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

Abstract

The present invention provides a liquid crystal compound of general formula F, a liquid crystal composition containing the liquid crystal compound, and a liquid crystal display device containing the liquid crystal composition. The liquid crystal compound of the present invention has a larger clearing point, a larger optical anisotropy, and a comparable or larger absolute value of dielectric anisotropy while maintaining an appropriate rotational viscosity, so that the liquid crystal composition containing the compound of general formula F of the present invention has a larger optical anisotropy, a smaller rotational viscosity, a higher VHR (UV), and a longer low-temperature storage time while maintaining an appropriate clearing point, an appropriate absolute value of dielectric anisotropy, and an appropriate VHR (initial), and the liquid crystal display device containing the liquid crystal composition of the present invention has a better contrast, a faster response speed, a higher reliability, and a better low-temperature storage stability.

Description

Technical Field

[0001] The present invention relates to the field of liquid crystals, and in particular to a liquid crystal compound, a liquid crystal composition comprising the liquid crystal compound, and a liquid crystal display device comprising the liquid crystal composition. Background Art

[0002] Liquid crystal display elements can be used in various household appliances represented by clocks and electronic calculators, measuring machines, automotive panels, word processors, computers, printers, televisions, etc. According to the type of display mode, liquid crystal display elements can be divided into PC (phase change), TN (twist nematic), STN (super twisted nematic), ECB (electrically controlled birefringence), OCB (optically compensated bend), IPS (in-plane switching), VA (vertical alignment), etc. According to the driving method of the element, liquid crystal display elements can be divided into PM (passive matrix) type and AM (active matrix) type. PM is divided into static and multiplex types. AM is divided into TFT (thin film transistor), MIM (metal insulator metal) and other types. TFT types include amorphous silicon and polycrystalline silicon. The latter is divided into high temperature type and low temperature type according to the manufacturing process. According to the type of light source, liquid crystal display elements can be divided into reflective type using natural light, transmissive type using background light, and semi-transmissive type using both natural light and backlight.

[0003] The liquid crystal display element contains a liquid crystal composition having a nematic phase, and the liquid crystal composition has appropriate characteristics. By improving the characteristics of the liquid crystal composition, an AM element with good characteristics can be obtained. The relationship between the characteristics of the liquid crystal composition and the characteristics of the AM element is summarized in the following Table 1.

[0004] Table 1. Characteristics of liquid crystal composition and AM element

[0005] serial number Characteristics of Liquid Crystal Compositions Characteristics of AM components 1 Nematic phase has a wide temperature range Wide temperature range 2 Low viscosity Short response time 3 Optical anisotropy is appropriate High contrast 4 The absolute value of positive or negative dielectric anisotropy is large Low threshold voltage, low power consumption, high contrast 5 Larger specific resistance High voltage holding rate and contrast ratio 6 UV and heat stable Long life 7 Large elastic constant High contrast and short response time

[0006] In the application of liquid crystal display devices, the contrast has a critical impact on visual effects. Generally speaking, the greater the contrast, the clearer and more eye-catching the image, and the brighter the color; if the contrast is small, the whole picture will be gray. High contrast is very helpful for image clarity, detail expression, and grayscale expression. High-contrast products have advantages in black and white contrast, clarity, integrity, etc. Contrast also has a great impact on dynamic video display effects. Since the light and dark conversion in dynamic images is relatively fast, the higher the contrast, the easier it is for the human eye to distinguish such a conversion process.

[0007] With the improvement of the resolution of liquid crystal displays, 4K and 8K resolution liquid crystal displays are gradually emerging, which in turn requires liquid crystal panels to have a smaller aperture ratio and higher transmittance. Negative liquid crystal compositions have higher transmittance, especially in PSA mode and NFFS mode, where the advantage of high transmittance is more obvious. However, the structure of negative liquid crystals determines that they have a larger rotational viscosity and a smaller voltage holding rate. Therefore, it is urgent to develop a negative liquid crystal compound with a smaller rotational viscosity and a higher voltage holding rate to improve the shortcomings of existing negative liquid crystals and provide a liquid crystal composition that meets market demand.

[0008] Chinese patent application CN1942461A and German patent application DE10101022A1 disclose a liquid crystal compound that can solve the above problems to a certain extent. Chinese patent application CN107973766A performs ring substitution on the terminal structure of such compounds on the basis of the prior art. However, the compounds disclosed so far have the problems of small absolute value of dielectric anisotropy, large rotational viscosity and poor low-temperature miscibility. More seriously, benzofuran and benzothiophene compounds have poor stability under UV. It is well known that liquid crystal panels need to be exposed to a certain degree of UV light during the manufacturing process, and the light amount of ultraviolet light with a wavelength of 365nm is generally about 6000-1000MJ. After being exposed to UV light, the VHR (UV) of traditional benzofuran and benzothiophene compounds is low, which reduces the reliability of the display and produces residual images.

[0009] Therefore, how to obtain a liquid crystal compound and a liquid crystal composition containing the same, so as to solve or partially solve the above problems, is still a problem to be solved urgently in the art. Summary of the invention

[0010] Purpose of the invention: In view of the defects existing in the prior art, the purpose of the present invention is to provide a liquid crystal compound having a larger clearing point, a larger optical anisotropy and a comparable or larger absolute value of dielectric anisotropy while maintaining an appropriate rotational viscosity.

[0011] The present invention also aims to provide a liquid crystal composition comprising the above-mentioned liquid crystal compound, which has a larger optical anisotropy, a smaller rotational viscosity, a higher VHR (UV) and a longer low-temperature storage time while maintaining an appropriate clearing point, an appropriate absolute value of dielectric anisotropy and an appropriate VHR (initial).

[0012] Another object of the present invention is to provide a liquid crystal display device comprising the liquid crystal composition.

[0013] Technical solution: In order to achieve the above invention objectives, the present invention provides a liquid crystal compound of general formula F:

[0014]

[0015] in,

[0016] R F1 represents -H, halogen, a straight or branched alkyl group containing 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, wherein one or more non-adjacent -CH2- in a linear or branched alkyl group containing 1 to 12 carbon atoms may be independently replaced by -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or more -H in the linear or branched alkyl group containing 1 to 12 carbon atoms may be independently replaced by -F or -Cl;

[0017] ring and ring Each independently expresses in One or more -CH2- in the ring may be replaced by -O-, and one or more single bonds in the ring may be replaced by double bonds, wherein One or more -H in the ring may be independently replaced by -CN, -F or -Cl, and one or more -CH= in the ring may be replaced by -N=;

[0018] X F represents -O-, -S-, or -CO-;

[0019] L F1 and L F2 Each independently represents -H, -F, -Cl, -CF3 or -OCF3;

[0020] Z F1 and Z F2Each independently represents a single bond, -O-, -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, -CH2CH2-, -CF2CF2-, -(CH2)4-, -CF2O- or -OCF2-;

[0021] n F1 and n F2 Each independently represents 0, 1 or 2, where n F1 When it indicates 2, the ring can be the same or different, where n F2 When it indicates 2, the ring Can be the same or different, Z F2 can be the same or different; and

[0022] n F3 Represents an integer from 0 to 4.

[0023] In some embodiments of the present invention, preferably, L F1 and L F2 Each independently represents -F or -Cl.

[0024] In some embodiments of the present invention, the compound of formula F is selected from the group consisting of:

[0025]

[0026]

[0027] as well as

[0028] in,

[0029] X F1 and X F2 Each independently represents -CH2- or -O-.

[0030] In some embodiments of the present invention, in order to obtain a larger absolute value of dielectric anisotropy while maintaining an appropriate clearing point, an appropriate optical anisotropy and an appropriate rotational viscosity, it is preferred that X F Means -S-.

[0031] In some embodiments of the present invention, preferably, n F3 represents 0 or 1; further preferably, n F3 Represents 0.

[0032] In some embodiments of the present invention, preferably, Z F1 and ZF2 Each independently represents a single bond, -CH2O- or -OCH2-, and further preferably, Z F1 and Z F2 Both represent single bonds.

[0033] In some embodiments of the present invention, n F1 and n F2 At least one of n represents 0; further preferably, n F1 and n F2 All represent 0.

[0034] In some embodiments of the present invention, preferably, R F1 represents a straight-chain or branched alkyl group containing 1 to 10 carbon atoms, a straight-chain or branched alkoxy group containing 1 to 9 carbon atoms, or a straight-chain or branched alkenyl group containing 2 to 10 carbon atoms; further preferably, R F1 It represents a straight chain or branched chain alkyl group containing 1 to 8 carbon atoms, a straight chain or branched chain alkoxy group containing 1 to 7 carbon atoms, or a straight chain or branched chain alkenyl group containing 2 to 8 carbon atoms.

[0035] In some embodiments of the present invention, in the compounds of formula F-1, F-2, F-3, F-4, F-5, F-6, F-26 and F-27, R F1 It represents a straight-chain or branched alkoxy group having 1 to 7 carbon atoms.

[0036] In some embodiments of the present invention, the compound of formula F-1 is selected from the group consisting of:

[0037]

[0038] as well as

[0039] In some embodiments of the present invention, the compound of formula F-2 is selected from the group consisting of:

[0040] as well as

[0041] In some embodiments of the present invention, the compound of formula F-5 is selected from the group consisting of:

[0042] as well as

[0043] In some embodiments of the present invention, the compound of formula F-6 is selected from the group consisting of:

[0044] as well as

[0045] In some embodiments of the present invention, the compound of formula F-9 is selected from the group consisting of:

[0046] as well as

[0047] The liquid crystal compound of the present invention has a large absolute value of dielectric anisotropy, and is particularly suitable for VA-TFT, IPS or FFS display devices, and the absolute value of dielectric anisotropy is 10 or greater (for example, 10.5), preferably 12 or greater (for example, 13, 14), preferably 15 or greater (for example, 15.8, 16, 16.4), and is suitable for liquid crystal compositions with high requirements for the absolute value of dielectric anisotropy. In addition, when the compounds of the present invention are applied to liquid crystal compositions, they have good miscibility, good low-temperature storage stability, low rotational viscosity and high VHR (UV), and still have good reliability after ultraviolet treatment.

[0048] In another aspect, the present invention provides a liquid crystal composition comprising at least one liquid crystal compound of the above general formula F.

[0049] In some embodiments of the present invention, it is preferred to adjust the content of the compound of general formula F so that the liquid crystal composition of the present invention has a larger optical anisotropy, a smaller rotational viscosity, a higher VHR (UV) and a longer low-temperature storage time while maintaining an appropriate clearing point, an appropriate absolute value of dielectric anisotropy, and an appropriate VHR (initial).

[0050] In some embodiments of the present invention, the weight percentage of the compound of formula F in the liquid crystal composition is 0.1%-30% (including all values ​​therebetween), for example, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 20%, 22%, 24%, 25%, 26%, 28%, 30% or any range between two of them.

[0051] In some embodiments of the present invention, in order to obtain greater optical anisotropy, smaller rotational viscosity, higher VHR (UV) and longer low-temperature storage time, the liquid crystal composition preferably contains at least two (eg, two or three) compounds of formula F.

[0052] In some embodiments of the present invention, the liquid crystal composition further comprises at least one compound of the general formula N:

[0053]

[0054] in,

[0055] R N1 and R N2 each independently represents a straight or branched chain alkyl group containing 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, One or more non-adjacent -CH2- in a straight-chain or branched alkyl group containing 1 to 12 carbon atoms may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-;

[0056] ring and ring Each independently expresses in One or more -CH2- in the ring may be replaced by -O-, and one or more single bonds in the ring may be replaced by double bonds, wherein One or more -H in the ring may be independently replaced by -F, -Cl or -CN, and one or more -CH= in the ring may be replaced by -N=;

[0057] Z N1 and Z N2 Each independently represents a single bond, -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, -CH2CH2-, -CF2CF2-, -(CH2)4-, -CF2O- or -OCF2-;

[0058] L N1 and LN2 Each independently represents -H, an alkyl radical containing 1 to 3 carbon atoms, or a halogen; and

[0059] n N1 Indicates 0, 1, 2, or 3, n N2 Represents 0 or 1, and 0≤n N1 +n N2 ≤3, where n N1 =2 or 3, the ring Can be the same or different, Z N1 Can be the same or different.

[0060] In some embodiments of the present invention, L N1 and L N2 All represent -H.

[0061] In some embodiments of the present invention, the compound of formula N is selected from the group consisting of:

[0062]

[0063] as well as

[0064] In some embodiments of the present invention, preferably, R N1 and R N2 Each independently represents a straight chain or branched alkyl group containing 1 to 10 carbon atoms, a straight chain or branched alkoxy group containing 1 to 9 carbon atoms, or a straight chain or branched alkenyl group containing 2 to 10 carbon atoms; further preferably, R N1 and R N2 Each independently represents a straight chain or branched chain alkyl group containing 1 to 8 carbon atoms, a straight chain or branched chain alkoxy group containing 1 to 7 carbon atoms, or a straight chain or branched chain alkenyl group containing 2 to 8 carbon atoms.

[0065] In some embodiments of the present invention, preferably, the compound of general formula N is selected from the group consisting of compounds of general formula N-1, compounds of general formula N-2, compounds of general formula N-3, compounds of general formula N-9, compounds of general formula N-12, compounds of general formula N-13, compounds of general formula N-19, compounds of general formula N-21, compounds of general formula N-24, compounds of general formula N-27 and compounds of general formula N-30.

[0066] In some embodiments of the present invention, in order to obtain greater optical anisotropy, larger clearing point, smaller rotational viscosity, appropriate VHR (initial), higher VHR (UV) and longer low-temperature storage time, the compound of general formula N is preferably selected from the group consisting of compounds of general formula N-2, compounds of general formula N-3, compounds of general formula N-9, compounds of general formula N-12 and compounds of general formula N-13.

[0067] In some embodiments of the present invention, in order to obtain greater optical anisotropy, smaller rotational viscosity, higher VHR (UV) and longer low-temperature storage time, the compound of general formula N is preferably selected from the group consisting of compounds of general formula N-1, compounds of general formula N-19, compounds of general formula N-21, compounds of general formula N-24, compounds of general formula N-27 and compounds of general formula N-30.

[0068] In some embodiments of the present invention, the content of the compound of formula N is preferably adjusted so that the liquid crystal composition of the present invention has an appropriate clearing point, an appropriate absolute value of dielectric anisotropy, an appropriate VHR (initial), a larger optical anisotropy, a smaller rotational viscosity, a higher VHR (UV) and a longer low-temperature storage time.

[0069] In some embodiments of the present invention, the weight percentage of the compound of general formula N in the liquid crystal composition is 0.1%-70% (including all values ​​in between), for example, 0.1%, 1%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 37%, 38%, 40%, 42%, 44%, 46%, 48%, 49%, 50%, 52%, 53%, 54%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 64%, 66%, 68%, 70% or any range between two of them.

[0070] In some embodiments of the present invention, the liquid crystal composition further comprises at least one compound of the general formula M:

[0071]

[0072] in,

[0073] R M1 and R M2 each independently represents a straight or branched chain alkyl group containing 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, One or more non-adjacent -CH2- in a straight-chain or branched alkyl group containing 1 to 12 carbon atoms may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-;

[0074] ring ring and ring Each independently expresses in One or more -CH2- in the ring may be replaced by -O-, and one or more single bonds in the ring may be replaced by double bonds, wherein At most one -H in may be replaced by halogen;

[0075] Z M1 and Z M2 Each independently represents a single bond, -CO-O-, -O-CO-, -CH2O-, -OCH2-, -C≡C-, -CH=CH-, -CH2CH2- or -(CH2)4-; and

[0076] n M represents 0, 1 or 2, where n M =2, ring Can be the same or different, Z M2 Can be the same or different.

[0077] In some embodiments of the present invention, preferably, R M1 and R M2 Each independently represents a straight chain or branched alkyl group containing 1 to 10 carbon atoms, a straight chain or branched alkoxy group containing 1 to 9 carbon atoms, or a straight chain or branched alkenyl group containing 2 to 10 carbon atoms; further preferably, R M1 and R M2 Each independently represents a straight chain or branched chain alkyl group containing 1 to 8 carbon atoms, a straight chain or branched chain alkoxy group containing 1 to 7 carbon atoms, or a straight chain or branched chain alkenyl group containing 2 to 8 carbon atoms.

[0078] In some embodiments of the present invention, preferably, R M1 and R M2 Each independently represents a straight chain alkenyl group containing 2 to 8 carbon atoms; further preferably, R M1 and R M2 Each independently represents a straight chain alkenyl group containing 2 to 5 carbon atoms.

[0079] In some embodiments of the present invention, preferably, R M1 and R M2One of them is a straight chain alkenyl group having 2 to 5 carbon atoms, and the other is a straight chain alkyl group having 1 to 5 carbon atoms.

[0080] In some embodiments of the present invention, preferably, R M1 and R M2 Each independently represents a straight chain alkoxy group containing 1 to 8 carbon atoms; further preferably, R M1 and R M2 Each independently represents a straight-chain alkoxy group containing 1 to 5 carbon atoms.

[0081] In some embodiments of the present invention, preferably, R M1 and R M2 One of them is a straight-chain alkoxy group having 1 to 5 carbon atoms, and the other is a straight-chain alkyl group having 1 to 5 carbon atoms.

[0082] In some embodiments of the present invention, when reliability is important, R M1 and R M2 are all alkyl groups; when it is important to reduce the volatility of the compound, R M1 and R M2 are all alkoxy groups; when the viscosity reduction is important, R M1 and R M2 At least one of them is alkenyl.

[0083] As used herein, the term "containing 1-r carbon atoms" (wherein r is an integer greater than 1) may mean containing any integer between 1 and r (including the end values ​​1 and r) carbon atoms, for example, containing 2 carbon atoms, containing (r-1) carbon atoms, or containing r carbon atoms. For example, "containing 1-12 carbon atoms" may mean containing 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms.

[0084] As used herein, the term "integer of y1-y2" can be any integer between the range (including the end values ​​y1 and y2). For example, "integer of 0-12" can be, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12.

[0085] The alkenyl group in the present invention is preferably selected from the group represented by any one of formula (V1) to formula (V9), and is particularly preferably formula (V1), formula (V2), formula (V8) or (V9). The groups represented by formula (V1) to formula (V9) are as follows:

[0086]

[0087] Wherein, * indicates the connection site in the bonded ring structure.

[0088] The alkenyloxy group in the present invention is preferably selected from the group represented by any one of formula (OV1) to formula (OV9), and is particularly preferably the group represented by formula (OV1), formula (OV2), formula (OV8) or formula (OV9). The groups represented by formula (OV1) to formula (OV9) are as follows:

[0089]

[0090] Wherein, * indicates the connection site in the bonded ring structure.

[0091] In some embodiments of the present invention, the compound of formula M is selected from the group consisting of:

[0092]

[0093] as well as

[0094] In some embodiments of the present invention, in order to obtain greater optical anisotropy, appropriate clearing point, smaller rotational viscosity, appropriate VHR (initial), higher VHR (UV) and longer low-temperature storage time, the compound of general formula M is preferably selected from the group consisting of compounds of general formula M-1, compounds of general formula M-4, compounds of general formula M-11 and compounds of general formula M-13.

[0095] In some embodiments of the present invention, the content of the compound of formula M must be appropriately adjusted according to the required properties such as solubility at low temperature, transition temperature, electrical reliability, birefringence, process adaptability, drip marks, screen burn-in, dielectric anisotropy, etc.

[0096] Regarding the content of the compound of general formula M, when it is necessary to keep the viscosity of the liquid crystal composition of the present invention low and the response time short, the lower limit is preferably higher and the upper limit is higher; further, when it is necessary to keep the clearing point of the liquid crystal composition of the present invention high and the temperature stability good, the lower limit is preferably higher and the upper limit is higher; in order to keep the driving voltage low and increase the absolute value of the dielectric anisotropy, the lower limit is preferably lower and the upper limit is lower.

[0097] In some embodiments of the present invention, the content of the compound of formula M is preferably adjusted so that the liquid crystal composition of the present invention has an appropriate clearing point, an appropriate absolute value of dielectric anisotropy, an appropriate VHR (initial), a larger optical anisotropy, a smaller rotational viscosity, a higher VHR (UV) and a longer low-temperature storage time.

[0098] In some embodiments of the present invention, the weight percentage of the compound of formula M in the liquid crystal composition is 0.1%-70% (including all values ​​therebetween), for example, 0.1%, 1%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 35%, 36%, 37%, 38%, 40%, 42%, 44%, 46%, 47%, 48%, 49%, 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66%, 68%, 70% or any range of values ​​therebetween.

[0099] In some embodiments of the present invention, in order to apply the liquid crystal composition of the present invention to a high-transmittance liquid crystal display, the liquid crystal composition of the present invention further comprises at least one compound selected from the group consisting of compounds of formula A-1 and formula A-2:

[0100]

[0101] in,

[0102] R A1 and R A2 each independently represents a straight or branched chain alkyl group containing 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, wherein one or more non-adjacent -CH2- in a straight-chain or branched alkyl group containing 1 to 12 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and wherein a straight-chain or branched alkyl group containing 1 to 12 carbon atoms, One or more -H in can be independently replaced by -F or -Cl;

[0103] ring ring ring and ring Each independently expresses in One or more -CH2- in the ring may be replaced by -O-, and one or more single bonds in the ring may be replaced by double bonds, wherein One or more -H in the ring may be independently replaced by -F, -Cl or -CN, and one or more -CH= in the ring may be replaced by -N=;

[0104] Z A11 , Z A21 and Z A22each independently represents a single bond, -CH2CH2-, -CF2CF2-, -CO-O-, -O-CO-, -O-CO-O-, -CH=CH-, -CF=CF-, -CH2O- or -OCH2-;

[0105] L A11 , L A12 , L A13 , L A21 and L A22 Each independently represents -H, an alkyl group containing 1 to 3 carbon atoms or a halogen;

[0106] X A1 and X A2 Each independently represents halogen, a straight-chain or branched haloalkyl or haloalkoxy group containing 1 to 5 carbon atoms, or a straight-chain or branched haloalkenyl or haloalkenoxy group containing 2 to 5 carbon atoms;

[0107] n A11 represents 0, 1, 2, or 3, where n A11 =2 or 3, the ring Can be the same or different, Z A11 Can be the same or different;

[0108] n A12 represents 1 or 2, where n A12 =2, ring may be the same or different; and

[0109] n A2 represents 0, 1, 2, or 3, where n A2 =2 or 3, the ring Can be the same or different, Z A21 Can be the same or different.

[0110] In some embodiments of the present invention, the compound of formula A-1 is selected from the group consisting of:

[0111]

[0112] as well as

[0113] in,

[0114] R A1 represents a straight or branched alkyl group containing 1 to 8 carbon atoms, wherein one or more non-adjacent -CH2- in a straight or branched alkyl group containing 1 to 8 carbon atoms may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or more -H present in these groups may be independently replaced by -F or -Cl;

[0115] R v and R w Each independently represents -CH2- or -O-;

[0116] L A11 , L A12 , L A11 ', L A12 ', L A14 , L A15 and L A16 Each independently represents -H or -F;

[0117] L A13 and L A13 'Each independently represents -H or -CH3;

[0118] X A1 represents -F, -CF3 or -OCF3; and

[0119] v and w each independently represent 0 or 1.

[0120] In some embodiments of the present invention, the weight percentage of the compound of general formula A-1 in the liquid crystal composition is 0.1%-50% (including all values ​​in between), for example, 0.1%, 1%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50% or any range of values ​​between two of them.

[0121] Regarding the preferred content of the compound of general formula A-1, when the viscosity of the liquid crystal composition of the present invention is kept low and the response speed is fast, it is preferred to make its lower limit value slightly lower and the upper limit value slightly lower; further, when the clearing point of the liquid crystal composition of the present invention is kept high and the temperature stability is good, it is preferred to make its lower limit value slightly lower and the upper limit value slightly lower; in addition, in order to keep the driving voltage low and increase the absolute value of dielectric anisotropy, it is preferred to make its lower limit value slightly higher and the upper limit value slightly higher.

[0122] In some embodiments of the present invention, the compound of formula A-2 is selected from the group consisting of:

[0123] as well as

[0124] in,

[0125] R A2 represents a straight-chain or branched alkyl group containing 1 to 8 carbon atoms, wherein one or more non-adjacent -CH2- in the straight-chain or branched alkyl group containing 1 to 8 carbon atoms may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or more -H present in these groups may be independently replaced by -F or -Cl;

[0126] L A21 , L A22 , L A23 , L A24 and L A25 each independently represents -H or -F; and

[0127] X A2 It represents -F, -CF3, -OCF3 or -CH2CH2CH=CF2.

[0128] In some embodiments of the present invention, the weight percentage of the compound of general formula A-2 in the liquid crystal composition is 0.1%-50% (including all values ​​in between), for example, 0.1%, 1%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50% or any range of values ​​between two of them.

[0129] Regarding the preferred content of the compound of general formula A-2, when the viscosity of the liquid crystal composition of the present invention is kept low and the response speed is fast, it is preferred to make its lower limit value slightly lower and the upper limit value slightly lower; further, when the clearing point of the liquid crystal composition of the present invention is kept high and the temperature stability is good, it is preferred to make its lower limit value slightly lower and the upper limit value slightly lower; in addition, in order to keep the driving voltage low and increase the absolute value of the dielectric anisotropy, it is preferred to make its lower limit value slightly higher and the upper limit value slightly higher.

[0130] In some embodiments of the present invention, the weight percentage of the compound selected from the group consisting of compounds of general formula A-1 and general formula A-2 in the liquid crystal composition is 0.1%-60% (including all values ​​in between), for example, 0.1%, 1%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, 60% or a numerical range between any two of them.

[0131] In some embodiments of the present invention, the liquid crystal composition further comprises at least one polymerizable compound of the general formula RM:

[0132]

[0133] in,

[0134] R1 represents -H, halogen, -CN, -Sp2-P2, a straight or branched chain alkyl group containing 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, A straight or branched alkyl group containing 1 to 12 carbon atoms, One or more non-adjacent -CH2- may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or more -H may be independently replaced by -F or -Cl;

[0135] ring and ring Each independently expresses in One or more -CH2- in the ring may be replaced by -O-, and one or more single bonds in the ring may be replaced by double bonds, wherein One or more -H in the -H can be independently replaced by -F, -Cl, -CN, -Sp3, -P3, a halogenated or unhalogenated straight-chain alkyl group containing 1-12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, a halogenated or unhalogenated straight-chain alkoxy group containing 1-11 carbon atoms, Substitution, and -CH= in one or more rings may be replaced by -N=;

[0136] ring express in One or more -H in the above-mentioned group may be replaced by -F, -Cl, -CN, -Sp3, -P3, a halogenated or unhalogenated straight-chain alkyl group having 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) carbon atoms, a halogenated or unhalogenated straight-chain alkoxy group having 1 to 11 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11) carbon atoms, Substitution, and -CH= in one or more rings may be replaced by -N=;

[0137] P1, P2 and P3 each independently represent a polymerizable group;

[0138] Sp1, Sp2 and Sp3 each independently represent a spacer group or a single bond;

[0139] Z1 and Z2 each independently represent -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CH2O-, -OCH2-, -CH2S-, -SCH2-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -(CH2) d -, -CF2CH2-, -CH2CF2-, -(CF2) d -, -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH-, -CH2CH2-CO-O-, -O-CO-CH2CH2-, -CHR 1 -、-CR 1 R 2 - or a single bond, where R 1 and R 2 Each independently represents a straight or branched alkyl group containing 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12) carbon atoms, and d represents an integer of 1 to 4; X0 represents -O-, -S-, -CO-, -CF2-, -NH- or -NF-;

[0140] a represents 0, 1 or 2, b represents 0 or 1, wherein when a represents 2, the ring can be the same or different, and Z1 can be the same or different.

[0141] In some embodiments of the present invention, the compound of formula RM is selected from the group consisting of:

[0142]

[0143]

[0144] as well as

[0145] in,

[0146] X1-X 10 and X 12 Each independently represents -F, -Cl, -Sp3-P3, a linear alkyl or alkoxy group containing 1 to 5 carbon atoms,

[0147] The polymerizable groups involved in the present invention are groups suitable for polymerization reactions (e.g., free radical or ionic polymerization, addition polymerization or condensation polymerization), or groups suitable for addition or condensation on the polymer backbone. For chain polymerization, polymerizable groups containing -CH=CH- or -C≡C- are particularly preferred, and for ring-opening polymerization, for example, oxetane or epoxy groups are particularly preferred.

[0148] In some embodiments of the present invention, the polymerizable groups P1, P2 and P3 each independently represent or -SH; Preferably, the polymerizable groups P1, P2 and P3 each independently represent or -SH; Further preferably, the polymerizable groups P1, P2 and P3 each independently represent

[0149] As used herein, the term "spacer group" is known to those skilled in the art and is described in the literature (e.g., Pure Appl. Chem. 2001, 73 (5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368). As used herein, the term "spacer group" refers to a flexible group that connects the mesogenic group and the polymerizable group in a polymerizable compound. Typical spacer groups are, for example, -(CH2)p1-, -(CH2CH2O)q1-CH2CH2-, -(CH2CH2S)q1-CH2CH2-, -(CH2CH2NH)q1-CH2CH2-, -CR 0 R 00 -(CH2) p1 -or-(SiR 0 R 00 -O)p1-, wherein p1 represents an integer from 1 to 12, q1 represents an integer from 1 to 3, and R 0 and R00 Each independently represents -H, a straight or branched alkyl group containing 1 to 12 carbon atoms, or a cyclic alkyl group containing 3 to 12 carbon atoms. Particularly preferred spacer groups are -(CH2)p1-, -(CH2)p1-O-, -(CH2)p1-O-CO-, -(CH2)p1-CO-O-, -(CH2)p1-O-CO-O- or -CR 0 R 00 -(CH2) p1 -.

[0150] In some embodiments of the present invention, the weight percentage of the polymerizable compound of the general formula RM in the liquid crystal composition is 0.001%-5% (including all values ​​therebetween), for example, 0.001%, 0.002%, 0.004%, 0.005%, 0.006%, 0.008%, 0.01%, 0.02%, 0.04%, 0.06%, 0.08%, 0.1%, 0.2 %, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.3%, 0.32%, 0.33%, 0.34%, 0.35%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.6%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% or any range between two of them.

[0151] In some embodiments of the present invention, the liquid crystal composition further comprises at least one additive.

[0152] In addition to the above compounds, the liquid crystal composition of the present invention may also contain conventional nematic liquid crystals, smectic liquid crystals, cholesteric liquid crystals, dopants, antioxidants, ultraviolet absorbers, infrared absorbers, polymerizable monomers or light stabilizers.

[0153] Possible dopants which are preferably added to the liquid crystal composition according to the invention are shown below:

[0154]

[0155] as well as

[0156] In some embodiments of the present invention, the weight percentage of the dopant in the liquid crystal composition is 0%-5%; preferably, the weight percentage of the dopant in the liquid crystal composition is 0.01%-1%.

[0157] In addition, the antioxidant, light stabilizer, ultraviolet absorber and other additives used in the liquid crystal composition of the present invention are preferably the following:

[0158]

[0159]

[0160]

[0161] Here, n represents a positive integer from 1 to 12.

[0162] Preferably, the antioxidant is selected from the compounds shown below:

[0163]

[0164] In some embodiments of the present invention, the additive accounts for 0%-5% of the total weight of the liquid crystal composition; preferably, the additive accounts for 0.01%-1% of the total weight of the liquid crystal composition.

[0165] Even in the absence of a polymerization initiator, the liquid crystal composition containing a polymerizable compound of the present invention can be polymerized, but in order to promote polymerization, a polymerization initiator may be further contained therein. Examples of the polymerization initiator include benzoin ethers, benzophenones, acetophenones, benzyl ketals, acylphosphine oxides, and the like.

[0166] For the polymerization method of the polymerizable compound, since it is expected that the polymerization proceeds quickly, a method of polymerization by irradiation with active energy lines such as ultraviolet rays or electron beams is preferred. When using ultraviolet rays, a polarized light source can be used, or a non-polarized light source can be used. In addition, when the liquid crystal composition is polymerized in a state where it is clamped between two substrates, at least the substrate on the irradiated side must have appropriate transparency relative to the active energy line. In addition, a mask can be used during light irradiation to polymerize only a specific part, and then, by changing conditions such as the electric field, magnetic field or temperature, the orientation state of the unpolymerized part is changed, and further irradiation with active energy lines is performed for polymerization. In particular, when ultraviolet exposure is performed, it is preferred to perform ultraviolet exposure while applying a voltage to the liquid crystal composition.

[0167] The temperature during irradiation with active energy rays such as ultraviolet rays or electron beams is preferably within a temperature range that maintains the liquid crystal state of the liquid crystal composition of the present invention. Polymerization is preferably carried out at a temperature close to room temperature (i.e., 15-35°C). As for the lamp that generates ultraviolet rays, metal halide lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, etc. can be used. In addition, as for the wavelength of the irradiated ultraviolet rays, it is preferred to irradiate ultraviolet rays with a wavelength outside the absorption wavelength region of the liquid crystal composition, and it is preferred to use ultraviolet rays that are blocked as needed. The intensity of the irradiated ultraviolet rays is preferably 0.1mW / cm2 -50mW / cm 2 When irradiating ultraviolet rays, the intensity can be changed, and the time of irradiating ultraviolet rays can be appropriately selected according to the intensity of the irradiated ultraviolet rays, preferably 10s-600s.

[0168] In yet another aspect, the present invention further provides a liquid crystal display device, comprising the liquid crystal composition.

[0169] In some embodiments of the present invention, the liquid crystal composition is particularly suitable for use in VA, IPS or FFS type display devices.

[0170] Beneficial effects: Compared with the prior art, the liquid crystal compound of the present invention has a larger clearing point, a larger optical anisotropy, and a comparable or larger absolute value of dielectric anisotropy while maintaining an appropriate rotational viscosity. The liquid crystal composition containing the above liquid crystal compound of the present invention has a larger optical anisotropy, a smaller rotational viscosity, a higher VHR (UV), and a longer low-temperature storage time while maintaining an appropriate clearing point, an appropriate absolute value of dielectric anisotropy, and an appropriate VHR (initial), so that the liquid crystal display device containing it has a better contrast, a faster response speed, a higher reliability, and a better low-temperature storage stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0171] Figure 1 It is the mass spectrum of compound F-2-4.

[0172] Figure 2 It is the DSC cooling spectrum of compound F-2-4.

[0173] Figure 3 It is the DSC temperature rise spectrum of compound F-2-4.

[0174] Figure 4 It is the mass spectrum of compound F-1-4.

[0175] Figure 5 It is the DSC cooling spectrum of compound F-1-4.

[0176] Figure 6 It is the DSC temperature rise spectrum of compound F-1-4. DETAILED DESCRIPTION

[0177] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0178] In the present invention, unless otherwise specified, the contents are expressed in percentage by weight.

[0179] For ease of expression, in the following examples, the group structure of each compound is represented by the code listed in Table 2:

[0180] Table 2. Group structure codes of compounds

[0181]

[0182]

[0183] Take the following compound as an example:

[0184]

[0185] If the structural formula is represented by the codes listed in Table 2, it can be expressed as: nCCGF, where n in the code represents the number of C atoms in the left-hand alkyl group, for example, n is "3", which means that the alkyl group is -C3H7; C in the code represents 1,4-cyclohexylene, G represents 2-fluoro-1,4-phenylene, and F represents a fluorine substituent.

[0186] The abbreviated codes for the test items in the following embodiments are as follows:

[0187] Cp clearing point (nematic-isotropic phase transition temperature, °C)

[0188] Δn optical anisotropy (589nm, 20℃)

[0189] Δε Dielectric anisotropy (1KHz, 20℃)

[0190] VHR(initial) Initial voltage holding ratio (%)

[0191] VHR(UV) Voltage holding ratio after ultraviolet light (UV) irradiation (%)

[0192] t -30℃ Low temperature storage time (days, -30℃)

[0193] γ1 Rotational viscosity (mPa·s, 20℃)

[0194] in,

[0195] Cp: ​​obtained by melting point test.

[0196] Δn: measured using an Abbe refractometer under a sodium lamp (589 nm) at 20°C.

[0197] Δε: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: 20°C, 1KHz, VA type test box with a box thickness of 6μm.

[0198] VHR(initial): initial voltage holding rate, tested using TOY06254 liquid crystal property evaluation system; test temperature is 60°C, test voltage is 5V, test frequency is 6Hz, and the cell thickness is 9μm TN type test cell.

[0199] VHR (UV) is measured using the TOY06254 liquid crystal property evaluation system; the wavelength used is 365nm and the energy is 6000mJ / cm 2 The test was conducted after the liquid crystal was irradiated with UV light, the test temperature was 60°C, the test voltage was 5V, the test frequency was 6Hz, and the cell thickness was 9μm in a TN type test cell.

[0200] t -30℃ : The nematic liquid crystal medium is placed in a glass bottle and stored at -30°C, and the time is recorded when crystal precipitation is observed.

[0201] γ1: obtained by testing using LCM-2 liquid crystal property evaluation system; test conditions: 20°C, 160-240V, test box thickness 20μm.

[0202] The liquid crystal compound of the general formula F of the present invention can be prepared by conventional organic synthesis methods, wherein the method of introducing the target terminal group, ring structure and connecting group into the starting material is described in the following documents: Organic Synthesis (John Wiley & Sons Inc.), Organic Reactions (John Wiley & Sons Inc.) and Comprehensive Organic Synthesis (Pergamon Press), etc.

[0203] Synthesis of the linking group Z in the liquid crystal compound of the general formula F F1 To Z F3 The method can refer to the following process, where MSG 1 or MSG 2 It is a monovalent organic group having at least one ring. The multiple MSG used in the following process 1 (or MSG 2 ) can be the same or different.

[0204] (1) Synthesis of single bonds

[0205]

[0206] The arylboronic acid 1 is reacted with the compound 2 synthesized by a known method in an aqueous sodium carbonate solution in the presence of a catalyst (such as tetrakis(triphenylphosphine)palladium (Pd(PPh3)4)) to obtain the single-bond compound IA. The single-bond compound IA can also be prepared by reacting the compound 3 synthesized by a known method with n-butyllithium (n-BuLi), then with zinc chloride, and then reacting with the compound 2 in the presence of a catalyst (such as dichlorobis(triphenylphosphine)palladium (PdCl2(PPh3)2)).

[0207] (2) Synthesis of -CO-O- and -O-CO-

[0208]

[0209] Compound 3 is reacted with n-butyl lithium and then with carbon dioxide to obtain carboxylic acid 4. Compound 4 and compound 5 synthesized by a known method are dehydrated in the presence of 1,3-dicyclohexylcarbodiimide (DCC) and 4-dimethylaminopyridine (DMAP) to synthesize compound IB having -CO-O-. A compound having -O-CO- can also be synthesized by this method.

[0210] (3) Synthesis of -CF2O- and -OCF2-

[0211]

[0212] Referring to M. Kuroboshi et al., Chem. Lett., 1992, 827, compound 6 is obtained by treating compound IB with a sulfiding agent (such as Lawesson's reagent), and then compound 6 is fluorinated with hydrogen fluoride-pyridine (HF-Py) and N-bromosuccinimide (NBS) to synthesize compound IC having -CF2O-. Also referring to WH Bunnelle et al., Journal of Organic Chemistry (J. Org. Chem), 1990, 55, 768., compound IC having -CF2O- is prepared by fluorinating compound 6 with (diethylamino) sulfur trifluoride (DAST). Compounds having -OCF2- can also be synthesized by these methods.

[0213] (4) Synthesis of -CH=CH-

[0214]

[0215] Compound 3 is reacted with n-butyl lithium and then with formamide (such as N,N-dimethylformamide (DMF)) to obtain compound 7. Potassium tert-butoxide (t-BuOK) is reacted with phosphonium salt 8 synthesized by known methods to generate phosphorus ylid and compound 7 to obtain compound ID. Due to the reaction conditions, the above method generates cis isomers. It should be understood that the cis isomer can be converted to the trans isomer by known methods as needed.

[0216] (5) Synthesis of -CH2CH2-

[0217]

[0218] Compound IE can be prepared by subjecting Compound ID to a hydrogenation reaction using a catalyst such as palladium on carbon (Pd / C).

[0219] (6) Synthesis of -CH2O- or -OCH2-

[0220]

[0221] Compound 7 is reduced using sodium borohydride (NaBH4) to obtain compound 9. Compound 9 is then halogenated with hydrobromic acid to obtain compound 10, or the hydroxyl group of compound 9 is protected with p-toluenesulfonic acid (TsOH) to obtain compound 11. Compound 10 or compound 11 is then reacted with compound 5 in the presence of potassium carbonate to obtain compound IF. Compounds having -OCH2- can also be synthesized by these methods.

[0222] (7) Synthesis of -CH=CF2

[0223]

[0224] Compound IG can be prepared by removing the hydrofluoric acid on the terminal chain of compound 11 using a tetrahydrofuran solution of lithium diisopropylamide (LDA).

[0225] Regarding ring structures such as 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, and 2,3,5,6-tetrafluoro-1,4-phenylene, starting materials are commercially available or their synthesis methods are well known in the art.

[0226] Preferred synthetic methods for representative compounds are illustrated below.

[0227] Synthesis Example 1

[0228] The synthetic route of compound F-2-4 is as follows:

[0229]

[0230] Step 1. Preparation of the compound of formula B-3

[0231] In a 2L reaction bottle, add 99g of the compound of formula B-1 ((4-butoxy-2,3-difluorophenyl)boric acid), 100g of the compound of formula B-2 (2-bromo-6-fluorophenol) and 110g of sodium carbonate, and fully dissolve them in 1.2L of a mixed solvent consisting of toluene, ethanol and water (the volume ratio of toluene, ethanol and water is 2:1:1). Under the protection of nitrogen atmosphere, add 1.8g of Pd(PPh3)4 and reflux at 100°C for 6h. The reaction solution was cooled to room temperature, 300 mL of water was added for liquid separation, the aqueous phase was extracted with 20 mL of toluene, the organic phases were combined, the organic phases were washed with saturated NaCl aqueous solution to pH = 7, dried over anhydrous Na2SO4, concentrated, and recrystallized with a mixed solvent consisting of petroleum ether and toluene (the volume ratio of petroleum ether to toluene is 24:1) to obtain 109.5 g of compound of formula B-3 (4'-butoxy-2',3',3-trifluoro-[1,1'-biphenyl]-2-ol) as a white solid (yield: 85%).

[0232] Step 2. Preparation of the compound of formula B-4

[0233] 110 g of the compound of formula B-3 and 72 g of potassium carbonate were added to a 2 L reaction bottle, fully dissolved with 700 mL of N, N-dimethylformamide, and reacted at 120 ° C for 9 h. The reaction mixture was cooled to room temperature, 3.5 L of water was added, stirred, and filtered to obtain a crude product, which was slurried with ethanol, filtered, and dried over anhydrous Na2SO4 to obtain 88.5 g of the compound of formula B-4 (3-butoxy-4,6-difluorodibenzo[b,d]furan) as a gray solid (yield: 86.3%).

[0234] Step 3. Preparation of the compound of formula B-5

[0235] Add 38g of diisopropylamine to a 2L reaction bottle, fully dissolve it with 500mL of tetrahydrofuran, and add 150mL of n-butyl lithium under the protection of nitrogen atmosphere, and react for 3h at -20℃. Add 90g of the compound of formula B-4, and react for 3h at -78℃. Add 70g of triisopropyl borate, and react for 3h at 78℃. Adjust pH to 2-3 with dilute hydrochloric acid, separate the liquids, extract the aqueous phase with ethyl acetate, combine the organic phases, wash the organic phase with saturated NaCl aqueous solution to pH = 7, dry over anhydrous Na2SO4, concentrate, slurry with dichloromethane, filter with suction, and dry the filter cake to obtain 73g of the compound of formula B-5 ((4,6-difluoro-7-butoxydibenzo[b,d]furan-3-yl)boric acid) as a white solid (yield: 70%).

[0236] Step 4. Preparation of the compound of formula B-6

[0237] 70 g of the compound of formula B-5 was added to a 2L reaction bottle, fully dissolved with 700 mL of tetrahydrofuran, 68 g of 30% hydrogen peroxide was added at a temperature of 10°C, the temperature was controlled at 10°C for 9 hours, quenched with 500 mL of 5% sodium thiosulfate solution, separated, the aqueous phase was extracted with ethyl acetate, the organic phases were combined, the organic phases were washed with saturated NaCl aqueous solution to pH = 7, dried over anhydrous Na2SO4, concentrated, slurried with 25 mL of dichloromethane, filtered, and the filter cake was dried to obtain 55.6 g of the compound of formula B-6 (4,6-difluoro-7-butoxydibenzo[b,d]furan-3-ol) as a white solid (yield: 90%).

[0238] Step 5. Preparation of the compound of formula B-7

[0239] 70 g of the compound of formula B-6 was added to a 2L reaction bottle, fully dissolved with 700 mL of tetrahydrofuran, 68 g of trifluoroethanol was added at a temperature of 10°C, and the temperature was controlled at 10°C for 9 hours. The aqueous phase was extracted with ethyl acetate, the organic phases were combined, and the organic phases were washed with a saturated aqueous NaCl solution to pH = 7, dried over anhydrous Na2SO4, concentrated, slurried with 25 mL of dichloromethane, filtered, and the filter cake was dried to obtain 53.8 g of the compound of formula B-7 (4,6-difluoro-3-butoxy-7-(2,2,2-trifluoroethoxy)dibenzo[b,d]furan) as a white solid (yield: 60%).

[0240] Step 6. Preparation of compound of formula F-2-4

[0241] 40 g of the compound of formula B-7 was added to a 2L reaction bottle, fully dissolved with 700 mL of tetrahydrofuran, 40 g of 30% sodium hydroxide solution was added at a temperature of 10°C, the reaction was reacted for 8 h, and the reaction was quenched with 500 mL of 5% sodium thiosulfate. The liquids were separated, the aqueous phase was extracted with ethyl acetate, the organic phases were combined, and the organic phases were washed with saturated NaCl aqueous solution to pH = 7, dried over anhydrous Na2SO4, concentrated, slurried with 25 mL of dichloromethane, filtered, and the filter cake was dried to obtain 28.4 g of the compound of formula F-2-4 (3-((2,2-difluorovinyl)oxy)-4,6-difluoro-7-butoxydibenzo[b,d]furan) as a white solid (yield: 75%).

[0242] The mass spectrum of the compound of formula F-2-4 is as follows Figure 1 shown.

[0243] The DSC cooling spectrum of the compound of formula F-2-4 is as follows Figure 2 shown.

[0244] The DSC temperature rise pattern of the compound of formula F-2-4 is as follows Figure 3 shown.

[0245] Synthesis Example 2

[0246] The synthetic route of compound F-1-4 is as follows:

[0247]

[0248] The synthesis method of the compound of formula B-3 is the same as that of Synthesis Example 1.

[0249] Step 1. Preparation of the compound of formula B-8

[0250] In a 1L reaction bottle, add 120g of the compound of formula B-3, 120g of dimethylaminothiocarbonyl chloride and 90g of triethylamine, fully dissolve with 440mL of isododecane, and under the protection of nitrogen atmosphere, control the temperature at 165°C to reflux for 18h, cool to 25°C, filter, recrystallize with ethanol, filter, and dry the filter cake to obtain 78.9g of the compound of formula B-8 (3-butoxy-4,6-difluorodibenzo[b,d]thiophene) as a brown solid (yield: 66.667%).

[0251] Step 2. Preparation of the compound of formula B-9

[0252] Add 38g of diisopropylamine to a 2L reaction bottle, fully dissolve it with 500mL of tetrahydrofuran, and add 150mL of n-butyl lithium under the protection of nitrogen atmosphere, and react for 3h at -20℃. Add 80g of the compound of formula B-8, and react for 3h at -78℃. Add 70g of triisopropyl borate, and react for 3h at 78℃. Adjust pH to 2-3 with dilute hydrochloric acid, separate the liquids, extract the aqueous phase with ethyl acetate, combine the organic phases, wash the organic phase with saturated NaCl aqueous solution to pH = 7, dry over anhydrous Na2SO4, concentrate, slurry with dichloromethane, filter with suction, and dry the filter cake to obtain 69g of the compound of formula B-9 (((4,6-difluoro-7-butoxydibenzo[b,d]thiophene-3-yl)boric acid) as a white solid (yield: 75%).

[0253] Step 3. Preparation of the compound of formula B-10

[0254] 70 g of the compound of formula B-9 was added to a 2L reaction bottle, fully dissolved with 700 mL of tetrahydrofuran, 80 g of 30% hydrogen peroxide was added at a temperature of 10°C, the temperature was controlled at 10°C for 9 hours, quenched with 500 mL of 5% sodium thiosulfate solution, separated, the aqueous phase was extracted with ethyl acetate, the organic phases were combined, the organic phases were washed with a saturated NaCl aqueous solution to pH = 7, dried over anhydrous Na2SO4, concentrated, slurried with 25 mL of dichloromethane, filtered, and the filter cake was dried to obtain 41.3 g of the compound of formula B-10 (4,6-difluoro-7-butoxydibenzo[b,d]thiophene-3-ol) as a white solid (yield: 64.3%).

[0255] Step 4. Preparation of the compound of formula B-11

[0256] 70 g of the compound of formula B-10 was added to a 2L reaction bottle, fully dissolved with 700 mL of tetrahydrofuran, 68 g of trifluoroethanol was added at a temperature of 10°C, and the temperature was controlled at 10°C for 9 hours. The aqueous phase was extracted with ethyl acetate, the organic phases were combined, and the organic phases were washed with a saturated aqueous NaCl solution to pH = 7, dried over anhydrous Na2SO4, concentrated, slurried with 25 mL of dichloromethane, filtered, and the filter cake was dried to obtain 56.7 g of the compound of formula B-11 (4,6-difluoro-3-butoxy-7-(2,2,2-trifluoroethoxy)dibenzo[b,d]furan) as a white solid (yield: 64%).

[0257] Step 5. Preparation of the compound of formula F-1-4

[0258] 40 g of the compound of formula B-11 was added to a 2L reaction bottle, fully dissolved with 700 mL of tetrahydrofuran, 40 g of 30% sodium hydroxide solution was added at a temperature of 10°C, the temperature was controlled at 10°C for 8 h, the reaction was quenched with 500 mL of 5% sodium thiosulfate, the liquids were separated, the aqueous phase was extracted with ethyl acetate, the organic phases were combined, the organic phases were washed with saturated NaCl aqueous solution to pH = 7, dried over anhydrous Na2SO4, concentrated, slurried with 25 mL of dichloromethane, filtered, and the filter cake was dried to obtain 30.4 g of a white solid compound of formula F-1-4 (3-((2,2-difluorovinyl)oxy)-4,6-difluoro-7-butoxydibenzo[b,d]furan) (yield: 80%).

[0259] The mass spectrum of the compound of formula F-1-4 is as follows Figure 4 shown.

[0260] The DSC cooling spectrum of the compound of formula F-1-4 is as follows Figure 5 shown.

[0261] The DSC temperature rise pattern of the compound of formula F-1-4 is as follows Figure 6 shown.

[0262] The compound of the general formula F prepared in the above example and the compound DB-1 known in the prior art were mixed. and DB-2 The mixture was mixed with the mother liquid crystal in a weight percentage ratio of 10%:90%. The performance parameter values ​​of the compound to be tested were calculated using the extrapolation method, where the extrapolated values ​​of Cp, Δn and Δε = ((measured value of the mixture) - 0.9 × (measured value of the mother liquid crystal)) / 0.1, and the extrapolated value of γ1 = 10 10(lgA-0.9lgB) , where A is the γ1 of the mixture and B is the γ1 of the parent liquid crystal. According to this method, the values ​​of performance parameters such as clearing point Cp, optical anisotropy Δn, dielectric anisotropy Δε and rotational viscosity γ1 are derived.

[0263] Table 3: Composition of the parent liquid crystal

[0264]

[0265]

[0266] The extrapolated results of the liquid crystal performance parameters of the above compounds are shown in Table 4 below:

[0267] Table 2

[0268] Compound General code Cp Δn <![CDATA[γ1]]> Δε 1OB(O)O4 DB-1 26 0.1557 194 -11 C(5)OB(O)O4 DB-2 50 0.1594 250 -12 4OB(O)OV2F F-2-4 84 0.1603 190 -10.5 2OB(S)OV2F F-1-2 76 0.1613 200 -15.8 3L1OB(O)OV2F F-9-3 120 0.1654 301 -12 4OB(S)OV2F F-1-4 82 0.1619 201 -16.4

[0269] From the comparison of the performance parameter test results of compounds DB-1, DB-2 and the compound of formula F of the present invention in Table 4, it can be seen that the compound of general formula F of the present invention has a larger clearing point, a larger optical anisotropy and a comparable or larger absolute value of dielectric anisotropy while maintaining an appropriate rotational viscosity.

[0270] Each component used in the following examples can be synthesized by a known method or obtained through commercial channels. These synthesis techniques are conventional, and each liquid crystal compound obtained meets the standards of electronic compounds after testing.

[0271] In the present invention, unless otherwise specified, the contents are expressed in percentage by weight.

[0272] Liquid crystal compositions are prepared according to the ratios of the liquid crystal compositions specified in the following examples. The preparation of the liquid crystal compositions is carried out according to conventional methods in the art, such as mixing in proportion by heating, ultrasonic waves, suspension, etc.

[0273] Application Comparative Example 1

[0274] The liquid crystal composition of Application Comparative Example 1 was prepared according to the compounds and their weight percentages listed in Table 5, and filled between two substrates of a liquid crystal display for performance testing.

[0275] Table 5. Liquid crystal composition formula and performance parameter test results

[0276]

[0277]

[0278] Application Example 1

[0279] The liquid crystal composition of Application Example 1 was prepared according to the compounds and their weight percentages listed in Table 6, and filled between two substrates of a liquid crystal display for performance testing.

[0280] Table 6. Liquid crystal composition formula and performance parameter test results

[0281]

[0282] From the comparison between Application Comparative Example 1 and Application Example 1, it can be seen that the liquid crystal composition of the present invention has a smaller rotational viscosity, a higher VHR (UV) and a longer low-temperature storage time while maintaining an appropriate clearing point, an appropriate optical anisotropy, an appropriate dielectric anisotropy and an appropriate VHR (initial).

[0283] Application Comparative Example 2

[0284] The liquid crystal composition of Application Comparative Example 2 was prepared according to the compounds and their weight percentages listed in Table 7, and filled between two substrates of a liquid crystal display for performance testing.

[0285] Table 7. Liquid crystal composition formula and performance parameter test results

[0286]

[0287]

[0288] Application Example 2

[0289] The liquid crystal composition of Application Example 2 was prepared according to the compounds and their weight percentages listed in Table 8, and filled between two substrates of a liquid crystal display for performance testing.

[0290] Table 8. Liquid crystal composition formula and performance parameter test results

[0291]

[0292] From the comparison between Application Comparative Example 2 and Application Example 2, it can be seen that the liquid crystal composition of the present invention has a larger optical anisotropy, a smaller rotational viscosity, a higher VHR (UV) and a longer low-temperature storage time while maintaining an appropriate clearing point, an appropriate absolute value of dielectric anisotropy and an appropriate VHR (initial).

[0293] Application Comparative Example 3

[0294] The liquid crystal composition of Application Comparative Example 3 was prepared according to the compounds and their weight percentages listed in Table 9, and filled between two substrates of a liquid crystal display for performance testing.

[0295] Table 9. Liquid crystal composition formula and performance parameter test results

[0296]

[0297] Application Example 3

[0298] The liquid crystal composition of Application Example 3 was prepared according to the compounds and their weight percentages listed in Table 10, and filled between two substrates of a liquid crystal display for performance testing.

[0299] Table 10. Liquid crystal composition formulation and performance parameter test results

[0300]

[0301]

[0302] From the comparison between Comparative Example 3 and Application Example 3, it can be seen that the liquid crystal composition of the present invention has a smaller rotational viscosity, a higher VHR (UV) and a longer low-temperature storage time while maintaining an appropriate clearing point, an appropriate optical anisotropy, an appropriate absolute value of dielectric anisotropy and an appropriate VHR (initial).

[0303] Application Example 4

[0304] Liquid crystal compositions were prepared according to the compounds and their weight percentages listed in Table 11, and 0.3% by weight of It was added to the liquid crystal composition shown in Table 11 as Application Example 4, and filled between two substrates of a liquid crystal display for performance testing.

[0305] Table 11. Liquid crystal composition formula and performance parameter test results

[0306]

[0307] Application Example 5

[0308] Adding 0.3% of the polymerizable compound of RM-1-1 into the liquid crystal composition in Example 1 can achieve polymerization with a faster angular velocity and form a smaller pre-tilt angle.

[0309]

[0310] Application Example 6

[0311] Adding 0.3% of the polymerizable compound of RM-2-1 into the liquid crystal composition in Example 2 can achieve polymerization with a faster angular velocity and form a smaller pre-tilt angle.

[0312]

[0313] Application Example 7

[0314] The liquid crystal composition of Application Example 7 was prepared according to the compounds and their weight percentages listed in Table 12, and filled between two substrates of a liquid crystal display for performance testing.

[0315] Table 12. Liquid crystal composition formulation and performance parameter test results

[0316]

[0317] Application Example 8

[0318] The liquid crystal composition of Application Example 8 was prepared according to the compounds and their weight percentages listed in Table 13, and filled between two substrates of a liquid crystal display for performance testing.

[0319] Table 13. Liquid crystal composition formula and performance parameter test results

[0320]

[0321]

[0322] Application Example 9

[0323] Liquid crystal compositions were prepared according to the compounds and their weight percentages listed in Table 14, and 0.3% by weight of It was added to the liquid crystal composition shown in Table 14 as Application Example 9, and filled between two substrates of a liquid crystal display for performance testing.

[0324] Table 14. Liquid crystal composition formulation and performance parameter test results

[0325]

[0326] Application Example 10

[0327] Liquid crystal compositions were prepared according to the compounds and their weight percentages listed in Table 15, and 0.3% by weight of It was added to the liquid crystal composition shown in Table 15 as Application Example 10, and filled between two substrates of a liquid crystal display for performance testing.

[0328] Table 15. Liquid crystal composition formulation and performance parameter test results

[0329]

[0330] Application Example 11

[0331] Liquid crystal compositions were prepared according to the compounds and their weight percentages listed in Table 16, and 0.3% by weight of It was added to the liquid crystal composition shown in Table 16 as Application Example 11, and filled between two substrates of a liquid crystal display for performance testing.

[0332] Table 16. Liquid crystal composition formulation and performance parameter test results

[0333]

[0334] Application Example 12

[0335] Liquid crystal compositions were prepared according to the compounds and their weight percentages listed in Table 17, and 0.3% by weight of It was added to the liquid crystal composition shown in Table 17 as Application Example 12, and filled between two substrates of a liquid crystal display for performance testing.

[0336] Table 17. Liquid crystal composition formulation and performance parameter test results

[0337]

[0338] Application Example 13

[0339] Liquid crystal compositions were prepared according to the compounds and their weight percentages listed in Table 18, and 0.3% by weight of It was added to the liquid crystal composition shown in Table 18 as Application Example 13, and filled between two substrates of a liquid crystal display for performance testing.

[0340] Table 18. Liquid crystal composition formulation and performance parameter test results

[0341]

[0342]

[0343] In summary, the liquid crystal compound of the general formula F provided by the present invention has a larger clearing point, a larger optical anisotropy and a comparable or larger absolute value of dielectric anisotropy while maintaining an appropriate rotational viscosity; the liquid crystal composition of the present invention has a larger optical anisotropy, a smaller rotational viscosity, a higher VHR (UV) and a longer low-temperature storage time while maintaining an appropriate clearing point, an appropriate absolute value of dielectric anisotropy and an appropriate VHR (initial), so that the liquid crystal display device containing it has better contrast, faster response speed, higher reliability and better low-temperature storage stability.

[0344] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A liquid crystal compound of general formula F: in, R F1 represents -H, halogen, a straight or branched alkyl group containing 1 to 12 carbon atoms, wherein one or more non-adjacent -CH2- in the straight-chain or branched alkyl group containing 1 to 12 carbon atoms can be independently replaced by -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or more -H in the straight-chain or branched alkyl group containing 1 to 12 carbon atoms can be independently replaced by -F or -Cl; ring and ring Each independently expresses in One or more -CH2- in the ring can be replaced by -O-, and one or more single bonds in the ring can be replaced by double bonds, wherein One or more -H in the ring can be independently replaced by -CN, -F or -Cl, and one or more -CH= in the ring can be replaced by -N=; X F represents -O-, -S-, or -CO-; L F1 and L F2 Each independently represents -H, -F, -Cl, -CF3 or -OCF3; Z F1 and Z F2 Each independently represents a single bond, -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, -CH2CH2-, -CF2CF2-, -(CH2)4-, -CF2O- or -OCF2-; n F1 Represents 0, 1, or 2, n F2 represents 0, where n F1 When it indicates 2, the ring the same or different; and n F3 Represents an integer from 0 to 4.

2. The liquid crystal compound according to claim 1, characterized in that The compound of formula F is selected from the group consisting of the following compounds: as well as in, X F1 and X F2 Each independently represents -CH2- or -O-.

3. The liquid crystal compound according to claim 1, characterized in that X F Means -S-.

4. A liquid crystal composition comprising at least one liquid crystal compound of the general formula F according to any one of claims 1 to 3.

5. The liquid crystal composition according to claim 4, characterized in that: The liquid crystal composition further comprises at least one compound of the general formula N: in, R N1 and R N2 Each independently represents a straight or branched alkyl group containing 1 to 12 carbon atoms, wherein one or more non-adjacent -CH2- in the straight-chain or branched alkyl group containing 1 to 12 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-; ring and ring Each independently expresses in One or more -CH2- in the ring can be replaced by -O-, and one or more single bonds in the ring can be replaced by double bonds, wherein One or more -H in the ring can be independently replaced by -F, -Cl or -CN, and one or more -CH= in the ring can be replaced by -N=; Z N1 and Z N2 Each independently represents a single bond, -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, -CH2CH2-, -CF2CF2-, -(CH2)4-, -CF2O- or -OCF2-; L N1 and L N2 Each independently represents -H, an alkyl radical containing 1 to 3 carbon atoms, or a halogen; and n N1 Represents 0, 1, 2, or 3, n N2 Represents 0 or 1, and 0≤n N1 +n N2 ≤3, where n N1 =2 or 3, the ring Same or different, Z N1 Same or different.

6. The liquid crystal composition according to claim 5, characterized in that: The compound of formula N is selected from the group consisting of the following compounds: as well as 7. The liquid crystal composition according to claim 5, characterized in that: The liquid crystal composition further comprises at least one compound of the general formula M: in, R M1 and R M2 Each independently represents a straight or branched alkyl group containing 1 to 12 carbon atoms, wherein one or more non-adjacent -CH2- in the straight-chain or branched alkyl group containing 1 to 12 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-; ring ring and ring Each independently expresses in One or more -CH2- in the ring can be replaced by -O-, and one or more single bonds in the ring can be replaced by double bonds, wherein At most one -H in can be replaced by a halogen; Z M1 and Z M2 Each independently represents a single bond, -CO-O-, -O-CO-, -CH2O-, -OCH2-, -C≡C-, -CH=CH-, -CH2CH2- or -(CH2)4-; and n M represents 0, 1, or 2, where n M =2, ring Same or different, Z M2 Same or different.

8. The liquid crystal composition according to claim 7, characterized in that: The compound of formula M is selected from the group consisting of the following compounds: as well as 9. The liquid crystal composition according to claim 7, characterized in that: The liquid crystal composition further comprises at least one polymerizable compound of the general formula RM: in, R1 represents -H, halogen, -CN, -Sp2-P2, a straight or branched alkyl group containing 1 to 12 carbon atoms, wherein the straight or branched alkyl group containing 1 to 12 carbon atoms, One or more non-adjacent -CH2- can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or more -H can be independently replaced by -F or -Cl; ring and ring Each independently expresses in One or more -CH2- in the ring can be replaced by -O-, and one or more single bonds in the ring can be replaced by double bonds, wherein One or more -H in the -H can be independently replaced by -F, -Cl, -CN, -Sp3-P3, a halogenated or unhalogenated straight-chain alkyl group containing 1 to 12 carbon atoms, a halogenated or unhalogenated straight-chain alkoxy group containing 1 to 11 carbon atoms, Substitution, and one or more ring -CH= can be replaced by -N=; ring express in One or more -H in the -H can be independently replaced by -F, -Cl, -CN, -Sp3-P3, a halogenated or unhalogenated straight-chain alkyl group containing 1 to 12 carbon atoms, a halogenated or unhalogenated straight-chain alkoxy group containing 1 to 11 carbon atoms, Substitution, and one or more ring -CH= can be replaced by -N=; P1, P2 and P3 each independently represent a polymerizable group; Sp1, Sp2 and Sp3 each independently represent a spacer group or a single bond; Z1 and Z2 each independently represent -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CH2O-, -OCH2-, -CH2S-, -SCH2-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -(CH2) d -, -CF2CH2-, -CH2CF2-, -(CF2) d -, -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH-, -CH2CH2-CO-O-, -O-CO-CH2CH2-, -CHR 1 -、-CR 1 R 2 - or a single bond, where R 1 and R 2 Each independently represents a straight or branched alkyl group containing 1 to 12 carbon atoms, and d represents an integer of 1 to 4; X0 represents -O-, -S-, -CO-, -CF2-, -NH- or -NF-; a represents 0, 1 or 2, b represents 0 or 1, wherein when a represents 2, the ring The same or different, Z1 the same or different.

10. The liquid crystal composition according to claim 9, characterized in that: The weight percentage of the compound of the general formula F in the liquid crystal composition is 0.1%-30%; the weight percentage of the compound of the general formula N in the liquid crystal composition is 0.1%-70%; The weight percentage of the compound of the general formula M in the liquid crystal composition is 0.1%-70%; the weight percentage of the polymerizable compound of the general formula RM in the liquid crystal composition is 0.001%-5%.

11. The liquid crystal composition according to claim 4, characterized in that: The liquid crystal composition further comprises at least one additive.

12. A liquid crystal display device comprising the liquid crystal composition according to any one of claims 4 to 11.

Images