TWI509058B - Liquid crystal compound, liquid crystal composition and liquid crystal display device - Google Patents

Description

Liquid crystal compound, liquid crystal composition, and liquid crystal display element

The present invention relates to a liquid crystal compound, and more particularly to a liquid crystal compound having high dielectric anisotropy and low rotational viscosity, a liquid crystal composition containing the liquid crystal compound, and a liquid crystal display element.

Liquid crystal displays have the advantages of light weight, power saving, no radiation and full color display, so they have become the most common display products. In recent years, with the continuous improvement of technology and the requirements for high resolution, high reaction rate and high image quality, liquid crystal displays have been twisted nematic (TN), super twisted nematic (STN). With the passive drive display mode such as bistable twisted nematic (BTN), it has developed into an active matrix liquid crystal display with a thin film transistor (TFT). With the demand of wide viewing angle technology, in-plane switching (IPS), fringe field switching (FFS), vertical alignment (VA) and polymer sustained alignment (PSA) The development and breakthrough of liquid crystal display methods are very important for the application and development of future panels.

For liquid crystal displays, what is needed is a dielectric constant anisotropy (Δε) and a low rotational viscosity (rotational). Viscosity, γ1), suitable refractive index, and a wide range of operating temperature liquid crystal media. In particular, when the liquid crystal medium has a high dielectric anisotropy, the threshold voltage (Vth) of the liquid crystal display device can be lowered; when the liquid crystal medium has a low rotational viscosity, the response can be accelerated. Speed; when the liquid crystal medium has a high clearing point, the application operating temperature range of the liquid crystal medium can be expanded.

The present invention provides a liquid crystal compound which can be applied to a liquid crystal composition to provide a liquid crystal composition having a high dielectric anisotropy, a low rotational viscosity, and a wide liquid crystal phase range, and the liquid crystal composition is used to produce a liquid crystal display. The component can make the liquid crystal display element have better display performance and quality.

The liquid crystal compound of the present invention is represented by Formula 1: Formula 1, wherein R ¹ is an alkyl group or an alkenyl group, one or more hydrogen atoms in R ¹ may be substituted by a fluorine atom, and one or a plurality of adjacent -CH ₂ - may be substituted by -O-, wherein R ¹ in one or more -CH ₂ - -O- unsubstituted substituent, the carbon number of R ¹ is 2 to 10, and when R ¹ in one or a plurality of non-adjacent -CH ₂ - is - When O-substituted, R ^{1 has} a carbon number of 2 to 10; R ² is an alkyl group having 1 to 10 carbon atoms; and A ¹ , A ² , A ³ and A ^{4 are} independently 1,4-cyclohexylene. Or 1,4-phenylene, wherein one or more hydrogen atoms on A ¹ to A ⁴ may be substituted by halogen; Z ¹ , Z ² and Z ^{3 are} independently a single bond, -C ₂ H ₄ -, - COO-, -OCO-, -CF ₂ O-, -OCF ₂ -, -C≡C- or -CH=CH-; and n, m are independently 1 or 0.

The liquid crystal composition of the present invention comprises a liquid crystal compound as described above.

The liquid crystal display element of the present invention comprises a liquid crystal compound as described above.

Based on the above, the present invention provides a liquid crystal compound and a liquid crystal composition comprising the liquid crystal compound and a liquid crystal display element, wherein the liquid crystal composition has high dielectric anisotropy, low rotational viscosity, wide liquid crystal phase range, and good acid resistance Heat resistance and UV resistance.

The above described features and advantages of the present invention will be more apparent from the following description.

In the present specification, the range represented by "a value to another value" is a schematic representation that avoids enumerating all the values in the range in the specification. Therefore, a particular numerical range is recited and is equivalent to the disclosure of any numerical value in the range of the value and the numerical range defined by any value in the numerical range, as the The smaller value range is the same. For example, the description of the "content of 10 to 80%" is equivalent to the disclosure of the "content of 20% to 40%", regardless of whether other values are listed in the specification.

Herein, if a group is not specifically indicated to be substituted, the group may represent a substituted or unsubstituted group. For example, "alkyl" can mean a substituted or unsubstituted alkyl group.

In this context, the structure of a compound is sometimes represented by a skeleton formula. This representation can omit carbon atoms, hydrogen atoms, and carbon-hydrogen bonds. Of course, if the atom or atomic group is clearly drawn in the structural formula, the person who prescribes it shall prevail.

One embodiment of the present invention provides a liquid crystal compound having high dielectric anisotropy, low rotational viscosity, wide liquid crystal phase range, and good acid resistance, heat resistance, and UV resistance.

The liquid crystal compound of the present embodiment is represented by the following formula 1: Formula 1, wherein the definitions of R ¹ , R ² , A ¹ , A ² , A ³ , A ⁴ , Z ¹ , Z ² , Z ³ , n and m will be described in detail below.

R ¹ is an alkyl or alkenyl group, one or more hydrogen atoms of R ¹ may be substituted with a fluorine atom, or a plurality of non-adjacent -CH ₂ - may be replaced by -O-, wherein R ¹ is wherein when When one or more -CH ₂ - is not substituted by -O-, R ^{1 has} a carbon number of 2 to 10, preferably a carbon number of 2 to 5, and when one or none of R ¹ is adjacent When -CH ₂ - is substituted by -O-, R ^{1 has} a carbon number of 2 to 10, and preferably has a carbon number of 2 to 5. That is, in the present embodiment, R ¹ may be a group, an alkyl group or an alkene in which one or more hydrogen atoms in an unsubstituted alkyl or alkenyl group, an alkyl group or an alkenyl group are substituted by a fluorine atom. One or a plurality of non-adjacent groups of -CH ₂ - are substituted by -O-, or one or more hydrogen atoms in the alkyl or alkenyl group are replaced by fluorine atoms and one or non-adjacent more -CH ₂ - replaced by -O- the group, and whether in R ¹ -CH ₂ - substituted with -O- whether, R ¹ is a carbon number of 2 to 10, carbon atoms is preferred 2 to 5. Further, the aforementioned alkyl group may be a linear or branched alkyl group, and the aforementioned alkenyl group may be a linear or branched alkenyl group.

In one embodiment, one or more hydrogen atoms in R ¹ are replaced by a fluorine atom.

In one embodiment, R ¹ is one or more non-adjacent -CH ₂ - replaced by -O-; e.g., R ¹ may be an alkoxy group, an alkenyl group or an ether group.

In one embodiment, R ¹ is an alkenyl group, wherein one or more hydrogen atoms may be substituted by a fluorine atom, and one of R ¹ or a plurality of non-adjacent-CH ₂ - is substituted by -O-; That is, R ¹ is a group containing both -O- and a double bond. For example, R ¹ is -OCHCF ₂ , -OCF ₂ CHCF ₂ , -OCHCHCH ₃ .

In one embodiment, R ^{1 is} selected from an alkyl, alkoxy, alkenyl, alkenyloxy or ether group having a carbon number of 2 to 10, preferably an alkyl group or an alkane having a carbon number of 2 to 5. An oxy, alkenyl, alkenyloxy or ether group in which one or more hydrogen atoms on R ¹ may be substituted by a fluorine atom.

In one embodiment, R ¹ is -OCHCF ₂ , -OCF ₂ CFCF ₂ or -OCH ₂ CF ₃ .

R ² is an alkyl group having 1 to 10 carbon atoms. In detail, R ² is a linear or branched alkyl group having a carbon number of 1 to 10, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl Base, pentyl, hexyl, heptyl, octyl, decyl or fluorenyl.

A ¹ , A ² , A ³ and A ^{4 are} independently 1,4-cyclohexylene or 1,4-phenylene, wherein one or more hydrogen atoms on A ¹ to A ⁴ may be substituted by halogen. In detail, one or more hydrogen atoms on the 1,4-cyclohexylene group and the 1,4-phenylene group may be substituted by a fluorine atom, a chlorine atom or a bromine atom.

In one embodiment, A ¹ , A ² , A ³ and A ^{4 are} independently selected from , and The group of people formed.

In one embodiment, A ¹ , A ² , A ³ and A ^{4 are} independently selected from and The group of people formed.

In one embodiment, A ¹ , A ² , A ³ and A ⁴ are .

Z ¹ , Z ² and Z ^{3 are} independently a single bond, -C ₂ H ₄ -, -COO-, -OCO-, -CF ₂ O-, -OCF ₂ -, -C≡C- or -CH=CH -. In one embodiment, Z ¹ , Z ² and Z ^{3 are} independently selected from the group consisting of a single bond and -CF ₂ O-.

n, m are independently 1 or 0. That is, the liquid crystal compound represented by Formula 1 has a structure of three to five rings. In one embodiment, n and m are both 0; that is, the liquid crystal compound represented by Formula 1 has three ring structures, and wherein The structure is directly connected to R ² .

Further, in one embodiment, the liquid crystal compound represented by Formula 1 is selected from the group consisting of compounds represented by the following Formula 1-a to Formula 1-d: Equation 1-a, Equation 1-b, Equation 1-c, and Formula 1-d, wherein the definitions of R ¹ and R ² in the formula 1-a to the formula 1-d have been explained above.

In one embodiment, the liquid crystal compound represented by Formula 1 is selected, for example, from the following liquid crystal compounds 1-a-1 to 1-a-3, 1-b-1 to 1-b-3, 1-c-1, and 1- The group consisting of d-1: 1-a-1, 1-a-2, 1-a-3, 1-b-1, 1-b-2, 1-b-3, 1-c-1, and 1-d-1.

Since the liquid crystal compound represented by Formula 1 has a skeleton The structure and R ^{1 have} a carbon number of 2 to 10, and thus have a high dielectric anisotropy, a low rotational viscosity, and a wide liquid crystal nematic phase range. Further, by adjusting different linking groups or substituents (for example, fluorine atoms), the liquid crystal compound represented by Formula 1 can further achieve the purpose of lowering the rotational viscosity while maintaining acid resistance, heat resistance, and UV resistance.

Another embodiment of the present invention provides a liquid crystal composition comprising, in addition to the liquid crystal compound represented by Formula 1, at least one selected from the group consisting of compounds represented by Formula 2: Formula 2 wherein R ³ is an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and in the aforementioned alkyl or alkenyl group, one or more hydrogen atoms may be substituted by a fluorine atom, one Or a plurality of non-adjacent -CH ₂ - may be substituted by -O-; R ⁴ is a halogen, an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and the aforementioned alkyl group or alkene In the group, one or more hydrogen atoms may be substituted by a fluorine atom, and one or a plurality of adjacent -CH ₂ - may be substituted by -O-; A ⁵ , A ⁶ and A ^{7 are} independently 1,4-stretched Cyclohexyl or 1,4-phenylene, wherein one or more hydrogen atoms on A ⁵ to A ⁷ may be substituted by halogen; Z ⁴ and Z ^{5 are} independently a single bond, -C ₂ H ₄ -, -COO -, -OCO-, -CF ₂ O-, -OCF ₂ -, -C≡C- or -CH=CH-; and o is 1 or 0.

In the present embodiment, the content of the liquid crystal compound represented by Formula 1 is 2 wt% to 50 wt%, preferably 2.5 wt% to 25 wt%, based on the total weight of the liquid crystal composition, and the content of the compound represented by Formula 2 is 1 wt. % to 99% by weight, preferably 50% by weight to 91% by weight.

In one embodiment, the compound represented by Formula 2 includes the following liquid crystal compounds 2-a to 2-c: 2-a; 2-b; 2-c.

Since the liquid crystal composition of the present embodiment contains the liquid crystal compound represented by Formula 1, it has high dielectric anisotropy, low rotational viscosity, wide liquid crystal phase range, and good acid resistance, heat resistance, and UV resistance.

Still another embodiment of the present invention provides a liquid crystal display element characterized by comprising the liquid crystal composition of any of the foregoing embodiments. Of course, the liquid crystal display element may also have other known members of the liquid crystal display element, such as a substrate, a polarizer, a color filter or an alignment film, and the like. The manufacturing method and constituent elements of the liquid crystal display element can be arbitrarily selected from the prior art except for the liquid crystal composition contained therein, and thus will not be described herein.

Since the liquid crystal display element of the present embodiment employs the liquid crystal composition containing the liquid crystal compound represented by Formula 1 described above, it has advantages of low threshold voltage and fast response speed, and is also suitable for use over a wide temperature range. Good display quality.

〔experiment〕

The invention will be described more specifically hereinafter with reference to the embodiments. Although the following experiments are described, the contents can be appropriately changed without exceeding the scope of the present invention. Use materials, their quantities and ratios, processing details, and process flow. Therefore, the invention should not be construed restrictively on the basis of the experiments described below.

Since the following examples and comparative examples use a plurality of liquid crystal compounds, for the sake of simplicity of the description, different liquid crystal compounds will be denoted by a combination of code numbers, wherein O represents an oxygen atom, and each structural unit represented by each code is arranged in a table. One.

<Synthesis method of liquid crystal compound> Synthesis Example 1

A method for synthesizing the liquid crystal compound 1-a-1 (2toPU-O1CF3) is shown below.

Synthesis of compound a1:

100 g of 1,1,1-trimethylolpropane, 132 g of diethyl carbonate (DEC), 0.25 g of potassium hydroxide and 10 ml of ethanol were placed in a 500 ml dry clean three-necked flask. Next, the mixture was stirred and heated to reflux for 2 hours. Thereafter, after evaporating the solvent under normal pressure at 150 ° C, the temperature was lowered to 120 ° C. Finally, distillation under reduced pressure was carried out to obtain Compound a1 (yield: 64.7%) as a colorless transparent liquid.

Synthesis of compound a2:

To a 2 L clean three-necked flask was added 82 g of compound a1, 111 g of pyridine and 400 ml of dichloromethane. Next, the mixture was stirred under a nitrogen atmosphere and cooled to 0 ° C to 5 ° C. The temperature control was carried out at 0 ° C to 5 ° C, and a solution consisting of 163 g of 4-bromobenzamide chloride and 200 ml of dichloromethane was added dropwise. After the addition was completed, the temperature was naturally raised and stirred overnight. Thereafter, 500 ml of water was added to the three-necked flask, and after stirring for 5 minutes, liquid separation and organic phase were carried out. Next, extract the aqueous phase with 100 ml of dichloromethane. The combined organic phases were washed twice with 100 ml of an aqueous solution of sodium chloride twice until the pH was near neutral. Thereafter, the organic phase was dried with 20 g of anhydrous sodium sulfate for 30 min, and then suction filtered. Next, the filtrate was subjected to gel column chromatography (the extract was petroleum ether: ethyl acetate = 9:1). The chromatographic solution was collected, concentrated, and recrystallized using 1 time of ethanol, and placed in a refrigerator. After 8 hours or more, it was taken out for suction filtration. Finally, a small amount of frozen ethanol was used to rinse to give Compound a2 as a white solid (actual yield: 145 g, yield: 68.7%, purity (measured by gas chromatograph GC): 98.109%, melting point (mp): 50.63 ° C ~ 52.56 ° C).

Synthesis of compound a3:

12 g of compound a2 and 90 ml of dichloromethane were added to a 250 ml dry clean three-necked flask. The mixture was stirred under nitrogen and cooled to 0 °C using liquid nitrogen. Temperature control At 0 ° C, 1.4 g of boron trifluoride diethyl ether was added dropwise, and after the completion of the dropwise addition, the temperature was controlled at 0 ° C and the reaction was continued for 30 min. Thereafter, the temperature was naturally raised to room temperature, and the reaction was continued for 4 hours. The completion point of the reaction was confirmed by thin layer chromatography (TLC), and when it was confirmed that the reaction was completed, the above mixture was added to diatomaceous earth for suction filtration. Next, the filtrate was concentrated under reduced pressure to give a dried material. The dried product was dissolved in 1 part by weight of dichloromethane, and mixed with 1 time weight of yttrium gum, followed by concentration under reduced pressure to obtain a dried product containing guar gum. Next, the dried product was subjected to chromatography in a column containing 3 to 4 times by weight of tannin (the extract was petroleum ether: ethyl acetate = 20:1, and then a total volume of 1% triethylamine was added. ). Finally, the chromatography solution was collected and concentrated to give Compound a3 (yield: 12 g, actual yield: 7 g, yield: 58%, mp: 93.7 ° C to 97.5 ° C) as a white solid.

Synthesis of compound a4:

40 g of 2,2,2-trifluoroethanol, 80 g of triethylamine and 160 ml of dichloromethane were placed in a 500 ml dry clean three-necked flask. The mixture was stirred under a nitrogen atmosphere, and after cooling to -5 ° C to 0 ° C, 75 g of p-toluenesulfonyl chloride was added in portions. Subsequently, the temperature was naturally raised to room temperature (20 ° C to 25 ° C), and reacted for 4 hours. Thereafter, 100 ml of water was added to the three-necked bottle and stirred for 5 minutes, and then the aqueous phase and the organic phase were separated. Next, the aqueous phase was extracted twice with 50 ml of dichloromethane, and the combined organic phases were washed twice with 50 ml of an aqueous solution of sodium chloride to near neutral. Thereafter, the organic phase was dried with 20 g of anhydrous sodium sulfate for 30 min, and then suction filtered. Next, the filtrate was concentrated under reduced pressure, and then hot-solved by adding 2 times by weight of ethanol, and placed in a refrigerator for 4 hours or more, and then taken out for suction filtration. Finally, it was rinsed with a small amount of frozen ethanol, and the above crystallization operation was repeated until a compound a4 was obtained as a white solid (theoretical yield: 101 g, actual yield: 68 g, yield: 67.3%, purity (measured by gas chromatography GC) Test): 99.976%).

Synthesis of compound a5:

To a 1 L clean three-necked flask was added 6 g of sodium hydride (60%) and 70 ml of N,N-dimethyl formamide (DMF). Then, after continuously stirring and lowering the temperature to -5 ° C to 0 ° C, a solution consisting of 120 ml of DMF and 30 g of 4-bromo-2,6-difluorophenol was added dropwise. And the temperature control is below 25 °C. After the completion of the dropwise addition, the temperature was raised to 90 ° C to 95 ° C under continuous stirring for 1 hour, and a solution consisting of 200 ml of DMF and 40 g of the compound a4 was added dropwise, and the temperature was raised to 110 ° C, and the temperature was controlled at this temperature. hour. Thereafter, the reaction solution was slowly poured into a beaker containing crushed ice to be hydrolyzed, 25 ml of hydrochloric acid was added to adjust the pH to neutrality, and then 100 ml of petroleum ether was added and stirred for 5 minutes, followed by liquid separation to obtain an aqueous phase and an organic phase. Next, extract the aqueous phase twice with 50 ml of petroleum ether, and use The combined organic phase was washed twice with 100 ml of an aqueous solution of sodium chloride until the pH was near neutral. Thereafter, the organic phase was dried with 20 g of anhydrous sodium sulfate for 30 min, and then suction filtered. Next, the filtrate was concentrated under reduced pressure, and then subjected to silica gel column chromatography (2 times column height of petroleum ether) twice at room temperature. Finally, the chromatographic solution was collected and concentrated to give the compound a5 as a colorless transparent liquid (theoretical yield: 41.7 g, actual yield: 26.5 g, yield: 63.5%, purity (measured by gas chromatograph GC): 96.8%).

Synthesis of compound a6:

13 g of magnesium turnings and 60 ml of diethyl ether were added to a 250 ml dry clean three-necked flask. Next, the foregoing mixture was stirred under a nitrogen atmosphere, and a small amount of ethyl bromide was added to initiate the reaction. Subsequently, the temperature was lowered to 0 ° C to 10 ° C, and a temperature-controlled solution of 12 g of the compound a5 and 30 ml of diethyl ether was added dropwise at this temperature. After the completion of the dropwise addition, the temperature was continuously controlled at 0 ° C to 10 ° C for 1 hour. Subsequently, the temperature was lowered to -70 ° C to -80 ° C, and 15.6 g of triisopropyl borate was added dropwise at this temperature. After the completion of the dropwise addition, the temperature was naturally raised to -20 ° C, and then 20 ml of a dilute aqueous hydrochloric acid solution was added to the three-necked flask, and after stirring for 5 minutes, the aqueous phase and the organic phase were separated. Next, the aqueous phase was extracted twice with 20 ml of ethyl acetate, and the combined organic phases were washed twice with 50 ml of aqueous sodium chloride. Thereafter, the organic phase was dried with 20 g of anhydrous sodium sulfate for 30 min, and then suction filtered. Finally, the filtrate was concentrated under reduced pressure to give Compound a6 (yield: 10.5 g, actual yield: 6.2 g, yield: 59%).

Synthesis of liquid crystal compound 1-a-1 (2toPU-O1CF3):

4 g of compound a3, 3.8 g of compound a6, 3.6 g of potassium carbonate, 0.1 g of tetrakis(triphenylphosphine)palladium 0.5 g of tetrabutylammonium bromide were added to a 100 ml dry clean three-necked flask. TBAB), 40 ml of tetrahydrofuran (THF) and 10 ml of water. Next, the mixture was stirred and heated under reflux (70 ° C to 80 ° C) for 4 hours, and then 50 ml of water was added to the three-necked flask, and the mixture was stirred for 5 minutes, followed by liquid separation to obtain an aqueous phase and an organic phase. Next, the aqueous phase was extracted twice with 30 ml of toluene, and the combined organic phases were washed twice with 50 ml of an aqueous solution of sodium chloride until the pH was near neutral. Thereafter, the organic phase was dried with 20 g of anhydrous sodium sulfate for 30 min, and then suction filtered. Next, the filtrate was concentrated under reduced pressure to give 6.2 g of dried material. The dried product was dissolved in 1 time by weight of methylene chloride, and mixed with 1 time weight of yttrium gum, followed by distillation under reduced pressure to obtain a dried product containing guar gum. Next, the dried product was subjected to chromatography in a column containing 3 to 4 times by weight of tannin (the extract was petroleum ether: ethyl acetate = 20:1, and then a total volume of 1% triethylamine was added. ). Finally, the chromatography liquid was collected and concentrated to give a liquid crystal compound 1-a-1 (2toPU-O1CF3) as a white solid (theoretical yield: 5.7 g, actual yield: 3.6 g, yield: 63.1%). GCMS: m/z = 430.2350 [M+]; ¹ H NMR (400 MHz, CDCl ₃ ): δ (ppm) 0.879 (t, 3H, J = 8 Hz), 1.320 (q, 2H, J = 8 Hz), 3.651 (s) , 2H), 4.105 (s, 6H), 6.255 (d, 1H, J = 12 Hz), 7.127 (d, 2H, J = 8.8 Hz), 7.463 (d, 2H, J = 8 Hz), 7.676 (d, 2H) , J = 8Hz).

Synthesis Example 2

A method for synthesizing the liquid crystal compound 1-a-2 (2toPU-O2F) is shown below.

5 g of diisopropylamine and 20 ml of THF were added to a 100 ml dry clean three-necked flask. Next, the mixture was stirred under a nitrogen atmosphere and cooled to -10 ° C to 0 ° C. The temperature was controlled at -10 ° C ~ 0 ° C, 13 ml of n-butyl lithium was added dropwise. After the completion of the dropwise addition, the temperature was controlled at -10 ° C to 0 ° C and the reaction was continued for 1 hour to obtain the LDA reagent used in the subsequent step. Separately, 3.6 g of the liquid crystal compound 1-a-1 and 20 ml of THF were placed in another 100 ml of a dry clean three-necked flask. Next, the mixture was stirred under a nitrogen atmosphere, and after cooling to -70 ° C to -80 ° C, the LDA reagent obtained above was added dropwise. After the completion of the dropwise addition, the temperature was controlled at -70 ° C to -80 ° C for 2 hours, and then 20 ml of water was added to the three-necked flask, and after stirring for 5 minutes, the aqueous phase and the organic phase were separated. Next, the aqueous phase was extracted twice with 20 ml of ethyl acetate, and the combined organic phases were washed twice with 50 ml of aqueous sodium chloride. Thereafter, the organic phase was dried with 20 g of anhydrous sodium sulfate for 30 min, and then suction filtered. Next, the filtrate was concentrated under reduced pressure to give a dried material. The dried product was dissolved in 1 time by weight of methylene chloride, and mixed with 1 time weight of yttrium gum, followed by distillation under reduced pressure to obtain a dried product containing guar gum. Next, the dried product was subjected to chromatography in a column packed with 4 to 5 times by weight of tannin (the extract was petroleum ether: ethyl acetate = 20:1, and then a total volume of 1% triethylamine was added. ). Finally, the chromatography liquid was collected and concentrated to give a liquid crystal compound 1-a-2 (2toPU-O2F) as a white solid (actual yield: 2.7 g, yield: 75%, mp: 169.16 ° C to 169.94 ° C). GCMS: m/z = 410.4606 [M] ⁺ ; ¹ H NMR (400 MHz, CDCl ₃ ): δ (ppm) 0.879 (t, 3H, J = 8 Hz), 1.320 (q, 2H, J = 8 Hz), 4.105 ( s, 6H), 6.255 (d, 1H, J = 12 Hz), 7.127 (d, 2H, J = 8.8 Hz), 7.463 (d, 2H, J = 8 Hz), 7.766 (d, 2H, J = 8 Hz).

Synthesis Example 3

The synthesis method of preparing liquid crystal compound 1-b-1 (2toUQU-O1CF3) is as follows Shown.

Synthesis of compound b1:

28.8g of magnesium turnings, 50ml of THF and a small amount of 3,5-difluorobromobenzene were added to a 2L dry clean three-necked flask. After stirring, 193 g of 3,5-difluorobromobenzene and 600 ml of THF were added dropwise. The solution is composed and maintained at reflux (about 78 ° C). After the completion of the dropwise addition, the reflux reaction was continued for 1 hour. Next, after the nitrogen protection was lowered to room temperature, 300 ml of THF was further added, and the temperature was further lowered to -40 ° C to -50 ° C. When the temperature is maintained at -40 ° C ~ -50 ° C, carbon dioxide gas is introduced, after the air is no longer heated (about 1 hour), and then ventilated for 30 minutes, the ventilation is stopped, and the temperature is naturally returned to -20 ° C. Thereafter, the reaction solution was slowly poured into a beaker containing crushed ice and hydrochloric acid for acid hydrolysis, and after stirring for 5 minutes, liquid separation and an organic phase were obtained. Next, the aqueous phase was extracted twice with 100 ml of ethyl acetate, and the combined organic phases were washed twice with 100 ml of aqueous sodium chloride. Thereafter, the organic phase was dried with 30 g of anhydrous sodium sulfate for 30 min, and then suction filtered. Next, the filtrate was concentrated under reduced pressure, and then 2 times by weight of petroleum ether and 1 time by weight of toluene were added for hot solution crystallization. Crystallization completed After suction filtration, it was rinsed with a small amount of frozen petroleum ether to give compound b1 as a pale yellow solid (theoretical yield: 158 g, actual yield: 93 g, yield: 58.8%, mp: 121.11 ° C to 121.96 ° C).

Synthesis of compound b2:

70 g of 3,5-difluorobenzoic acid, 105 g of hydrazine chloride, 250 ml of toluene and a few drops of DMF were added to a 1 L dry clean three-necked flask, and stirring was started, followed by heating under reflux for 4 hours. After that, the heating is stopped and the temperature is lowered to no reflux. Next, the reaction liquid was subjected to distillation under reduced pressure to give Compound b2 (yield: 78.5 g, actual yield: 68 g, yield: 86.6%).

Synthesis of compound b4:

43 g of the compound b3 was added to a 1 L dry clean three-necked flask (for the synthesis, please refer to the aforementioned compound a1, which will not be described again), 70 g of pyridine and 200 ml of dichloromethane. Next, the mixture was stirred under a nitrogen atmosphere and cooled to 0 ° C to 5 ° C. A solution consisting of 68 g of compound b2 and 100 ml of dichloromethane was added dropwise at a temperature controlled from 0 ° C to 5 ° C. After the addition was completed, the temperature was naturally raised and stirred overnight. Thereafter, 100 ml of water was added to the three-necked flask and stirred for 5 minutes, followed by liquid separation to obtain an aqueous phase and an organic phase. Next, the aqueous phase was extracted twice with 100 ml of dichloromethane, and the combined organic phases were washed twice with 100 ml of an aqueous solution of sodium chloride until the pH was near neutral. Thereafter, the organic phase was dried with 20 g of anhydrous sodium sulfate for 30 min, and then suction filtered. Next, the filtrate was subjected to a gel column chromatography (the extract was petroleum ether: ethyl acetate = 9:1). The chromatographic solution was collected and concentrated to give compound a4 as a pale yellow liquid (theoretical yield: 94.8 g, Actual yield: 58 g, yield: 61.2%, purity (measured by gas chromatograph GC): 95.799%).

Synthesis of compound b5:

Into a 500 ml dry clean three-necked flask, 27 g of compound b4 and 300 ml of dichloromethane were added. Next, the mixture was stirred under a nitrogen atmosphere and cooled to 0 ° C using liquid nitrogen. Temperature control At 0 ° C, 3.7 g of boron trifluoride etherate was added dropwise, and after the completion of the dropwise addition, the temperature was controlled at 0 ° C and the reaction was continued for 30 min. Thereafter, the temperature was naturally raised to room temperature, and the reaction was continued for 4 hours. The completion point of the reaction was confirmed by TLC, and when it was confirmed that the reaction was completed, the mixture was added to 10.6 g of triethylamine and stirred for 1 hour. Thereafter, the diatomaceous earth was added for suction filtration. Next, the filtrate was concentrated under reduced pressure, and then subjected to a gel column chromatography (the extract was 2 times column height of petroleum ether and 2 times column height of ethyl acetate). Subsequently, the chromatography solution was collected, concentrated, and recrystallized using a 2-fold amount of ethanol, and placed in a refrigerator for 6 hours or more, and then taken out for suction filtration. Finally, a small amount of frozen ethanol was used for rinsing to give compound b5 as a white solid (theoretical yield: 27 g, actual yield: 16.8 g, yield: 62.2%, purity (measured by gas chromatograph GC): 99.031% ).

Synthesis method of compound b6:

To a 500 ml dry clean three-necked flask was added 15.4 g of compound b5 and 160 ml of THF. Next, the mixture was stirred under a nitrogen atmosphere, and after cooling to -70 ° C to -80 ° C, 32 ml of n-butyllithium was added dropwise. After completion of the dropwise addition, the reaction was continued at -70 ° C to -80 ° C for 1 hour, and 38.6 g of a difluorodibromomethane solution (55.5%) was added dropwise. After the completion of the dropwise addition, the temperature was naturally raised to -30 ° C, and the reaction liquid was slowly poured into a water-containing beaker for hydrolysis, and then 50 ml of ethyl acetate was added and stirred for 5 minutes, and then the liquid phase and the organic phase were separated. Next, the aqueous phase was extracted twice with 50 ml of ethyl acetate, and the combined organic phases were washed with 50 ml of an aqueous sodium chloride solution and the pH was nearly neutral. Thereafter, the organic phase was dried with 20 g of anhydrous sodium sulfate for 30 min, and then suction filtered. Next, the filtrate is subjected to gel column chromatography (the extract is stone) Oleic ether: ethyl acetate = 95:5), chromatography was collected and concentrated to give compound b6 (yield: 23 g, actual yield: 22 g, yield: 95.6%).

Synthesis of liquid crystal compound 1-b-1 (2toUQU-O1CF3):

After adding 150 ml of water to a 500 ml dry clean three-necked flask, stirring was started and the temperature was raised to 50 ° C by heating. Next, 9.6 g of 1-trifluoroethoxy 2,6-difluorophenol, 12 g of potassium carbonate, and 3.4 g of TBAB were added to the three-necked flask, and the mixture was further heated to 80 ° C, and 22.5 g of the compound b6 was added. After that, the temperature was again raised to about 100 ° C and refluxed. After the reaction was continued for 6 hours, the temperature was then lowered to room temperature, and 50 ml of ethyl acetate was added to the three-necked flask. After stirring for 5 minutes, the aqueous phase was separated and organic. phase. Next, the aqueous phase was extracted twice with 20 ml of ethyl acetate, and the combined organic phases were washed twice with 50 ml of aqueous sodium chloride. Thereafter, the organic phase was dried with 20 g of anhydrous sodium sulfate for 30 min, and then suction filtered. Next, the filtrate was concentrated under reduced pressure, and then subjected to chromatography in a column containing 3 to 4 times by weight of tannin (the extract was petroleum ether: ethyl acetate = 3:1, and then added to the total volume of 1%). Triethylamine). Subsequently, the chromatography solution was collected, concentrated, and recrystallized using a 2-fold amount of ethanol, and placed in a refrigerator for 6 hours or more, and then taken out for suction filtration. Finally, it was rinsed with a small amount of cold ethanol to obtain a liquid crystal compound 1-b-1 (2toUQU-O1CF3) as a white solid (theoretical yield: 17.4 g, actual yield: 11.6 g, yield: 66.6%, purity (in the gas phase) Chromatography GC for measurement): 98.9%, mp: 93.12 ° C ~ 94.31 ° C). GCMS: m/z = 532.2276 [M] ⁺ ; ¹ H NMR (400 MHz, CDCl ₃ ): δ (ppm) 0.864 (t, 3H, J = 8 Hz), 1.328 (q, 2H, J = 8 Hz), 3.618 ( q, 2H, J = 11.2 Hz), 4.027 (s, 6H), 6.868 (d, 2H, J = 8 Hz), 7.655 (d, 2H, J = 8 Hz).

Synthesis Example 4

The synthesis method for preparing the liquid crystal compound 1-b-2 (2toUQU-O2F) is shown below.

20 g of diisopropylamine and 100 ml of THF were added to a 250 ml dry clean three-necked flask. Next, the mixture was stirred under a nitrogen atmosphere and cooled to -10 ° C to 0 ° C. Control temperature at -10 ° C ~ 0 ° C, add 53ml of n-butyl lithium, and after the completion of the addition, still control the temperature at -10 ° C ~ 0 ° C for 1 hour, in order to get used in the next step LDA reagent. Separately, 7 g of the liquid crystal compound 1-b-1 and 100 ml of THF were placed in another 500 ml dry clean three-necked flask. Next, the mixture was stirred under a nitrogen atmosphere, and after cooling to -70 ° C to -80 ° C, the LDA reagent obtained above was added dropwise. After the temperature was controlled at -70 ° C to -80 ° C for 2 hours, 20 ml of water was added to the three-necked flask, and after stirring for 5 minutes, the aqueous phase and the organic phase were separated. Next, the aqueous phase was extracted twice with 20 ml of ethyl acetate, and the combined organic phases were washed twice with 50 ml of aqueous sodium chloride. Thereafter, the organic phase was dried with 20 g of anhydrous sodium sulfate for 30 min, and then suction filtered. Next, the filtrate was concentrated under reduced pressure, and then subjected to chromatography in a column packed with 4 to 5 times by weight of tannin (the extract was petroleum ether: ethyl acetate = 3:1, and then added to the total volume of 1%). Triethylamine). Finally, the chromatographic solution was collected, concentrated, and recrystallized using twice the amount of ethanol to obtain a 1-b-2 liquid crystal compound (2toUQU-O2F) as a white solid (theoretical yield: 6.7 g, actual yield: 5 g, yield Rate: 74.6%, purity (measured by gas chromatograph GC): 98.9%, mp: 66.69 ° C ~ 67.53 ° C). GCMS: m/z = 512.1960 [M] ⁺ ; ¹ H NMR (400 MHz, CDCl ₃ ): δ (ppm) 0.868 (t, 3H, J = 8 Hz), 1.330 (q, 2H, J = 8 Hz), 4.429 ( s, 6H), 6.173 (d, 1H, J = 12 Hz), 6.873 (d, 2H, J = 8 Hz), 7.571 (d, 2H, J = 8 Hz).

As described above, the synthesis methods of the liquid crystal compounds 1-a-1, 1-a-2, 1-b-1, and 1-b-2 are described only by the synthesis examples 1 to 4, but those skilled in the art have synthesized according to the above. The synthesis of the liquid crystal compounds 1-a-3, 1-b-3, 1-c-1, 1-d-1 and liquid crystal compound 3 can be understood from the contents disclosed in the examples 1 to 4.

<Preparation and Properties Test of Liquid Crystal Composition> Example 1 to Example 9 and Comparative Example

Liquid crystal compound 1-a-1 to liquid crystal compound 1-a-3, liquid crystal compound 1-b-1 to liquid crystal compound 1-b-3, liquid crystal compound 1-c in the ratio (% by weight) shown in Table 2 -1, liquid crystal compound 1-d-1 and liquid crystal compound 3 were mixed with a mother liquid (composed of 2CCGF, 3CCGF and 5CCGF in a weight ratio of 1:1:1), respectively, thereby preparing liquid crystals of Examples 1 to 8. The liquid crystal composition of the composition and the comparative example; Example 9 was prepared according to the components shown in Table 4 and the ratio of each component.

<Property Test>

Next, the liquid crystal composition of Examples 1 to 9 and the liquid crystal composition of the comparative example were respectively subjected to a clearing point (Tni), a dielectric anisotropy (Δε), a rotational viscosity (γ1), and an optical anisotropy. The measurement of (Δn), wherein the measurement results of Examples 1 to 8 are described in Table 2, and the measurement results of Example 9 are shown in Table 4; the properties of the liquid crystal compound are derived from Examples 1 to 8. And recorded in Table 3 in. The above properties of the liquid crystal compound and the liquid crystal composition were measured by the following methods, respectively.

Clarification point (Tni, unit: °C):

Using a differential scanning calorimeter (DSC; manufacturer: TA; model: Q200), the liquid crystal compound or liquid crystal composition was placed in an aluminum pan with a scale of 0.5 mg to 10 mg, and the phase change temperature test was performed by DSC after the aluminum pan was pressed. That is, the phase change temperature is obtained by the endothermic peak of the liquid crystal compound or the liquid crystal composition due to the phase change and the starting point of the exothermic peak. Since the liquid crystal compound or the liquid crystal composition is a nematic phase, an endothermic peak which changes from a nematic phase to a liquid phase appears on the spectrum which is raised from room temperature, and the temperature of the clearing point can be read.

Dielectric anisotropy (△ε):

The liquid crystal composition to be tested was placed in a liquid crystal cell, and a voltage of 0 V to 20 V was applied to the liquid crystal cell at a temperature of 25 ° C, and a capacitance-to-voltage curve (C-V curve) was measured. In the CV curve, both the high voltage region and the low voltage region will be horizontal. The capacitor C⊥ is read in the low voltage region and the capacitor C∥ is read in the high voltage region, and can be converted to C by C⊥ and C∥ by the formula. ⊥, ε∥, dielectric anisotropy (Δε) = ε ∥ - ε ⊥.

Further, after Δε of each liquid crystal composition is obtained, the corresponding Δε of the liquid crystal compound to be tested is obtained by the known Δε of the mother liquid and by extrapolation.

Optical anisotropy (△n):

Each liquid crystal composition was measured by an Abbe refractometer (manufacturer: ATAGO; model: DR-M2) on which a polarizing plate was attached to one eyepiece. First, the alignment liquid is brushed in a single direction on the main surface of the Abbe refractometer, and the alignment is wiped in the same direction with a dust-free cloth, and then a small amount of the liquid crystal composition to be tested is dropped on the main crucible at the test temperature. Optical anisotropy at 25 ° C using a filter with a wavelength of 589 nm Sexual measurement. When the polarizing direction is parallel to the wiping direction, the measured refractive index is n∥; when the polarizing direction is perpendicular to the wiping direction, the measured refractive index is n⊥; optical anisotropy (Δn)=n∥-n⊥ .

Further, after obtaining Δn measured by each liquid crystal composition, the corresponding Δn of the liquid crystal compound to be tested is obtained by the known Δn of the mother liquid and by extrapolation.

Rotational viscosity (γ1, unit: mPa.s):

After the dielectric anisotropy (Δε) is measured as described above, the soft body can be converted from the rotational viscosity (γ1) by the Δε value.

Further, after obtaining γ1 measured by each liquid crystal composition, the corresponding γ1 of the liquid crystal compound to be tested is obtained by the known γ1 of the mother liquid and by extrapolation.

As can be seen from the above Table 3, the liquid crystal compounds 1-a-1 to 1-d-1 have dielectric anisotropy in accordance with the industrial requirements (range 19.2 to 49.8), and thus it is expected to adopt the formula 1 according to the present invention. The liquid crystal display element of the liquid crystal compound can have power saving characteristics. In addition, the liquid crystal compounds 1-a-1 to 1-d-1 have a low rotational viscosity as compared with the liquid crystal compound 3 of the comparative example, whereby it is expected that the liquid crystal display element employs the liquid crystal according to the formula 1 of the present invention. Compounds can reduce response time and response speed can be increased. In addition, the liquid crystal compounds 1-a-1 to 1-d-1 have a high clearing point as compared with the liquid crystal compound 3 of the comparative example, which indicates that it is expected that the liquid crystal compound according to the formula 1 of the present invention can be applied to a wider range. In the temperature range, thereby enhancing the application value of the liquid crystal display element.

The present invention has been disclosed in the above embodiments, but it is not intended to limit the invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

Claims (8)

A liquid crystal compound represented by Formula 1: And wherein R ¹ is a plurality of -CH ₂ -substituted or O-substituted alkenyl groups having 2 to 10 carbon atoms, or an ether group having 2 to 10 carbon atoms, wherein R ¹ is One or more hydrogen atoms may be substituted by a fluorine atom; R ² is an alkyl group having 1 to 10 carbon atoms; A ¹ , A ² , A ³ and A ^{4 are} independently 1,4-cyclohexylene or 1,4 a phenyl group in which one or more hydrogen atoms on A ¹ to A ⁴ may be substituted by halogen; Z ¹ , Z ² and Z ^{3 are} independently a single bond, -C ₂ H ₄ -, -COO-, - OCO-, -CF ₂ O-, -OCF ₂ -, -C≡C- or -CH=CH-; and n, m are independently 1 or 0. The liquid crystalline compound according to claim 1, wherein R ¹ is -OCHCF ₂ or -OCF ₂ CFCF ₂ . The liquid crystalline compound according to claim 1, wherein A ¹ , A ² , A ³ and A ^{4 are} independently selected from the group consisting of , and The group of people formed. The liquid crystalline compound according to claim 1, wherein Z ¹ , Z ² and Z ^{3 are} independently selected from the group consisting of a single bond and -CF ₂ O-. The liquid crystal compound according to claim 1, which is selected from the group consisting of compounds represented by the following formula 1-a to formula 1-d: ,as well as And wherein R ¹ is a plurality of -CH ₂ -substituted or O-substituted alkenyl groups having 2 to 10 carbon atoms, or an ether group having 2 to 10 carbon atoms, wherein R ¹ is One or more hydrogen atoms may be substituted by a fluorine atom; and R ² is an alkyl group having a carbon number of 1 to 10. A liquid crystal composition comprising the liquid crystal compound according to any one of claims 1 to 5. The liquid crystal composition according to claim 6, further comprising at least one selected from the group consisting of compounds represented by Formula 2: Wherein R ³ is an alkyl group having a carbon number of 1 to 10 or an alkenyl group having a carbon number of 2 to 10, and in the aforementioned alkyl or alkenyl group, one or more hydrogen atoms may be substituted by a fluorine atom, one or not The adjacent plurality of -CH ₂ - may be substituted by -O-; R ⁴ is a halogen, an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and is in the aforementioned alkyl or alkenyl group. One or more hydrogen atoms may be substituted by a fluorine atom, and one or a plurality of adjacent -CH ₂ - may be substituted by -O-; A ⁵ , A ⁶ and A ^{7 are} independently 1,4-cyclohexylene Or 1,4-phenylene, wherein one or more hydrogen atoms on A ⁵ to A ⁷ may be substituted by halogen; Z ⁴ and Z ^{5 are} independently a single bond, -C ₂ H ₄ -, -COO-, -OCO-, -CF ₂ O-, -OCF ₂ -, -C≡C- or -CH=CH-; and o is 1 or 0. A liquid crystal display element comprising the liquid crystal compound according to any one of claims 1 to 5.