N-heterocyclic carbene palladium complex as well as preparation method and application thereof

Abstract

The invention discloses an N-heterocyclic carbene palladium complex as well as a preparation method and application thereof. The structure of the N-heterocyclic carbene palladium complex is as shown in a formula (I): # imgabs0 # formula (I), the N-heterocyclic carbene palladium complex can be used for catalyzing an arylation reaction of aryl halide and has the advantage of high yield, and an arylation homopolymer of aryl halide prepared through catalysis has the characteristics of narrow distribution and low molecular weight.

Description

Technical Field

[0001] The invention belongs to the technical field of carbene palladium complexes, and in particular relates to a nitrogen heterocyclic carbene palladium complex and a preparation method and application thereof. Background Art

[0002] The low molecular weight copolymer containing 3,4-ethylenedioxythiophene on the main chain not only has excellent electronic properties, but also has high solubility in polar and non-polar organic solvents. It can be used to prepare thin films for organic light-emitting devices to maximize the strength of the thin films and reduce the damage to the thin films by other substances. Therefore, the low molecular weight copolymer containing 3,4-ethylenedioxythiophene on the main chain has a wide range of applications in devices with electrical semiconductor characteristics.

[0003] In the prior art, tetrakistriphenylphosphine palladium is generally used as a catalyst to catalyze the preparation of a low molecular weight copolymer containing 3,4-ethylenedioxythiophene on the main chain, but it is difficult to catalyze the arylation of halogenated aromatics using tetrakistriphenylphosphine palladium as a catalyst. Then, the arylated homopolymer of halogenated aromatics is obtained. Therefore, the development of a catalyst for preparing a low molecular weight copolymer containing 3,4-ethylenedioxythiophene on the main chain with a narrow distribution of low molecular weight has the market value of isobutylene. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, a nitrogen heterocyclic carbene palladium complex is provided. The nitrogen heterocyclic carbene palladium complex of the present invention can be used to catalyze the arylation reaction of halogenated aromatic hydrocarbons and has the advantage of high yield. The arylated homopolymer of halogenated aromatic hydrocarbons prepared by catalysis has the characteristics of narrow distribution and low molecular weight.

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

[0006] Formula (I) Wherein, R1, R2 and R3 are independently selected from H or C1~C6 alkyl, and X is selected from Cl or Br.

[0007] In some embodiments of the present invention, R1, R2 and R3 are independently selected from H or C1~C3 alkyl.

[0008] 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.

[0009] Another object of the present invention is to provide a method for preparing the nitrogen heterocyclic carbene palladium complex, comprising the following steps: S1. will replace aniline reacting with 4,7-di-tert-butylacenaphthenequinone in the presence of a catalyst and a solvent, and 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 and substituted pyridine It reacts under the action of inorganic salts to obtain a nitrogen heterocyclic carbene palladium complex.

[0010] In some embodiments of the present invention, in S1, the catalyst is selected from anhydrous zinc chloride.

[0011] In some embodiments of the present invention, in S1, the solvent is selected from glacial acetic acid.

[0012] In some embodiments of the present invention, in S1, the reaction temperature is 110-130° C. and the reaction time is 3-7 h.

[0013] In some embodiments of the present invention, in S1, the molar ratio of the substituted aniline to 4,7-di-tert-butylacenaphthenequinone is 2-2.5:1.

[0014] In some embodiments of the present invention, in S1, the molar ratio of the catalyst to 4,7-di-tert-butylacenaphthenequinone is 2-2.5:1.

[0015] In some embodiments of the present invention, in S2, the molar ratio of the diimine compound to chloromethyl ether is 1:0.02-0.05.

[0016] In some embodiments of the present invention, in S2, the reaction temperature is 80-120° C. and the reaction time is 18-30 h.

[0017] In some embodiments of the present invention, in S2, the reaction is carried out under an inert atmosphere.

[0018] In some embodiments of the present invention, 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.

[0019] In some embodiments of the present invention, in S3, the inorganic salt is selected from potassium carbonate.

[0020] In some embodiments of the present invention, in S3, the reaction temperature is 40-80° C. and the reaction time is 6-10 h.

[0021] Another object of the present invention is to provide the use of the nitrogen heterocyclic carbene palladium complex or the nitrogen heterocyclic carbene palladium complex prepared by the preparation method of the nitrogen heterocyclic carbene palladium complex in catalyzing the arylation coupling reaction of halogenated aromatics.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) The nitrogen heterocyclic carbene palladium complex of the present invention is used to catalyze the arylation reaction of halogenated aromatic hydrocarbons and has the advantage of high yield. The arylated homopolymer of halogenated aromatic hydrocarbons prepared by the catalysis has the characteristics of narrow distribution and low molecular weight.

[0023] (2) The method for preparing the nitrogen heterocyclic carbene palladium complex of the present invention has the advantages of mild reaction conditions and high yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the H NMR spectrum of the diimine compound D1 prepared in Example 1.

[0025] Figure 2 This is the NMR carbon spectrum of the diimine compound D1 prepared in Example 1.

[0026] Figure 3 This is the H NMR spectrum of the diimine compound D2 prepared in Example 2.

[0027] Figure 4 This is the NMR carbon spectrum of the diimine compound D2 prepared in Example 2.

[0028] Figure 5 This is the H NMR spectrum of the diimine compound D3 prepared in Example 3.

[0029] Figure 6 This is the NMR carbon spectrum of the diimine compound D3 prepared in Example 3.

[0030] Figure 7 This is the H NMR spectrum of compound E1 obtained in Example 4.

[0031] Figure 8 This is the NMR carbon spectrum of compound E1 prepared in Example 4.

[0032] Fig. 9 This is the H NMR spectrum of compound E2 prepared in Example 5.

[0033] Fig.10 This is the NMR carbon spectrum of compound E2 prepared in Example 5.

[0034] Fig.11 This is the H NMR spectrum of compound E3 obtained in Example 6.

[0035] Fig.12 This is the NMR carbon spectrum of compound E3 prepared in Example 6.

[0036] Fig.13 This is the H NMR spectrum of the nitrogen heterocyclic carbene palladium complex C1 prepared in Example 7.

[0037] Fig.14This is the NMR carbon spectrum of the nitrogen heterocyclic carbene palladium complex C1 prepared in Example 7.

[0038] Fig.15 This is the H NMR spectrum of the nitrogen heterocyclic carbene palladium complex C2 prepared in Example 8.

[0039] Fig.16 This is the NMR carbon spectrum of the nitrogen heterocyclic carbene palladium complex C2 prepared in Example 8.

[0040] Fig.17 This is the H NMR spectrum of the nitrogen heterocyclic carbene palladium complex C3 prepared in Example 9.

[0041] Fig.18 This is the NMR carbon spectrum of the nitrogen heterocyclic carbene palladium complex C3 prepared in Example 9. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0043] All raw materials of the present invention are conventionally commercially available.

[0044] The nitrogen heterocyclic carbene palladium complexes of each embodiment are prepared by the following reaction route: Example

[0045] This embodiment provides a preparation method of a diimine compound D1, which specifically includes the following steps: S1. 2,4,6-trimethylaniline (4.4mmol), 4,7-di-tert-butylacenaphthenequinone (2mmol), and anhydrous zinc chloride (4.6mmol) were added to a 100 ml side-mouth bottle in sequence, and 50 ml of glacial acetic acid was added as solvent. The reaction was refluxed at 120°C under N2 protection for 5 hours. After the reaction was completed, the solution was cooled to room temperature. An orange-yellow solid was generated in the solution. The solution was filtered and the filter cake was rinsed with glacial acetic acid for several times to remove the unreacted raw materials. The solid obtained by filtration was dried and dissolved in dichloromethane. The solution was dezincified with 100 mL of potassium oxalate aqueous solution (4.6 g / L). After stirring for 5 hours, the white zinc salt was removed by filtration. The remaining organic layer was extracted with water for several times, and then spin-dried and recrystallized with (dichloromethane / n-hexane) to obtain orange-yellow crystals, i.e., diimine compound D1, with a yield of 64%; 1H 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). 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

[0046] This embodiment provides a preparation of a diimine compound D2, which specifically includes the following steps: The only difference from Example 1 is that 2,4,6-trimethylaniline is replaced by 2,6-diethylaniline. The other steps are the same as Example 1, and an orange solid, namely, diimine compound D2, is obtained with a yield of 62%; 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). 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

[0047] This embodiment provides a preparation of a diimine compound D3, which specifically includes the following steps: The only difference from Example 1 is that 2,4,6-trimethylaniline is replaced by 2,6-diisopropylaniline. The other steps are the same as Example 1, and an orange solid, namely, diimine compound D3, is obtained with a yield of 68%; 1H 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). 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

[0048] This embodiment provides a preparation of compound E1, which specifically includes the following steps: Weigh the diimine compound D1 (1.0 mmol) into a 25 ml stoppered bottle, add 3-4 ml of chloromethyl ether to dissolve it, expel the air in the bottle with N2 and seal it, react at 100°C for 24 hours, and after treatment, obtain compound E1 with a yield of 78%; 1 H 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). 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

[0049] This embodiment provides a preparation of compound E2, which specifically includes the following steps: The only difference from Example 4 is that the diimine compound D1 is replaced by the diimine compound D2. The other steps are the same as Example 4 to obtain compound E2 with a yield of 52%; 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). 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

[0050] This embodiment provides a preparation of compound E3, which specifically includes the following steps: The only difference from Example 4 is that the diimine compound D1 is replaced by the diimine compound D3. The other steps are the same as Example 4 to obtain compound E3 with a yield of 48%; 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). 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

[0051] This embodiment provides a preparation of a nitrogen heterocyclic carbene palladium complex C1, which specifically includes the following steps: Weigh compound E1 (0.2 mmol), palladium chloride (0.22 mmol), potassium carbonate (2 mmol), and 3-chloropyridine (1.2 mmol) into a reaction bottle, add acetone to cover the solid, react at 60°C for 8 h, and after treatment, obtain a yellow solid, i.e., nitrogen heterocyclic carbene palladium complex C1, with a yield of 45%; 1 H 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). 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

[0052] This embodiment provides a preparation of a nitrogen heterocyclic carbene palladium complex C2, which specifically includes the following steps: The only difference from Example 7 is that Compound E1 is replaced by Compound E2. The other steps are the same as Example 7, and a yellow solid, namely, nitrogen heterocyclic carbene palladium complex C2, is obtained with a yield of 56%; 1H 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). 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

[0053] This embodiment provides a preparation of a nitrogen heterocyclic carbene palladium complex C3, which specifically includes the following steps: The only difference from Example 7 is that Compound E1 is replaced by Compound E3. The other steps are the same as Example 7, and a yellow solid, namely, nitrogen heterocyclic carbene palladium complex C3, is obtained with a yield of 57%; 1H 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). 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

[0054] This embodiment provides an aryl homopolymer A1 of a halogenated aromatic hydrocarbon, which specifically comprises the following steps:

[0055] Under nitrogen atmosphere, 3,4-ethylenedioxythiophene (0.5 mmol), 9,9-dioctylbromofluorene (0.5 mmol), nitrogen heterocyclic carbene palladium complex C1 (0.5 mol %), 2,2-dimethylpropionic acid (30 mol %) and K2CO3 (1.5 mmol) were added to 4 mL DMAc solvent and stirred at 100°C for 24 h. After cooling to room temperature, the resulting mixture was poured into cold methanol to produce a large amount of yellow precipitate, which was obtained by filtration, washed with distilled water and methanol in turn, and then purified with n-hexane in a Soxhlet extractor to obtain a yellow solid, i.e., arylated homopolymer A1 of halogenated aromatics, with a yield of 92.5%. Example

[0056] This embodiment provides an aryl homopolymer A2 of a halogenated aromatic hydrocarbon, which specifically comprises the following steps: The only difference from Example 10 is that the nitrogen heterocyclic carbene palladium complex C1 is replaced by the nitrogen heterocyclic carbene palladium complex C2. The other steps are the same as Example 10, and a yellow solid, i.e., the arylated homopolymer A2 of halogenated aromatic hydrocarbon, is obtained with a yield of 95.5%. Example

[0057] This embodiment provides an aryl homopolymer A3 of a halogenated aromatic hydrocarbon, which specifically comprises the following steps: The only difference from Example 10 is that the nitrogen heterocyclic carbene palladium complex C1 is replaced by the nitrogen heterocyclic carbene palladium complex C3, and the other steps are the same as Example 10, to obtain a yellow solid, i.e., the arylated homopolymer A3 of halogenated aromatic hydrocarbon, with a yield of 98.9%.

[0058] The molecular weights and molecular weight distributions PDI of the arylated homopolymers A1-A3 of halogenated aromatic hydrocarbons obtained in Examples 10-12 are shown in Table 1.

[0059] Table 1. Molecular weight and molecular weight distribution of aryl halides homopolymers A1~A3.

[0060] Example Homopolymer Number average molecular weight Mn Weight average molecular weight Mw Molecular weight distribution PDI Example 10 A1 6538 10494 1.6 Embodiment 11 A2 8062 12532 1.6 Example 12 A3 7623 11550 1.5 As can be seen from Table 1, the nitrogen heterocyclic carbene palladium complex of the present invention can catalyze the arylation of halogenated aromatic hydrocarbons to obtain a homopolymer with a narrow distribution and low molecular weight.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that after reading the specification of this application, the technicians can still modify or replace the specific implementation mode of the present invention with equivalents, but these modifications or changes do not deviate from the scope of protection of the pending claims of the present application.

Claims

1. A nitrogen heterocyclic carbene palladium complex, characterized in that: The structure of the nitrogen heterocyclic carbene palladium complex is shown in formula (I): Formula (I) Wherein, R1, R2 and R3 are independently selected from H or C1~C6 alkyl, and X is selected from Cl or Br.

2. The nitrogen heterocyclic carbene palladium complex according to claim 1, characterized in that The R1, R2 and R3 are independently selected from H or C1~C3 alkyl.

3. The nitrogen heterocyclic carbene palladium complex according to claim 1, characterized in that The 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.

4. A method for preparing the nitrogen heterocyclic carbene palladium complex according to any one of claims 1 to 3, characterized in that: The steps include: S1. will replace aniline reacting with 4,7-di-tert-butylacenaphthenequinone in the presence of a catalyst and a solvent, and 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 and substituted pyridine It reacts under the action of inorganic salts to obtain a nitrogen heterocyclic carbene palladium complex.

5. The method for preparing the nitrogen heterocyclic carbene palladium complex according to claim 4, characterized in that: In S1, the catalyst is selected from anhydrous zinc chloride; The solvent is selected from glacial acetic acid; The reaction temperature is 110-130° C. and the reaction time is 3-7 hours.

6. The method for preparing the nitrogen heterocyclic carbene palladium complex according to claim 4, characterized in that: In S1, the molar ratio of the substituted aniline to 4,7-di-tert-butylacenaphthenequinone is 2-2.5:1; The molar ratio of the catalyst to 4,7-di-tert-butylacenaphthenequinone is 2-2.5:

1.

7. The method for preparing the nitrogen heterocyclic carbene palladium complex according to claim 4, characterized in that: In S2, the molar ratio of the diimine compound to chloromethyl ether is 1:0.02-0.

05.

8. The method for preparing the nitrogen heterocyclic carbene palladium complex according to claim 4, characterized in that: In S2, the reaction temperature is 80-120°C and the reaction time is 18-30h; The reaction was carried out under an inert atmosphere.

9. The method for preparing the nitrogen heterocyclic carbene palladium complex according to claim 4, 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; The inorganic salt is selected from potassium carbonate; The reaction temperature is 40-80°C and the reaction time is 6-10 hours.

10. Use of the nitrogen heterocyclic carbene palladium complex as claimed in any one of claims 1 to 3 or the nitrogen heterocyclic carbene palladium complex as claimed in any one of claims 4 to 9 in catalyzing the arylation coupling reaction of halogenated aromatics.

Images