Aza-carbene palladium complex and its preparation method and application

Abstract

The application discloses aza cyclo carbene palladium complex and a preparation method and application thereof, and the structure of the aza cyclo carbene palladium complex is shown as formula (I): formula (I); the aza cyclo carbene palladium complex can be used for catalyzing arylization of halogenated aromatic hydrocarbon, has the advantages of high yield, and the arylization homopolymer of the halogenated aromatic hydrocarbon prepared by catalysis has the characteristics of narrow distribution and low molecular weight.

Description

Technical Field

[0001] This invention belongs to the field of carbene palladium complex technology, and particularly relates to a nitrogen heterocyclic carbene palladium complex, its preparation method and application. Background Technology

[0002] Low molecular weight copolymers containing 3,4-ethylenedioxythiophene in their main chain not only possess excellent electronic properties but also exhibit high solubility in both polar and nonpolar organic solvents. When used to prepare thin films for organic light-emitting devices, they can maximize film strength and minimize damage from other substances. Therefore, low molecular weight copolymers containing 3,4-ethylenedioxythiophene in their main chain have wide applications in devices with electrosemiconductor properties.

[0003] Existing technologies generally use tetratetraphenylphosphine palladium as a catalyst to catalyze the preparation of low molecular weight copolymers containing 3,4-ethylenedioxythiophene in the main chain. However, using tetratetraphenylphosphine palladium as a catalyst makes it difficult to catalyze the arylation of haloaromatics, thus yielding arylated homopolymers of haloaromatics. Therefore, developing a catalyst for the preparation of low molecular weight copolymers with a narrow distribution and containing 3,4-ethylenedioxythiophene in the main chain has market value for isobutylene. Summary of the Invention

[0004] To address the shortcomings of the prior art, a nitrogen-heterocyclic carbene palladium complex is provided. This nitrogen-heterocyclic carbene palladium complex can be used to catalyze the arylation reaction of haloaromatics, and has the advantage of high yield. The arylation homopolymer of haloaromatics prepared by the catalysis has the characteristics of narrow distribution and low molecular weight.

[0005] The purpose of this invention is to provide a nitrogen-heterocyclic carbene palladium complex, the structure of which is shown in formula (I):

[0006]

[0007] Equation (Ⅰ)

[0008] R1, R2, and R3 are independently selected from H or C1~C6 alkyl groups, and X is selected from Cl or Br.

[0009] In some embodiments of the present invention, R1, R2 and R3 are independently selected from H or C1~C3 alkyl groups.

[0010] In some embodiments of the present invention, R1 or R2 is independently selected from methyl, ethyl or isopropyl, R3 is selected from H or methyl, and R1 is the same as R2.

[0011] Another object of the present invention is to provide a method for preparing the aforementioned nitrogen heterocyclic carbene palladium complex, comprising the following steps:

[0012] S1. Will replace aniline The compound was reacted with 4,7-di-tert-butylacenaphthoquinone in the presence of a catalyst and solvent, and purified to give a diimine compound.

[0013] S2. React the diimine compound with chloromethyl ethyl ether to obtain compound E;

[0014] S3. Compound E is reacted with palladium chloride and substituted pyridine. The reaction under the action of inorganic salts yields a nitrogen-containing heterocyclic carbene palladium complex.

[0015] In some embodiments of the present invention, in S1, the catalyst is selected from anhydrous zinc chloride.

[0016] In some embodiments of the present invention, in S1, the solvent is selected from glacial acetic acid.

[0017] In some embodiments of the present invention, in S1, the reaction temperature is 110~130°C and the time is 3~7h.

[0018] In some embodiments of the present invention, in S1, the molar ratio of the substituted aniline to 4,7-di-tert-butylacenaphthoquinone is 2 to 2.5:1.

[0019] In some embodiments of the present invention, in S1, the molar ratio of the catalyst to 4,7-di-tert-butylacenaphthoquinone is 2 to 2.5:1.

[0020] In some embodiments of the present invention, in S2, the molar ratio of the diimine compound to chloromethyl ethyl ether is 1:0.02~0.05.

[0021] In some embodiments of the present invention, in S2, the reaction temperature is 80~120°C and the time is 18~30h.

[0022] In some embodiments of the present invention, in S2, the reaction is carried out under an inert atmosphere.

[0023] In some embodiments of the present invention, in S3, the molar ratio of compound E to palladium chloride, substituted pyridine, and inorganic salt is 1:1~1.3:4~8:8~12.

[0024] In some embodiments of the present invention, in S3, the inorganic salt is selected from potassium carbonate.

[0025] In some embodiments of the present invention, in step S3, the reaction temperature is 40~80°C and the time is 6~10h.

[0026] Another object of the present invention is to provide the application of the aforementioned nitrogen heterocyclic carbene palladium complex or the nitrogen heterocyclic carbene palladium complex prepared by the aforementioned method in the catalytic arylation coupling reaction of haloaromatics.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The nitrogen heterocyclic carbene palladium complex of the present invention is used to catalyze the arylation reaction of haloaromatics, and has the advantage of high yield. The arylation homopolymer of haloaromatics prepared by catalysis has the characteristics of narrow distribution and low molecular weight.

[0029] (2) The method of preparing nitrogen heterocyclic carbene palladium complex of the present invention has mild reaction conditions and high yield. Attached Figure Description

[0030] Figure 1 The image shows the 1H NMR spectrum of the diimine compound D1 obtained in Example 1.

[0031] Figure 2 The image shows the carbon NMR spectrum of the diimine compound D1 obtained in Example 1.

[0032] Figure 3 The image shows the 1H NMR spectrum of the diimine compound D2 obtained in Example 2.

[0033] Figure 4 The image shows the carbon NMR spectrum of the diimine compound D2 obtained in Example 2.

[0034] Figure 5 The image shows the 1H NMR spectrum of the diimine compound D3 obtained in Example 3.

[0035] Figure 6 The image shows the carbon NMR spectrum of the diimine compound D3 obtained in Example 3.

[0036] Figure 7 The image shows the 1H NMR spectrum of compound E1 obtained in Example 4.

[0037] Figure 8 The image shows the carbon NMR spectrum of compound E1 obtained in Example 4.

[0038] Figure 9 The image shows the 1H NMR spectrum of compound E2 obtained in Example 5.

[0039] Figure 10 The image shows the carbon NMR spectrum of compound E2 obtained in Example 5.

[0040] Figure 11 The image shows the 1H NMR spectrum of compound E3 obtained in Example 6.

[0041] Figure 12 The image shows the carbon NMR spectrum of compound E3 obtained in Example 6.

[0042] Figure 13The image shows the 1H NMR spectrum of the nitrogen heterocyclic carbene palladium complex C1 obtained in Example 7.

[0043] Figure 14 The image shows the carbon NMR spectrum of the nitrogen heterocyclic carbene palladium complex C1 obtained in Example 7.

[0044] Figure 15 The image shows the 1H NMR spectrum of the nitrogen heterocyclic carbene palladium complex C2 prepared in Example 8.

[0045] Figure 16 The image shows the carbon NMR spectrum of the nitrogen heterocyclic carbene palladium complex C2 obtained in Example 8.

[0046] Figure 17 The image shows the 1H NMR spectrum of the nitrogen heterocyclic carbene palladium complex C3 obtained in Example 9.

[0047] Figure 18 The image shows the carbon NMR spectrum of the nitrogen heterocyclic carbene palladium complex C3 obtained in Example 9. Detailed Implementation

[0048] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0049] All raw materials used in this invention are commercially available.

[0050] The nitrogen-containing heterocyclic carbene palladium complexes in each embodiment were prepared via the following reaction route: Example

[0051] This embodiment provides a method for preparing a diimine compound D1, which specifically includes the following steps:

[0052] S1. 2,4,6-Trimethylaniline (4.4 mmol), 4,7-di-tert-butylacenaphthene (2 mmol), and anhydrous zinc chloride (4.6 mmol) were added sequentially to a 100 ml side-necked flask. 50 ml of glacial acetic acid was added as a solvent. The mixture was refluxed at 120 °C under N2 protection for 5 h. After the reaction was completed and cooled to room temperature, an orange-yellow solid was formed in the solution. The solution was filtered, and the filter cake was washed repeatedly with glacial acetic acid to remove unreacted raw materials. The solid obtained by filtration was dried and dissolved in dichloromethane. Zinc removal reaction was carried out with 100 mL of potassium oxalate aqueous solution (4.6 g / L). After stirring for 5 h, the white zinc salt was removed by filtration. The remaining organic layer was extracted in water multiple times, dried by rotary evaporation, and recrystallized with (dichloromethane / n-hexane) to obtain orange-yellow crystals, namely diimine compound D1, with a yield of 64%.

[0053] 1 H NMR (400 MHz, CDCl3) δ 7.79 (s, 2H), 7.01 (s, 4H), 6.64 (s, 2H), 2.38 (s, 6H), 2.10 (s, 12H), 1.16 (s, 18H).

[0054] 13 C NMR (101 MHz, CDCl3) δ 162.47, 151.73, 147.47, 137.65, 133.00,128.90, 125.24, 123.84, 121.14, 35.48, 31.66, 31.11, 20.91, 17.73. Example

[0055] This embodiment provides a method for preparing a diimine compound D2, which specifically includes the following steps:

[0056] The only difference from Example 1 is that 2,4,6-trimethylaniline is replaced with 2,6-diethylaniline. The other steps are the same as in Example 1, yielding an orange-yellow solid, namely diimine compound D2, with a yield of 62%.

[0057] 1 H NMR (400 MHz, CDCl3) δ 7.77 (d, J = 1.1 Hz, 2H), 7.25 – 7.20 (m,4H), 7.20 – 7.15 (m, 2H), 6.63 (d, J = 1.2 Hz, 2H), 2.53 (d, J = 42.4, 14.6,7.4 Hz, 8H), 1.14 (s, 18H), 1.08 (t, J = 7.6 Hz, 12H).

[0058] 13 C NMR (101 MHz, CDCl3) δ 162.19, 151.61, 149.13, 137.80, 131.34, 130.60, 129.14, 126.61, 124.20, 123.83, 121.90, 35.55, 31.15, 24.83, 14.30. Example

[0059] This embodiment provides a method for preparing a diimine compound D3, which specifically includes the following steps:

[0060] The only difference from Example 1 is that 2,4,6-trimethylaniline is replaced with 2,6-diisopropylaniline. The other steps are the same as in Example 1, yielding an orange-yellow solid, namely diimine compound D3, with a yield of 68%.

[0061] 1 H NMR (400 MHz, CDCl3) δ 7.74 (s, 2H), 7.25 (s, 6H), 6.54 (s, 2H), 3.02 (t, J = 13.7, 6.8 Hz, 4H), 1.21 (d, J = 6.8 Hz, 12H), 1.10 (s, 18H),0.91 (d, J = 6.9 Hz, 12H).

[0062] 13 C NMR (101 MHz, CDCl3) δ 162.26, 151.30, 147.94, 137.78, 135.82,130.52, 128.94, 124.37, 123.59, 122.29, 35.44, 31.00, 28.56, 23.51, 23.25. Example

[0063] This embodiment provides a method for preparing compound E1, specifically including the following steps:

[0064] Weigh 1.0 mmol of diimine compound D1 into a 25 ml stoppered bottle, add 3-4 ml of chloromethyl ether to dissolve it, purge the air from the bottle with N2 and seal it, react at 100 °C for 24 h, and after treatment, give compound E1 with a yield of 78%;

[0065] 1H NMR (400 MHz, CDCl3) δ 11.16 (s, 1H), 7.89 (d, J = 1.0 Hz, 2H), 7.27 (s, 2H), 7.14 (s, 4H), 2.42 (s, 6H), 2.30 (s, 12H), 1.34 (s, 18H).

[0066] 13 C NMR (101 MHz, CDCl3) δ 152.20, 142.02, 141.42, 136.94, 134.17,132.19, 130.26, 129.88, 129.65, 129.42, 127.77, 125.18, 123.24, 120.83,35.68, 31.45, 21.43, 18.04. Example

[0067] This embodiment provides a method for preparing compound E2, specifically including the following steps:

[0068] The only difference from Example 4 is that diimine compound D1 is replaced with diimine compound D2, and the other steps are the same as in Example 4, yielding compound E2 with a yield of 52%;

[0069] 1 H NMR (400 MHz, CDCl3) δ 11.31 (s, 1H), 7.89 (s, 2H), 7.60 (s, 2H), 7.41 (d, J = 6.9 Hz, 4H), 7.19 (s, 2H), 2.66 (d, J = 43.9 Hz, 8H), 1.30 (s,18H), 1.17 (s, 12H).

[0070] 13 C NMR (101 MHz, CDCl3) δ 152.23, 140.37, 137.54, 131.90, 131.23,129.50, 127.79, 125.25, 122.97, 121.01, 35.62, 31.34, 24.73, 14.78. Example

[0071] This embodiment provides a method for preparing compound E3, specifically including the following steps:

[0072] The only difference from Example 4 is that diimine compound D1 is replaced with diimine compound D3, and the other steps are the same as in Example 4, yielding compound E3 with a yield of 48%;

[0073] 1 H NMR (400 MHz, CDCl3) δ 11.19 (s, 1H), 7.92 (t, J = 2.9 Hz, 1H), 7.70 (dd, J = 14.5, 6.5 Hz, 1H), 7.48 (dd, J = 11.4, 5.2 Hz, 1H), 7.21 (t, J= 2.8 Hz, 1H), 2.70 (t, J = 13.1, 6.5 Hz, 1H), 1.36 (t, J = 6.6 Hz, 1H), 1.30 (d, J = 3.4 Hz, 1H), 1.14 (t, J = 5.5 Hz, 1H).

[0074] 13 C NMR (101 MHz, CDCl3) δ 152.30, 144.90, 142.33, 137.81, 132.39,129.36, 127.88 125.03, 121.08, 35.61, 31.25, 29.43, 24.61, 23.65. Example

[0075] This embodiment provides a method for preparing a nitrogen-containing heterocyclic carbene palladium complex C1, which specifically includes the following steps:

[0076] Compound E1 (0.2 mmol), palladium chloride (0.22 mmol), potassium carbonate (2 mmol), and 3-chloropyridine (1.2 mmol) were weighed into a reaction flask. Acetone was added to cover the solid, and the reaction was carried out at 60 °C for 8 h. After treatment, a yellow solid was obtained, namely the nitrogen-heterocyclic carbene palladium complex C1, with a yield of 45%.

[0077] 1H NMR (600 MHz, CDCl3) δ 8.67 (d, J = 2.3 Hz, 1H), 8.59 (dd, J = 5.6,1.3 Hz, 1H), 7.69 (s, 2H), 7.58 (t, J = 8.3, 1.8 Hz, 1H), 7.15 (s, 4H), 7.12– 7.09 (m, 1H), 6.98 (d, J = 1.3 Hz, 2H), 2.45 (d, J = 13.5 Hz, 17H), 1.31 (s, 16H).

[0078] 13 C NMR (101 MHz, CDCl3) δ 155.18, 151.42, 150.65, 149.73, 139.41,139.03, 137.63, 136.17, 133.81, 132.09, 129.54, 129.00, 126.38, 125.43,124.43, 122.99, 118.94, 35.53, 31.46, 21.53, 19.29. Example

[0079] This embodiment provides a method for preparing a nitrogen-containing heterocyclic carbene palladium complex C2, which specifically includes the following steps:

[0080] The only difference from Example 7 is that compound E1 is replaced with compound E2. The other steps are the same as in Example 7, yielding a yellow solid, namely the nitrogen-heterocyclic carbene palladium complex C2, with a yield of 56%.

[0081] 1 H NMR (400 MHz, CDCl3) δ 8.58 (d, J = 2.3 Hz, 1H), 8.49 (dd, J = 5.5,1.1 Hz, 1H), 7.68 (d, J = 0.9 Hz, 2H), 7.62 – 7.54 (m, 3H), 7.43 (d, J = 7.7Hz, 4H), 7.08 (dd, J = 8.2, 5.5 Hz, 1H), 6.98 (d, J = 1.0 Hz, 2H), 2.98 (t, J= 15.3, 7.7 Hz, 4H), 2.80 (t, J = 15.4, 7.5 Hz, 4H), 1.28 (s, 18H), 1.11 (t,J = 7.5 Hz, 12H).

[0082] 13 C NMR (101 MHz, CDCl3) δ 156.37, 151.35, 150.57, 149.66, 142.32,139.67, 137.59, 134.98, 132.07, 130.37, 129.02, 126.69, 126.44, 125.43,124.43, 122.93, 119.60, 35.53, 31.35, 25.11, 14.69. Example

[0083] This embodiment provides a method for preparing a nitrogen-containing heterocyclic carbene palladium complex C3, which specifically includes the following steps:

[0084] The only difference from Example 7 is that compound E1 is replaced with compound E3. The other steps are the same as in Example 7, yielding a yellow solid, namely the nitrogen-heterocyclic carbene palladium complex C3, with a yield of 57%.

[0085] 1 H NMR (400 MHz, CDCl3) δ 8.70 (d, J = 2.3 Hz, 1H), 8.62 (dd, J = 5.5,1.1 Hz, 1H), 7.64 (d, J = 12.3 Hz, 4H), 7.57 (d, J = 8.3 Hz, 1H), 7.49 (d, J= 7.8 Hz, 4H), 7.10 (dd, J = 8.2, 5.6 Hz, 1H), 6.81 (s, 2H), 3.39 (t, J =13.4, 6.7 Hz, 4H), 1.46 (d, J = 6.6 Hz, 12H), 1.24 (s, 18H), 0.91 (d, J = 6.8Hz, 12H).

[0086] 13 C NMR (101 MHz, CDCl3) δ 157.96, 150.81, 149.74, 147.42, 140.81,137.55, 133.99, 132.00, 130.82, 128.92, 126.41, 125.68, 124.79, 124.44,122.66, 120.90, 35.45, 31.18, 29.01, 25.83, 24.39. Example

[0087] This embodiment provides an arylated homopolymer A1 of a haloaromatic hydrocarbon, specifically including the following steps:

[0088] Under a nitrogen atmosphere, 0.5 mmol of 3,4-ethylenedioxythiophene, 0.5 mmol of 9,9-dioctylfluorene bromide, 0.5 mol% of the azahexacyclic carbene palladium complex C1, 30 mol% of 2,2-dimethylpropionic acid, and 1.5 mmol of K2CO3 were added to 4 mL of DMAc solvent and stirred at 100 °C for 24 h. After cooling to room temperature, the resulting mixture was poured into cold methanol, producing a large amount of yellow precipitate. The product was filtered, washed successively with distilled water and methanol, and then purified with n-hexane in a Soxhlet extractor to obtain a yellow solid, namely the arylized homopolymer A1 of haloaromatic hydrocarbons, with a yield of 92.5%. Example

[0089] This embodiment provides an arylated homopolymer A2 of a haloaromatic hydrocarbon, specifically including the following steps:

[0090] The only difference from Example 10 is that the nitrogen-heterocyclic carbene palladium complex C1 is replaced with nitrogen-heterocyclic carbene palladium complex C2. The other steps are the same as in Example 10, and a yellow solid, namely the arylated homopolymer A2 of the haloaromatic hydrocarbon, is obtained with a yield of 95.5%. Example

[0091] This embodiment provides an arylated homopolymer A3 of a haloaromatic hydrocarbon, specifically including the following steps:

[0092] The only difference from Example 10 is that the nitrogen-heterocyclic carbene palladium complex C1 is replaced with nitrogen-heterocyclic carbene palladium complex C3. The other steps are the same as in Example 10, and a yellow solid, namely the arylated homopolymer A3 of the haloaromatic hydrocarbon, is obtained with a yield of 98.9%.

[0093] The molecular weight and molecular weight distribution (PDI) of the arylized homopolymers A1-A3 of haloaromatic hydrocarbons prepared in Examples 10-12 are shown in Table 1.

[0094] Table 1. Molecular weight and molecular weight distribution of arylized homopolymers of halogenated aromatic hydrocarbons A1-A3.

[0095] Example homopolymer Number average molecular weight Mn Weight-average molecular weight Mw Molecular weight distribution PDI Example 10 A1 6538 10494 1.6 Example 11 A2 8062 12532 1.6 Example 12 A3 7623 11550 1.5

[0096] As shown in Table 1, the nitrogen-containing heterocyclic carbene palladium complex of the present invention can catalyze the arylation of haloaromatics to obtain homopolymers with narrow distribution and low molecular weight.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading this application specification, they can still modify or make equivalent substitutions to the specific implementation of the present invention, but these modifications or changes do not depart from the protection scope of the pending claims of the present invention.

Claims

1. A palladium complex of a nitrogen heterocyclic carbene, characterized in that, The structure of the azolide palladium complex is shown in formula (I): Formula (I); wherein R1, R2and R3are independently selected from methyl, and X is selected from Cl; or R1or R2are independently selected from isopropyl, R3is selected from H, and X is selected from Cl.

2. A process for the preparation of the azaheterocyclic carbene palladium complex according to claim 1, characterized in that, The method comprises the following steps: S1. reacting a substituted aniline with 4,7-di-tert-butylacenaphthenequinone in the presence of a catalyst and a solvent, purifying, to obtain a diimine compound; S2. reacting the diimine compound with chloromethyl ether to obtain compound E; S3. Compound E is reacted with palladium chloride, a substituted pyridine The reaction is carried out in the presence of an inorganic salt to give the palladium complex of the azacyclic carbene.

3. The process for the preparation of a palladium complex of a heterocyclic carbene according to claim 2, characterized in that, In S1, the catalyst is selected from anhydrous zinc chloride; The solvent is selected from glacial acetic acid; The temperature of the reaction is 110-130℃, and the time is 3-7h.

4. The process for the preparation of a palladium complex of a heterocyclic carbene according to claim 2, characterized in that, In S1, the molar ratio of the substituted aniline to 4,7-di-tert-butylbenzoquinone is 2-2.5:

1.

5. The process for the preparation of a carbene-palladium complex according to claim 2, characterized in that, In S1, the molar ratio of the catalyst to 4,7-di-tert-butylbenzoquinone is 2-2.5:

1.

6. The process for the preparation of a carbene-palladium complex according to claim 2, characterized in that, In S2, the molar ratio of the diimine compound to chloromethyl ether is 1:0.02-0.

05.

7. The process for the preparation of a carbene-palladium complex according to claim 2, characterized in that, In S2, the temperature of the reaction is 80-120℃, and the time is 18-30h; The reaction is carried out under an inert atmosphere.

8. The process for the preparation of a carbene-palladium complex according to claim 2, characterized in that, In S3, the molar ratio of the compound E to palladium chloride, substituted pyridine, and inorganic salt is 1:1-1.3:4-8:8-12.

9. The process for the preparation of a carbene-palladium complex according to claim 2, characterized in that, In S3, the inorganic salt is selected from potassium carbonate; The temperature of the reaction is 40-80℃, and the time is 6-10h.

10. The azolide palladium complex of any one of claims 1-3 or the azolide palladium complex prepared by the method of any one of claims 4-9 for use in catalyzing the arylative coupling reaction of halogenated aromatic hydrocarbons.

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