CN109516985B - A kind of 1,3-bis(2-pyridyl)benzene acceptor unit and organic semiconductor material and application - Google Patents

Abstract

The invention discloses a 1,3-bis(2-pyridyl)benzene acceptor unit and an organic semiconductor material and application of indodipyridinedione. Taking 1,3-bis(2-pyridyl)benzene as the basic skeleton, introducing an electron-withdrawing group at the 6' position of the pyridine ring through Friedel-Crafts reaction, and using the intramolecular cyclization reaction to construct the dipyridine dipyridine The ketone novel electron acceptor framework further uses the indigo dipyridinedione framework unit as the electron acceptor, and constructs a donor-acceptor-donor organic semiconductor material through a coupling reaction, and the organic semiconductor material has excellent electrical properties. luminescence properties.

Description

A 1,3-bis(2-pyridyl)benzene acceptor unit and indadodipyridinedione have Organic Semiconductor Materials and Applications

technical field

The present invention relates to a novel organic semiconductor material, in particular to a 1,3-bis(2-pyridyl)benzene acceptor unit, and the use of 1,3-bis(2-pyridyl)benzene acceptor unit and organic donor unit The invention relates to an organic semiconductor material of indigo bipyridinedione constructed by a body unit, and also relates to the application of the organic semiconductor material of indigo bipyridinedione in a light-emitting device, which belongs to the technical field of organic electronic materials.

Background technique

1,3-Bis(2-pyridyl)benzene is known as "chelating ligand" due to its good conjugated structure, unique metal chelation, and easy molecular modification. It is widely used in inorganic/organic in metal complexes. The 1,3-bis(2-pyridyl)benzene unit possesses an N,C,N tri-coordinate skeleton, where N is a neutral donor unit and C represents an anionic aromatic ring C atom. In the past few decades, a large number of organometallic complexes based on 1,3-bis(2-pyridyl)benzene chelating ligands, such as metal platinum, iridium, palladium, ruthenium, etc., have been developed as luminescent materials, dye-sensitive Chemical batteries and catalysts, etc. It is worth noting that the structural modification of N,C,N chelating ligands has a great influence on the properties of their metal complexes. At present, the means for structural modification of 1,3-bis(2-pyridyl)benzene skeleton can be roughly divided into the following two types: 1. At positions 4, 5, and 6 of the benzene ring or at the 3', 4 position of the pyridine ring. ',5' to introduce electron donor or electron acceptor units (such as compound 1 in Fig. 1), but this method can only adjust the highest occupied orbital (HOMO) or lowest empty orbital (LUMO) of the material, The spatial structure of the material cannot be effectively regulated, resulting in a strong intermolecular interaction of the material; 2. Introducing an aromatic ring structure on the pyridine ring (such as compound 2 in Figure 1), this is only a simple introduction of a fused ring structure, did not effectively increase the degree of conjugation of 1,3-bis(2-pyridyl)benzene.

SUMMARY OF THE INVENTION

In view of the defects existing in the prior art, the object of the present invention is to provide a method by introducing an electron withdrawing group at the 6' position of the pyridine ring of the 1,3-bis(2-pyridyl)benzene framework or utilizing an intramolecular cyclization reaction Constructed a novel indadodipyridinedione acceptor unit, which is more planar and larger than the existing 1,3-bis(2-pyridyl)benzene backbone acceptor unit Conjugation and stronger electron acceptor properties.

Another object of the present invention is to provide a series of 1,3-bis(2-pyridyl)benzene acceptor units with excellent luminescence properties indadodipyridinedione donor-acceptor-donor type organic semiconductor materials.

The third object of the present invention is to provide this kind of donor-acceptor-donor type materials based on 1,3-bis(2-pyridyl)benzene derivatives for application as organic electroluminescent diode light-emitting materials, showing excellent performance electroluminescence properties.

In order to achieve the above technical purpose, the present invention provides a 1,3-bis(2-pyridyl)benzene electron acceptor unit, which has the structure of formula 1, formula 2 or formula 3:

in,

R is a halogen substituent;

R ₁ is an oxygen atom, a sulfur atom or a selenium atom;

R ₂ is a hydrogen atom or a halogen substituent.

In the preferred 1,3-bis(2-pyridyl)benzene electron acceptor unit, R is a chlorine substituent, R1 is _an oxygen atom, and R2 is a _hydrogen atom.

The present invention also provides a donor-acceptor-donor organic semiconductor material based on a 1,3-bis(2-pyridyl)benzene electron acceptor unit of indodipyridinedione, which has formula 4 , formula 5, formula 6, formula 7 or formula 8 structure:

in,

R ₁ is an oxygen atom, a sulfur atom or a selenium atom;

R ₃ is a donor unit.

In a preferred donor-acceptor-donor organic semiconductor material based on 1,3-bis(2-pyridyl)benzene electron acceptor units, R3 is one of the following structures:

The present invention also provides an application of a donor-acceptor-donor organic semiconductor material based on the 1,3-bis(2-pyridyl)benzene electron acceptor unit of indodipyridinedione, which serves as a Application of light-emitting layer materials for organic electroluminescent diodes.

The present invention is based on 1,3-bis(2-pyridyl)benzene skeleton, modifies an electron withdrawing group on the 6' position of the pyridine ring; Ketone derivatives, indigo bipyridinedione derivatives can be coupled with existing common donor units to obtain a series of donor-acceptor-donor organic semiconductor materials of indigo bipyridinedione .

In the present invention, an electron withdrawing group is introduced into the 6' position of the pyridine ring through the Friedel-Crafts reaction. This method can effectively regulate the spatial structure of the molecule, thereby regulating the intermolecular interaction. At the same time, in order to further increase the 1,3-bis(2- The degree of conjugation of pyridyl) benzene enhances its electron-withdrawing performance, and the present invention constructs a rigid skeleton of indadodipyridinedione through intramolecular cyclization reaction. Compared with the existing 1,3-bis(2-pyridyl)benzene skeletons, the rigid skeletons of inda-dipyridinedione exhibit obvious advantages, mainly in terms of better conjugation degree and electron-withdrawing ability . Compared with the prior art, the rigid skeleton of the indadodipyridinedione of the present invention has good optoelectronic properties, and is a class of organic semiconductor materials with commercialization prospects.

Relative to the prior art, the beneficial effects brought by the technical solution of the present invention are:

In the present invention, an electron withdrawing group is introduced into the 6th position of the pyridine ring in the 1,3-bis(2-pyridyl) benzene skeleton for the first time; meanwhile, an intramolecular cyclization reaction is used to construct the indadodipyridinedione for the first time. Molecular Skeleton.

Compared with the reported 1,3-bis(2-pyridyl)benzene molecular skeleton, the indabidinedione molecular skeleton of the present invention has better planarity and conjugation degree, stronger electron acceptor The host properties are beneficial to the construction of donor-acceptor-donor organic semiconductor materials, and the types of acceptor units of organic semiconductor materials are expanded.

In the present invention, different donor units are further introduced into the skeleton of indadodipyridinedione, and a series of organic semiconductor materials with novel structures are constructed.

Description of drawings

[Fig. 1] shows the structure modification method of 1,3-bis(2-pyridyl)benzene derivatives in the prior art and the technical solution of the present invention.

[Fig. 2] is the single crystal derivative structure of compound 9 prepared in Example 1 of the present invention.

[Fig. 3] is the single crystal derivative structure of compound 18 prepared in Example 2 of the present invention.

[Fig. 4] is the UV-Vis absorption spectrum of compound 9 and compound 10 prepared in Example 1 of the present invention in dichloromethane solution.

[Fig. 5] is the UV-Vis absorption spectrum of compound 18 prepared in Example 2 of the present invention in dichloromethane solution.

[Fig. 6] is the photoluminescence spectrum of compound 9 and compound 10 prepared in Example 1 of the present invention in dichloromethane solution.

[Fig. 7] is the photoluminescence spectrum of compound 18 prepared in Example 2 of the present invention in dichloromethane solution.

Detailed ways

The following specific embodiments are intended to further illustrate the present invention, but these specific embodiments do not limit the protection scope of the present invention in any way.

Example 1

Synthesis of compound 5-11: Reaction conditions: a) MeOH, room temperature, 2h, b) 1,3-benzenediboronic acid, Pd(dppf)Cl ₂ , K ₂ CO ₃ , THF/H ₂ O, 85°C, 24h , c)NaOH aq., ethanol, 80℃, 12h, d) AlCl ₃ , benzene, 135℃, 24h.

Synthesis of compound 6

In a 250ml single-necked bottle, add 2-bromonicotinic acid (5.0g, 24.8mmol), dichloromethane (100ml) to dissolve and 3 drops of DMF, oxalyl chloride (10mL) was added dropwise at 0°C, and the mixture was stirred at room temperature for 2h. The solvent was removed by rotary evaporation under reduced pressure, anhydrous methanol was added dropwise at 0°C, and after stirring at room temperature for 2 hours, the methanol was removed under reduced pressure, the crude product was dissolved in dichloromethane, washed with water, and the organic phase was dried with anhydrous magnesium sulfate, filtered, and reduced The solvent was spun off and dried to give a yellow liquid (3.8 g, 71%). ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.51 (dd, J=4.8, 1.6 Hz, 1H), 8.17 (dd, J=8.0, 1.6 Hz, 1H), 7.34-7.31 (m, 1H), 3.95 ( s, 3H).

Synthesis of compound 7

In a 100mL three-necked flask, 1,3-phenylenediboronic acid (0.66g, 4mmol), compound 6 (1.8g, 8.4mmol), potassium carbonate (1.1g, 7.97mmol), 1,1'-bis-di Phenylphosphinoferrocene palladium dichloride (0.146 g, 0.2 mmol) and tetrahydrofuran/water (20 mL/4 mL), the mixture was reacted at 70° C. for 24 h under nitrogen. After the reaction solution was cooled to room temperature, the solvent was removed under reduced pressure, and the residue was transferred to a separatory funnel with dichloromethane, washed with water (3×100 mL), the organic phase was dried with anhydrous magnesium sulfate, filtered, and the solvent was removed under reduced pressure. The product was separated by column chromatography using petroleum ether/ethyl acetate (V/V=5:1) as the eluent to obtain a colorless thick substance (1.0 g, 74%). ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.78 (dd, J=4.8, 1.6 Hz, 2H), 8.11 (dd, J=8.0, 2.0 Hz, 2H), 7.79 (t, J=1.2 Hz, 1H) , 7.64-7.57(m, 2H), 7,52-7.48(m, 1H), 7.36-7.33(m, 2H), 3.71(s, 6H).

Synthesis of Compound 8

Compound 7 (2.6 g, 7.47 mmol), sodium hydroxide (1.55 g, 38.9 mmol), ethanol (60 mL) and distilled water (12 mL) were added to a 100 mL single-neck flask, and the mixture was refluxed at 80° C. overnight. The ethanol was removed under reduced pressure, diluted hydrochloric acid was added dropwise to the residue until pH=2, a large amount of ethanol was added, the filtrate was collected by filtration, the solvent was removed under reduced pressure, and dried to obtain a white solid (2.2 g, 90%). ¹ H NMR (400MHz, DMSO) δ 8.77 (dd, J=4.8, 1.6Hz, 2H), 8.12 (dd, J=7.6, 1.6Hz, 2H), 7.85 (t, J=1.6Hz, 1H), 7.64-7.61 (m, 2H), 7.54-7.49 (m, 3H).

Synthesis of Compound 9 and Compound 10

Compound 8 (1.0 g, 3.13 mmol), AlCl ₃ (3.74 g, 28.1 mmol) and benzene were added to a 100 mL single-neck flask, and the mixture was stirred under reflux for 24 h under N ₂ . After the reaction was cooled to room temperature, 10 mL of saturated sodium bicarbonate was added for quenching, the reaction residue was evaporated to remove the solvent under reduced pressure, and the crude product was separated by column chromatography using petroleum ether/ethyl acetate (V/V=3:2) as the eluent. Compound 9 (350 mg, 22%) and compound 10 (170 mg, 10%) were obtained as white solids. Compound 9: ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.81 (dd, J=4.8, 1.6 Hz, 2H), 7.91 (t, J=2.0 Hz, 1H), 7.80 (dd, J=7.6, 1.6 Hz) , 2H), 7.56-7.53 (m, 4H), 7.37 (ddd, J=12.4, 7.6, 4.8Hz, 4H), 7.26-7.23 (m, 4H), 7.09 (t, J=7.6Hz, 1H). Compound 10: ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.83 (dd, J=18.4, 4.0 Hz, 2H), 7.96 (dd, 7.6 0.8 Hz, 1H), 7.81-7.76 (m, 2H), 7.56- 7.54(m,2H),7.41-7.36(m,4H),7.30-7.12(m,6H),7.08-7.04(m,1H).

Example 2

Synthesis of compounds 12-16: Reaction conditions: a) Pd(PPh ₃ ) ₄ , 2-pyridineboronic acid, b) PCC, BuOH, H ₂ O; c) n-BuLi, THF.

Synthesis of Compound 13

In a 100mL three-necked flask, 2-pyridineboronic acid (0.05mol), 1,5-dibromo-2,4-dimethylbenzene (5.3g, 0.02mol), Pd(PPh ₃ ) ₄ (0.28g, 0.4 mmol) and toluene, the mixture was reacted at 116 °C for 24 h under nitrogen. After the reaction solution was cooled to room temperature, washed sequentially with water (50 mL) and sodium bicarbonate solution (10%, 150 mL). The organic phase was dried with magnesium sulfate, and then the solvent was evaporated under reduced pressure. The crude product was separated by column chromatography using n-hexane/dichloromethane (V/V=8:1) as the eluent to obtain an off-white solid (3.6 g, 69%) . ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.70 (d, J=4.9, 2H), 7.73 (td, J=7.74, 1.8 Hz, 2H), 7.49 (s, 1H), 7.45 (d, J=8 ,2H),7.25-7.22(m,3H),2.42(s,6H).

Synthesis of compound 14

In a 250mL three-necked flask, compound 13 (1.6g, 6.15mmol), sodium hydroxide (0.49g, 12.3mmol) and tert-butanol/water (1:1) (100mL) were added successively, and the mixture was heated to 100° C. PCC (9.7 g) was added in portions and stirred for 4 h. After the reaction, it was filtered while hot, the filtrate was adjusted to pH=5 with 1N hydrochloric acid, filtered with suction, and the filter cake was washed with water and dried to obtain a white solid (1.4g, 72%). ¹ H NMR (300MHz, d-DMSO) δ13.00 (bs, 2H), 8.63(d, J=6Hz, 2H), 8.01(s, 2H), 7.90(dd, J=9Hz, 3Hz, 1H), 7.78(s, 1H), 7.74(d, J= 9Hz, 1H), 7.43-7.39 (dd, J=6Hz, 3Hz, 2H).

Synthesis of compound 15

Compound 14 (0.16g, 0.50mmol) and tetrahydrofuran (6mL) were added to a 25mL three-necked flask, n-butyllithium (2M, 1.3mL, 2.6mmol) was added at 0°C, and the mixture was reacted at room temperature for 2h, and then 2mL of water was added Quench the reaction. The reaction solution was extracted with dichloromethane (3×20 mL), the organic phase was dried over magnesium sulfate, the solvent was distilled under reduced pressure, and the residue was a column layer with dichloromethane/ethyl acetate (V/V=1:1) as the eluent A brown solid (63 mg, 44%) was isolated by precipitation. ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.75 (d, J=4.3, 2H), 8.44 (s, 1H), 8.07 (s, 1H), 7.98 (d, J=7.4, 2H), 7.34-7.40 (m, 2H).

Example 3

Synthesis of compounds 18 and 19. Reaction conditions: a) Pd(PPh ₃ ) ₄ , THF, K ₂ CO ₃ , 80℃, 8h; b) Pd(PPh ₃ ) ₄ , toluene, ethanol, K ₂ CO ₃ , 80℃, 16h.

Synthesis of compound 18

In a 50 mL three-necked flask, compound 17 (0.5 g, 1.14 mmol), diphenylamine (0.5 g, 3 mmol), Pd(PPh ₃ ) ₄ (0.05 eq), 2M K ₂ CO ₃ solution (10 mL) and tetrahydrofuran (26 mL) were added ), after the mixture was refluxed for 8 h, water was added to quench the reaction. The reaction solution was extracted with dichloromethane (3×20 mL), the organic phase was dried over magnesium sulfate, the solvent was distilled under reduced pressure, and the residue was subjected to column chromatography using petroleum ether/ethyl acetate (V/V=1:1) as the eluent. A white solid (0.5 g, 72%) was isolated. ¹ H NMR (400MHz, CDCl ₃ ) δ 9.10(s, 1H), 8.07(s, 1H), 7.96(s, 1H), 7.52(d, J=7.3, 2H), 8.44(s, 1H), 7.24-7.28 (m, 8H), 7.08-7.00 (m, 12H).

Synthesis of compound 19

In a 50mL three-necked flask was added compound 19 (0.5g, 1.14mmol), diphenylamine (0.5g, 3mmol), Pd(PPh ₃ ) ₄ (0.05eq), 2M K ₂ CO ₃ solution (10mL), toluene (15mL) ) and ethanol (15 mL). After the mixture was reacted at room temperature for 16 h, 2 mL of water was added to quench the reaction. The reaction solution was extracted with dichloromethane (3×20 mL), the organic phase was dried over magnesium sulfate, the solvent was distilled under reduced pressure, and the residue was a column layer with dichloromethane/ethyl acetate (V/V=1:1) as the eluent A white solid (0.58 g, 83%) was isolated by precipitation. ¹ H NMR (400 MHz, CDCl ₃ ) δ 9.23 (s, 2H), 7.96 (s, 2H), 7.52 (s, 2H), 7.24-7.28 (m, 8H), 7.08-7.00 (m, 12H).

Example 4

UV-Vis absorption spectrum test of Compound 9 in Example 1, Compound 10 and Compound 18 in Example 2.

Compound 9, compound 10 and compound 18 were respectively dissolved in dichloromethane solution to prepare 10 ^-5 M solution, and the UV-visible absorption spectrum of the solution was tested. It can be seen from the figure that the UV-Vis absorption spectra of compound 9 and compound 10 in dichloromethane solution are roughly the same, and the maximum absorption peak is 262 nm, which is mainly due to the π-π electron transition; compared with compound 9 and compound 10, compound 18 It exhibits distinct absorption spectra in dichloromethane solution. It has absorption peaks at 264nm, 280nm and 340nm, respectively. Among them, the absorption at 264 nm originates from the π-π electronic transition, and the absorption at 280 nm and 340 nm is attributed to the n-π ^* electronic transition.

Example 5

Steady-state fluorescence spectroscopy test of Compound 9 in Example 1, Compound 10 and Compound 18 in Example 2.

Compound 9, compound 10 and compound 18 were respectively dissolved in dichloromethane solution to prepare 10 ^-5 M solution, and the photoluminescence spectrum of the solution was tested. 6 and 7 are photoluminescence spectra of compound 9, compound 10 and compound 18 in solution.

It can be seen from the figure that under light excitation, compound 9 and compound 10 show similar emission spectra in dichloromethane solution, and the maximum emission peak is 365 nm; the emission spectrum of compound 18 in dichloromethane solution shows a larger red color. The maximum emission peak is 518 nm, which indicates that compound 18 has a greater degree of conjugation than compound 9 and compound 10.

Although the present invention has been described in connection with the preferred embodiments, the present invention is not limited to the above-described embodiments, and it should be understood that the scope of the invention is outlined in the appended claims. Under the guidance of the inventive concept, those skilled in the art should realize that certain changes made to the various embodiments of the present invention will be covered by the spirit and scope of the claims of the present invention.

Example 6

Electroluminescent device performance test of compound 18 in Example 2.

Compound 18 was dissolved in dichlorobenzene solution to prepare a 10 mg/mL solution, compound 18 was used as a dopant in the light-emitting layer, PVK was used as a hole transport layer, mCP was used as host material, and Liq was used as cathode material to prepare solution-processed organic electronics. luminescent device. The device results show that the electroluminescent device based on compound 18 has a maximum external quantum efficiency of 19.2%, a maximum luminescence brightness of 12000cd/m ² , and a very small roll-off of efficiency, which has a very good commercialization prospect.

Claims (2)

1. a donor-acceptor-donor type organic semiconductor material based on 1,3-bis (2-pyridyl) benzene electron acceptor unit inducted into bispyridinedione, it is characterized in that: has formula 6 Or formula 7 structure:

in, R ₁ is an oxygen atom, a sulfur atom or a selenium atom; R ₃ is one of the following structures:

2. the application of a kind of donor-acceptor-donor organic semiconductor material based on 1,3-bis (2-pyridyl) benzene electron acceptor unit as claimed in claim 1. , which is characterized in that it is used as a light-emitting layer material for organic electroluminescent diodes.

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