Silicon-containing polyphosphine ligand with cross structure as well as preparation method and application of silicon-containing polyphosphine ligand

Abstract

The invention discloses a silicon-containing polyphosphine ligand with a cross structure and a preparation method and application thereof, the silicon-containing polyphosphine ligand provided by the invention has a structural general formula as shown in formula (I), R1 and R2 are independently selected from C1-C12 alkyl, phenyl, substituted phenyl or benzyl, R3 and R4 are independently selected from any one of alkyl, alkoxy and halogen, and n is selected from an integer of 1-3. The invention also provides a preparation method of the silicon-containing polyphosphine ligand with the cross configuration, which comprises the following steps: in a protective atmosphere, using a reaction system containing siloxane, a phosphine hydrogen compound, a free radical initiator and a solvent, and reacting at 70-120 DEG C for 5-15 t to prepare the silicon-containing polyphosphine ligand with the cross configuration. The compound is proved to play a good role in long carbon chain hydroformylation reaction and has excellent selectivity. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the technical field of organic chemistry, and particularly relates to a silicon-containing polyphosphine ligand with a cross-shaped structure, a preparation method thereof, and an application thereof. Background Art

[0002] With the development of technology, organosilicon compounds and materials are widely used in the fields of organic synthesis, medicine, and high-tech materials. Multidentate phosphine ligands have excellent coordination properties. Because they have multiple coordination sites and are more likely to form coordination with metals, they affect the catalytic performance of metal catalysts, and the obtained products can also have extensive application values in medicine, catalysis, and photoreaction.

[0003] Siloxane is an organic compound composed of silicon and oxygen. Due to its unique properties, it is widely used in various industries such as building materials, cosmetics, lubricants, and electronic products, and is also an important precursor for various polymer reactions. Phosphine ligands are the preferred ligands for various reactions because of their special chemical properties and their ability to change the coordination mode with metals through valence changes. By screening different phosphine ligands, the electronic properties and steric hindrance of the metal center can be regulated, thereby achieving the performance of improving the stability of catalytic reactions.

[0004] In 2006, Xumu Zhang et al. designed a tetraphosphine ligand and applied it to the hydroformylation reaction of olefins. However, the synthesis of its ligand requires multiple steps and is difficult. In recent years, no one has still overcome its cumbersome synthesis process and successfully combined the excellent properties of siloxane and phosphine ligands. Summary of the Invention

[0005] The first object of the present invention is to provide a silicon-containing polyphosphine ligand with a cross-shaped structure in view of the deficiencies in the prior art. The structure of the present invention has 4 phosphorus atoms as phosphine ligands, and there are 4 reaction sites that can coordinate with metals in the reaction, greatly increasing the probability of coordinating with metals, so that the present invention has a very broad application prospect in the field of metal catalysis.

[0006] The present invention is achieved by the following technical solutions:

[0007] A silicon-containing polyphosphine ligand with a cross-shaped structure has a structure shown in formula (I):

[0008]

[0009]

[0010] Wherein R 1 , R 2 are each independently selected from C1-C 12 alkyl, phenyl, Any one of benzyl; the C1-C 12 The alkyl group is selected from any one of methyl, ethyl, propyl, butyl, tert-butyl, isopropyl, cyclopentyl, cyclohexyl, cycloheptyl, octyl; R 3 , R 4 Each independently is selected from any one of an alkyl group, an alkoxy group, and a halogen, and n is selected from the integer 1-3.

[0011] The second object of the present invention is to provide a preparation method of the silicon-containing polyphosphine ligand of the above cross-frame structure, including the following steps:

[0012] In a protective atmosphere, the siloxane shown in formula (II), the phosphine hydride shown in formula (III), and the radical initiator are mixed with a solvent in a molar ratio of 1:(4-6):(0.01-0.5), and reacted at 70-120 °C for 5-15 days to obtain a multi-tooth phosphine ligand containing a silane skeleton. The reaction formula is as follows:

[0013]

[0014] Preferably, the siloxane is selected from any one of tetrakis(dimethylethenylsiloxy)silane, tetrakis(dimethylallylsiloxy)silane, and tetrakis(dimethylbutenylsiloxy)silane.

[0015] Preferably, the specific structure of the phosphine hydride is any one of the following (a) to (r).

[0016]

[0017] Preferably, the radical initiator is selected from one or two of azobisisobutyronitrile and azobisisoheptanenitrile.

[0018] Preferably, the solvent is selected from one of tetrahydrofuran, toluene, 1,4-dioxane, N,N-dimethylformamide, and nitrile compounds. The protective atmosphere is an inert gas, preferably nitrogen.

[0019] Preferably, after the reaction is completed, the obtained mixture is separated and vacuum dried.

[0020] The third object of the present invention is to provide the use of the above-mentioned silicon-containing polyphosphine ligand of the cross-frame structure in metal-catalyzed reactions.

[0021] Compared with the prior art, the advantages of the present invention are as follows:

[0022] The preparation method of the cross-frame structure silicon-containing polyphosphine ligand prepared by the present invention is simple, the raw materials are easy to obtain, and the diversity preparation of the cross-frame structure silicon-containing polyphosphine ligand can be realized.

[0023] The silicon-containing polyphosphine ligand with a cross-shaped structure prepared by the present invention has good stability and high-temperature stability. It can be used as a multidentate phosphine ligand for metal-catalyzed reactions in the hydroformylation of long-chain olefins. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 1H NMR spectrum of the silicon-containing polyphosphine ligand with a cross-shaped structure prepared in Example 1 of the present invention.

[0025] Figure 2 13C NMR spectrum of the silicon-containing polyphosphine ligand with a cross-shaped structure prepared in Example 1 of the present invention.

[0026] Figure 3 31P NMR spectrum of the silicon-containing polyphosphine ligand with a cross-shaped structure prepared in Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] The synthesis scheme of the present invention will be further described below in conjunction with examples and drawings. The examples of the present invention are implemented on the premise of the technical solution of the invention, and detailed synthesis steps and specific operation methods are given. However, the protection scope of the present invention is not limited to the following examples.

[0028] As described above, due to technical deficiencies, the inventors of this solution have carried out a large amount of research and practice before they were able to propose this invention. The invention mainly constructs a phosphine ligand by a one-pot method using a cross-shaped siloxane and a phosphine hydride under the action of a radical initiator, with high yield and stable chemical properties, and has industrial application prospects.

[0029] In the following examples, the experimental reagents used, unless otherwise specified, can be purchased from conventional biochemical reagent companies.

[0030] Example 1:

[0031] Under the protection of nitrogen gas, AIBN (0.9 mmol) was added to a three-necked flask, and then 12 ml of toluene was added to dissolve the radical initiator. Then, tetrakis(dimethylethenylsiloxy)silane (20 mmol) and diphenylphosphine hydride (88 mmol) were added to the flask and reacted at 80 °C for 12 days. After that, the product was separated by column chromatography and dried under vacuum to obtain a colorless viscous product A with a yield of 75%.

[0032]

[0033] The 1H NMR spectrum of the silicon-containing polyphosphine ligand with a cross-shaped structure prepared in this example is as shown in Figure 1 as shown, the 13C NMR spectrum is as shown in Figure 2 as shown, and the 31P NMR spectrum is as shown in Figure 3 as shown.

[0034] 1HNMR (400 MHz, CDCl3) δ 7.51–7.41 (m, 16H), 7.36 (d, J = 4.7 Hz, 24H), 2.10–1.98 (m, 8H), 0.71–0.59 (m, 8H), 0.08 (s, 24H). 13 CNMR (101 MHz, CDCl3) δ 139.01 (d, J = 14.3 Hz), 132.97 (d, J = 18.0 Hz), 128.87–128.47 (m), 21.08 (d, J = 13.9 Hz), 13.68 (d, J = 10.1 Hz), -0.00 (s). 31 PNMR (162 MHz, CDCl3) δ -8.91– -9.79 (m).

[0035] Example 2:

[0036] Under the protection of nitrogen gas, (1 mmol) of AIBN was added to a three-necked flask, and then 12 ml of toluene was added to dissolve the radical initiator. Then, tetrakis(dimethylethenylsiloxy)silane (20 mmol) and dicyclohexylphosphine hydride (88 mmol) were added to the flask and reacted at 80 °C for 15 days. After that, it was separated by column chromatography and dried under vacuum to obtain a colorless viscous product B with a yield of 80%. 31 PNMR (162 MHz, CDCl3) δ -9.75 (m).

[0037]

[0038] Example 3:

[0039] Under the protection of nitrogen gas, (1.4 mmol) of AIBN was added to a three-necked flask, and then 15 ml of toluene was added to dissolve the radical initiator. Then, tetrakis(dimethylethenylsiloxy)silane (20 mmol) and di-tert-butylphosphine hydride (88 mmol) were added to the flask and reacted at 80 °C for 8 days. After that, it was separated by column chromatography and dried under vacuum to obtain a colorless viscous product C with a yield of 60%. 31 PNMR (162 MHz, CDCl3) δ -9.58– -9.84 (m).

[0040]

[0041] Example 4:

[0042] Under the protection of nitrogen gas, (0.9 mmol) of AIBN was added to a three-necked flask, and then 20 ml of toluene was added to dissolve the radical initiator. Subsequently, tetrakis(dimethylethenylsiloxy)silane (20 mmol) and dicyclopentylphosphine hydride (88 mmol) were added to the flask, and the reaction was carried out at 80 °C for 12 days. Then, the product was separated by column chromatography and dried under vacuum to obtain a colorless viscous product D with a yield of 78%. 31 PNMR (162 MHz, CDCl3) δ -9.53–-9.80 (m).

[0043]

[0044] Example 5:

[0045] Under the protection of nitrogen gas, (2 mmol) of AIBN was added to a three-necked flask, and then 20 ml of toluene was added to dissolve the radical initiator. Subsequently, tetrakis(dimethylethenylsiloxy)silane (20 mmol) and dibutylphosphine hydride (88 mmol) were added to the flask, and the reaction was carried out at 80 °C for 10 days. Then, the product was separated by column chromatography and dried under vacuum to obtain a colorless viscous product E with a yield of 52%. 31 PNMR (162 MHz, CDCl3) δ -9.63–-9.90 (m).

[0046]

[0047] Example 6:

[0048] Under the protection of nitrogen gas, (2 mmol) of AIBN was added to a three-necked flask, and then 20 ml of toluene was added to dissolve the radical initiator. Subsequently, tetrakis(dimethylethenylsiloxy)silane (20 mmol) and 9-phosphabicyclo[4.2.1]nonane (88 mmol) were added to the flask, and the reaction was carried out at 120 °C for 15 days. Then, the product was separated by column chromatography and dried under vacuum to obtain a colorless viscous product F with a yield of 39%. 31 PNMR (162 MHz, CDCl3) δ -8.86–-9.83 (m).

[0049]

[0050] Example 7:

[0051] Under the protection of nitrogen gas, (1 mmol) of AIBN was added to a three-necked flask, and then 15 ml of toluene was added to dissolve the radical initiator. Subsequently, tetrakis(dimethylethenylsiloxy)silane (20 mmol) and di-p-xylene phosphonium chloride (88 mmol) were added to the flask, and the reaction was carried out at 90 °C for 10 days. Then, the product was separated by column chromatography and dried under vacuum to obtain a colorless viscous product G with a yield of 75%. 31PNMR (162 MHz, CDCl3) δ -8.97–-9.88 (m).

[0052]

[0053] Example 8:

[0054] Under the protection of nitrogen gas, after adding AIBN (1 mmol) into a three-necked flask, 15 ml of toluene was added to dissolve the radical initiator. Then, tetrakis(dimethylvinyloxysilyl)silane (20 mmol) and bis(o-tolyl)phosphine (100 mmol) were added to the flask and reacted at 90 °C for 10 days. After that, it was separated by column chromatography and dried under vacuum to obtain a colorless viscous product H with a yield of 60%. 31 PNMR (162 MHz, CDCl3) δ -8.97–-9.84 (m)

[0055]

[0056] Example 9:

[0057] Under the protection of nitrogen gas, after adding AIBN (1 mmol) into a three-necked flask, 15 ml of toluene was added to dissolve the radical initiator. Then, tetrakis(dimethylvinyloxysilyl)silane (20 mmol) and bis(4-chlorophenyl)phosphine (100 mmol) were added to the flask and reacted at 80 °C for 12 days. After that, it was separated by column chromatography and dried under vacuum to obtain a colorless viscous product I with a yield of 55%. 31 PNMR (162 MHz, CDCl3) δ -9.37–-9.85 (m)

[0058]

[0059] Example 10:

[0060] Under the protection of nitrogen gas, after adding AIBN (1 mmol) into a three-necked flask, 20 ml of toluene was added to dissolve the radical initiator. Then, tetrakis(dimethylvinyloxysilyl)silane (20 mmol) and bis(4-methoxyphenyl)phosphine (110 mmol) were added to the flask and reacted at 90 °C for 12 days. After that, it was separated by column chromatography and dried under vacuum to obtain a colorless viscous product J with a yield of 66%. 31 PNMR (162 MHz, CDCl3) δ -8.89–-9.64 (m)

[0061]

[0062] Example 11:

[0063] Under the protection of nitrogen gas, (0.9 mmol) of AIBN was added to a three-necked flask, and then 12 ml of toluene was added to dissolve the radical initiator. Then, tetrakis(dimethylallylsiloxy)silane (20 mmol) and diphenylphosphine hydride (88 mmol) were added to the flask, and the reaction was carried out at 100 °C for 12 days. After that, it was separated by column chromatography and dried under vacuum to obtain a colorless viscous product K with a yield of 73%. 31 PNMR (162 MHz, CDCl3) δ -8.96–-9.79 (m).

[0064]

[0065] Example 12:

[0066] Under the protection of nitrogen gas, (0.9 mmol) of AIBN was added to a three-necked flask, and then 12 ml of toluene was added to dissolve the radical initiator. Then, tetrakis(dimethylbutenylsiloxy)silane (20 mmol) and diphenylphosphine hydride (100 mmol) were added to the flask, and the reaction was carried out at 120 °C for 12 days. After that, it was separated by column chromatography and dried under vacuum to obtain a colorless viscous product L with a yield of 66%. 31 PNMR (162 MHz, CDCl3) δ -9.17–-9.79 (m).

[0067]

[0068] Example 13:

[0069] Under the protection of nitrogen gas, (4 mmol) of AIBN was added to a three-necked flask, and then 12 ml of toluene was added to dissolve the radical initiator. Then, tetrakis(dimethylethenylsiloxy)silane (20 mmol) and diphenylphosphine hydride (100 mmol) were added to the flask, and the reaction was carried out at 80 °C for 10 days. After that, it was separated by column chromatography and dried under vacuum to obtain a colorless viscous product M with a yield of 69%. 31 PNMR (162 MHz, CDCl3) δ -9.10–-9.75 (m).

[0070]

[0071] Example 14:

[0072] Under the protection of nitrogen gas, (4 mmol) of AIBN was added to a three-necked flask, and then 12 ml of toluene was added to dissolve the radical initiator. Then, tetrakis(dimethylethenylsiloxy)silane (20 mmol) and diphenylphosphine hydride (100 mmol) were added to the flask, and the reaction was carried out at 100 °C for 6 days. After that, it was separated by column chromatography and dried under vacuum to obtain a colorless viscous product N with a yield of 69%. 31PNMR (162 MHz, CDCl3) δ -9.12–-9.88 (m).

[0073]

[0074] Example 15:

[0075] Under the protection of nitrogen gas, (1.5 mmol) of AIBN was added to a three-necked flask, and then 20 ml of toluene was added to dissolve the radical initiator. Then, tetrakis(dimethylallylsilyloxy)silane (20 mmol) and di-tert-butylphosphine hydride (88 mmol) were added to the flask and reacted at 90 °C for 12 days. After that, it was separated by column chromatography and dried under vacuum to obtain a colorless viscous product O with a yield of 53%. 31 PNMR (162 MHz, CDCl3) δ -9.34–-9.94 (m).

[0076]

[0077] Example 16:

[0078] Under the protection of nitrogen gas, (2 mmol) of AIBN was added to a three-necked flask, and then 20 ml of toluene was added to dissolve the radical initiator. Then, tetrakis(dimethylallylsilyloxy)silane (20 mmol) and di-tert-butylphosphine hydride (90 mmol) were added to the flask and reacted at 90 °C for 12 days. After that, it was separated by column chromatography and dried under vacuum to obtain a colorless viscous product P with a yield of 50%. 31 PNMR (162 MHz, CDCl3) δ -9.42–-9.84 (m).

[0079]

[0080] Example 17:

[0081] Under the protection of nitrogen gas, (1 mmol) of AIBN was added to a three-necked flask, and then 20 ml of toluene was added to dissolve the radical initiator. Then, tetrakis(dimethylallylsilyloxy)silane (20 mmol) and dicyclopentylphosphine hydride (90 mmol) were added to the flask and reacted at 90 °C for 15 days. After that, it was separated by column chromatography and dried under vacuum to obtain a colorless viscous product Q with a yield of 70%. 31 PNMR (162 MHz, CDCl3) δ -9.52–-9.86 (m).

[0082]

[0083] Example 18:

[0084] Under the protection of nitrogen gas, (1 mmol) of AIBN was added to a three-necked flask, and then 20 ml of toluene was added to dissolve the radical initiator. Subsequently, tetrakis(dimethylallylsiloxy)silane (20 mmol) and dicyclopentylphosphine hydride (95 mmol) were added to the flask, and the reaction was carried out at 90 °C for 15 days. Then, the product was separated by column chromatography and dried under vacuum to obtain a colorless viscous product R with a yield of 65%. 31 PNMR (162 MHz, CDCl3) δ -9.33–-9.91 (m).

[0085]

[0086] Example 19:

[0087] Under the protection of nitrogen gas, (1.5 mmol) of AIBN was added to a three-necked flask, and then 20 ml of toluene was added to dissolve the radical initiator. Subsequently, tetrakis(dimethylallylsiloxy)silane (20 mmol) and bis(4-methoxyphenyl)phosphine (110 mmol) were added to the flask, and the reaction was carried out at 100 °C for 15 days. Then, the product was separated by column chromatography and dried under vacuum to obtain a colorless viscous product S with a yield of 60%. 31 PNMR (162 MHz, CDCl3) δ -8.87–-9.75 (m)

[0088]

[0089] Example 20:

[0090] Under the protection of nitrogen gas, (1.5 mmol) of AIBN was added to a three-necked flask, and then 20 ml of toluene was added to dissolve the radical initiator. Subsequently, tetrakis(dimethylallylsiloxy)silane (20 mmol) and bis(4-methoxyphenyl)phosphine (110 mmol) were added to the flask, and the reaction was carried out at 120 °C for 15 days. Then, the product was separated by column chromatography and dried under vacuum to obtain a colorless viscous product T with a yield of 54%. 31 PNMR (162 MHz, CDCl3) δ -8.77–-9.8988 (m)

[0091]

[0092] Application Example:

[0093] The silicon-containing polyphosphine ligand obtained in Example 1 was applied to the hydroformylation reaction of 1-octene and compared with other common polyphosphine ligands. The following are the specific reaction data and reaction routes.

[0094]

[0095] Table 1 Comparison of Catalytic Performance of Different Phosphorus Ligands in the Hydroformylation of 1-Octylamine

[0096]

[0097]

[0098]

[0099] As can be seen from Table 1, the yield, selectivity, and conversion rate of L9 (i.e., the silicon-containing polyphosphorus ligand provided by the present invention) are all relatively high, and it has broad application prospects in metal-catalyzed reactions.

[0100] The above embodiments are the basic principles, main features, and advantages of the present invention, which only illustrate the technical aspects of the present invention, rather than a limitation on the protection scope of the present invention. Some improvements made based on the above embodiments are all within the protection scope of the present invention.

Claims

1. A cross-shaped silicon-containing polyphosphine ligand, characterized in that: Having a structure as shown in formula (I): Where R 1 , R 2 Each independently selected from C1-C 12 Alkyl, phenyl, or one of the benzyl groups, R 3 , R 4 Each is independently selected from one of alkyl, alkoxy or halogen, and n is selected from an integer of 1-3.

2. The cross-shaped silicon-containing polyphosphine ligand according to claim 1, characterized in that: C1-C 12 The alkyl group is selected from any one of methyl, ethyl, propyl, butyl, tert-butyl, isopropyl, cyclopentyl, cyclohexyl, cycloheptyl or octyl.

3. A method for preparing a cross-shaped silicon-containing polyphosphine ligand according to any one of claims 1 to 2, characterized in that: The preparation method comprises the following steps: In a protective atmosphere, the siloxane represented by formula (II), the phosphine hydrogen compound represented by formula (III) and the free radical initiator are mixed with a solvent in a molar ratio of 1: (4-6): (0.01-0.5), and reacted at 70-120° C. for 5-15 days to obtain a multidentate phosphine ligand containing a silane skeleton. The reaction formula is as follows:

4. The preparation method according to claim 3, characterized in that: The siloxane is selected from any one of tetrakis(dimethylvinylsiloxy)silane, tetrakis(dimethylacrylsiloxy)silane and tetrakis(dimethylbutylsiloxy)silane.

5. The preparation method according to claim 3, characterized in that: The specific structure of the phosphine hydrogen compound is any one of the following formulas (a) to (r):

6. The preparation method according to claim 3, characterized in that: The free radical initiator is selected from one or both of azobisisobutyronitrile and azobisisoheptanenitrile.

7. The preparation method according to claim 3, characterized in that: The solvent is selected from tetrahydrofuran, toluene, 1,4-dioxane, N,N-dimethylformamide, and nitrile compounds.

8. The preparation method according to claim 3, characterized in that: The protective atmosphere is any one of an inert gas and a nitrogen atmosphere.

9. The preparation method according to claim 3, characterized in that: The reaction step also includes: after the reaction is completed, separating and vacuum drying the obtained product.

10. Use of the cross-shaped silicon-containing polyphosphine ligand according to any one of claims 1 to 2 in a metal catalytic reaction.

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