Diketopyrrolopyrrole-based conjugated small molecule compound and preparation and application thereof

Abstract

The invention belongs to the technical field of organic semiconductor materials, and discloses a conjugated small molecule compound based on diketopyrrolopyrrole and a preparation method and application thereof. The structural general formula of the diketopyrrolopyrrole-containing conjugated small molecule compound material provided by the invention is as shown in formula (V), and the material is novel in structure, clear in chemical structure, single in molecular weight and good in repeatability; meanwhile, the conjugated compound has ion and electron conductivity, adjustable electron energy level and high charge carrier mobility, and can be processed by a solution method. The n-type or bipolar mixed ion-electron conductor is applied to an organic electrochemical transistor, the performance is excellent when the n-type or bipolar mixed ion-electron conductor works in an accumulation mode, the transconductance performance is high, and the n-type or bipolar mixed ion-electron conductor has potential application prospects in the fields of biosensing, bionic synaptic devices and the like. # imgabs0 #

Description

Technical Field

[0001] This invention patent relates to the technical field of organic semiconductor materials, and particularly relates to a conjugated small molecule compound based on diketopyrrolopyrrole and its preparation and application. Background Art

[0002] Organic Electrochemical Transistor (OECT) has shown broad application prospects in chemical and biological sensing fields such as ion detection, physiological signal monitoring, and flexible wearable electronic devices due to its excellent biocompatibility, low operating voltage (<1V), and high sensitivity, etc., and has become a research hotspot in the scientific research field.

[0003] The design and optimization of the active layer material play a crucial role in improving the performance of OECT, and its structural innovation has significantly promoted the development of OECT technology. Diketopyrrolopyrrole (DPP) is widely regarded as one of the ideal units for constructing high-performance organic / polymer semiconductor materials due to its unique π-conjugated planar structure, strong intra / inter-molecular interaction forces, simple and efficient synthesis method, and the ability to introduce oligoethylene glycol chains through imide N atoms to regulate solubility, ion doping level, molecular packing mode, and film morphology, etc. In recent years, significant progress has been made in the research of DPP-based conjugated polymers in the field of OECT, showing excellent device performance (Li et al., Nat. Commun. 2022, 13, 5970; Tan et al., Adv. Mater. 2022, 34, 2202574; Luo et al., ACS Macro Lett. 2021, 10, 1061 - 1067; Chen et al., Nat. Mater. 2022, 21, 564 - 571; Huang et al., Nature, 2023, 613, 496 - 502). However, the inherent molecular weight polydispersity of polymer materials leads to poor batch repeatability, and the complex structure-activity relationship hinders the establishment of precise molecular design rules.

[0004] In contrast, small molecule semiconductors have the advantages of a clear molecular structure and small differences between batches, which are more conducive to establishing a "structure-property" relationship model. However, existing research shows that the application of DPP-based small molecules in OECT lags far behind. The μC* value of the n-type DPP small molecule OECT device first reported by Liu et al. is only 5.88 F cm-1V-1s-1 (Liu et al., Adv. Func. Mater. 2023, 33, 2300049), which is significantly lower than that of the polymer system; and the research on bipolar small molecule OECT materials is almost blank.

[0005] Therefore, it is of great significance to develop n-type / bipolar DPP-based small molecules with both high carrier mobility and efficient ion transport channels and establish their molecular design paradigms for promoting the diversified development of OECT materials and improving the consistency of device performance. Summary of the Invention

[0006] In order to overcome the above-mentioned deficiencies of the prior art, the primary object of the present invention is to provide a conjugated small molecule compound based on pyrrolopyrrole dione.

[0007] Another object of the present invention is to provide a synthesis method of the above-mentioned conjugated small molecule compound based on pyrrolopyrrole dione.

[0008] Another object of the present invention is to provide the application of the above-mentioned conjugated small molecule compound based on pyrrolopyrrole dione. The present invention provides the application of the above-mentioned conjugated small molecule compound based on pyrrolopyrrole dione in an organic electrochemical transistor.

[0009] The object of the present invention can be achieved by the following technical solutions:

[0010] The present invention provides a conjugated small molecule compound based on pyrrolopyrrole dione, and the conjugated small molecule compound has the following general structural formula:

[0011]

[0012] R1, R2, R3, R4, R5 and R6 are independently hydrogen, a polyether group, an alkyl polyether group or a halogen-substituted alkyl polyether group;

[0013] Linker is a linking group;

[0014] EG is an electron-withdrawing group;

[0015] X1 and X2 are independently O, S or Se.

[0016] Further, R1, R2, R3, R4, R5 and R6 are independently one of the following structures:

[0017]

[0018] Further, the electron-withdrawing group EG is one of the following structures:

[0019]

[0020] R7 is hydrogen, a polyether group or an alkyl polyether group;

[0021] X and Y are independently F, Cl or CH3.

[0022] Further, the linking group Linker is one of the following structures:

[0023]

[0024] Ra, Rb, Rc, and Rd are independently hydrogen, a polyether group, or an alkyl polyether group;

[0025] X is O, S, or Se.

[0026] The present invention also provides a method for preparing a conjugated small molecule compound based on pyrrolopyrrolidone, and the preparation method includes the following steps:

[0027] Under an inert gas protection environment, a compound with the general formula (I) and a compound with the general formula (II), or a compound with the general formula (III) and a compound with the general formula (IV), are obtained through a metal-catalyzed coupling reaction;

[0028]

[0029]

[0030] M in the general formula (II) and the general formula (III) is trimethyltin, tributyltin, a borate ester, or boric acid.

[0031] The present invention also provides an application of a conjugated small molecule compound based on pyrrolopyrrolidone, and the fields of the application include organic electrochemical transistors, biosensors, and biomimetic synaptic devices.

[0032] The above-mentioned conjugated small molecule compound based on pyrrolopyrrolidone, as a promising class of mixed conductor materials, has not been reported in the field of organic electrochemical transistors so far. The present invention synthesizes this type of bipolar / n-type small molecule ion-electron conductor material for the first time and applies it to organic electrochemical transistors, achieving good device performance.

[0033] The beneficial effects that this application can produce are as follows:

[0034] The conjugated small molecule compound based on pyrrolopyrrolidone of the present invention has a novel structure, high carrier mobility, good ion doping / transport performance, adjustable electronic energy levels, and can be processed by solution method; when applied to organic electrochemical transistors as an n-type or bipolar material, it operates in the accumulation mode and can achieve high transconductance (>50 mS) at an ultra-low operating voltage of <1V, meeting the core requirements of bioelectronic devices for low power consumption and high-sensitivity signal amplification. Description of the Drawings

[0035] Figure 1The p-type transfer / transconductance curve of the OECT device based on the conjugated small molecule compound 2gDPP-V-RD.

[0036] Figure 2 The n-type transfer / transconductance curve of the OECT device based on the conjugated small molecule compound 2gDPP-V-RD. Detailed implementation mode

[0037] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0038] Embodiment 1

[0039] Preparation of the DPP-based conjugated small molecule compound 2gDPP-V-RD

[0040] The synthesis route of the conjugated compound 2gDPP-V-RD is as follows:

[0041]

[0042] (1) Preparation of compound C1-2

[0043] Under a nitrogen atmosphere, 1 g of compound C1-1 (1 equivalent) and 40 ml of anhydrous chloroform were added to a 100 ml reaction flask. 0.43 g of N-bromosuccinimide (1.2 equivalents) was added in batches, and the reaction was carried out at room temperature overnight. After the reaction was completed, water was added, and the mixture was extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, filtered, and the solvent was removed by rotary evaporation. Then, it was separated and purified by silica gel column chromatography to obtain 0.52 g of compound C1-2 (yield 45%).

[0044] 1H NMR (600 MHz, Chloroform-d, 300 K) δ (ppm) 8.74 (d, J = 3.8 Hz, 1H), 8.46 (dd, J = 4.1, 2.0 Hz, 1H), 7.64 (d, J = 5.0 Hz, 1H), 7.25 (d, J = 1.9 Hz, 1H), 7.20 (t, J = 2.1 Hz, 1H), 4.27 (t, J = 6.3 Hz, 2H), 4.19 (t, J = 6.1 Hz, 2H), 3.80–3.76 (m, 4H), 3.62 (dp, J = 6.9, 2.4 Hz, 4H), 3.48 (dt, J = 6.1, 2.5 Hz, 4H), 3.32 (dd, J = 4.1, 1.9 Hz, 6H).

[0045] (2) Preparation of Compound C1-3

[0046] Under a nitrogen atmosphere, 0.5 g of Compound C1-2 (1 equivalent), 0.25 g of Compound IM1 (1.2 equivalents), 1.89 g of K2CO3 (16 equivalents), 0.15 g of tetrakis(triphenylphosphine)palladium (0.15 equivalent) and 20 ml of anhydrous toluene were added to a 100 ml reaction flask, and the reaction was carried out at 100 °C for 24 h. After the reaction was completed, it was cooled to room temperature, water was added, and the mixture was extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, filtered, and the solvent was removed by distillation under reduced pressure. Then, it was separated and purified by silica gel column chromatography to obtain 0.41 g of Compound C1-3 (yield 77%).

[0047] 1H NMR (400 MHz, Chloroform-d, 300 K) δ (ppm) 9.89 (s, 1H), 8.78 (dd, J = 4.0, 1.1 Hz, 1H), 8.72 (d, J = 4.2 Hz, 1H), 7.71 (d, J = 4.0 Hz, 1H), 7.66 (dd, J = 5.0, 1.1 Hz, 1H), 7.46 (d, J = 4.1 Hz, 1H), 7.41 (d, J = 4.0 Hz, 1H), 7.29–7.26 (m, 1H), 4.28 (q, J = 6.6 Hz, 4H), 3.81 (q, J = 6.3 Hz, 4H), 3.66–3.61 (m, 4H), 3.49 (ddd, J = 6.5, 3.0, 2.0 Hz, 4H), 3.32 (d, J = 3.6 Hz, 6H).

[0048] (3) Preparation of Compound C1-4

[0049] Under a nitrogen atmosphere, 0.44 g of Compound C1-3 (1 equivalent) and 20 ml of anhydrous chloroform were added to a 100 ml reaction flask, and 0.19 g of N-bromosuccinimide (1.5 equivalents) was added in portions. The reaction was carried out at room temperature overnight. After the reaction was completed, water was added, and the mixture was extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, filtered, and the solvent was removed by distillation under reduced pressure to obtain 0.33 g of Compound C1-4 (crude yield 73%), which was directly used in the next step.

[0050] (4) Preparation of Compound C1-5

[0051] Under a nitrogen atmosphere, 0.33 g of Compound C1-4 (1 equivalent), 154 mg of 3-ethylrhodanine (1.8 equivalents) and 20 ml of anhydrous chloroform were added to a 100 ml reaction flask, and a few drops of triethylamine were added. The reaction was carried out at 70 °C overnight. After the reaction was completed, water was added, and the mixture was extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, filtered, and the solvent was removed by distillation under reduced pressure. Then, it was separated and purified by silica gel column chromatography to obtain 0.245 g of Compound C1-5 (yield 62%).

[0052] 1H NMR (600 MHz, Chloroform-d, 300 K) δ (ppm) 8.77 (d, J = 4.1 Hz, 1H), 8.51 (d, J = 4.1 Hz, 1H), 7.82 (s, 1H), 7.40 (dd, J = 8.0, 4.0 Hz, 2H), 7.35 (d, J = 4.1 Hz, 1H), 7.21 (d, J = 4.1 Hz, 1H), 4.28 (t, J = 6.2 Hz, 2H), 4.22–4.16 (m, 4H), 3.80 (dt, J = 12.4, 6.1 Hz, 4H), 3.66–3.61 (m, 4H), 3.49 (tt, J = 6.3, 3.7 Hz, 4H), 3.33 (d, J = 5.2 Hz, 6H), 1.30 (t, J = 7.2 Hz, 3H).

[0053] (5) Preparation of Compound 2gDPP-V-RD

[0054] Under a nitrogen atmosphere, 85 mg of Compound C1-5 (2.4 equivalents), 25 mg of Compound IM2 (1 equivalent), 1.92 mg of tris(dibenzylideneacetone)dipalladium, 3.96 mg of tris(o-tolyl)phosphine and 3 ml of anhydrous toluene were added to a 10 ml reaction flask, and the reaction was carried out at 110 °C for 24 - 48 h. After the reaction was completed and cooled to room temperature, it was dropped into methanol to precipitate a solid, filtered, washed successively with methanol and dichloromethane, and dried to obtain 50 mg of Compound 2gDPP-V-RD (yield 77%). Calculated for C70H70N6O14S10: 1538.216, found: 1538.186.

[0055] Example 2

[0056] Preparation of DPP-based Conjugated Small Molecule Compound 3gDPP-V-RD

[0057] The synthetic route of the conjugated compound 3gDPP-V-RD is as follows:

[0058]

[0059] (1) Preparation of Compound C2-2

[0060] Under a nitrogen atmosphere, 1 g of Compound C2-1 (1 equivalent) and 40 ml of anhydrous chloroform were added to a 100 ml reaction flask, and 0.36 g of N-bromosuccinimide (1.2 equivalents) was added in portions, and the reaction was carried out at room temperature overnight. After the reaction was completed, water was added, extracted with dichloromethane, the organic phase was dried over anhydrous sodium sulfate, filtered, the solvent was removed by reduced pressure distillation, and then separated and purified by a silica gel column chromatography to obtain 0.45 g of Compound C2-2 (yield 40%).

[0061] 1H NMR (400 MHz, Chloroform-d, 300 K) δ (ppm) 8.75 (dd, J = 3.9, 1.1 Hz, 1H), 8.48 (d, J = 4.1 Hz, 1H), 7.65 (dd, J = 5.0, 1.1 Hz, 1H), 7.25 (t, J = 3.8 Hz, 1H), 7.20 (d, J = 4.1 Hz, 1H), 4.26 (t, J = 6.3 Hz, 2H), 4.18 (t, J = 6.0 Hz, 2H), 3.81–3.75 (m, 4H), 3.66–3.61 (m, 4H), 3.60–3.55 (m, 8H), 3.51–3.46 (m, 4H), 3.34 (s, 6H).

[0062] (2) Preparation of Compound C2-3

[0063] Under a nitrogen atmosphere, 0.62 g of Compound C2-2 (1 equivalent), 0.26 g of Compound IM1 (1.2 equivalents), 2.04 g of K2CO3 (16 equivalents), 0.16 g of tetrakis(triphenylphosphine)palladium (0.15 equivalent) and 40 ml of anhydrous toluene were added to a 100 ml reaction flask, and the reaction was carried out at 100 °C for 24 h. After the reaction was completed, it was cooled to room temperature, water was added, and the mixture was extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, filtered, and the solvent was removed by distillation under reduced pressure. Then, it was separated and purified by silica gel column chromatography to obtain 0.5 g of Compound C2-3 (yield 70%).

[0064] 1H NMR (400 MHz, Chloroform-d, 300 K) δ (ppm) 9.90 (s, 1H), 8.79 (dd, J = 4.0, 1.2 Hz, 1H), 8.72 (d, J = 4.2 Hz, 1H), 7.71 (d, J = 4.0 Hz, 1H), 7.66 (dd, J = 5.0, 1.2 Hz, 1H), 7.46 (d, J = 4.2 Hz, 1H), 7.41 (d, J = 4.0 Hz, 1H), 7.29–7.26 (m, 1H), 4.27 (dt, J = 7.6, 6.2 Hz, 4H), 3.80 (q, J = 6.3 Hz, 4H), 3.65 (ddt, J = 6.6, 4.0, 1.2 Hz, 4H), 3.58 (dddd, J = 11.5, 6.9, 3.5, 2.1 Hz, 8H), 3.51–3.45 (m, 4H), 3.33 (d, J = 8.2 Hz, 6H).

[0065] (3) Preparation of Compound C2-4

[0066] Under a nitrogen atmosphere, 0.41 g of compound C2-3 (1 equivalent) and 20 ml of anhydrous chloroform were added to a 100 ml reaction flask. 0.13 g of N-bromosuccinimide (1.2 equivalents) was added in portions, and the reaction was carried out at room temperature overnight. After the reaction was completed, water was added, and the mixture was extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, filtered, and the solvent was removed by distillation under reduced pressure to obtain 0.39 g of compound C2-4 (crude yield 85%), which was directly used in the next step.

[0067] (4) Preparation of compound C2-5

[0068] Under a nitrogen atmosphere, 0.39 g of compound C2-4 (1 equivalent), 121 mg of 3-ethyl rhodanine (1.2 equivalents) and 30 ml of anhydrous chloroform were added to a 100 ml reaction flask. A few drops of triethylamine were added, and the reaction was carried out at 70 °C overnight. After the reaction was completed, water was added, and the mixture was extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, filtered, and the solvent was removed by distillation under reduced pressure. Then, it was separated and purified by silica gel column chromatography to obtain 0.36 g of compound C2-5 (yield 78%).

[0069] 1H NMR (400 MHz, Chloroform-d, 300 K) δ (ppm) 8.78 (d, J = 4.2 Hz, 1H), 8.52 (d, J = 4.2 Hz, 1H), 7.82 (s, 1H), 7.43–7.38 (m, 2H), 7.35 (d, J = 4.1 Hz, 1H), 7.21 (d, J = 4.2 Hz, 1H), 4.27 (t, J = 6.1 Hz, 2H), 4.20 (t, J = 6.0 Hz, 4H), 3.80 (dt, J = 8.3, 6.0 Hz, 4H), 3.65 (td, J = 5.8, 3.5 Hz, 4H), 3.58 (ddt, J = 9.4, 6.1, 3.0 Hz, 8H), 3.48 (ddd, J = 11.4, 5.8, 3.4 Hz, 4H), 3.34 (d, J = 9.7 Hz, 6H), 1.30 (t, J = 7.1 Hz, 3H).

[0070] (5) Preparation of compound 3gDPP-V-RD

[0071] Under a nitrogen atmosphere, 90 mg of compound C2-5 (2.4 equivalents), 24 mg of compound IM2 (1 equivalent), tris(dibenzylideneacetone)dipalladium (1.83 mg), tris(o-tolyl)phosphine (3.65 mg) and 3 ml of anhydrous toluene were added to a 20 ml reaction flask. The reaction was carried out at 110 °C for 24 - 48 h. After the reaction was completed and cooled to room temperature, it was dropped into methanol to precipitate a solid, which was filtered. Then, it was separated and purified by silica gel column chromatography to obtain 55 mg of compound 3gDPP-V-RD (yield 81%).

[0072] 1H NMR (600 MHz, Chloroform-d, 300 K) δ (ppm) 8.92 (d, J = 4.0 Hz, 2H), 8.78 (d, J = 4.0 Hz, 2H), 7.63 (s, 2H), 7.27 (s, 2H), 7.23 (d, J = 4.0 Hz, 2H), 7.18 (d, J = 4.0 Hz, 2H), 7.15 (d, J = 4.1 Hz, 2H), 7.02 (s, 2H), 4.28–4.21 (m, 8H), 4.13 (q, J = 7.2 Hz, 4H), 3.82 (t, J = 6.5 Hz, 4H), 3.77 (t, J = 6.6 Hz, 4H), 3.70 (q, J = 5.0 Hz, 8H), 3.63 (q, J = 4.5 Hz, 8H), 3.59 (t, J = 4.7 Hz, 8H), 3.49 (q, J = 5.3 Hz, 8H), 3.34 (d, J = 2.3 Hz, 12H), 1.28 (t, J = 7.2 Hz, 6H).

[0073] Example 3

[0074] Preparation of DPP-based conjugated small molecule compound 4gDPP-V-RD

[0075] The synthetic route of conjugated compound 4gDPP-V-RD is as follows:

[0076]

[0077] (1) Preparation of compound C3-2

[0078] Under a nitrogen atmosphere, 0.37 g of compound C3-1 (1 equivalent) and 30 ml of anhydrous chloroform were added to a 100 ml reaction flask. 0.12 g of N-bromosuccinimide (1.2 equivalents) was added in portions, and the reaction was carried out at room temperature overnight. After the reaction was completed, water was added, and the mixture was extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, filtered, and the solvent was removed by distillation under reduced pressure. Then, it was separated and purified by silica gel column chromatography to obtain 0.19 g of compound C2 (yield 48%).

[0079] 1H NMR (400 MHz, CDCl3): δ = 8.76 (dd, 1H), δ = 8.48 (d, 1H), δ = 7.66 (dd, 1H), δ = 7.27 (d, 1H), δ = 7.21 (d, 1H), δ = 4.27 (t, 2H), δ = 4.19 (t, 2H), δ = 3.79 (t, 4H), δ = 3.65 - 3.57 (m, 20H), δ = 3.53 - 3.51 (m, 4H), δ = 3.36 (s, 6H).

[0080] (2) Preparation of compound C3-3

[0081] Under a nitrogen atmosphere, 0.2 g of compound C3-2 (1 equivalent), 76 mg of compound IM1 (1.2 equivalents), 0.58 g of K2CO3 (16 equivalents), 46 mg of tetrakis(triphenylphosphine)palladium (0.15 equivalent) and 20 ml of anhydrous toluene were added to a 100 ml reaction flask, and the reaction was carried out at 100 °C for 24 h. After the reaction was completed, it was cooled to room temperature, water was added, extracted with dichloromethane, the organic phase was dried over anhydrous sodium sulfate, filtered, the solvent was removed by distillation under reduced pressure, and then purified by silica gel column chromatography to obtain 0.16 g of compound C3-3 (yield 77%).

[0082] 1H NMR (400 MHz, CDCl3): δ = 9.90 (s, 1H), δ = 8.80 (dd, 1H), δ = 8.72 (d, 1H), δ = 7.72 (d, 1H), δ = 7.67 (dd, 1H), δ = 7.47 (d, 1H), δ = 7.42 (d, 1H), δ = 7.29 (d, 1H), δ = 4.30 (q, 4H), δ = 3.83 (q, 4H), δ = 3.66 - 3.57 (m, 20H), 3.53 - 3.49 (m, 4H), δ = 3.36 (d, 6H).

[0083] (3) Preparation of compound C3-4

[0084] Under a nitrogen atmosphere, 0.16 g of compound C3-3 (1 equivalent) and 20 ml of anhydrous chloroform were added to a 100 ml reaction flask, and 44 mg of N-bromosuccinimide (1.2 equivalents) was added in portions, and the reaction was carried out at room temperature overnight. After the reaction was completed, water was added, extracted with dichloromethane, the organic phase was dried over anhydrous sodium sulfate, filtered, the solvent was removed by distillation under reduced pressure to obtain 0.11 g of compound C3-4 (crude yield 62%), and it was directly used for the next step.

[0085] (4) Preparation of compound C3-5

[0086] Under a nitrogen atmosphere, 0.21 g of compound C3-4 (1 equivalent), 47 mg of 3-ethylrhodanine (1.2 equivalents) and 20 ml of anhydrous chloroform were added to a 100 ml reaction flask, and a few drops of triethylamine were added, and the reaction was carried out at 70 °C overnight. After the reaction was completed, water was added, extracted with dichloromethane, the organic phase was dried over anhydrous sodium sulfate, filtered, the solvent was removed by distillation under reduced pressure, and then purified by silica gel column chromatography to obtain 0.17 g of compound C3-5 (yield 70%).

[0087] 1H NMR (400 MHz, CDCl3): δ = 8.78 (d, 1H), δ = 8.52 (d, 1H), δ = 7.83 (s, 1H), δ = 7.42 (q, 2H), δ = 7.37 (d, 1H), δ = 7.22 (d, 1H), δ = 4.28 (t, 2H), δ = 4.22 - 4.16 (m, 4H), δ = 3.82 - 3.77 (m, 4H), δ = 3.66 - 3.57 (m, 20H), δ = 3.54 - 3.50 (m, 4H), δ = 3.36 (d, 6H), δ = 1.31 (t, 3H).

[0088] (5) Preparation of Compound 4gDPP-V-RD

[0089] Under a nitrogen atmosphere, 66 mg of Compound C3-5 (2.2 equivalents), 17.9 mg of Compound IM2 (1 equivalent), tris(dibenzylideneacetone)dipalladium (3 mg), tris(o-tolyl)phosphine (6.1 mg) and 5 ml of anhydrous toluene were added to a 20 ml reaction flask, and the reaction was carried out at 110 °C for 24 - 48 h. After the reaction was completed and cooled to room temperature, it was dropped into methanol to precipitate a solid, filtered, and then separated and purified by a silica gel column chromatography to obtain 37 mg of Compound 4gDPP-V-RD (yield 67%).

[0090] 1H NMR (400 MHz, Chloroform-d) δ 8.94 (s, 2H), 8.83 (s, 2H), 7.72 (s, 2H), 7.17 (d, J = 38.8 Hz, 2H), 4.30 (s, 8H), 4.18 (d, J = 7.3 Hz, 4H), 3.95–3.48 (m, 56H), 3.38 (s, 12H), 1.32 (s, 6H).

[0091] Example 4

[0092] Preparation of DPP-based Conjugated Small Molecule Compound 4gDPP-C-RD

[0093] The synthetic route of the conjugated compound 4gDPP-C-RD is as follows:

[0094]

[0095] Under a nitrogen atmosphere, 64 mg of compound C3-5 (2.2 equivalents) in Example 3, 16.6 mg of compound IM2 (1 equivalent), tris(dibenzylideneacetone)dipalladium (3.5 mg), tris(o-tolyl)phosphine (7.5 mg) and 5 ml of anhydrous toluene were added to a 20 ml reaction flask, and the reaction was carried out at 110 °C for 24 - 48 h. After the reaction was completed and cooled to room temperature, it was dropped into methanol to precipitate a solid, filtered, and then purified by silica gel column chromatography to obtain 31 mg of compound 4gDPP-V-RD (yield 53%).

[0096] 1H NMR (400 MHz, Chloroform-d) δ 8.79 (d, J = 4.2 Hz, 2H), 8.68 (d, J = 4.1 Hz, 2H), 7.83 (s, 2H), 7.42 (dd, J = 7.0, 4.1 Hz, 4H), 7.35 (dd, J = 7.7, 4.1 Hz, 4H), 4.24 (dt, J = 26.8, 6.7 Hz, 12H), 3.79 (dt, J = 9.5, 6.0 Hz, 8H), 3.65–3.56 (m, 40H), 3.53–3.49 (m, 8H), 3.35 (d, J = 3.6 Hz, 12H), 1.30 (t, J = 7.1 Hz, 6H).

[0097] Example 5

[0098] Preparation of Organic Electrochemical Transistor Devices

[0099] The preparation process of the OECT device includes the patterning of gold electrodes and the deposition of a small molecule mixed conductor material in the channel. First, the glass substrate was cleaned successively with acetone, isopropyl alcohol, a sulfuric acid-hydrogen peroxide mixture ((volume ratio 7:3)), and deionized water, and then dried with a nitrogen gun. Gold electrodes were deposited on the substrate using photolithography and vacuum thermal evaporation coating techniques. The channel width (W) of the device was 39000 μm, and the length (L) was 20 μm. A 5 mg / ml solution of compound 2gDPP-V-RD in hexafluoroisopropanol was prepared, and the semiconductor layer was deposited in the channel by spin coating. A 0.1 M KPF6 solution and an Ag / AgCl electrode were used as the electrolyte solution and the gate, respectively. The electrical properties of the prepared device were tested using a semiconductor parameter analyzer under ambient conditions.

[0100] Figure 1 is the p-type transfer / transconductance curve of the OECT device based on the small molecule 2gDPP-V-RD; Figure 2 is the n-type transfer / transconductance curve of the OECT device based on compound 2gDPP-V-RD. It can be seen from the figure that this compound is a bipolar mixed conductor with good device performance. The maximum transconductance of the p / n type exceeds 50 mS, and the output current reaches the mA level.

[0101] The above is a specific description of the preferred embodiment of the present invention. However, the present invention is not limited to the described embodiment. Those skilled in the art can make various equivalent deformations or substitutions without departing from the spirit of the present invention, and these equivalent deformations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A conjugated small molecule compound based on diketopyrrolopyrrole, characterized in that: The conjugated small molecule compound has the following general structural formula: The R1, R2, R3, R4, R5 and R6 are independently hydrogen, a polyether group, an alkyl polyether group or a halogen-substituted alkyl polyether group; The Linker is a connecting group; The EG is an electron withdrawing group; The X1 and X2 are independently O, S or Se.

2. A conjugated small molecule compound based on diketopyrrolopyrrole according to claim 1, characterized in that: The R1, R2, R3, R4, R5 and R6 are independently one of the following structures:

3. A conjugated small molecule compound based on diketopyrrolopyrrole according to claim 1, characterized in that: The electron withdrawing group EG is one of the following structures: R7 is hydrogen, a polyether group or an alkyl polyether group; Said X and Y are independently F, Cl or CH3.

4. A conjugated small molecule compound based on diketopyrrolopyrrole according to claim 1, characterized in that: The linker is one of the following structures: The Ra, Rb, Rc and Rd are independently hydrogen, a polyether group or an alkyl polyether group; The X is O, S or Se.

5. A method for preparing a conjugated small molecule compound based on diketopyrrolopyrrole according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: Under an inert gas protection environment, a compound having the general formula (I) and a compound having the general formula (II), or a compound having the general formula (III) and a compound having the general formula (IV) are subjected to a metal-catalyzed coupling reaction to obtain; In the general formula (II) and the general formula (III), M is trimethyltin, tributyltin, boric acid ester or boric acid.

6. An application of a conjugated small molecule compound based on diketopyrrolopyrrole as claimed in any one of claims 1 to 4, characterized in that: The fields of application include organic electrochemical transistors, biosensors and biomimetic synaptic devices.

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