KR101570449B1 - Novel BODIPY derivative for green organic light-emitting diode dopant and method for preparing the same - Google Patents

Abstract

The present invention relates to a novel BODIPY derivative for a green organic light emitting device dopant, and more particularly to a BODIPY derivative for use in a BODIPY (4,4-difluoro-4-bora-3a, 4a-diaza- To a BODIPY derivative for a dopant of a green organic light emitting device and a method of manufacturing the same. The BODIPY derivative for a green organic light emitting diode dopant according to the present invention exhibits a maximum emission wavelength in a green region, exhibits improved brightness, has excellent luminous efficiency, and has excellent photophysical properties from an organic light emitting device to a dopant.

Description

TECHNICAL FIELD [0001] The present invention relates to a novel green organic light emitting diode (OLED) dopant and a method for preparing the same,

The present invention relates to a novel BODIPY derivative for a green organic light emitting device dopant, and more particularly to a BODIPY derivative for use in a BODIPY (4,4-difluoro-4-bora-3a, 4a-diaza- To a BODIPY derivative for a dopant of a green organic light emitting device and a method of manufacturing the same.

Organic light-emitting diodes (OLEDs) have been growing in popularity over the past few years due to their low cost, full color and flat panel display characteristics.

Among OLED display technologies, guest-host doped emitter systems are doped with a single host material with optimized transmission and luminescence properties, and can be efficiently used in a wide variety of fields ranging from high-brightness fluorescent dopants to electroluminescence have. Such a light emitting device system can also improve operational stability by minimizing non-radiation possibilities and transmitting electrical exciters with high emission and stable doping sites.

In order to improve the efficiency of brightness, stability, etc. of the OLED device, it is necessary to introduce an excellent fluorescent dopant into the host material. Therefore, there is a need to develop new dopants with excellent color purity, stability and high efficiency.

On the other hand, diamond-difluoro Robo chair - s - indazol sensor (difluoroboradiaza- s -indacene, BODIPY) is a kind of excellent fluorophores, has a high quantum yield, a large molar extinction coefficient, excellent chemical, thermal and optical physical properties. Research has been conducted to develop new BODIPY derivatives according to the potential properties of BODIPY and to apply them as light emitting devices, chemical sensors, biological markers and photovoltaic cells.

A number of studies have been conducted on such BODIPY derivatives to obtain derivatives of the BODIPY structure through modification of the pyrrole core, fusion of aromatic rings in the BODIPY core, and rearrangement of the nitrogen atom and the 8-carbon atom in the formation of aza-BODIPY .

Korean Patent No. 10-1035236 Korean Patent No. 10-0874761

 Synthesis, structure and luminescence characteristics of aluminum complexes containing BODIPY chromophore, KAIST (2008), JS.

In order to solve the problems of the prior art as described above, the present invention relates to a novel BODIPY derivative prepared by substituting two arylamine moieties for BODIPY, which is used as a green dopant of an organic light emitting device and exhibits excellent photophysical properties And the present invention has been completed on the basis thereof.

The present invention relates to a novel green organic light emitting diode dopant BODIPY derivative having excellent light emitting efficiency and excellent luminous efficiency and exhibiting excellent photophysical properties from an organic light emitting device to a dopant, And a method thereof.

In order to accomplish the above object, the present invention provides a BODIPY derivative for a green dopant of an organic light emitting device represented by the following formula (1).

[Chemical Formula 1]

In the formula (1)

또는

이다R is

or

to be

The present invention also provides a green dopant for organic light emitting devices represented by Formula 1, wherein BODIPY (4,4-difluoro-4-bora-3a, 4a-diaza-s-indacene) BODIPY < / RTI >

Specifically,

(S1) preparing a compound of Formula 3 by reacting trimethylsilylethyne with Sonogashira to a compound of Formula 2 below;

(S2) removing the functional group from the compound of Formula 3 to prepare a compound of Formula 4;

(S3) reacting the compound of formula (IV) with 4-bromobenzenaldehyde by Sonogashira reaction to prepare a compound of formula (5); And

(S4) reacting the compound of Formula 5 with 3-ethyl-2,4-dimethyl-1H-pyrrole to produce a compound of Formula 1;

Lt; / RTI >

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

In the formulas (1) to (5)

R is the same as defined in the above formula (1).

The present invention also provides a green organic light emitting device comprising the BODIPY derivative represented by the above formula (1) as a dopant.

The BODIPY derivative of the present invention exhibits a maximum emission wavelength in the green region, exhibits improved brightness, is excellent in luminous efficiency, can realize efficient charge transporting characteristics, and has excellent photophysical properties as an organic light emitting element to a dopant have.

FIG. 1 is a graph showing the results of UV-vis absorption spectra of a BODIPY derivative represented by Chemical Formula 1 prepared according to an embodiment of the present invention. FIG.

Hereinafter, the present invention will be described in detail.

Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Repeated descriptions of the same technical constitution and operation as those of the conventional art will be omitted.

The present invention provides a BODIPY derivative for a green dopant of an organic light emitting device represented by the following formula (1).

[Chemical Formula 1]

In the formula (1)

또는

이다.R is

or

to be.

The novel BODIPY derivatives represented by the above-mentioned formula (1) include 4,4-difluoro-4-bora-3a, 4a-diaza -s-indacene, BODIPY) is bonded to an arylamine residue of 9-phenylcarbazole or triphenylamine.

The novel BODIPY derivative represented by formula (1) according to the present invention can be prepared by coupling BODIPY (4,4-difluoro-4-bora-3a, 4a-diaza-s-indacene) with an arylamine residue.

The process for preparing a novel BODIPY derivative of the present invention can be represented by the following reaction scheme 1 representatively. The production method of the present invention is not limited to the following Reaction Scheme 1, and it is a matter of course that various organic synthesis methods can be used for the production.

[Reaction Scheme 1]

In the above Reaction Scheme 1, R is as defined in Formula 1 above.

The method for preparing the BODIPY derivative represented by the formula (1) of the present invention will be described in detail with reference to the above Reaction Scheme 1.

(S1) Preparation of compound of formula (3)

The arylamine iodide of formula (2) and trimethylsilylethyne are reacted with Sonogashira to prepare the compound of formula (3).

The Sonogashira reaction can be carried out under palladium catalyst in a cross-coupling reaction to form a carbon-carbon bond in organic synthesis. That is, by the Sonogashira reaction, a carbon-carbon bond can be formed between trimethylsilylethyne and the compound of formula (2) having an aryl group at the terminal to obtain the compound of formula (3).

(S2) Preparation of compound of formula (4)

The compound of formula (III) is prepared by removing the functional group from the compound of formula (III). At this time, from the compound of Formula 3, potassium hydroxide (KOH) is added under a solvent such as methanol and tetrahydrofuran (THF) and reacted to deprotect the functional group to obtain the activated compound of Formula (4).

(S4) Preparation of BODIPY derivative of formula (1)

Finally, the compound of Formula 5 and 3-ethyl-2,4-dimethyl-1H-pyrrole are reacted to prepare the BODIPY derivative of Formula 1 of the present invention.

Specifically, trifluoroacetic acid was added in a catalytic amount to a mixed solution in which the compound of formula 5 and 3-ethyl-2,4-dimethyl-1H-pyrrole were dissolved in dichloromethane as a solvent, and the mixture was stirred at room temperature for 10 hours Lt; / RTI > Then, the reaction solution was treated with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and stirred for 3 hours. Then, triethylenamine and boron trifluoride di Ethyl etherate was added and stirred at room temperature for 10 hours. Next, the reaction product is washed with deionized water, and the organic phase is separated, dried with magnesium sulfate, filtered and concentrated to obtain a BODIPY derivative of the formula (1).

The BODIPY derivative of the present invention prepared as described above may be represented by the following general formula (1a) or (1b).

[Formula 1a]

[Chemical Formula 1b]

The present invention also provides a green organic light emitting device comprising the BODIPY derivative represented by the formula (1) as a dopant.

The BODIPY derivative represented by the formula (1) of the present invention can be applied as a dopant for a green organic light emitting device by a conventional process known in the art. The green organic light emitting device to which the BODIPY derivative of the formula (1) It is possible to provide an improved light-emitting wavelength and an improved light-emitting efficiency, as well as to realize an efficient charge transporting property and an excellent photophysical property as an organic light emitting device to a dopant.

Hereinafter, the present invention will be described in more detail with reference to examples. These embodiments are for purposes of illustration only and are not intended to limit the scope of protection of the present invention.

The reagents and solvents used in the following examples were purchased from Aldrich and TCI Chem., And used without purification.

In addition, ¹ H and ¹³ C NMR spectra were measured using a JEON JNM-ECP FT-NMR spectrometer operating at 500 MHz and 125 MHz, respectively, and infrared spectra were measured using a Shimadzu Prestige-21 FT-IR spectrophotometer. Samples were measured by KBr pellet method and scanned in the range of 4000-400 cm ^-1 . The UV-vis absorption spectrum was measured using a Scinco S-3100 spectrophotometer, and the photoluminescence (PL) spectrum was measured using a CARY Eclipse Varian fluorescence spectrophotometer. The HOMO value was calculated from the oxidation potential and the LUMO value was calculated based on the lowest energy absorption limit of the HOMO value and the UV-vis absorption spectrum.

The preparation of the following examples is according to the following Reaction Scheme 1.

[Reaction Scheme 1]

In the above Reaction Scheme 1, R is as defined in Formula 1 above.

Example 1. Preparation of BODIPY derivatives of formula (Ia)

(1) 9- (4-Trimethylsilanylethynyl -phenyl) -9 H -carbazole (3a) Synthesis

Dissolving the compound 2a 1g (2.7mmol) solution of tetrahydrofuran (THF) / triethylamine (TEA) (1: 1) CuI 0.0251g (0.135mmol) and Pd (PPh ₃₎ in ₂ Cl ₂ 0.094g (0.135 mmol), and then 0.26 g (2.7 mmol) of ethynyltrimethylsilane was added. Followed by stirring for 8 hours while maintaining the temperature at 45 캜. When the filter after cooling the stirred solution (4-ethynyl-trimethylsilanyl-phenyl) black solid product, 9- -9 H-carbazole -9 (3a) 0.89g (yield: 97%) was obtained (mp: 150 ~ 152 ° C)

_{^{1 H NMR (Chloroform-d 1}} ): δ 0.31 (s, 9H), 7.34-7.28 (m, 2H), 7.43-7.40 (m, 4H), 7.56-7.51 (m, 2H), 7.73-7.69 (m , 2H), 8.17-8.12 (m, 2H) ppm.

¹³ C-NMR (Chloroform-d ₁ ):? 95.4, 104.2, 109.7, 120.2, 120.4, 122.1, 123.5, 126.0, 126.7, 133.5, 137.7, 140.5 ppm.

(2) 9- (4-Ethynyl -phenyl) -9 H -carbazole (4a) Synthesis

To a solution of 1 g (2.94 mmol) of compound 3a in tetrahydrofuran, 0.164 g / 2 ml of potassium hydroxide / methanol was added slowly using a dropping funnel, and the mixture was stirred at room temperature for 1 hour. The solvent was concentrated under reduced pressure (4-ethynyl-phenyl) black solid product, 9- -9 H-carbazole (4a) 0.73g: was obtained (yield 94%) (mp: 106~107 ℃ ).

_{^{1 H NMR (Chloroform-d 1}} ): δ 3.19 (s, 1H), 7.33-7.29 (m, 2H), 7.44-7.42 (m, 4H), 7.57-7.55 (m, 2H), 7.75-7.73 (m , 2H), 8.17-8.14 (m, 2H) ppm.

¹³ C NMR (Chloroform-d ₁ ):? 78.1, 82.9, 109.7, 120.3, 120.4, 121.0, 123.6, 126.1, 126.8, 133.7, 138.1, 140.5 ppm.

(3) Synthesis of 4- (4-Carbazol-9-yl-phenylethynyl) -benzaldehyde (5a)

0.0251 g (0.135 mmol) of CuI and 0.094 g (0.135 mmol) of Pd (PPh ₃ ) ₂ Cl ₂ were added to a tetrahydrofuran / triethylamine solution (1: 1) in which 1 g (3.74 mmol) 0.86 g (3.74 mmol) of the compound 4-Iodobenzaldehyde was added and the mixture was stirred for 8 hours while maintaining the temperature at 45 ° C. After stirring, the reaction product was separated and purified by chromatography (n-hexane: dichloromethane = 4: 1 (v / v)) to obtain an orange solid product, 9- {4- [4- (5,5- , 3] dioxan-2-yl) -phenylethynyl] -phenyl} -9 H -carbazole (5a).

IR (KBr) ν 1452, 1264 (CHO) cm ^-1 .

_{^{1 H NMR (Chloroform-d 1}} ): δ 7.21-7.32 (m, 6H), 7.40-7.81 (m, 6H), 7.89-7.92 (d, J = 10Hz, 2H), 8.13-8.15 (d, J = 10 Hz, 2H), 10.04 (s, 1H) ppm.

¹³ C NMR (Chloroform-d ₁ ): δ 76.85, 77.10, 77.36, 109.80, 120.44, 120.52, 126.20, 126.98, 129.75, 132.28, 133.43 ppm.

4 of the formula 1a BODIPY derivatives (2,6-Diethyl-4,4-difluoro -1,3,5,7-tetramethyl-8- [4- (2- (4-ethynyl-phenyl) -9 H - carbazole) phenyl] -4-bora-3a, 4a-diaza-s-indacene) Synthesis

0.2 g (0.539 mmol) of the compound 5a was dissolved in dichloromethane and reacted with 2,4-dimethyl-3-ethylpyrrole 0.15 ml (1.304 mmol) of Three drops of triroolacetic acid were added and stirred for 10 hours. DDQ (2,3- dichloro-5,6-dicyano-1,4-benzoquinone), the insert then stirred for 3 hours BF ₃ 2ml and triethyl amine into a 10ml was stirred for 10 hours. As a result, 0.22 g (yield: 68%) of a red product BODIPY-CA (1a) was obtained (mp: 257 to 259 ° C).

IR (KBr) ν 1420 (boron) cm ^-1 .

¹ H NMR (Chloroform-d ₁ ): δ 0.82-1.55 (m, 6H), 2.15-2.51 (m, 6H), 3.68-3.83 (m, 8 H) ppm.

¹³ C NMR (Chloroform-d ₁ ):? 12.04, 14.23 14.71, 17.16, 22.80, 23.20, 29.46, 29.80, 32.02, 101.11, 127.06, 128.33, 132.12, 133.34, 139.78, 139.98, 153.87 ppm.

Example 2. Preparation of BODIPY derivative of formula (Ib)

(1) Synthesis of benzenamine, N, N- diphenyl-4 - [(trimethylsilyl) ethynyl] (3b)

0.0251 g (0.135 mmol) of CuI and 0.094 g (0.135 mmol) of Pd (PPh ₃ ) ₂ Cl ₂ were added to a solution of tetrahydrofuran / triethylamine (1: 1) 0.26 g (2.7 mmol) of thionyltrimethylsilane was added. Followed by stirring for 8 hours while maintaining the temperature at 45 캜. After stirring, the solution was cooled and filtered to obtain 0.89 g (yield: 97%) of a black solid product, benzene amine, N, N -diphenyl-4 - [(trimethylsilane) ethynyl] 149 [deg.] C).

_{^{1 H NMR (Chloroform-d 1}} ): δ 0.24 (s, 9H), 6.92 (m, 2H), 7.09 (m, 6H), 7.28 (m, 6H,) ppm.

¹³ C NMR (Chloroform-d ₁ ):? 98.1, 106.3, 119.2, 123.2, 124.5, 126.5, 129.8, 135.6, 142.0, 142.8 ppm.

( 2) Synthesis of 4-Ethynyl- N, N- diphenylaniline (4b)

Compound 3b 0.164 g / 2 ml of a solution of potassium hydroxide / methanol was added slowly to the tetrahydrofuran solution in which 1 g (2.94 mmol) of triethylamine was dissolved by using a dropping funnel, and the mixture was stirred at room temperature for 1 hour. After concentrating the solvent under reduced pressure, 0.65 g (yield: 78%) of 4-ethynyl- N, N -diphenyl aniline (4b) as a black solid product was obtained (mp: 107-108 ° C).

_{^{1 H NMR (Chloroform-d 1}} ): δ 3.06 (s, 1H), 7.03 (m, 2H), 7.12 (m, 6H), 7.32 (m, 6H) ppm.

¹³ C NMR (Chloroform-d ₁ ):? 777.2, 83.9, 114.8, 122.1, 123.7, 125.0, 129.4, 133.1, 146.4, 147.1 ppm.

(3) Synthesis of (4-Ethynyl- N, N- diphenylaniline) -benzaldehyde (5b)

0.0251 g (0.135 mmol) of CuI and 0.094 g (0.135 mmol) of Pd (PPh ₃ ) ₂ Cl ₂ were added to a tetrahydrofuran / triethylamine solution (1: 1) in which 1 g (3.73 mmol) 0.86 g (3.74 mmol) of the compound 4-Iodobenzaldehyde was added and the mixture was stirred for 8 hours while maintaining the temperature at 45 ° C. After stirring, the mixture was separated and purified by chromatography (n-hexane: dichloromethane = 4: 1 (v / v)) to obtain a dark green solid {4- [4- (5,5- (Yield: 58%) (mp: 178 캜) of the title compound (5b).

IR (KBr) ν 1394, 1264 (CHO) cm ^-1 .

_{^{1 H NMR (Chloroform-d 1}} ): δ 0.80-0.84 (t, 2H), 1.24-1.28 (d, J = 5 Hz, 2H), 3.65-3.80 (d, J = 10Hz, 4H), 5.44 (s , 2H), 6.92-7.25 (m, 4H), 7.66-7.91 (m, 8H), 10.01 (s, 1H) ppm.

¹³ C NMR (Chloroform-d ₁ ): δ 21.95, 23.10, 30.40, 100.83, 126.55, 127.02, 129.86, 136.71, 144.64, 192.19 ppm.

(4) A BODIPY derivative of the formula (1b) (2,6-Diethyl-4,4-difluoro-1,3,5,7-tetramethyl-8- [4- 2- (4-Ethynyl- N, N- diphenylaniline) phenyl] -4-bora-3a, 4a-diaza-s-indacene] Synthesis

0.25 g (0.536 mmol) of the compound 5b was dissolved in dichloromethane, 0.15 ml (1.304 mmol) of 2,4-dimethyl-3-ethylpyrrole Three drops of triple orthoacetic acid were added and stirred for 10 hours. After stirring for 3 hours, 2 ml of BF ₃ and 10 ml of triethylamine were added and the mixture was further stirred for 10 hours. As a result, 0.22 g (yield: 66%) of a red solid product BODIPY-TA (1b) was obtained (mp: 261-262 ° C).

IR (KBr) υ 1405 (boron) cm ^-1 .

_{^{1 H NMR (Chloroform-d 1}} ): δ 0.86-0.99 (m, 6H), 1.24-1.55 (m, 6H), 2.30-2.54 (m, 8H), 7.25-7.45 (d, J = 8.71 Hz, 2H ), 7.60-7.62 (d, J = 8.25 Hz, 2H), 7.78-7.80 (d, J = 8.71 Hz, 2H) ppm.

¹³ C NMR (Chloroform-d ₁ ): δ 12.03, 12.65, 14.23, 14.74, 17.18, 17.37, 22.76, 31.69, 109.82, 120.39, 120.51, 123.68, 126.18, 126.98, 128.70, 130.63, 132.63, 133.26, 136.16, 137.98 , 138.31, 140.57, 154.16 ppm.

NMR, IR, UV-vis, PL spectroscopies and HOMO-LUMO energy levels were measured using the BODIPY derivatives represented by formulas 1a and 1b prepared in Examples 1 and 2, 1 and Table 1 below. FIG. 1 shows UV-vis spectra of the BODIPY derivatives represented by the above formulas (1a) and (1b).

division Example 1 The compound of formula 1b NPB Tg (占 폚) 243 260 - UV? _Max (nm) ^a 526 524 - PL? _Max (nm) ^a 552 551 - E _ox (eV) ^b 0.82 0.84 0.55 HOMO (eV) ^c 5.67 5.69 5.40 LUMO (eV) ^c 3.40 3.42 2.50 E _g (eV) 2.27 2.27 2.90 [Note] a: In dichloromethane (Ca. 1 × 10 ^-6 M)
b: Oxidation potential relative to Ag / AgCl electrode
c: HOMO = (E _{ox +} 4.85) eV / LUMO = (HOMO-E _g ) eV

As shown in Fig. 1 and Table 1, the UV-vis absorption peaks of the BODIPY derivatives represented by formulas 1a and 1b prepared in Examples 1 and 2 were observed at 526 nm and 524 nm, respectively. The emission peaks of the BODIPY derivatives represented by the general formulas (1a) and (1b) were observed in the green region of 552 nm and 551 nm, respectively, and both of the derivatives showed similar photoluminescence intensity.

From the band gap energy (Eg) evaluated from the measurement of the circulating current and the beginning of absorption, the highest molecular orbital energy (HOMO) of the BODIPY derivative represented by the formulas 1a and 1b prepared in Examples 1 and 2 and The lowest molecular orbital (LUMO) is compared with N, N' -di (naphthalen-1-yl) -N, N' -diphenyl-benzidine (NPB) most widely used as a major transport material in organic light emitting devices Respectively.

The HOMO / LUMO energy values of the BODIPY derivatives represented by Formulas 1a and 1b prepared in Examples 1 and 2 were 5.67 / 3.40 and 5.69 / 3.42, respectively, and the calculated HOMO-LUMO energy gap (Eg) was 2.27. For efficient operation of the device, the layer adjacent to the HOMO of the emitter (bandgap) and the layer adjacent to the LUMO should be in parallel with each other, and the BODIPY derivative represented by the formulas 1a and 1b prepared in Examples 1 and 2, Lt; RTI ID = 0.0 > a < / RTI > green dopant in the light emitting device.

Although the present invention has been described in terms of the preferred embodiments mentioned above, it is possible to make various modifications and variations without departing from the spirit and scope of the invention. It is also to be understood that the appended claims are intended to cover such modifications and changes as fall within the scope of the invention.

Claims (8)

A BODIPY derivative for green dopant of organic electroluminescent device represented by the following formula (1a) or (1b):
[Formula 1a]

[Chemical Formula 1b]

(S1) preparing a compound of Formula 3 by reacting trimethylsilylethyne with Sonogashira to a compound of Formula 2 below;
(S2) removing the functional group from the compound of Formula 3 to prepare a compound of Formula 4;
(S3) reacting the compound of formula (IV) with 4-bromobenzenaldehyde by Sonogashira reaction to prepare a compound of formula (5); And
(S4) reacting the compound of formula (5) with 3-ethyl-2,4-dimethyl-1H-pyrrole;
(1) or (2), wherein R < 1 > and R < 2 >
[Formula 1a]

[Chemical Formula 1b]

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

In the formulas (2) to (5)
R are each independently the same or different

or

to be. delete delete 3. The method of claim 2,
Wherein the Sonogashira reaction in steps (S1) and (S3) is performed in the presence of a palladium catalyst. 3. The method of claim 2,
Wherein the step (S2) is carried out by reacting potassium hydroxide (KOH) in an organic solvent. 3. The method of claim 2,
In the step (S4), the compound of Chemical Formula 5 and 3-ethyl-2,4-dimethyl-1H-pyrrole are reacted under trifluoroacetic acid catalyst to obtain 2,3-dichloro-5,6-dicyano- -Benzoquinone, triethylamine, and boron trifluoride diethyl etherate, and then reacting the resulting mixture. The method for producing the BODIPY derivative for green dopant according to claim 1, A green organic light emitting device comprising a BODIPY derivative represented by the following formula (1a) or (1b) as a dopant:
[Formula 1a]

[Chemical Formula 1b]

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