TWI608086B - A liquid crystal compound having bicyclo[3.3.0] octyl-7-ene-based structure, a liquid crystal composition comprising said compound and applicaton thereof - Google Patents

Description

Liquid crystal compound containing bicyclo[3.3.0]oct-7-ene structure, liquid crystal composition thereof and application thereof

The present invention relates to a liquid crystal compound and a composition and application comprising the same, and more particularly to a novel liquid crystal compound containing a bicyclo[3.3.0]oct-7-ene structure and a liquid crystal composition comprising the liquid crystal compound And application.

Physically, the matter is divided into three states, namely solid, liquid and gaseous. In nature, most materials exhibit only three states of solid state, liquid state and gas state with temperature. Liquid crystal is a new material state different from the usual solid, liquid and gaseous states. It can be in a certain temperature range. The state of matter in which both the liquid and the crystal are characteristic, also referred to as the liquid crystal phase or the intermediate phase, is also referred to as the fourth state of matter.

There are many types of liquid crystals, and there are thousands of naturally occurring and synthetic liquid crystals, but they are basically organic compounds. According to the conditions formed by the liquid crystal phase, the liquid crystal can be classified into a thermotropic liquid crystal, a lyotropic liquid crystal, an inductive liquid crystal, and a flow-through liquid crystal.

Currently, liquid crystal materials for display are basically thermotropic liquid crystals. Thermotropic liquid crystals can be classified into smectic crystals due to different molecular arrangement states. Liquid crystal (Smectic, also known as lamellar liquid crystal), nematic liquid crystal (Nematic, also known as filamentous liquid crystal), cholesterol liquid crystal (Cholesteric, also known as spiral liquid crystal). The physical properties of these phases are known. Molecular structural features of compounds used in the field of optoelectronics, usually having a rigid backbone comprising, for example, linked 1,4-phenylene or 1,4-cyclohexylene or heterocyclic systems, as far as possible from each other The position is substituted by a terminal group such as an alkyl group, an alkoxy group or a cyano group.

The liquid crystal composition used in the field of optoelectronics is composed of a mixture of these compounds, and a compound which does not have a mutual transformation from a crystal phase to a liquid crystal is also used therein. According to the liquid crystal display method, the liquid crystal mixture can be classified into a dynamic scattering type (DS type), a host type (GH type), a twisted nematic type (TN type), a super twisted nematic type (STN type), a thin film transistor type ( TFT type) and ferroelectric type (FLC type). Liquid crystal materials have been widely used in the production of liquid crystal display elements such as tablet computers, various measuring instruments, automobile instrument panels, notebook computers, mobile phone handsets, computers, and televisions.

To date, liquid crystal materials have been synthesized into a variety of compounds, depending on the mode of display or the manner of driving and their use. However, on the other hand, the demand for improving the performance of liquid crystal display elements has been increasing year by year, and in order to meet this demand, it is necessary to continue to develop novel liquid crystal compounds.

Accordingly, it is an object of the present invention to provide a novel liquid crystal compound containing a bicyclo[3.3.0]oct-7-ene structure.

Accordingly, the present invention provides a novel liquid crystal compound containing a bicyclo[3.3.0]oct-7-ene structure having a structure represented by the general formula (I): Wherein R ₁ represents a linear or branched alkyl or alkoxy group of _{1 to} 20 carbon atoms which is substituted or unsubstituted with at least one halogen, wherein at least one -CH ₂ - in the R ₁ may be - O-, -S-, -SiH ₂ -, -CH=CH-, -C≡C-, -CF=CF-, -CH=CF-, -COO- or -OCO-substitution, provided that the hetero atom Not directly connected to each other, and the O, S and Si atoms are not directly connected to the ring; R ₂ represents -H, -F, -Cl, -CN, -NCS, -SCN, -OCN, -NCO, Or a straight or branched alkyl or alkoxy group having 1 to 20 carbon atoms substituted or unsubstituted with at least one halogen, wherein at least one -CH ₂ - in the R ₂ may be -O-, - S-, -SiH ₂ -, -CH=CH-, -C≡C-, -CF=CF-, -CH=CF-, , -COO- or -OCO-substitution, provided that the heteroatoms are not directly connected to each other; ring A ₁ represents Rings A ₂ , A ₃ , and A _{4 are the} same or different and each independently represents The cyclic structure represented by the rings A ₁ , A ₂ , A ₃ , and A ₄ may also conform to at least one of the following a), b), c), and d): a) the ring One or more hydrogen atoms in the structure may be -D, -F, -Cl, -CN, -CF ₃ , -OCF ₃ , -CH ₂ F, -OCH ₂ F, -CF ₂ H, -OCF ₂ H , -OCH ₃ or -CH ₃ substituted; b) one or more -CH ₂ - in the cyclic structure is substituted by -O-, -SiH ₂ -, -S- or -CO-, provided that the heteroatoms are Not directly connected; c) in the cyclic structure, one or more -CH- in the aromatic ring structure may be substituted by N; d) one or more of the cyclic structures Can be Substituted; Z ₁ represents -CF ₂ O-, -CH ₂ O-, -CH ₂ CH ₂ -, -CH ₂ CF ₂ -, -CF ₂ CH ₂ -, -(CH ₂ ) ₄ -, -CH ₂ CH ₂ CF ₂ O-, -CH ₂ CF ₂ OCH ₂ -, -CH ₂ CH ₂ CH=CH-, -C ₂ H ₄ OCH ₂ -, -CH ₂ CH=CHCH ₂ -, -CH ₂ CH ₂ CH ₂ O-, -C≡C- or a single bond; Z ₂ , Z ₃ and Z _{4 are the} same or different and each independently represents a single bond, -COO-, -CF ₂ O-, -CH ₂ O-, -CH ₂ CH ₂ -, -CF ₂ CH ₂ -, -CF=CF-, -CH=CH-, -CH=CF-, -C ₂ F ₄ -, -(CH ₂ ) ₄ -, -C ₄ F ₈ - _{, -OCF 2 CF 2 O -,} - CF 2 CF 2 CF 2 O -, - CH 2 CH 2 CF 2 O-, -OCF 2 CF 2 CF 2 -, - CH 2 CF 2 OCH 2 -, - CH = CHCF ₂ O-, -CF ₂ OCH=CH-, -CF ₂ OCF=CH-, -CF ₂ OCH=CF-, -CF=CFCF ₂ O-, -CH=CFCF ₂ O-, -CF ₂ OCF= CF-, -CH=CHCH ₂ CH ₂ -, -C ₂ H ₄ OCH ₂ -, -CH ₂ CH=CHCH ₂ -, -OCH ₂ CH ₂ CH ₂ -, -CF=CF-CF=CF-, - C≡C-CF=CF-, -C≡C-CF=CF-C≡C-, -CF=CF-C≡C-CF=CF-, -C≡C-CF ₂ O- or -C≡ C-, wherein the Z _2, Z _3, and linking group Z ₄ is any one of -CH ₂ - may be -SiH ₂ - substituted; are the same or different m, n and p, each independently represent 0,1 Or 2. When m is 2, two Z ₂ and two A ₂ are the same or different; when n is 2, two Z ₃ and two A ₃ are the same or different; when p is 2, two Z ₄ and The two A ₄ are each the same or different.

Another object of the present invention is to provide a method for synthesizing the liquid crystal compound.

It is still another object of the present invention to provide a composition comprising the liquid crystal compound.

A further object of the present invention is to provide a liquid crystal composition for use in a liquid crystal cell, which can be applied to a liquid crystal cell containing a liquid crystal medium such as TN, STN, TFT, VA, ECB, OCB, LCP, PDLC, BiNem, LC. Display mode liquid crystal elements such as LENS, FFS, and IPS.

The liquid crystal compound containing a bicyclo[3.3.0]oct-7-ene structure of the formula (I) of the present invention has a novel structure and has a low viscosity, a large optical anisotropy and a large dielectric anisotropy. . The liquid crystal composition of the present invention has the effect of using a liquid crystal compound of the formula (I), and can be applied to various display modes. Liquid crystal element.

Hereinafter, the present invention will be described in detail: preferably, R ₁ represents a linear or branched alkyl or alkoxy group having _{1 to} 10 carbon atoms substituted or unsubstituted with at least one halogen, wherein At least one of -CH ₂ - in R ₁ may be -O-, -S-, -SiH ₂ -, -CH=CH-, -C≡C-, -CF=CF-, -CH=CF-, -COO - or -OCO-substitution, provided that the heteroatoms are not directly connected to each other, and the O, S and Si atoms are not directly bonded to the ring; R ₂ represents -H, -F, -Cl, -CN, -NCS, And a linear or branched alkyl or alkoxy group having 1-10 carbon atoms substituted or unsubstituted with at least one halogen, wherein at least one -CH ₂ - in the R ₂ may be -O-, - CH=CH-, -C≡C-, -CF=CF-, -CH=CF-, Or -COO-substitution, provided that the heteroatoms are not directly connected to each other.

Preferably, ring A ₁ represents Rings A ₂ , A ₃ and A _{4 are the} same or different and each independently represents

More preferably, the ring A ₁ represents Rings A ₂ , A ₃ and A _{4 are the} same or different and each independently represents

Preferably, Z ₁ represents -CH ₂ O-, -CH ₂ CH ₂ -, -CH ₂ CF ₂ -, -CF ₂ CH ₂ -, -(CH ₂ ) ₄ -, -CH ₂ CH ₂ CF ₂ O -, -CH ₂ CF ₂ OCH ₂ -, -CH ₂ CH ₂ CH=CH-, -C ₂ H ₄ OCH ₂ -, -CH ₂ CH ₂ CH ₂ O-, -C≡C- or a single bond; Z ₂ , Z ₃ , and Z _{4 are the} same or different and each independently represents -COO-, -CF ₂ O-, -CH ₂ O-, -CH ₂ CH ₂ -, -CF=CF-, -CH=CH- , -C ₂ F ₄ -, -(CH ₂ ) ₄ -, -C ₄ F ₈ -, -OCF ₂ CF ₂ O-, -CH ₂ CH ₂ CF ₂ O-, -CF=CFCF ₂ O-, - C ₂ H ₄ OCH ₂ -, -OCH ₂ CH ₂ CH ₂ -, -C≡C- or a single bond.

More preferably, Z ₁ represents -CH ₂ O-, -CH ₂ CH ₂ -, -CH ₂ CF ₂ -, -CF ₂ CH ₂ -, -(CH ₂ ) ₄ -, -CH ₂ CH ₂ CF ₂ O -, -CH ₂ CF ₂ OCH ₂ -, -CH ₂ CH ₂ CH=CH-, -C ₂ H ₄ OCH ₂ -, -CH ₂ CH ₂ CH ₂ O-, -C≡C- or a single bond; Z ₂ , Z ₃ , and Z _{4 are the} same or different and each independently represents -COO-, -CF ₂ O-, -CH ₂ O-, -CH ₂ CH ₂ -, -CF=CF-, -CH=CH- , -C ₂ F ₄ -, -(CH ₂ ) ₄ -, -C ₄ F ₈ -, -OCF ₂ CF ₂ O-, -CF=CFCF ₂ O-, -C≡C- or a single bond.

Preferably, m, n and p are the same or different, each independently representing 0, 1 or 2, and m+n+p 4.

Preferably, the compound of formula (I) is represented Wherein R ₁ represents a straight or branched alkyl or alkoxy group of _{1 to} 5 carbon atoms which is substituted or unsubstituted with at least one halogen, wherein at least one -CH ₂ - in the R ₁ may be - O-, -S-, -SiH ₂ -, -CH=CH-, -C≡C-, -CF=CF-, -CH=CF-, -COO- or -OCO-substitution, provided that the hetero atom Not directly connected to each other, and the O, S and Si atoms are not directly bonded to the ring; R ₂ represents -H, -F, -CN and a straight or branched chain of 1-5 carbon atoms substituted or unsubstituted by at least one halogen An alkyl or alkoxy group of a chain wherein at least one -CH ₂ - in the R ₂ may be -O-, -CH=CH-, -C≡C-, -CF=CF-, -CH=CF -, Or -COO-substitution, provided that the heteroatoms are not directly linked to each other; Z ₁ represents -CH ₂ O-, -CH ₂ CH ₂ -, -CH ₂ CF ₂ -, -CF ₂ CH ₂ -, -(CH _{2 4} -, -CH ₂ CH ₂ CF ₂ O-, -CH ₂ CF ₂ OCH ₂ -, -CH ₂ CH ₂ CH ₂ O-, -C≡C- or a single bond; Z ₂ , Z ₃ , and Z ₄ identical or different, each independently represents -COO-, -CF ₂ O-, -CH ₂ O-, -CH ₂ CH ₂ -, -CF=CF-, -CH=CH-, -C ₂ F ₄ - , -OCF ₂ CF ₂ O-, -CF=CFCF ₂ O-, -C≡C- or a single bond; L ₁ ~ L ₄ independently of each other represent -H, -F or -CH ₃ ; L ₅ ~ L ₁₆ Each independently represents -H, -F, -OCF ₂ H, -CH ₃ , -OCH ₃ , -OCF ₃ or -CF ₃ .

Another object of the present invention is to provide a method of preparing the above liquid crystal compound, comprising the steps of:

The compound of the formula (III-3) is mainly synthesized by a commercially available intermediate or a published synthesis method, and the published synthesis methods include an esterification reaction, a Wittig reaction, and a carbon-carbon cross-coupling reaction (Suzuki coupling). , Negishi coupling, Heck coupling, Sonogashira coupling and transition metal catalysis and Grignard reagent cross-coupling reaction, etc.), Grignard reaction, catalytic hydrogenation and bromination reaction, etc.; or synthesized by the following route.

Wherein X ₁ is H, F, Cl, Br, I or a sulfonate group or the like. The compound of the formula (III) is mainly synthesized by a commercially available intermediate or a published synthesis method, wherein the published synthesis methods include an esterification reaction, a Wittig reaction, a carbon-carbon cross-coupling reaction (Suzuki coupling, Negishi). Coupling, Heck coupling, Sonogashira coupling and transition metal catalysis and Grignard reagent cross-coupling reaction, etc.), Grignard reaction, catalytic hydrogenation and substitution reaction.

R ₅ MgX ₂ (IV)R ₅ is a linear or branched alkyl or alkoxy group having ₁ to 9 carbon atoms which is substituted or unsubstituted with at least one halogen, wherein at least one -CH in the R _{5 2} - may be substituted by -O-, -S-, -SiH ₂ -, -CH=CH-, -C≡C-, -CF=CF-, -CH=CF-, -COO- or -OCO-, The premise is that the heteroatoms are not directly connected to each other, and the O, S and Si atoms are not directly connected to the ring; X ₂ is F, Cl, Br or I; the compound of the formula (IV) is mainly a commercially available intermediate or Prepared by the classical method of preparing format reagents.

R ₆ is a linear or branched alkyl or alkoxy group of 1-8 carbon atoms which is substituted or unsubstituted with at least one halogen, wherein at least one -CH ₂ - in the R ₆ may be -O- , -S-, -SiH ₂ -, -CH=CH-, -C≡C-, -CF=CF-, -CH=CF-, -COO- or -OCO-substitution, provided that the heteroatoms are not Directly linked, and the O, S and Si atoms are not directly attached to the ring; X ₃ is Cl, Br or I; the compound of formula (V) is mainly a commercially available intermediate or a published precursor for the preparation of Wittig reagent -- A classical method of triphenylphosphine salt is prepared.

R ₇ -OH (VI)R ₇ is a straight or branched alkyl or alkoxy group of 1-8 carbon atoms which is substituted or unsubstituted with at least one halogen, wherein at least one -CH in the R _{7 2} - may be substituted by -O-, -S-, -SiH ₂ -, -CH=CH-, -C≡C-, -CF=CF-, -CH=CF-, -COO- or -OCO-, The premise is that the heteroatoms are not directly connected to each other, and the O, S and Si atoms are not directly connected to the ring; the main reaction process is as follows:

1) After reacting diethyl malonate with sodium ethoxide, a substitution reaction with a compound of the formula (III) is carried out to obtain a compound of the formula (III-1); or diethyl malonate in a solvent of tetrahydrofuran, nitrogen protection Under, at 65 to 70 ° C The compound of the formula (III) can be subjected to the Suzuki-Miyaura reaction to give a compound of the formula (III-1).

2) The compound of the formula (III-1) is added to the tetrahydrogen aluminum lithium in the range of 0 to 10 ° C under anhydrous nitrogen in anhydrous tetrahydrofuran, and the mixture is raised to room temperature (25 ± 3 ° C) for 2 hours to reduce. The compound of the formula (III-2) is obtained.

3) The compound of the formula (III-2) is added to 2.2 equivalents of a bromine reagent in a range of 0 to 5 ° C under a nitrogen atmosphere in dichloromethane, and heated to 20 to 44 ° C for 4 to 24 hours, that is, A compound of the formula (III-3) can be obtained; wherein the bromination reagent includes phosphorus tribromide, triphenylphosphine + bromine + imidazole or triphenylphosphine + carbon tetrabromide and the like.

4) The lithium diisopropylamide solution is added dropwise to the dimethyl succinate and hexamethylphosphinamide in an anhydrous tetrahydrofuran solvent under an argon atmosphere at a temperature of -80 to -75 °C. In a tetrahydrofuran solution, a tetrahydrofuran solution of the compound of the formula (III-3) is added dropwise at -80 to -75 ° C, and the mixture is heated to room temperature (25 ± 3 ° C) for 20 hours to obtain a formula (III- 4) Compound.

5) Under an argon atmosphere, in the range of -80 to -75 ° C, cyclohexylisopropylamine is added dropwise to a solution of 1.1 equivalents of n-butyllithium in tetrahydrofuran, and 0.5 equivalent of the formula (III) is added dropwise. -4) A solution of the compound in tetrahydrofuran, followed by dropwise addition of 0.5 equivalent of a solution of iodine in tetrahydrofuran at -80 to -75 ° C, heating to room temperature (25 ± 3 ° C), and then quenching the reaction with dilute hydrochloric acid to give the formula (III-5) compound.

6) The compound of the formula (III-5) is added in an anhydrous tetrahydrofuran under a nitrogen atmosphere at a range of 0 to -5 ° C in portions, and then reacted at 0 to -5 ° C for 1 hour to obtain a pass. a compound of formula (III-6).

7) a compound of the formula (III-6), 2.2 equivalents of triphenylphosphine and 2.2 equivalents of imidazole in dichloromethane, under a nitrogen atmosphere, adding 2.2 equivalents of bromine in the range of 0 to 5 ° C, heated to 20 The compound of the formula (III-7) can be obtained by reacting at 44 ° C for 4 to 24 hours.

8) A solution of diethyl malonate in tetrahydrofuran is added dropwise to diisopropyl in an anhydrous tetrahydrofuran solvent under an argon atmosphere at a temperature of -80 to -75 °C. The solution of the lithium amide in tetrahydrofuran is then added dropwise to the tetrahydrofuran solution of the compound of the formula (III-7) at -80 to -75 ° C, and the mixture is allowed to react at room temperature (25 ± 3 ° C) for 20 hours to obtain a pass. A compound of formula (III-8).

9) A compound of the formula (III-9) is obtained by reacting a compound of the formula (III-8), sodium chloride and water in a solvent of dimethyl hydrazine in an argon atmosphere at 160 to 175 ° C for 6 hours.

10) The compound of the formula (III-9) is added in a portion of 0 to 10 ° C under a nitrogen atmosphere in an anhydrous atmosphere of 0 to 10 ° C, and 0.5 liter of lithium aluminum hydride is added in portions, and the reaction is carried out at room temperature (25 ± 3 ° C). The compound of the formula (III-10) was obtained by reduction in 2 hours.

11) a compound of the formula (III-10) and 1.2 equivalents of anhydrous pyridine are added to dry dichloromethane in a range of 0 to 5 ° C under a nitrogen atmosphere, and 1.1 equivalents of p-toluenesulfonyl chloride are added in portions to the chamber. The reaction was carried out at a temperature of (25 ± 3 ° C) for 20 hours to obtain a compound of the formula (III-11).

12) Add 2 equivalents of lithium tetrahydrogenate to a solution of the compound of the formula (III-11) in anhydrous tetrahydrofuran under a nitrogen atmosphere at a temperature of 0 to -5 ° C, and raise to room temperature (25 ± 3 ° C). The reaction was carried out for 5 hours to obtain a compound of the formula (Ia).

13) A solution of the compound of the formula (III-10) in methylene chloride is slowly added to the dichloromethane of diethylaminosulfur trifluoride (DAST) under a nitrogen atmosphere at a temperature ranging from -75 to -70 °C. In the solution, after the addition, the temperature was naturally raised to room temperature (25 ± 3 ° C) to obtain a compound of the formula (Ib).

14) A solution of the compound of the formula (III-11) in tetrahydrofuran is slowly added dropwise to a solution of the compound of the formula (IV) in anhydrous ether under a nitrogen atmosphere at a range of -5 to 0 ° C. A solution of lithium copper chloride in tetrahydrofuran was added dropwise at -5 to 0 ° C, and the mixture was stirred at room temperature (25 ± 3 ° C) for 20 hours to give a compound of the formula (Ic).

15) Add 1.5 equivalents of pyridinium chlorochromate (PCC) to a solution of the compound of the formula (III-10) in dichloromethane at 20 to 25 ° C, and add 20 to 25 ° C after the addition. The reaction was carried out for 3 hours to obtain a compound of the formula (III-12).

To a solution of 2 equivalents of the compound of the formula (V) in anhydrous tetrahydrofuran, 2.4 equivalents of potassium t-butoxide are added, and after stirring, the mixture is stirred at -5 to 0 ° C for 0.5 hour, then Further, 1 equivalent of a solution of the compound of the formula (III-12) in tetrahydrofuran is added dropwise at -5 to 0 ° C, and the mixture is reacted at room temperature (25 ± 3 ° C) for 20 hours to obtain a cis-trans isomer of the compound of the formula (Id). a mixture, a cis-trans isomer mixture of a compound of the formula (Id) is subjected to cis-trans isomerization catalyzed by benzenesulfinic acid, and then purified by crystallization to obtain pure A compound of the formula (I-d) in the trans form.

17) Dissolve 2 equivalents of difluorodibromomethane in anhydrous tetrahydrofuran, add 4 equivalents of tris(dimethylamino)phosphine at -75 to -80 ° C, and keep at -75 to -80 ° C after low temperature. The reaction was carried out for 0.5 hour, and the temperature was raised to room temperature (25±3° C.), and 1 equivalent of a tetrahydrofuran solution of the compound of the formula (III-12) was added dropwise, and the reaction was carried out at room temperature (25±3° C.) for 2 hours after completion of the dropwise addition. a compound of formula (Ie).

18) A compound of the formula (VI) is reacted with sodium hydride at 0 to 50 ° C in anhydrous dimethylformamide to give a sodium salt of the compound of the formula (VI), and then added dropwise at 30 to 50 ° C. (III-11) A solution of the compound dimethylformamide, which is reacted at 85 to 90 ° C for 6 to 24 hours to obtain a compound of the formula (If).

A further object of the present invention is to provide a liquid crystal composition comprising one or more liquid crystal compounds of the formula (I).

Preferably, the liquid crystal composition comprises one to five liquid crystal compounds of the formula (I); more preferably, the liquid crystal composition comprises two to four liquid crystal compounds of the formula (I).

According to the liquid crystal composition of the present invention, the additional mixed component may be a generally known mesogen compound, that is, a compound which can form a liquid crystal phase in a pure state or in combination with other components. Some such compounds are mentioned, for example, in DE 1804894 and CN1158602A. Preferably, the liquid crystal composition further comprises at least one liquid crystal compound of the formula (II): Wherein R ₃ and R _{4 are the} same or different and each independently represents -H, -F, -Cl, -CN, -NCS, -SCN, -OCN, -NCO, -OCHCF ₂ , 1-20 carbon atoms At least one halogen-substituted or unsubstituted linear or branched alkyl or alkoxy group, or a linear or branched alkenyl or olefinic oxygen having 2 to 20 carbon atoms substituted or unsubstituted with at least one halogen a base wherein at least one of _-3 - _-2 - -S-, -SiH ₂ -, -CH=CH-, -C≡C-, -CF=CF in R ₃ and R ₄ -, -CH=CF-, , -COO- or -OCO-substitution, provided that the heteroatoms are not directly connected to each other; B ₁ , B ₂ , B ₃ and B _{4 are the} same or different and each independently represents , 1,4-phenylene, 2,3-difluoro-1,4-phenylene, 3-fluoro-1,4-phenylene, 2-chloro-3-fluoro-1,4-benzene Base, 2-fluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, 3,5-difluoro-1,4-phenylene, indole-2,5 -diyl, acridine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl or 1,2,3,4-tetrahydronaphthalene-2,6- Two bases, where or H in can be independently replaced by CN or halogen; One or two non-adjacent -CH ₂ - may be replaced by -O- or -S-, Any one or more of H may be independently replaced by F; One or two non-adjacent -CH- in the middle may be replaced by N, Any one of the preceding one or more may be independently replaced by F; One or two non-adjacent -CH ₂ - in the middle may be replaced by O, Any one or more of H may be independently substituted by F; Y ₁ , Y ₂ , Y ₃ and Y _{4 are the} same or different and each independently represents -OCO-, -COO-, -CF ₂ O-, - CH ₂ O-, -OCH ₂ -, -CH ₂ CH ₂ -, -CF ₂ CH ₂ -, -CF=CF-, -CH=CH-, -CH(CH ₃ )CH ₂ -, -CH ₂ CH (CH ₃ )-, -(CH ₂ ) ₃ O-, -O(CH ₂ ) ₃ -, -COS-, -SCO-, -CH=CF-, -C ₂ F ₄ -, -(CH ₂ ) ₄ -, -C ₄ F ₈ -, -OCF ₂ CF ₂ O-, -CF ₂ CF ₂ CF ₂ O-, -CH ₂ CH ₂ CF ₂ O-, -CH ₂ CF ₂ OCH ₂ -, -CH= CHCF ₂ O-, -CF ₂ OCH=CH-, -CF ₂ OCF=CH-, -CF ₂ OCH=CF-, -CF=CFCF ₂ O-, -CF ₂ OCF=CF-, -CH=CHCH ₂ CH ₂ -, -C ₂ H ₄ OCH ₂ -, -CH ₂ CH=CHCH ₂ -, -OCH ₂ CH ₂ CH ₂ -, -CF=CF-CF=CF-, -C≡C-CF=CF- , -C≡C-CF=CF-C≡C-, -CF=CF-C≡C-CF=CF-, -C≡C-CF ₂ O-, -C≡C- or a single bond, wherein Any one of Y ₁ and Y ₂ -CH ₂ - may be substituted by -SiH ₂ -; a, b, c and d are the same or different and each independently represents 0, 1 or 2. When a is 2, two B ₁ and Y ₁ are the same or different; when b is 2, two B ₂ and Y ₂ are the same or different; when c is 2, two B ₃ and Y ₃ are each The same or different; and when d is 2, the two B ₄ and Y ₄ are the same or different.

The liquid crystal compound of the formula (II) is represented by

Preferably, the total weight of the liquid crystal composition is 100% by weight, The compound of the formula (I) is used in an amount ranging from 5 to 50% by weight, and the compound of the formula (II) is used in an amount ranging from 50 to 95% by weight; more preferably, the compound of the formula (I) is used in an amount ranging from 10 to 10 30 wt%, and the compound of the formula (II) is used in an amount ranging from 70 to 90% by weight.

A further object of the present invention is to provide a novel liquid crystal compound containing a bicyclo[3.3.0]oct-7-ene structure which is suitable as a composition of a liquid crystal medium and can be applied to a liquid crystal element containing a liquid crystal medium such as TN, Display mode liquid crystal elements such as STN, TFT, VA, ECB, OCB, LCP, PDLC, BiNem, LC LENS, FFS, and IPS.

The novel liquid crystal compound containing a bicyclo[3.3.0]oct-7-ene structure provided by the invention has good chemical and physical properties, has lower viscosity than other corresponding liquid crystal materials, and has larger optical anisotropy and Large dielectric anisotropy.

Example

The invention will now be described in connection with specific embodiments. It is to be understood that the following examples are illustrative of the invention and are not intended to limit the invention. Other combinations and various modifications within the inventive concept can be made without departing from the spirit or scope of the invention.

For ease of expression, in the following examples, the group structure of the liquid crystal compound is represented by the codes listed in Table 1:

Take a compound of the following structural formula as an example: The structural formula is expressed by the code listed in Table 1, and can be expressed as: 3PUQUF, where Q represents difluoromethyloxy; in the code, C represents a cyclohexane group; U in the code represents 2, 6-Difluoro-1,4-phenylene.

Example 1

The synthesis method of the prepared compound HCLC- 06 is as follows:

HCLC -06-12 reference EP1160251 synthesis

The specific synthesis steps are as follows:

1) Synthesis of HCLC -06-11

Under a nitrogen atmosphere, a 307 g of diethyl malonate, 5 L of anhydrous tetrahydrofuran, 459 g of HCLC-06-12, 18.4 g of Pd(dba) ₂ (bis(di-benzylideneacetone)palladium), 12.9 g were placed in a 10 L three-necked flask. P(t-Bu) ₃ and 800g K ₃ PO ₄ , reacted at 65 to 70 ° C for 8 hours, and the reaction solution was transferred to a 5 L single-mouth bottle and concentrated by rotation to obtain a crude product, dissolved in 4 L of dichloromethane, filtered, and used for organic phase. Washed with 1 L of 1M diluted hydrochloric acid, washed with 1 L of saturated sodium bicarbonate solution, and dried and concentrated with methylene chloride to give 625 g of brownish oil, and the column was chromatographed with PE:EA=8:1 The liquid was combined and concentrated under reduced pressure using a rotary concentrator to afford 497.5 g of pale yellow oil ( HCLC -06-11 ), purity: 97.6%, yield: 85%.

2) Synthesis of HCLC -06-10

497.5 g of HCLC -06-11 was dissolved in anhydrous tetrahydrofuran, and 133 g of lithium tetrahydrogenate was added in portions under a nitrogen atmosphere at a range of 0 to 5 ° C, and the reaction was carried out at room temperature (25 ± 3 ° C) for 6 hours. 100 g of ethyl acetate was added dropwise, and 140 g of water was added dropwise, and the metaaluminate was removed by filtration. The filtrate was concentrated by spin to obtain 379 g of a pale yellow oil, and subjected to column chromatography using a PE:EA=1:1 extract. The mixture was extracted with ethyl acetate, and the TLC-free chromatographic solution was combined. The solvent was concentrated under reduced pressure using a rotary concentrator to obtain 350.5 g of a colorless transparent liquid ( HCLC -06-10), purity: 98.7%, yield: 92.1% .

3) Synthesis of HCLC-06-09

Add 100.5g of HCLC -06-10, 4L of chloroform to a 10L three-necked flask, install a dry, reflux and tail gas absorption device, add 739g of phosphorus tribromide in 500mL of chloroform solution at 0 to 5 °C with stirring. After that, the mixture was stirred at room temperature (25±3° C.) for 30 minutes, and refluxed for 6 hours. TLC was monitored, the reaction was completed, the heating was stopped, and the mixture was naturally cooled to room temperature (25±3° C.), and the reaction liquid was slowly added to 4 L. Saturated sodium phosphate in ice water solution, and then adjusted to pH 14 with 1M (mol / L) sodium hydroxide solution, transferred to a separatory funnel, and the aqueous layer was extracted three times with 500 mL of chloroform, and the organic layer was combined. The organic layer was washed twice with saturated aqueous sodium hydrogen sulfate and dried over anhydrous sodium sulfate. The crude product was subjected to column chromatography using petroleum ether, and the solvent was combined, and the solvent was concentrated under reduced pressure to give 460 g of white solid ( HCLC -06-09), purity: 96.7%, yield: 90.5%.

4) Synthesis of HCLC -06-08

In a 10 L three-necked flask, 162 g of dimethyl succinate, 3 L of anhydrous tetrahydrofuran, 270 mL of hexamethylphosphiniumamine, argon gas protection and the temperature was lowered to -75 ° C, and 1 L of 1 M lithium diisopropylamide solution was added dropwise. After the completion of the dropwise addition, the mixture was stirred at -80 to -75 ° C for 45 minutes, and then 460 g of a solution of HCLC- 06-09 in 500 mL of anhydrous tetrahydrofuran was added dropwise at -80 to -75 ° C, and the mixture was added dropwise, and the mixture was stirred at -80 to -75 ° C for 2 hours. The mixture was naturally warmed to room temperature (25 ± 3 ° C) for 20 hours; the reaction solution was poured into 500 mL of saturated aqueous ammonium chloride solution, transferred to a separating funnel, and the aqueous layer was extracted three times with 300 mL of ethyl acetate. The mixture was washed twice with aq. aq. sodium hydrogen sulfate, and then evaporated and evaporated. The crude product was subjected to column chromatography using a PE:EA=5:1 extract, and the chromatographic solution was combined, and the solvent was concentrated under reduced pressure using a rotary concentrator to obtain 184.5 g of pale yellow solid ( HCLC -06-08) ), purity: 94.7%, yield: 76%.

5) Synthesis of HCLC -06-07

Under an argon atmosphere, 145 g of cyclohexylisopropylamine was added dropwise to a solution of 415 mL of 2.5 M n-butyllithium in 300 mL of tetrahydrofuran under an argon atmosphere, and the mixture was stirred for 0.5 hour while adding 184.5 g. In a solution of HCLC -06-08 in 300 mL of tetrahydrofuran, then add 119.5 g of iodine in 300 mL of tetrahydrofuran solution at -80 to -75 ° C. After the dropwise addition, naturally rise to room temperature (25 ± 3 ° C), and then drip. 400 mL of 2M dilute hydrochloric acid was added, 400 mL of ethyl acetate and 300 mL of saturated sodium chloride solution were added, and the mixture was stirred for 15 minutes, and the aqueous layer was extracted with 300 mL of ethyl acetate. The organic layer was combined and washed twice with saturated aqueous sodium hydrogen carbonate. The organic layer was dried over anhydrous sodium sulfate (100 g), and then evaporated. The crude product was recrystallized twice from 250 mL of dry ethanol to afford white powdery solid HCLC -06-07 120 g, purity: 98.9%, yield: 65.4%.

6) Synthesis of HCLC-06-06

120g of HCLC -06-07 was dissolved in 800 mL of anhydrous tetrahydrofuran. Under nitrogen protection, 29 g of lithium tetrahydroaluminum was added in portions ranging from 0 to -5 ° C, and then reacted at 0 to -5 ° C for 1 hour, stirring well. 20 g of ethyl acetate was added dropwise, 30 g of water was added dropwise, and the metaaluminate was removed by filtration. The filtrate was concentrated by rotation to obtain 379 g of a pale yellow oil, which was subjected to column chromatography using a PE:EA=1:1 extract. The mixture was extracted with ethyl acetate, and the residue-free chromatography was combined, and the solvent was concentrated under reduced pressure to give 94.5 g of white solid, and then recrystallized twice with 25 mL of ethyl acetate and 100 mL of petroleum ether to give 66 g of white solid. ( HCLC- 06-06), purity: 99.3%, yield: 64.4%.

7) Synthesis of HCLC-06-05

66 g of compound HCLC-06-06, 114 g of triphenylphosphine and 29.5 g of imidazole were dissolved in 600 mL of dry dichloromethane, and a solution of 69.5 g of bromine in 150 mL of dichloromethane was added under a nitrogen atmosphere at a temperature of 0 to 5 °C. Raise to 30 ° C for 4 hours, the reaction solution is poured into 300 mL of saturated sodium bicarbonate solution, liquid separation, the organic phase is washed twice with 300 mL of deionized water, dried, concentrated by rotation, and the crude product is then extracted with petroleum ether. Column chromatography and concentration gave 71 g of white solid HCLC -06-05, purity: 98.7%, yield: 78.5%.

8) Synthesis of HCLC-06-04

In a solvent of anhydrous tetrahydrofuran, a solution of 25 g of diethyl malonate in 100 mL of tetrahydrofuran was added dropwise to a solution of 345 mL of 1 M lithium diisopropylamide in tetrahydrofuran under an argon atmosphere at a temperature of -80 to -75 °C. Then, a solution of 71 g of compound HCLC-06-05 in 150 mL of tetrahydrofuran was added dropwise at -80 to -75 ° C, and the mixture was allowed to react at room temperature (25 ± 3 ° C) for 20 hours, and then 400 mL of a saturated ammonium chloride solution was added thereto. The aqueous layer was extracted three times with 300 mL of ethyl acetate. The organic layer was combined and washed twice with saturated aqueous sodium chloride, and dried over anhydrous sodium sulfate. The crude product was subjected to column chromatography with PE:EA=6:1 extract, and the chromatographic solution was combined with a non- doped point. The solvent was concentrated under reduced pressure with a rotary concentrator to obtain 52.5 g of pale yellow liquid HCLC -06-04, purity. : 98.7%, yield: 74.4%.

9) Synthesis of HCLC -06-03

52.5g of compound HCLC -06-04, 53.5g of sodium chloride and 40g of water in 400mL of dimethyl hydrazine solvent, under argon atmosphere, reflux reaction for 6 hours, the reaction is completed, in an argon atmosphere oil bath 80 to The solvent was evaporated to dryness under reduced pressure at 90 ° C, and the crude product was added to 100 mL of toluene and 50 mL of water, and the mixture was washed with water, and the organic phase was concentrated with a rotary concentrator to obtain 46 g of pale yellow liquid, and the crude product was subjected to PE:EA=8:1 extract. Column chromatography, combining the chromatographic solution without impurities, and concentrating the solvent under reduced pressure with a rotary concentrator to obtain 31.5 g of pale yellow liquid HCLC -06-03, purity: 97.6% (cis-trans isomer 1:1), Yield: 71.3%.

10) Synthesis of HCLC -06-02

31.5 g of compound HCLC -06-03 In 250 mL of anhydrous tetrahydrofuran, 3 g of lithium tetrahydrogenate was added in portions under a nitrogen atmosphere at a range of 0 to 10 ° C, and the reaction was carried out at room temperature (25 ± 3 ° C) for 12 hours. Slowly add sodium sulfate decahydrate to destroy excess lithium aluminum hydride. After the solid in the reaction system turns yellowish white, stop adding sodium sulfate decahydrate. Filtration under reduced pressure, the filter cake was washed three times with 150 mL of ethyl acetate. The organic phase was combined and concentrated to give 29 g of crude product. The crude product was subjected to column chromatography with PE:EA=1:1 extract, and then washed with ethyl acetate. The TLC impurity-free chromatography liquid was combined, and the solvent was concentrated under reduced pressure with a rotary concentrator to obtain 27 g of a white solid, which was recrystallized three times with 20 mL of petroleum ether and 3 mL of ethanol to obtain 7.5 g of white solid HCLC -06-02, purity. : 97.4%, yield: 26.8%.

11) Synthesis of HCLC -06-01

2.5 g of compound HCLC -06-02 and 0.7 g of anhydrous pyridine were added to 1.7 g of p-toluenesulfonyl chloride in a range of 0 to 5 ° C under nitrogen atmosphere in 20 mL of dry dichloromethane, and raised to room temperature (25 ± 3). The reaction was carried out for 20 hours at ° C., and the reaction mixture was washed with water and evaporated to give 3.9 g of pale yellow solid. The crude product was recrystallized twice with 15 mL of ethanol and 2 mL of ethyl acetate to afford white solid HCLC -06-01 3.2 g, HPLC: 99. Yield: 88.9%.

12) Synthesis of HCLC- 06

Under a nitrogen atmosphere, in a range of -5 to 0 ° C, a commercially available 19 mL of 1 M (mol/L) ethylmagnesium bromide tetrahydrofuran solution was slowly added dropwise to 3.2 g of compound HCLC- 06-01 in 50 mL of anhydrous ether. After the dropwise addition, 2 mL of 1M fresh copper chloride tetrahydrofuran solution was added dropwise at -5 to 0 ° C. After the completion of the dropwise addition, the mixture was stirred at room temperature (25 ± 3 ° C) for 20 hours, and stirred with 20 mL of a saturated ammonium chloride solution. The liquid phase was extracted twice with 20 mL of diethyl ether. The organic phase was combined and concentrated to give a pale yellow solid. The crude product was subjected to column chromatography with petroleum ether to give 1.72 g of white solid. The compound HCLC -06 1.34 g was obtained, purity: 99.8%, yield: 75.3%.

GC-MS: EI ion source m/z: 356.3.

¹ H NMR (300MHz, CDCl ₃ ), δ (ppm): 7.78-7.42 (m, 4H), 7.31-7.23 (m, 2H), 3.58-3.30 (m, 1H), 2.76-2.49 (m, 4H) , 2.44-2.16 (m, 2H), 2.09-1.75 (m, 3H), 1.70-1.42 (m, 2H), 1.33-1.17 (m, 2H), 0.89 (t, J = 13.0Hz, 3H).

Example 2

The synthesis method of the prepared compound HCLC-06A is as follows:

To a solution of 1 g of compound HCLC- 06-01 in 20 mL of anhydrous tetrahydrofuran under a nitrogen atmosphere at a temperature of 0 to -5 ° C, 0.15 g of lithium aluminum hydride was added, and the mixture was allowed to react at room temperature (25 ± 3 ° C) for 5 hours. Slowly add sodium sulfate decahydrate to destroy excess lithium aluminum hydride. After the solid in the reaction system turns yellowish white, stop adding sodium sulfate decahydrate. Filtration under reduced pressure, the filter cake was washed three times with 10 mL of ethyl acetate. The organic phase was combined and concentrated to give 29 g of crude product. The crude product was subjected to column chromatography with petroleum ether to give 0.48 g of white solid, HCLC -06A, purity: 99.7% , Yield: 72.9%.

GC-MS: EI ion source m/z: 328.2.

¹ H NMR (300MHz, CDCl ₃ ), δ (ppm): 7.78-7.42 (m, 4H), 7.31-7.23 (m, 2H), 3.58-3.30 (m, 1H), 2.76-2.49 (m, 4H) , 2.44 - 2.16 (m, 2H), 2.09 - 1.75 (m, 3H), 0.86 (d, J = 6.8 Hz, 3H).

Example 3

The synthesis method of the prepared compound HCLC- 06B is as follows:

Under nitrogen protection, 1 g of compound HCLC- 06-02 in 10 mL of dichloromethane was slowly added to 0.7 g of diethylaminosulfur trifluoride (DAST) in 20 mL of dichloromethane at a temperature of -75 to -70 °C. In the solution, after the addition, naturally rise to room temperature (25 ± 3 ° C), add 10mL saturated ammonium chloride solution, separate the liquid, the organic phase is washed twice with 10mL saturated sodium bicarbonate solution, dried, concentrated to give 0.9g white The solid crude product was recrystallized twice with 2mL of ethanol, to give 0.65g of white solid, HCLC -06B, purity: 99.6%, yield: 65%.

GC-MS: EI ion source m/z: 346.2.

Example 4

The synthesis method of the prepared compound HCLC- 06C is as follows:

1) Synthesis of HCLC-06C-01

3.7 g of PCC was added in portions to 4 g of compound HCLC- 06-06 in 50 methylene chloride at 20 to 25 ° C. After the addition, the reaction was carried out at 20 to 25 ° C for 3 hours, and the reaction solution was subjected to column chromatography. Concentration gave 4.1 g, and the crude product was recrystallized twice from 10 mL of isopropyl alcohol to give 3.2 g of white solid HCLC -06 C </ RTI></RTI></RTI> purity: 97.4%, yield: 80.5%.

2) Synthesis of HCLC-06C

To a solution of 4.3 g of triethylphosphonium bromide in 50 mL of anhydrous tetrahydrofuran, 1.56 g of potassium t-butoxide was added at a temperature of -5 to 0 ° C. After the addition, the mixture was stirred at -5 to 0 ° C for 0.5 hour, and then 2 g of compound HCLC- 06C-01 in 20 mL of tetrahydrofuran solution was added dropwise at -5 to 0 ° C. After the completion of the dropwise addition, the reaction was carried out at room temperature (25 ± 3 ° C) for 20 hours, and the reaction liquid was concentrated, and the column was layered with petroleum ether. It was concentrated and concentrated to obtain 1.9 g of a pale yellow oil; the crude product was added to 10 mL of petroleum ether, and 0.3 g of sodium benzenesulfinate and 2 mL of 1 M diluted hydrochloric acid were added under a nitrogen atmosphere, and the mixture was reacted at 60 ° C for 3 hours in a water bath, and 5 mL of saturated carbonic acid was added thereto. The sodium solution and 20 mL of petroleum ether were separated, and the organic phase was washed twice with 20 mL of water. The organic phase was dried, and then subjected to column chromatography, and concentrated to give 1.6 g of crude product, and then recrystallized three times with 5 mL of ethanol to obtain 0.6 g of white solid. HCLC- 06C, purity: 99.8%, yield: 29%.

GC-MS: EI ion source m/z: 354.3.

Example 5

The synthesis method of the prepared compound HCLC- 06D is as follows:

1.47 g of difluorodibromomethane was dissolved in 20 mL of anhydrous tetrahydrofuran, and 2.28 g of tris(dimethylamino)phosphine 10 mL of anhydrous tetrahydrofuran solution was added dropwise at -75 to -80 ° C, and kept at -75 to - after completion of the dropwise addition. The reaction was carried out at 80 ° C for 0.5 hour, and the temperature was raised to room temperature (25 ± 3 ° C). 1.2 g of the compound HCLC -06C-01 in 10 mL of tetrahydrofuran solution was added dropwise, and the reaction was carried out at room temperature (25 ± 3 ° C) for 2 hours after the dropwise addition. 5 mL of 2M dilute hydrochloric acid and 20 mL of ethyl acetate were added to the reaction mixture, and the mixture was separated, and the aqueous phase was extracted twice with 10 mL of ethyl acetate. The organic phase was combined, washed three times with saturated sodium hydrogen carbonate solution, dried and concentrated The solid and the crude product were subjected to column chromatography eluting with petroleum ether to give 1 g of white solid, and then recrystallized twice with 2 mL of ethanol to give 0.5 g of white solid HCLC -06D, purity: 99.8%, yield: 37.9%.

GC-MS: EI ion source m/z: 376.2.

Example 6

The synthesis method of the prepared compound HCLC- 06E is as follows,

HCLC -06E-12 is synthesized by reference EP 1160251.

Compound HCLC- 06E was obtained by the procedure of Example 1 by substituting HCLC -06E-12 for HCLC -06-12.

GC-MS: EI ion source m/z: 374.3.

¹ H NMR (300MHz, CDCl ₃ ), δ (ppm): 7.75 (dd, J = 14.9, 10.0 Hz, 1H), 7.47-7.16 (m, 4H), 3.58-3.30 (m, 1H), 2.76-2.49 (m,4H),2.44-2.16(m,2H),2.09-1.75(m,3H),1.70-1.42(m,2H),1.33-1.17(m,2H),0.89(t, J =13.0Hz , 3H).

Example 7

The synthesis method of the prepared compound HCLC- 06H is as follows:

HCLC -06H-12 is synthesized by reference WO2009139330.

Compound HCLC- 06H was obtained by the procedure of Example 1 by substituting HCLC -06H-12 for HCLC -06-12.

GC-MS: EI ion source m/z: 552.3.

¹ H NMR (300MHz, CDCl ₃ ), δ (ppm): 7.75 (dd, J = 14.9, 10.0 Hz, 1H), 7.28-7.08 (m, 3H), 6.95-6.86 (m, 3H), 3.62-3.29 (m, 1H), 2.75-2.49 (m, 4H), 2.41-2.16 (m, 2H), 2.11 - 1.80 (m, 3H), 1.61-1.49 (m, 2H), 1.38-1.13 (m, 2H) , 0.89 (t, J = 13.0 Hz, 3H).

The following Example 8 is a measurement result of the characteristics of the liquid crystal composition of the present invention.

The shorthand code of the test method in the following examples is as follows:

Cp (°C): Clarification point (nematic-isotropic phase transition temperature)

η (mPa.s): flow viscosity (20 ° C, unless otherwise stated)

△n: optical anisotropy (589 nm, 20 ° C)

△ ε: dielectric anisotropy (1 kHz, 25 ° C)

Example 8

Table 2 shows the liquid crystal compositions formulated with HCLC- 06, HCLC- 06E and HCLC- 06H and the corresponding properties obtained.

Table 2 Liquid crystal composition formulation and characteristic measurement results

In summary, the liquid crystal compound containing the bicyclo[3.3.0]oct-7-ene structure of the general formula (I) of the present invention has a novel structure and has a low viscosity, a large optical anisotropy and a large Dielectric anisotropy. The liquid crystal composition of the present invention has an effect of using the liquid crystal compound of the formula (I) and can be applied to liquid crystal elements of various display modes, so that the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the patent application and the patent specification of the present invention, All remain within the scope of the invention patent.

Claims (10)

A liquid crystal compound containing a bicyclo[3.3.0]oct-7-ene structure having the structure of the general formula (I): Wherein R ₁ represents a linear or branched alkyl or alkoxy group of _{1 to} 20 carbon atoms which is substituted or unsubstituted with at least one halogen, wherein at least one -CH ₂ - in the R ₁ may be - O-, -S-, -SiH ₂ -, -CH=CH-, -C≡C-, -CF=CF-, -CH=CF-, -COO- or -OCO-substitution, provided that the hetero atom Not directly connected to each other, and the O, S and Si atoms are not directly connected to the ring; R ₂ represents -H, -F, -Cl, -CN, -NCS, -SCN, -NCO, Or a straight or branched alkyl or alkoxy group having 1 to 20 carbon atoms substituted or unsubstituted with at least one halogen, wherein at least one -CH ₂ - in the R ₂ may be -O-, - S-, -SiH ₂ -, -CH=CH-, -C≡C-, -CF=CF- or -CH=CF-substitution, provided that the heteroatoms are not directly connected to each other; ring A ₁ represents , or ; Rings A ₂ , A ₃ , and A _{4 are the} same or different and each independently represents , , , or The cyclic structure represented by the rings A ₁ , A ₂ , A ₃ , and A ₄ may also conform to at least one of the following a), b), c), and d): a) the ring One or more hydrogen atoms in the structure may be -D, -F, -Cl, -CN, -CF ₃ , -OCF ₃ , -CH ₂ F, -OCH ₂ F, -CF ₂ H, -OCF ₂ H , -OCH ₃ or -CH ₃ substituted; b) one or more -CH ₂ - in the cyclic structure is substituted by -O-, -SiH ₂ -, -S- or -CO-, provided that the heteroatoms are Not directly connected; c) in the cyclic structure, one or more -CH- in the aromatic ring structure may be substituted by N; d) one or more of the cyclic structures Can be Substituted; Z ₁ represents -CF ₂ O-, -CH ₂ O-, -CH ₂ CH ₂ -, -CH ₂ CF ₂ -, -CF ₂ CH ₂ -, -(CH ₂ ) ₄ -, -CH ₂ CH ₂ CF ₂ O-, -CH ₂ CF ₂ OCH ₂ -, -C ₂ H ₄ OCH ₂ -, -CH ₂ CH ₂ CH ₂ O- or a single bond; Z ₂ , Z ₃ and Z _{4 are the} same or different, each Independently represents a single bond, -CF ₂ O-, -CH ₂ O-, -CH ₂ CH ₂ -, -CF ₂ CH ₂ -, -CF=CF-, -CH=CH-, -CH=CF-, -C ₂ F ₄ -, -(CH ₂ ) ₄ -, -C ₄ F ₈ -, -OCF ₂ CF ₂ O-, -CF ₂ CF ₂ CF ₂ O-, -CH ₂ CH ₂ CF ₂ O-, -OCF ₂ CF ₂ CF ₂ -, -CH ₂ CF ₂ OCH ₂ -, -CH=CHCF ₂ O-, -CF ₂ OCH=CH-, -CF ₂ OCF=CH-, -CF ₂ OCH=CF-, -CF=CFCF ₂ O-, -CH=CFCF ₂ O-, -CF ₂ OCF=CF-, -CH=CHCH ₂ CH ₂ -, -C ₂ H ₄ OCH ₂ -, -CH ₂ CH=CHCH ₂ - , -OCH ₂ CH ₂ CH ₂ -, -CF=CF-CF=CF-, -C≡C-CF=CF-, -C≡C-CF=CF-C≡C-, -CF=CF-C ≡C-CF=CF-, -C≡C-CF ₂ O- or -C≡C-, wherein any one of the linking groups of Z ₂ , Z ₃ and Z ₄ -CH ₂ - can be - SiH ₂ -substituted; m, n and p are the same or different and each independently represents 0, 1 or 2. When m is 2, two Z ₂ and two A ₂ are the same or different; when n is 2, two Z ₃ and two A ₃ are the same or different; when p is 2, two Z ₄ and The two A ₄ are each the same or different. The liquid crystal compound according to claim 1, wherein m, n and p are the same or different, each independently represents 0, 1 or 2, and m+n+p 4. The liquid crystal compound according to claim 1, wherein the liquid crystal compound is represented by or Wherein R ₁ represents a straight or branched alkyl or alkoxy group of _{1 to} 5 carbon atoms which is substituted or unsubstituted with at least one halogen, wherein at least one -CH ₂ - in the R ₁ may be - O-, -S-, -SiH ₂ -, -CH=CH-, -C≡C-, -CF=CF-, -CH=CF-, -COO- or -OCO-substitution, provided that the hetero atom Not directly connected to each other, and the O, S and Si atoms are not directly bonded to the ring; R ₂ represents -H, -F, -CN and a straight or branched chain of 1-5 carbon atoms substituted or unsubstituted by at least one halogen An alkyl or alkoxy group of a chain wherein at least one -CH ₂ - in the R ₂ may be -O-, -CH=CH-, -C≡C-, -CF=CF- or -CH=CF a substitution, provided that the heteroatoms are not directly bonded to each other; Z ₁ represents -CH ₂ O-, -CH ₂ CH ₂ -, -CH ₂ CF ₂ -, -CF ₂ CH ₂ -, -(CH ₂ ) ₄ - , -CH ₂ CH ₂ CF ₂ O-, -CH ₂ CF ₂ OCH ₂ -, -CH ₂ CH ₂ CH ₂ O- or a single bond; Z ₂ , Z ₃ , and Z _{4 are the} same or different and each independently represents -CF ₂ O-, -CH ₂ O-, -CH ₂ CH ₂ -, -CF=CF-, -CH=CH-, -C ₂ F ₄ -, -OCF ₂ CF ₂ O-, -CF=CFCF ₂ O-, -C≡C- or a single bond; L ₁ ~ L ₄ each independently represent -H, -F or -CH ₃ ; L ₅ ~L ₁₆ each independently represents -H, -F, -OCF ₂ H, -CH ₃ , -OCH ₃ , -OCF ₃ or -CF ₃ . A liquid crystal composition comprising at least one of claims 1 to 3 The liquid crystal compound described in the above. The liquid crystal composition according to claim 4, wherein the liquid crystal composition comprises one to five liquid crystal compounds according to any one of claims 1 to 3. The liquid crystal composition according to claim 4, wherein the liquid crystal composition further comprises at least one liquid crystal compound of the formula (II): Wherein R ₃ and R _{4 are the} same or different and each independently represents -H, -F, -Cl, -CN, -OCHCF ₂ , a straight chain of 1-20 carbon atoms substituted or unsubstituted with at least one halogen or a branched alkyl or alkoxy group, or a linear or branched alkenyl or alkenyloxy group having 2 to 20 carbon atoms substituted or unsubstituted with at least one halogen, wherein R ₃ and R _{4 are} At least one -CH ₂ - may be substituted by -O-, -S-, -SiH ₂ -, -CH=CH-, -C≡C-, -CF=CF- or -CH=CF-, provided that The heteroatoms are not directly connected to each other; B ₁ , B ₂ , B ₃ and B _{4 are the} same or different and each independently represents , , 1,4-phenylene, 2,3-difluoro-1,4-phenylene, 3-fluoro-1,4-phenylene, 2-chloro-3-fluoro-1,4-benzene Base, 2-fluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, 3,5-difluoro-1,4-phenylene or naphthalene-2,6- Two bases, where or H in can be independently replaced by CN or halogen; One or two of the non-adjacent -CH ₂ - may be replaced by -O- or -S-, Any one or more of H may be independently replaced by F; One or two non-adjacent -CH- in the middle may be replaced by N, Any of the above H or any of H may be independently substituted by F;; Y ₁ , Y ₂ , Y ₃ and Y _{4 are the} same or different and each independently represents -CF ₂ O-, -CH ₂ O-, - OCH ₂ -, -CH ₂ CH ₂ -, -CF ₂ CH ₂ -, -CH(CH ₃ )CH ₂ -, -CH ₂ CH(CH ₃ )-, -(CH ₂ ) ₃ O-, -O ( CH ₂ ) ₃ -, -C ₂ F ₄ -, -(CH ₂ ) ₄ -, -C ₄ F ₈ -, -OCF ₂ CF ₂ O-, -CF ₂ CF ₂ CF ₂ O-, -CH ₂ CH ₂ CF ₂ O-, -CH ₂ CF ₂ OCH ₂ -, -C ₂ H ₄ OCH ₂ -, -OCH ₂ CH ₂ CH ₂ - or a single bond, wherein any one of Y ₁ and Y ₂ - CH ₂ - may be substituted by -SiH ₂ -; a, b, c and d are the same or different and each independently represents 0, 1 or 2. When a is 2, two B ₁ and Y ₁ are the same or different; when b is 2, two B ₂ and Y ₂ are the same or different; when c is 2, two B ₃ and Y ₃ are each The same or different; and when d is 2, the two B ₄ and Y ₄ are the same or different. The liquid crystal composition according to claim 6, wherein the compound of the formula (I) is used in an amount ranging from 5 to 50% by weight based on the total weight of the liquid crystal composition, and the compound of the formula (II) The amount ranges from 50 to 95% by weight. The liquid crystal composition according to claim 6, wherein the compound of the formula (I) is used in an amount ranging from 10 to 30% by weight based on the total weight of the liquid crystal composition, and the compound of the formula (II) The amount ranges from 70 to 90% by weight. The liquid crystal composition according to claim 6, wherein the liquid crystal compound of the formula (II) is represented by A liquid crystal display comprising the liquid crystal composition according to any one of claims 4 to 9.