Diimine palladium complex as well as preparation method and application thereof

Abstract

The invention discloses a diimine palladium complex and a preparation method and application thereof, the structural formula of the diimine palladium complex is as shown in formula (I): # imgabs0 # formula (I), R1 and R2 are independently selected from hydrogen or tertiary butyl, and R1 and R2 are not hydrogen at the same time; the diimine palladium complex provided by the invention can be subjected to catalytic polymerization at high temperature to prepare a high-molecular-weight and high-regularity long ether chain thiophene copolymer, and has wide application prospects in the fields of solar cells, organic transistors, electrochromic devices, chemical sensors, electromagnetic shielding materials and the like.

Description

Technical Field

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

[0002] Poly (3-hexylthiophene) is a derivative of polythiophene, which has good stability and solution coating performance, and has unique photoelectric properties and high hole transport performance. Therefore, poly (3-hexylthiophene) (P3HT) has become one of the most commonly used polymer hole transport materials. However, the efficiency of perovskite solar devices prepared using P3HT alone as a hole transport layer is not ideal. The main reason is that there is a physical poor contact between P3HT and the perovskite interface, which will cause serious recombination of carriers, resulting in significant voltage and current losses, thereby affecting the energy conversion efficiency of perovskite solar cells. Therefore, it is an urgent problem to modify P3HT, improve the contact between the polymer and the perovskite interface, and then improve the energy conversion efficiency of perovskite solar cells.

[0003] The inventors found in the experiment that copolymerizing long ether chain thiophene with P3HT can improve the problem of poor physical contact between P3HT and the perovskite interface. However, there are few existing technologies that record the preparation of catalysts for copolymerizing long ether chain thiophene with P3HT. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects and shortcomings of the prior art and provide a diimine palladium complex, which can be catalytically polymerized at high temperature to prepare a long ether chain thiophene copolymer with high molecular weight and high regularity.

[0005] The object of the present invention is to provide a diimine palladium complex, the structural formula of the diimine palladium complex is shown in formula (I):

[0006] Formula (I) Wherein, R1 and R2 are independently selected from hydrogen or tert-butyl, and R1 and R2 are not hydrogen at the same time.

[0007] In some embodiments of the present invention, the structural formula of the diimine palladium complex is as shown in formula (I):

[0008] Formula (I) Wherein, R1 is selected from hydrogen, and R2 is selected from tert-butyl.

[0009] In some embodiments of the present invention, the structural formula of the diimine palladium complex is as shown in formula (I):

[0010] Formula (I) Wherein, R1 is selected from tert-butyl, and R2 is selected from hydrogen.

[0011] Another object of the present invention is to provide a method for preparing the diimine palladium complex, comprising the following steps: Ligand Reaction with (COD)PdCl2 to obtain the diimine palladium complex.

[0012] In some embodiments of the present invention, the molar ratio of the ligand to (COD)PdCl2 is 1:1.05~1.2.

[0013] In some embodiments of the present invention, the reaction temperature is 50-70° C. and the reaction time is 12-20 h.

[0014] In some embodiments of the present invention, the method for preparing the ligand comprises the following steps: Substituted aniline Acenaphthenequinone Reaction to obtain the ligand.

[0015] In some embodiments of the present invention, the molar ratio of the substituted aniline to acenaphthenequinone is 2.05-2.20:1.

[0016] In some embodiments of the present invention, the reaction temperature is 130-150° C. and the reaction time is 4-7 h.

[0017] Another object of the present invention is to provide the use of the diimine palladium complex or the diimine palladium complex prepared by the preparation method of the diimine palladium complex in the preparation of long ether chain thiophene copolymers.

[0018] In some embodiments of the present invention, the structure of the long ether chain thiophene copolymer is shown in formula (I):

[0019] Formula (I) Wherein, the number average molecular weight of the long ether chain thiophene copolymer is 6.5~8.9KDa.

[0020] In some embodiments of the present invention, the molar percentage of the 3-(2-butoxyethyl)thiophene chain segment in the long ether chain thiophene copolymer chain segment is 4.7% to 20%.

[0021] In some embodiments of the present invention, the molar percentage of the 3-(2-butoxyethyl)thiophene chain segment in the long ether chain thiophene copolymer chain segment is 4.7% to 8.3%.

[0022] In some embodiments of the present invention, the molar percentage of the 3-(2-butoxyethyl)thiophene chain segment in the long ether chain thiophene copolymer chain segment is 16% to 20%.

[0023] In some embodiments of the present invention, the long ether chain thiophene copolymer is a random copolymer.

[0024] In some embodiments of the present invention, the HT value of the long ether chain thiophene copolymer is ≥90%, and the PDI is ≥2.5.

[0025] Another object of the present invention is to provide a method for preparing a long ether chain thiophene copolymer, comprising the following steps: Under the catalysis of the diimine palladium complex shown in formula (I), 2-bromo-3-(2-butoxyethyl)thiophene and 2-bromo-3-hexylthiophene react to obtain the long ether chain thiophene copolymer; The structural formula of the diimine palladium complex represented by formula (I) is as follows:

[0026] Formula (I) Wherein, R1 and R2 are independently selected from hydrogen or tert-butyl, and R1 and R2 are not hydrogen at the same time.

[0027] In some embodiments of the present invention, the molar ratio of 2-bromo-3-(2-butoxyethyl)thiophene to 2-bromo-3-hexylthiophene is 1-5:15-19.

[0028] In some embodiments of the present invention, the ratio of the total mole of 2-bromo-3-(2-butoxyethyl)thiophene and 2-bromo-3-hexylthiophene to the mole of the palladium catalyst is 1:0.001-0.01.

[0029] In some embodiments of the present invention, the reaction temperature is 80-120° C. and the reaction time is 12-36 hours.

[0030] In some embodiments of the present invention, the reaction further contains an inorganic base, an organic acid and a solvent.

[0031] In some embodiments of the present invention, the inorganic base includes at least one of potassium carbonate and sodium carbonate.

[0032] In some embodiments of the present invention, the organic acid includes at least one of pivalic acid and caproic acid.

[0033] In some embodiments of the present invention, the solvent includes N,N-dimethylacetamide.

[0034] In some embodiments of the present invention, the ratio of the total mole of 2-bromo-3-(2-butoxyethyl)thiophene and 2-bromo-3-hexylthiophene to the mole of the inorganic base is 1-1.5:1-1.5.

[0035] In some embodiments of the present invention, the ratio of the total mole of 2-bromo-3-(2-butoxyethyl)thiophene and 2-bromo-3-hexylthiophene to the mole of the organic acid is 2.5-4.5:1.

[0036] In some embodiments of the present invention, after the reaction is completed, a purification step is further included.

[0037] Compared with the prior art, the present invention has the following beneficial effects: The diimine palladium complex provided by the present invention can be used to prepare long ether chain thiophene copolymers at high temperature. The prepared long ether chain thiophene copolymers have the advantages of high molecular weight and high regularity, and have obvious economic benefits. They have broad application prospects in the fields of solar cells, organic transistors, electrochromic devices, chemical sensors, electromagnetic shielding materials, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is the H NMR spectrum of the diimine palladium complex C1 provided in Example 3.

[0039] Figure 2 This is the NMR carbon spectrum of the diimine palladium complex C1 provided in Example 3.

[0040] Figure 3 This is the H NMR spectrum of the diimine palladium complex C2 provided in Example 4.

[0041] Figure 4 This is the NMR carbon spectrum of the diimine palladium complex C2 provided in Example 4. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the concept of the present invention and the technical effects produced in combination with the embodiments, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by technicians in this field without creative work are all within the scope of protection of the present invention. The test methods used in the embodiments are all conventional methods unless otherwise specified; the materials, reagents, etc. used, unless otherwise specified, can all be reagents and materials obtained from commercial channels.

[0043] The diimine palladium complex was prepared by the following reaction route:

[0044] In the following examples, the content of 3-(2-butoxyethyl)thiophene segments in the long ether chain thiophene copolymer was determined by nuclear magnetic resonance, the long ether chain thiophene copolymer was dissolved in deuterated chloroform, TMS was used as an internal standard, and the measurement temperature was 25°C. The molecular weight or degree of polymerization of the long ether chain thiophene copolymer was determined by gel permeation chromatography (GPC) with THF mobile phase. Among them, HT and HT values ​​represent isotacticity, and PDI represents molecular weight distribution index; The structural formula of 2-bromo-3-(2-butoxyethyl)thiophene is shown below: .

[0045] Example 1

[0046] This embodiment provides a ligand L1, and its synthesis method is as follows: Under nitrogen atmosphere, p-tert-butylaniline (2.2mmol), acenaphthenequinone (1mmol), and anhydrous ZnCl2 (0.3g) were added to a branched bottle in sequence, and 5mL of glacial acetic acid was added as a solvent. The temperature was slowly raised to 140°C, and condensed and refluxed for 5h. The reaction was cooled to room temperature, filtered (the solid was rinsed with n-hexane), and the obtained zinc complex was dissolved in a beaker with dichloromethane after drying. Potassium oxalate aqueous solution was added to the beaker and stirred for 12h to dezincify it. The organic layer was taken after standing and separation, anhydrous sodium sulfate was added to remove water, filtered, spin-dried, and recrystallized with anhydrous ethanol to obtain a yellow solid ligand L1 with a yield of 68%.

[0047] Example 2

[0048] This embodiment provides a ligand L2, and its synthesis method is as follows: Under nitrogen atmosphere, m-tert-butylaniline (2.2 mmol), acenaphthenequinone (1 mmol), and anhydrous ZnCl2 (0.3 g) were added to a branched bottle in sequence, and 5 mL of glacial acetic acid was added as a solvent. The temperature was slowly raised to 140°C, and condensed and refluxed for 5 hours. The reaction was cooled to room temperature, filtered (the solid was rinsed with n-hexane), and the obtained zinc complex was dissolved in a beaker with dichloromethane after drying. Potassium oxalate aqueous solution was added to the beaker and stirred for 12 hours to dezincify it. The organic layer was taken after standing and separation, anhydrous sodium sulfate was added to remove water, filtered, spin-dried, and recrystallized with anhydrous ethanol to obtain a yellow solid ligand L2 with a yield of 71%.

[0049] Example 3

[0050] This embodiment provides a diimine palladium complex C1, and its synthesis method is as follows: Under nitrogen atmosphere, ligand L1 (0.5 mmol), (COD)PdCl2 (0.55 mmol) and methanol (8 ml) were added to a branched bottle, condensed and refluxed at 60°C for 16 h. After the reaction was completed, it was cooled to room temperature and passed through a column by dry method using dichloromethane as eluent. The filtrate was collected and spin-dried, a small amount of dichloromethane was added to dissolve it, and the mixture was slowly added dropwise to a stirred anhydrous ethanol solution to precipitate a solid. The solid was washed several times, filtered and dried to obtain a solid compound C1 with a yield of 85%.

[0051] Example 4

[0052] This embodiment provides a diimine palladium complex C2, and its synthesis method is as follows: Under nitrogen atmosphere, ligand L2 (0.5mmol), (COD)PdCl2 (0.55mmol) and methanol (8ml) were added to a branched bottle and refluxed at 60°C for 16h. After the reaction was completed, it was cooled to room temperature and passed through a column by dry method using dichloromethane as eluent. The filtrate was collected and spin-dried, a small amount of dichloromethane was added to dissolve it, and the mixture was slowly added dropwise to a stirred anhydrous ethanol solution to precipitate a solid. The solid was washed several times, filtered and dried to obtain a yellow solid compound C2 with a yield of 82%.

[0053] Example 5

[0054] This embodiment provides a long ether chain thiophene copolymer L1, and the synthesis method thereof is as follows: Under nitrogen atmosphere, 2-bromo-3-(2-butoxyethyl)thiophene (0.025mmol), 2-bromo-3-hexylthiophene (0.475mmol), potassium carbonate (0.75mmol), diimine palladium catalyst C1 (0.25mmol%), pivalic acid (0.15mmol), and dimethylacetamide (4mL) were reacted at 100°C for 24h, and precipitated in methanol to obtain a long ether chain thiophene copolymer L1 with a yield of 66%, an HT value of 91%, a PDI of 2.61, a number average molecular weight Mn of 8.9KDa, and a molar percentage of 3-(2-butoxyethyl)thiophene segments in the long ether chain thiophene copolymer segments of 4.7%, that is, a copolymerization degree of 4.7mmol; the structures of the diimine palladium catalyst C1 and the random long ether chain thiophene copolymer L1 are shown below:

[0055] Among them, x=4.7mmol%, y=95.3mmol%.

[0056] Example 6

[0057] This embodiment provides a long ether chain thiophene copolymer L2, and its synthesis method is as follows: Under nitrogen atmosphere, 2-bromo-3-(2-butoxyethyl)thiophene (0.05mmol), 2-bromo-3-hexylthiophene (0.45mmol), potassium carbonate (0.75mmol), diimine palladium catalyst C2 (0.25mmol%), pivalic acid (0.15mmol), dimethylacetamide (4mL) were reacted at 100°C for 24h, and precipitated in methanol to obtain a long ether chain thiophene copolymer L2 with a yield of 50%, a HT value of 92%, a PDI of 2.72, a number average molecular weight Mn of 8.3KDa, and a molar percentage of 3-(2-butoxyethyl)thiophene segments in the long ether chain thiophene copolymer segments of 5.6%, that is, a copolymerization degree of 5.6mmol; the structures of the diimine palladium catalyst C2 and the random long ether chain thiophene copolymer L2 are shown below:

[0058] Among them, x=5.6mmol%, y=94.4mmol%.

[0059] It can be seen from Examples 5 and 6 that the long ether chain thiophene copolymer of the present invention has a random structure and has the characteristics of high regularity and high molecular weight.

[0060] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A diimine palladium complex, characterized in that The structural formula of the diimine palladium complex is shown in formula (I): Formula (I) Wherein, R1 and R2 are independently selected from hydrogen or tert-butyl, and R1 and R2 are not hydrogen at the same time.

2. The diimine palladium complex according to claim 1, characterized in that The structural formula of the diimine palladium complex is shown in formula (I): Formula (I) Wherein, R1 is selected from hydrogen, and R2 is selected from tert-butyl.

3. The diimine palladium complex according to claim 2, characterized in that The structural formula of the diimine palladium complex is shown in formula (I): Formula (I) Wherein, R1 is selected from tert-butyl, and R2 is selected from hydrogen.

4. The method for preparing the diimine palladium complex according to any one of claims 1 to 3, characterized in that: The steps include: Ligand Reaction with (COD)PdCl2 to obtain the diimine palladium complex.

5. The method for preparing a diimine palladium complex according to claim 4, wherein The molar ratio of the ligand to (COD)PdCl2 is 1:1.05-1.

2.

6. The method for preparing a diimine palladium complex according to claim 4, wherein: The reaction temperature is 50-70°C and the reaction time is 12-20 hours.

7. The method for preparing a diimine palladium complex according to claim 4, wherein: The preparation method of the ligand comprises the following steps: Substituted aniline Acenaphthenequinone Reaction to obtain the ligand.

8. The method for preparing a diimine palladium complex according to claim 7, wherein: The molar ratio of the substituted aniline to acenaphthenequinone is 2.05-2.20:

1.

9. The method for preparing a diimine palladium complex according to claim 7, wherein: The reaction temperature is 130-150° C. and the reaction time is 4-7 hours.

10. Use of the diimine palladium complex according to any one of claims 1 to 3 or the diimine palladium complex prepared by the method for preparing the diimine palladium complex according to any one of claims 4 to 9 in the preparation of long ether chain thiophene copolymers.

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