An ester-substituted palladium complex, its preparation method and application

Abstract

The application discloses an ester-substituted palladium complex and a preparation method and application thereof, and a structural formula of the ester-substituted palladium complex is shown as formula (I): wherein R1, R2 and R3 are independently selected from hydrogen or a methyl formate group, and R1, R2 and R3 are not hydrogen at the same time. The ester-substituted palladium complex provided by the application can be used for catalyzing polymerization at high temperature to obtain an ester-based thiophene-hexyl thiophene copolymer with high molecular weight and high regularity, 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 present application relates to the technical field of ester-substituted palladium complexes, in particular to an ester-substituted palladium complex and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of optoelectronic material research, thienyl copolymers have been widely concerned due to their good stability after doping and easy modification. Although the synthesis of thienyl polymers has a long history, early thienyl copolymers were used in LED and polymer solar cell devices, and the molecular structure design was also to meet the requirements of LED and polymer solar cell devices. Perovskite solar cells have developed for only about ten years, and most of the early thienyl copolymers do not meet the requirements of perovskite solar cell devices in terms of energy level, solubility and heat resistance. Therefore, designing new thienyl copolymers that meet the special requirements of perovskite solar cell devices is an urgent problem to be solved.

[0003] The homopolymer of monomer 3-alkoxythiophene has a HOMO energy level that meets the requirements (-5.19 eV) and good solubility. The energy level of P3HT is best matched with perovskite solar cells (-5.20 eV), and P3HT is a polymer material commonly used in the hole transport layer of perovskite solar cells at present, but its solubility is generally (0.1 mg / mL), which is far inferior to the traditional hole transport material small molecule spiro-OMeTAD, to some extent, limiting the application of P3HT.

[0004] The inventors found during experiments that copolymerizing ester thiophene with P3HT can improve the solubility of P3HT to some extent. However, so far, there is little prior art that describes a catalyst for preparing ester thiophene and P3HT copolymer. SUMMARY

[0005] The present application aims to overcome the defects and shortcomings of the prior art, and provides an ester-substituted palladium complex, which can catalyze the polymerization of ester thiophene-hexyl thiophene copolymer at high temperature to obtain high molecular weight and high regularity.

[0006] The present application aims to provide an ester-substituted palladium complex, and the structural formula of the ester-substituted palladium complex is shown as formula (I):

[0007]

[0008] Formula (I)

[0009] wherein R1, R2, R3 are independently selected from hydrogen or methyl formate group, and R1, R2, R3 are not hydrogen at the same time.

[0010] In some embodiments of the present application, the ester-substituted palladium complex has a structure as shown in formula (I):

[0011]

[0012] Formula (I)

[0013] wherein R1 and R3 are selected from hydrogen, and R2 is selected from methyl formate.

[0014] In some embodiments of the present application, the ester-substituted palladium complex has a structure as shown in formula (I):

[0015]

[0016] Formula (I)

[0017] wherein R1 and R2 are selected from methyl formate, and R3 is selected from hydrogen.

[0018] Another object of the present application is to provide a preparation method of the ester-substituted palladium complex, comprising the following steps:

[0019] Ligand reacting with (COD)PdCl2 to obtain the ester-substituted palladium complex;

[0020] wherein R1, R2 and R3 are independently selected from hydrogen or methyl formate, and R1, R2 and R3 are not hydrogen at the same time.

[0021] In some embodiments of the present application, the molar ratio of the ligand to PdCl2 is 1:0.51-0.55.

[0022] In some embodiments of the present application, the reaction temperature is 60-100℃, and the reaction time is 20-50 min.

[0023] Another object of the present application is to provide an application of the ester-substituted palladium complex or the ester-substituted palladium complex prepared by the preparation method of the ester-substituted palladium complex in preparing an ester-substituted thiophene-hexyl thiophene copolymer.

[0024] In some embodiments of the present application, the ester-substituted thiophene-hexyl thiophene copolymer has a structure as shown in formula (II) or formula (III):

[0025]

[0026] Formula (II) Formula (III)

[0027] The ester-thiophene chain segment accounts for 2.6% to 13.9% of the ester-thiophene-hexyl-thiophene copolymer chain segment, and the number average molecular weight of the ester-thiophene-hexyl-thiophene copolymer is 9.3 to 17.3 KDa.

[0028] In some embodiments of the present application, the HT value of the ester-thiophene-hexyl-thiophene copolymer is greater than or equal to 80%.

[0029] In some embodiments of the present application, the ester-thiophene-hexyl-thiophene copolymer is a random copolymer.

[0030] Another object of the present application is to provide a preparation method of an ester-thiophene-hexyl-thiophene copolymer, comprising the following steps:

[0031] The ester-thiophene-hexyl-thiophene copolymer is obtained by reacting 2-bromo-3-ester-thiophene and 2-bromo-3-hexyl-thiophene under the catalysis of a palladium complex substituted with an ester group;

[0032] The structure of the palladium complex substituted with an ester group is shown in formula (I):

[0033]

[0034] Formula (I)

[0035] R1, R2, and R3 are independently selected from hydrogen or methyl formate group, and R1, R2, and R3 are not hydrogen at the same time.

[0036] The 2-bromo-3-ester-thiophene is selected from at least one of 2-bromo-3-(2-acetyloxyethyl)thiophene and 2-bromo-3-(2-acetyloxymethyl)thiophene.

[0037] In some embodiments of the present application, the molar ratio of the 2-bromo-3-ester-thiophene to the 2-bromo-3-hexyl-thiophene is 3 to 25: 75 to 97.

[0038] In some embodiments of the present application, the ratio of the total moles of the 2-bromo-3-ester-thiophene and the 2-bromo-3-hexyl-thiophene to the moles of the palladium complex substituted with an ester group is 1:0.001 to 0.01.

[0039] In some embodiments of the present application, the reaction temperature is 80 to 120°C, and the reaction time is 12 to 36 hours.

[0040] In some embodiments of the present application, the reaction further contains an inorganic base, an organic acid, and a solvent.

[0041] In some embodiments of the present application, the inorganic base includes at least one of potassium carbonate and sodium carbonate.

[0042] In some embodiments of the present application, the organic acid comprises at least one of pivalic acid and hexanoic acid.

[0043] In some embodiments of the present application, the solvent comprises N,N-dimethylacetamide.

[0044] In some embodiments of the present application, the ratio of the total moles of 2-bromo-3-ester-thiophene and 2-bromo-3-hexyl-thiophene to the moles of inorganic base is 1-1.5:1-1.5.

[0045] In some embodiments of the present application, the ratio of the total moles of 2-bromo-3-ester-thiophene and 2-bromo-3-hexyl-thiophene to the moles of organic acid is 2.5-4.5:1.

[0046] In some embodiments of the present application, after the reaction is completed, a purification step is further included.

[0047] Compared with the prior art, the present application has the following beneficial effects:

[0048] The ester-substituted palladium complex provided by the present application can be used to prepare an ester-thiophene-hexyl-thiophene copolymer at high temperature, and the ester-thiophene-hexyl-thiophene copolymer prepared has the advantages of high molecular weight and high regularity, has obvious economic benefits, and has a wide application prospect in the fields of solar cells, organic transistors, electrochromic devices, chemical sensors, electromagnetic shielding materials, etc. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 The nuclear magnetic hydrogen spectrum of the ester-substituted palladium complex C2 provided for Example 1. DETAILED DESCRIPTION

[0050] The concept and technical effects of the present application will be described in detail below in combination with examples, so as to fully understand the purpose, features and effects of the present application. Obviously, the described examples are only a part of the examples of the present application, but not all the examples. Based on the examples of the present application, other examples obtained by those skilled in the art without creative labor are within the protection scope of the present application. If no special description is made in the examples, the used test methods are all conventional methods; if no special description is made, the used materials, reagents, etc. can be obtained from commercial reagents and materials.

[0051] The ester-substituted palladium complex is prepared by the following reaction route:

[0052]

[0053] In the following examples, the content of the ester-thiophene segment in the ester-thiophene-hexylthiophene copolymer is determined by a nuclear magnetic resonance instrument. The ester-thiophene-hexylthiophene copolymer is dissolved in deuterated chloroform, and TMS is used as an internal standard. The determination temperature is 25°C. The molecular weight or the degree of polymerization of the ester-thiophene-hexylthiophene copolymer is determined by a THF mobile phase gel permeation chromatograph (GPC). Among them, HT and HT values represent isotacticity, and PDI represents a molecular weight distribution index.

[0054] The structural formula of 2-bromo-3-(2-acetyloxymethyl)thiophene is as follows:

[0055] ;

[0056] The structural formula of 2-bromo-3-(2-acetyloxyethyl)thiophene is as follows:

[0057] .

[0058] Example 1

[0059] This example provides an ester-substituted palladium complex C1, and the synthesis method thereof is as follows:

[0060] Methyl 2-aminobenzoate (1 mmol), (COD)PdCl2 (0.51 mmol), and dimethylacetamide (3 ml) are respectively added to 10 ml single-neck flasks, and reacted at 80°C for 0.5 h. After the reaction is completed, the temperature is cooled to room temperature, methanol is added for precipitation, and the solid is dissolved and subjected to a silica gel chromatographic column. After drying, recrystallization (absolute ethanol) is performed, and the product is filtered and dried to obtain yellow solid compound C1 with a yield of 83%.

[0061] Example 2

[0062] This example provides an ester-substituted palladium complex C2, and the synthesis method thereof is as follows:

[0063] Methyl 2-aminobenzoate (1 mmol), (COD)PdCl2 (0.51 mmol), and dimethylacetamide (3 ml) are respectively added to 10 ml single-neck flasks, and reacted at 80°C for 0.5 h. After the reaction is completed, the temperature is cooled to room temperature, methanol is added for precipitation, and the solid is dissolved and subjected to a silica gel chromatographic column. After drying, recrystallization (absolute ethanol) is performed, and the product is filtered and dried to obtain yellow solid compound C2 with a yield of 79%.

[0064] Example 3

[0065] This example provides an ester-substituted palladium complex C3, and the synthesis method thereof is as follows:

[0066] Methyl 4-aminobenzoate (1 mmol), (COD)PdCl2(0.51 mmol), dimethylacetamide (3 ml) were added into 10 ml single-mouth bottles respectively, and reacted at 80°C for 0.5 h. After the reaction, the mixture was cooled to room temperature, methanol was added for precipitation, and the precipitated solid was dissolved and subjected to silica gel column chromatography. After drying, recrystallization (absolute ethanol) and filtration, a yellow solid compound C3 was obtained in a yield of 89%.

[0067] Example 4

[0068] This example provides an ester-thiophene-hexylthiophene copolymer L1, and a synthesis method thereof is as follows:

[0069] Under a nitrogen atmosphere, 2-bromo-3-(2-acetyloxymethyl)thiophene (0.015 mmol), 2-bromo-3-hexylthiophene (0.485 mmol), potassium carbonate (0.75 mmol), ester-substituted palladium complex C1 (0.25 mmol%), pivalic acid (0.15 mmol), dimethylacetamide (4 mL) were reacted at 100°C for 24 h. The ester-thiophene-hexylthiophene copolymer L1 was precipitated in methanol, and the yield was 74%, the HT value was 90%, the PDI was 3.0, the number average molecular weight Mn was 15.9 KDa, the 3-(2-acetyloxymethyl)thiophene segment accounted for 3.4% of the molar percentage of the ester-thiophene-hexylthiophene copolymer segment, i.e., the copolymerization degree was 3.4 mmol%, and the structures of the ester-substituted palladium complex C1 and the ester-thiophene-hexylthiophene copolymer L1 are as follows:

[0070]

[0071] wherein x = 3.4 mmol%, y = 96.6 mmol%.

[0072] Example 5

[0073] This example provides an ester-thiophene-hexylthiophene copolymer L2, and a synthesis method thereof is as follows:

[0074] Under nitrogen atmosphere, 2-bromo-3-(2-acetyloxymethyl)thiophene (0.125 mmol), 2-bromo-3-hexylthiophene (0.375 mmol), potassium carbonate (0.75 mmol), ester-substituted palladium complex C1 (0.25 mmol%), pivalic acid (0.15 mmol), dimethylacetamide (4 mL) were reacted at 100°C for 24 h, and the ester-thiophene-hexylthiophene copolymer L2 was precipitated in methanol with a yield of 61%, HT value of 84%, PDI of 2.4, number average molecular weight Mn of 9.3 KDa, and 3-(2-acetyloxymethyl)thiophene segment accounting for 13.9% of the molar percentage of the ester-thiophene-hexylthiophene copolymer segment, i.e. copolymerization degree of 13.9 mmol%; the structures of the ester-substituted palladium complex C1 and the ester-thiophene-hexylthiophene copolymer L2 are shown as follows:

[0075]

[0076] wherein x = 13.9 mmol%, y = 86.1 mmol%.

[0077] Example 6

[0078] This example provides an ester-thiophene-hexylthiophene copolymer L3, and the synthesis method thereof is as follows:

[0079] Under nitrogen atmosphere, 2-bromo-3-(2-acetyloxymethyl)thiophene (0.015 mmol), 2-bromo-3-hexylthiophene (0.485 mmol), potassium carbonate (0.75 mmol), ester-substituted palladium complex C2 (0.25 mmol%), pivalic acid (0.15 mmol), dimethylacetamide (4 mL) were reacted at 100°C for 24 h, and the ester-thiophene-hexylthiophene copolymer L3 was precipitated in methanol with a yield of 72%, HT value of 93%, PDI of 3.2, number average molecular weight Mn of 17.3 KDa, and 3-(2-acetyloxymethyl)thiophene segment accounting for 4.1% of the molar percentage of the ester-thiophene-hexylthiophene copolymer segment, i.e. copolymerization degree of 4.1 mmol%; the structures of the ester-substituted palladium complex C2 and the ester-thiophene-hexylthiophene copolymer L3 are shown as follows:

[0080]

[0081] wherein x = 4.1 mmol%, y = 95.9 mmol%.

[0082] Example 7

[0083] This example provides an ester-thiophene-hexylthiophene copolymer L4, and the synthesis method thereof is as follows:

[0084] Under nitrogen atmosphere, 2-bromo-3-(2-acetyloxymethyl)thiophene (0.015 mmol), 2-bromo-3-hexylthiophene (0.485 mmol), potassium carbonate (0.75 mmol), ester-substituted palladium complex C3 (0.25 mmol%), pivalic acid (0.15 mmol), dimethylacetamide (4 mL) were reacted at 100°C for 24 h, and the ester-thiophene-hexylthiophene copolymer L4 was obtained by precipitation in methanol with a yield of 78%, HT value of 89%, PDI of 2.9, number average molecular weight Mn of 13.8 KDa, and 3-(2-acetyloxymethyl)thiophene segment accounting for 2.6% of the molar percentage of the ester-thiophene-hexylthiophene copolymer segment, i.e., the copolymerization degree was 2.6 mmol%. The structures of the ester-substituted palladium complex C3 and the ester-thiophene-hexylthiophene copolymer L4 are shown below:

[0085]

[0086] wherein x = 2.6 mmol%, y = 97.4 mmol%.

[0087] Example 8

[0088] This example provides an ester-thiophene-hexylthiophene copolymer L5, and the synthesis method thereof is as follows:

[0089] Under nitrogen atmosphere, 2-bromo-3-(2-acetyloxymethyl)thiophene (0.015 mmol), 2-bromo-3-hexylthiophene (0.485 mmol), potassium carbonate (0.75 mmol), ester-substituted palladium complex C3 (0.25 mmol%), pivalic acid (0.15 mmol), dimethylacetamide (4 mL) were reacted at 100°C for 24 h, and the ester-thiophene-hexylthiophene copolymer L4 was obtained by precipitation in methanol with a yield of 78%, HT value of 89%, PDI of 2.9, number average molecular weight Mn of 13.8 KDa, and 3-(2-acetyloxymethyl)thiophene segment accounting for 2.6% of the molar percentage of the ester-thiophene-hexylthiophene copolymer segment, i.e., the copolymerization degree was 2.6 mmol%. The structures of the ester-substituted palladium complex C3 and the ester-thiophene-hexylthiophene copolymer L4 are shown below:

[0090]

[0091] wherein x = 2.6 mmol%, y = 97.4 mmol%.

[0092] Example 9

[0093] This example provides an ester-thiophene-hexylthiophene copolymer L5, and the synthesis method thereof is as follows:

[0094] Under the nitrogen atmosphere, 2-bromo-3-(2-acetyloxyethyl)thiophene (0.03 mmol), 2-bromo-3-hexylthiophene (0.47 mmol), potassium carbonate (0.75 mmol), ester-substituted palladium complex C2 (0.25 mmol%), pivalic acid (0.15 mmol), dimethylacetamide (4 mL) were reacted at 100°C for 24 h, and the ester-thiophene-hexylthiophene copolymer L6 was obtained by precipitation in methanol, with a yield of 76%, HT value of 88%, PDI of 3.2, number average molecular weight Mn of 13.9 KDa, and 3-(2-acetyloxyethyl)thiophene segment accounting for 4.4% of the molar percentage of the ester-thiophene-hexylthiophene copolymer segment, i.e., the copolymerization degree is 4.4 mmol%; the structures of the ester-substituted palladium complex C2 and the ester-thiophene-hexylthiophene copolymer L6 are shown as follows:

[0095]

[0096] wherein x = 4.4 mmol%, y = 95.6 mmol%.

[0097] Example 10

[0098] The present embodiment provides an ester-thiophene-hexylthiophene copolymer L7, and a synthesis method thereof is as follows:

[0099] Under the nitrogen atmosphere, 2-bromo-3-(2-acetyloxyethyl)thiophene (0.025 mmol), 2-bromo-3-hexylthiophene (0.475 mmol), potassium carbonate (0.75 mmol), ester-substituted palladium complex C3 (0.25 mmol%), pivalic acid (0.15 mmol), dimethylacetamide (4 mL) were reacted at 100°C for 24 h, and the ester-thiophene-hexylthiophene copolymer L7 was obtained by precipitation in methanol, with a yield of 73%, HT value of 87%, PDI of 3.5, number average molecular weight Mn of 13.6 KDa, and 3-(2-acetyloxyethyl)thiophene segment accounting for 4.7% of the molar percentage of the ester-thiophene-hexylthiophene copolymer segment, i.e., the copolymerization degree is 4.7 mmol%; the structures of the ester-substituted palladium complex C3 and the ester-thiophene-hexylthiophene copolymer L7 are shown as follows:

[0100]

[0101] wherein x = 4.7 mmol%, y = 95.3 mmol%.

[0102] As can be seen from Examples 4-10, the ester-thiophene-hexylthiophene copolymer of the present application has a random structure, high regularity, and high molecular weight.

[0103] 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. An ester-substituted palladium complex, characterized in that, The structural formula of the ester-substituted palladium complex is shown as formula (I): Formula (I) wherein R1, R2, R3 are independently selected from hydrogen or methyl formate group, and R1, R2, R3 are not hydrogen at the same time.

2. The ester-substituted palladium complex of claim 1, wherein, The structural formula of the ester-substituted palladium complex is shown as formula (I): Formula (I) wherein R1, R3 are selected from hydrogen, and R2 is selected from methyl formate group.

3. The ester-substituted palladium complex of claim 1, wherein, The structural formula of the ester-substituted palladium complex is shown as formula (I): Formula (I) wherein R1, R2 are selected from methyl formate group, and R3 is selected from hydrogen.

4. A process for the preparation of the ester-substituted 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 ester-substituted palladium complex.

5. The process for the preparation of ester-substituted palladium complexes according to claim 4, characterized in that, The molar ratio of the ligand to PdCl2 is 1:0.51-0.

55.

6. The method of claim 4, wherein the ester-substituted palladium complex is prepared by the reaction of a palladium compound with an ester compound in the presence of a base. The reaction temperature is 60-100℃, and the reaction time is 20-50min.

7. Use of the ester-substituted palladium complex prepared by the method of any one of claims 1-3 or any one of claims 4-6 in the preparation of an ester-substituted thiophene-hexylthiophene copolymer.

8. Use according to claim 7, characterized in that, The structural formula of the ester-substituted thiophene-hexylthiophene copolymer is shown as formula (II) or formula (III): Formula (II) Formula (III) wherein the molar percentage of the ester-substituted thiophene segment in the ester-substituted thiophene-hexylthiophene copolymer segment is 2.6%-13.9%, and the number average molecular weight of the ester-substituted thiophene-hexylthiophene copolymer is 9.3-17.3KDa.

9. Use according to claim 7, characterized in that, The HT value of the ester-substituted thiophene-hexylthiophene copolymer is ≥80%.

10. Use according to claim 7, characterized in that, The ester-substituted thiophene-hexylthiophene copolymer is a random copolymer.

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