Palladium pyridylaldehyde complex as well as preparation method and application thereof

Abstract

The invention discloses a pyridylaldehyde palladium complex and a preparation method and application thereof, the structural formula of the pyridylaldehyde palladium complex is as shown in formula (I): # imgabs0 # formula (I), R1, R2 and R3 are independently selected from hydrogen or formaldehyde group, and R1, R2 and R3 are not hydrogen at the same time; the pyridylaldehyde palladium complex provided by the invention can be catalytically polymerized at high temperature to prepare the ester thiophene-hexylthiophene copolymer with high molecular weight, high regularity and narrow molecular weight distribution, 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 pyridinecarboxaldehyde palladium complexes, and in particular to a pyridinecarboxaldehyde 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 optoelectronic properties and high hole transport performance, so poly(3-hexylthiophene) (P3HT) has become 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, but P3HT has a higher highest occupied molecular orbital (HOMO) energy level (-4.90eV), resulting in P3HT-based solar cells often having a lower variable output circuit voltage.

[0003] The inventors found in the experiment that the copolymer of ester thiophene and P3HT can increase the variable output voltage while maintaining a high short-circuit current density and fill factor, thereby effectively improving the energy conversion efficiency. However, to date, there are few existing technologies that record catalysts for preparing copolymers of ester thiophene and P3HT. 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 be catalytically polymerized at high temperature to prepare an ester-based 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 pyridine carboxaldehyde palladium complex, the structural formula of the pyridine carboxaldehyde palladium complex is shown in formula (I):

[0006]

[0007] Formula (I)

[0008] Among them, R 1 , R 2 , R 3 are independently selected from hydrogen or formaldehyde, and R 1 , R 2 , R 3 Not hydrogen at the same time.

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

[0010]

[0011] Formula (I)

[0012] Among them, R 1 , R 2 Selected from hydrogen, R 3 Selected from formaldehyde group.

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

[0014]

[0015] Formula (I)

[0016] Among them, R 1 Selected from formaldehyde group, R 2 , R 3 Selected from hydrogen.

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

[0018] Ligand With PdCl 2 Reaction to obtain the pyridine formaldehyde palladium complex.

[0019] In some embodiments of the present invention, the ligand and PdCl 2 The molar ratio 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 ester thiophene-hexyl thiophene copolymer is as shown in formula (I) or formula (II):

[0023]

[0024] Formula (I) Formula (II)

[0025] The molar percentage of the ester-thiophene chain segment in the ester-thiophene-hexylthiophene copolymer chain segment is 2.7% to 20%, and the number average molecular weight of the ester-thiophene-hexylthiophene 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 ester-thiophene-hexylthiophene copolymer, comprising the following steps:

[0029] Under the catalysis of pyridine carboxaldehyde 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 carboxaldehyde palladium complex is shown in formula (I):

[0031]

[0032] Formula (I)

[0033] Among them, R 1 , R 2 , R 3 are independently selected from hydrogen or formaldehyde, and R 1 , R 2 , R 3 Not at the same time hydrogen;

[0034] The bromine-substituted ester-based 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 caproic 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 mole of the bromine-substituted ester thiophene and 2-bromo-3-hexylthiophene to the mole 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 carboxaldehyde palladium complex provided by the present invention can be used to prepare an ester-thiophene-hexylthiophene copolymer at high temperature. The prepared ester-thiophene-hexylthiophene 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 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.

[0050] The pyridine carboxaldehyde palladium complex is prepared by the following reaction route:

[0051]

[0052] In the following examples, the ester thiophene segment content in the ester thiophene-hexyl thiophene copolymer was measured by nuclear magnetic resonance, the ester thiophene-hexyl 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 ester thiophene-hexyl thiophene copolymer was measured by gel permeation chromatography (GPC) with THF 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), PdCl 2 (0.51mmol) and dimethylacetamide (3ml) were added into a 10ml single-mouth bottle respectively, and the reaction was carried out at 80℃ for 0.5h. After the reaction was completed, the mixture was cooled to room temperature and methanol was added for precipitation to obtain a yellow solid compound C1 with a yield of 92%.

[0060] Example 2

[0061] This embodiment provides a pyridine carboxaldehyde palladium complex C2, and its synthesis method is as follows:

[0062] Pyridine-2-carboxaldehyde (1 mmol), PdCl 2 (0.51mmol) and dimethylacetamide (3ml) were added into a 10ml single-mouth bottle respectively, and the reaction was carried out at 80℃ for 0.5h. After the reaction was completed, the mixture was cooled to room temperature and methanol was added for precipitation to obtain a yellow solid compound C2 with a yield of 88%.

[0063] Example 3

[0064] This embodiment provides a pyridine carboxaldehyde palladium complex C3, and its synthesis method is as follows:

[0065] Pyridine-3-carboxaldehyde (1 mmol), PdCl 2(0.51mmol) and dimethylacetamide (3ml) were added into a 10ml single-mouth bottle respectively, and the reaction was carried out at 80℃ for 0.5h. After the reaction was completed, the mixture was cooled to room temperature and methanol was added for precipitation to obtain a yellow solid compound C3 with a yield of 87%.

[0066] Example 4

[0067] This embodiment provides an ester-thiophene-hexylthiophene copolymer L1, and the synthesis method thereof is as follows:

[0068] Under nitrogen atmosphere, 2-bromo-3-(2-acetoxymethyl)thiophene (0.015mmol), 2-bromo-3-hexylthiophene (0.485mmol), potassium carbonate (0.75mmol), pyridine carboxaldehyde palladium complex C1 (0.25mmol%), pivalic acid (0.15mmol), dimethylacetamide (4mL) were reacted at 100°C for 24h, and ester thiophene-hexylthiophene copolymer L1 was obtained by precipitation in methanol. The yield was 77%, the HT value was 88%, the PDI was 2.1, the number average molecular weight Mn was 13.4KDa, and the molar percentage of 3-(2-acetoxymethyl)thiophene segment in the ester thiophene-hexylthiophene copolymer segment was 2.9%, that is, the copolymerization degree was 2.9mmol; the structures of the pyridine carboxaldehyde palladium complex C1 and the ester thiophene-hexylthiophene copolymer L1 are as follows:

[0069]

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

[0071] Example 5

[0072] This embodiment provides an ester-thiophene-hexylthiophene copolymer L2, and the synthesis method thereof is as follows:

[0073] Under nitrogen atmosphere, 2-bromo-3-(2-acetoxymethyl)thiophene (0.125mmol), 2-bromo-3-hexylthiophene (0.375mmol), potassium carbonate (0.75mmol), dipyridine carboxaldehyde palladium catalyst C1 (0.25mmol%), pivalic acid (0.15mmol), dimethylacetamide (4mL) were reacted at 100°C for 24h, and ester thiophene-hexylthiophene copolymer L2 was obtained by precipitation in methanol. The yield was 55%, the HT value was 83%, the PDI was 1.3, the number average molecular weight Mn was 4.7KDa, and the molar percentage of 3-(2-acetoxymethyl)thiophene segment in the ester thiophene-hexylthiophene copolymer segment was 20%, that is, the copolymerization degree was 20mmol; the structures of the dipyridine carboxaldehyde palladium catalyst C1 and the ester thiophene-hexylthiophene copolymer L2 are as follows:

[0074]

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

[0076] Example 6

[0077] This embodiment provides an ester-thiophene-hexylthiophene copolymer L3, and the synthesis method thereof is as follows:

[0078] Under nitrogen atmosphere, 2-bromo-3-(2-acetoxymethyl)thiophene (0.05mmol), 2-bromo-3-hexylthiophene (0.45mmol), potassium carbonate (0.75mmol), pyridine carboxaldehyde palladium complex C2 (0.25mmol%), pivalic acid (0.15mmol), dimethylacetamide (4mL) were reacted at 100°C for 24h, and ester thiophene-hexylthiophene copolymer L3 was obtained by precipitation in methanol. The yield was 75%, the HT value was 90%, the PDI was 1.9, the number average molecular weight Mn was 12.9KDa, and the molar percentage of 3-(2-acetoxymethyl)thiophene segment in the ester thiophene-hexylthiophene copolymer segment was 9.3%, that is, the copolymerization degree was 9.3mmol; the structures of the pyridine carboxaldehyde palladium complex C2 and the ester thiophene-hexylthiophene copolymer L3 are as follows:

[0079]

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

[0081] Example 7

[0082] This embodiment provides an ester-thiophene-hexylthiophene copolymer L4, and the synthesis method thereof is as follows:

[0083] Under nitrogen atmosphere, 2-bromo-3-(2-acetoxymethyl)thiophene (0.045mmol), 2-bromo-3-hexylthiophene (0.455mmol), potassium carbonate (0.75mmol), pyridine carboxaldehyde palladium complex C3 (0.25mmol%), pivalic acid (0.15mmol), dimethylacetamide (4mL) were reacted at 100°C for 24h, and ester thiophene-hexylthiophene copolymer L4 was obtained by precipitation in methanol. The yield was 72%, the HT value was 85%, the PDI was 2.0, the number average molecular weight Mn was 12.5KDa, and the molar percentage of 3-(2-acetoxymethyl)thiophene segment in the ester thiophene-hexylthiophene copolymer segment was 8.4%, that is, the copolymerization degree was 8.4mmol; the structures of the pyridine carboxaldehyde palladium complex C3 and the ester thiophene-hexylthiophene copolymer L4 are shown as follows:

[0084]

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

[0086] Example 8

[0087] This embodiment provides an ester-thiophene-hexylthiophene copolymer L5, and the synthesis method thereof is as follows:

[0088] Under nitrogen atmosphere, 2-bromo-3-(2-acetoxyethyl)thiophene (0.04mmol), 2-bromo-3-hexylthiophene (0.46mmol), potassium carbonate (0.75mmol), pyridine carboxaldehyde palladium complex C1 (0.25mmol%), pivalic acid (0.15mmol), dimethylacetamide (4mL) were reacted at 100°C for 24h, and ester thiophene-hexylthiophene copolymer L5 was obtained by precipitation in methanol. The yield was 81%, the HT value was 92%, the PDI was 2.3, the number average molecular weight Mn was 14.1KDa, and the molar percentage of 3-(2-acetoxyethyl)thiophene segment in the ester thiophene-hexylthiophene copolymer segment was 7.4%, that is, the copolymerization degree was 7.4mmol; the structures of the pyridine carboxaldehyde palladium complex C1 and the ester thiophene-hexylthiophene copolymer L5 are shown as follows:

[0089]

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

[0091] Example 9

[0092] This embodiment provides an ester-thiophene-hexylthiophene copolymer L6, and the synthesis method thereof is as follows:

[0093] Under nitrogen atmosphere, 2-bromo-3-(2-acetoxyethyl)thiophene (0.025mmol), 2-bromo-3-hexylthiophene (0.475mmol), potassium carbonate (0.75mmol), pyridine carboxaldehyde palladium complex C2 (0.25mmol%), pivalic acid (0.15mmol), dimethylacetamide (4mL) were reacted at 100°C for 24h, and ester thiophene-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 13.7KDa, and the molar percentage of 3-(2-acetoxyethyl)thiophene segment in the ester thiophene-hexylthiophene copolymer segment was 4.2%, that is, the copolymerization degree was 4.2mmol; the structures of the pyridine carboxaldehyde palladium complex C2 and the ester thiophene-hexylthiophene copolymer L6 are shown as follows:

[0094]

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

[0096] Example 10

[0097] This embodiment provides an ester-thiophene-hexylthiophene copolymer L7, and the synthesis method thereof is as follows:

[0098] Under nitrogen atmosphere, 2-bromo-3-(2-acetoxyethyl)thiophene (0.015mmol), 2-bromo-3-hexylthiophene (0.485mmol), potassium carbonate (0.75mmol), pyridine carboxaldehyde palladium complex C3 (0.25mmol%), pivalic acid (0.15mmol), dimethylacetamide (4mL) were reacted at 100°C for 24h, and ester thiophene-hexylthiophene copolymer L7 was obtained by precipitation in methanol. The yield was 76%, the HT value was 89%, the PDI was 2.4, the number average molecular weight Mn was 13.1KDa, and the molar percentage of 3-(2-acetoxyethyl)thiophene segment in the ester thiophene-hexylthiophene copolymer segment was 2.7%, that is, the copolymerization degree was 2.7mmol; the structures of the pyridine carboxaldehyde palladium complex C3 and the ester thiophene-hexylthiophene copolymer L7 are shown as follows:

[0099]

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

[0101] It can be seen from Examples 4 to 10 that the ester-thiophene-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 equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A pyridine carboxaldehyde palladium complex, characterized in that The structural formula of the pyridine carboxaldehyde palladium complex is shown in formula (I): Formula (I) Wherein, R1, R2, and R3 are independently selected from hydrogen or formaldehyde, and R1, R2, and R3 are not hydrogen at the same time.

2. The pyridine carboxaldehyde palladium complex according to claim 1, characterized in that The structural formula of the pyridine carboxaldehyde palladium complex is shown in formula (I): Formula (I) Among them, R1 and R2 are selected from hydrogen, and R3 is selected from formaldehyde.

3. The pyridine carboxaldehyde palladium complex according to claim 1, characterized in that The structural formula of the pyridine carboxaldehyde palladium complex is shown in formula (I): Formula (I) Among them, R1 is selected from formaldehyde group, and R2 and R3 are selected from hydrogen.

4. The method for preparing the pyridine carboxaldehyde palladium complex according to any one of claims 1 to 3, characterized in that: The steps include: Ligand The pyridine carboxaldehyde palladium complex is obtained by reacting with PdCl2.

5. The preparation method of the pyridine carboxaldehyde palladium complex according to claim 4, characterized in that: The molar ratio of the ligand to PdCl2 is 1:0.51-0.

55.

6. The preparation method of the pyridine carboxaldehyde palladium complex according to claim 4, characterized in that: The reaction temperature is 70-90°C and the reaction time is 10-50 minutes.

7. Use of the pyridinecarboxaldehyde palladium complex prepared by the preparation method of the pyridinecarboxaldehyde palladium complex according to any one of claims 1 to 3 or the pyridinecarboxaldehyde palladium complex according to any one of claims 4 to 6 in the preparation of esterthiophene-hexylthiophene copolymers.

8. The use according to claim 7, characterized in that: The structure of the ester thiophene-hexyl thiophene copolymer is shown in formula (I) or formula (II): Formula (I) Formula (II) The molar percentage of the ester-thiophene chain segment in the ester-thiophene-hexylthiophene copolymer chain segment is 2.7% to 20%, and the number average molecular weight of the ester-thiophene-hexylthiophene copolymer is 4.7 to 13.8 KDa.

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

5.

10. The use according to claim 7, characterized in that: The esterthiophene-hexylthiophene copolymer is a random copolymer.

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