KR101610226B1 - Metal complex containing carbazoles connected Phenyl-pyridine, it's preparation method and it's applications - Google Patents

Abstract

The present invention relates to phenyl-pyridine-based metal complexes linked with a carbazole structure represented by formula (1). Exhibit high electroluminescence (EL) intensities at 700 to 750 nm and are therefore more suitable for use in organic light emitting diodes for sensors in the 700 to 750 nm region than reference metal complexes that do not include carbazole structures.

Formula 1

Emitting material, diode, OLED, sensor material, organic metal, dendrimer

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal complex containing a phenylpyridine structure connected to a carbazole structure,

The most widely used liquid crystal display (LCD) is a non-luminous display device, which consumes less power and is light in weight. However, the device driving system is complicated, and response time and congestion are not satisfactory. Therefore, research on an organic electroluminescence device, which has recently attracted attention as a next-generation flat panel display, has been actively conducted. The organic light emitting device is a self-light emitting type device having various characteristics such as luminance, driving voltage and response speed, and is not dependent on viewing angle, compared with a liquid crystal display.

The emission mechanism of the organic EL device will be described below. The holes injected from the anode to the HOMO of the hole injection layer HIL travel through the hole transport layer HTL to the light emitting layer EML and electrons move from the cathode to the light emitting layer through the electron injection layer EIL And is combined with holes to form an exciton. This exciton emits light as it falls to the ground state.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material used for an organic light emitting diode (OLED) which can be used for illumination, sensors and the like, which emits light by electric energy and is used for display applications.

In 1987, Eastman Kodak Company developed an electroluminescent device using TPD as a hole transport layer and Alq ₃ as a light emitting layer using the principle of organic EL devices (Appl, Phys. Lett., 51, 913, 1987). Thereafter, research on an electroluminescent device using an organic material is actively conducted. In recent years, commercialization of display and illumination components based on organic light emitting diodes (OLEDs) is underway. This development has been initiated by an important development described in EP 423 283 (WO 90/13148).

In recent years, Samsung Electronics and LG Electronics have introduced OLED mobile phones. Samsung SDI has produced 40-inch full HD TVs and 4-inch flapping displays as prototypes. At CES 2009, LG Electronics exhibited 15-inch AMOLED TV, digital picture frames with OLEDs from Samsung Electronics and Kodak, and 5-inch AMOLED portable mobile Internet devices from OQO. Sony also exhibited flexible OLED OLED, Sony Walkman with full touch screen, and AMOLED TV with thickness of about 0.9mm.

Organic light emitting diodes have several advantages over devices using inorganic materials. The organic compound is easily dissolved in an organic solvent to lower the production cost and the wavelength of the emitted light can be easily adjusted by mixing with other organic compounds.

Organic light emitting diodes can be used in applications such as flat panel displays, illumination, and backlighting by emitting light when current is supplied.

An object of the present invention is to provide a phenyl-pyridine-based metal complex compound having a carbosilyl structure that can be used for sensors and the like because of its extremely high electroluminescence (EL) intensity in the range of 700 to 750 nm.

The present invention also aims at providing a method for producing a metal complex. Another object of the present invention is to provide a light emitting device having a very high EL intensity at 700 to 750 nm by incorporating a metal complex compound in the light emitting layer.

In one preferred embodiment of the present invention, a phenylpyridine-based metal complex compound having a carbazole structure is synthesized to provide a light emitting device having a high electroluminescence intensity in the region of 700 to 750 nm by being partially or wholly used in the light emitting layer of the light emitting device.

The metal complex prepared according to the present invention has a very high electroluminescence (EL) intensity in the region of 700 to 750 nm and can be used for sensors and the like.

Generally, an organic light emitting diode includes at least one organic layer between an anode and a cathode. When current is supplied, the positive electrode injects holes and the negative electrode injects electrons. When holes and electrons meet in one molecule, excitons are formed in the molecules. Light is emitted when the exciton is relaxed via the light emission mechanism.

Excitons of organic light emitting diodes are produced with 75% triplet and 25% singlet, and phosphorescent organic light emitting diodes can theoretically achieve 100% internal quantum efficiency. Organic light emitting diodes using phosphorescent compounds emitted from a triplet excited state are disclosed in U.S. Patent No. 6,303,238.

Korean Patent Application No. 10-2005-7002654 discloses various phenylpyridine-based metal complexes. According to claims 57 and 58 of the aforementioned patent, the emitted light has the highest emission intensity at 520 nm or less, A light emitting device having a wavelength of about 480 nm is claimed.

   In addition, in reference to literature related to the conventional phenylpyridine-based iridium complexes, Korea Patent Application No. 10-2005-7003257 discloses a method for preparing a complex represented by Fac tris [4- {3 ', 5'-di [4 " 2 '' '' - {3 '' '' ', 5' '' '- di [4' Phenyl)} phenyl) -pyridine] iridium (III). The electroluminescence spectrum of this electroluminescence spectrum shows an emission peak at about 540 nm and a luminescence peak at about 700 to 750 nm The strength is very low.

Korean Patent Application No. 10-2005-7017798 discloses an electroluminescence spectrum of various phenylpyrazole-based iridium complexes, which shows a very low emission intensity over 600 nm as a whole.

The phenylpyridine-based metal complexes connected to the carbazole structure provided in the present invention show one emission peak at about 520 nm as shown in FIGS. 4 and 5, but the maximum emission peak larger than the emission peak at 700 to 750 nm see.

Preferred ancillary ligands include acetylacetonate (acac), picolinate (pic) dipivaloylmetanate (t-butyl acac). Additional non-limiting examples of ancillary ligands can be found in application publication WO 02/15545 A1, Lamansky et al.

The present invention provides, in a preferred embodiment, a method for synthesizing a metal complex. Hereinafter, the structure and effect of the present invention will be described in more detail with reference to examples. These embodiments are only for illustrating the present invention, and the scope of the present invention is not limited by these examples.

Example 1

Preparation of intermediate compounds:

Preparation of 6-bromonicotinaldehyde (com1)

4.7 g (20 mmol) of 2,5-dibromopyridine is added to purified ether (150 ml) and sufficiently stirred. In order to remove the 5 bubbles of 2,5-dibromopyridine in the substitution reaction of aldehyde, the reaction temperature is maintained at -75 ° C or less using an ice bath using liquid nitrogen / acetone. When the temperature of the reactor dropped below -75 ° C, 9.6 ml (24 mmol) of 2.5 M n-BuLi was slowly added to the reaction mixture for about 90 minutes, and 3.1 ml (40 mmol) of DMF was added thereto. The reactants were extracted with Eehtyl acetate (EA) and water, and the remaining water was removed using anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. The extracted reaction product was purified by column chromatography (silica gel, n-hexane / ethyl acetate = 10: 1) and dried. ^{56% yield: 1 H-NMR} (CDCl 3, ppm): δ 10.1 (s, 1H); 8.8 (s, 1 H); 8.0 (d, 1 H); 7.2 (d, 1 H)

 Preparation of 3,3 '- ((6-bromopyridin-3-yl) methylene) bis (9-ethyl-9H-

1.9 g (11.1 mmol) of 6-bromonicotinaldehyde and 4.7 g (24.58 mmol) of 9-ethylcarbazole are placed in 40 ml of acetic acid and stirred. Slowly add 20 ml (658 mmol) of HCl in small portions to the mixture. Additives are added under nitrogen atmosphere. Add all of the reactants, raise the temperature to 120 ° C and react for 24 hours. The reaction is terminated by neutralizing the reaction mixture with distilled water and stirring thoroughly with sodium bicarbonate. The neutralized reaction product is filtered with a vacuum flask, and the resulting powder is dissolved in methylene chloride (MC), then extracted with water and MC. The extracted reaction product was dried over anhydrous magnesium sulfate to remove residual moisture and the solvent was removed under reduced pressure. The extracted reaction product was purified by column chromatography (silica gel, MC / n-hexane = 3: 1) and dried. ^{43% yield: 1 H-NMR} (CDCl 3, ppm): δ δ 8.38 (s, 1H); 7.98 (d, 2H); 7.8 (d. 2H); 7.45 (d, 3H); 7.40 (t, 2H); 7.38 (t, 2H); 7.25 (s, 2 H); 7.22 (d, 1 H); 7.18 (d, 2H); 5.98 (s, 1 H); 4.38 (q, 4 H); 1.42 (t, 6H)

Preparation of 3-bromophenylboronic acid (com3)

25 g (106 mnol) of 1,3-dibromobenzene is added to purified ether (150 ml) and sufficiently stirred. The reaction is carried out at -75 ° C or below using a bath of liquid nitrogen / acetone. When the temperature of the reactor dropped below -75 ° C, 50.8 ml (127 mmol) of 2.5 M n-BuLi was added slowly, and the temperature was raised to room temperature. The reaction was allowed to proceed for 40 minutes. The reaction temperature was lowered to -75 ° C, g (318 mmol) of sodium hydroxide and the mixture is reacted for 12 hours to obtain a product. Add 300 ml of 2M HCl to distilled water and ice-filled beaker, stir the product several times, stirring thoroughly until all the ice is dissolved. The product is extracted with EA and water. Wash with distilled water enough to become neutral. The product is recrystallized using n-hexane to obtain the final purified product. ^{85% yield: 1 H-NMR} (CDCl 3, ppm): δ 8.24 (s, 1H); 8.1 (d, 1 H); 7.7 (d, 1 H); 7.4 (t, 1 H); 1.6 (s, 2H). IR (cm ^-1 ): 3432 (OH)

 Preparation of 3,3 '- ((6- (3-bromophenyl) pyridin-3-yl) methylene) bis (9-

A mixture of 5.5 g (10 mmol) of 3,3 '- (6-bromopyridin-3-yl) methylenebis (9-ethyl-9H-carbazole) and 3 g (15 mmol) of 3-bromophenylboronic acid in THF and 2M K ₂ CO ₃ is mixed in a 3: 1 (200 ml) solvent and stirred sufficiently. After completely replacing the reactor in which the reactant was added with nitrogen, 0.06 g (0.05 mmol) of Pd (pph ₃ ) ₄ was added, and the reactor was completely replaced with nitrogen. The temperature of the reactor, which is substituted with nitrogen, is raised to 120 ° C, and after 12 hours of reaction, the reaction is terminated by adding the reactant to 2N HCl solution. The reaction is neutralized with sodium bicarbonate and extracted with MC. The extracted reaction product was dried over anhydrous magnesium sulfate to remove the remaining water and the solvent was removed under reduced pressure. The extracted reaction product was purified by column chromatography (silica gel, MC / n-hexane = 10: 6) and dried. ^{84% yield, 1 H-NMR} (CDCl 3, ppm): δ 8.38 (s, 1H); 7.98 (d, 3H); 7.82 (s, 1 H); 7.42 (d, 3H); 7.4 (d, 3H); 7.38 (t, 2H); 7.36 (t, 3 H); 7.35 (d, 1 H); 7.24 (s, 2 H); 7.18 (d, 2H); 5.98 (s, 1 H); 4.38 (q, 4 H); 1.42 (t, 6H)

 Preparation of 2,3 '- ((6- (4', 6'-difluorobiphenyl-3-yl) pyridin-3-yl) methylene) bis (9-

5.3 g (10 mmol) of 2,4-difluorophenyl boronic acid and 2.4 g (15 mmol) of 3,3 '- ((6- (3-bromophenyl) pyridin- (200 ml) mixed with 3: 1 mixture of purified THF and 2M K ₂ CO ₃ and sufficiently stirred. After completely replacing the reactor in which the reactant was added with nitrogen, 0.06 g (0.05 mmol) of Pd (pph ₃ ) ₄ was added, and the reactor was completely replaced with nitrogen. The temperature of the reactor, which is substituted with nitrogen, is raised to 120 ° C, and after 12 hours of reaction, the reaction is terminated by adding the reactant to 2N HCl solution. The reaction is neutralized with sodium bicarbonate and extracted with MC. The extracted reaction product was dried over anhydrous magnesium sulfate to remove the remaining water and the solvent was removed under reduced pressure. The extracted reaction product was purified by column chromatography (silica gel, MC) and dried. ^{85% yield, 1 H-NMR} (CDCl 3, ppm): δ 8.33 (s, 1H); 7.97 (d, 2H); 7.82 (s, 1 H); 7.51 (d, 1 H); 7.49 (d, 2H); 7.46 (d, 3H); 7.45 (d. 2H); 7.43 (t, 1 H); 7.41 (d, 1 H); 7.36 (t, 2H); 7.35 (t, 2H); 7.28 (d. 2H); 7.26 (s, 2 H); 7.19 (s, 1 H); 7.16 (d, 1 H); 5.96 (s, 1 H); 4.36 (q, 4 H); 1.44 (t, 6H)

Preparation of Ir complex intermediates

3-yl) methylene) bis (9-ethyl-9H-carbazole) and 0.3 g of IrCl ₃ (1.0 mmol ) And 28 ml of a 3: 1 mixture of 2-ethoxy ethanol and H ₂ O are placed in a flask filled with nitrogen and reacted for 48 hours at 120 ° C under reflux. Dropping the reactants in distilled water produces yellow powder. The yellow powder was filtered using a vacuum flask and a glass filter, washed several times with distilled water, washed several times with ethanol to remove the unreacted ligand (com5) and by-products, and dried in a vacuum dryer at 60 ° C for 12 hours Ir complex intermediate.

Ir complex manufacture

3-yl) methylene) bis (9-ethyl-9H-carbazole) (1.8 g, 1.0 mmol) 1.5 g (2.2 mmol) of K ₂ CO _{3 and} 1.38 g (10 mmol) of K ₂ CO ₃ were placed in 25 ml of ethylene glycol and refluxed at 190 to 200 ° C under a nitrogen atmosphere. After the mixture is cooled to room temperature, distilled water is added and the resulting precipitate is separated by filtration and washed several times with distilled water. The crude product is dissolved in dichloromethane, and the remaining water is removed with anhydrous magnesium sulfate, followed by distillation under reduced pressure. The crude product is purified by flash chromatography on a silica column to give the pure product, formula (2).

(2)

Example 2

1.0 g (0.56 mmol) of the Ir complex intermediate and 250 mg of Na ₂ CO ₃ are added, and 0.224 g (2.24 mmol) of 2,4-pentadione is added to 20 ml of 2-ethoxyethanol. The mixture is refluxed at 120 < 0 > C for 2 hours to give a dark green solid. When the reaction is complete, the mixture is cooled to room temperature and placed in water. The mixture was filtered, dissolved in CH ₂ Cl ₂ solvent and purified by column chromatography (silica gel, methylene chloride) to obtain pure product, formula (3).

(3)

Example 3

An organic light emitting device was fabricated using ITO (indium tin oxide) -based substrates formed by forming two 4 mm wide ITO electrodes in stripes on one side of a 25 mm square glass substrate. First, poly (3,4-ethylenedioxythiophene): polystyrenesulfonic acid was coated on ITO (anode) of the ITO-bonded substrate by spin coating under the conditions of 3500 rpm of revolution and 40 seconds of coating time. Subsequently, drying was carried out in a vacuum dryer at 60 DEG C for 2 hours under reduced pressure to form a cathode buffer layer. The thickness of the obtained positive electrode buffer layer was about 40 nm. In the present invention, 100% of the compound synthesized in Example 1 was used as the light emitting layer or 80:20 of polyvinylcarbazole was coated on the anode buffer layer at a rotation speed of 3000 rpm for 30 seconds and dried at room temperature for 30 minutes A light emitting layer was formed, and the thickness of the light emitting layer was about 40 nm. In order to facilitate electron injection, an organic light emitting diode (1) was fabricated by depositing a 10 nm thick BCP layer, a 40 nm thick Alq ₃ layer, a 1 nm thick LiF layer and finally a 100 nm thick Al layer.

  1 shows a light-emitting device manufactured by using the compound synthesized in Example 1 as an EML layer.

 2 shows the UV-VIS absorption spectrum of the compound (Homoleptic) synthesized in Example 1 and the photoluminance excited at 365 nm.

 3 shows the UV-VIS absorption spectrum of the compound (Heteroleptic) synthesized in Example 2 and the photoluminance excited at 365 nm.

 4 shows the electroluminescence spectrum of the compound synthesized in Example 1 according to the operating voltage measured using 100% of the compound shown in FIG. 1 in the light emitting layer.

 5 shows the electroluminescence spectrum of the compound synthesized in Example 1 according to the use voltage measured by mixing PVK and 80:20 in the light emitting layer of the device shown in Fig.

 Figure 6 relates to phenyl-pyridine-based metal complexes linked to a carbazole structure.

Claims (4)

 A metal complex compound represented by the following formula (2) or (3). (2)

(3)

delete A light emitting device using an organic layer comprising a metal complex represented by the following Chemical Formula 2 or 3 (2)

(3)

delete

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