A bis-silane pincer type iron dinitrogen complex and a preparation method and application thereof

Abstract

The application discloses a double-silicon bin pincer type iron dinitrogen gas complex as well as a preparation method and application thereof, belongs to the technical field of nitrogen silicon amination catalysis, and is characterized in that, under a protective atmosphere, a [SiC(sp 2 )Si] type double-silicon bin pincer ligand and FeCl2 are used as raw materials, a coordination reaction is carried out in a tetrahydrofuran solvent at room temperature, and a [SiC(sp 2 )Si] type double-silicon bin iron chloride is obtained; under a nitrogen atmosphere, the [SiC(sp 2 )Si] type double-silicon bin iron chloride and KC8 are used as raw materials, a reduction coordination reaction is carried out in a tetrahydrofuran solvent at room temperature, and a double-silicon bin pincer type iron dinitrogen gas complex is obtained. The application prepares the first [SiC(sp 2 )Si] type double-silicon bin pincer type iron dinitrogen gas complex. The double-silicon bin pincer type iron dinitrogen gas complex prepared above is used for catalyzing a nitrogen silicon amination reaction, and exhibits good catalytic effect, and the catalyst conversion number is up to 476.3.

Description

Technical Field

[0001] This invention relates to the field of nitrogen silane amination catalysis technology, specifically to a dual-silicon clamp-type iron-nitrogen complex and its preparation method and application. Background Technology

[0002] The efficient synthesis of nitrogen-containing organic compounds directly from nitrogen has long been a challenge in chemical research. Currently, there are three main methods for ammonia synthesis: the Haber-Boash process, high-energy nitrogen fixation, and biological nitrogen fixation. The Haber-Boash process is the most important method in industrial production, synthesizing approximately 160 million tons of ammonia annually, playing a crucial role in industrial production. However, this process requires high-temperature and high-pressure reaction conditions, consuming 1% to 2% of the world's energy annually and releasing 450 million tons of carbon dioxide, causing a certain degree of impact on the ecological environment. High-energy nitrogen fixation utilizes the enormous energy of lightning to convert nitrogen into ammonia; while this method does not require additional energy, it is subject to randomness. Biological nitrogen fixation can achieve efficient conversion of nitrogen to ammonia under mild conditions, but the reaction mechanism of biological nitrogen fixation remains unclear.

[0003] Transition metal complexes have demonstrated excellent performance in catalytic nitrogen reduction reactions. In recent years, although metal complexes such as molybdenum, iron, and cobalt have achieved significant breakthroughs in nitrogen reduction reactions, successfully converting nitrogen into nitrogen-containing organic compounds, they still cannot replace the Haber-Bosch ammonia synthesis process. Furthermore, relevant literature mainly focuses on organophosphorus or nitrogen heterocyclic carbene transition metal complexes; reports on the application of silane transition metal complexes in nitrogen reduction reactions are very rare.

[0004] Silicon benzenes, as structural analogs of carbenes, possess unique σ-electron donor properties and π-feedback acceptor capabilities, and have become important structural units in the field of organosilicon chemistry. Silicon benzene transition metal complexes exhibit unique advantages in terms of catalytic efficiency, chemoselectivity, and reaction mechanisms in homogeneous catalytic reactions. Although significant progress has been made in various homogeneous catalytic reactions using silicon benzene transition metal complexes, their application in nitrogen reduction reactions remains in its early stages. In 2018, Professor Cui Chunming's research group published in [Journal Name - missing from original text]. Chem.CommunA single-silylene-tethered silylene ligand and enabling reversible dinitrogen binding to iron and catalytic silylation were reported in the journal *Organometallics*, and a clamp-type silylene-tethered silylene-nitrogen complex was reported in a 2020 paper by Li's research group in *Organometallics*, titled "N2 Silylation Catalyzed by a Bis(silylene)-Based [SiCSi] PincerHydrido Iron(II) Dinitrogen Complex." Both of these complexes exhibited relatively low catalyst conversion numbers in the nitrogen silylation reaction, indicating that their catalytic efficiency needs further improvement. Summary of the Invention

[0005] This invention provides a dual-silicon clamp-type iron-nitrogen complex, its preparation method, and its application. It effectively solves the technical problems of poor catalytic effect and low catalyst conversion number of existing single-silicon clamp-type iron-nitrogen complexes and clamp-type silicon clamp-type iron-nitrogen complexes in catalyzing nitrogen silanization reactions. This invention provides a dual-silicon clamp-type iron-nitrogen complex that exhibits better catalytic effect in nitrogen silanization reactions, with a catalyst conversion number as high as 476.3.

[0006] The first objective of this invention is to provide a method for preparing a bis-silicon clamp-type iron-nitrogen complex, comprising the following steps:

[0007] S1, under a protective atmosphere, with [SiC(sp 2 Using [SiC(sp2)Si]-type bis-silicon ligands and FeCl2 as raw materials, a coordination reaction was carried out in tetrahydrofuran solvent at room temperature to obtain [SiC(sp2)Si]-type bis-silicon ferric chloride.

[0008] S2, with nitrogen as a ligand, and the [SiC(sp... 2 Using ferric chloride of the [Si] type as raw material and KC8 as reducing agent, a reduction-coordination reaction occurs at room temperature in tetrahydrofuran solvent, [SiC(sp...]... 2 [Si]-type bis(silyl) ferric chloride is reduced while nitrogen gas coordinates to the iron center, forming a zero-valent iron complex. The iron center of the zero-valent iron complex activates the C(sp) of the phenyl group in the zero-valent iron complex. 2 The -H bond undergoes an addition reaction to yield a bis-silicon clamp-type iron-nitrogen complex.

[0009] As a preferred embodiment, the [SiC(sp 2The molar ratio of the Si-type double silicon clamp ligand, FeCl2, and KC8 is 1:1.1:2.2.

[0010] In a preferred embodiment, in S2, before the reduction coordination reaction occurs, [SiC(sp...] is subjected to a nitrogen atmosphere at -78°C to -50°C. 2 When a tetrahydrofuran solution of ferric chloride of the bis(Si) type is added to a tetrahydrofuran suspension of KC8, a reduction coordination reaction occurs after the temperature returns to room temperature.

[0011] In a preferred embodiment, after the reduction coordination reaction is completed, the solvent is removed to obtain a crude product. The crude product is extracted with n-pentane, filtered, and crystals are precipitated at 0℃~2℃ to obtain a bis-silicon clamp-type iron-nitrogen complex.

[0012] In a preferred embodiment, in S1, under a protective atmosphere, a tetrahydrofuran solution of FeCl2 is heated to 59°C~61°C, and [SiC(sp)] is added at -80°C~-78°C. 2 A tetrahydrofuran solution of a Si-type double silicon clamp ligand was subjected to a coordination reaction after being restored to room temperature.

[0013] In a preferred embodiment, after the coordination reaction is completed, the solvent is removed to obtain the initial product, which is then washed with n-pentane to obtain [SiC(sp... 2 )Si] type bis-silicon ferric chloride.

[0014] In a preferred embodiment, in S1, the coordination reaction takes 2 to 3 hours; in S2, the reduction coordination reaction takes 20 to 24 hours.

[0015] The second objective of this invention is to provide a dual-silicon clamp-type iron-nitrogen complex, which is prepared using any of the preparation methods described above.

[0016] The third objective of this invention is to provide an application of the above-mentioned bis-silicon clamp-type iron-nitrogen complex in a catalytic nitrogen silanization reaction. Under a nitrogen atmosphere, using Me3SiCl as the silanizing agent, KC8 as the reducing agent, 1,4-dioxane as the solvent, and the aforementioned bis-silicon clamp-type iron-nitrogen complex as the catalyst, the catalytic reaction is carried out at room temperature.

[0017] In a preferred embodiment, the molar ratio of Me3SiCl, KC8 and the dual-silicon clamp-type iron-nitrogen complex is 6:6:0.001.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] This invention provides a method for preparing a double-silicon clamp-type iron-nitrogen complex, wherein, under a protective atmosphere, [SiC(sp... 2 Using [Si]-type bisilicon clamp ligands and FeCl2 as raw materials, a coordination reaction occurs in tetrahydrofuran solvent at room temperature to yield [SiC(sp... 2 [Si] type bis-silicon ferric chloride; using nitrogen as a ligand, with the [SiC(sp] 2 Using ferric chloride of the [Si] type as raw material and KC8 as reducing agent, a reduction-coordination reaction occurs at room temperature in tetrahydrofuran solvent, [SiC(sp...]... 2 [Si]-type bis(silyl) ferric chloride is reduced while nitrogen gas coordinates to the iron center, forming a zero-valent iron complex. The iron center of the zero-valent iron complex activates the C(sp) of the phenyl group in the zero-valent iron complex. 2 The -H bond undergoes an addition reaction to yield a bis-silicon clasp-type iron-nitrogen complex. This invention provides the first example of a bis-silicon clasp-type [SiC(sp...] 2 The prepared bis-silicon clamp-type iron-nitrogen complex exhibited good catalytic performance in the catalytic nitrogen silaneation reaction, with a catalyst conversion number as high as 476.3 equivalents. Attached Figure Description

[0020] Figure 1 The [SiC(sp)] prepared in Example 1 of this invention 2 Schematic diagram of the synthesis of ferric chloride of the ]Si type.

[0021] Figure 2 The [SiC(sp)] prepared in Example 1 of this invention 2 Schematic diagram of the synthesis of )Si] type double silicon clamp iron double nitrogen complex.

[0022] Figure 3 The [SiC(sp)] prepared in Example 1 of this invention 2 Molecular structure diagram of the Si-type double silicon clamp-type iron double nitrogen complex.

[0023] Figure 4 The [SiC(sp)] prepared in Example 1 of this invention 2 Infrared spectrum of the solid state of the ]Si-type double silicon clamp-type iron double nitrogen complex. Detailed Implementation

[0024] To enable those skilled in the art to better understand and implement the technical solutions of this invention, the invention is further described below with reference to specific embodiments. However, the embodiments are not intended to limit the invention. Unless otherwise specified, the following test methods and detection methods are conventional methods; unless otherwise specified, the reagents and raw materials are commercially available.

[0025] The background section of this invention mentions that although silicon benzene transition metal complexes have made significant progress in various homogeneous catalytic reactions, their application in nitrogen reduction reactions is still in its early stages. The single silicon benzene-iron-nitrogen complex reported by Professor Cui Chunming's research group in 2018 and the clamp-type silicon benzene-iron-nitrogen complex reported by Professor Li's research group in 2020 showed a catalyst conversion number of only 74.4 in nitrogen silanization reactions, which is relatively low, indicating that the catalytic effect needs further improvement. To address the above-mentioned technical problems, this invention provides a dual silicon benzene clamp-type iron-nitrogen complex, its preparation method, and its application.

[0026] The technical solution of the present invention will be described in detail below.

[0027] This invention provides a method for preparing a bis-silicon clamp-type iron-nitrogen complex, comprising the following steps:

[0028] S1, under a protective atmosphere, with [SiC(sp 2 Using [Si]-type bisilicon clamp ligands and FeCl2 as raw materials, a coordination reaction was carried out in tetrahydrofuran solvent at room temperature for 2-3 hours to obtain [SiC(sp... 2 )Si] type bis-silicon ferric chloride.

[0029] S2, with nitrogen as a ligand, and the [SiC(sp... 2 Using ferric chloride of the [Si] type as raw material and KC8 as reducing agent, a reduction coordination reaction is carried out in tetrahydrofuran solvent at room temperature for 20-24 hours to produce [SiC(sp... 2 [Si]-type bis(silyl) ferric chloride is reduced while nitrogen gas coordinates to the iron center, forming a zero-valent iron complex. The iron center of the zero-valent iron complex activates the C(sp) of the phenyl group in the zero-valent iron complex. 2 The -H bond undergoes an addition reaction to yield a bis-silicon clamp-type iron-nitrogen complex.

[0030] The double-silicon clamp-type iron-nitrogen complex prepared using the above-mentioned technical solution exhibits good catalytic performance in the catalytic reaction of nitrogen silanization, with a catalyst conversion number as high as 476.3.

[0031] To improve the yield and purity of the double-silicon clamp-type iron-nitrogen complex, the [SiC(sp...] 2 The molar ratio of the [Si]-type bisilicon clamp ligand, FeCl2, and KC8 is 1:1.1:2.2. If the molar ratio of KC8 is less than the specified 2.2, such as a 1:1:2 molar ratio, the reactants will react incompletely, leaving residual reactants in the reaction system, which will also affect the reaction yield and purity.

[0032] It should be noted that, in order to control the reaction rate and avoid the formation of byproducts during the reaction, in S2, before the reduction coordination reaction occurs, [SiC(sp...] is subjected to low temperature at -78℃ to -50℃ under a nitrogen atmosphere. 2 When a tetrahydrofuran solution of ferric chloride of the bis(Si) type is added to a tetrahydrofuran suspension of KC8, a reduction coordination reaction occurs after the temperature returns to room temperature.

[0033] To purify the final product, the bis-silicon clamp-type iron-nitrogen complex, the solvent was removed after the reduction coordination reaction to obtain a crude product. The crude product was extracted with n-pentane, filtered, and crystals were precipitated at 0℃~2℃ to obtain the bis-silicon clamp-type iron-nitrogen complex.

[0034] It should be noted that in S1, under a protective atmosphere, the tetrahydrofuran solution of FeCl2 is heated at 59℃~61℃, and [SiC(sp)] is added at -80℃~-78℃. 2 The tetrahydrofuran solution of the [Si]-type bisilicon clamp ligand was brought to room temperature before the coordination reaction was carried out. Since FeCl2 has low solubility in tetrahydrofuran, heating is beneficial for the first step of the reaction, while the second step requires mixing at low temperature to reduce the reaction rate and avoid the formation of unnecessary byproducts.

[0035] In order to obtain high purity [SiC(sp... 2 After the coordination reaction of [Si]-type bis(silyl) ferric chloride is completed, the solvent is removed to obtain the initial product. The initial product is washed with n-pentane to obtain [SiC(sp... 2 )Si] type bis-silicon ferric chloride.

[0036] The invention will now be described in detail through the following embodiments and comparative examples.

[0037] Example 1

[0038] A method for preparing a bis-silicon clamp-type iron-nitrogen complex includes the following steps:

[0039] S1, as Figure 1 As shown, under a nitrogen atmosphere, 1.26 mmol (0.16 g) of FeCl2 was dissolved in 20 mL of tetrahydrofuran and heated at 60 °C for 30 min to obtain a tetrahydrofuran solution of FeCl2; 1.14 mmol (0.78 g) of [SiC(sp... 2 The [Si]-type bisilicon clamp ligand was dissolved in 30 mL of tetrahydrofuran to obtain [SiC(sp... 2 [Si]-type bisilicon clamp ligand tetrahydrofuran solution; at -78℃, [SiC(sp 2A solution of [SiC(sp)]-type bisilicon clamp ligand in tetrahydrofuran was slowly added to a solution of FeCl2 in tetrahydrofuran. After returning to room temperature, the reaction continued for 3 hours, and the color turned pale yellow. The solvent was removed under vacuum, and the mixture was washed with 20 mL of n-pentane to obtain a pale yellow powder, which is [SiC(sp)] 2 The yield of ferric chloride of the )Si type was 0.60g, with a yield of 75%.

[0040] S2, as Figure 2 As shown, under a nitrogen atmosphere at -78°C, 1.26 mmol, or 1.02 g, of [SiC(sp)] was added. 2 1)Si-type bis(silyl)benzene ferric chloride was dissolved in 30 mL of tetrahydrofuran and slowly added to a suspension prepared by 2.52 mmol (0.34 g) of KC8 and 30 mL of tetrahydrofuran. After returning to room temperature, the reaction was continued for 24 h, and the color turned dark brownish-yellow. The solvent was removed under vacuum, and the mixture was extracted with 50 mL of n-pentane and filtered. A large amount of light yellow flaky crystals precipitated at 0 °C, which is the bis(silyl)benzene ferric-nitrogen complex. Its molecular structure is as follows: Figure 3 As shown, the yield was 0.63g, with a yield rate of 70%.

[0041] Figure 4 The image shows the infrared spectrum of the solid state of the bis-silicon clamp-type iron-nitrogen complex prepared in Example 1. Figure 4 It can be seen that, in the infrared spectrum, the stretching vibration peak of typical terminally coordinated nitrogen gas is located at 2101 cm⁻¹. -1 2070cm -1 and 2043cm -1 At 1891cm -1 and 1847cm -1 Typical iron-hydrogen stretching vibration signals are present, which is consistent with the structure of iron-nitrogen complexes.

[0042] Example 2

[0043] A method for preparing a bis-silicon clamp-type iron-nitrogen complex includes the following steps:

[0044] S1, under a nitrogen atmosphere, 1.26 mmol (0.16 g) of FeCl2 was dissolved in 20 mL of tetrahydrofuran and heated at 60 °C for 30 min to obtain a tetrahydrofuran solution of FeCl2; 1.14 mmol (0.78 g) of [SiC(sp... 2 The [Si]-type bisilicon clamp ligand was dissolved in 30 mL of tetrahydrofuran to obtain [SiC(sp... 2 [Si]-type bisilicon clamp ligand tetrahydrofuran solution; at -78℃, [SiC(sp 2A tetrahydrofuran solution of the Si-type double silicon clamp ligand was slowly added to a tetrahydrofuran solution of FeCl2. After returning to room temperature, the reaction continued for 3 hours, and the color turned light yellow, yielding the first reaction system.

[0045] S2, under a nitrogen atmosphere at -78°C, the above first reaction system was slowly added to a suspension prepared from 2.52 mmol (0.34 g) of KC8 and 30 mL of tetrahydrofuran. After returning to room temperature, the reaction was continued for 24 h, and the color turned dark brownish-yellow. The solvent was removed under vacuum, and the mixture was extracted with 50 mL of n-pentane and filtered. A large amount of light yellow flaky crystals precipitated at 0°C, which is the bis-silicon clamp-type iron-nitrogen complex, with a yield of 0.63 g and a yield of 70%.

[0046] Example 3

[0047] A method for preparing a bis-silicon clamp-type iron-nitrogen complex includes the following steps:

[0048] S1, under a nitrogen atmosphere, 1.26 mmol (0.16 g) of FeCl2 was dissolved in 20 mL of tetrahydrofuran and heated at 60 °C for 30 min to obtain a tetrahydrofuran solution of FeCl2; 1.14 mmol (0.78 g) of [SiC(sp... 2 The [Si]-type bisilicon clamp ligand was dissolved in 30 mL of tetrahydrofuran to obtain [SiC(sp... 2 [Si]-type bisilicon clamp ligand tetrahydrofuran solution; at -80℃, [SiC(sp 2 A solution of [SiC(sp)]-type bisilicon clamp ligand in tetrahydrofuran was slowly added to a solution of FeCl2 in tetrahydrofuran. After returning to room temperature, the reaction continued for 2 hours, and the color turned pale yellow. The solvent was removed under vacuum, and the powder was washed with 20 mL of n-pentane to obtain a pale yellow powder, which is [SiC(sp)] 2 The yield of ferric chloride of the )Si type was 0.58g, with a yield of 72%.

[0049] S2, under a nitrogen atmosphere at -65°C, 1.26 mmol, or 1.02 g, of [SiC(sp... 2 The bis(silyl)benzene ferric chloride was dissolved in 30 mL of tetrahydrofuran and slowly added to a suspension prepared by 2.52 mmol (0.34 g) of KC8 and 30 mL of tetrahydrofuran. After returning to room temperature, the reaction was continued for 20 h, and the color turned dark brownish-yellow. The solvent was removed under vacuum, and the mixture was extracted with 50 mL of n-pentane and filtered. A large amount of light yellow flaky crystals precipitated at 2 °C, which was the bis(silyl)benzene clamp-type iron-nitrogen complex, with a yield of 0.60 g and a yield of 68%.

[0050] Example 4

[0051] A method for preparing a bis-silicon clamp-type iron-nitrogen complex includes the following steps:

[0052] S1, under a nitrogen atmosphere, 1.26 mmol (0.16 g) of FeCl2 was dissolved in 20 mL of tetrahydrofuran and heated at 60 °C for 30 min to obtain a tetrahydrofuran solution of FeCl2; 1.14 mmol (0.78 g) of [SiC(sp... 2 The [Si]-type bisilicon clamp ligand was dissolved in 30 mL of tetrahydrofuran to obtain [SiC(sp... 2 [Si]-type bisilicon clamp ligand tetrahydrofuran solution; at -79℃, [SiC(sp 2 A solution of [SiC(sp)]-type bisilicon clamp ligand in tetrahydrofuran was slowly added to a solution of FeCl2 in tetrahydrofuran. After returning to room temperature, the reaction continued for 2.5 h, and the color turned pale yellow. The solvent was removed under vacuum, and the product was washed with 20 mL of n-pentane to obtain a pale yellow powder, which is [SiC(sp)] 2 The yield of ferric chloride of the )Si type was 0.56g, with a yield of 70%.

[0053] S2, under a nitrogen atmosphere at -50°C, 1.26 mmol, or 1.02 g, of [SiC(sp...] was added. 2 The bis(silyl)benzene ferric chloride was dissolved in 30 mL of tetrahydrofuran and slowly added to a suspension prepared by 2.52 mmol (0.34 g) of KC8 and 30 mL of tetrahydrofuran. After returning to room temperature, the reaction was continued for 22 h, and the color turned dark brownish-yellow. The solvent was removed under vacuum, and the mixture was extracted with 50 mL of n-pentane and filtered. A large amount of light yellow flaky crystals precipitated at 1 °C, which was the bis(silyl)benzene clamp-type iron-nitrogen complex, with a yield of 0.62 g and a yield of 68.6%.

[0054] To illustrate the catalytic effect of the bis-silicon clamp-type iron-nitrogen complexes prepared in Examples 1 to 4 above, the present invention also provides the following application examples.

[0055] Application Example 1

[0056] Under a nitrogen atmosphere, 30 mmol Me3SiCl was used as the silanizing agent, 30 mmol KC8 as the reducing agent, and 0.005 mmol of the bis-silicon clamp-type iron-nitrogen complex prepared in Example 1 was used as the catalyst. 1 mmol n-dodecane was used as the internal standard solution and 20 mL of 1,4-dioxane was used as the solvent. The solutions were added to 100 mL round-bottom flasks and the reaction was carried out at 25 °C for 20 h. After the reaction was completed, the reaction solution was centrifuged, and the supernatant was subjected to GC detection to determine the amount of silane produced. The catalyst conversion number could then be calculated.

[0057] Application Example 2

[0058] Under a nitrogen atmosphere, 30 mmol Me3SiCl was used as the silanizing agent, 30 mmol KC8 as the reducing agent, and 0.005 mmol of the bis-silicon clamp-type iron-nitrogen complex prepared in Example 2 was used as the catalyst. 1 mmol n-dodecane was used as the internal standard solution and 20 mL of 1,4-dioxane was used as the solvent. The solutions were added to 100 mL round-bottom flasks and the reaction was carried out at 25 °C for 20 h. After the reaction was completed, the reaction solution was centrifuged, and the supernatant was subjected to GC detection to determine the amount of silane produced. The catalyst conversion number could then be calculated.

[0059] Application Example 3

[0060] Under a nitrogen atmosphere, 30 mmol Me3SiCl was used as the silanizing agent, 30 mmol KC8 as the reducing agent, and 0.005 mmol of the bis-silicon clamp-type iron-nitrogen complex prepared in Example 3 was used as the catalyst. 1 mmol n-dodecane was used as the internal standard solution and 20 mL of 1,4-dioxane was used as the solvent. The solutions were added to 100 mL round-bottom flasks and the reaction was carried out at 25 °C for 20 h. After the reaction was completed, the reaction solution was centrifuged, and the supernatant was subjected to GC detection to determine the amount of silane produced. The catalyst conversion number could then be calculated.

[0061] Application Example 4

[0062] Under a nitrogen atmosphere, 30 mmol Me3SiCl was used as the silanizing agent, 30 mmol KC8 as the reducing agent, and 0.005 mmol of the bis-silicon clamp-type iron-nitrogen complex prepared in Example 4 was used as the catalyst. 1 mmol n-dodecane was used as the internal standard solution and 20 mL of 1,4-dioxane was used as the solvent. The solutions were added to 100 mL round-bottom flasks and the reaction was carried out at 25 °C for 20 h. After the reaction was completed, the reaction solution was centrifuged, and the supernatant was subjected to GC detection to determine the amount of silane produced. The catalyst conversion number could then be calculated.

[0063] The catalytic performance of the double-silicon clamp-type iron-nitrogen complexes provided in Examples 1 to 4 was tested. The double-silicon clamp-type iron-nitrogen complexes prepared in this invention were used as catalysts to catalyze the silanization reaction of nitrogen to generate silane compounds. The conversion number of the catalyst was the ratio of the number of moles of the product silane compound to the number of moles of the catalyst. The specific results are shown in Table 1.

[0064] Table 1. Catalytic effects of the bis-silicon clamp-type iron-nitrogen complexes prepared in Examples 1-4 of this invention.

[0065]

[0066] As shown in Table 1, the bis-silicon-iron-nitrogen complex prepared by this invention has excellent catalytic performance, with a conversion number as high as 476.3.

[0067] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing a double-silicon clamp-type iron-nitrogen complex, characterized in that, Includes the following steps: Under a protective atmosphere, a tetrahydrofuran solution of FeCl2 was heated at 59℃~61℃, and [SiC(sp)] was added at -80℃~-78℃. 2 A tetrahydrofuran solution of a [Si]-type bisilicon clamp ligand, after being restored to room temperature, undergoes a coordination reaction to yield [SiC(sp... 2 [Si]-type bis-silicon ferric chloride; the coordination reaction time is 2h~3h; Using nitrogen as a ligand, and the [SiC(sp... 2 Using [Si]-type bis(s)silyl ferric chloride as raw material, KC8 as reducing agent, and tetrahydrofuran as solvent, under a nitrogen atmosphere at -78℃ to -50℃, [SiC(s)silyl ferric chloride is used to react the raw material with KC8 as reducing agent and tetrahydrofuran as solvent. 2 A tetrahydrofuran solution of ferric chloride of the [Si] type was added to a tetrahydrofuran suspension of KC8. Upon returning to room temperature, a reduction coordination reaction occurred, [SiC(sp... 2 [Si]-type bis(silyl) ferric chloride is reduced while nitrogen gas coordinates to the iron center, forming a zero-valent iron complex. The iron center of the zero-valent iron complex activates the C(sp) of the phenyl group in the zero-valent iron complex. 2 The -H bond undergoes an addition reaction to yield a bis-silicon clamp-type iron-nitrogen complex; the [SiC(sp 2 The molar ratio of the [Si]-type bisilicon clamp ligand, FeCl2, and KC8 is 1:1.1:2.2; the reduction coordination reaction time is 20h~24h. The synthetic route for the dual-silicon clamp-type iron-nitrogen complex is as follows: ， 。 2. The method for preparing the dual-silicon clamp-type iron-nitrogen complex according to claim 1, characterized in that, After the reduction coordination reaction is completed, the solvent is removed to obtain a crude product. The crude product is extracted with n-pentane, filtered, and crystals are precipitated at 0℃~2℃ to obtain a bis-silicon clamp-type iron-nitrogen complex.

3. The method for preparing the double-silicon clamp-type iron-nitrogen complex according to claim 1, characterized in that, After the coordination reaction is completed, the solvent is removed to obtain the initial product. The initial product is washed with n-pentane to obtain [SiC(sp 2 )Si] type bis-silicon ferric chloride.

4. A dual-silicon clamp-type iron-nitrogen complex, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 3.

5. The application of the double-silicon clamp-type iron-nitrogen complex according to claim 4 in the catalytic nitrogen silanization reaction, characterized in that, Under a nitrogen atmosphere, using Me3SiCl as the silanizing agent, KC8 as the reducing agent, 1,4-dioxane as the solvent, and the aforementioned bis-silicon clamp-type iron-nitrogen complex as the catalyst, a catalytic reaction was carried out at room temperature to obtain a silane compound.

6. The application according to claim 5, characterized in that, The molar ratio of Me3SiCl, KC8 and the bis-silicon clamp-type iron-nitrogen complex is 6:6:0.001.

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