CN104402937A - Green phosphorescence pyrimidine iridium complex and preparation method thereof - Google Patents

Abstract

The invention provides a green phosphorescent pyrimidine iridium complex and a preparation method thereof, belonging to the technical field of electrophosphorescent materials. The preparation method comprises the preparation of the ring metal ligand, the preparation of the chlorine-bridged iridium complex, and the preparation steps of the iridium complex, and finally the structural formula is green phosphorescent pyrimidine iridium complex. The CH ₂ Cl ₂ solution of the iridium complex provided by the present invention can emit green phosphorescence under the excitation light of 400nm, CIEx, y chromaticity coordinates are (0.26, 0.60), the preparation method of the present invention has simple preparation process, and the raw materials are easy to obtain .

Description

Green phosphorescent pyrimidine iridium complex and preparation method thereof

technical field

The invention belongs to the technical field of electrophosphorescent materials, and relates to a green phosphorescent pyrimidine iridium complex and a preparation method thereof.

Background technique

In recent years, electrophosphorescent materials have become a research hotspot because of their good luminescent properties and theoretically 100% internal quantum efficiency.

The electrophosphorescent materials currently studied are mainly organic heavy metal complexes such as osmium, iridium, platinum, and ruthenium. Metal iridium complexes have relatively short triplet lifetimes and higher luminous efficiency, and can emit strong phosphorescence at room temperature. And the emission wavelength can be adjusted through the adjustment of the ligand structure so that the color of the electroluminescent device covers the entire visible light region. It is the most studied phosphorescent material.

The iridium complexes of pyrimidine and its derivatives have relatively high efficiency and long device life as electrophosphorescent materials, but there are relatively few phosphorescent materials of pyrimidine iridium complexes reported in the literature.

Contents of the invention

The purpose of the invention is to provide a green phosphorescent pyrimidine iridium complex with a new structure, which can be used as an electrophosphorescent material.

Another object of the present invention is to provide an easy-to-implement preparation method of the green phosphorescent pyrimidine iridium complex.

The technical scheme of the present invention is: a green phosphorescent pyrimidine iridium complex having the following structural formula:

The maximum photoluminescent emission peak of the CH ₂ Cl ₂ solution of the green phosphorescent pyrimidine iridium complex is at 512 nm, and its chromaticity coordinates are CIE (0.26, 0.60), indicating that the phosphorescent iridium complex is a green phosphorescent material.

Another technical scheme of the present invention is:

A preparation method of green phosphorescent pyrimidine iridium complex, comprising the following steps:

A. Preparation of ring metal ligand: 2-chloro-4,6-dimethylpyrimidine and phenylboronic acid are added to the mixed solution of triphenylphosphine, ethylene glycol dimethyl ether and saturated potassium carbonate solution, and palladium acetate and heated to reflux under the protection of nitrogen for 10-24 hours, cooled and separated to obtain the first organic phase, the water phase was extracted with ethyl acetate, and separated again to obtain the second organic phase; the first organic phase was combined And the second organic phase, join in the silica gel column, take dichloromethane as eluent elution, obtain eluent, distill eluent, obtain ring metal ligand 4,6-dimethyl-2-phenyl Pyrimidine, whose structural formula is: named MPPM;

B. Preparation of chlorine-bridged iridium complex: add IrCl ₃ 3H ₂ O, ring metal ligand, ethylene glycol monoethyl ether and water into the reaction flask, and reflux at 80°C-120°C under the protection of nitrogen After 10-24 hours, cool and filter to obtain a precipitate, which is washed with water, ethanol, and acetone in turn, and dried to obtain a chlorine-bridged dimer, whose structural formula is: named as [(MPPM) ₂ IrCl] ₂ ;

C. Preparation of iridium complex: Add chlorine-bridged dimer and picolinic acid to 1,2-dichloroethane, react at 50-80°C for 12-24 hours under nitrogen protection, cool, filter the reactant, The filtrate was obtained, the filter residue was extracted with chloroform to obtain the extract, the filtrate and the extract were mixed, concentrated, and the mixed solvent of acetone and dichloromethane was used as the eluent for silica gel column chromatography to obtain the eluent, and the eluate was evaporated Obtain dark green powdery solid, i.e. iridium complex, its structural formula is: Named (MPPM) ₂ Ir(pic).

The overall reaction formula is as follows:

In the preparation method of the above-mentioned green phosphorescent pyrimidine iridium complex, in step A, the volume ratio of acetone and methylene chloride in the mixed solvent of acetone and methylene chloride is 1:10, and in step C, the chlorine bridge dimerization The molar ratio of body and picolinic acid is 1:2-10, and the volume ratio of acetone and dichloromethane in the mixed solvent of acetone and dichloromethane is 1:10.

Compared with the prior art, the present invention has the advantages of:

1. The CH ₂ Cl ₂ solution of the iridium complex provided by the present invention can emit green phosphorescence under the excitation light of 400nm, and the CIEx, y chromaticity coordinates are (0.26, 0.60);

2. The preparation method provided by the present invention has a simple preparation process and easy access to raw materials;

3. The organic electroluminescence device prepared by using the iridium complex provided by the invention as the guest material has good luminescence performance.

4. The iridium complex provided by the invention can be used as a luminescent material, a guest material and a doping material for making green electroluminescent devices.

Description of drawings

Fig. 1 is the ultraviolet _- visible absorption spectrogram of the green phosphorescent pyrimidine iridium complex provided by the present invention in _CH2Cl2 solution;

Fig. 2 is the emission spectrum (ex=400nm) of the green phosphorescent pyrimidine iridium complex in CH ₂ Cl ₂ solution provided by the present invention.

Detailed ways

Example 1

A green phosphorescent pyrimidine iridium complex is characterized in that it has the following structural formula:

As shown in Figure 1, the relatively strong absorption peak of the iridium complex (MPPM) ₂ Ir(pic) at 240-380 nm can be attributed to the (π→π*) transition within the ligand. The absorption peak at 440nm should be metal-to-ligand charge transfer transition absorption (MLCT).

As shown in Figure 2, the maximum photoluminescent emission peak of the green phosphorescent pyrimidine iridium complex is at 512nm, and its chromaticity coordinates are CIE (0.26, 0.60), indicating that the phosphorescent iridium complex is a green phosphorescent material.

Example 2

A preparation method of green phosphorescent pyrimidine iridium complex, comprising the following steps:

A. Preparation of ring metal ligand: 2-chloro-4,6-dimethylpyrimidine and phenylboronic acid are added to the mixed solution of triphenylphosphine, ethylene glycol dimethyl ether and saturated potassium carbonate solution, and palladium acetate and heated to reflux under the protection of nitrogen for 10-24 hours, cooled and separated to obtain the first organic phase, the water phase was extracted with ethyl acetate, and separated again to obtain the second organic phase; the first organic phase was combined And the second organic phase, join in the silica gel column, take dichloromethane as eluent elution, obtain eluent, distill eluent, obtain ring metal ligand, its structural formula is:

B. Preparation of chlorine-bridged iridium complex: add IrCl ₃ 3H ₂ O, ring metal ligand, ethylene glycol monoethyl ether and water into the reaction flask, and reflux at 80°C-120°C under the protection of nitrogen After 10-24 hours, cool and filter to obtain a precipitate, which is washed with water, ethanol, and acetone in turn, and dried to obtain a chlorine-bridged dimer, whose structural formula is:

C. Preparation of iridium complex: Add chlorine-bridged dimer and picolinic acid to 1,2-dichloroethane, react at 50-80°C for 12-24 hours under nitrogen protection, cool, filter the reactant, The filtrate was obtained, the filter residue was extracted with chloroform to obtain the extract, the filtrate and the extract were mixed, concentrated, and the mixed solvent of acetone and dichloromethane was used as the eluent for silica gel column chromatography to obtain the eluent, and the eluate was evaporated Obtain dark green powdery solid, i.e. iridium complex, its structural formula is:

In the above preparation method, preferably, in step A, the volume ratio of acetone and dichloromethane in the mixed solvent of acetone and dichloromethane is 1:10, and in step C, the chlorine-bridged dimer and picolinic acid The molar ratio of the acetone and dichloromethane in the mixed solvent of acetone and dichloromethane is 1:10.

Example 3

In a 100ml reaction flask, add 3.5342g (25mmol) 2-chloro-4,6-dimethylpyrimidine, 3.6503g (30mmol) phenylboronic acid, 0.6911g (2.63mmol) triphenylphosphine, 25ml ethylene glycol Dimethyl ether, 34ml of saturated potassium carbonate solution (67.5mmol). Nitrogen was blown, and then 0.14 g (0.625 mmol) of palladium acetate was added, heated to reflux for 18 h, and cooled to room temperature. The organic phase of the product was separated, and the aqueous phase was extracted with ethyl acetate (60ml×4) to obtain an organic phase. The combined organic phases were washed with 80 ml of water and 80 ml of saturated brine. Dry over anhydrous magnesium sulfate, filter, concentrate the filtrate, carry out silica gel column chromatography with dichloromethane as eluent, obtain 1.9018g light yellow solid 4,6-dimethyl-2-phenylpyrimidine (MPPM), the yield 41%. ¹ HNMR (CDCl ₃ , 400MHz) δ: 8.43(t, 2H), 7.51(t, 4H), 6.92(m, 1H), 2.50(m, 6H)

Weigh 0.5277g of 4,6-dimethyl-2-phenylpyrimidine (MPPM), 0.4549g of IrCl ₃ ·3H ₂ O into a 100ml reaction flask, add 30ml of ethylene glycol monoethyl ether and 10ml of distilled water. Blow nitrogen, stir at room temperature for 1 h, then heat to reflux for 24 h, cool to room temperature, add water to precipitate, filter with suction, wash with water, ethanol, acetone, and dry in vacuo to obtain 0.3086 g of dark green solid [(MPPM) ₂ IrCl] ₂ , yield 36%.

Weigh 0.2392g (0.2mmol) [(MPPM) ₂ IrCl] ₂ and 0.0516g (0.4mmol) picolinic acid into a 50ml reaction flask, then add 15ml 1,2-dichloroethane, blow in nitrogen, and heat to reflux for 24h . Cool and filter to obtain the filtrate, extract the filter residue with chloroform to obtain the extract, mix the filtrate and extract, concentrate, and use acetone and dichloromethane mixed solvent (acetone:dichloromethane=1:10V/V) as eluent The reagent was subjected to silica gel column chromatography to obtain 0.1677 g of solid, yield 62%. ¹ HNMR (CDCl ₃ , 400MHz) δ: 7.82(t, 2H), 7.62(d, 1H), 7.53(m, 4H), 7.43(m, 2H), 7.24(m, 2H), 6.71(d, 2H ), 6.58(d, 1H), 2.71(d, 12H).

Example 4

The steps of the preparation method provided in this example and Example 2 are basically the same, the difference is that in step A, the molar ratio of 2-chloro-4,6-dimethylpyrimidine: phenylboronic acid: triphenylphosphine is 1 : 1: 1.2, the heating and reflux time was 15 hours; step B, the weight ratio of 4,6-dimethyl-2-phenylpyrimidine (MPPM) and IrCl was 1: ₁ , and refluxed at 95° C. for 12 hours; Step C, the molar ratio of [(MPPM) ₂ IrCl] ₂ to picolinic acid was 1:2.5, and the reaction was carried out at 55° C. for 14 hours under the protection of nitrogen.

Example 5

The steps of the preparation method provided in this example and Example 2 are basically the same, the difference is that in step A, the molar ratio of 2-chloro-4,6-dimethylpyrimidine: phenylboronic acid: triphenylphosphine is 1 : 1.05: 1.3, the heating and reflux time was 16 hours; Step B, 4,6-dimethyl-2-phenylpyrimidine (MPPM) and IrCl The weight ratio was 1: _1.2 , and refluxed at 75° C. for 14 hours; In step C, the molar ratio of [(MPPM) ₂ IrCl] ₂ to picolinic acid was 1:5, and the reaction was carried out at 70° C. for 14 hours under the protection of nitrogen.

Example 6

The steps of the preparation method provided in this example and Example 2 are basically the same, the difference is that in step A, the molar ratio of 2-chloro-4,6-dimethylpyrimidine: phenylboronic acid: triphenylphosphine is 1 : 1.1: 1.3, the heating and reflux time is 23 hours; step B, 4,6-dimethyl-2-phenylpyrimidine (MPPM) and IrCl The weight ratio is 1: _1.1 , reflux at 85 ° C for 17 hours in light; In Step C, the molar ratio of [(MPPM) ₂ IrCl] ₂ to picolinic acid was 1:3.5, and the reaction was carried out at 80° C. for 18 hours under the protection of nitrogen.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which the present invention belongs can make various modifications or supplements to the described specific embodiments or adopt similar methods to replace them, but they will not deviate from the spirit of the present invention or go beyond the definition of the appended claims range.

Claims (3)

1. a green phosphorescent pyrimidine complex of iridium, is characterized in that, has following structural formula:

2. a preparation method for green phosphorescent pyrimidine complex of iridium, is characterized in that, comprises the following steps:

The preparation of A, cyclic metal complexes: by chloro-for 2-4,6-dimethyl pyrimidine and phenyl-boron dihydroxide join in the mixing solutions of triphenylphosphine, glycol dimethyl ether and unsaturated carbonate potassium solution, add palladium and reflux 10-24 hour under nitrogen protection, cooling layering, separation obtains the first organic phase, aqueous phase is extracted with ethyl acetate, and secondary clearing again, be separated and obtain Second Organic Phase; Merge the first organic phase and Second Organic Phase, join in silicagel column, take methylene dichloride as eluent, obtain elutriant, distillation elutriant, obtain cyclic metal complexes, its structural formula is:

The preparation of B, chlorine bridging complex of iridium: by IrCl ₃3H ₂o, cyclic metal complexes and ethylene glycol monoethyl ether and water join in reaction flask; under nitrogen protection; at 80 DEG C of-120 DEG C of shadings backflow 10-24 hour; cold filtration; filtration is precipitated thing; throw out uses water, ethanol, washing with acetone successively, and obtain chlorine bridging dimer after drying, its structural formula is:

The preparation of C, complex of iridium: chlorine bridging dimer and pyridine carboxylic acid are joined in 1,2-ethylene dichloride, under nitrogen protection 50-80 DEG C of reaction 12-24 hour; cooling, filters reactant, obtains filtered liquid; filter residue chloroform extraction obtains extracting solution; hybrid filtering liquid and extracting solution, concentrated, carry out silica gel column chromatography using acetone and methylene dichloride mixed solvent as eluent; obtain elutriant; evaporation of eluate obtains blackish green pulverulent solids, is complex of iridium, and its structural formula is:

3. the preparation method of green phosphorescent pyrimidine complex of iridium according to claim 2, it is characterized in that, in step, in acetone and methylene dichloride mixed solvent, the volume ratio of acetone and methylene dichloride is 1: 10, in step C, the mol ratio of chlorine bridging dimer and pyridine carboxylic acid is 1: 2-10, and in acetone and methylene dichloride mixed solvent, the volume ratio of acetone and methylene dichloride is 1: 10.