroborate. The structure of the tetraarylborate is as follows: R' is H, F or Cl, and M is sodium or potassium; S2, the content containing [(Tp*WS3Cu3)2(R • )3] + The mixed solution precipitates crystals through gas-liquid diffusion to obtain the tungsten-copper-sulfur cluster-aryl radical anion assembly.

7. The preparation method according to claim 6, characterized in that, In step S1, the organic solution of the tetraarylborate is obtained by dissolving the tetraarylborate in an organic solvent, wherein the organic solvent is selected from one or more of acetone, chloroform, dichloromethane, and tetrahydrofuran; And / or, the molar ratio of the tungsten copper sulfur cluster to the tetraaryl borate is 1:(2-5). And / or, the temperature of the stirring reaction is 10-40 °C and the time is 20-50 min.

8. The preparation method according to claim 6, characterized in that, In step S2, the container containing [(Tp*WS3Cu3)2(R) is... • )3] + The container of the mixed solution is placed in a closed container containing a diffusion solvent to carry out gas-liquid diffusion, crystals are precipitated, and the tungsten copper sulfur cluster-aryl radical anion assembly is obtained. The diffusion solvent comprises a first solvent and a second solvent, wherein the first solvent is diethyl ether and / or isopropyl ether, and the second solvent is selected from one or more of toluene, benzene, and xylene.

9. The preparation method according to claim 8, characterized in that, In step S2, the volume ratio of the first solvent to the second solvent is (2-4):1; And / or, the gas-liquid diffusion time is 14-28 days.

10. The application of the tungsten-copper-sulfur cluster-aryl radical anion assembly according to any one of claims 3-5 or the tungsten-copper-sulfur cluster-aryl radical anion assembly prepared by the preparation method according to any one of claims 6-9 in the fields of radical storage and regulation, optoelectronic semiconductor model system, molecular spin material, electrochemical redox mediator or photoreaction mechanism probe.

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