Preparation method and catalytic application of novel imino phosphine ligand copper (I) complex

Abstract

The invention relates to the field of chemistry, and discloses a synthesis method of four novel imino phosphine ligand Cu (I) complexes and application of the complexes as catalysts in a hydrogen-silicon reduction reaction of ketone. The yield of most of the novel imino phosphine ligand Cu (I) complexes is not lower than 70%, the preparation process is simple, and the product is easy for single crystal culture; and under relatively mild reaction conditions, the catalyst shows certain catalytic activity for catalyzing hydrosilylation reaction of acetophenone. In addition, a copper-based catalyst and a hydride donor (PMHS) are adopted, so that the catalytic system is cleaner and more efficient, and the cost can be greatly saved.

Description

Technical Field

[0003] The present invention relates to a catalytic material in the field of chemistry, and specifically designs a synthesis method of four novel iminophosphine ligand copper(I) complexes and their application as catalysts in the hydrosilylation reduction reaction of ketones. Background Art

[0004] Alcohol compounds are important intermediates for a variety of chemical industrial products. Therefore, the development of economical and efficient catalysts for the reduction reaction of ketones has become one of the important directions in modern chemical research. There are three types of reduction reactions of ketones: hydrogenation reduction, transfer hydrogenation reaction, and hydrosilylation reaction. Among them, the hydrosilylation reduction of ketones has the advantages of milder reaction conditions, fewer side reactions, and simpler operation compared with the other two methods. It is widely used in the synthesis of secondary alcohols and thus widely applied in the fields of organic synthesis, fine chemicals, etc. In the past, most of the catalysts for the reduction reaction of ketones were noble metals. However, due to cost considerations and the increasing environmental protection requirements, researchers have been striving to seek various non-noble metals to replace noble metals in catalyzing the hydrosilylation reaction of ketones and have made certain progress. However, there is still a large room for exploration in the development of non-noble metal catalysts for efficiently catalyzing the reduction reaction of ketones. Continuing to develop non-noble metal catalysts with high activity and high selectivity remains an important research direction.

[0005] In recent years, various non-noble metal complexes stabilized by amine-phosphine ligands have shown good catalytic effects in the hydrosilylation reaction of ketones. Among them, the Cu metal has the characteristics of rich content in nature and strong coordination ability, which have been noticed and studied by more and more scientific researchers. Currently, amine-phosphine ligand Cu complexes with relatively high activity have been developed and applied to catalyze the hydrosilylation reaction of ketones. On the basis of this research, we tried to design several novel iminophosphine ligands by ourselves. Under simpler operating conditions, target iminophosphine ligands were obtained by reacting cheaper amine compounds with precursor aldehyde compounds. Then, these ligands were combined with cheap and low-toxic metal Cu(I) to obtain the expected Cu(I) complexes. Further, these complexes were used to catalyze the hydrosilylation reaction of ketones to explore the catalytic performance of these Cu(I) complexes in the hydrosilylation reaction of ketones, and analyze them in combination with the structural characteristics of the complexes themselves, summarize the correlation between their catalytic activity and structure, and provide a reference for further designing Cu(I) complexes with higher catalytic activity in the future. Summary of the Invention

[0006] The purpose of the present invention is to provide a synthesis method of a class of novel iminophosphine ligand copper(I) complexes and their application as catalytic materials in the hydrosilylation reduction reaction of ketones in view of the problems existing in the prior art.

[0007] To achieve the above technical objectives, the present invention provides four novel iminophosphine ligand copper(I) complexes, which are respectively of the structures of Formula 1 - Formula 4:

[0008]

[0009] The synthetic route of the iminophosphine ligand copper(I) complex is as follows:

[0010] Dissolve the iminophosphine ligand N,N'-[o-(diphenylphosphino)benzylidene]-4-benzoic acid amide and the copper salt [Cu(MeCN) 4 BF 4 in a dichloromethane / acetonitrile mixed solution, stir and react at room temperature, and the iminophosphine ligand copper(I) complex of Formula 1 structure can be obtained after treatment;

[0011] Dissolve the iminophosphine ligand N,N'-[o-(diphenylphosphino)benzylidene]-4-(methoxy)aniline and the copper salt [Cu(MeCN) 4 BF 4 in a dichloromethane / acetonitrile mixed solution, stir and react at room temperature, and the iminophosphine ligand copper(I) complex of Formula 2 structure can be obtained after treatment;

[0012] Dissolve the iminophosphine ligand N,N'-bis[o-(diphenylphosphino)benzylidene]ethylenediamine and the copper salt [Cu(MeCN) 4 BF 4 in a dichloromethane / acetonitrile mixed solution, stir and react at room temperature, and the iminophosphine ligand copper(I) complex of Formula 3 structure can be obtained after treatment;

[0013] Dissolve the iminophosphine ligand N,N'-bis[o-(diphenylphosphino)benzylidene]-1,4-butanediamine and the copper salt [Cu(MeCN) 4 BF 4 in a dichloromethane / acetonitrile mixed solution, stir and react at room temperature, and the iminophosphine ligand copper(I) complex of Formula 4 structure can be obtained after treatment;

[0014] The above copper(I) complex is used for the hydrosilylation reaction of ketones.

[0015] Compared with the existing catalysts, the present invention has the following advantages:

[0016] 1. High yield and simple synthesis: The synthesis yield of the iminophosphine copper(I) complex is mostly not less than 70%, the synthesis process is simple, the product is easy to carry out single crystal cultivation, which is convenient for structure characterization and optimization.

[0017] 2. High catalytic performance: Under mild reaction conditions, the iminophosphine ligand copper(I) complex shows good catalytic activity for the hydrosilylation reduction reaction of acetophenone.

[0018] 3. Have the advantages of low cost and environmental friendliness: Copper is rich as a non-precious metal resource. Compared with precious metal catalysts (such as Ru, Rh, Ir, etc.), the catalytic cost is significantly reduced, and the feasibility of industrial application is improved. Moreover, the use of copper-based catalysts and hydride donors (PMHS) not only improves the catalytic efficiency but also reduces environmental pollution, meeting the concept of green chemistry. Description of the Drawings

[0019] Figure 1 It is the synthesis route diagram of iminophosphine copper(I) complex

[0020] Figure 2 It is the crystal structure diagram of copper complex 1 synthesized in Example 1 (for easy observation, non-special H atoms have been omitted);

[0021] Figure 3 It is the 1H NMR spectrum of copper complex 1 synthesized in Example 1;

[0022] Figure 4 It is the 31P NMR spectrum of copper complex 1 synthesized in Example 1;

[0023] Figure 5 It is the IR spectrum of copper complex 1 synthesized in Example 1;

[0024] Figure 6 It is the crystal structure diagram of copper complex 2 synthesized in Example 2 (for easy observation, non-special H atoms have been omitted);

[0025] Figure 7 It is the 1H NMR spectrum of copper complex 2 synthesized in Example 2;

[0026] Figure 8 It is the 31P NMR spectrum of copper complex 2 synthesized in Example 2;

[0027] Figure 9 It is the IR spectrum of copper complex 2 synthesized in Example 2;

[0028] Figure 10 It is the crystal structure diagram of copper complex 3 synthesized in Example 3 (for easy observation, non-special H atoms have been omitted);

[0029] Figure 11 It is the 1H NMR spectrum of copper complex 3 synthesized in Example 3;

[0030] Figure 12 It is the 31P NMR spectrum of copper complex 3 synthesized in Example 3;

[0031] Figure 13 It is the IR spectrum of copper complex 3 synthesized in Example 3;

[0032] Figure 14 Crystal structure diagram of copper complex 4 synthesized in Example 4 (for easy observation, non-special H atoms have been omitted);

[0033] Figure 15 1H NMR spectrum of copper complex 4 synthesized in Example 4;

[0034] Figure 16 31P NMR spectrum of copper complex 4 synthesized in Example 4;

[0035] Figure 17 IR spectrum of copper complex 4 synthesized in Example 4. Detailed implementation manners

[0036] The present invention will be further described below in conjunction with examples, but the protection scope of the present invention is not limited thereto.

[0037] The substrate raw materials, solvents, etc. involved in the following examples are all commercially available products. Without further explanation, the commercially available reagents used do not need to be further purified. Among them, phenyl iminophosphine ligands (SCRIVANTI A, MATTEOLI U, BEGHETTO V, et al. Iminophosphine–palladium(0) complexes as catalysts for the Stille reaction [J]. Tetrahedron, 2002, 58(34): 6881-6886.) alkyl iminophosphine ligands (YANG H, DU J, WANG C-L, et al. Synthesis, structures, characterizations and catalytic behaviors for hydrogen evolution of copper(II) and copper(I) complexes supported by diiminodiphosphines [J]. Inorganic Chemistry Communications, 2021, 130: 108719.) are synthesized according to the methods reported in the references, [Cu(MeCN) 4 BF 4(HATHAWAY B-J, HOLAH D-G, POSTLETHWAITE J-D, et al. The preparation and properties of some tetrakis(methylcyanide)copper(I) complexes[J]. Journal of the Chemical Society(Resumed), 1961: 3215-3218.) It has been synthesized by the reported method.

[0038] 1 HNMR(400 MHz) uses (CD 3 ) 2 SO / CDCl 3 as the solvent and TMS as the internal standard.

[0039] The multiplicities are defined as follows: s (singlet); d (doublet); t (triplet); q (quartet) and m (multiplet). The absorption intensities are defined as follows: s (strong absorption); m (medium absorption); w (weak absorption); vs (very strong absorption); vw (very weak absorption).

[0040] Unless otherwise defined, all technical terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of the present invention.

[0041] Example 1

[0042] Preparation of imino-phosphine ligand copper(I) complex 1

[0043] Target product:

[0044] (1) Dissolve imino-amine-phosphine ligand N,N'-[o-(diphenylphosphino)benzylidene]-4-benzoic acid amide (0.819 g, 2 mmol) and [Cu(MeCN) 4 BF 4 (0.315 g, 1 mmol) in a dichloromethane / acetonitrile (1 / 1) mixed solvent and react overnight at room temperature.

[0045] (2) Recrystallize and purify to obtain a red powder (0.8912 g, 0.92 mmol, 92%), which is complex 1.

[0046] (3) Dissolve the powder in dichloromethane, add n-hexane, and let it stand at room temperature. Red block crystals (complex 1) for single crystal X-ray diffraction characterization are obtained by liquid phase diffusion. The crystal is a triclinic system with the space group P-1. The main data of the crystal are as follows: α = 100.767(6)°, β = 106.149(5)°, γ = 107.972(5)°, The relevant crystallographic diagrams are as Figure 2 shown.

[0047] Figure 3 1 HNMR(400 MHz, DMSO-d 6 , ppm): δ = 12.92 (s, 2H, COOH), 8.65 (s, 2H, HC=N), 7.93 (d, J = 7.5 Hz, 2H, Ar-H), 7.75–7.44 (m, 12H, Ar / Ph-H), 7.28 (d, J = 7.8 Hz, 8H, Ar / Ph-H), 6.99 (d, J = 22.7 Hz, 10H, Ar / Ph-H), 6.83 (d, J = 8.1 Hz, 4H, Ar / Ph-H).

[0048] Figure 4 31 PNMR(162 MHz, DMSO-d6, ppm): δ = -9.14.

[0049] Figure 5 FT-IR(KBr, cm -1 ): 1693 (m, C=O), 1597 (m, C=N), 750, 698 (s, PPh 2 ).

[0050] Example 2

[0051] Preparation of Imino Phosphine Ligand Copper(I) Complex 2

[0052] Target product:

[0053] (1) Dissolve iminoamine phosphine ligand N,N'-[o-(diphenylphosphino)benzylidene]-4-(methoxy)aniline (0.798 g, 2 mmol) and [Cu(MeCN) 4 BF 4 (0.315 g, 1 mmol) in a dichloromethane / acetonitrile (1 / 1) mixed solvent and react overnight at room temperature.

[0054] (2) Recrystallize and purify to obtain a reddish-brown powder (0.8094 g, 0.86 mmol, 86%), which is Complex 2.

[0055] (3) Dissolve the powder in dichloromethane, add n-hexane, and let it stand at room temperature. Red block crystals (Complex 2) suitable for single crystal X-ray diffraction characterization are obtained through liquid phase diffusion. The crystal belongs to the monoclinic system with the space group of P2 1 / n, and the main data of the crystal are as follows: α = 90, β = 91.051(6)°, γ = 90, The relevant crystallographic diagrams are as Figure 6 shown.

[0056] Figure 7 1 H NMR (400 MHz, CDCl 3 , ppm): δ = 8.29 (s, 2H, HC=N), 7.71 (d, J = 7.6 Hz, 2H, Ar-H), 7.64 (td, J = 7.5, 1.3 Hz, 2H, Ar / Ph-H), 7.48 - 7.37 (m, 6H, Ar / Ph-H), 7.22 (s, H, Ar / Ph-H), 7.02 - 6.94 (m, 12H, Ar / Ph-H), 6.64 (d, J = 8.2 Hz, 4H, Ar / Ph-H), 6.51 (d, J = 8.3 Hz, 4H, Ar / Ph-H), 3.71 (s, 6H, CH 3 ).

[0057] Figure 8 31 P NMR (162 MHz, CDCl 3 , ppm): δ = -8.22.

[0058] Figure 9 FT-IR (KBr, cm -1 ): 1248 (s, C-O), 754, 696 (s, PPh 2 ).

[0059] Example 3

[0060] Preparation of Imino Phosphine Ligand Copper(I) Complex 3

[0061] Target product:

[0062] (1) Dissolve iminoamine phosphine ligand N,N'-[o-(diphenylphosphino)benzylidene]ethylenediamine (0.609 g, 1 mmol) and [Cu(MeCN) 4 BF 4 (0.315 g, 1 mmol) in a dichloromethane / acetonitrile (1 / 1) mixed solvent, and react overnight at room temperature.

[0063] (2) Recrystallization and purification gave an orange-yellow powder (0.5663 g, 0.75 mmol, 75%), namely complex 3.

[0064] (3) The powder was dissolved in dichloromethane, and n-hexane was used as the poor solvent. Orange-yellow block crystals (complex 3) suitable for single-crystal X-ray diffraction characterization were obtained by vapor diffusion. The crystal belongs to the triclinic system of space group P-1, and the main data of the crystal are as follows: α = 94.842(5)°, β = 93.630(6)°, γ = 98.285(5)°, The relevant crystallographic diagrams are as Figure 10 shown.

[0065] Figure 11 1 H NMR (400 MHz, CDCl 3 , ppm): δ = 8.65 (s, 2H, HC=N), 7.76 (d, J = 1.9 Hz, 2H, Ar-H), 7.63–7.56 (m, 2H, Ar / Ph-H), 7.47 (t, J = 7.4 Hz, 4H, Ar / Ph-H), 7.42–7.32 (m, 10H, Ar / Ph-H), 7.13 (q, J = 6.1 Hz, 8H, Ar / Ph-H), 7.05–6.97 (m, 2H, Ar / Ph-H), 3.70 (s, 4H, CH 2 ).

[0066] Figure 12 31 P NMR (162 MHz, CDCl 3 , ppm): δ = -2.49.

[0067] Figure 13 FT-IR (KBr, cm -1 ): 748, 696 (s, PPh 2 ).

[0068] Example 4

[0069] Preparation of Imino-Phosphine Ligand Copper(I) Complex 4

[0070] Target product:

[0071] (1) N,N'-[o-(Diphenylphosphino)benzylidene]-1,4-butanediamine (0.633 g, 1 mmol) of imino-amine-phosphine ligand was combined with [Cu(MeCN) 4 BF 4(0.315 g, 1 mmol) was dissolved in a dichloromethane / acetonitrile (1 / 1) mixed solvent and reacted overnight at room temperature.

[0072] (2) Recrystallization and purification gave a yellow powder (0.5482 g, 0.70 mmol, 70%), namely complex 4.

[0073] (3) The powder was dissolved in dichloromethane, and diethyl ether was added. Yellow block crystals (complex 4) suitable for single crystal X-ray diffraction characterization were obtained by liquid phase diffusion at room temperature. The crystal belongs to the triclinic system with the space group P-1, and the main data of the crystal are as follows: α = 92.298(5)°, β = 90.989(6)°, γ = 116.367(5)°, The relevant crystallographic diagrams are as Figure 14 shown.

[0074] Figure 15 1 1H NMR (400 MHz, CDCl 3 , ppm): δ = 8.61 (s, 2H, HC=N), 7.84 (d, J = 3.9 Hz, 2H, Ar-H), 7.65 (d, J = 13.9 Hz, 2H, Ar / Ph-H), 3.46 (s, 2H, Ar / Ph-H), 7.38 (s, 8H, Ar / Ph-H), 7.13 (d, J = 35.6 Hz, 14H, Ar / Ph-H), 7.05–6.97 (m, 2H, Ar / Ph-H), 3.53 (s, 4H, CH 2 ), 1.70 (s, 2H, CH 2 ), 1.22 (s, 2H, CH 2 ).

[0075] Figure 16 31 31P NMR (162 MHz, CDCl 3 , ppm): δ = -6.59.

[0076] Figure 17 FT-IR (KBr, cm -1 ): 750, 696 (s, PPh 2 ).

[0077] Example 5

[0078] The hydro-silylation reduction reaction of acetophenone catalyzed by an imino-phosphine ligand copper(I) complex to synthesize phenethyl alcohol:

[0079] First, weigh the complex (0.01 mmol) and potassium tert-butoxide (0.0056 g, 0.05 mmol) using an electronic balance and place them in a Schlenk reaction flask. Evacuate and refill with gas three times, and then replenish the flask with sufficient inert gas. Subsequently, add 3 mL of toluene solvent, stir at 25 °C for 15 min. After complete dissolution, add polymethylhydrosiloxane (PMHS, 1.5 mmol, 0.09 mL), stir well for 15 min, and finally add the substrate acetophenone (0.5 mmol). After the reaction for the set time, add 1 mL of methanol to the reaction flask for quenching, and then add 3 mL of 10% sodium hydroxide solution for hydrolysis. Stir for 3 h to fully hydrolyze the reaction solution. Separate the liquid, filter, and dry to obtain the organic liquid, and analyze the conversion rate of the catalytic reaction by gas chromatography.

[0080] The yield of phenethyl alcohol catalyzed by Complex 1 is 59%.

[0081] The yield of phenethyl alcohol catalyzed by Complex 2 is 86%.

[0082] The yield of phenethyl alcohol catalyzed by Complex 3 is 99%.

[0083] The yield of phenethyl alcohol catalyzed by Complex 1 is 71%.

Claims

1. Four novel amine phosphine ligand copper (I) complexes, characterized in that: Having any one of the following structures:

2. A method for synthesizing the novel iminophosphine ligand copper (I) complex as claimed in claim 1, characterized in that: The synthesis route is as follows: dissolve the iminophosphine ligand N,N'-[o-(diphenylphosphino)benzylidene]-4-benzoic acid amine and the copper salt [Cu(MeCN)4]BF4 in a dichloromethane / acetonitrile mixed solution, stir and react at room temperature, and after treatment, obtain the iminophosphine ligand copper (I) complex of structure 1.

3. A method for synthesizing the novel iminophosphine ligand copper (I) complex as claimed in claim 1, characterized in that: The synthesis route is as follows: dissolve the iminophosphine ligand N,N'-[o-(diphenylphosphino)benzylidene]-4-(methoxy)aniline and the copper salt [Cu(MeCN)4]BF4 in a dichloromethane / acetonitrile mixed solution, stir and react at room temperature, and after treatment, obtain the iminophosphine ligand copper (I) complex of structure 2.

4. A method for synthesizing the novel iminophosphine ligand copper (I) complex as claimed in claim 1, characterized in that: The synthesis route is as follows: dissolve the iminophosphine ligand N,N'-bis[o-(diphenylphosphino)benzylidene]ethylenediamine and the copper salt [Cu(MeCN)4]BF4 in a dichloromethane / acetonitrile mixed solution, stir and react at room temperature, and after treatment, obtain the iminophosphine ligand copper (I) complex of structure 3.

5. A method for synthesizing the novel iminophosphine ligand copper (I) complex as claimed in claim 1, characterized in that: The synthesis route is as follows: the iminophosphine ligand N,N'-bis[o-(diphenylphosphino)benzylidene]-1,4-butanediamine and the copper salt [Cu(MeCN)4]BF4 are dissolved in a dichloromethane / acetonitrile mixed solution, stirred for reaction at room temperature, and after treatment, the iminophosphine ligand copper (I) complex of structure 4 is obtained.

6. Use of the novel iminophosphine ligand copper (I) complex according to claim 1 as a catalyst for the hydrosilylation reaction of ketones.

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