Monodentate thiol group and nitrosoaromatic hydrocarbon bridged binuclear cobalt complex, preparation method and application thereof

Abstract

This invention belongs to the technical field of nitrosoarene preparation. Disclosed are binuclear cobalt complexes bridged by a monodentate thiol group and a nitrosoarene, their preparation methods, and applications. The binuclear cobalt complex has the structure of Formula I, wherein the monodentate thiol group and the nitrosoarene serve as bridging groups, and each cobalt atom is coordinated with a cyclopentadiene ligand, a substituted cyclopentadiene ligand, an indene ligand, or a fluorene ligand. The binuclear cobalt complex provided by this invention can catalyze the reduction of nitrosoarene compounds to aromatic amines in the presence of borane. The reaction temperature is between -20°C and 50°C, and the reaction time is between 2 and 48 hours. #imgabs0#

Description

Technical Field

[0001] The present invention belongs to the technical field of nitrosoarene preparation, relates to a binuclear cobalt complex bridged by a monodentate thiol group and a nitrosoarene, a preparation method and application thereof, and particularly relates to an application thereof in the catalytic reduction of nitrosoarene to aromatic amines. Background Art

[0002] Nitrosoarenes (ArNO) have extensive applications in modern synthetic chemistry and materials science, serving as common reaction substrates in organic synthesis, as spin traps in electron spin resonance spectroscopy, and as building blocks for covalent organic networks. Furthermore, since nitrosoarenes are biologically active metabolites of nitroarenes and arylamines, studying the activation and transformation of nitrosoarenes mediated by transition metal centers is of great significance for understanding the metabolic processes of nitroarenes and arylamines in vivo. Furthermore, the interactions between nitrosoarenes and transition metals have attracted widespread attention due to their biological relevance. For example, nitrosoarenes can act as isoelectronic partners for oxygen, and transition metal nitrosoarene complexes are often considered mimics of transition metal oxygen adducts. Compared to mononuclear complexes, binuclear transition metal complexes often achieve more efficient activation and transformation of nitrosoarenes. However, due to the difficulty of their construction and complex structure, reports on binuclear transition metal nitrosoarene complexes are relatively limited.

[0003] The reported binuclear transition metal nitrosoarene complexes mainly include: diiron complexes (J.Am.Chem.Soc.2021,143,17374), dicopper complexes (J.Am.Chem.Soc.2020,142,19023; Inorg.Chem.2020,59,8678; Chem.Commun.2015,51,11206), and dinickel complexes (J.Am.Chem.Soc.2009,131,18105). Summary of the Invention

[0004] The present invention aims to provide a binuclear cobalt complex bridged by a monodentate thiol group and a nitrosoarene, a preparation method thereof, and an application thereof in catalyzing the reduction of nitrosoarene compounds to aromatic amines.

[0005] The technical solutions of the present invention are as follows:

[0006] A monodentate thiol- and nitrosoarene-bridged dinuclear cobalt complex with the following structure:

[0007]

[0008] In the general structural formula Ⅰ:

[0009] R 1Selected from adamantyl (Ad) or ethyl (Et);

[0010] R 2 Any one selected from the group consisting of cyclopentadiene ligands, monomethylcyclopentadiene ligands, dimethylcyclopentadiene ligands, trimethylcyclopentadiene ligands, tetramethylcyclopentadiene ligands, pentamethylcyclopentadiene ligands, 1,2,4-tri-tert-butylcyclopentadiene ligands, indene ligands, and fluorene ligands;

[0011] Ar is selected from phenyl and its derivatives, and the hydrogen atoms on the benzene ring may be substituted by amino, nitro or halogen;

[0012] X - To resist negative ions, selected from PF6 - 、SbF6 - 、BF4 - , BPh4 - CF3SO3 - 、B(C6F5)4 - and B(3,5-(CF3)2C6H3)4 - Any of the following;

[0013] n is 0, 1, or 2;

[0014] m is 1 or 2;

[0015] k is 0 or 1.

[0016] According to the above description, the specific complex structures are listed as shown in Table 1, where: Ad, Cp, Cp 1 、Cp 2 、Cp 3 、Cp 4 , Cp*, Cp', Ind, Flu represent the following structures:

[0017] Table 1 Specific structures of monodentate thiol- and nitrosoarene-bridged binuclear cobalt complexes

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028] In the preferred embodiment of the present invention, R 1 =Ad or Et.

[0029] In another preferred embodiment, R 2 =Cp* or Cp'.

[0030] In another preferred embodiment, Ar=Ph.

[0031] In another preferred embodiment, X - =PF6 - or BPh4 - .

[0032] More preferably, the complex of the present invention is selected from:

[0033] Complex 1: R 1 =Et, R 2 =Cp*, Ar=Ph, n=1, m=2, k=0, X - =PF6 - ;

[0034] Complex 2: R 1 =Et, R 2 =Cp*, Ar=Ph, n=0, m=1, k=1;

[0035] Complex 3: R 1 =Ad, R 2 =Cp', Ar=Ph, n=1, m=2, k=0, X - =BPh4 - .

[0036] The preferred monodentate thiol and nitrosoarene-bridged binuclear cobalt complexes 1 to 3 have the structure of general formula II:

[0037]

[0038] Table 2 shows the specific structures of the complexes.

[0039] Table 2 Specific structures of preferred monodentate thiol and nitrosoarene bridged binuclear cobalt complexes

[0040]

[0041] Another object of the present invention is to provide a method for preparing a binuclear cobalt nitrosoarene complex, according to Figure 4 Preparation as shown:

[0042] Scheme 1 Preparation method of binuclear cobalt nitrosoarene complex

[0043] (1) Preparation of Thioethyl-bridged Binuclear Cobalt Complex B

[0044] Add 1 to 10 equivalents of ethyl mercaptan to the chloro-bridged binuclear cobalt complex A at -100 to 0°C, maintain the reaction temperature for 0.5 to 2 hours, and then continue the reaction for 1 to 48 hours after the temperature rises to room temperature to obtain the thioethyl-bridged binuclear cobalt complex B;

[0045] Reaction at carbon number C 10 The following ethers, benzene, carbon number C 10 The following alkylbenzenes, carbon number C5~C 10 The reaction is carried out in any one of the solvents selected from alkanes, halogenated alkanes with a carbon number of less than C6, alcohols with a carbon number of less than C5, chlorobenzene, fluorobenzene, acetonitrile, N,N-dimethylformamide, and dimethyl sulfoxide, preferably tetrahydrofuran or ethylene glycol dimethyl ether; the salt used is potassium salt, sodium salt, and lithium salt, preferably sodium ethanethiol;

[0046] (2) Preparation of Thioethyl-bridged Binuclear Cobalt Complex C

[0047] Add 0.5 to 1.5 equivalents of an oxidant to a thioethyl-bridged binuclear cobalt complex B at -100 to 0°C, maintain the reaction at this temperature for 0.5 to 2 hours, and then continue the reaction for 1 to 48 hours after the temperature rises to room temperature to obtain a thioethyl-bridged binuclear cobalt complex C;

[0048] Reaction at carbon number C 10 The following ethers, benzene, carbon number C 10 The following alkylbenzenes, carbon number C5~C 10 The reaction is carried out in any solvent selected from alkanes, halogenated alkanes with carbon numbers below C6, alcohols with carbon numbers below C5, chlorobenzene, fluorobenzene, acetonitrile, N,N-dimethylformamide, and dimethyl sulfoxide, preferably tetrahydrofuran, dichloromethane, and ethylene glycol dimethyl ether; the oxidant used is a bismuth salt of trivalent iron, and the anion is PF6 - 、SbF6 - 、BF4 - , BPh4 - CF3SO3 - 、B(C6F5)4 - and B(3,5-(CF3)2C6H3)4 - ;

[0049] (3) Preparation of dinuclear cobalt complex 1 bridged by thioethyl and nitrosoarene

[0050] The thioethyl-bridged dinuclear cobalt complex C is reacted with 0.5-10 equivalents of nitrosobenzene at –100-25°C for 1-48 hours to obtain the thioethyl- and nitrosoarene-bridged dinuclear cobalt complex 1.

[0051] Reaction at carbon number C 10 The following ethers, benzene, carbon number C 10 The following alkylbenzenes, carbon number C5~C 10 The solvent is any one of alkanes, halogenated alkanes with a carbon number of less than C6, alcohols with a carbon number of less than C5, chlorobenzene, fluorobenzene, acetonitrile, N,N-dimethylformamide, and dimethyl sulfoxide, preferably tetrahydrofuran, dichloromethane, and ethylene glycol dimethyl ether;

[0052] (4) Preparation of dinuclear cobalt complex 2 bridged by thioethyl and nitrosoarene

[0053] The dinuclear cobalt nitrosoarene complex 1 is reacted with 0.5 to 1.2 equivalents of a reducing agent at -100 to 0°C for 0.5 to 5 hours. After the temperature rises to room temperature, the reaction is continued for 1 to 48 hours to obtain a dinuclear cobalt complex 2 bridged by a thioethyl group and a nitrosoarene.

[0054] Reaction at carbon number C 10 The following ethers, benzene, carbon number C 10 The following alkylbenzenes, carbon number C5~C 10 The reaction is carried out in any one of the following solvents: alkanes, alcohols with a carbon number of less than C5, chlorobenzene, fluorobenzene, acetonitrile, N,N-dimethylformamide, and dimethyl sulfoxide, preferably tetrahydrofuran, dichloromethane, and ethylene glycol dimethyl ether; the reducing agent is preferably graphite potassium or cobaltocene;

[0055] (5) Preparation of dinuclear cobalt complex 3 bridged by thioadamantane and nitrosoarene

[0056] ① The dinuclear cobalt complex D bridged by sulfur adamantane is reacted with 0.5 to 10 equivalents of tetraphenyl boron salt at –100 to 0°C for 0.5 to 5 hours;

[0057] ② Add 0.5 to 10 equivalents of nitrosobenzene to the product of step ① at -100 to 0°C, maintain this temperature for 0.5 to 2 hours, and continue the reaction for 1 to 48 hours after the temperature rises to room temperature to obtain a dinuclear cobalt complex 3 bridged by thioadamantane and nitrosoarene;

[0058] Reaction at carbon number C 10 The following ethers, benzene, carbon number C 10 The following alkylbenzenes, carbon number C5~C 10The reaction is carried out in an alkane, a halogenated alkane with a carbon number of C6 or less, an alcohol with a carbon number of C5 or less, chlorobenzene, fluorobenzene, acetonitrile, N,N-dimethylformamide, or dimethyl sulfoxide, preferably in any one of tetrahydrofuran, dichloromethane, or ethylene glycol dimethyl ether.

[0059] The method provided by the present invention also includes steps of product purification, such as distillation, extraction, filtration, etc. The purification steps are common knowledge in the art and are well known to those skilled in the art, and will not be described in detail here.

[0060] Another object of the present invention is to provide an application of a binuclear cobalt complex bridged by a monodentate thiol group and a nitrosoarene, namely, a method for preparing aromatic amines by reducing nitrosoarene compounds catalyzed by the binuclear cobalt complex, comprising the following steps:

[0061] In the presence of borane, a monodentate thiol-bridged dinuclear cobalt complex catalyzes the reduction of nitrosoaromatic compounds to aromatic amines at a temperature of –20 to 50°C for 0.5 to 48 hours.

[0062] The amount of the catalyst is 0.1% to 30% of the amount of the substrate nitrosoaromatic substance;

[0063] The amount of borane used is 1 to 10 times the amount of the nitrosoaromatic substance;

[0064] The substrate is a nitrosoaryl derivative, the aryl group is selected from phenyl and its derivatives, and the hydrogen atom on the benzene ring can be replaced by amino, nitro or halogen.

[0065] The beneficial effects of the present invention compared with the prior art are:

[0066] The binuclear cobalt complex provided by this invention can catalyze the reduction of nitrosoaromatic compounds to aromatic amines in the presence of borane at a reaction temperature of -20 to 50°C for 2 to 48 hours. Currently, the industrial production of aniline is often achieved through the catalytic hydrogenation of nitrobenzene, a method that requires harsh conditions of high temperature and high pressure, with reaction temperatures ranging from 200 to 300°C and pressures of 1 to 3 MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 This is the crystal structure diagram of [Cp*Co(μ-SEt)2(μ-PhNO)CoCp*][PF6] (complex 1);

[0068] Figure 2 is the crystal structure of [Cp*Co(μ-SEt)(μ-PhNO)(t-SEt)CoCp*] (complex 2);

[0069] Figure 3The crystal structure of [Cp'Co(μ-SAd)(μ-PhNO)CoCp'][BPh4] (complex 3) is shown.

[0070] Figure 4 This is a schematic diagram of the preparation method of binuclear cobalt nitrosoarene complexes. DETAILED DESCRIPTION

[0071] The following examples are provided to enable those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used are all commercially available.

[0072] Example 1 Preparation of Complex B

[0073] To a solution of the chlorine-bridged dinuclear cobalt complex A (92 mg) in dichloromethane (6 mL) was added EtSNa (34 mg) under an argon or nitrogen atmosphere at –78°C. The reaction was continued at –78°C for 1 h, and then the temperature was slowly raised to room temperature for 2 h.

[0074] The reaction solution was decompressed to remove the solvent, and n-hexane (5 mL x 3) was added to extract the product. The resulting solution was vacuum-dried to remove the solvent to obtain green powder B (88 mg) with a yield of 86%.

[0075] Example 2 Preparation of Complex C

[0076] In an argon or nitrogen atmosphere, ferrocene hexafluorophosphate (33 mg) was added to a dichloromethane (4 mL) solution of the thioethyl-bridged binuclear cobalt complex B (51 mg) at –78°C. The temperature was maintained and the reaction was continued for 1 h, and then the temperature was slowly raised to room temperature for 2 h.

[0077] The solvent was removed from the reaction solution under reduced pressure, and n-hexane (3 mL×3) was added for washing. The product was dried under reduced pressure to obtain a purple-red powder C (53 mg) with a yield of 79%.

[0078] Example 3 Preparation of dinuclear cobalt complex 1 bridged by thioethyl and nitrosoarene

[0079] In an argon or nitrogen atmosphere, nitrosobenzene (15 mg) was added to a solution of thioethyl-bridged binuclear cobalt complex C (80 mg) in dichloromethane (3 mL) at 25°C, and the reaction was continued at 25°C for 2 h.

[0080] The solvent was removed from the reaction solution under reduced pressure, and n-hexane (3 mL×3) was added for washing. The product was dried under reduced pressure to obtain a brown-red powder 1 (82 mg) with a yield of 86%.

[0081] 1H NMR (400MHz, CD2Cl2, ppm, 25℃): δ-5.28(s), 1.30(s), 1.49(s), 2.18(s), 7.35(s).μ eff (CD2Cl2, Evans' method, 25℃): 2.12μ B .IR(Film,cm -1 ):2965,2926,1647,1578,1480,1445,1377,1240,1160,1084(ν N＝O ),1018,876,840,777,707,666,557.HRMS(ESI,m / z)Calcd for C 30 H 45 Co2NOS2[1-PF6] + ,617.1607,Found 617.1589.Anal.Calcd forC 30 H 45 F6Co2NOPS2:C,47.25;H,5.95;N,1.84.Found:C,47.22;H,6.04;N,1.53.UV / vis(CH2Cl2):λ max / nm(ε / (L·mol -1 cm -1 ))=283(18930),327(27650),368(14610),470(4316).

[0082] Example 4 Preparation of dinuclear cobalt complex 2 bridged by thioethyl and nitrosoarene

[0083] In an argon or nitrogen atmosphere, KC8 (15 mg) was added to a solution of the dinuclear cobalt complex 1 (80 mg) bridged by thioethyl and nitrosobenzene in tetrahydrofuran (3 mL) at –78°C. The mixture was reacted at –78°C for 2 h, and the temperature was slowly raised to room temperature and the reaction was continued for 2 h.

[0084] The reaction solution was decompressed to remove the solvent, and the product was extracted with n-hexane (3 mL × 3). The resulting solution was vacuum-dried to obtain a brown-green powder 2 (40 mg), with a yield of 62%.

[0085] 1H NMR (400MHz, C6D6, ppm, 25℃): δ8.37(s,1H,Ph-H),7.85(s,1H,Ph-H),7.04(s,1H,Ph-H),6.94(s,1H,Ph-H),3.13–2.41(s ,4H,SCH2CH3),1.88(s,3H,SCH2CH3),1.54(s,3H,SCH2CH3),1.31(s,15H,Cp*-CH3),1.08(s,15H,Cp*-CH3).IR(Film,cm -1 ):3049,2958,2904,1583,1480,1447,1372,1243,1193,1154,1070,1024,991(ν N＝O ),765,695,639,595,523.Anal.Calcd for C 30 H 45 Co2NOS2:C,58.34;H,7.34;N,2.27.Found:C,58.49;H 7.55;N,2.29.UV / vis(n-Hex):λ max / nm(ε / (L·mol -1 cm -1 ))=314(28240),577(4150).

[0086] Example 5 Preparation of dinuclear cobalt complex 3 bridged by thioethyl and nitrosoarene

[0087] Under argon or nitrogen atmosphere, NaBPh4 (34 mg) was added to a solution of dinuclear cobalt complex D (85 mg) bridged by thioadamantane in tetrahydrofuran (3 mL) at –78°C. The mixture was stirred for 2 h. A solution of PhNO (11 mg) in tetrahydrofuran was added and the reaction was continued at –78°C for 1 h. The temperature was slowly raised to room temperature and the reaction was continued for 2 h.

[0088] The reaction solution was decompressed to remove the solvent, and n-hexane (3 mL × 3) was added to wash away the by-products. Dichloromethane (3 mL × 3) was then added to extract the product. The resulting solution was vacuum-dried to remove the solvent to obtain a brown-green powder 3 (104 mg) with a yield of 85%.

[0089] 1 H NMR (400MHz, CD2Cl2, ppm, 25℃): δ1.02(s,18H,Cp'- t Bu),1.56(s,18H,Cp'- t Bu),1.65(s,18H,Cp'- tBu),1.85(s,6H,SAd),2.30(s,3H,SAd),2.59(s,6H,SAd),3.85(s,2H,Cp'-H),4.54(s,2H, Cp'-H),6.89–7.33(m,20H,BPh4-H),7.48(s,4H,PhNO-H),8.44(s,1H,PhNO-H).IR(Film,cm -1 ):2958,2923,2854,1660,1581,1463,1365,1259,1167,1101,1031,922(ν N＝O ),808,731,702,613,515.HRMS(ESI,m / z)Calcd for C 50 H 78 Co2NOS[3-BPh4] + ,858.4468,Found 858.4465.Anal.Calcd for C 74 H 98 BCo2NOS:C,75.43;H,8.38;N,1.19.Found:C,75.25;H 8.43;N,1.27.UV / vis(CH2Cl2):λ max / nm(ε / (L·mol -1 cm -1 ))=316(18940),475(4740),594(2810),772(4640).

[0090] The structures of complexes 1 to 3 were characterized by X-ray single crystal diffraction. The crystallographic data are shown in Table 3. Figures 1 to 3 The structural parameters are shown in Tables 4 to 6.

[0091] Table 3 Crystallographic data of complexes 1 to 3

[0092]

[0093] Table 4 Some bond lengths, bond angles and dihedral angles of complex 1

[0094]

[0095] Table 5 Some bond lengths, bond angles and dihedral angles of complex 2

[0096]

[0097] Table 6 Partial bond lengths, bond angles and dihedral angles of complex 3

[0098]

[0099] Example 6 Complex 1 catalyzes the reduction of nitrosobenzene to aniline

[0100] Under argon or nitrogen atmosphere, borane (4 mL, 4.0 mmol) was added to a Schlenk flask containing complex 1 (152 mg, 0.2 mmol), nitrosobenzene (107 mg, 1.0 mmol), and dichloromethane (20 mL). The mixture was allowed to react at room temperature for 12 h. The reaction solution was analyzed by gas chromatography, revealing a 62% aniline yield.

[0101] Example 7 Complex 2 catalyzes the reduction of nitrosobenzene to aniline

[0102] Under argon or nitrogen atmosphere, borane (4 mL, 4.0 mmol) was added to a Schlenk flask containing complex 2 (124 mg, 0.2 mmol), nitrosobenzene (107 mg, 1.0 mmol), and dichloromethane (20 mL). The mixture was allowed to react at room temperature for 12 h. The reaction solution was analyzed by gas chromatography, revealing an aniline yield of 87%.

[0103] The above-described embodiments are only preferred embodiments of the present invention, and are not intended to be all feasible embodiments of the present invention. Any obvious modifications made by a person skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A binuclear cobalt complex bridged by a monodentate thiol group and a nitrosoarene, characterized in that: Has the following structure: In the general structural formula Ⅰ: R 1 Selected from adamantyl or ethyl; R 2 Any one selected from the group consisting of cyclopentadiene ligands, monomethylcyclopentadiene ligands, dimethylcyclopentadiene ligands, trimethylcyclopentadiene ligands, tetramethylcyclopentadiene ligands, pentamethylcyclopentadiene ligands, 1,2,4-tri-tert-butylcyclopentadiene ligands, indene ligands, and fluorene ligands; Ar is selected from phenyl; X - To resist negative ions, selected from PF6 - 、SbF6 - 、BF4 - , BPh4 - CF3SO3 - 、B(C6F5)4 - and B(3,5-(CF3)2C6H3)4 - Any of the following; n is 0, 1, or 2; m is 1 or 2; k is 0 or 1.

2. A method for preparing a binuclear cobalt complex bridged by a monodentate thiol group and a nitrosoarene, characterized in that: Prepare according to the following route:

3. The method for preparing the monodentate thiol-nitrosoarene-bridged binuclear cobalt complex according to claim 2, wherein: The specific preparation method comprises the following steps: (1) Preparation of Thioethyl-bridged Binuclear Cobalt Complex B Add 1 to 10 equivalents of ethyl mercaptan to the chloro-bridged binuclear cobalt complex A at -100 to 0°C, maintain the reaction temperature for 0.5 to 2 hours, and then continue the reaction for 1 to 48 hours after the temperature rises to room temperature to obtain the thioethyl-bridged binuclear cobalt complex B; (2) Preparation of Thioethyl-bridged Binuclear Cobalt Complex C Add 0.5 to 1.5 equivalents of an oxidant to a thioethyl-bridged binuclear cobalt complex B at -100 to 0°C, maintain the reaction at this temperature for 0.5 to 2 hours, and then continue the reaction for 1 to 48 hours after the temperature rises to room temperature to obtain a thioethyl-bridged binuclear cobalt complex C; (3) Preparation of dinuclear cobalt complex 1 bridged by thioethyl and nitrosoarene The thioethyl-bridged dinuclear cobalt complex C is reacted with 0.5-10 equivalents of nitrosobenzene at –100-25°C for 1-48 hours to obtain the thioethyl- and nitrosoarene-bridged dinuclear cobalt complex 1. (4) Preparation of dinuclear cobalt complex 2 bridged by thioethyl and nitrosoarene The dinuclear cobalt nitrosoarene complex 1 is reacted with 0.5 to 1.2 equivalents of a reducing agent at -100 to 0°C for 0.5 to 5 hours. After the temperature rises to room temperature, the reaction is continued for 1 to 48 hours to obtain a dinuclear cobalt complex 2 bridged by a thioethyl group and a nitrosoarene. (5) Preparation of dinuclear cobalt complex 3 bridged by thioadamantane and nitrosoarene ① The dinuclear cobalt complex D bridged by sulfur adamantane is reacted with 0.5 to 10 equivalents of sodium tetraphenylborate at -100 to 0°C for 0.5 to 5 hours; ② Add 0.5 to 10 equivalents of nitrosobenzene to the product of step ① at -100 to 0°C, maintain this temperature for 0.5 to 2 hours, and continue the reaction for 1 to 48 hours after the temperature rises to room temperature to obtain a dinuclear cobalt complex 3 bridged by thioadamantane and nitrosoarene; The reaction of steps (1), (2), (3) and (5) is carried out at a carbon number C 10 The following ethers, benzene, carbon number C 10 The following alkylbenzenes, carbon number C5~C 10 The reaction is carried out in any solvent selected from alkanes, halogenated alkanes with a carbon number of less than C6, alcohols with a carbon number of less than C5, chlorobenzene, fluorobenzene, acetonitrile, N,N-dimethylformamide, and dimethyl sulfoxide; The reaction in step (4) is carried out at carbon number C 10 The following ethers, benzene, carbon number C 10 The following alkylbenzenes, carbon number C5~C 10 Alkanes, alcohols with carbon numbers below C5, chlorobenzene, fluorobenzene, acetonitrile, N,N-dimethylformamide, and dimethyl sulfoxide; The ethanethiolate in step (1) is a sodium salt; The oxidant in step (2) is ferrocene hexafluorophosphate; The reducing agent in step (4) is graphite potassium.

4. Application of a binuclear cobalt complex bridged by a monodentate thiol group and a nitrosoarene, characterized in that: The application of the catalytic reduction of aromatic amines comprises the following steps: In the presence of borane, a monodentate thiol-bridged dinuclear cobalt complex catalyzes the reduction of nitrosoarene to aromatic amine in an argon or nitrogen atmosphere. -20~50℃, reaction time 0.5~48h; The amount of the monodentate thiol group and the nitroso aromatic hydrocarbon bridged binuclear cobalt complex is 0.1% to 30% of the amount of the substrate nitroso aromatic hydrocarbon substance; The amount of borane used is 1 to 10 times the amount of the nitrosoaromatic substance.

5. Use of the monodentate thiol- and nitrosoarene-bridged binuclear cobalt complex according to claim 4, characterized in that: The nitroso aromatic hydrocarbon is nitrosophenyl.

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