A pyridine formaldehyde palladium complex and its preparation method and application

Abstract

The present invention discloses a pyridinecarboxaldehyde palladium complex and a preparation method and application thereof. The structural formula of the pyridinecarboxaldehyde palladium complex is shown in formula (I): wherein R1, R2, and R3 are independently selected from hydrogen or formaldehyde groups, and R1, R2, and R3 are not hydrogen at the same time; the pyridinecarboxaldehyde palladium complex provided by the present invention can be catalytically polymerized at high temperature to prepare an ester-thiophene-hexylthiophene copolymer with high molecular weight, high regularity and narrow molecular weight distribution, and has broad application prospects in the fields of solar cells, organic transistors, electrochromic devices, chemical sensors, electromagnetic shielding materials, etc.

Description

Technical Field

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

[0002] Poly(3-hexylthiophene) is a polythiophene derivative with excellent stability and solution coating properties. It also possesses unique optoelectronic properties and high hole transport performance, making it one of the most commonly used polymer hole transport materials. Due to its excellent carrier mobility and low-cost manufacturing, poly(3-hexylthiophene) (P3HT) is often used to prepare hole transport layer materials. However, P3HT has a high highest occupied molecular orbital (HOMO) energy level (-4.90 eV), resulting in P3HT-based solar cells often having a low variable output circuit voltage.

[0003] During their experiments, the inventors discovered that copolymerizing esterthiophene with P3HT can increase the variable output voltage while maintaining a high short-circuit current density and fill factor, thereby effectively improving energy conversion efficiency. However, to date, there are few existing documents documenting catalysts for preparing esterthiophene-P3HT copolymers. Summary of the Invention

[0004] The object of the present invention is to overcome the defects and shortcomings of the prior art and provide a pyridine carboxaldehyde palladium complex, which can catalyze polymerization at high temperature to produce an ester-thiophene-hexylthiophene copolymer with high molecular weight, high regularity and narrow molecular weight distribution.

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

[0006]

[0007] Formula (I)

[0008] Wherein, R1, R2, and R3 are independently selected from hydrogen or formaldehyde, and R1, R2, and R3 are not hydrogen at the same time.

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

[0010]

[0011] Formula (I)

[0012] Wherein, R1 and R2 are selected from hydrogen, and R3 is selected from formaldehyde.

[0013] In some embodiments of the present invention, the structural formula of the pyridine formaldehyde palladium complex is shown in formula (I):

[0014]

[0015] Formula (I)

[0016] Wherein, R1 is selected from formaldehyde group, and R2 and R3 are selected from hydrogen.

[0017] Another object of the present invention is to provide a method for preparing the pyridinecarboxaldehyde palladium complex, comprising the steps of:

[0018] ligand The product is reacted with PdCl2 to obtain the pyridine formaldehyde palladium complex.

[0019] In some embodiments of the present invention, the molar ratio of the ligand to PdCl2 is 1:0.51~0.55.

[0020] In some embodiments of the present invention, the reaction temperature is 70-90° C., and the reaction time is 10-50 min.

[0021] Another object of the present invention is to provide the use of the pyridinecarboxaldehyde palladium complex or the pyridinecarboxaldehyde palladium complex prepared by the preparation method of the pyridinecarboxaldehyde palladium complex in the preparation of esterthiophene-hexylthiophene copolymers.

[0022] In some embodiments of the present invention, the structure of the esterthiophene-hexylthiophene copolymer is as shown in formula (I) or formula (II):

[0023]

[0024] Formula (I) Formula (II)

[0025] The molar percentage of the ester-thiophene segment in the ester-thiophene-hexyl-thiophene copolymer segment is 2.7% to 20%, and the number average molecular weight of the ester-thiophene-hexyl-thiophene copolymer is 4.7 to 13.8 KDa.

[0026] In some embodiments of the present invention, the HT value of the esterthiophene-hexylthiophene copolymer is ≥80%, and the PDI is ≤2.5.

[0027] In some embodiments of the present invention, the esterthiophene-hexylthiophene copolymer is a random copolymer.

[0028] Another object of the present invention is to provide a method for preparing an esterthiophene-hexylthiophene copolymer, comprising the following steps:

[0029] Under the catalysis of pyridine formaldehyde palladium catalyst, the bromine-substituted ester thiophene and 2-bromo-3-hexylthiophene react to obtain the ester thiophene-hexylthiophene copolymer;

[0030] The structural formula of the pyridine formaldehyde palladium complex is shown in formula (I):

[0031]

[0032] Formula (I)

[0033] wherein R1, R2, and R3 are independently selected from hydrogen or formaldehyde, and R1, R2, and R3 are not hydrogen at the same time;

[0034] The bromine-substituted ester thiophene is selected from at least one of 2-bromo-3-(2-acetoxyethyl)thiophene and 2-bromo-3-(2-acetoxymethyl)thiophene.

[0035] In some embodiments of the present invention, the molar ratio of the bromine-substituted ester thiophene to 2-bromo-3-hexylthiophene is 3-25:75-97.

[0036] In some embodiments of the present invention, the ratio of the total mole of the bromine-substituted ester thiophene and 2-bromo-3-hexylthiophene to the mole of the palladium catalyst is 1:0.001-0.01.

[0037] In some embodiments of the present invention, the reaction temperature is 80-120° C., and the reaction time is 12-36 hours.

[0038] In some embodiments of the present invention, the reaction further contains an inorganic base, an organic acid and a solvent.

[0039] In some embodiments of the present invention, the inorganic base includes at least one of potassium carbonate and sodium carbonate.

[0040] In some embodiments of the present invention, the organic acid includes at least one of pivalic acid and hexanoic acid.

[0041] In some embodiments of the present invention, the solvent includes N,N-dimethylacetamide.

[0042] In some embodiments of the present invention, the ratio of the total mole of the bromine-substituted ester thiophene and 2-bromo-3-hexylthiophene to the mole of the inorganic base is 1-1.5:1-1.5.

[0043] In some embodiments of the present invention, the ratio of the total moles of the bromine-substituted ester thiophene and 2-bromo-3-hexylthiophene to the moles of the organic acid is 2.5-4.5:1.

[0044] In some embodiments of the present invention, after the reaction is completed, a purification step is further included.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The pyridine formaldehyde palladium complex provided by the present invention can be used to prepare an ester thiophene-hexyl thiophene copolymer at high temperature. The prepared ester thiophene-hexyl thiophene copolymer has the advantages of high molecular weight, high regularity and narrow molecular weight distribution, has obvious economic benefits, and has broad application prospects in the fields of solar cells, organic transistors, electrochromic devices, chemical sensors, electromagnetic shielding materials, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is the H NMR spectrum of the pyridinecarboxaldehyde palladium complex C1 provided in Example 1.

[0048] Figure 2 This is the H NMR spectrum of the pyridinecarboxaldehyde palladium complex C2 provided in Example 2. DETAILED DESCRIPTION

[0049] The following will clearly and completely describe the concept of the present invention and the technical effects produced in conjunction with the embodiments, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the embodiments described 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 those skilled in the art without creative work are 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.

[0050] The pyridine formaldehyde palladium complex was prepared by the following reaction route:

[0051]

[0052] In the following examples, the esterthiophene segment content in the esterthiophene-hexylthiophene copolymer was determined by nuclear magnetic resonance spectroscopy. The esterthiophene-hexylthiophene copolymer was dissolved in deuterated chloroform, TMS was used as the internal standard, and the measurement temperature was 25°C. The molecular weight or degree of polymerization of the esterthiophene-hexylthiophene copolymer was determined by gel permeation chromatography (GPC) using THF as the mobile phase. Wherein, HT and HT values ​​represent isotacticity, and PDI represents molecular weight distribution index;

[0053] The structural formula of 2-bromo-3-(2-acetoxymethyl)thiophene is as follows:

[0054] ;

[0055] The structural formula of 2-bromo-3-(2-acetoxyethyl)thiophene is as follows:

[0056] .

[0057] Example 1

[0058] This embodiment provides a pyridine carboxaldehyde palladium complex C1, and its synthesis method is as follows:

[0059] 4-Pyridinecarboxaldehyde (1 mmol), PdCl2 (0.51 mmol), and dimethylacetamide (3 ml) were added separately into a 10 ml single-necked bottle and reacted at 80°C for 0.5 h. After the reaction, the mixture was cooled to room temperature and methanol was added to precipitate the solid to obtain yellow solid compound C1 with a yield of 92%.

[0060] Example 2

[0061] This embodiment provides a pyridine carboxaldehyde palladium complex C2, the synthesis method of which is as follows:

[0062] Pyridine-2-carboxaldehyde (1 mmol), PdCl2 (0.51 mmol), and dimethylacetamide (3 ml) were added into a 10 ml single-necked bottle, and the mixture was reacted at 80°C for 0.5 h. After the reaction, the mixture was cooled to room temperature and methanol was added to precipitate the solid to obtain yellow solid compound C2 with a yield of 88%.

[0063] Example 3

[0064] This embodiment provides a pyridine carboxaldehyde palladium complex C3, the synthesis method of which is as follows:

[0065] Pyridine-3-carboxaldehyde (1 mmol), PdCl2 (0.51 mmol), and dimethylacetamide (3 ml) were added into a 10 ml single-necked bottle, and the mixture was reacted at 80°C for 0.5 h. After the reaction, the mixture was cooled to room temperature and methanol was added to precipitate the solid to obtain yellow solid compound C3 with a yield of 87%.

[0066] Example 4

[0067] This embodiment provides an ester thiophene-hexyl thiophene copolymer L1, the synthesis method of which is as follows:

[0068] Under a nitrogen atmosphere, 2-bromo-3-(2-acetoxymethyl)thiophene (0.015 mmol), 2-bromo-3-hexylthiophene (0.485 mmol), potassium carbonate (0.75 mmol), pyridinecarboxaldehyde palladium complex C1 (0.25 mmol%), pivalic acid (0.15 mmol), and dimethylacetamide (4 mL) were reacted at 100° C. for 24 h, and precipitated in methanol to obtain an esterthiophene-hexylthiophene copolymer L1 with a yield of 77%, an HT value of 88%, a PDI of 2.1, a number average molecular weight Mn of 13.4 KDa, and a molar percentage of 3-(2-acetoxymethyl)thiophene segments in the esterthiophene-hexylthiophene copolymer segments of 2.9%, i.e., a degree of copolymerization of 2.9 mmol). The structures of the pyridinecarboxaldehyde palladium complex C1 and the esterthiophene-hexylthiophene copolymer L1 are shown below:

[0069]

[0070] Among them, x=2.9mmol%, y=97.1mmol%.

[0071] Example 5

[0072] This embodiment provides an ester thiophene-hexyl thiophene copolymer L2, the synthesis method of which is as follows:

[0073] Under a nitrogen atmosphere, 2-bromo-3-(2-acetoxymethyl)thiophene (0.125 mmol), 2-bromo-3-hexylthiophene (0.375 mmol), potassium carbonate (0.75 mmol), dipyridinecarboxaldehyde palladium catalyst C1 (0.25 mmol%), pivalic acid (0.15 mmol), and dimethylacetamide (4 mL) were reacted at 100° C. for 24 h, and precipitated in methanol to obtain an ester thiophene-hexylthiophene copolymer L2 with a yield of 55%, an HT value of 83%, a PDI of 1.3, a number average molecular weight Mn of 4.7 KDa, and a mole percentage of 3-(2-acetoxymethyl)thiophene segments in the ester thiophene-hexylthiophene copolymer segments of 20%, i.e., a degree of copolymerization of 20 mmol). The structures of the dipyridinecarboxaldehyde palladium catalyst C1 and the ester thiophene-hexylthiophene copolymer L2 are shown below:

[0074]

[0075] Among them, x=20mmol%, y=80mmol%.

[0076] Example 6

[0077] This embodiment provides an esterthiophene-hexylthiophene copolymer L3, the synthesis method of which is as follows:

[0078] Under a nitrogen atmosphere, 2-bromo-3-(2-acetoxymethyl)thiophene (0.05 mmol), 2-bromo-3-hexylthiophene (0.45 mmol), potassium carbonate (0.75 mmol), pyridinecarboxaldehyde palladium complex C2 (0.25 mmol%), pivalic acid (0.15 mmol), and dimethylacetamide (4 mL) were reacted at 100° C. for 24 h, and precipitated in methanol to obtain an esterthiophene-hexylthiophene copolymer L3 with a yield of 75%, an HT value of 90%, a PDI of 1.9, a number average molecular weight Mn of 12.9 KDa, and a molar percentage of 3-(2-acetoxymethyl)thiophene segments in the esterthiophene-hexylthiophene copolymer segments of 9.3%, i.e., a degree of copolymerization of 9.3 mmol). The structures of the pyridinecarboxaldehyde palladium complex C2 and the esterthiophene-hexylthiophene copolymer L3 are shown below:

[0079]

[0080] Among them, x=9.3mmol%, y=90.7mmol%.

[0081] Example 7

[0082] This embodiment provides an ester thiophene-hexyl thiophene copolymer L4, the synthesis method of which is as follows:

[0083] Under a nitrogen atmosphere, 2-bromo-3-(2-acetoxymethyl)thiophene (0.045 mmol), 2-bromo-3-hexylthiophene (0.455 mmol), potassium carbonate (0.75 mmol), pyridinecarboxaldehyde palladium complex C3 (0.25 mmol%), pivalic acid (0.15 mmol), and dimethylacetamide (4 mL) were reacted at 100° C. for 24 h, and precipitated in methanol to obtain an esterthiophene-hexylthiophene copolymer L4 with a yield of 72%, an HT value of 85%, a PDI of 2.0, a number average molecular weight Mn of 12.5 KDa, and an 8.4% mole percentage of 3-(2-acetoxymethyl)thiophene segments in the esterthiophene-hexylthiophene copolymer segments, i.e., a degree of copolymerization of 8.4 mmol). The structures of the pyridinecarboxaldehyde palladium complex C3 and the esterthiophene-hexylthiophene copolymer L4 are shown below:

[0084]

[0085] Among them, x=8.4mmol%, y=91.6mmol%.

[0086] Example 8

[0087] This embodiment provides an ester thiophene-hexyl thiophene copolymer L5, the synthesis method of which is as follows:

[0088] Under a nitrogen atmosphere, 2-bromo-3-(2-acetoxyethyl)thiophene (0.04 mmol), 2-bromo-3-hexylthiophene (0.46 mmol), potassium carbonate (0.75 mmol), pyridinecarboxaldehyde palladium complex C1 (0.25 mmol%), pivalic acid (0.15 mmol), and dimethylacetamide (4 mL) were reacted at 100° C. for 24 h, and precipitated in methanol to obtain an esterthiophene-hexylthiophene copolymer L5 with a yield of 81%, an HT value of 92%, a PDI of 2.3, a number average molecular weight Mn of 14.1 KDa, and a molar percentage of 3-(2-acetoxyethyl)thiophene segments in the esterthiophene-hexylthiophene copolymer segments of 7.4%, i.e., a degree of copolymerization of 7.4 mmol). The structures of the pyridinecarboxaldehyde palladium complex C1 and the esterthiophene-hexylthiophene copolymer L5 are shown below:

[0089]

[0090] Among them, x=7.4mmol%, y=92.6mmol%.

[0091] Example 9

[0092] This embodiment provides an ester thiophene-hexyl thiophene copolymer L6, the synthesis method of which is as follows:

[0093] Under a nitrogen atmosphere, 2-bromo-3-(2-acetoxyethyl)thiophene (0.025 mmol), 2-bromo-3-hexylthiophene (0.475 mmol), potassium carbonate (0.75 mmol), pyridinecarboxaldehyde palladium complex C2 (0.25 mmol%), pivalic acid (0.15 mmol), and dimethylacetamide (4 mL) were reacted at 100° C. for 24 h, and esterthiophene-hexylthiophene copolymer L6 was obtained by precipitation in methanol. The yield was 79%, the HT value was 90%, the PDI was 2.2, the number average molecular weight Mn was 13.7 KDa, and the mole percentage of 3-(2-acetoxyethyl)thiophene segments in the esterthiophene-hexylthiophene copolymer segments was 4.2%, that is, the degree of copolymerization was 4.2 mmol. The structures of the pyridinecarboxaldehyde palladium complex C2 and the esterthiophene-hexylthiophene copolymer L6 are shown below:

[0094]

[0095] Among them, x=4.2mmol%, y=95.8mmol%.

[0096] Example 10

[0097] This embodiment provides an ester thiophene-hexyl thiophene copolymer L7, the synthesis method of which is as follows:

[0098] Under a nitrogen atmosphere, 2-bromo-3-(2-acetoxyethyl)thiophene (0.015 mmol), 2-bromo-3-hexylthiophene (0.485 mmol), potassium carbonate (0.75 mmol), pyridinecarboxaldehyde palladium complex C3 (0.25 mmol%), pivalic acid (0.15 mmol), and dimethylacetamide (4 mL) were reacted at 100°C for 24 h, and precipitated in methanol to obtain an esterthiophene-hexylthiophene copolymer L7 with a yield of 76%, an HT value of 89%, a PDI of 2.4, a number average molecular weight Mn of 13.1 KDa, and a mole percentage of 3-(2-acetoxyethyl)thiophene segments in the esterthiophene-hexylthiophene copolymer segments of 2.7%, i.e., a degree of copolymerization of 2.7 mmol). The structures of the pyridinecarboxaldehyde palladium complex C3 and the esterthiophene-hexylthiophene copolymer L7 are shown below:

[0099]

[0100] Among them, x=2.7mmol%, y=97.3mmol%.

[0101] It can be seen from Examples 4 to 10 that the esterthiophene-hexylthiophene copolymer of the present invention has a random structure and has the characteristics of high regularity, high molecular weight and narrow molecular weight distribution.

[0102] 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 considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A pyridinecarboxaldehyde palladium complex, characterized in that The structural formula of the pyridine formaldehyde palladium complex is shown in formula (I): Formula (I) Wherein, R1 and R2 are selected from hydrogen, and R3 is selected from formaldehyde; or R1 and R3 are selected from hydrogen, and R2 is selected from formaldehyde.

2. The preparation method of the pyridinecarboxaldehyde palladium complex according to claim 1, wherein The steps include: ligand The product is reacted with PdCl2 to obtain the pyridine formaldehyde palladium complex.

3. The preparation method of the pyridinecarboxaldehyde palladium complex according to claim 2, wherein The molar ratio of the ligand to PdCl2 is 1:0.51-0.

55.

4. The preparation method of the pyridinecarboxaldehyde palladium complex according to claim 2, wherein The reaction temperature is 70-90° C. and the reaction time is 10-50 min.

5. Use of the pyridinecarboxaldehyde palladium complex according to claim 1 or the pyridinecarboxaldehyde palladium complex prepared by the preparation method of the pyridinecarboxaldehyde palladium complex according to any one of claims 2 to 4 in the preparation of an esterthiophene-hexylthiophene copolymer.

6. The use according to claim 5, characterized in that The structure of the esterthiophene-hexylthiophene copolymer is shown in formula (I) or formula (II): Formula (I) Formula (II) The molar percentage of the ester-thiophene segment in the ester-thiophene-hexyl-thiophene copolymer segment is 2.7% to 20%, and the number average molecular weight of the ester-thiophene-hexyl-thiophene copolymer is 4.7 to 13.8 KDa.

7. The use according to claim 5, characterized in that The HT value of the esterthiophene-hexylthiophene copolymer is ≥80%, and the PDI is ≤2.

5.

8. The use according to claim 5, characterized in that The esterthiophene-hexylthiophene copolymer is a random copolymer.

Images