CN1569910A - Polymer with main chain possessing biphenyl flumaronitrile structural unit, its preparation method and uses - Google Patents

Abstract

The invention relates to a polymer electroluminescent material containing diphenyl fumaronitrile structural units in the main chain and a manufacturing method thereof. This material is characterized in that its main chain contains diphenyl fumaronitrile structural units. The polymer has high thermal stability, is soluble in common organic solvents, and has good film-forming properties; it also has strong fluorescence and can be used in electroluminescent materials. This material is obtained by Suzuki coupling condensation of bis(4-halophenyl)fumaronitrile monomer and diaryl borate in the presence of organic palladium catalyst and inorganic base in organic solvent.

Description

Polymer containing diphenyl fumaronitrile structural unit on main chain, its preparation method and use

Technical Field

The invention relates to a novel polymer electroluminescent material containing diphenyl fumaronitrile structural units on a main chain and a manufacturing method thereof, in particular to the field of synthesis of information materials and functional polymers.

Background

The benzofumaronitrile derivatives are an important class of organic intermediates, mainly used for synthesizing macrocyclic phthalocyanine, as fluorescent synergist and the like (organic Chemistry, 2003, 42, 2683). In recent years, they have been used to synthesize some charge transport compounds because they contain cyano groups that strongly push electrons. The main use of these charge transport compounds is as a constituent material of Organic Light Emitting Diodes (OLEDs) (chem.commun., 2003, 2632). The OLED prepared by the compound has the advantages of low starting voltage and high luminous quantum efficiency, and has a good development prospect. The disadvantage is that, like most of small molecule organic photoelectric materials, due to the limitation of the manufacturing equipment, luminescent materials composed of small molecule compounds of the benzofumaronitrile class are difficult to obtain large-sized devices, and at the same time, they are easy to recrystallize due to the heat generation of the devices during long-term use, thereby causing the performance degradation of the devices. As such, the use of such small molecule materials is necessarily limited.

On the other hand, organic polymer electroluminescent materials have many incomparable advantages with small molecule electroluminescent materials, and are remarkably represented by large-size devices obtained by a simple spin-coating film-forming manner. In addition, most organic polymer light-emitting materials have higher glass transition temperature and excellent thermal stability, and the performance of devices is not reduced due to long-term use.

Disclosure of Invention

The invention takes the defects of the benzofumaronitrile micromolecule luminescent material as a starting point to be overcome, and the polymer with the main chain containing the benzofumaronitrile structural unit is synthesized, namely, the novel polymer electroluminescent material is provided. The material has good thermal stability and good processability, and can obtain large-size films.

The invention provides a novel polymer containing a benzofumaronitrile unit in a main chain, which has the following chemical structural formula:

wherein,

in the formula, R is C₁-C₂₀Is preferably C₄A C₁₂Alkyl group of (1). Ar (Ar)₁＝

The polymer preferably has n of 2 to 60, and more preferably n of 20 to 40. The polymer preferably has Mn of 5000 to 20000.

The polymer of the invention is obtained by the following scheme:

in an organic solvent containing inorganic base and in the presence of an organic palladium catalyst, the molecular formula is

Bis (4-halophenyl) fumaronitrile monomer and the following diarylboronic acid ester comonomers

And (3) reacting to obtain the product.

Formula (III) R, Ar₁As previously described.

Preferred reaction conditions are as follows: mixing the bis (4-halophenyl) fumaronitrile monomer and the diarylborate comonomer in the organic solvent containing the organic palladium catalyst under the protection of inert gas, stirring the mixture evenly, and then adding an inorganic alkaline aqueous solution. The mixture is heated to 60-150 deg.C (preferably 60-80 deg.C), and kept at this temperature for 72-100 hours. In the synthesis, bis (4-halophenyl) fumaronitrile monomer: the molar ratio of the diaryl borate comonomer is 1: 1-1.15, preferably 1: 1; the organic palladium catalyst may be palladium acetate, Pd (PPh)₃)₄，Pd₂(dba)₃And the like. Preferably Pd (PPh)₃)₄The amount of the compound is 3 to 20 mol%, preferably 3 to 5 mol% of the bis (4-halophenyl) fumaronitrile monomer.

The novel polymer is mainly used as a light-emitting layer of a light-emitting device.

The polymer is dissolved in common organic solvent, and when a corresponding luminescent device is prepared, a spin coating method is adopted. The polymer is dissolved in a certain organic solvent, the obtained solution is formed into a film on ITO (indium tin oxide) glass by a spin coater, and finally a metal cathode (aluminum or silver magnesium alloy) is evaporated on an organic film in vacuum. The solvent is THF, benzene, toluene, halogenated alkane or halogenated aromatic hydrocarbon. The concentration of the polymer organic solution is 0.1-1%

Table 1 shows the properties of a light emitting device comprising one of the polymers according to the invention.

TABLE 1 Properties of light-emitting device made of a polymer containing fumaronitrile in its main chain

[ note)]PVK is a polyvinyl carbazole,^*the driving voltage was 14V.

As can be seen from Table 1, the single-layer OLED device made of the polymer containing fumaronitrile units in the main chain has strong brightness and high external quantum efficiency.

Detailed Description

The following examples are helpful in understanding the present invention, but are not intended to limit the scope of the present invention.

For the sake of clarity, the structures of the polymers in the following examples and their corresponding reference numerals 1a, 1b, 1c, 1d and 1e are as follows.

Synthesis of example 11 a

To a 200 ml Schlenk tube were added 776mg of bis (4-bromophenyl) fumaronitrile (2.0mmol), 826mg of triphenylaminyl ethylene diboronate (2.0mmol) and 69mg of Pd (PPh)₃)₄(0.06 mmol). 100 ml of a mixture of toluene and THF (3: 1, V/V) were added to the mixture under nitrogen, and after stirring to homogeneity, 10 ml of 2M deaerated Na were added₂CO₃(20 mmol). The reaction mixture was heated to 80 ℃ and after vigorous stirring at this temperature for 72 hours, cooled to room temperature. After the aqueous layer was separated, the organic phase was washed with 5% by weight of an aqueous EDTA solution and deionized water, respectively, and anhydrous Na₂SO₄And (5) drying. The organic solvent was evaporated under negative pressure and the dark yellow residue was dissolved in about 10 ml of chloroform and poured into 2 l of methanol to give a dark yellow precipitate. The precipitate was placed in a soxhlet extractor and extracted with methanol for 48 hours to give 1a727mg in 77% yield. Number average molecular weight Mn of 9,200(GPC, CHCl)₃)；Mw/Mn＝1.88，IR(cm^-1)1600，2200；¹H NMR(CDCl₃)δ6.56-7.86(m，21H)。

Synthesis of example 21 b

A200 ml Schlenk tube was charged with 732mg of bis (4-bromophenyl) fumaronitrile (1.89mmol), 949mg of 2, 5-bis (dodecyloxy) -1, 4-benzenediboronic acid pinacol ester (1.89mmol) and 66mg of Pd (PPh)₃)₄(0.0571 mmol). 100 ml of a mixture of toluene and THF (3: 1, V/V) were added to the mixture under nitrogen, and after stirring to homogeneity, 9.5 ml of 2M air-removed Na were added₂CO₃(19 mmol). The reaction mixture was heated to 80 ℃ and after vigorous stirring at this temperature for 72 hours, cooled to room temperature. After the aqueous layer was separated, the organic phase was washed with 5% by weight of an aqueous EDTA solution and deionized water, respectively, and anhydrous Na₂SO₄And (5) drying. The organic solvent is evaporated under negative pressure and the dark yellow residue is dissolved in about 10 ml of chloroform and poured into 2 l of methanolA dark yellow precipitate was obtained. The precipitate was placed in a soxhlet extractor and extracted with methanol for 48 hours to give 1b800mg in 63% yield. Number average molecular weight Mn is 14,000(GPC, CHCl)₃)；Mw/Mn＝1.66，IR(cm-1)1602，2200；¹H NMR(CDCl₃)δ0.82(t，6H)，1.18(m，36H)，1.67(m，4H)，3.87(t，4H)，6.79-7.88(m，10H)。

Synthesis of example 31 c

To a 200 ml Schlenk tube were added 776mg of bis (4-bromophenyl) fumaronitrile (2.0mmol), 838mg of N-hexyl-2, 6-diboronic acid glycol ester carbazole (2.0mmol) and 69mg of Pd (PPh)₃)₄(0.06 mmol). 100 ml of a mixture of toluene and THF (3: 1, V/V) were added to the mixture under nitrogen, and after stirring to homogeneity, 10 ml of 2M deaerated Na were added₂CO₃(20 mmol). The reaction mixture was heated to 80 ℃ and after vigorous stirring at this temperature for 72 hours, cooled to room temperature. After the aqueous layer was separated, the organic phase was washed with 5% by weight of an aqueous EDTA solution and deionized water, respectively, and anhydrous Na₂SO₄And (5) drying. The organic solvent was evaporated under negative pressure and the dark yellow residue was dissolved in about 10 ml of chloroform and poured into 2 l of methanol to give a reddish yellow precipitate. The precipitate was placed in a soxhlet extractor and extracted with methanol for 48 hours to give 1c574mg in 60% yield. Number average molecular weight Mn of 6,800(GPC, CHCl)₃)；Mw/Mn＝1.99，IR(cm^-1)1580，2205；¹HNMR(CDCl₃)δ0.84(t，3H)，1.34(m，6H)，1.76(m，2H)，3.83(t，2H)，6.62-7.84(m，15H)。

Synthesis of example 41 d

Into a 200 ml Schlenk tube were added 388mg of bis (4-bromophenyl) fumaronitrile (1.0mmol), 821mg of 9, 9-bis (triphenylamino) -2, 7-diboronic acid glycolylfluorene (1.0mmol) and 35mg of Pd (PPh)₃)₄(0.036 mmol). 100 ml of a mixture of toluene and THF (3: 1, V/V) were added to the mixture under nitrogen, and after stirring to homogeneity, 5 ml of 2M deaerated Na were added₂CO₃(10mmol). The reaction mixture was heated to 80 ℃ and after vigorous stirring at this temperature for 72 hours, cooled to room temperature. Separating and removing a water layer; the organic phase was washed with 5% by weight aqueous EDTA and deionized water, respectively, and anhydrous Na₂SO₄And (5) drying. The organic solvent was evaporated under negative pressure and the dark yellow residue was dissolved in about 10 ml of chloroform and poured into 2 l of methanol to give a dark yellow precipitate. The precipitate was placed in a soxhlet extractor and extracted with methanol for 48 hours to give 1d703mg in 80% yield. Number average molecular weight Mn 8, 800(GPC, CHCl)₃)；Mw/Mn＝1.72，IR(cm^-1)1585，2200；¹H NMR(CDCl₃)δ6.36-7.85(m，42H)。

Synthesis of example 51 e

To a 200 ml Schlenk tube were added 776mg of bis (4-bromophenyl) fumaronitrile (2.0mmol), 672mg of 3-hexyl-2, 5-diboronic acid ethyleneglycolylthiophenol (2.0mmol) and 70mg of Pd (PPh)₃)₄(0.06 mmol). 100 ml of a mixture of toluene and THF (3: 1, V/V) were added to the mixture under nitrogen, and after stirring to homogeneity, 10 ml of 2M deaerated Na were added₂CO₃(20 mmol). The reaction mixture was heated to 80 ℃ and after vigorous stirring at this temperature for 72 hours, cooled to room temperature. After the aqueous layer was separated, the organic phase was washed with 5% by weight of an aqueous EDTA solution and deionized water, respectively, and anhydrous Na₂SO₄And (5) drying. The organic solvent was evaporated under negative pressure and the dark yellow residue was dissolved in about 10 ml of chloroform and poured into 2 l of methanol to give a brownish yellow precipitate. The precipitate was placed in a soxhlet extractor and extracted with methanol for 48 hours to give 1e510mg in 65% yield. Number average molecular weight Mn 7, 100(GPC, CHCl)₃)；Mw/Mn＝1.86，IR(cm^-1)1633，2200，2980.¹H NMR(CDCl₃)δ0.87(t，3H)，1.36(m，6H)，1.72(m，2H)，3.79(t，2H)，6.71(s，1H)，7.22-7.86(m，8H)。

EXAMPLE 6 device fabrication

The polymer obtained in the previous example was used as a light emitting layer, and PVK was used as a hole transporting layer, and the device was prepared by first coating the PVK on ITO glass (anode) by spin coating, then spin coating the polymer obtained in the previous example, and finally evaporating aluminum (cathode). The properties of a typical device are shown in table 1.

Claims (10)

1. A polymer electroluminescent material containing a fumaronitrile structure on a main chain is characterized in that the polymer has a chemical structural formula as shown in the following:

wherein Ar ═ is

In the formula, R is C₁-C₂₀Alkyl group of (1). Ar (Ar)₁＝

2. The polymer of claim 1, wherein n is 2 to 60.

3. The polymer according to claim 1, wherein R is C₄-C₁₂Alkyl group of (1).

4. The polymer according to claim 1, wherein the number average molecular weight Mn of the polymer is 5000 to 20000.

5. A process for the preparation of a polymer as claimed in claim 1, 2, 3 or 4, characterized in that it is prepared by:

in an organic solvent containing inorganic base and in the presence of an organic palladium catalyst, the molecular formula is

With an aromatic diboronate comonomer of the formula

And (3) reacting to obtain the product.

6. The method for preparing polymer according to claim 5, wherein the molar ratio of the bis (4-halophenyl) fumaronitrile monomer to the aromatic diboronate comonomer is 1: 1 to 1.5, and the reaction is carried out at 60 to 150 ℃ for 72 to 100 hours.

7. A process for the preparation of polymers as claimed in claim 5, wherein the reaction is carried out at from 60 to 80 ℃.

8. The method for preparing a polymer according to claim 5, wherein the organic solvent is tetrahydrofuran, benzene, toluene, ethylbenzene, or the like; the organic palladium catalyst may be palladium acetate, Pd (PPh)₃)₄，Pd₂(dba)₃Etc.; the inorganic base is potassium hydroxide, sodium hydroxide, cesium hydroxide, potassium carbonate, sodium carbonate, or cesium carbonate.

9. Process for the preparation of polymer according to claim 5, characterized in that the organic palladium catalyst may be Pd (PPh)₃)₄In an amount of 3 to 20 mol% (relative to the bis (4-halophenyl) fumaronitrile monomer); the inorganic alkali is 2M sodium carbonate aqueous solution; the organic solvent is a 3: 1 (volume ratio) mixture of toluene and THF.

10. Use of the polymer according to claim 1 as an electroluminescent material.