KR102176917B1 - New organic light emitting mesogenic copolymers with composition containing iridium(III) complex chromophore, capable of polarized light emission and method for preparing the same - Google Patents

Abstract

The present invention relates to a novel organic light-emitting mesogenic copolymer capable of polarized emission including an iridium (III) complex chromophore and a method for preparing the same, wherein the copolymer prepared through the present invention has high solubility, thermal stability and mechanical strength. It has excellent light emission characteristics with strong intensity, which can lead to improvement of the light emission efficiency of OLED.

Description

New organic light emitting mesogenic copolymers with composition containing iridium(III) complex chromophore, capable of polarized light emission and method for preparing the same}

The present invention relates to a novel organic light-emitting mesogenic copolymer comprising an iridium (III) complex chromophore and capable of emitting polarized light and a method for preparing the same.

A light emitting display device using an organic light emitting diode (OLED) does not require a separate light source, unlike a liquid crystal display (LCD), so it can be manufactured with a lighter and thinner thickness, as well as high luminance. With high-quality characteristics such as low power consumption, the range of application is expanding as a next-generation display device for portable electronic devices.

The basic structure of a light-emitting display device using an OLED is a structure in which an organic light-emitting layer is interposed between an anode and a cathode, and electrons and holes are recombined in the organic light-emitting layer to form excitons, which are emitted while transitioning to a low energy state. It is driven on the principle of an electroluminescence phenomenon in which energy is emitted as light, and various studies are being conducted to improve luminous efficiency.

Korean Patent Application Publication No. 10-2017-0114059 discloses an OLED having a light emitting layer including aligned liquid crystal molecules. By providing a light emitting layer in which the electroluminescent liquid crystals are aligned according to the alignment direction of the alignment layer, it is possible to implement a 3D OLED display without reducing light efficiency.Since left circularly polarized light and right circularly polarized light can be implemented at the same time, polarized light can be emitted to maintain light efficiency. Yet, it can exert the effect of reducing the process cost.

Recently, a study has been reported to produce light with high circular polarization by controlling a thin layer that generates light inside the OLED, moving away from the conventional method of increasing the intensity of light to improve OLED light efficiency (Advanced Materials, 2017, 1700907). According to the research results, it is possible to generate light with high polarization by adding a small amount of chiral molecules that can be aligned by twisting liquid crystal polymers to the polymer OLED emitting layer. In general, liquid crystalline, that is, arrayable OLED light emitting materials produce light with linear polarization. When this linearly polarized light passes through an anisotropic polymer layer twisted by chiral molecules, the linearly polarized light changes into circular polarization. It is reported that the light efficiency can be remarkably improved and the light efficiency can theoretically be raised to 100%.

The structure of a polymer capable of inducing polarized light emission is when a rigid rod-shaped mesogen is located in the main chain or in the side chain, and cures substances with UV-curable functional groups on both sides of the mesogen. By inducing the orientation of the mesogen, polarized light emission can also be obtained. In addition, polymers having mesogens like these may exhibit a liquid crystal phase.

Liquid crystal is an intermediate phase between a liquid and a solid, and the anisotropic mesogen structure in a specific temperature range or a specific concentration range shows a weak directional order and positional order like a solid, and has liquid fluidity. Therefore, when the organic light emitting molecules have a liquid crystal phase, the molecules are oriented in one direction, thereby inducing highly polarized light emission.

The hard rod-shaped calamitic liquid crystal has an aromatic or cycloaliphatic structure located in the core and, in some cases, may contain side chain substituents and polar end groups. Calamitic liquid crystals mainly have nematic and smectic meso phases. In a nematic phase, molecules are aligned parallel to the major axis of adjacent molecules. Molecules are oriented with one local director and have high fluidity due to the lack of regularity in the liquid crystal phase. Smatic has a more diverse liquid crystal phase than nematic phase because molecules are layered and oriented in one direction. Research results have been reported that the liquid crystal light-emitting material improves the charge transport ability in the section forming the liquid crystal phase, but it was found that the Smetic A and Smatic C phases show excellent charge mobility in a more aligned form. However, in the case of Smetic A and C phases, processing and orientation are difficult due to their high viscosity, so they are mainly used in fields intended for charge transport.

Structures most commonly used for mesogenic light-emitting materials include fluorene, thiophene, and benzothiadiazole. Among them, the fluorene-based polymer emits blue light with high efficiency in both photoluminescence and electroluminescence, is thermally stable, and has the advantage of improving solubility and processability by introducing various substituents at the 9th carbon position. Among the luminescent polymers, it has been actively studied.

In order to increase the light efficiency of OLED, it is urgent to develop a light-emitting material that can generate polarized light, and in particular, a linear polymer as a polymer is suitable as a material that can generate polarized light because it can be aligned in one direction. There is a need for the development of various kinds of liquid crystal light-emitting polymer materials.

Accordingly, the present inventors completed the present invention by manufacturing a novel type of organic light-emitting mesogenic material, enabling wide application to a full-color display, a backlight light source for a liquid crystal display, and a next-generation solid light-emitting light source.

Republic of Korea Patent Publication No. 10-2017-0114059 (Name of the invention: organic light-emitting diode having an emission layer containing aligned liquid crystal molecules, Applicant: Hanyang University Industry-Academic Cooperation Foundation, Publication Date: October 13, 2017) Republic of Korea Patent Registration No. 10-1745371 (Name of invention: Hockey stick type reactive mesogen compound and its manufacturing method, Applicant: Keumo Institute of Technology Industry-Academic Cooperation, Registration date: June 2, 2017) Korean Patent Registration No. 10-1724588 (Name of invention: bent-nuclear imesogen compound and its manufacturing method, Applicant: Keumo Institute of Technology Industry-Academic Cooperation Foundation, registration date: April 3, 2017)

An object of the present invention is to provide a novel organic light-emitting mesogenic copolymer including an iridium (III) complex chromophore and capable of emitting polarized light and a method for producing the same.

The copolymer including the novel mesogenic iridium (III) complex of the present invention is characterized by represented by the following formula (1).

[Formula 1]

(The R1 and R2 are each independently selected from hydrogen or an alkyl group having 1 to 10 carbon atoms, and m and n are each independently an integer of 10 to 10000)

The copolymer comprising the mesogenic iridium complex is provided with a boron-containing biphenyl derivative compound; Providing a fluorene derivative compound; Providing a heterolaptic iridium complex; Polymerizing the boron-containing biphenyl derivative compound, fluorene derivative compound, and heterolabtic iridium complex; And capping the polymer end group with a phenyl derivative after the polymerization step.

The biphenyl derivative compound containing boron may be represented by the following formula (2).

[Formula 2]

The fluorene derivative compound may be specifically represented by Formula 3 below.

[Formula 3]

(The R1 and R2 are each independently selected from hydrogen or an alkyl group having 1 to 10 carbon atoms)

The heteroraptic iridium complex may be specifically represented by the following Formula 4.

[Formula 4]

(The X is selected from Cl, Br, and I)

The polymerization reaction is characterized in that the reaction is performed under a palladium-based catalyst in an aqueous K ₂ CO ₃ solution.

In addition, the phenyl derivative may be selected from bromobenzene or phenylboronic acid.

The copolymer including the mesogenic iridium complex represented by Formula 1 is characterized in that it is prepared by the following Reaction Formula 1.

[Scheme 1]

In yet another aspect, the present invention can provide a lyotropic liquid crystal composition containing the compound of Formula 1 above.

The present invention relates to a novel organic light-emitting mesogenic copolymer capable of polarized emission including an iridium (III) complex chromophore and a method for preparing the same, wherein the copolymer prepared through the present invention has high solubility, thermal stability and mechanical strength. It has excellent light emission characteristics with strong intensity, which can lead to improvement of the light emission efficiency of OLED.

1 shows the FT-IR spectrum of the iridium copolymer prepared in Example 1-6 of the present invention.
2 shows a ¹ H NMR spectrum of the iridium copolymer prepared in Example 1-6.
3 shows the UV-vis absorption spectrum of the iridium copolymer prepared in Example 1-6.
4 shows the emission spectrum (PL spectra) of the iridium copolymer prepared in Example 1-6.
5 to 9 show POM (Polarized Optical Microscope) images of the iridium copolymer prepared in Example 1-6.

Hereinafter, a preferred embodiment of the present invention will be described in detail. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, it is provided to sufficiently convey the spirit of the present invention to those skilled in the art so that the contents introduced herein are thorough and complete.

<Example 1. Preparation of mesogenic iridium fluoropolymer>

A copolymer was prepared according to Scheme 1 below by Suzuki-Miyaura coupling reaction.

[Scheme 2]

In addition, to synthesize Z (dibromofluorene ligand) of Scheme 2, each intermediate used in the process of Scheme 3 was synthesized.

[Scheme 3]

Example 1-1. Synthesis of compound 1

[Scheme 4]

After dissolving 5-bromo-2-methylpyridine (5 g, 0.0291 mol) in diethyl ether anhydrous (300 ml) in a nitrogen atmosphere reactor, cool it to -78°C using dry ice, so that the inside of the reactor is sufficiently cooled- The mixture was stirred for 1 hour while maintaining at 78°C. After stirring, 2.5M n-butyllithium (15.1 ml, 0.0378 mol) was slowly added dropwise, and the mixture was stirred at -78°C for 2 hours. After another 2 hours, 2,7-dibromo-9-fluorenone (11.7 g, 0.0349 mol) was divided and added several times. As time passed, the dry ice gradually melted and the temperature gradually increased to reach room temperature (25°C), and the reaction was performed for about 12 hours until reaching room temperature. After the reaction was completed, the organic layer was extracted with distilled water and ethyl acetate, and the extracted organic layer was washed with distilled water. After removing water from the washed organic layer with anhydrous magnesium sulfate, magnesium sulfate was removed by a reduced pressure filter, and the remaining filtrate was distilled under reduced pressure to remove the solvent. The product from which the solvent was removed was purified by silica gel column chromatography. Thereafter, unreacted products were removed with dichloromethane, and the purified product was obtained using ethyl acetate. The purified product was recrystallized with ethanol and distilled water to obtain a white solid (8.49 g). Yield: 67.64%

¹ H-NMR (400 MHz, acetone-d ₆ , in ppm): 2.43 (s, 3H), 5.73 (s, H), 7.14 (d, H, J = 7.81 Hz), 7.46 (d, 2H, J = 1.49 Hz), 7.58 (m, 3H), 7.79 (d, 2H, J = 8.18 Hz), 8.40 (d, H, J = 2.23 Hz).

FT-IR (KBr pellet, cm ^-1 ): 3144 (OH stretch), 2853 (CH stretch, CH3-Ar), 1449 (C=C aromatic stretch), 1406 (CN stretch), 1246, 1171 (CO stretch) , (C-Br stretch).

Example 1-2. Synthesis of compound 2

[Scheme 5]

Compound 1 (compound 1) (8.49 g, 0.0197 mol) and dried benzene (100 ml) were added to the reactor in a nitrogen atmosphere, and trifluoromethanesulfonic acid (2.3 ml, 0.0256 mol) was slowly added dropwise to prepare a mixture. The mixture after dropwise addition was stirred for 4 hours and refluxed. After completion of the reaction, the mixture was poured into an aqueous sodium bicarbonate solution and extracted with EA (ethyl acetate). The extracted organic layer was washed with distilled water, moisture was removed with anhydrous magnesium sulfate, and magnesium sulfate was removed again with a reduced pressure filter, leaving only the filtrate. The obtained filtrate was distilled under reduced pressure to remove the solvent, and the product obtained after removing the solvent was purified by silica gel column chromatography using dichloromethane. The purified product was recrystallized with ethanol and distilled water to obtain a white solid (8.49 g). Yield: 89.78%

¹ H-NMR (400 MHz, acetone-d ₆ , in ppm): 2.45 (s, 3H), 7.21 (m, 3H), 7.32 (m, 3H), 7.50 (m, H), 7.64 (m, 4H ), 7.92 (d, 2H, J = 8.39 Hz), 8.27 (d, H, J = 2.24 Hz).

FT-IR (KBr Pellet, cm ^-1 ): 3042 (CH aromatic stretch), 1508, 1492 (C=C stretch), 1451 (CN stretch), 700 (C-Br stretch).

Example 1-3. Synthesis of compound 3

[Scheme 6]

Compound 2 (8.49 g, 0.0173 mol) and pyridine:water (3:1) (300 ml) were added to the reactor, potassium permanganate (40.96 g, 0.259 mol) was divided into 10 times and refluxed (at this time If you add potassium permanganate, the solution becomes purple, but when the catalyst becomes manganese oxide, the purple disappears and the solution becomes transparent, so add potassium permanganate separately, and add potassium permanganate every time the purple disappears, and perform a total of 10 times). After completion of the reaction, the solution was filtered under reduced pressure with distilled water to remove manganese oxide, and a filtrate was obtained. After reducing the amount of the solvent in the filtrate, HCl was added dropwise to acidify the pH test paper so that it became congo red, thereby obtaining a product precipitated as a solid. The precipitated product was filtered through a reduced pressure filter and purified by silica gel column chromatography using ethyl acetate to obtain a white solid (2.518 g). Yield: 27.93%

¹ H-NMR (400 MHz, acetone-d ₆ , in ppm): 7.27 (m, 2H,), 7.36 (m, 4H), 7.66 (d, H, J = 1.72 Hz), 7.68 (d, H, J = 1.79 Hz), 7.74 (d, 2H, J = 1.64 Hz), 7.95 (s, H), 7.97 (s, H), 8.10 (d, H, J = 8.37 Hz), 8.54 (d, H, J = 1.94 Hz).

FT-IR (KBr Pellet, cm ^-1 ): 3426 (OH stretch), 1700 (C=O stretch), 1566 (C=C aromatic stretch), 1452 (CN stretch), 1408 (CO stretch).

Example 1-4. Synthesis of iridium dimer

[Scheme 7]

In a nitrogen atmosphere reactor, iridium(III) chloride hydrate (1 g, 3.349 mmol), 1-phenylisoquinoline (1.581 g, 7.703 mmol) and 2-ethoxyethanol:water (3:1) (50 ml) were added to the mixture at room temperature. After stirring for 8 hours, it was refluxed for 24 hours. After the reaction was completed, the temperature was lowered to room temperature (25° C.), the mixture was precipitated in distilled water, filtered under reduced pressure, and dried in a vacuum oven. The precipitate was washed with ethanol and distilled water, and the washed product was washed with distilled water, filtered under reduced pressure, and dried. This washing process was repeated 3 times to obtain a red solid (4.316 g). Yield: 94.3%

¹ H-NMR (400 MHz, chloroform-d, in ppm): 6.01 (d, 4H, J = 7.57 Hz), 6.48 (t, 4H), 6.54 (d, 4H, J = 6.51), 6.79 (t, 4H), 7.72 (d, H, J = 1.41 Hz), 7.74 (t, 2H), 7.76 (d, H, J = 1.87 Hz), 7.79 (s, H), 7.80 (d, 6H, J = 7.49 Hz), 7.85 (s, H), 8.10 (d, 4H, J = 7.62 Hz), 8.95 (d, 4H, J = 8.49 Hz), 9.03 (d, 4H, J = 6.42 Hz).

FT-IR (KBr Pellet, cm ^-1 ): 3083 (CH stretch), 1658 (C=O stretch), 1574 (C=C aromatic stretch), 1487 (CN stretch), 1317 (CO stretch).

Example 1-5. Synthesis of compound 4

[Scheme 8]

In a nitrogen atmosphere reactor, add compound 3 (reaction ratio 2.5), iridium dimer (reaction ratio 1), sodium carbonate (reaction ratio 10), and 2-ethoxyethanol (25 ml) as a solvent to the extent that the solute is dissolved. It was stirred at °C for 24 hours. After the reaction was completed, the filtrate was filtered under reduced pressure, followed by washing with hexane and ethanol to obtain a red solid. Yield: 62.12%

¹ H-NMR (400 MHz, acetone-d ₆ , in ppm):: 6.31 (d, 1H, J = 7.81 Hz), 6.35 (d, 1H, J = 8.6 Hz), 6.49 (m, 1H), 6.59 (dd, 1H, J = 18.1 Hz, 1.21 Hz), 6.63 (d, 1H, J = 18.51 Hz), 6.69 (d, 2H, J = 7.21 Hz), 6.83 (t, 1H, J = 8.33 Hz), 6.92 (d, 1H, J = 1.58 Hz), 7.03 (t, 2H, J = 7.85 Hz), 7.15 (d, 1H, J = 1.53 Hz), 7.20 (d, 1H, J = 5.11 Hz), 7.28 ( d, 2H, J = 1.8 Hz), 7.36 (m, 1H), 7.43 (d, 1H, J = 1.68 Hz), 7.47 (d, 1H, J = 1.34 Hz), 7.51 (d, 2H, J = 5.68 Hz), 7.55 (d, 1H, J = 5.91 Hz), 7.7 (m, 3H), 7.75 (m, 2H), 7.86 (m, 1H), 7.91 (d, 1H, J = 8.28 Hz), 7.94 ( d, 1H, J = 2.08 Hz), 8.08 (d, 1H, J = 8.24 Hz), 8.15 (d, 1H, J = 8.00 Hz), 8.72 (d, 1H, J = 6.40 Hz), 8.85 (d, 1H, J = 7.56 Hz), 8.91 (m, 1H).

FT-IR (KBr Pellet, cm ^-1 ): 3044 (CH stretch), 1657 (C=O stretch), 1551 (C=C aromatic stretch), 1444 (CN stretch), 1389 (CO stretch).

Example 1-6. Synthesis of Iridium Copolymer

[Scheme 9]

For the synthesis of iridium copolymer, 2,7-dibromo-9,9'-dioctylfluoren (X), biphenyl-4,4'-diboronic acid (pinacol) ester (Y), and compound 4 (Z) When adjusting the composition ratio of, the molar ratio of each monomer is 50:50:0(M100), 0:50:50(N100), 45:50:5(M90N10), 25:50: 25 (M50N50), 12.5:50:37.5 (M25N75) and 37.5:50:12.5 (N75N25) were synthesized using the suzuki coupling reaction.

To explain this in more detail, 2,7-dibromo-9,9-n-octylfluorene and biphenyl-4,4'-diboronic acid bis(pinacol) ester and compound 4 (compound 4) were 2M purified in a nitrogen atmosphere. After dissolving in a mixture of potassium carbonate aqueous solution, Aliquat ^® 336, and toluene, it was refluxed at 100°C for 2 hours. When the temperature inside the reactor reached 100° C., Pd(PPh ₃ ) ₄ was added and reacted for 48 hours. After 48 hours, phenylboronic acid and bromobenzene were added as end-caps at intervals of 6 hours. Bromobenzene was added and reacted for an additional 6 hours, the reaction was terminated, and the mixture was precipitated in acetone to obtain a precipitate. The precipitate was filtered under reduced pressure and washed with distilled water and methanol to remove unreacted monomers, oligomers, and catalyst. The product obtained after removal of the catalyst was dissolved in chloroform and purified by reprecipitation in acetone.

<Example 2. Molecular Weight and Structure Analysis of Iridium Copolymer>

The synthesized polymer was measured for molecular weight by Shimadzu's GPC. In the measurement, chloroform was used as a solvent.

As a result of the measurement, as shown in Table 1, the molecular weights of M100 and M90N10 were measured, but the remaining copolymers had low solubility in organic solvents, so that the molecular weight could not be measured by GPC.

In addition, the structure was investigated by ¹ H-NMR and FT-IR spectroscopy. The solvent used for the ¹ H-NMR measurement was chloroform-d. All FT-IRs were measured by making KBr pellets. As a result of the measurement, it can be seen that as the content of compound 4 in the copolymer increases as shown in FIGS. 1 and 2, the intensity of absorption peaks of CN, C=O, and NH increase at 1400 cm ^-1 and 3400 cm ^-1 . have.

GPC data of soluble polymer Copolymer code Mn Mw PDI M100 11000 19500 1.77 M90N10 6700 7900 1.19

<Example 3. Light absorption and emission characteristics of iridium copolymer>

The light absorption properties of the synthesized polymer were measured in a solution state using chloroform as a solvent. The cell used for the measurement was a quartz cell. 3 is a UV-vis absorption spectrum measured in a chloroform solution state, and Table 2 shows the maximum wavelength of the UV-vis absorption spectrum measured in a solution of chloroform.

Looking at this in more detail, in the chloroform solution, M100 exhibited a maximum absorption wavelength at 365 nm because 2,7-dibromo-9,9-n-dioctyl-fluorene and biphenyl were combined. This can be explained that 2,7-dibromo-9,9-n-octylfluorene has a maximum absorption wavelength at 385 nm, and under this influence, the UV-vis absorption spectrum of M100 has a maximum absorption wavelength at 365 nm. In the case of N100, compound 4, an iridium compound, and iphenyl are combined. Compound 4, an iridium compound, had a maximum absorption wavelength at approximately 375 nm. N100 containing these structural units showed maximum absorption wavelength values at 350nm and 360nm. The two polymers mentioned above are homopolymers. In the case of the remaining three copolymers, looking at the UV-vis absorption spectrum, there are two monomers that can affect the absorption spectrum. Since the maximum absorption wavelength values of 2,7-dibromo-9,9-n-dioctyl-fluorene and compound 4 are similar, the maximum absorption wavelength values of M90N10, M50N50, and M25N75 differ in the composition ratio of the two units. appear.

The optical bandgap through the UV-vis absorption spectrum can be obtained by the following equation, and most of the optical bandgaps were obtained as 3.16-3.05 eV. It was found that there was no significant difference in the optical bandgap depending on the composition.

The luminescence properties of the synthesized polymer were measured in a solution state using chloroform, and the cell used for the measurement was a quartz cell. 4 is a PL spectrum measured in a chloroform solution state, and Table 3 shows the maximum wavelength of the PL spectrum measured in a solution state of chloroform.

In the present invention, a phosphorescent chromophore was applied to make a light emitting polymer, where 2,7-dibromo-9,9-n-dioctyl-fluorene was used as the fluorescent chromophore, and compound 4, which is an iridium compound, was used as the phosphorescent chromophore. ) Was used, and the maximum emission wavelength value of the phosphorescent chromophore used at this time was approximately 640 nm, and the maximum emission wavelength value of the fluorescent chromophore was approximately 415 nm.

In the case of M100 and M90N10, it is confirmed that they have the maximum emission wavelength values at 408 nm and 409 nm in the PL spectrum. From this, it can be seen that M100 and M90N10 do not emit red light. That is, this can be explained structurally, because first, in the case of M100, a phosphorescent chromophore compound (compound 4) was not used.

In the case of M100, 2,7-dibromo-9,9-n-dioctyl-fluorene and biphenyl consist of 1:1, and only 2,7-dibromo-9,9-n-dioctyl-fluorene, a fluorescent chromophore, is a chromophore. Since it was used, it is estimated that the maximum emission wavelength value of M100 was 409 nm.

In the case of M90N10, compound 4 was introduced. Looking at the composition ratio, the fluorescent chromophore, biphenyl, and phosphorescent chromophore have a composition ratio of 45:50:5, which means that the content of iridium is extremely small. Therefore, although the fluorescent and phosphorescent chromophores for phosphorescence emission were equipped, the composition ratio was not suitable. Although the phosphorescent chromophore emits red light, it emits blue light rather than red light because the content of 2,7-dibromo-9,9-n-dioctyl-fluorene emitting blue light is very high. As a result, the maximum emission wavelength value of M90N10 was 408 nm, and it was not red emission. On the other hand, when there is no or very little iridium content, M100 and M90N10 emit blue light.

UV-vis absorption of copolymers Copolymer code UV λ _max (nm) λ _onset (nm) Optical E _g (eV) M100 365 406 3.05 M90N10 365 393 3.16 M50N50 350, 360 396 3.13 M25N75 360 400 3.1 N100 350, 360 397 3.12

PL data of copolymers Copolymer code PL λ _max (nm) in CHCl ₃ solution M100 409 M90N10 408

<Example 4. Confirmation of mesogenicity of iridium copolymer>

As a result of confirming the liquid crystal phase of the polymer synthesized as shown in FIGS. 5 to 9 through POM image analysis, M100 is a thermally dissipating liquid crystal, M90N10, M50N50, and M25N75 are breast-like liquid crystals, and in the case of N100, the liquid crystal phase could not be confirmed.

That is, the heat dissipating liquid crystal M100 showed a nematic phase at 250°C. At around 280°C, T _i became an isotropic liquid.

Next, as a result of analyzing their characteristics using chloroform as a solvent to form a breast-like liquid crystal phase, M90N10 had excellent solubility due to the large amount of alkyl groups in its structure. Therefore, the liquid crystal phase was clearly confirmed by dissolving in a solvent. In the case of M50N50 and M25N75, the iridium content was increased more than that of M90N10, and the solubility was greatly decreased. Therefore, even when trying to check the liquid crystal phase by dissolving it with a solvent, the solubility was low due to the high content of iridium, so that the liquid crystal phase could not be properly identified. In the case of N100, structurally, there is no alkyl group at all. This means that most of the structure of N100 is composed of aromatic groups. If there are many structurally rigid groups, entropy decreases and solubility decreases. As a result, it was difficult to determine whether it was a parenchymal or breast-like.

In conclusion, M100 is a thermally dissipating liquid crystal and a nematic phase appeared at 250°C. In addition, M90N10 exhibited a lyotropic liquid crystal phase, M50N50 and M25N75 had low solubility, so it was not possible to properly determine whether or not to form a lyotropic liquid crystal phase, and N100 could not form a liquid crystal phase.

From the above results, it can be seen that when the mesogenic iridium copolymer of the present invention is prepared, the degree of luminescence can be controlled through the mixing ratio of the raw material compounds.

Claims (8)

A copolymer containing a mesogenic iridium complex represented by the following formula (1).
[Formula 1]

(The R1 and R2 are each independently selected from hydrogen or an alkyl group having 1 to 10 carbon atoms, and m and n are each independently an integer of 10 to 10000) Providing a biphenyl (biphenyl) derivative compound containing boron;
Providing a fluorene derivative compound; Providing a heterolaptic iridium complex;
Polymerizing the boron-containing biphenyl derivative compound, fluorene derivative compound, and heterolabtic iridium complex; And,
Capping the polymer end group with a phenyl derivative after the polymerization step;
A method for producing a copolymer comprising a mesogenic iridium complex represented by Formula 1 according to claim 1, characterized by comprising a. The method of claim 2,
The biphenyl (biphenyl) derivative compound containing boron is a method for producing a copolymer including a mesogenic iridium complex, characterized in that represented by the following formula (2).
[Formula 2]

The method of claim 2,
The fluorene derivative compound is a method for producing a copolymer containing a mesogenic iridium complex, characterized in that represented by the following formula (3).
[Formula 3]

(The R1 and R2 are each independently selected from hydrogen or an alkyl group having 1 to 10 carbon atoms) The method of claim 2,
The heterolabtic (heteroleptic) iridium complex is a method for producing a copolymer including a mesogenic iridium complex, characterized in that represented by the following formula (4).
[Formula 4]

(The X is selected from Cl, Br, and I) The method of claim 2,
The polymerization reaction is a method for producing a copolymer containing a mesogenic iridium complex, characterized in that the reaction is carried out under a palladium-based catalyst. The method of claim 2,
The phenyl derivative is a method of producing a copolymer including a mesogenic iridium complex, characterized in that selected from bromobenzene or phenylboronic acid. A lyotropic liquid crystal composition comprising the copolymer of claim 1.

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