Quinone dithiophene aza-isoindigo polymer as well as preparation method and application thereof

Abstract

The invention discloses a quinone-type bithiophene aza-isoindigo polymer and a preparation method and application thereof, and belongs to the technical field of organic semiconductor materials, the structural formula of the quinone-type bithiophene aza-isoindigo polymer is as shown in formula I. In the polymer, R is one of C5-C80 straight-chain or branched-chain alkyl, and X is fluorine or hydrogen; and the polymerization degree n is 5-200. The polymer is prepared through nucleophilic addition, reduction, dehydrogenation and Stille copolymerization in sequence. The synthetic route is simple and easy to implement, few in synthetic steps, high in synthetic yield and suitable for large-scale synthesis; a field effect transistor prepared by taking the polymer as an organic semiconductor layer has excellent bipolar transmission characteristics, the highest electron mobility is 1.44 cm < 2 > V <-1 > s <-1 >, the highest hole mobility is 0.77 cm < 2 > V <-1 > s <-1 >, and the polymer has wide application prospects in organic field effect transistors.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic semiconductor materials, and in particular relates to a quinone-type bithiophene azaisoindigo polymer and a preparation method and application thereof. Background Art

[0002] Semiconductors, with electrical properties intermediate between those of conductors and insulators, are core materials for modern electronic devices and are widely used in a wide range of fields, including medical, display, storage, communications, and energy. With technological innovation and economic growth, the application areas and market size of semiconductors are expanding. Modern society has entered an intelligent information age, thanks to the continuous advancement of semiconductor technology, which has not only changed people's lifestyles but also promoted the development and progress of human society. In current commercial applications, most semiconductors are based on inorganic materials such as selenium, germanium, and silicon. However, due to the inherent rigidity limitations of these materials, they cannot meet the application requirements of specific devices, especially flexible electronic devices. With the continuous expansion of the flexible device market and the growing demand for wearable electronic products, the development of new semiconductor materials has attracted widespread attention from academia and industry.

[0003] Thanks to the diligent exploration of researchers, the global semiconductor industry is undergoing a profound transformation, transitioning from traditional inorganic materials to a new generation of organic materials. Compared to inorganic semiconductors, organic semiconductors offer advantages such as lightweight, low cost, excellent solution processability, inherent flexibility, and biocompatibility. Furthermore, the diverse range of organic materials allows for the synthesis of thousands of small molecule and polymer semiconductor materials through molecular design, and molecular modification can be used to tune optoelectronic properties and device performance. Compared to small molecule semiconductors, polymer semiconductors offer better film-forming properties and ductility, leading to their widespread application in organic electronics.

[0004] Organic field-effect transistors (OFETs) are active devices that use organic semiconductor materials as active layers and regulate channel current through gate voltage. OFETs are mainly composed of gate, source and drain electrodes, insulating layer and organic semiconductor layer. The performance parameters of OFETs include carrier mobility (μ), on-off ratio (I on / I off ) and threshold voltage (V TH ). Where μ and I on / I off The higher the value, the higher the V THThe closer it is to 0, the better the performance of the OFETs. After the first polymer-based OFETs were reported in 1986, OFETs quickly became a hot topic of scientific research. In recent years, with the rapid development of polymer semiconductor materials, the device performance of OFETs has also been continuously improved. At present, p-type polymer semiconductor materials have made brilliant achievements, and the mobility is constantly being refreshed. However, the mobility and device stability of n-type and ambipolar polymer semiconductor materials lag far behind p-type materials and cannot meet the needs of practical applications. Therefore, the development of new n-type and ambipolar polymer materials is of great value. Summary of the Invention

[0005] In view of this, the present invention discloses a quinone-type bithiophene azaisoindigo polymer and a preparation method and application thereof.

[0006] The present invention adopts the following technical solutions:

[0007] A quinone-type bithiophene azaisoindigo polymer, the structural formula of which is shown in Formula I:

[0008]

[0009] In the formula I, R is C5-C 80 One of the straight or branched alkyl groups; wherein X in the formula I is selected from fluorine or hydrogen;

[0010] In the formula I, n is the number of repetitions of the polymer main chain unit, n is a natural number, and 5≤n≤200.

[0011] Furthermore, in the formula I, R is C 10 -C 50 One of the straight-chain or branched-chain alkyl groups; 10≤n≤100.

[0012] Furthermore, in the formula I, R is C 10 -C 30 One of the straight-chain or branched-chain alkyl groups; 40≤n≤67.

[0013] Furthermore, in the formula I, R is one of 2-decyltetradecyl or 4-decyltetradecyl; and n is 40, 46, 63 or 67.

[0014] A method for preparing the above polymer, such as Figure 1 As shown, the preparation method comprises the following steps:

[0015] S1. In an inert atmosphere, the compound represented by Formula II is reacted with a lithium reagent and N,N,N',N'-tetramethylethylenediamine to form the corresponding lithium salt, which is then rapidly reacted with the compound represented by Formula III for a nucleophilic addition reaction to obtain the synthetic intermediate represented by Formula IV. Formulas II, III, and IV are as follows:

[0016]

[0017] , X in the formula II is the same as X in the polymer represented by formula I, and R in the formula III is the same as R in the polymer represented by formula I;

[0018] S2. In the presence of a reducing agent, the compound represented by formula IV is subjected to a reduction reaction to obtain an intermediate represented by formula V; the formula V is as follows:

[0019]

[0020] S3. In the presence of an oxidizing agent, the compound represented by formula V is subjected to a dehydrogenation reaction, and the reaction is completed to obtain a monomer represented by formula VI; the formula VI is as follows:

[0021]

[0022] S4. In an inert atmosphere, in the presence of a palladium catalyst and a phosphine ligand, the compound represented by Formula VI and the compound represented by Formula VII are subjected to a Stille copolymerization reaction to obtain a polymer represented by Formula I, wherein the formula VII is shown below:

[0023]

[0024] Furthermore, in step S1:

[0025] The lithium reagent is a 1.6M hexane solution of n-butyl lithium or a 2.5M hexane solution of n-butyl lithium;

[0026] The molar ratio of the compound represented by formula II to the compound represented by formula III is 1:2.2-2.5;

[0027] The lithium reagent and N,N,N',N'-tetramethylethylenediamine are used in the same amount, and the molar ratio of the two is 1:1; the molar ratio of the lithium reagent to the compound represented by formula II is 2.2-2.5:1;

[0028] The generation of the corresponding lithium salt and the nucleophilic addition reaction in step S1 are carried out in anhydrous tetrahydrofuran solvent; the reaction temperature for generating the corresponding lithium salt is -35°C, and the reaction time is 0.5 to 2 hours; the nucleophilic addition reaction is started by stirring at -35°C for 30 minutes, then heated to 18-22°C, and the reaction time is 6 to 24 hours; the inert atmosphere in step S1 includes a nitrogen atmosphere or an argon atmosphere.

[0029] Furthermore, in step S2:

[0030] The reducing agent is anhydrous stannous chloride or stannous chloride dihydrate;

[0031] The molar ratio of the compound represented by formula V to the reducing agent is 1:5-10;

[0032] The reaction temperature of the reduction reaction is 80-120° C., and the reaction time is 1-5 hours;

[0033] The reduction reaction is carried out in a mixed solvent of glacial acetic acid and tetrahydrofuran, wherein the volume ratio of the glacial acetic acid to the tetrahydrofuran in the mixed solvent is 1:1-2.

[0034] Furthermore, in step S3:

[0035] The oxidant is 2,3-dichloro-5,6-dicyanobenzoquinone;

[0036] The molar ratio of the compound represented by formula V to the oxidant is 1:3-5;

[0037] The reaction temperature of the dehydrogenation reaction is 18-22°C, and the reaction time is 0.5-5h;

[0038] The dehydrogenation reaction is carried out in toluene solvent.

[0039] Furthermore, in step S4:

[0040] The palladium catalyst includes tetrakis(triphenylphosphine)palladium or tris(dibenzylideneacetone)dipalladium; the phosphine ligand includes tri(o-tolyl)phosphine or triphenylphosphine;

[0041] In the Stille copolymerization reaction, the molar ratio of the compound represented by formula VI, the compound represented by formula VII, the palladium catalyst and the phosphine ligand is 1:0.95-1.05:0.01-0.10:0.10-0.50, the reaction temperature is 90-120° C., and the reaction time is 24-72 hours.

[0042] The Stille copolymerization reaction is carried out in a nitrogen atmosphere or an argon atmosphere;

[0043] The reaction is carried out in toluene or chlorobenzene solvent.

[0044] An application of the above polymer is application of the polymer in preparing an organic field effect transistor, wherein the organic semiconductor layer of the organic field effect transistor is made of the polymer.

[0045] Beneficial effects of the present invention:

[0046] 1. The raw materials for the synthesis of the quinone-type bithiophene azaisoindigo polymer of the present invention can be simply synthesized or purchased in large quantities through commercial channels. The method of the present invention is suitable for large-scale synthesis;

[0047] 2. The quinone-type bithiophene azaisoindigo polymer of the present invention has good thermal stability, broad UV-visible light absorption properties, a narrow optical band gap, and good solution processability, and is expected to be used to prepare high-performance OFETs by solution processing;

[0048] 3. The OFETs prepared with the quinone-type bithiophene nitrogen isoindigo polymer as the semiconductor layer have excellent electron / hole mobility (μ e / μ h )(The optimal value is μ e / μ h 1.44 / 0.77cm 2 V –1 s –1 ), which has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0050] Figure 1 : Schematic diagram of the synthesis route of the quinone-type bithiophene azaisoindigo polymer represented by formula I of the present invention;

[0051] Figure 2 : Schematic diagram of the synthesis routes of polymers P1, P1-2F, P2 and P2-2F in Examples 2, 3, 4 and 5 of the present invention;

[0052] Figure 3 : Schematic diagrams of the structures of polymers P1, P1-2F, P2 and P2-2F in Examples 2, 3, 4 and 5 of the present invention;

[0053] Figure 4 : Schematic diagram of the UV-visible absorption spectra of dichlorobenzene solutions of polymers P1, P1-2F, P2 and P2-2F in Examples 2, 3, 4 and 5 of the present invention;

[0054] Figure 5 : Schematic diagram of the UV-visible absorption spectra of the polymer P1, P1-2F, P2 and P2-2F films described in Examples 2, 3, 4 and 5 of the present invention;

[0055] Figure 6 : Schematic diagram of thermogravimetric analysis curves of polymers P1, P1-2F, P2 and P2-2F described in Examples 2, 3, 4 and 5 of the present invention;

[0056] Figure 7 : Schematic diagram of output transfer characteristic curves and output characteristic curves of representative polymer P1-based OFETs of the present invention;

[0057] Figure 8 : Schematic diagram of output transfer characteristic curves and output characteristic curves of representative polymer P1-2F-based OFETs of the present invention;

[0058] Figure 9 : Schematic diagram of output transfer characteristic curves and output characteristic curves of representative polymer-based P2 OFETs of the present invention;

[0059] Figure 10 : Schematic diagram of the output transfer characteristic curve and the output characteristic curve of the representative polymer P2-2F-based OFETs of the present invention. DETAILED DESCRIPTION

[0060] In order to better understand the technical solution of the present invention, the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0061] It should be understood that the embodiments described are only a portion of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0062] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0063] Unless otherwise specified, the materials and reagents used in the following examples can be purchased from commercial sources.

[0064] The reaction substrates compound 2a and compound 2b used in the following examples were synthesized with reference to the literature Polymer, 2021, 215, 123347 and CCS Chem., 2024, 6, 473–486, respectively. The remaining reaction substrates, solvents, catalysts and ligands used were all commercially available.

[0065] Example 1

[0066] A quinone-type bithiophene azaisoindigo polymer, the structural formula of which is shown in Formula I:

[0067]

[0068] In the formula I, R is C5-C 80 One of the straight or branched alkyl groups; wherein X in the formula I is selected from fluorine or hydrogen;

[0069] In the formula I, n is the number of repetitions of the polymer main chain unit, n is a natural number, and 5≤n≤200.

[0070] Furthermore, in the formula I, R is C 10 -C 50 One of the straight-chain or branched-chain alkyl groups; 10≤n≤100.

[0071] Furthermore, in the formula I, R is C 10 -C 30 One of the straight-chain or branched-chain alkyl groups; 40≤n≤67.

[0072] Furthermore, in the formula I, R is one of 2-decyltetradecyl or 4-decyltetradecyl; and n is 40, 46, 63 or 67.

[0073] A method for preparing the above polymer, comprising the following steps:

[0074] S1. In an inert atmosphere, the compound represented by Formula II is reacted with a lithium reagent and N,N,N',N'-tetramethylethylenediamine to form the corresponding lithium salt, which is then rapidly reacted with the compound represented by Formula III for a nucleophilic addition reaction to obtain the synthetic intermediate represented by Formula IV. Formulas II, III, and IV are as follows:

[0075]

[0076] , X in the formula II is the same as X in the polymer represented by the final product of the preparation method, formula I, and R in the formula III is the same as R in the polymer represented by the final product, formula I;

[0077] S2. In the presence of a reducing agent, the compound represented by formula IV is subjected to a reduction reaction to obtain an intermediate represented by formula V; the formula V is as follows:

[0078]

[0079] S3. In the presence of an oxidizing agent, the compound represented by formula V is subjected to a dehydrogenation reaction, and the reaction is completed to obtain a monomer represented by formula VI; the formula VI is as follows:

[0080]

[0081] S4. In an inert atmosphere, in the presence of a palladium catalyst and a phosphine ligand, the compound represented by Formula VI and the compound represented by Formula VII are subjected to a Stille copolymerization reaction to obtain a polymer represented by Formula I, wherein the formula VII is shown below:

[0082]

[0083] Furthermore, in step S1:

[0084] The lithium reagent is a 1.6M hexane solution of n-butyl lithium or a 2.5M hexane solution of n-butyl lithium;

[0085] The molar ratio of the compound represented by formula II to the compound represented by formula III is 1:2.2-2.5;

[0086] The lithium reagent and N,N,N',N'-tetramethylethylenediamine are used in the same amount, and the molar ratio of the two is 1:1; the molar ratio of the lithium reagent to the compound represented by formula II is 2.2-2.5:1;

[0087] The generation of the corresponding lithium salt and the nucleophilic addition reaction in step S1 are carried out in anhydrous tetrahydrofuran solvent; the reaction temperature for generating the corresponding lithium salt is -35°C, and the reaction time is 0.5 to 2 hours; the nucleophilic addition reaction is started by stirring at -35°C for 30 minutes, then heated to 18-22°C, and the reaction time is 6 to 24 hours; the inert atmosphere in step S1 includes a nitrogen atmosphere or an argon atmosphere.

[0088] In step S1, within the above-mentioned feeding molar ratio range, the above-mentioned reaction time range, and the reaction temperature range, step 1 can achieve the reaction effect of the method of the present invention.

[0089] Furthermore, in step S2:

[0090] The reducing agent is anhydrous stannous chloride or stannous chloride dihydrate;

[0091] The molar ratio of the compound represented by formula V to the reducing agent is 1:5-10;

[0092] The reaction temperature of the reduction reaction is 80-120° C., and the reaction time is 1-5 hours;

[0093] The reduction reaction is carried out in a mixed solvent of glacial acetic acid and tetrahydrofuran, wherein the volume ratio of the glacial acetic acid to the tetrahydrofuran in the mixed solvent is 1:1-2.

[0094] In step S2, within the above-mentioned feeding molar ratio range, the above-mentioned reaction time range, and the reaction temperature range, step S2 can achieve the reaction effect of the method of the present invention.

[0095] Furthermore, in step S3:

[0096] The oxidant is 2,3-dichloro-5,6-dicyanobenzoquinone;

[0097] The molar ratio of the compound represented by formula V to the oxidant is 1:3-5;

[0098] The reaction temperature of the dehydrogenation reaction is 18-22°C, and the reaction time is 0.5-5h;

[0099] The dehydrogenation reaction is carried out in toluene solvent.

[0100] In step S3, within the above-mentioned feeding molar ratio range, the above-mentioned reaction time range, and the reaction temperature range, step S3 can achieve the reaction effect of the method of the present invention.

[0101] Furthermore, in step S4:

[0102] The palladium catalyst includes tetrakis(triphenylphosphine)palladium or tris(dibenzylideneacetone)dipalladium; the phosphine ligand includes tri(o-tolyl)phosphine or triphenylphosphine;

[0103] In the Stille copolymerization reaction, the molar ratio of the compound represented by formula VI, the compound represented by formula VII, the palladium catalyst and the phosphine ligand is 1:0.95-1.05:0.01-0.10:0.10-0.50, the reaction temperature is 90-120° C., and the reaction time is 24-72 hours.

[0104] The Stille copolymerization reaction is carried out in a nitrogen atmosphere or an argon atmosphere;

[0105] The reaction is carried out in toluene or chlorobenzene solvent.

[0106] In step S4, within the above-mentioned feeding molar ratio range, the above-mentioned reaction time range, and the reaction temperature range, step S4 can achieve the reaction preparation effect of the method of the present invention.

[0107] An application of the above polymer is application of the polymer in preparing an organic field effect transistor, wherein the organic semiconductor layer of the organic field effect transistor is made of the polymer.

[0108] Example 2

[0109] The polymer P1 is synthesized. The polymer P1 corresponds to formula I, wherein R is 2-decyltetradecyl, X=H, and the structural formula of P1 is as follows: Figure 3 Its synthetic route is shown in Figure 2 shown.

[0110] 1) Synthesis of compound 3a represented by formula IV.

[0111] 2,2'-bithiophene (structural formula: Figure 2 Compound 1a (shown in FIG, 0.33 g, 2 mmol), TMEAD (0.51 g, 4.4 mmol) and 20 mL of anhydrous THF were added, and then n-BuLi (2.5 M in Hexane, 1.8 mL, 4.4 mmol) was added dropwise at -35°C. The solution was deoxygenated under argon and stirred at -35°C for 1 h. The mixture was then directly transferred to compound (structural formula: Figure 2 The mixture was stirred at -35 ° C for 30 minutes, then heated to room temperature and stirred overnight. The room temperature mentioned in this example and the following examples was 18-22 ° C. Then, it was quenched with NH4Cl solution, extracted with ethyl acetate and water, and then dried over anhydrous THF (50 mL). Na2SO4 After drying, the solvent was removed under reduced pressure and purified by silica gel chromatography (ethyl acetate / petroleum ether = 1:4) to afford 1.68 g of a black viscous liquid (Compound 3a of Formula IV). Yield: 65%. Compound 3a was unstable and was immediately carried to the next step.

[0112] 2) Synthesis of compound 4a represented by formula V.

[0113] Compound 3a (1.25 g, 1.0 mmol) was added to THF (7.5 mL) and CH3COOH (7.5 mL), and a solution of SnCl2 (1.06 g, 5.6 mmol) in 0.75 mL of saturated HCl was added. The mixture was stirred at 100°C for 1 h. After cooling to room temperature, the mixture was extracted with ethyl acetate and water, and then dried over anhydrous Na2SO4. The solvent was removed under reduced pressure to obtain 1.14 g of a bluish-black solid (i.e., compound 4a of Formula V), which was used directly in the next step without purification. Yield: 90%.

[0114] 3) Synthesis of compound 5a represented by formula VI.

[0115] A solution of compound 4a (1.0 g, 0.8 mmol) was added to toluene (20 mL), followed by DDQ (0.55 g, 2.40 mmol) at room temperature. The mixture was stirred at room temperature for 1 h. After removing the toluene under reduced pressure, the mixture was purified by silica gel chromatography (dichloromethane / petroleum ether = 1:1) to afford 0.82 g of the monomer (i.e., compound 5a of Formula VI) as a bluish-black solid. Yield: 82%.

[0116] The structural characterization data of compound 5a represented by formula VI are as follows:

[0117] Mass spectrum: HRMS (m / z): [M+H] + :1259.61.

[0118] Proton spectrum: 1 H NMR(400MHz, CDCl2CDCl2)δ8.56(d,J=5.7Hz,1H),7.75–7.50(m,5H),7.27–7.14(m ,2H),3.84–3.68(m,4H),2.06(s,2H),1.70–1.26(m,80H),0.90(t,J=6.6Hz,12H).

[0119] Carbon spectrum: 13 C NMR (101 MHz, CDCl2CDCl2)δ

[0120] 167.07,165.39,155.69,154.91,151.25,150.03,149.86,142.72,142.59,141.33,139.62,138.82,134.09,120.82,115.48,114.69,114.58,113.37,43.44,36.33,36.24,31.99,31.48,30.06,29.79,29.77,29.74,29.71,29.66,29.43,29.41,26.24,22.79,14.31.

[0121] 4) Synthesis of polymer P1.

[0122] Compound 5a (125.96 mg, 0.10 mmol) of Formula VI, 2,5-bis(trimethyltinyl)thiophene (40.98 mg, 0.10 mmol) of Formula VII, palladium catalyst Pd2(dba)3 (3.0 mg, 0.00328 mmol), ligand P(o-tol)3 (9.0 mg, 0.0296 mmol), and degassed chlorobenzene (5.0 mL) were added to a reaction flask. The mixture was deoxygenated under argon at low temperature and then heated to 120°C for polymerization for 24 hours. After cooling, 200 mL of a methanol / 6M HCl mixture (volume ratio 20:1) was added, stirred at room temperature for 2 hours, and filtered. The resulting solid was purified by Soxhlet extraction using methanol, acetone, and n-hexane, sequentially for 12 hours each. The resulting solid was then extracted with chlorobenzene to yield 108.9 mg of the target polymer (polymer P1, shown in the figure), in a 92% yield.

[0123] The structural characterization data are as follows:

[0124] Molecular weight: GPC:M n =53.6kDa, PDI=2.30, n=46;

[0125] Elemental analysis: C74 H 110 N4O2S3, calculated values: C75.08, H9.37, N4.73, S8.12; found values: C75.03, H9.11, N4.64, S8.24;

[0126] From the above, we know that the structure of the compound is correct and it is polymer P1.

[0127] Example 3

[0128] The polymer P1-2F is synthesized. The polymer P1-2F corresponds to formula I, wherein R is 2-decyltetradecyl and X=F. The structural formula of P1-2F is as follows: Figure 3 The synthetic route is shown in Figure 2 shown.

[0129] 1) Synthesis of compound 3b represented by formula IV.

[0130] 3,3'-difluoro-2,2'-bithiophene (structural formula: Figure 2 Compound 1b (0.404 g, 2 mmol), TMEAD (0.51 g, 4.4 mmol) and 20 mL of anhydrous THF were added, and then n-BuLi (2.5 Min Hexane, 1.8 mL, 4.4 mmol) was added dropwise at -35°C. The solution was deoxygenated under argon and stirred at -35°C for 1 h. The mixture was then directly transferred to compound (structural formula: Figure 2 The product (2.48 g, 4.4 mmol) was added to a solution of compound 2a (shown in Formula IV) in anhydrous THF (50 mL). The mixture was stirred at -35°C for 30 minutes, then warmed to room temperature and stirred overnight. The mixture was then quenched with NH4Cl solution, extracted with ethyl acetate and water, and dried over anhydrous Na2SO4. The solvent was removed under reduced pressure and purified by silica gel chromatography (ethyl acetate / petroleum ether = 1:4) to afford 1.64 g of a black viscous liquid (i.e., compound 3b of Formula IV). Yield: 62%. Compound 3b was unstable and was immediately carried to the next step.

[0131] 2) Synthesis of compound 4b represented by formula V.

[0132] Compound 3a (1.33 g, 1.0 mmol) was added to THF (7.5 mL) and CH3COOH (7.5 mL), and a solution of SnCl2 (1.06 g, 5.6 mmol) in 0.75 mL of saturated HCl was added. The mixture was stirred at 100°C for 1 h. After cooling to room temperature, the mixture was extracted with ethyl acetate and water, and then dried over anhydrous Na2SO4. The solvent was removed under reduced pressure to obtain 1.20 g of a bluish-black solid (i.e., compound 4b of Formula V), which was used in the next step without purification. Yield: 92%.

[0133] 3) Synthesis of compound 5b represented by formula VI.

[0134] A solution of compound 4b (1.04 g, 0.80 mmol) was added to toluene (20 mL), followed by DDQ (0.55 g, 2.40 mmol) at room temperature. The mixture was stirred at room temperature for 1 h. After removing the toluene under reduced pressure, the mixture was purified by silica gel chromatography (dichloromethane / petroleum ether = 1:1) to afford 0.81 g of the monomer (i.e., compound 5b of Formula VI) as a bluish-black solid. Yield: 78%.

[0135] The structural characterization data of compound 5b represented by formula VI are as follows:

[0136] Mass spectrum: HRMS (m / z): [M+H] + :1295.59.

[0137] Proton spectrum: 1 H NMR (400 MHz, CDCl2CDCl2)δ

[0138] 8.37(t,J=2.0Hz,1H),7.53(dd,J=8.2,2.3Hz,1H),7.47(dd,J=7.9,3.6Hz,1H),7.32(s,1H),7.21– 7.14(m,2H),3.72(dd,J=20.6,7.0Hz,4H),2.03(s,2H),1.71–1.16(m,80H),0.90(t,J=6.7Hz,12H).

[0139] Carbon spectrum: 13 C NMR (101 MHz, CDCl2CDCl2)δ

[0140] 166.61,166.51,165.11,164.71,163.75,163.38,162.32,161.92,155.56,155.47,155.12,144.54,144.44,143.86,143.77,140.13,140.05,139.53,130.91,129.05,127.27,127.12,127.01,1 20.93,115.16,114.84,114.71,114.25,114.18,113.54,113.44,43.72,43.38,36.29,36.19,32.00,31.48,30.05,29.81,29.78,29.76,29.72,29.67,29.45,29.42,26.25,26.23,22.79,14.30.

[0141] 4) Synthesis of polymer P1-2F.

[0142] Compound 5b (129.55 mg, 0.10 mmol) of Formula VI, 2,5-bis(trimethyltinyl)thiophene (40.98 mg, 0.10 mmol) of Formula VII, palladium catalyst Pd2(dba)3 (3.0 mg, 0.00328 mmol), ligand P(o-tol)3 (9.0 mg, 0.0296 mmol), and degassed chlorobenzene (5.0 mL) were added to a reaction flask. The mixture was deoxygenated at low temperature under argon and then heated to 120°C for polymerization for 24 hours. After cooling, 200 mL of a methanol / 6M HCl mixture (volume ratio 20:1) was added, stirred at room temperature for 2 hours, and filtered. The resulting solid was purified by Soxhlet extraction with methanol, acetone, and n-hexane for 12 hours each. The resulting solid was then extracted with chlorobenzene to yield 109.8 mg of the target polymer (polymer P1-2F, shown in the figure), in a 90% yield.

[0143] The structural characterization data are as follows:

[0144] Molecular weight: GPC:M n =76.8kDa, PDI=2.10, n=63;

[0145] Elemental analysis: C 74 H 108 F2N4O2S3, calculated values: C72.86, H8.92, N4.59, S7.88; found values: C72.60, H8.64, N4.52, S7.95;

[0146] From the above, we know that the structure of the compound is correct, and it is polymer P1-2F.

[0147] Example 4

[0148] The polymer P2 is synthesized. The polymer P2 corresponds to formula I, wherein R is 4-decyltetradecyl, X=H, and the structural formula of P2 is as follows: Figure 3 Its synthetic route is shown in Figure 2 shown.

[0149] 1) Synthesis of compound 3c represented by formula IV.

[0150] 2,2'-bithiophene ((structural formula as Figure 2Compound 1a (shown in FIG, 0.33 g, 2 mmol), TMEAD (0.51 g, 4.4 mmol) and 20 mL of anhydrous THF were added, and then n-BuLi (2.5 M in Hexane, 1.8 mL, 4.4 mmol) was added dropwise at -35°C. The solution was deoxygenated under argon and stirred at -35°C for 1 h. The mixture was then directly transferred to compound (structural formula: Figure 2 The product (2.48 g, 4.4 mmol, compound 2b) was added to a solution of anhydrous THF (50 mL). The mixture was stirred at -35°C for 30 minutes, then warmed to room temperature and stirred overnight. The mixture was then quenched with NH4Cl solution, extracted with ethyl acetate and water, and dried over anhydrous Na2SO4. The solvent was removed under reduced pressure and purified by silica gel chromatography (ethyl acetate / petroleum ether = 1:4) to afford 1.75 g of a black viscous liquid (i.e., compound 3c of Formula IV). Yield: 68%. Compound 3c was unstable and was immediately carried to the next step.

[0151] 2) Synthesis of compound 4c represented by formula V.

[0152] Compound 3c (1.25 g, 1.0 mmol) was added to THF (7.5 mL) and CH3COOH (7.5 mL), followed by the addition of a solution of SnCl2 (1.06 g, 5.6 mmol) in 0.75 mL of saturated HCl. The mixture was stirred at 100°C for 1 h. After cooling to room temperature, the mixture was extracted with ethyl acetate and water, and then dried over anhydrous Na2SO4. The solvent was removed under reduced pressure to yield 1.13 g of a bluish-black solid (i.e., compound 4c of Formula V), which was used directly in the next step without purification. Yield: 90%.

[0153] 3) Synthesis of compound 5c represented by formula VI.

[0154] A solution of compound 4c (1.0 g, 0.80 mmol) was added to toluene (20 mL), followed by DDQ (0.55 g, 2.40 mmol) at room temperature. The mixture was stirred at room temperature for 1 h. After removing the toluene under reduced pressure, the mixture was purified by silica gel chromatography (dichloromethane / petroleum ether = 1:1) to afford 0.84 g of the monomer (i.e., compound 5c of Formula VI) as a bluish-black solid. Yield: 83%.

[0155] The structural characterization data of compound 5c represented by formula VI are as follows:

[0156] Mass spectrum: HRMS (m / z): [M+H] + :1259.61.

[0157] Proton spectrum: 1H NMR(400MHz, CDCl2CDCl2)δ8.57(dd,J=11.9,5.7Hz,1H),7.77–7.48(m,5H),7.23–7.16 (m,2H),3.96–3.77(m,4H),1.65(s,10H),1.26(d,J=10.7Hz,72H),0.93–0.87(m,12H).

[0158] Carbon spectrum: 13 C NMR (101 MHz, CDCl2CDCl2)δ

[0159] 166.81,165.11,155.34,154.52,152.12,150.41,141.56,141.36,139.53,139.01,138.86,136.86,136.14,135.22,132.90,132.62,132.51,131.08,130.80,129.04,124.51,123.55,122.29,121.76,1 20.86,117.26,115.67,115.14,114.29,113.37,113.30,111.52,110.04,39.68,37.48,37.06,33.57,32.78,32.00,30.69,30.39,30.22,29.80,29.76,29.44,27.17,26.71,24.96,22.79,19.86,14.31.

[0160] 4) Synthesis of polymer P2.

[0161] Compound 5c (125.96 mg, 0.10 mmol) of Formula VI, 2,5-bis(trimethyltinyl)thiophene (40.98 mg, 0.10 mmol) of Formula VII, palladium catalyst Pd2(dba)3 (3.0 mg, 0.00328 mmol), ligand P(o-tol)3 (9.0 mg, 0.0296 mmol), and degassed chlorobenzene (5.0 mL) were added to a reaction flask. The mixture was deoxygenated at low temperature under argon and then heated to 120°C for polymerization for 24 hours. After cooling, 200 mL of a methanol / 6M HCl mixture (volume ratio 20:1) was added, stirred at room temperature for 2 hours, and filtered. The resulting solid was purified by Soxhlet extraction using methanol, acetone, and n-hexane, sequentially for 12 hours each. The resulting solid was then extracted with chlorobenzene to yield 110.1 mg of the target polymer (polymer P2, shown in the figure), in a 93% yield.

[0162] The structural characterization data are as follows:

[0163] Molecular weight: GPC:M n =46.9 kDa, PDI = 2.26, n is 40;

[0164] Elemental analysis: C 74 H 110 N4O2S3, calculated values: C75.08, H9.37, N4.73, S8.12; found values: 75.03, H9.21, N4.52, S7.96;

[0165] From the above, we know that the structure of the compound is correct and it is polymer P2.

[0166] Example 5

[0167] The polymer P2-2F is synthesized. The polymer P2-2F corresponds to formula I, wherein R is 4-decyltetradecyl and X=F. The structural formula of P2-2F is as follows: Figure 3 Its synthetic route is shown in Figure 2 shown.

[0168] 1) Synthesis of compound 3d represented by formula IV.

[0169] 3,3'-difluoro-2,2'-bithiophene (structural formula: Figure 2 Compound 1b (0.404 g, 2 mmol), TMEAD (0.51 g, 4.4 mmol) and 20 mL of anhydrous THF were added, and then n-BuLi (2.5 Min Hexane, 1.8 mL, 4.4 mmol) was added dropwise at -35°C. The solution was deoxygenated under argon and stirred at -35°C for 1 h. The mixture was then directly transferred to compound (structural formula: Figure 2 The product (2.48 g, 4.4 mmol, compound 2b) was added to a solution of anhydrous THF (50 mL). The mixture was stirred at -35°C for 30 minutes, then warmed to room temperature and stirred overnight. The mixture was then quenched with NH4Cl solution, extracted with ethyl acetate and water, and dried over anhydrous Na2SO4. The solvent was removed under reduced pressure and purified by silica gel chromatography (ethyl acetate / petroleum ether = 1:4) to afford 1.74 g of a black viscous liquid (i.e., compound 3d of formula IV). Yield: 66%. Compound 3d was unstable and was immediately carried to the next step.

[0170] 2) Synthesis of compound 4d represented by formula V.

[0171] Compound 3d (1.33 g, 1.0 mmol) was added to THF (7.5 mL) and CH3COOH (7.5 mL), followed by a solution of SnCl2 (1.06 g, 5.6 mmol) in 0.75 mL of saturated HCl. The mixture was stirred at 100°C for 1 h. After cooling to room temperature, the mixture was extracted with ethyl acetate and water, and then dried over anhydrous Na2SO4. The solvent was removed under reduced pressure to yield 1.16 g of a bluish-black solid (i.e., compound 4d of Formula V), which was used in the next step without purification. Yield: 90%.

[0172] 3) Synthesis of compound 5d represented by formula VI.

[0173] A solution of compound 4d (1.04 g, 0.80 mmol) was added to toluene (20 mL), followed by DDQ (0.55 g, 2.40 mmol) at room temperature. The mixture was stirred at room temperature for 1 h. After removing the toluene under reduced pressure, the mixture was purified by silica gel chromatography (dichloromethane / petroleum ether = 1:1) to afford 0.83 g of the monomer (i.e., compound 5d of Formula VI) as a bluish-black solid. Yield: 80%.

[0174] The structural characterization data of compound 5d represented by formula VI are as follows:

[0175] Mass spectrum: HRMS (m / z): [M+H] + :1295.56.

[0176] Proton spectrum: 1 H NMR(400MHz, CDCl2CDCl2)δ8.39(d,J=2.3Hz,1H),7.61–7.46(m,2H),7.32(d,J=8.9Hz,1H),7.26 –7.15(m,2H),3.93–3.73(m,4H),1.65(s,10H),1.26(d,J=13.0Hz,72H),0.90(t,J=6.7Hz,12H).

[0177] Carbon spectrum: 13 C NMR (101 MHz, CDCl2CDCl2)δ

[0178] 173.47,170.85,166.37,164.89,156.07,154.77,151.25,147.06,140.56,140.14,134.08,133.97,130.60,130.51,126.52,126.41,125.38,125.15,121. 00,120.13,115.42,114.91,113.31,112.49,112.06,109.98,39.67,37.00,33.55,32.00,30.65,30.22,29.81,29.76,29.45,26.71,24.85,22.79,14.31.

[0179] 4) Synthesis of polymer P2-2F.

[0180] Compound 5d (129.55 mg, 0.10 mmol) of Formula VI, 2,5-bis(trimethyltinyl)thiophene (40.98 mg, 0.10 mmol) of Formula VII, palladium catalyst Pd2(dba)3 (3.0 mg, 0.00328 mmol), ligand P(o-tol)3 (9.0 mg, 0.0296 mmol), and degassed chlorobenzene (5.0 mL) were added to a reaction flask. The mixture was deoxygenated under argon at low temperature and then heated to 120°C for polymerization for 24 hours. After cooling, 200 mL of a methanol / 6M HCl mixture (volume ratio 20:1) was added, stirred at room temperature for 2 hours, and filtered. The resulting solid was purified by Soxhlet extraction with methanol, acetone, and n-hexane for 12 hours each. The resulting solid was then extracted with chlorobenzene to yield 111.0 mg of the target polymer (polymer P2-2F, shown in the figure), in a 91% yield.

[0181] The structural characterization data are as follows:

[0182] Molecular weight: GPC:M n =81.2 kDa, PDI=2.52, n=67;

[0183] Elemental analysis: C 74 H 108 F2N4O2S3, calculated values: C72.86, H8.92, N4.59, S7.88; found values: C73.24, H8.82, N4.47, S7.70;

[0184] From the above, we know that the structure of the compound is correct, and it is polymer P2-2F.

[0185] Example 6

[0186] Spectral properties of polymers P1, P1-2F, P2, and P2-2F.

[0187] Figure 4 and Figure 5 These are the UV-visible absorption spectra of the chlorobenzene solutions and films of polymers P1, P1-2F, P2 and P2-2F prepared in Examples 2, 3, 4 and 5 of the present invention, respectively.

[0188] Depend on Figure 4 It can be seen that the polymer of the present invention exhibits strong absorption in the ultraviolet-visible region and the near-infrared region, indicating that the polymer molecules of the present invention have strong intramolecular charge transfer.

[0189] Depend on Figure 5 It can be seen that the polymer of the present invention exhibits strong ordered aggregation in the film.

[0190] Example 7

[0191] Thermal properties of polymers P1, P1-2F, P2, and P2-2F.

[0192] Figure 6 These are the thermogravimetric curves of polymers P1, P1-2F, P2, and P2-2F prepared in Examples 2, 3, 4, and 5 of the present invention, respectively.

[0193] Depend on Figure 6 It can be seen that the decomposition temperatures (5% loss) of the polymers P1, P1-2F, P2 and P2-2F of the present invention are all between 390° C. and 410° C., indicating that the polymers of the present invention have good thermal stability.

[0194] Example 8

[0195] Preparation and performance of OFETs of polymers P1, P1-2F, P2 and P2-2F.

[0196] Figure 7 、 Figure 8 、 Figure 9 and Figure 10 The transfer curves and output curves of OFETs prepared from polymers P1, P1-2F, P2 and P2-2F in Examples 2-5 of the present invention are shown in FIG. Figure 7-9 It can be seen that the OFETs prepared from the polymer of the present invention have excellent bipolar transport performance. The carrier mobility can be calculated by the following equation:

[0197] I DS =(W / 2L)C i μ(V G –V TH ) 2 (sat.,V DS =V G –V TH )

[0198] Among them, I DS is the drain current, μ is the carrier mobility, V G is the gate voltage, V TH is the threshold voltage, W is the channel width (1400 μm), L is the channel length (30 μm), C i is the capacitance of the insulator. DS ,sat) 1 / 2 V G Draw a graph and perform linear regression. The carrier mobility can be calculated from the slope of the regression line, and V can be obtained from the intercept point of the regression line and the X-axis. TH The device performances of the OFETs prepared in the above examples of the present invention are shown in Table 1.

[0199] The switching ratio can be determined by Figure 7 、 Figure 8 、 Figure 9 and Figure 10 The ratio of the maximum and minimum source-drain currents is obtained.

[0200] More than 10 organic field-effect transistor devices were prepared using the polymers P1, P1-2F, P2, and P2-2F of the present invention as semiconductor layers. These devices have stable performance, and their representative performance parameters are shown in Table 1:

[0201] Table 1 Performance of OFETs

[0202]

[0203] The above experimental results show that the quinone-type bithiophene azaisoindigo polymer represented by Formula I provided by the present invention is an excellent bipolar semiconductor material.

[0204] This invention is not limited to the reported four polymer materials, P1, P1-2F, P2, and P2-2F. By varying the substituents R and X, a series of novel quinone-type bithiophene azaisoindigo polymers can be obtained. Furthermore, the synthetic route provided in this invention is simple, requires few steps, offers high yields, and is suitable for large-scale synthesis. This has important guiding significance for the further development of high-performance bipolar polymer semiconductor materials.

[0205] The embodiments of the present invention are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas. At the same time, for those skilled in the art, according to the ideas of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A quinone-type bithiophene azaisoindigo polymer, characterized in that: Its structural formula is shown in Formula I: In the formula I, R is C5-C 80 One of the straight or branched alkyl groups; wherein X in the formula I is selected from fluorine or hydrogen; In the formula I, n is the number of repetitions of the polymer main chain unit, n is a natural number, and 5≤n≤200.

2. The polymer according to claim 1, characterized in that In the formula I, R is C 10 -C 50 One of the straight-chain or branched-chain alkyl groups; 10≤n≤100.

3. The polymer according to claim 2, characterized in that In the formula I, R is C 10 -C 30 One of the straight-chain or branched-chain alkyl groups; 40≤n≤67.

4. The polymer according to claim 3, characterized in that In the formula I, R is 2-decyltetradecyl or 4-decyltetradecyl; and n is 40, 46, 63 or 67.

5. The method for preparing the polymer of formula I according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: S1. In an inert atmosphere, the compound represented by Formula II is reacted with a lithium reagent and N,N,N',N'-tetramethylethylenediamine to form the corresponding lithium salt, which is then rapidly reacted with the compound represented by Formula III for a nucleophilic addition reaction to obtain the synthetic intermediate represented by Formula IV. Formulas II, III, and IV are as follows: X in the formula II is the same as X in the polymer represented by formula I, and R in the formula III is the same as R in the polymer represented by formula I; S2. In the presence of a reducing agent, the compound represented by formula IV is subjected to a reduction reaction to obtain an intermediate represented by formula V; the formula V is as follows: S3. In the presence of an oxidizing agent, the compound represented by formula V is subjected to a dehydrogenation reaction, and the reaction is completed to obtain a monomer represented by formula VI; the formula VI is as follows: S4. In an inert atmosphere, in the presence of a palladium catalyst and a phosphine ligand, the compound represented by Formula VI and the compound represented by Formula VII are subjected to a Stille copolymerization reaction to obtain a polymer represented by Formula I, wherein the formula VII is shown below:

6. The preparation method according to claim 5, characterized in that In the step S1: The lithium reagent is a 1.6M hexane solution of n-butyl lithium or a 2.5M hexane solution of n-butyl lithium; The molar ratio of the compound represented by formula II to the compound represented by formula III is 1:2.2-2.5; The lithium reagent and N,N,N',N'-tetramethylethylenediamine are used in the same amount, and the molar ratio of the two is 1:1; the molar ratio of the lithium reagent to the compound represented by formula II is 2.2-2.5:1; The generation of the corresponding lithium salt and the nucleophilic addition reaction in step S1 are carried out in anhydrous tetrahydrofuran solvent; the reaction temperature for generating the corresponding lithium salt is -35°C, and the reaction time is 0.5 to 2 hours; the nucleophilic addition reaction is started by stirring at -35°C for 30 minutes, then heated to 18-22°C, and the reaction time is 6 to 24 hours; the inert atmosphere in step S1 includes a nitrogen atmosphere or an argon atmosphere.

7. The preparation method according to claim 5, characterized in that In the step S2: The reducing agent is anhydrous stannous chloride or stannous chloride dihydrate; The molar ratio of the compound represented by formula V to the reducing agent is 1:5-10; The reaction temperature of the reduction reaction is 80-120° C., and the reaction time is 1-5 hours; The reduction reaction is carried out in a mixed solvent of glacial acetic acid and tetrahydrofuran, wherein the volume ratio of the glacial acetic acid to the tetrahydrofuran in the mixed solvent is 1:1-2.

8. The preparation method according to claim 5, characterized in that In the step S3: The oxidant is 2,3-dichloro-5,6-dicyanobenzoquinone; The molar ratio of the compound represented by formula V to the oxidant is 1:3-5; The reaction temperature of the dehydrogenation reaction is 18-22°C, and the reaction time is 0.5-5h; The dehydrogenation reaction is carried out in toluene solvent.

9. The preparation method according to claim 5, characterized in that In the step S4: The palladium catalyst includes tetrakis(triphenylphosphine)palladium or tris(dibenzylideneacetone)dipalladium; the phosphine ligand includes tri(o-tolyl)phosphine or triphenylphosphine; In the Stille copolymerization reaction, the molar ratio of the compound represented by formula VI, the compound represented by formula VII, the palladium catalyst and the phosphine ligand is 1:0.95-1.05:0.01-0.10:0.10-0.50, the reaction temperature is 90-120° C., and the reaction time is 24-72 hours. The Stille copolymerization reaction is carried out in a nitrogen atmosphere or an argon atmosphere; The reaction is carried out in toluene or chlorobenzene solvent.

10. Use of the polymer according to any one of claims 1 to 4, characterized in that: The polymer is used in preparing an organic field effect transistor, wherein the organic semiconductor layer of the organic field effect transistor is made of the polymer.

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