A diimine palladium complex, its preparation method and use

Abstract

The application discloses a diimine palladium complex and a preparation method and application thereof, and a structure formula of the diimine palladium complex is shown as formula (I): wherein R1 and R2 are independently selected from hydrogen or a tert-butyl group, and R1 and R2 are not hydrogen at the same time. The diimine palladium complex provided by the application can be used for catalyzing polymerization at high temperature to obtain a long ether chain thiophene copolymer with high molecular weight and high regularity, and has a wide application prospect in the fields of solar cells, organic transistors, electrochromic devices, chemical sensors, electromagnetic shielding materials and the like.

Description

TECHNICAL FIELD

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

[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, so poly-3-hexylthiophene (P3HT) becomes one of the most commonly used polymer hole transport materials. However, the efficiency of the perovskite solar device prepared by using P3HT alone as a hole transport layer is not ideal, and the main reason is that there is physical poor contact between P3HT and the perovskite interface, which will cause serious recombination of carriers, resulting in obvious voltage and current loss, and thus affecting the energy conversion efficiency of the perovskite solar cell. Therefore, it is an urgent problem to be solved to modify P3HT, improve the contact between the polymer and the perovskite interface, and thus improve the energy conversion efficiency of the perovskite solar cell.

[0003] The inventors found in the experimental process that copolymerization of long ether chain thiophene and P3HT can improve the problem of physical poor contact between P3HT and the perovskite interface. However, so far, there is little prior art to record the catalyst for preparing long ether chain thiophene and P3HT copolymer. SUMMARY

[0004] The purpose of the present application is to overcome the defects and deficiencies of the prior art, and to provide a diimine palladium complex, which can catalyze the polymerization at high temperature to obtain a long ether chain thiophene copolymer with high molecular weight and high regularity.

[0005] The purpose of the present application is to provide a diimine palladium complex, and the structural formula of the diimine palladium complex is shown as formula (I):

[0006]

[0007] Formula (I)

[0008] wherein R1 and R2 are independently selected from hydrogen or tert-butyl, and R1 and R2 are not hydrogen at the same time.

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

[0010]

[0011] Formula (I)

[0012] wherein R1 is selected from hydrogen, and R2 is selected from tert-butyl.

[0013] In some embodiments of the present application, the structure of the palladium diimine complex is shown in formula (I):

[0014]

[0015] Formula (I)

[0016] wherein R1 is selected from tert-butyl, and R2 is selected from hydrogen.

[0017] Another object of the present application is to provide a preparation method of the palladium diimine complex, comprising the following steps:

[0018] Ligand reacting with (COD)PdCl2 to obtain the palladium diimine complex.

[0019] In some embodiments of the present application, the molar ratio of the ligand to (COD)PdCl2 is 1:1.05-1.2.

[0020] In some embodiments of the present application, the reaction temperature is 50-70℃, and the reaction time is 12-20h.

[0021] In some embodiments of the present application, the preparation method of the ligand comprises the following steps:

[0022] Substituted aniline reacting with acenaphthenequinone to obtain the ligand.

[0023] In some embodiments of the present application, the molar ratio of the substituted aniline to acenaphthenequinone is 2.05-2.20:1.

[0024] In some embodiments of the present application, the reaction temperature is 130-150℃, and the reaction time is 4-7h.

[0025] Still another object of the present application is to provide the use of the palladium diimine complex or the palladium diimine complex prepared by the preparation method of the palladium diimine complex in the preparation of long ether chain thiophene copolymer.

[0026] In some embodiments of the present application, the structure of the long ether chain thiophene copolymer is shown in formula (I):

[0027]

[0028] Formula (I)

[0029] wherein the number average molecular weight of the long ether chain thiophene copolymer is 6.5-8.9KDa.

[0030] In some embodiments of the present application, the 3-(2-butoxyethyl)thiophene segment accounts for 4.7% to 20% of the molar percentage of the long ether chain thiophene copolymer segment.

[0031] In some embodiments of the present application, the 3-(2-butoxyethyl)thiophene segment accounts for 4.7% to 8.3% of the molar percentage of the long ether chain thiophene copolymer segment.

[0032] In some embodiments of the present application, the 3-(2-butoxyethyl)thiophene segment accounts for 16% to 20% of the molar percentage of the long ether chain thiophene copolymer segment.

[0033] In some embodiments of the present application, the long ether chain thiophene copolymer is a random copolymer.

[0034] In some embodiments of the present application, the long ether chain thiophene copolymer has a HT value of ≥ 90% and a PDI of ≥ 2.5.

[0035] Another object of the present application is to provide a preparation method of the long ether chain thiophene copolymer, comprising the following steps:

[0036] under the catalysis of the diimine palladium complex shown in formula (I), 2-bromo-3-(2-butoxyethyl)thiophene and 2-bromo-3-hexylthiophene are reacted to obtain the long ether chain thiophene copolymer;

[0037] The structural formula of the diimine palladium complex shown in formula (I) is as follows:

[0038]

[0039] Formula (I)

[0040] wherein, R1, R2 are independently selected from hydrogen or tert-butyl, and R1, R2 are not hydrogen at the same time.

[0041] In some embodiments of the present application, the molar ratio of the 2-bromo-3-(2-butoxyethyl)thiophene to the 2-bromo-3-hexylthiophene is 1 to 5: 15 to 19.

[0042] In some embodiments of the present application, the ratio of the total moles of the 2-bromo-3-(2-butoxyethyl)thiophene and the 2-bromo-3-hexylthiophene to the moles of the palladium catalyst is 1: 0.001 to 0.01.

[0043] In some embodiments of the present application, the reaction temperature is 80 to 120°C, and the reaction time is 12 to 36 hours.

[0044] In some embodiments of the present application, the reaction further contains inorganic base, organic acid and solvent.

[0045] In some embodiments of the present invention, the inorganic base includes at least one of potassium carbonate and sodium carbonate.

[0046] In some embodiments of the present invention, the organic acid includes at least one of pivalic acid and hexanoic acid.

[0047] In some embodiments of the present invention, the solvent includes N,N-dimethylacetamide.

[0048] 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.

[0049] 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.

[0050] In some embodiments of the present invention, after the reaction is completed, a purification step is further included.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The diimine palladium complex provided by the present invention can be used to prepare long ether-chain thiophene copolymers at high temperatures. The prepared long ether-chain thiophene copolymers have the advantages of high molecular weight and high regularity, have obvious economic benefits, and 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

[0053] Figure 1 This is the H NMR spectrum of the diimine palladium complex C1 provided in Example 3.

[0054] Figure 2 This is the NMR carbon spectrum of the diimine palladium complex C1 provided in Example 3.

[0055] Figure 3 This is the H NMR spectrum of the diimine palladium complex C2 provided in Example 4.

[0056] Figure 4 This is the NMR carbon spectrum of the diimine palladium complex C2 provided in Example 4. DETAILED DESCRIPTION

[0057] The concept and the technical effects of the present application will be described clearly and completely in combination with the embodiments, so that the purpose, features and effects of the present application can be fully understood. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application. The test methods used in the embodiments are conventional methods unless otherwise specified. The materials and reagents used in the embodiments are commercially available unless otherwise specified.

[0058] The diimine palladium complex is prepared by the following reaction route:

[0059]

[0060] In the following embodiments, the content of 3-(2-butoxyethyl)thiophene segment in the long ether chain thiophene copolymer is determined by nuclear magnetic resonance instrument. The long ether chain thiophene copolymer is dissolved in deuterated chloroform, and TMS is used as an internal standard. The determination temperature is 25°C. The molecular weight or polymerization degree of the long ether chain thiophene copolymer is determined by THF mobile phase gel permeation chromatography (GPC). Among them, HT and HT values represent isotacticity, and PDI represents molecular weight distribution index.

[0061] The structural formula of 2-bromo-3-(2-butoxyethyl)thiophene is as follows:

[0062] .

[0063] Example 1

[0064] The present embodiment provides a ligand L1, and the synthesis method thereof is as follows:

[0065] Under a nitrogen atmosphere, p-tert-butylaniline (2.2 mmol), acenaphthenequinone (1 mmol), and anhydrous ZnCl2 (0.3 g) were sequentially added to a flask, 5 mL of ice acetic acid was added as a solvent, and the temperature was slowly increased to 140°C. Condensation reflux was performed for 5 h. The reaction was cooled to room temperature, and filtration was performed (the solid was washed with n-hexane). After drying, the obtained zinc complex was dissolved in dichloromethane in a beaker. Potassium oxalate aqueous solution was added to the beaker and stirred for 12 h to remove zinc. The organic layer was separated by standing, and anhydrous sodium sulfate was added to remove water. Filtration was performed, and the filtrate was dried by rotary evaporation. Recrystallization was performed with anhydrous ethanol to obtain yellow solid ligand L1, and the yield was 68%.

[0066] Example 2

[0067] The present embodiment provides a ligand L2, and the synthesis method thereof is as follows:

[0068] Under nitrogen atmosphere, m-tert-butylaniline (2.2 mmol), acenaphthenequinone (1 mmol), anhydrous ZnCl2(0.3 g) were added into a flask in turn, 5 mL of glacial acetic acid was added as solvent, slowly heated to 140 °C, and condensed backflow for 5 h. The reaction was cooled to room temperature, and filtered (with n-hexane to wash the solid). The obtained zinc complex was dissolved in a beaker with dichloromethane, and an aqueous solution of potassium oxalate was added to the beaker and stirred for 12 h to remove zinc. The organic layer was separated by standing, and anhydrous potassium sulfate was added to remove water. After filtration and rotary evaporation, the yellow solid ligand L2 was obtained by recrystallization with anhydrous ethanol, with a yield of 71%.

[0069] Example 3

[0070] This example provides a diimine palladium complex C1, and the synthesis method is as follows:

[0071] Under nitrogen atmosphere, ligand L1 (0.5 mmol), (COD)PdCl2 (0.55 mmol), and methanol (8 mL) were added into a flask, and condensed backflow at 60 °C for 16 h. After the reaction was completed, the reaction was cooled to room temperature, and dry column chromatography was performed with dichloromethane as the eluent. The filtrate was collected and rotary evaporated. A small amount of dichloromethane was added to dissolve the solid, which was slowly added to an anhydrous ethanol solution under stirring. The solid was precipitated and washed several times. After filtration and drying, the solid compound C1 was obtained, with a yield of 85%.

[0072] Example 4

[0073] This example provides a diimine palladium complex C2, and the synthesis method is as follows:

[0074] Under nitrogen atmosphere, ligand L2 (0.5 mmol), (COD)PdCl2 (0.55 mmol), and methanol (8 mL) were added into a flask, and condensed backflow at 60 °C for 16 h. After the reaction was completed, the reaction was cooled to room temperature, and dry column chromatography was performed with dichloromethane as the eluent. The filtrate was collected and rotary evaporated. A small amount of dichloromethane was added to dissolve the solid, which was slowly added to an anhydrous ethanol solution under stirring. The solid was precipitated and washed several times. After filtration and drying, the yellow solid compound C2 was obtained, with a yield of 82%.

[0075] Example 5

[0076] This example provides a long ether chain thiophene copolymer L1, and the synthesis method is as follows:

[0077] Under the nitrogen atmosphere, 2-bromo-3-(2-butoxyethyl) thiophene (0.025 mmol), 2-bromo-3-hexylthiophene (0.475 mmol), potassium carbonate (0.75 mmol), diimine palladium catalyst C1 (0.25 mmol%), pivalic acid (0.15 mmol), dimethylacetamide (4 mL) were reacted at 100°C for 24h, and the long ether chain thiophene copolymer L1 was obtained by precipitation in methanol, with a yield of 66%, HT value of 91%, PDI of 2.61, number average molecular weight Mn of 8.9KDa, and 3-(2-butoxyethyl) thiophene segment accounting for 4.7% of the molar percentage of the long ether chain thiophene copolymer segment, i.e., the copolymerization degree was 4.7 mmol%; the structures of the diimine palladium catalyst C1 and the random long ether chain thiophene copolymer L1 are shown as follows:

[0078]

[0079] wherein x=4.7 mmol%, y=95.3 mmol%.

[0080] Example 6

[0081] This embodiment provides a long ether chain thiophene copolymer L2, and a synthesis method thereof is as follows:

[0082] Under the nitrogen atmosphere, 2-bromo-3-(2-butoxyethyl) thiophene (0.05 mmol), 2-bromo-3-hexylthiophene (0.45 mmol), potassium carbonate (0.75 mmol), diimine palladium catalyst C2 (0.25 mmol%), pivalic acid (0.15 mmol), dimethylacetamide (4 mL) were reacted at 100°C for 24h, and the long ether chain thiophene copolymer L2 was obtained by precipitation in methanol, with a yield of 50%, HT value of 92%, PDI of 2.72, number average molecular weight Mn of 8.3KDa, and 3-(2-butoxyethyl) thiophene segment accounting for 5.6% of the molar percentage of the long ether chain thiophene copolymer segment, i.e., the copolymerization degree was 5.6 mmol%; the structures of the diimine palladium catalyst C2 and the random long ether chain thiophene copolymer L2 are shown as follows:

[0083]

[0084] wherein x=5.6 mmol%, y=94.4 mmol%.

[0085] As can be seen from Examples 5-6, the long ether chain thiophene copolymer of the present application has a random structure, and has the characteristics of high regularity and high molecular weight.

[0086] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above embodiments, and any changes, modifications, substitutions, combinations, simplifications, etc. made without departing from the spirit and principles of the present application should be equivalent replacement manners and should be included in the protection scope of the present application.

Claims

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

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

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

4. Process for the preparation of the diimine palladium complex according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: ligand reaction with (COD)PdCl2to give the corresponding diimine palladium complex.

5. The process according to claim 4, characterized in that, The molar ratio of the ligand to (COD)PdCl2 is 1:1.05-1.

2.

6. The process according to claim 4, characterized in that the process is carried out in the presence of a base. The temperature of the reaction is 50-70℃, and the time is 12-20h.

7. The process according to claim 4, characterized in that, The preparation method of the ligand comprises the following steps: Substituted anilines with acenaphthenequinone reaction, to give the ligand.

8. The process according to claim 7, characterized in that, The molar ratio of the substituted aniline to acenaphthenequinone is 2.05-2.20:

1.

9. The process according to claim 7, characterized in that, The temperature of the reaction is 130-150℃, and the time is 4-7h.

10. The use of the diimine palladium complex of any one of claims 1-3 or the diimine palladium complex prepared by the method of any one of claims 4-9 in the preparation of long ether chain thienyl copolymer.

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