TWI798860B - Liquid crystal compound with negative dielectric anisotropy, liquid crystal composition, liquid crystal display device - Google Patents

Abstract

The invention relates to a liquid crystal compound, a liquid crystal composition and a liquid crystal display device with negative dielectric anisotropy. The liquid crystal compound has a small response index value on the basis of maintaining a certain level of negative dielectric constant and thus has a faster response time.

Description

Liquid crystal compound with negative dielectric anisotropy, liquid crystal composition, liquid crystal display device

The invention relates to the field of liquid crystal display materials, in particular to a liquid crystal compound with negative dielectric anisotropy, a liquid crystal composition and a liquid crystal display device.

At present, the application range of liquid crystal compounds is expanding more and more widely, and it can be applied to various types of displays, electro-optic devices, sensors, and the like. There are various types of liquid crystal compounds used in the above-mentioned display fields, among which nematic liquid crystals are most widely used. Nematic liquid crystals have been used in passive TN, STN matrix displays and systems with TFT active matrix.

For the application field of thin film transistor technology (TFT-LCD), although the market has been huge in recent years and the technology has gradually matured, people's requirements for display technology are also constantly improving, especially in achieving fast response and reducing driving voltage to reduce power consumption etc. As one of the important optoelectronic materials of liquid crystal display, liquid crystal material plays an important role in improving the performance of liquid crystal display.

With the continuous development of TFT-LCD, the wide viewing angle mode has become the goal pursued by the industry. At present, the mainstream wide viewing angle technology mainly adopts display types such as VA vertical orientation, IPS in-plane switching and FFS fringe field switching. For these display modes, liquid crystal media with negative dielectric anisotropy are widely used. The demands on the response time of the liquid-crystalline media used in these modes are increasingly higher. However, the response time of liquid crystal media is affected by multiple factors such as viscosity, clearing point T _NI (°C), elastic coefficient, and refractive index. How to obtain liquid crystal compounds with improved response time under the combined effects of these factors is an urgent problem to be solved in this field. one.

The present invention aims at the problems existing in the above-mentioned prior art. After in-depth research, it is found that the core structure of dibenzothiophene or dibenzofuran shown in the formula I of the present invention is used, and the dibenzothiophene or dibenzofuran is used as the core structure through the linking group. The two sides of thiophene or dibenzofuran are bonded with an equal number of cyclic groups such as cyclohexyl, aromatic ring, heteroaryl and other liquid crystal compounds, which can obtain an improved dielectric constant while maintaining a certain level of negative dielectric constant. The novel liquid crystal compound of the response time of , thus completed the present invention.

For liquid crystal media, according to different display modes, the response time of liquid crystal media is related to G1/K ₁₁ or G1/K ₃₃ . Further, the inventors of the present invention found that, in addition to G1, K ₁₁ , K ₃₃ and other factors, the response time of the liquid crystal medium is also related to the clearing point T _NI (°C) and the refractive index Δn, specifically, in VA (vertical alignment , vertical alignment) or PS-VA (Polymer stabilized vertical alignment, polymer stabilized vertical alignment) mode, the response time of the liquid crystal medium is related to the value of G1/(K ₃₃ *△n*△n*T _NI ), while in FFS (Fringe Field Switching, fringe field switching), IPS (In-Plane Switching, plane switching), PS-FFS (Polymer stabilized Fringe Field Switching, polymer stabilized fringe field switching), PS-IPS (Polymer stabilized In-Plane Switching , polymer stabilized plane switching) and other modes, the response time of the liquid crystal medium is related to the value of G1/(K ₁₁ *△n*△n*T _NI ). In the present application, the values of G1/(K ₃₃ *Δn*Δn*T _NI ) and G1/(K ₁₁ *Δn*Δn*T _NI ) are referred to as response index values. The smaller the aforementioned response index value, the faster the response time of the liquid crystal medium. The liquid crystal compound with negative dielectric anisotropy of the present invention has a small response index value and thus an improved response time on the basis of maintaining a certain level of negative dielectric constant.

The present invention includes the following technical solutions: On the one hand, the present invention provides a liquid crystal compound with negative dielectric anisotropy, and the compound has a structure shown in the following formula I:

、

各自獨立地選自下述的基團組成的組：

Z₁、Z₂各自獨立地表示-C₂H₂-、-C₂H₄-、-C₂H₂CH₂O-、-OCH₂C₂H₂-、-CH₂O-、-OCH₂-、-C₂H₂CH₂S-、-SCH₂C₂H₂-、-CH₂S-、-SCH₂-、-O-、-S-、-CF₂O-、-OCF₂-、-C≡C-、-OOC-、或者-COO-、當Z₁、Z₂表示-CH₂O-、-C₂H₂-、-C₂H₄-、-C₂H₂CH₂O-、或者-OCH₂C₂H₂-時，任意H任選被F取代；X表示-O-、或、-S-；n表示1、2或者3。 In Formula I, R ₁ and R ₂ each independently represent a hydrogen atom, C1~C8 straight chain alkyl, C1~C8 straight chain alkoxy, C2~C8 straight chain alkenyl, C2~C8 straight chain Alkenyloxy, wherein one or two non-adjacent -CH ₂ -s are optionally substituted by -O-, and any H is optionally substituted by an F atom;

,

each independently selected from the group consisting of the following groups:

Z ₁ and Z ₂ each independently represent -C ₂ H ₂ -, -C ₂ H ₄ -, -C ₂ H ₂ CH ₂ O-, -OCH ₂ C ₂ H ₂ -, -CH ₂ O-, -OCH ₂ -, -C ₂ H ₂ CH ₂ S-, -SCH ₂ C ₂ H ₂ -, -CH ₂ S-, -SCH ₂ -, -O-, -S-, -CF ₂ O-, -OCF ₂ -, -C≡C-, -OOC-, or -COO-, when Z ₁ and Z ₂ represent -CH ₂ O-, -C ₂ H ₂ -, -C ₂ H ₄ -, -C ₂ H ₂ CH ₂ O-, or -OCH ₂ C ₂ H ₂ -, any H is optionally substituted by F; X represents -O-, or, -S-; n represents 1, 2 or 3.

Another aspect of the present invention provides a liquid crystal composition, which contains the aforementioned liquid crystal compound with negative dielectric anisotropy of the present invention.

Still another aspect of the present invention provides a liquid crystal display device, which contains the aforementioned liquid crystal compound with negative dielectric anisotropy of the present invention or the aforementioned liquid crystal composition of the present invention.

Compared with the prior art, the liquid crystal compound with negative dielectric anisotropy of the present invention has a small response index value on the basis of maintaining a certain level of negative dielectric constant and thus has a faster response time. By using the liquid crystal compound with negative dielectric anisotropy of the present invention in the liquid crystal composition of the present invention, and containing the liquid crystal composition using the liquid crystal compound of the present invention in the liquid crystal display device of the present invention, the display device can be made Response time is faster.

Fig. 1 is the mass spectrum of the compound COBOIC-3-3 prepared in Example 1 of the present invention.

Fig. 2 is the 1H nuclear magnetic resonance spectrum of the compound COBOIC-3-3 prepared in Example 1 of the present invention.

The present invention will be described below in combination with specific embodiments. It should be noted that the following examples are examples of the present invention, and are only used to illustrate the present invention, not to limit the present invention. Other combinations and various modifications within the concept of the present invention can be made without departing from the spirit or scope of the present invention.

[Liquid Crystal Compounds with Negative Dielectric Anisotropy]

The liquid crystal compound with negative dielectric anisotropy of the present invention has the structure shown in the following formula I:

、

各自獨立地選自下述的基團組成的組：

Z₁、Z₂各自獨立地表示-C₂H₂-、-C₂H₄-、-C₂H₂CH₂O-、-OCH₂C₂H₂-、-CH₂O-、-OCH₂-、-C₂H₂CH₂S-、-SCH₂C₂H₂-、-CH₂S-、-SCH₂-、-O-、-S-、-CF₂O-、-OCF₂-、-C≡C-、-OOC-或者-COO-，當Z₁、Z₂表示-CH₂O-、-C₂H₂-、-C₂H₄-、-C₂H₂CH₂O-、或者-OCH₂C₂H₂-時，其中任意H任選被F取代；X表示-O-、或者、-S-；n表示1、2或3。 In formula I, R ₁ and R ₂ each independently represent a hydrogen atom, C1~C8 straight chain alkyl, C1~C8 straight chain alkoxy, C2~C8 straight chain alkenyl, or C2~C8 straight chain Alkenyloxy, wherein one or two non-adjacent -CH ₂ -s are optionally substituted by -O-, and any H is optionally substituted by an F atom;

,

each independently selected from the group consisting of the following groups:

Z ₁ and Z ₂ each independently represent -C ₂ H ₂ -, -C ₂ H ₄ -, -C ₂ H ₂ CH ₂ O-, -OCH ₂ C ₂ H ₂ -, -CH ₂ O-, -OCH ₂ -, -C ₂ H ₂ CH ₂ S-, -SCH ₂ C ₂ H ₂ -, -CH ₂ S-, -SCH ₂ -, -O-, -S-, -CF ₂ O-, -OCF ₂ -, -C≡C-, -OOC- or -COO-, when Z ₁ and Z ₂ represent -CH ₂ O-, -C ₂ H ₂ -, -C ₂ H ₄ -, -C ₂ H ₂ CH ₂ O-, or -OCH ₂ C ₂ H ₂ -, wherein any H is optionally substituted by F; X represents -O-, or, -S-; n represents 1, 2 or 3.

Examples of the "C1-C8 linear alkyl group" include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl and the like.

Examples of the aforementioned "C1-C8 linear alkoxy group" include methoxy, ethoxy, n-propoxy, n-butoxy, n-pentyloxy, n-hexyloxy, n-heptyloxy base, n-octyloxy group, etc.

Examples of the aforementioned "C2-C8 linear alkenyl group" include vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 1-heptenyl, 2-heptenyl, 3-heptenyl, 1- Octenyl, 2-octenyl, 3-octenyl.

Examples of the aforementioned "C2-C8 linear alkenyloxy group" include ethyleneoxy, 1-propyleneoxy, 2-propyleneoxy, 1-butenyloxy, 2-butenyloxy, 3-butenyloxy, 1-pentenyloxy, 2-pentenyloxy, 1-hexenyloxy, 2-hexenyloxy, 3-hexenyloxy, 1-heptenyloxy, 2 -heptenyloxy, 3-heptenyloxy, 1-octenyloxy, 2-octenyloxy, 3-octenyloxy and the like.

The aforementioned "one or two non-adjacent -CH ₂ -optionally substituted by -O-" means that the aforementioned C1~C8 straight-chain alkyl, C1~C8 straight-chain alkoxy, C2~C8 Any -CH ₂ - in straight-chain alkenyl and C2~C8 straight-chain alkenyloxy is optionally substituted with -O-, but adjacent -CH ₂ - will not be substituted at the same time.

The aforementioned "any H is optionally substituted by an F atom" means that there is no limitation on the number of F substitutions, which may be monofluoro, polyfluoro, or perfluoro substituted.

Preferably, the aforementioned R ₁ and R ₂ each independently represent a hydrogen atom, a C1-C5 straight-chain alkyl group, a C1-C5 straight-chain alkoxy group, a C2-C5 straight-chain alkenyl group, or a C2-C5 Straight-chain alkenyloxy, wherein one or two non-adjacent -CH ₂ -s are optionally substituted by -O-, and any H is optionally substituted by F atoms.

The aforementioned "C1-C5 linear alkyl group" includes, for example, methyl, ethyl, n-propyl, n-butyl, and n-pentyl. Preferred is methyl, ethyl or n-propyl.

Examples of the "C1-C5 linear alkoxy group" include methoxy, ethoxy, n-propoxy, n-butoxy, and n-pentoxy. Preference is given to methoxy, ethoxy or n-propoxy.

Examples of the aforementioned "C2-C5 linear alkenyl group" include vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl. Preferred is vinyl, 1-propenyl, 3-butenyl, or 3-pentenyl.

Examples of the aforementioned "C2-C5 linear alkenyloxy group" include ethyleneoxy, 1-propyleneoxy, 2-propyleneoxy, 1-butenyloxy, 2-butenyloxy, 3-butenyloxy, 1-pentenyloxy, 2-pentenyloxy, 3-pentenyloxy. Preferably, it is ethyleneoxy, 1-propyleneoxy, 3-butenyloxy, or 3-pentenyloxy.

One or two of the aforementioned C1~C5 straight chain alkyl, C1~C5 straight chain alkoxy, C2~C5 straight chain alkenyl, or C2~C5 straight chain alkenyloxy are not adjacent The -CH ₂ - is optionally substituted by -O-, and any H is optionally substituted by an F atom.

In Formula I, n represents 1, 2, or 3. In view of obtaining a smaller response index value and thus a faster response time, n is preferably 1 or 2, and is more preferably n=1.

Among the liquid crystal compounds with negative dielectric anisotropy of the present invention, preferably, they are selected from the compounds represented by the following formulas IA~IR, Ia-Ir.

Wherein, the definitions of R ₁ and R ₂ are the same as above.

Further, the liquid crystal compound with negative dielectric anisotropy of the present invention is preferably selected from the group consisting of compounds represented by the following formulas IA-1~IR-4, Ia-1~Ir-4, wherein each of Alkyl Independently represent C1~C8 straight chain alkyl, Alkenyl each independently represent C2~C8 straight chain alkenyl,

[Preparation method of liquid crystal compound]

Next, the preparation method of the liquid crystal compound having negative dielectric anisotropy of the present invention will be described.

It should be understood that the preparation method of the liquid crystal compound with negative dielectric anisotropy of the present invention is not limited to the preparation method described below. Those skilled in the art can use other suitable methods for preparation.

In addition, part of the compounds described in formula I are described in the following descriptions, and other compounds can be obtained by those skilled in the art by referring to the following descriptions in combination with conventional technical means in the field.

The liquid crystal compound represented by the aforementioned formula IA is prepared by a method comprising the following preparation steps, wherein the definitions of R ₁ and R ₂ are the same as those described above.

Step A1: Dibenzofuran fluorination, dibenzofuran (A) reacts with butyllithium, and then reacts with NSFI (N-fluorobisbenzenesulfonamide) to obtain fluorinated dibenzofuran (B) ;

Step A2: reacting the aforementioned fluorinated dibenzofuran (B) with a lithium reagent, reacting with a boric acid ester, hydrolyzing to generate boric acid, and oxidizing to generate fluorinated dibenzofuran alcohol (C);

Step A3: The fluorinated dibenzofuran alcohol (C) obtained in the previous step A2 is reacted with the corresponding bromo(or chloro)cyclohexane (or benzene) substituted in the para position of _R1 under basic conditions to form a unilateral para Fluorinated dibenzofuran (D) substituted by cyclohexyl (or phenyl) methoxy at position R ₁ ;

Step A4: react the fluorinated dibenzofuran (D) substituted with _cyclohexyl (or phenyl) methoxyl group substituted by cyclohexyl (or phenyl) methoxy on one side para position again, react with butyllithium, then react with NSFI, and fluorinate again to obtain Difluorinated dibenzofuran (E) substituted by cyclohexyl (or phenyl) methoxyl substituted by unilateral para-position _R1 ;

Step A5: After reacting the difluorinated dibenzofuran (E) substituted by cyclohexyl (or phenyl) methoxyl substituted by unilateral para-position _R1 with lithium reagent, react with borate ester, hydrolyze to generate boronic acid, mono Side para-position R ₁ substituted cyclohexyl (or phenyl) methoxy difluorinated dibenzofuran alcohol (F);

Step A6: Difluorinated dibenzofuran alcohol (F) substituted with cyclohexyl (or phenyl) methoxy substituted by unilateral para-position R ₁ and the corresponding bromo (or chloro) ring substituted by para-position R ₂ Hexane (or benzene) reacts under alkaline conditions to produce two symmetrical or asymmetrical para-substituted cyclohexyl (or phenyl) methoxydifluorodibenzofuran (IA).

The liquid crystal compound represented by the aforementioned formula Ia is prepared by a method comprising the following preparation steps, wherein the definitions of R ₁ and R ₂ are the same as those described above.

Step a1: 2,3-difluorophenol (A) reacts with cyclohexylbromethane substituted by p-position _R1 in potassium carbonate acetonitrile solution under reflux and stirring. After the reaction, spin dry, and recrystallize with ethanol to obtain the compound (B) shown below;

Step a2: Dissolve compound (B) in THF, drop into butyllithium, then drop into tributyl borate, after obtaining the organic layer, prepare a compound containing 2-fluoro-6-bromophenol, sodium carbonate, tetratriphenyl The temperature of the solution of phosphine palladium, crown ether, etc. is raised under the protection of nitrogen, and then the above organic phase is dropped into the above-prepared solution, and the reaction is carried out with stirring. After the reaction, the organic layer was taken, spin-dried, and recrystallized with ethanol to obtain compound (C);

Step a3: Mix compound (C) and triethylamine, slowly add trifluoromethylsulfonyl chloride, and react while stirring. After the reaction, take the organic phase and spin dry to obtain compound (D);

Step a4: Dissolving compound (D) in sodium carbonate toluene solution, adding tetrakistriphenylphosphine palladium, ethyl mercaptopropionate and crown ether, and reacting while stirring to obtain an organic phase. Spin dry, recrystallize with ethanol to obtain compound (E);

Step a5: reacting compound (E) in potassium carbonate DMF while stirring to obtain an organic phase, spinning to dryness, and recrystallizing with ethanol to obtain compound (F);

Step a6: Dissolve compound (F) and potassium tert-butoxide in THF, add butyllithium dropwise, and stir. Add tributyl borate dropwise and react while stirring to obtain an organic layer. Add hydrogen peroxide to the obtained organic phase, react and stir to obtain the organic phase, spin dry, and recrystallize with ethanol to obtain compound (G);

Step a7: Mix compound (G) and para-position _R2 substituted cyclohexyl bromide in potassium carbonate acetonitrile solution, react while stirring, then spin dry, and recrystallize with toluene to obtain compound (Ia);

Above, the preparation method of the compound represented by the aforementioned formula IA and formula Ia is shown. For the preparation of other compounds, those skilled in the art can refer to the above-mentioned preparation methods, and according to the technical knowledge in the field, change the reaction raw materials in the above-mentioned preparation methods for preparation, without special limitation.

[Liquid Crystal Composition]

The liquid crystal composition of the present invention contains the aforementioned liquid crystal compound with negative dielectric anisotropy of the present invention.

In the liquid crystal composition of the present invention, one or more liquid crystal compounds with negative dielectric anisotropy of the present invention can be contained, and the content of each liquid crystal compound with negative dielectric anisotropy of the present invention can be calculated by weight percentage. For example, below 20%. From the viewpoint of low-temperature solubility, reliability, etc., it is preferably in the range of 15% or less. When multiple liquid crystal compounds with negative dielectric anisotropy of the present invention are contained, the total content of the liquid crystal compounds with negative dielectric anisotropy of the present invention may be, for example, 50% or less in weight percent.

In the liquid crystal composition of the present invention, in addition to the aforementioned liquid crystal compound with negative dielectric anisotropy, those skilled in the art can also add other liquid crystal compounds on the basis of not destroying the desired properties of the liquid crystal composition.

Optionally, various functional dopants may be added to the liquid crystal composition of the present invention, and these dopants include, for example, antioxidants, ultraviolet absorbers, and chiral agents.

As mentioned above, although the liquid crystal composition of the present invention contains the liquid crystal compound with negative dielectric anisotropy of the present invention, the composition of the present invention does not necessarily have negative dielectric anisotropy, and it can also be Positive dielectric anisotropy. A person skilled in the art can adjust the composition and proportion of each component of the composition as required to obtain a composition with desired anisotropy.

The preparation of the liquid crystal composition of the present invention is not particularly limited. containing this hair On the basis of the clear liquid crystal compound, those skilled in the art can select suitable other components for preparation as required.

[Liquid crystal display device]

The third aspect of the present invention provides a liquid crystal display device, which is not particularly limited as long as it contains the aforementioned liquid crystal compound with negative dielectric anisotropy of the present invention, or the aforementioned liquid crystal composition. The liquid crystal display device of the present invention may be an active matrix display device or a passive matrix display device. Those skilled in the art can select a suitable liquid crystal display element and structure of the liquid crystal display according to the required performance.

Example 1

(COBOIC-3-3)

synthetic route:

34g of dibenzofuran was dissolved in 200ml of THF and cooled to -50°C, 88ml of butyllithium was added dropwise at -40°C, and stirred for 1h. Cool to -50°C, dissolve 65g NSFI in 300ml THF and drop in, Naturally rise to room temperature and stir for 6hrs. Add 300ml of water and 200ml of toluene, stir for 0.5hr, and separate layers to obtain an organic layer. Wash the organic phase 3 times with deionized water, dry, and spin dry to obtain 37.2g DL-01-01; 37.2g DL-01-01 was dissolved in 300ml THF, cooled to -78°C, and 88ml butyllithium was dissolved in - Add dropwise at 70°C and stir for 1 hr. Cool to -78°C, add 50g of tributyl borate dropwise, let it rise to room temperature naturally, and stir for 6hrs. Add 200 ml of water containing 50 ml of concentrated hydrochloric acid, stir for 0.5 hr, and separate layers to obtain an organic layer. Add 30ml of 30% hydrogen peroxide to the obtained organic phase, and stir at room temperature for 2h. THF was distilled away under atmospheric pressure, extracted twice with DCM, the organic phases were combined, spin-dried, and recrystallized with ethanol to obtain 32g DL-01-02; 32g DL-01-02, 38.5g p-propylcyclohexyl bromide, g of potassium carbonate was stirred at reflux in 200ml of acetonitrile for 8hrs. Spin dry, add 200ml toluene, wash 4 times with deionized water, dry, and spin dry to get 51g DL-01-03; Add dropwise at -40°C and stir for 1 hr. Cool to -50°C, dissolve 52g NSFI in 300ml THF and add dropwise, naturally warm to room temperature, and stir for 6hrs. Add 200ml of water and 180ml of toluene, stir for 0.5hr, and separate layers to obtain an organic layer. The organic phase was washed 3 times with deionized water, dried, and spin-dried to obtain 50g DL-01-04; 50g DL-01-04 was dissolved in 180ml THF, cooled to -78°C, and 58ml butyllithium was placed at -70°C Add dropwise and stir for 1hr. After cooling to -78°C, 35.4 g of tributyl borate was added dropwise, and the mixture was naturally raised to room temperature, and stirred for 6 hrs. Add 200 ml of water containing 43 ml of concentrated hydrochloric acid, stir for 0.5 hr, and separate layers to obtain an organic layer. Add 18ml of 30% hydrogen peroxide to the obtained organic phase, and stir at room temperature for 2hrs. Distill THF away under normal pressure, extract twice with DCM, combine the organic phases, spin dry, and recrystallize with ethanol to obtain 41.1g DL-01-05; 41.1g DL-01-05, 26.3g p-propylcyclohexylbromethane , 16.2g potassium carbonate was refluxed and stirred in 200ml acetonitrile for 8hrs. Spin dry, add 200ml toluene, wash 4 times with deionized water, dry, Spin dry, and recrystallize twice with ethanol to obtain 28g DL-01. Purity: 99.9%.

The mass spectrum and 1H NMR data of the prepared compound DL-01 (COBOIC-3-3) are as follows: MS (EI, m/z): 236,374,512.

1H-NMR (500MHZ, CDCl3, ppm): 7.44-7.46 (2H, d), 6.94-6.98 (2H, t), 3.90-3.92 (4H, d), 1.93-1.96 (4H, d), 1.80-1.83 (6H, d), 1.30-1.34 (4H, m), 1.17-1.21 (6H, m), 1.07-1.11 (4H, m), 0.90-0.97 (4H, m), 0.87-0.91 (6H, t)

Example 2

(COBOIC-3-V)

In addition to changing the 26.3g p-propylcyclohexyl bromide used in the step of preparing DL-01 from DL-01-05 in Example 1 to 24.4g p-vinylcyclohexyl bromide, the rest are the same as in Example 1, preparing Compound COBOIC-3-V represented by the following structural formula.

The prepared compound COBOIC-3-V was tested by mass spectrometry and 1H NMR. The data obtained from the test are as follows: MS (EI, m/z): 236,358,496.

1H-NMR (500MHZ, CDCl3, ppm): 7.44-7.46 (2H, d), 6.94-6.98 (2H, t), 5.74-5.84 (1H, m), 5.00-5.02 (2H, dd), 3.90-3.94 (4H, dd), 1.96-2.00 (5H, m), 1.80-93 (6H, m), 1.30-1.34 (2H, m), 1.17-1.23 (7H, m), 0.94-1.07 (4H, m) , 0.90-0.96 (3H, m)

Example 3

(COBOIC-V-V)

In addition to changing the 38.5g p-propylcyclohexyl bromide used in the step of preparing DL-01-03 from DL-01-02 in Example 1 to 35.7g p-vinylcyclohexyl bromide, and will be prepared from DL-01-05 The 26.3g p-propylcyclohexyl bromide used in the step of DL-01 was changed to 24.4g p-vinylcyclohexyl bromide, and the rest were the same as in Example 1 to prepare the compound COBOIC-V-V shown in the following structural formula.

The prepared compound was tested by mass spectrometry and 1H nuclear magnetic resonance spectrum, and the data obtained by the test are as follows. According to the test results, the compound has the structure shown in COBOIC-3-V.

MS (EI.m/z): 236,358,480.

1H-NMR (500MHZ, CDCl3, ppm): 7.44-7.47 (2H, d), 6.94-6.98 (2H, t), 5.74-5.84 (2H, m), 5.00-5.02 (4H, dd), 3.90-3.94 (4H, dd), 1.96-2.00 (6H, m), 1.80-93 (6H, m), 1.17-1.23 (8H, m)

Example 4

COB(S)OIC-3-3

synthetic route:

26g of 2,3-difluorophenol, 48.4g of p-propylcyclohexyl bromide, and 31g of potassium carbonate were stirred at reflux in 300ml of acetonitrile for 8hrs. Spin dry, add 300ml toluene, wash with deionized water 4 times, dry, spin dry, recrystallize with ethanol to get 48.2g DL-02-01.

48.2g of DL-02-01 was dissolved in 240ml of THF, cooled to -78°C, 80ml of butyllithium was added dropwise at -70°C, heated to -60°C, and stirred for 1 hr. After cooling to -78°C, 46 g of tributyl borate was added dropwise, and the mixture was naturally raised to room temperature, and stirred for 6 hrs. Add 100 ml of an aqueous solution containing 23 ml of concentrated hydrochloric acid, stir for 0.5 hr, and separate layers to obtain an organic layer. 34.2g 2-fluoro-6-bromophenol, 48g sodium carbonate, 300ml toluene, 100ml water, 0.3g tetrakistriphenylphosphine palladium, 1.0g crown ether, heated to 60°C under nitrogen protection, the organic phase obtained above was dropped into , stirred at 70 °C for 5 hrs. After cooling, the reaction solution was neutralized to acidity with hydrochloric acid, separated into layers, and the organic phase was washed twice with deionized water. Dry, spin dry, and recrystallize with ethanol to obtain 60.5g DL-02-02.

60.5g DL-02-02, 20g triethylamine and 300ml DCM were mixed and cooled to 0°C, 28.5g trifluoromethylsulfonyl chloride was added slowly, the internal temperature was controlled at 5°C, and stirred for 8h. The organic phase was washed with deionized water until neutral, dried, and spin-dried to obtain 81 g of DL-02-03.

81g DL-02-03, 48g sodium carbonate, 300ml toluene, 100ml water, 0.3g four three Phenylphosphine palladium, 24g ethyl mercaptopropionate, 1.0g crown ether, heated to reflux for 12hrs under nitrogen protection. After cooling, the organic phase was washed 3 times with deionized water. Dry, spin dry, and recrystallize with ethanol to obtain 69g of DL-02-04.

69g of DL-02-04 and 23g of potassium carbonate were stirred in 200ml of DMF at 120°C for 8hrs. Add 200ml of toluene and 100ml of deionized water, and separate layers; the organic phase is washed 3 times with deionized water, dried, spin-dried, and recrystallized with ethanol to obtain 45g of DL-02-05.

45g of DL-02-05 and 15g of potassium tert-butoxide were dissolved in 300ml of THF, cooled to -78°C, 54ml of butyllithium was added dropwise at -70°C, and stirred for 1 hr. After cooling to -78°C, 30 g of tributyl borate was added dropwise, and the mixture was naturally raised to room temperature, and stirred for 6 hrs. Add 200 ml of water containing 18 ml of concentrated hydrochloric acid, stir for 0.5 hr, and separate layers to obtain an organic layer. Add 15ml of 30% hydrogen peroxide to the obtained organic phase, and stir at room temperature for 2hrs. THF was distilled away under normal pressure, extracted twice with DCM, the organic phases were combined, spin-dried, and recrystallized with ethanol to obtain 39g DL-02-06; 39g DL-02-06, 24.2g p-propylcyclohexyl bromide, 15g Potassium carbonate was stirred at reflux in 200ml of acetonitrile for 8hrs. Spin dry, add 200ml toluene, wash 4 times with deionized water, dry, spin dry; recrystallize with toluene to get 42g DL-02, purity: 99.9%.

The prepared compound was tested by mass spectrometry and 1H nuclear magnetic resonance spectrum, and the data obtained by the test are as follows. According to the test results, the compound has the structure shown as COB(S)OIC-3-3.

MS (EI, m/z): 252,390,528.

1H-NMR (500MHZ, CDCl3, ppm): 7.38-7.40 (2H, d), 6.90-6.94 (2H, t), 3.90-3.92 (4H, d), 1.93-1.96 (4H, d), 1.80-1.83 (6H, d), 1.30-1.34 (4H, m), 1.17-1.21 (6H, m), 1.07-1.11 (4H, m), 0.90-0.97 (4H, m), 0.87-0.91 (6H, t)

Example 5

In addition to changing the 24.2g p-propylcyclohexyl bromide used in the step of preparing DL-02 from DL-02-06 in Example 4 to 22.4g p-vinylcyclohexyl bromide, the rest are the same as in Example 4, preparing Compound COB(S)OIC-3-V represented by the following structural formula.

COB(S)OIC-3-V

The prepared compound was tested by mass spectrometry and 1H nuclear magnetic resonance spectrum, and the data obtained by the test are as follows. According to the test results, the compound has the structure shown as COB(S)OIC-3-V.

MS (EI, m/z): 252,374,512.

1H-NMR (500MHZ, CDCl3, ppm): 7.38-7.41 (2H, d), 6.89-6.93 (2H, t), 5.74-5.84 (1H, m), 5.00-5.02 (2H, dd), 3.90-3.94 (4H, dd), 1.96-2.00 (5H, m), 1.80-93 (6H, m), 1.30-1.34 (2H, m), 1.17-1.23 (7H, m), 0.94-1.07 (4H, m) , 0.90-0.96 (3H, m)

Example 6

In addition to changing the 48.4g p-propylcyclohexyl bromide used in the step of preparing DL-02-01 from difluorophenol in Example 4 to 44.9g p-vinylcyclohexyl bromide, and preparing DL- The 24.2g p-propyl cyclohexyl bromide used in the step of 02 is changed to 22.4g p-vinyl cyclohexyl bromide except that all the other are the same as in Example 4 to prepare the compound COB(S)OIC-V-V shown in the following structural formula .

The prepared compound was tested by mass spectrometry and 1H nuclear magnetic resonance spectrum, and the data obtained by the test are as follows. According to the test results, the compound has the structure shown as COB(S)OIC-V-V.

COB(S)OIC-V-V

MS (EI, m/z): 252,374,496.

1H-NMR (500MHZ, CDCl3, ppm): 7.38-7.41 (2H, d), 6.89-6.93 (2H, t), 5.74-5.84 (2H, m), 5.00-5.02 (4H, dd), 3.90-3.94 (4H, dd), 1.96-2.00 (6H, m), 1.80-93 (6H, m), 1.17-1.23 (8H, m)

Example 7

(PVOBOIC-3-3)

Except that the 26.3g p-propylcyclohexylbromethane used in the step of preparing DL-01 by DL-01-05 in Example 1 was changed to 27.0g p-propylphenyl bromide, the rest were the same as in Example 1, and the following Compound PVOBOIC-3-3 shown in the above structural formula.

Example 8

(CQBQIC-3-3)

In addition to changing the 38.5g p-propylcyclohexyl bromide used in the step of preparing DL-01-03 from DL-01-02 in Example 1 to 44.8g p-propylcyclohexyl difluorobromethane, and the DL-01- 05 Except that 26.3g of p-propylcyclohexyl bromide used in the step of preparing DL-01 was changed to 30.6g of p-propylcyclohexyl difluorobromethane, the rest was the same as in Example 1, and the compound CQBQIC shown in the following structural formula was prepared -3-3.

Example 9

(PQBQIC-3-3)

In addition to changing the 38.5g p-propylcyclohexyl bromide used in the step of preparing DL-01-03 from DL-01-02 in Example 1 to 44.8g p-propylcyclohexyl difluorobromethane, and the DL-01- 05 Except that 26.3g of p-propylcyclohexyl bromide used in the step of preparing DL-01 was changed to 29.9g of p-propylphenyldifluorobromomethane, the rest was the same as in Example 1, and the compound PQBQIC shown in the following structural formula was prepared -3-3.

Example 10

(PVQBQIC-3-3)

In addition to changing the 38.5g p-propylcyclohexyl bromide used in the step of preparing DL-01-03 from DL-01-02 in Example 1 to 44.8g p-propylcyclohexyl difluorobromethane, and the DL-01- 05 Except that 26.3g of p-propylcyclohexylbromethane used in the step of preparing DL-01 was changed to 33.0g of p-propylphenyl difluoropropene bromide, the rest was the same as in Example 1, and the compound shown in the following structural formula was prepared PVQBQIC-3-3.

For each compound of the preceding examples and comparative examples shown in the following Table 1, T _NI , Δn, Δε, K ₁₁ , K ₃₃ , G1, etc. were measured under the following conditions, and the physical property test results are shown in the following table In 2, the response index values G1/(K ₁₁ *△n*△n*T _NI ) and G1/(K ₃₃ *△n*△n*T _NI ) calculated based on these test results are shown in Table 3 below In VA (vertical alignment, vertical alignment) or PS-VA (Polymer stabilized vertical alignment, polymer stabilized vertical alignment) mode, the response time of the liquid crystal medium and the index G1/(K ₃₃ *△n*△n*T _NI ) correlation, while in FFS (Fringe Field Switching, fringe field switching), IPS (In-Plane Switching, plane switching), PS-FFS (Polymer stabilized Fringe Field Switching, polymer stabilized fringe field switching), PS-IPS ( In the Polymer stabilized In-Plane Switching mode, the response time of the liquid crystal medium is related to the response index value G1/(K ₁₁ *△n*△n*T _NI ). The smaller the aforementioned response index value, the faster the response time.

T _NI represents the temperature at which the liquid crystal monomer changes from a nematic phase to a clear phase, and its temperature is measured by MP-90 equipment; Δn represents the refractive index, Δn=n _e -n _o , where n _o is the refractive index of ordinary light , ne _is the refractive index of extraordinary light, test conditions: 589nm, 25±0.2℃.

Δε represents dielectric anisotropy, Δε=ε _∥ -ε _⊥ , where ε _∥ is the dielectric constant parallel to the molecular axis, ε _⊥ is the dielectric constant perpendicular to the molecular axis, test conditions: 25°C, INSTEC: ALCT-IR1, 18 micron vertical box; K ₁₁ is the torsional elastic constant, K ₃₃ is the splay elastic constant, the test conditions are: 25°C, INSTEC: ALCT-IR1, 18 micron vertical box; Gamma1 (mPa.s) is the rotation Viscosity coefficient, abbreviated as "G1", the test conditions are: 25°C, INSTEC: ALCT-IR1, 18 micron vertical cell.

From the comparison of the response indicators of Examples 1-10 and Comparative Examples in Table 3, it can be seen that the response indicators of the liquid crystal compounds in Examples 1-10 are G1/(K ₁₁ *Δn*Δn*T _NI ), G1/(K ₃₃ *△n*△n*T _NI ) decreased compared to the comparative example, especially G1/(K ₁₁ *△n*△n*T _NI ) decreased significantly.

As can be seen from Table 2, although the G1 values of liquid crystal compounds 1 to 10 of the examples are higher than those of the comparative example, the clearing point T _NI (° C.) is significantly improved compared to the comparative example 1, and the elastic coefficient K11 (pN ), K33(pN) were significantly improved relative to Comparative Example 1, thereby contributing to the reduction of the response index value.

The present invention may be embodied in other specific forms without departing from the spirit or main characteristics of the invention. Therefore, no matter from which point of view, the above-mentioned embodiments of the present invention can only be regarded as descriptions of the present invention and cannot limit the present invention, and the claims have pointed out the scope of the present invention, and the above description does not point out the scope of the present invention. Therefore, any changes within the meaning and scope equivalent to the claims of the present invention should be considered to be included in the scope of the claims of the present invention.

Claims (4)

A liquid crystal compound with negative dielectric anisotropy, which is selected from the group consisting of compounds represented by the following formulas IA~IR, Ib~Ir, wherein R ₁ and R ₂ each independently represent a hydrogen atom, C1~C8 straight chain alkyl, C1~C8 straight chain alkoxy, C2~C8 straight chain alkenyl, or C2~C8 straight chain alkenyloxy, one or two of which are not adjacent -CH ₂ - is optionally substituted by -O-, wherein any H is optionally substituted by an F atom;

A liquid crystal compound with negative dielectric anisotropy is selected from the group consisting of compounds shown in the following formulas IA-1~IR-4, Ia-1, Ia-3, Ib-1~Ir-4, Wherein, Alkyl each independently represents a straight-chain alkyl group of C1~C8, and Alkenyl each independently represents a straight-chain alkenyl group of C2~C8,

A liquid crystal composition comprising the liquid crystal compound with negative dielectric anisotropy described in claim 1 or 2. A liquid crystal display device, comprising the liquid crystal compound with negative dielectric anisotropy described in claim 1 or 2, or comprising the liquid crystal composition described in claim 3, the liquid crystal display device is an active matrix display device , or passive matrix display devices.

Images