Non-fused ring electron acceptor material and method for preparing the same

Abstract

The application provides a non-fused electron acceptor material and a preparation method thereof, and a structural formula of the non-fused electron acceptor material is shown in general formula I; wherein, a core group comprises a benzotri furan unit, end groups comprise halogen-substituted 3-(dicyanomethylene) indene-1-ketone units, and a pi bridge between the end groups and the core group comprises an alkyl-substituted five-membered heterocyclic unit; (I); in formula I, X1 and X2 are each independently selected from fluorine, chlorine or bromine; Y is selected from oxygen, sulfur or selenium; R is selected from C2~C 400 A straight-chain or branched alkyl group. The material realizes conformational locking without an alkoxy substitution by utilizing an oxygen atom effect, stably maintains a low HOMO energy level while ensuring molecular planarity, and thus significantly improves compatibility with various donor materials.

Description

Technical Field

[0001] This application belongs to the field of organic optoelectronic functional materials, and in particular relates to a non-fused ring electron acceptor material and its preparation method. Background Technology

[0002] In recent years, non-fused-ring electron acceptors have gradually become a research hotspot to replace traditional fused-ring acceptor systems due to their simple synthetic routes, strong structural tunability, and potential advantages in low cost and large-scale preparation.

[0003] Despite the advantages mentioned above, non-fused ring systems still face challenges in improving their performance, mainly due to the lack of a rigid fused ring framework, which results in greater molecular conformational freedom, weaker intermolecular packing, and lower charge transport efficiency.

[0004] To address this issue, related technologies have employed the introduction of alkoxy substituents to achieve conformational locking, thereby enhancing molecular planarity and π-π packing properties. However, this strategy simultaneously strengthens the molecule's electron-donating ability, raising the highest occupied molecular orbital (HOMO) energy level. This leads to a deterioration in energy level matching with commonly used donor materials (such as PM6 and D18), limiting the material's versatility. This trade-off between conformational rigidity and energy level matching has become a key bottleneck in the design of non-fused-ring acceptors. Summary of the Invention

[0005] This application provides a non-fused-ring electron acceptor material and its preparation method. This material achieves conformational locking without alkoxy substitution by utilizing the oxygen heteroatom effect. While ensuring molecular planarity, it stably maintains a low HOMO energy level, thereby significantly improving compatibility with a variety of donor materials.

[0006] To achieve the above-mentioned objectives, the technical solution of this application is as follows: The first aspect of this application provides a non-fused-ring electron acceptor material, the structural formula of which is shown in general formula I; wherein, the core group includes a benzotrifuran unit, the terminal group includes a halogen-substituted 3-(dicyanomethylene)indene-1-one unit, and the π bridge between the terminal group and the core group includes an alkyl-substituted five-membered heterocyclic unit. (I); In Formula I, X1 and X2 are each independently selected from fluorine, chlorine, or bromine; Y is selected from oxygen, sulfur, or selenium; and R is selected from C2~C2. 400 Straight-chain or branched alkyl groups.

[0007] As can be seen from the above technical solutions, the non-fused-ring electron acceptor material provided in the first aspect of this application has a core group of benzotrifuran unit. This unit utilizes the oxygen heteroatom effect to suppress conformational torsion at the molecular level and maintains a low HOMO energy level, which significantly improves compatibility with various donor materials. Furthermore, on both sides of the core group are alkyl-substituted five-membered heterocyclic units with π-bridge groups. The connection between these units and the benzotrifuran unit presents a nearly completely coplanar structure at the lowest energy configuration. This coplanar structure can effectively improve the molecular stacking performance and charge transfer performance. Finally, on both sides of the π-bridge group, halogen-substituted 3-(dicyanomethylene)inden-1-one units are used as terminal electron-withdrawing groups, which promote the intramolecular push-pull electron effect, enhance intramolecular charge transfer, and improve the light absorption capacity of the material.

[0008] The second aspect of this application provides a method for preparing a non-fused-ring electron acceptor material, comprising the following steps: S1. Compound 1 and compound 2 are subjected to a tin-reaction to obtain compound 3; ; S2. Compound 3 and compound 4 are subjected to a Stille coupling reaction to obtain compound 5; ; S3. Compound 5 is subjected to an aldehyde substitution reaction to obtain compound 6; ; S4. Compound 6 and compound 7 are subjected to a condensation reaction to obtain a compound of general formula I; ; Among them, X1 and X2 are each independently selected from fluorine, chlorine, or bromine; Y is selected from oxygen, sulfur, or selenium; and R is selected from C2~C. 400 Straight-chain or branched alkyl groups.

[0009] As can be seen from the above technical solutions, the preparation method of the non-fused-ring electron acceptor material provided in the second aspect of this application has a simple synthetic route, controllable steps, mild conditions, and a single product with high purity, making it suitable for large-scale preparation. The non-fused-ring electron acceptor material prepared by this method is the non-fused-ring electron acceptor material described in the foregoing embodiments. Attached Figure Description

[0010] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic flowchart of a method for preparing non-fused-ring electron acceptor materials provided in some embodiments of this application; Figure 2 This is a schematic flowchart of a method for preparing non-fused-ring electron acceptor materials provided in other embodiments of this application. Detailed Implementation

[0012] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0013] The flowchart shown in the attached diagram is for illustrative purposes only and does not necessarily include all content and operations / steps, nor does it necessarily have to be performed in the order described. For example, some operations / steps can be broken down, combined, or partially merged, so the actual execution order may change depending on the actual situation.

[0014] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0015] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0016] Related technologies achieve conformational locking by introducing alkoxy substituents, thereby improving molecular planarity and π-π packing properties. However, this strategy simultaneously enhances the molecule's electron-donating ability, raising the highest occupied molecular orbital (HOMO) energy level, leading to a deterioration in energy level matching with commonly used donor materials (such as PM6 and D18), thus limiting the material's versatility. This "trade-off between conformational rigidity and energy level matching" has become a key bottleneck problem in the design of non-fused-ring acceptors.

[0017] Therefore, embodiments of this application propose a non-fused-ring electron acceptor material and its preparation method, aiming to solve the aforementioned technical problems.

[0018] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0019] This application provides a non-fused-ring electron acceptor material, the structural formula of which is shown in general formula I; wherein, the core group includes a benzotrifuran unit, the terminal group includes a halogen-substituted 3-(dicyanomethylene)indene-1-one unit, and the π-bridge between the terminal group and the core group includes an alkyl-substituted five-membered heterocyclic unit. (I); In Formula I, X1 and X2 are each independently selected from fluorine, chlorine, or bromine; Y is selected from oxygen, sulfur, or selenium; and R is selected from C2~C2. 400 Straight-chain or branched alkyl groups.

[0020] In this application, the number of carbon atoms in a straight-chain or branched alkyl group can be any integer between 2, 10, 20, 30, 50, 60, 100, 150, 200, 220, and 400. Specific examples of straight-chain alkyl groups include, but are not limited to: ethyl, n-butyl, n-octyl, n-decyl, n-dodecyl, n-hexadecyl, n-eicosyl, and n-trianediyl; specific examples of branched alkyl groups include, but are not limited to: isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, isooctyl, 3-ethylheptane, and 2-ethylhexyl. In some further embodiments, R is selected from C2~C6. 50 Straight-chain or branched alkyl groups.

[0021] As can be seen from the above technical solutions, the non-fused-ring electron acceptor material proposed in this application has a core group of benzotrifuran unit. This unit utilizes the oxygen heteroatom effect to suppress conformational torsion at the molecular level and maintains a low HOMO energy level, significantly improving compatibility with various donor materials. Furthermore, on both sides of the core group are alkyl-substituted five-membered heterocyclic units with π-bridge groups. The connection between these units and the benzotrifuran unit exhibits a nearly completely coplanar structure at the lowest energy configuration. This coplanar structure can effectively improve the molecular stacking performance and charge transfer performance. Finally, on both sides of the π-bridge group, halogen-substituted 3-(dicyanomethylene)inden-1-one units are used as terminal electron-withdrawing groups, promoting the intramolecular push-pull electron effect, enhancing intramolecular charge transfer, and improving the light absorption capacity of the material. In some embodiments of this application, the non-fused-ring electron acceptor material is selected from compounds represented by formula A1 or A2; or .

[0022] The compound shown in A1 has a core group benzotrifuran, a π-bridge group (2-ethylhexyl)thiophene, and a terminal group 5,6-difluoro-3-(dicyanomethylene)indone; the compound shown in A2 has a core group benzotrifuran, a π-bridge group (2-ethylhexyl)thiophene, and a terminal group 5,6-dichloro-3-(dicyanomethylene)indone. Therefore, the non-fused-ring electron acceptor materials of the two structures in the above embodiments have the advantage of using the oxygen heteroatom effect to intrinsically suppress conformational torsion at the molecular level and the furan-thiophene linkage exhibiting a nearly completely coplanar structure at the lowest energy configuration.

[0023] Figure 1 This is a schematic flowchart illustrating the preparation method of non-fused-ring electron acceptor materials provided in some embodiments of this application.

[0024] like Figure 1 As shown, the preparation method of the non-fused ring electron acceptor material includes steps S1 to S4.

[0025] Step S1: Compound 1 and Compound 2 are subjected to a tin-reaction reaction to obtain Compound 3; .

[0026] Specifically, compound 1 (i.e., benzo[1,2]) b:3,4 b′:5,6 [b″] Trifuran was dissolved in tetrahydrofuran solution, and a hexane solution of n-butyllithium was added dropwise at -10℃ to 5℃. The mixture was stirred at 15℃ to 30℃ for 0.5h to 3h, and then the system was cooled to -90℃ to -60℃. Compound 2 (i.e., trimethyltin chloride) was added, and the reaction was carried out at -10℃ to 5℃ for 1h to 5h. After the reaction was completed, the mixture was quenched with water, and purified by extraction and methanol precipitation to obtain compound 3 (i.e., 2,5,8). Tris(trimethyltinyl)benzo[1,2] b:3,4 b′:5,6 b″] Trifuran).

[0027] It should be noted that step S1 is a multi-site lithiation reaction of the benzotrifuran core. Directed lithiation occurs under the action of n-butyllithium reagent to generate a lithium salt intermediate, which is then reacted with trimethyltin chloride to successfully introduce three trimethyltin groups onto the benzotrifuran unit.

[0028] The molar ratio of compound 1 to compound 2 is 1:(3~6), for example, including 1:3, 1:3.2, 1:3.5, 1:4, 1:4.3, 1:4.5, 1:5, 1:5.5, 1:6, etc. In the reaction process of step S1, by making compound 2 in excess, it can be ensured that compound 1 reacts fully, thereby increasing the reaction yield of compound 3.

[0029] In some embodiments, before step S1, the method further includes: step S0, performing a nucleophilic addition reaction on compound a1 to obtain compound 1; .

[0030] Specifically, compound a1 (i.e., ((2,4,6-trifluorobenzene-1,3,5-triyl)tri(acetylene-2,1-diyl))tri(trimethylsilane)), cesium hydroxide monohydrate, and water were added to N,N-dimethylacetamide and reacted at 160℃~190℃ for 1h~3h. The system was then cooled to 20℃~30℃. After the reaction was completed, water was added to quench the reaction. Compound 1 was obtained by extraction and silica gel column chromatography.

[0031] It should be noted that step S0 is the deprotection reaction of the trimethylsilyl group under the action of cesium hydroxide. Cesium hydroxide, as a strong base, attacks the silicon atom, breaking the Si-C bond to generate a terminal alkyne intermediate. Subsequently, the terminal alkyne intermediate undergoes an intramolecular nucleophilic addition reaction to form a benzotrifuran unit.

[0032] Step S2: Compound 3 and compound 4 are subjected to a Stille coupling reaction to obtain compound 5; ; In the reaction formula, Y is selected from oxygen, sulfur, or selenium; R is selected from C2~C3. 400 Straight-chain or branched alkyl groups.

[0033] Specifically, under nitrogen protection, compound 3 (i.e., 2,5,8) was subjected to... Tris(trimethyltinyl)benzo[1,2] b:3,4 b′:5,6 Toluene was added to compound 4, Pd2(dba)3 and P-(o-tolyl)3, and the mixture was refluxed at 60℃~90℃ for 12h~18h. After the reaction was completed, water was added to quench the reaction, and compound 5 was obtained by extraction and silica gel column chromatography.

[0034] It should be noted that step S2 is a typical palladium-catalyzed Stille coupling reaction used to construct CC bonds. The reaction mechanism is as follows: the organic halide undergoes an oxidative addition reaction with Pd(0) to generate a Pd(II) intermediate. Subsequently, the organotin reagent transfers the organic group to the palladium center through transmetalation. Finally, a new CC bond is formed through reduction elimination, while the Pd(0) catalyst is regenerated, completing the catalytic cycle.

[0035] The molar ratio of compound 3 to compound 4 is 1:(4~10), for example, 1:4, 1:4.3, 1:4.5, 1:5, 1:5.3, 1:5.5, 1:6, 1:6.1, 1:7, 1:8, 1:9, 1:10, etc. During the reaction in step S2, it is necessary to ensure that the amount of compound 4 is sufficient so that compound 3 can react fully and increase the yield of compound 5.

[0036] Furthermore, the molar ratio of compound 3, Pd2(dba)3, and P-(o-tolyl)3 is 1:(0.01~0.1):(0.1~0.5), including, for example, 1:0.01:0.1, 1:0.02:0.1, 1:0.04:0.2, 1:0.05:0.2, 1:0.05:0.3, 1:0.06:0.4, 1:0.08:0.45, 1:0.1:0.5, etc. Among them, Pd2(dba)3 palladium catalyst and P-(o-tolyl)3 palladium catalyst ligand can regulate the activity of palladium catalyst. By controlling the amount of Pd2(dba)3 and P-(o-tolyl)3, the palladium catalyst is ensured to have high activity, effectively promoting the C-C bond cross-coupling reaction of compound 3 and compound 4.

[0037] Step S3: Compound 5 is subjected to an aldehyde substitution reaction to obtain compound 6; ; In the reaction formula, Y is selected from oxygen, sulfur, or selenium; R is selected from C2~C3. 400 Straight-chain or branched alkyl groups.

[0038] Specifically, at -10℃ to 0℃, phosphorus oxychloride was dissolved in anhydrous N,N-dimethylformamide and stirred for 05h to 2h to obtain an aldehyde oxidizing agent; compound 5 was dissolved in 1,2-dichloroethane solution, and the aldehyde oxidizing agent was added dropwise to the 1,2-dichloroethane solution of compound 5 at -10℃ to 0℃. After stirring for 20min to 50min, the system was heated to 60℃ to 90℃ and reacted for 12h to 18h. After the reaction was completed, sodium hydroxide solution was added to quench the reaction, and compound 6 was obtained by extraction and silica gel column chromatography purification.

[0039] It should be noted that step S3 is the reaction of introducing an aldehyde group onto the thiophene ring, which is a typical Vilsmeier-Haack reaction. The reaction mechanism is as follows: N,N-dimethylformamide reacts with phosphorus oxychloride to generate a highly active Vilsmeier reagent (i.e., an aldehyde oxidizing agent). This reagent acts as an electrophilic agent to attack the active site of the thiophene ring, forming an imine salt intermediate, which is then hydrolyzed to obtain the corresponding aldehyde product.

[0040] Step S4: Compound 6 and compound 7 undergo a condensation reaction to obtain a compound of general formula I; ; In the reaction formula, X1 and X2 are each independently selected from fluorine, chlorine, or bromine; Y is selected from oxygen, sulfur, or selenium; and R is selected from C2~C2. 400 Straight-chain or branched alkyl groups.

[0041] Specifically, chloroform was added to compounds 6, 7 and pyridine, and the mixture was refluxed at 60°C to 90°C for 1 to 3 hours. After the reaction was completed, the mixture was concentrated and purified by silica gel column chromatography to obtain compounds of general formula I.

[0042] It should be noted that step S4 is a Knoevenagel condensation reaction between the aldehyde group of compound 6 and compound 7 (the active methylene compound), used to introduce the end group structure. This reaction, using pyridine as a weak base catalyst, successfully constructed the conjugated extended target molecule through condensation and dehydration.

[0043] The molar ratio of compound 6 to compound 7 is 1:(8~15), for example, including 1:8, 1:8.2, 1:8.5, 1:9, 1:9.5, 1:10, 1:11, 1:12, 1:12.5, 1:13, 1:14, 1:15, etc. In the reaction process of step S4, by making compound 7 in excess, it can be ensured that compound 6 reacts fully, thereby increasing the reaction yield of the compound of general formula I.

[0044] As can be seen from the above technical solutions, the preparation method of the non-fused-ring electron acceptor material proposed in this application has a simple synthetic route, controllable steps, mild conditions, and a single product with high purity, making it suitable for large-scale preparation. The non-fused-ring electron acceptor material prepared by this method is the non-fused-ring electron acceptor material described in the aforementioned embodiments.

[0045] Unless otherwise specified, the reagents and solvents used in the embodiments of this application are all commercially available.

[0046] To enable those skilled in the art to clearly understand the above-described implementation details and operations, and to demonstrate the significant advancements in the performance of the non-fused-ring electron acceptor materials and their preparation methods in the embodiments of this application, the following examples illustrate the above technical solutions.

[0047] Example 1 The structural formula of the non-fused-ring electron acceptor material in this embodiment is: Let it be denoted as A1.

[0048] refer to Figure 1 The preparation method of the non-fused-ring electron acceptor material A1 includes the following steps: Step S1: Compound 1 and Compound 2 are subjected to a tin-reaction reaction to obtain Compound 3; ; At 0°C, compound 1 (i.e., benzo[1,2]) was subjected to treatment. b:3,4 b′:5,6 [b″] Trifuran (1.51 mmol) was added dropwise to a tetrahydrofuran (THF) (22.5 mL) solution, followed by n-butyllithium (n-BuLi) (2.5 M hexane solution, 2.7 mL). The mixture was stirred at 22°C for 1 h, then cooled to -78°C. Compound 2 (i.e., trimethyltin chloride (Me3SnCl)) (6.81 mmol) was added, and the mixture was stirred at 0°C for 2 h. After the reaction was complete, the mixture was quenched with water (20 mL) and extracted three times with chloroform (CHCl3) (30 mL). The organic extract was dried over anhydrous sodium sulfate (Na2SO4), filtered, and concentrated under vacuum. The crude product was precipitated in methanol (MeOH), sonicated for 10 min, and cooled at 0°C. The resulting solid was filtered and washed with ice-cold MeOH to obtain compound 3 (2,5,8). Tris(trimethyltinyl)benzo[1,2] b:3,4 b′:5,6 b″] Trifuran was a white powder. The reaction mainly produced a single target product, but there was some product loss during the subsequent repeated precipitation and filtration. The product mass was 0.716 g, the amount of substance was 1.04 mmol, and the yield was 69%.

[0049] 1 HNMR spectrum and 13 CNMR spectroscopy confirmed that compound 3 was 2, 5, 8. Tris(trimethyltinyl)benzo[1,2] b:3,4 b′:5,6 b″] Trifuran. 1 HNMR spectrum and 13 The CNMR spectrum data are as follows: 1HNMR(CDCl3,500MHz): δ7.30(3H,s),0.44(27H,s)ppm; 13 C NMR (CDCl3, 125MHz): δ144.5, 130.1, 122.2, 119.8, -3.0.

[0050] Step S2: Compound 3 and compound 4 are subjected to a Stille coupling reaction to obtain compound 5; ; Under nitrogen atmosphere, compounds 3 (i.e., 2,5,8-tris(trimethyltinyl)benzo[1,2-b:3,4-b′:5,6-b″]trifuran) (0.054 mmol) and 4 (i.e., 2-bromo-4-(2-ethylhexyl)thiophene) were subjected to nitrogen atmosphere. Toluene (40 mL) was added to a mixture of Pd2(dba)3 (0.0027 mmol) and P-(o-tolyl)3 (3.3 mg, 0.0108 mmol). The resulting mixture was refluxed for 16 h. The reaction mixture was cooled and extracted with dichloromethane (CH2Cl2) and water. The aqueous layer was extracted twice with CH2Cl2. The combined organic layers were washed with brine, dried over anhydrous magnesium sulfate (MgSO4), and concentrated under reduced pressure. The crude mixture was purified by silica gel column chromatography using n-hexane (CH3(CH2)4CH3) / CH2Cl2 (5:95 v / v) as eluent to give compound 5 (i.e., 2,5,8). 3(4) (2 Ethylhexylthiophene 2 Benz[1,2] b:3,4 b′:5,6 b″]trifuran, a yellow solid, with a yield of 83%.

[0051] 1 HNMR spectrum and 13 CNMR spectroscopy confirmed that compound 5 was 2,5,8 3(4) (2 Ethylhexylthiophene 2 Benz[1,2] b:3,4 b′:5,6 b″] Trifuran. 1 HNMR spectrum and 13 The CNMR spectrum data are as follows: 1 HNMR(CDCl3,400MHz)δ(ppm):6.89(3H,s),6.76(3H,s),6.55(3H,s),2.52(6H,m),1.58(3H,m),1.28(24H,m),0.88(18H,m); 13 C NMR (CDCl3, 125 MHz): δ156.3, 138.5,134.2, 129.7, 124.8, 121.7, 121.2, 119.3, 42.9, 35.9, 32.2, 31.2, 29.8, 29.6,23.0, 14.1.

[0052] Step S3: Compound 5 is subjected to an aldehyde substitution reaction to obtain compound 6; ; At 0°C, phosphorus oxychloride (2 mL) was added to anhydrous N,N-dimethylformamide (DMF) (10 mL), and stirred for 1 h to obtain an aldehyde oxidizing agent. Compound 5 (i.e., 2,5,8) was then added to the solution. 3(4) (2 Ethylhexylthiophene 2 Benz[1,2] b:3,4 b′:5,6 [b″] Trifuran (0.19 mmol) was dissolved in 1,2-dichloroethane (15 mL). The aldehyde reagent was added dropwise to the 1,2-dichloroethane solution of compound 5 at 0°C. After stirring for 30 min, the system was heated to 85°C and reacted for 16 h. After the reaction was complete, 20 mL of sodium hydroxide (NaOH) (1 M) solution was added to quench the reaction. The reaction mixture was cooled and extracted with CH2Cl2 and water. The aqueous layer was extracted twice with CH2Cl2. The combined organic layers were washed with brine, dried over anhydrous MgSO4, and concentrated under reduced pressure. The crude mixture was purified by silica gel column chromatography using (CH3(CH2)4CH3) / CH2Cl2 (5:95 v / v) as the eluent to give compound 6 (i.e., 5,5′,5″). (benzo[1,2) b:3,4 b′:5,6 b″] Trifuran 2,5,8 Sanya Base) Three (3) (2 Ethylhexylthiophene 2 Formaldehyde, an orange solid, was produced with a yield of 89%.

[0053] 1 HNMR spectrum and 13 CNMR spectroscopy confirmed that compound 6 is 5,5′,5″. (benzo[1,2) b:3,4 b′:5,6 b″] Trifuran 2,5,8 Sanya Base) Three (3) (2 Ethylhexylthiophene 2 formaldehyde). 1 HNMR spectrum and 13 The CNMR spectrum data are as follows: 1 HNMR(CDCl3,400MHz)δ(ppm):9.80(3H,s),7.00(3H,s),7.20(3H,s),6.80(3H,s),2.52(6H,m),1.60(3H,m),1.28(24H,m),0.88(18H,m); 13 C NMR (CDCl3, 125 MHz): δ180.1, 156.0, 144.5, 140.9, 129.7, 127.3, 119.3, 118.2, 42.7, 35.8, 32.0,31.1, 29.8, 29.8, 23.5, 14.0.

[0054] Step S4: Compound 6 and compound 7 undergo a condensation reaction to obtain compound A1; ; To a mixture of compound 6 (i.e., 5,5′,5″-(benzo[1,2-b:3,4-b′:5,6-b″]trifuran-2,5,8-trimethylene)tris(3-(2-ethylhexyl)thiophene-2-carboxaldehyde) (0.046 mmol), compound 7 (i.e., 5,6-difluoro-3-(dicyanomethylene)indone) (0.46 mmol), and pyridine (1.5 mL), 15 mL of chloroform was added. The resulting mixture was refluxed for 2 h, concentrated after reflux, and purified by silica gel column chromatography using (CH3(CH2)4CH3) / CH2Cl2 (5:95 v / v) as eluent to give compound A1 (i.e., 2,2′,2″). ((2Z,2′Z,2″Z)-((benzo[1,2) b:3,4 b′:5,6 b″] Trifuran 2,5,8 Sanya Jisan (3) (2 Ethylhexylthiophene 5,2 Dimethylene subunit)) Tri(methylene subunit)) Tri(5,6 Difluoride 3 oxygen 2,3 Dihydrogen 1 Indene 2,1 Di(trimalonidonitrile) is a dark green solid with a yield of 67%.

[0055] 1 HNMR spectrum and 13 CNMR spectroscopy confirmed that compound A1 is 2,2′,2″. ((2Z,2′Z,2″Z)-((benzo[1,2) b:3,4 b′:5,6 b″] Trifuran 2,5,8 Sanya Jisan (3) (2 Ethylhexylthiophene 5,2 Dimethylene subunit)) Tri(methylene subunit)) Tri(5,6 Difluoride 3 oxygen 2,3 Dihydrogen 1 Indene 2,1 Di-subunit)trimalonitrile. 1 HNMR spectrum and 13 The CNMR spectrum data are as follows: 1 HNMR(CDCl3,400MHz)δ(ppm):7.48(3H,m),7.19(3H,m),7.08(3H,s),6.80(3H,s),2.42(6H,m),1.68(3H,m),1.28(24H,m),0.89(18H,m); 13C NMR (CDCl3, 125 MHz): δ190.5, 177.8, 156.0, 155.2, 150.2, 144.5, 142.0, 140.9, 135.7, 134.6, 134.5,129.7, 127.1, 119.9, 118.2, 116.2, 115.8, 115.7, 65.3, 41.4, 38.8, 32.0,31.9, 29.9, 29.8, 23.2, 16.1.

[0056] Example 2 The structural formula of the non-fused-ring electron acceptor material in this embodiment is: , denoted as A2.

[0057] refer to Figure 2 The preparation method of the non-fused ring electron acceptor material A2 includes steps S0 to S4, which are basically the same as the preparation method of Example 1, except for steps S0 and S4.

[0058] Step S0: Compound a1 undergoes a nucleophilic addition reaction to obtain compound 1; ; Compound a1 (i.e., ((2,4,6-trifluorobenzene-1,3,5-triyl)tris(ethynyl-2,1-diyl))tris(trimethylsilane)) (0.500 mmol), cesium hydroxide monohydrate (CsOH·H2O) (5.00 mmol), and water (5.0 mmol) were added to N,N-dimethylacetamide (DMAc) (5 mL). The reaction was carried out at 175 °C for 2 h, and then the system was cooled to 22 °C. After the reaction was completed, water (5 mL) was added to quench the reaction. The organic layer was separated and extracted four times with CH2Cl2 (25 mL). The combined organic layers were dried with MgSO4, concentrated under reduced pressure, and purified by silica gel column chromatography with (CH3(CH2)4CH3) / CH2Cl2 (5:95) as the eluent to obtain compound 1 (i.e., benzo[1,2] b:3,4 b′:5,6 b″]trifuran, a white solid, was reacted to produce a single product, which appeared as a single main spot on thin-layer chromatography (TLC). The product mass was 53.7 mg, the amount of substance was 0.271 mmol, and the yield was 54%.

[0059] 1 HNMR spectrum and 13 CNMR spectroscopy confirmed that compound 1 is benzo[1,2] b:3,4 b′:5,6 b″] Trifuran. 1 HNMR spectrum and 13 The CNMR spectrum data are as follows: 1 HNMR(CDCl3,500MHz): δ7.14(3H,d,J=2.5Hz),7.72(3H,d,J=2.0Hz)ppm; 13 C NMR (CDCl3, 125 MHz): δ146.3, 130.1, 120.5, 105.8.

[0060] Step S4: Compound 6 and compound 7 undergo a condensation reaction to obtain compound A2; ; To a mixture of compound 6 (i.e., 5,5′,5″-(benzo[1,2-b:3,4-b′:5,6-b″]trifuran-2,5,8-trimethylene)tris(3-(2-ethylhexyl)thiophene-2-carboxaldehyde) (0.046 mmol), compound 7 (i.e., 5,6-dichloro-3-(dicyanomethylene)indone) (0.46 mmol), and pyridine (1.5 mL), 15 mL of chloroform was added. The resulting mixture was refluxed for 2 h, concentrated after reflux, and purified by silica gel column chromatography using (CH3(CH2)4CH3) / CH2Cl2 (5:95 v / v) as eluent to give compound A2 (i.e., 2,2′,2″). ((2Z,2′Z,2″Z)-((benzo[1,2) b:3,4 b′:5,6 b″] Trifuran 2,5,8 Sanya Jisan (3) (2 Ethylhexylthiophene 5,2 Dimethylene subunit)) Tri(methylene subunit)) Tri(5,6 dichloro 3 oxygen 2,3 Dihydrogen 1 Indene 2,1 Di(trimalonidonitrile) is a dark green solid with a yield of 67%.

[0061] 1 HNMR spectrum and 13CNMR spectroscopy confirmed that compound A2 is a 2,2′,2″ shape. ((2Z,2′Z,2″Z)-((benzo[1,2) b:3,4 b′:5,6 b″] Trifuran 2,5,8 Sanya Jisan (3) (2 Ethylhexylthiophene 5,2 Dimethylene subunit)) Tri(methylene subunit)) Tri(5,6 dichloro 3 oxygen 2,3 Dihydrogen 1 Indene 2,1 Di-subunit)trimalonitrile. 1 HNMR spectrum and 13 The CNMR spectrum data are as follows: 1 HNMR(CDCl3,400MHz)δ(ppm):7.48(3H,s),7.19(3H,s),7.08(3H,s),6.80(3H,s),2.42(6H,m),1.68(3H,m),1.28(24H,m),0.89(18H,m); 13 C NMR (CDCl3, 125 MHz): δ190.6, 177.1, 157.0, 156.8, 152.3, 144.5, 142.1, 140.2, 135.1, 134.5, 134.4,129.1, 127.1, 119.9, 119.2, 116.3, 115.2, 115.7, 65.3, 41.4, 38.8, 32.1,31.9, 30.1, 29.2, 23.6, 15.9.

[0062] In summary, the non-fused-ring electron acceptor material and its preparation method provided in this application achieve conformational locking without alkoxy substitution by utilizing the oxygen heteroatom effect. While maintaining molecular planarity, it stably maintains a low HOMO energy level, thereby significantly improving compatibility with various donor materials. Furthermore, its preparation method features a simple synthetic route, controllable steps, mild conditions, and a single, high-purity product, making it suitable for large-scale preparation.

[0063] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A non-fused-ring electron acceptor material, characterized in that, The structural formula of the non-fused-ring electron acceptor material is shown in general formula I; wherein, the core group includes a benzotrifuran unit, the terminal group includes a halogen-substituted 3-(dicyanomethylene)inden-1-one unit, and the π-bridge between the terminal group and the core group includes an alkyl-substituted five-membered heterocyclic unit. (I)； In Formula I, X1 and X2 are each independently selected from fluorine, chlorine, or bromine; Y is selected from oxygen, sulfur, or selenium; and R is selected from C2~C2. 400 Straight-chain or branched alkyl groups.

2. The non-fused-ring electron acceptor material according to claim 1, characterized in that, R is selected from C2~C 50 Straight-chain or branched alkyl groups.

3. The non-fused-ring electron acceptor material according to claim 1, characterized in that, The non-fused-ring electron acceptor material is selected from compounds shown in formula A1 or A2; or .

4. A method for preparing a non-fused-ring electron acceptor material, characterized in that, Includes the following steps: S1. Compound 1 and compound 2 are subjected to a tin-reaction to obtain compound 3; ； S2. Compound 3 and compound 4 are subjected to a Stille coupling reaction to obtain compound 5; ； S3. Compound 5 is subjected to an aldehyde substitution reaction to obtain compound 6; ； S4. Compound 6 and compound 7 are subjected to a condensation reaction to obtain a compound of general formula I; ； Among them, X1 and X2 are each independently selected from fluorine, chlorine, or bromine; Y is selected from oxygen, sulfur, or selenium; and R is selected from C2~C. 400 Straight-chain or branched alkyl groups.

5. The method for preparing the non-fused-ring electron acceptor material according to claim 4, characterized in that, Before S1, the process further includes: S0, performing a nucleophilic addition reaction on compound a1 to obtain compound 1; 。 6. The method for preparing the non-fused-ring electron acceptor material according to claim 4, characterized in that, S1 includes: Compound 1 was dissolved in tetrahydrofuran solution, and a hexane solution of n-butyllithium was added dropwise at -10℃ to 5℃. The mixture was stirred at 15℃ to 30℃ for 0.5h to 3h, and then the system was cooled to -90℃ to -60℃. Compound 2 was added, and the reaction was carried out at -10℃ to 5℃ for 1h to 5h. After the reaction was completed, water was added to quench the reaction, and the mixture was purified by extraction and methanol precipitation to obtain compound 3. And / or, the molar ratio of compound 1 to compound 2 is 1:(3~6).

7. The method for preparing the non-fused-ring electron acceptor material according to claim 4, characterized in that, The S2 includes: Under nitrogen protection, toluene was added to compound 3, compound 4, Pd2(dba)3 and P-(o-tolyl)3, and the mixture was refluxed at 60℃~90℃ for 12h~18h. After the reaction was completed, water was added to quench the reaction, and compound 5 was obtained by extraction and silica gel column chromatography. And / or, the molar ratio of compound 3 to compound 4 is 1:(4~10); And / or, the molar ratio of compound 3, Pd2(dba)3 to P-(o-tolyl)3 is 1:(0.01~0.1):(0.1~0.5).

8. The method for preparing the non-fused-ring electron acceptor material according to claim 4, characterized in that, The S3 includes: Phosphorus oxychloride was dissolved in anhydrous N,N-dimethylformamide at -10℃ to 0℃, and stirred for 05h to 2h to obtain an aldehyde oxidizing agent. Compound 5 was dissolved in 1,2-dichloroethane solution, and the aldehyde oxidizing agent was added dropwise to the 1,2-dichloroethane solution of compound 5 at -10℃ to 0℃. After stirring for 20min to 50min, the system was heated to 60℃ to 90℃ and reacted for 12h to 18h. After the reaction was completed, sodium hydroxide solution was added to quench the reaction, and compound 6 was obtained by extraction and silica gel column chromatography purification.

9. The method for preparing the non-fused-ring electron acceptor material according to claim 4, characterized in that, The S4 includes: Chloroform was added to compound 6, compound 7 and pyridine, and the mixture was refluxed at 60℃~90℃ for 1h~3h. After the reaction was completed, the mixture was concentrated and purified by silica gel column chromatography to obtain compound of general formula I. And / or, the molar ratio of compound 6 to compound 7 is 1:(8~15).

10. The method for preparing the non-fused-ring electron acceptor material according to claim 5, characterized in that, The nucleophilic addition reaction of compound a1 to obtain compound 1 includes: The compound a1, cesium hydroxide monohydrate, and water were added to N,N-dimethylacetamide and reacted at 160℃~190℃ for 1h~3h. The system was then cooled to 20℃~30℃. After the reaction was completed, water was added to quench the reaction. The compound 1 was obtained by extraction and silica gel column chromatography.

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