Compound, liquid crystal composition and uses of both

Abstract

Embodiments of the present application relate to the technical field of liquid crystals. Disclosed are a compound, a liquid crystal composition and uses of both, used for solving the technical problem of short service life of electronic devices caused by poor material performance and high material performance attenuation speed of liquid crystal materials. The compound has a structure as shown in formula (I), wherein X1 and X2 are each independently selected from hydrogen, deuterium, tritium, at least one halogen and at least one hydrocarbyl group, and at least one of X1 and X2 is not hydrogen. The compound has relatively high birefringence, relatively good dielectric anisotropy, relatively low rotational viscosity, relatively high clearing point, relatively good low-temperature stability and the like, and when the compound is applied as a liquid crystal compound, the performance attenuation speed of a liquid crystal material is low, so that the service life of an electronic device can be prolonged.

Description

Compound, liquid crystal composition and application thereof

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on September 6, 2023, with application number 202311148441.1 and application name “Compounds, Liquid Crystal Compositions and Their Applications”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of liquid crystal technology, and in particular to a compound, a liquid crystal composition, and applications of the compound and the liquid crystal composition. Background Art

[0003] Liquid crystal materials are already widely used in smartphones, tablets, televisions, automotive instruments, and other fields. Furthermore, they are also widely needed in 3D displays, optical communications, microwave antennas, lenses, and other fields. These applications require liquid crystal materials to support greater phase and dielectric modulation, faster switching speeds, and higher resolution.

[0004] Among them, the relationship between the phase modulation amount of the liquid crystal device and the birefringence and box thickness of the liquid crystal material used in the liquid crystal device is that, when the box thickness is constant, the greater the birefringence of the liquid crystal material, the greater the phase modulation amount of the liquid crystal device. The response time of the liquid crystal device is proportional to the rotational viscosity of the liquid crystal material used in the liquid crystal device, and inversely proportional to the elastic modulus of the liquid crystal material used in the liquid crystal device. Therefore, this series of application scenarios requires that the birefringence of the liquid crystal material is significantly higher than that of ordinary liquid crystals, while also taking into account sufficiently large dielectric anisotropy, low rotational viscosity, high clearing point, low temperature stability (not easy to crystallize at low temperatures) and voltage retention stability (not easy to decrease).

[0005] Although some related technologies provide liquid crystal materials with advantages such as high birefringence, their material properties are prone to degradation. Therefore, providing a liquid crystal material that balances high birefringence with material performance stability has become a technical problem that needs to be solved urgently.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide a compound, a liquid crystal composition, and the application of the compound and the liquid crystal composition in display devices, optical communication equipment, wireless communication equipment, lens devices, etc., which are used to solve the technical problem that the liquid crystal material has a low birefringence and a fast degradation rate of material performance, thereby resulting in a short service life of the equipment or device.

[0008] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0009] In a first aspect, a compound is provided, which has a structure shown in formula (I);

[0010] in:

[0011] X1 and X2 are each independently selected from hydrogen, deuterium, tritium, at least one halogen and at least one hydrocarbon group, and at least one of X1 and X2 is not hydrogen; R1 is selected from at least one hydrocarbon group; R2 is selected from at least one polar group and at least one hydrocarbon group; A1 and A2 are each independently selected from arylene, heteroarylene, cycloalkyl and heterocycloalkyl; Z1 is a connecting group or a chemical bond; Z2 is a connecting group or a chemical bond; a and b are integers.

[0012] The compound having the structure shown in formula (I) has a high birefringence, good dielectric anisotropy, low rotational viscosity, high clearing point, and good low-temperature stability, thereby meeting the requirements of electronic devices in fields such as smart terminals, automotive instruments, 3D displays, optical communications, microwave antennas, and lenses (variable focus), such as larger phase and dielectric modulation, faster switching speed, and higher resolution for liquid crystal materials. In addition, because at least one hydrogen on the lateral side of the thienothiophene structure in the compound structure is replaced, and the substituent is selected from deuterium, tritium, at least one halogen, and at least one hydrocarbon group, the presence of the substituent can improve the structural stability of the compound and reduce the reactivity of the compound, so that when the compound is used as a liquid crystal compound, the performance decay rate of the liquid crystal material can be reduced, thereby extending the service life of electronic devices (various liquid crystal devices or devices containing liquid crystal devices).

[0013] In combination with the first aspect, in a possible implementation of the first aspect, when X1 is selected from at least one hydrocarbon group, X1 is a linear structure, or has a branched structure.

[0014] In combination with the first aspect, in a possible implementation of the first aspect, when X2 is selected from at least one hydrocarbon group, X2 is a linear structure, or has a branched structure.

[0015] In combination with the first aspect, in a possible implementation of the first aspect, when X1 is selected from at least one hydrocarbon group, at least one hydrogen atom on X1 is replaced by a fluorine atom.

[0016] In combination with the first aspect, in a possible implementation of the first aspect, when X2 is selected from at least one hydrocarbon group, at least one hydrogen atom on X2 is replaced by a fluorine atom.

[0017] In combination with the first aspect, in a possible implementation of the first aspect, when X1 is selected from at least one hydrocarbon group, X1 includes 1-8 carbon atoms.

[0018] In combination with the first aspect, in a possible implementation of the first aspect, when X2 is selected from at least one hydrocarbon group, X2 includes 1-8 carbon atoms.

[0019] In combination with the first aspect, in a possible implementation of the first aspect, X1 and X2 are each independently an alkyl group, an alkoxy group, an alkenyl group, an alkenyloxy group, a cycloalkyl group, or a cycloalkenyl group.

[0020] In combination with the first aspect, in a possible implementation of the first aspect, the alkyl group includes 1-8 carbon atoms; the alkoxy group includes 1-7 carbon atoms; the alkenyl group includes 2-8 carbon atoms; the alkenyloxy group includes 2-7 carbon atoms; the cycloalkyl group includes 3-8 carbon atoms; and the cycloalkenyl group includes 3-8 carbon atoms.

[0021] In combination with the first aspect, in a possible implementation of the first aspect, at least one of X1 and X2 is a methyl group.

[0022] In combination with the first aspect, in a possible implementation of the first aspect, R1 and R2 are each independently selected from an alkyl group, an alkoxy group, an alkenyl group, an alkenyloxy group, an alkynyl group, or an alkynyloxy group having a linear or branched structure.

[0023] In combination with the first aspect, in a possible implementation of the first aspect, R1 and R2 each independently contain one or more of oxygen, sulfur, and nitrogen.

[0024] In combination with the first aspect, in a possible implementation of the first aspect, any hydrogen atom on R1 and / or R2 is optionally replaced by a deuterium atom, a tritium atom or a halogen atom.

[0025] In combination with the first aspect, in a possible implementation of the first aspect, any two non-adjacent carbon atoms in R1 and / or R2 are connected to form a cyclic ring structure.

[0026] In combination with the first aspect, in a possible implementation of the first aspect, R1 and R2 are each independently selected from an alkyl group of 1-20 carbon atoms, an alkoxy group, an alkenyl group of 2-20 carbon atoms, an alkenyloxy group, an alkynyl group, and an alkynyloxy group.

[0027] In combination with the first aspect, in a possible implementation of the first aspect, the at least one polar group includes F, Cl, Br, CN, NO2, SCN, NCS, NCSe, OCF3 and SF5.

[0028] In combination with the first aspect, in a possible implementation of the first aspect, at least one hydrogen atom on A1 and / or A2 is replaced by X3, and X3 is selected from deuterium, tritium, a halogen atom and at least one hydrocarbon group.

[0029] In combination with the first aspect, in a possible implementation of the first aspect, when X3 is selected from at least one hydrocarbon group, any hydrogen atom on X3 is replaced by a fluorine atom.

[0030] In combination with the first aspect, in a possible implementation of the first aspect, when X3 is selected from at least one hydrocarbon group, X3 is selected from linear or branched alkyl, alkoxy, alkenyl and alkenyloxy groups, as well as cycloalkyl and cycloalkenyl groups.

[0031] In conjunction with the first aspect, in a possible implementation of the first aspect, when X3 is selected from at least one hydrocarbon group, X3 is selected from a linear or branched alkyl group having 1 to 8 carbon atoms, a linear or branched alkoxy group having 1 to 7 carbon atoms, a linear or branched alkenyl group having 2 to 8 carbon atoms, a linear or branched alkenyloxy group having 2 to 7 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, and a cycloalkenyl group having 3 to 8 carbon atoms. Optionally, any hydrogen atom on the alkyl, alkoxy, alkenyl, alkenyloxy, and cycloalkenyl group is substituted with a fluorine atom.

[0032] In combination with the first aspect, in a possible implementation of the first aspect, the arylene group includes 6-60 carbon atoms; the heteroarylene group includes 2-60 carbon atoms; the cycloalkylene group includes 3-60 carbon atoms; and the heterocycloalkylene group includes 1-60 carbon atoms.

[0033] In combination with the first aspect, in a possible implementation of the first aspect, when there are multiple A1s in formula (I), the multiple A1s are the same or different; when there are multiple A2s in formula (I), the multiple A2s are the same or different.

[0034] In combination with the first aspect, in a possible implementation of the first aspect, Z1 and Z2 are each independently selected from -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C≡C-, -C≡CC≡C-, -CO-O-, -O-CO, -CF2O-, -OCF2-, -CH2CH2-, -N=N-, -CH=N-, -N=CH-, -CH2O-, -OCH2-, -CF2CF2-, -CF2CH2-, -CH2CF2-.

[0035] In combination with the first aspect, in a possible implementation of the first aspect, a is selected from 0, 1, 2 and 3; b is selected from 0, 1, 2 and 3.

[0036] In a second aspect, a liquid crystal composition is provided, comprising any one of the compounds described above.

[0037] In a third aspect, there is provided a use of any one of the compounds in the first aspect, or the liquid crystal composition provided in the second aspect, in a display device, an optical communication device, a wireless communication device, and a lens device.

[0038] Among them, the technical effects brought about by any design method in the second to third aspects can refer to the technical effects brought about by different design methods in the first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG1 is a block diagram of an optical communication network according to some embodiments;

[0040] FIG2 is a block diagram of a wavelength selective switch according to some embodiments;

[0041] FIG3 is a structural diagram of an optical path modulation system according to some embodiments. DETAILED DESCRIPTION

[0042] The following describes the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings. In the description of the present application, unless otherwise specified, " / " indicates that the objects associated with each other are in an "or" relationship. For example, A / B can represent A or B. "And / or" in the present application is only a description of the association relationship between the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural.

[0043] Furthermore, in the description of this application, unless otherwise specified, "plurality" means two or more than two. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0044] At the same time, in the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner to facilitate understanding.

[0045] In addition, the liquid crystal devices and application scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field can know that with the evolution of liquid crystal devices and the emergence of new application scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0046] Before introducing the specific implementation of the technical solution of the present application, the terms involved in the embodiments of the present application are first explained.

[0047] Hydrocarbyl: From the perspective of atomic composition, hydrocarbon groups can include hydrocarbon groups composed of carbon and hydrogen, hydrocarbon groups composed of carbon, hydrogen, and oxygen, and hydrocarbon groups containing heteroatoms composed of carbon, hydrogen, and heteroatoms, where the heteroatoms can be oxygen, sulfur, and nitrogen. In addition, hydrocarbon groups can also include substituted hydrocarbon groups in which one or more hydrogen atoms are replaced by halogen atoms, for example. From the perspective of group structure, hydrocarbon groups can be chain structures or cyclic structures. The so-called chain structure can include a straight chain structure or a branched chain structure (also called a branched chain structure). From the perspective of saturation, hydrocarbon groups can include saturated hydrocarbon groups and unsaturated hydrocarbon groups.

[0048] Polar group: An organic part in which the electron distribution in the molecule does not produce a significant electric dipole moment. This group exhibits an affinity for low-polarity organic solvents and determines the oleophilic nature of the molecule.

[0049] As described in the background, an increasing number of applications require liquid crystal materials to possess high birefringence, along with sufficiently high dielectric anisotropy, low rotational viscosity, a high clearing point, low-temperature stability (resistance to crystallization at low temperatures), and voltage retention stability (resistance to degradation). However, these materials are prone to degradation, making performance stability difficult to guarantee.

[0050] In view of this, embodiments of the present application provide a compound, a liquid crystal composition (also referred to as a liquid crystal material) containing the compound, and an electronic device containing the liquid crystal material. The liquid crystal material exhibits material properties such as a high birefringence (Δn), good dielectric anisotropy (Δε), a low rotational viscosity (γ1), a high clearing point, low-temperature stability (hard to crystallize at low temperatures), and voltage retention stability, while also exhibiting high material performance stability.

[0051] The compounds provided in the embodiments of the present application or the liquid crystal compositions containing the compounds can be applied to application scenarios such as optical communication, wireless communication, microwave scanning antennas, lenses (such as variable focus lenses), gratings, lidar, beam tracking, projection, flat panel displays and holographic displays. The electronic devices provided in the embodiments of the present application include but are not limited to electronic devices in the aforementioned application scenarios.

[0052] For example, the electronic device can be, for example, a mobile phone, a tablet computer, a personal digital assistant (PDA), a laser TV, a projector, a smart wearable product (for example, a smart watch, a smart bracelet), a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a rechargeable small household appliance, a drone, a radar, an aerospace equipment, and a vehicle-mounted device, and other different types of user equipment or terminal devices; the electronic device can also be a wavelength selective switch (WSS) and other optical communication equipment, wireless communication equipment, a microwave scanning antenna, a lens device, a grating element, a laser radar element, a beam tracker, a projector, a holographic polymer dispersed liquid crystal device, a flat panel display, and a holographic display. The embodiments of the present application do not impose any special restrictions on the specific form of the electronic device.

[0053] Taking the electronic device as a wavelength selective switch as an example, FIG1 is a structural diagram of an optical communication network according to some embodiments; FIG2 is a structural diagram of a wavelength selective switch according to some embodiments.

[0054] Referring to Figures 1 and 2 , a wavelength selective switch 1 can be widely used at key nodes in optical communication networks, such as intercity networks or long-distance trunk lines, to enable data upload and download by scheduling the wavelengths of optical signals. Specifically, the wavelength selective switch 1 can independently schedule and control optical signals of different wavelengths in the input optical fiber (common port) and arbitrarily dispatch optical signals of different wavelengths to different output optical fibers (output ports).

[0055] The wavelength selective switch 1 includes an optical path modulation system 2 and a spectroscopic lens 3 as shown in FIG3 . Referring to FIG3 , the optical path modulation system 2 includes a liquid crystal on silicon (LCS) chip 4, an opposing substrate 5, a liquid crystal layer 6, and a flexible printed circuit (FPC) 7. The LCS chip 4 can be electrically connected to the flexible printed circuit 7 via bonding wires 8. The LCS chip 4 is disposed on the flexible printed circuit 7 and includes a pixel electrode 41 located on its upper surface. The opposing substrate 5 is disposed opposite the LCS chip 4 and includes a common electrode 52. A driving electric field can be formed between the common electrode 52 and the pixel electrode 41. The opposing substrate 5 also includes a substrate 51. The common electrode 52 is disposed on the substrate 51 and is located on the side of the substrate 51 that is adjacent to the LCS chip 4. The liquid crystal layer 6 is arranged between the silicon-based liquid crystal chip 4 and the opposing substrate 5. The liquid crystal molecules in the liquid crystal layer 6 can rotate under the drive of the driving electric field to adjust their reflectivity to light of different wavelengths, so that light of different wavelengths in the input optical fiber can be reflected at different output angles, thereby realizing the selective output of light, that is, realizing the independent scheduling and control of optical signals.

[0056] The liquid crystal layer 6 includes a liquid crystal composition, which may include compound A. The main chain structure of compound A includes a thienothiophene structure, and at least one hydrogen atom on the side of the thienothiophene structure is replaced by X, wherein X may be selected from deuterium, tritium, at least one halogen and at least one hydrocarbon group.

[0057] In some embodiments, the compound A has the structure shown in the following formula (I):

[0058] In the above formula (I), R1 is selected from at least one hydrocarbon group; R2 is selected from at least one polar group and at least one hydrocarbon group; A1 and A2 are each independently selected from an arylene group, a heteroarylene group, a cycloalkylene group and a heterocycloalkylene group; Z1 is a connecting group or a chemical bond for connecting A1 to the thienothiophene structure; Z2 is a connecting group or a chemical bond for connecting A2 to the thienothiophene structure; a and b are integers.

[0059] As can be seen from the above formula (I), the main chain of the compound is composed of a thienothiophene structure, A1, A2, R1, R2, Z1, and Z2. X1 and X2 are present laterally in the thienothiophene structure, and X1 and X2 are each independently selected from hydrogen, deuterium, tritium, at least one halogen, and at least one hydrocarbon group; at least one of X1 and X2 is not hydrogen. That is, when X1 is hydrogen, X2 is not hydrogen, and one hydrogen atom in the thienothiophene structure is replaced by X2. When X2 is hydrogen, X1 is not hydrogen, and one hydrogen atom in the thienothiophene structure is replaced by X1. When both X1 and X2 are not hydrogen, two hydrogen atoms in the thienothiophene structure are replaced by X1 and X2, respectively.

[0060] The compound having the structure shown in formula (I) has a high birefringence, good dielectric anisotropy, low rotational viscosity, a high clearing point, and good low-temperature stability, thereby meeting the requirements for liquid crystal materials in fields such as smart terminals, automotive instruments, 3D displays, optical communications, microwave antennas, and lenses, such as greater phase and dielectric modulation, faster switching speed, and higher resolution. In addition, because at least one hydrogen on the lateral side of the thienothiophene structure in the compound structure is replaced with a substituent selected from deuterium, tritium, at least one halogen, and at least one hydrocarbon group, the presence of the substituent can improve the structural stability of the compound and reduce the reactivity of the compound. Therefore, when the compound is used as a liquid crystal compound, it can reduce the performance degradation rate of the liquid crystal material, thereby extending the service life of electronic devices (various liquid crystal devices or devices containing liquid crystal devices).

[0061] In some embodiments, when X1 and X2 are each independently selected from at least one hydrocarbon group, X1 and X2 are each independently a linear structure, or a branched structure. For ease of description, a hydrocarbon group having a branched structure is referred to as a branched hydrocarbon group. For example, X1 and X2 are each independently a linear or branched alkyl group, an alkoxy group, an alkenyl group, an alkenyloxy group, a cycloalkyl group, or a cycloalkenyl group.

[0062] In some embodiments, when X1 and X2 are each independently selected from at least one hydrocarbon group, at least one hydrogen atom on X1 and / or X2 is replaced by a fluorine atom. For example, X1 and X2 are each independently a linear or branched alkyl, alkoxy, alkenyl, alkenyloxy, cycloalkyl or cycloalkenyl group, wherein at least one hydrogen atom on the alkyl, alkoxy, alkenyl, alkenyloxy, cycloalkyl and cycloalkenyl group is replaced by a fluorine atom. In these embodiments, since at least one hydrogen atom on X1 and / or X2 is replaced by a fluorine atom, the dielectric properties of the compound can be increased, the solubility of the compound can be improved, and the viscosity of the compound can be reduced. Thus, when the compound is applied to prepare a liquid crystal composition, the liquid crystal composition can be made to have a larger phase and dielectric modulation amount, a faster switching speed and a higher resolution, etc.

[0063] In some embodiments, when X1 and X2 are each independently selected from at least one hydrocarbon group, X1 and X2 each independently include 1-8 carbon atoms. For example, X1 and X2 each independently include: a straight-chain or branched alkyl group having 1-8 carbon atoms, a straight-chain or branched alkoxy group having 1-7 carbon atoms, a straight-chain or branched alkenyl group having 2-8 carbon atoms, a straight-chain or branched alkenyloxy group having 2-7 carbon atoms, a straight-chain or branched cycloalkyl group having 3-8 carbon atoms, or a straight-chain or branched cycloalkenyl group having 3-8 carbon atoms. In these embodiments, since X1 and X2 each independently include 1-8 carbon atoms, the viscosity and solubility of the compound can be within a preferred range.

[0064] In some embodiments, at least one of X1 and X2 is a methyl group. Specifically, when X1 is a methyl group, X2 can be selected from hydrogen, deuterium, tritium, at least one halogen, and at least one hydrocarbon group mentioned in the above embodiments. When X2 is a methyl group, X1 can be selected from hydrogen, deuterium, tritium, at least one halogen, and at least one hydrocarbon group mentioned in the above embodiments. Of course, X1 and X2 can both be methyl groups. In these embodiments, since at least one of X1 and X2 is a methyl group, the low-temperature stability of the compound can be improved. For example, crystallization is less likely to occur at lower temperatures, or the critical temperature for crystallization is lower.

[0065] It should be noted that the various implementations of X1 and X2 mentioned in the above embodiments are merely illustrative and do not limit the embodiments of the present application. It should be noted that in the structure of Compound A provided in the embodiments of the present application, X1 and X2 can be any one of hydrogen, deuterium, tritium, at least one halogen, and at least one hydrocarbon group, and these are not listed here.

[0066] In some embodiments, R1 and R2 are each independently a linear or branched structure. For example, R1 and R2 are each independently selected from a linear or branched alkyl, alkoxy, alkenyl, alkenyloxy, alkynyl, or alkynyloxy group.

[0067] Optionally, R1 and R2 each independently contain heteroatoms, such as one or more of oxygen, sulfur, and nitrogen. For example, R1 and R2 each independently contain linear or branched alkyl, alkoxy, alkenyl, alkenyloxy, alkynyl, and alkynyloxy groups containing one or more of oxygen, sulfur, and nitrogen.

[0068] Optionally, any hydrogen atom on R1 and / or R2 is optionally substituted by a deuterium atom, a tritium atom, or a halogen atom. For example, R1 and R2 are each independently selected from a linear or branched alkyl group, an alkoxy group, an alkenyl group, an alkenyloxy group, an alkynyl group, or an alkynyloxy group, wherein any hydrogen atom on R1 and / or R2 is optionally substituted by a deuterium atom, a tritium atom, or a halogen atom.

[0069] Optionally, any two non-adjacent carbon atoms on R1 and / or R2 are connected to form a cyclic structure. For example, R1 and R2 are each independently selected from a linear or branched alkyl, alkoxy, alkenyl, alkenyloxy, alkynyl, alkynyloxy group, and any two non-adjacent carbon atoms in the alkyl, alkoxy, alkenyl, alkenyloxy, alkynyl, alkynyloxy group are connected to form a cyclic ring structure. Wherein, the alkyl and alkoxy groups may include 1-20 carbon atoms; the alkenyl, alkenyloxy, alkynyl and alkynyloxy groups may include 2-20 carbon atoms. In these embodiments, the cyclic structure can increase the order of molecular stacking, thereby improving the dielectric anisotropy of the compound. In addition, since the hydrocarbon groups selected from R1 and R2 contain 1-20 carbon atoms, the viscosity and solubility of the compound can be within a preferred range.

[0070] In some examples, R1 and R2 are each independently selected from: a linear or branched alkyl or alkoxy group having 1 to 20 carbon atoms, a linear or branched alkenyl group, an alkenyloxy group, an alkynyl group, and an alkynyloxy group having 2 to 20 carbon atoms. The alkyl, alkoxy, alkenyl, alkenyloxy, alkynyl, and alkynyloxy groups may optionally contain one or more heteroatoms such as oxygen, sulfur, and nitrogen; any hydrogen atom on the alkyl, alkoxy, alkenyl, alkenyloxy, alkynyl, and alkynyloxy groups may optionally be substituted with a deuterium atom, a tritium atom, or a halogen atom; and any two non-adjacent carbon atoms in the alkyl, alkoxy, alkenyl, alkenyloxy, alkynyl, and alkynyloxy groups are linked to form a cyclic ring structure.

[0071] In one embodiment, R1 is selected from the following structures:

[0072] In some embodiments, R2 is selected from polar groups including F, Cl, Br, CN, NO2, SCN, NCS, NCSe, OCF3 and SF5.

[0073] It should be noted that the various implementations of R1 and R2 mentioned in the above embodiments are merely illustrative and do not constitute limitations on the embodiments of this application. It should be noted that in the structure of Compound A provided in the embodiments of this application, R1 can be any of at least one hydrocarbon group; and R2 can be any of at least one polar group and at least one hydrocarbon group, and these are not listed here.

[0074] In some embodiments, A1 and A2 are each independently selected from an arylene group containing 6-60 carbon atoms, a heteroarylene group containing 2-60 carbon atoms, a cycloalkylene group containing 3-60 carbon atoms, and a heterocycloalkylene group containing 1-60 carbon atoms. In these embodiments, since the arylene group contains 6-60 carbon atoms, the heteroarylene group contains 2-60 carbon atoms, the cycloalkylene group contains 3-60 carbon atoms, and the heterocycloalkylene group contains 1-60 carbon atoms, the size of the ring structure can be ensured to be within a preferred range, thereby ensuring the low-temperature stability of the compound and making it difficult to crystallize in a low-temperature environment.

[0075] In some embodiments, at least one hydrogen atom on A1 and / or A2 is replaced by X3. X3 is selected from deuterium, tritium, a halogen atom, and at least one hydrocarbon group. Wherein, if A1 and A2 each independently have multiple hydrogen atoms replaced by X3, then the multiple X3 replacing the multiple hydrogen atoms may be the same or different. For example, A1 and A2 each independently are selected from an arylene group containing 6-60 carbon atoms and at least one hydrogen atom replaced by X3, a heteroarylene group containing 2-60 carbon atoms and at least one hydrogen atom replaced by X3, a cycloalkylene group containing 3-60 carbon atoms and at least one hydrogen atom replaced by X3, and a heterocycloalkylene group containing 1-60 carbon atoms and at least one hydrogen atom replaced by X3.

[0076] In some embodiments, when X3 is selected from at least one hydrocarbon group, X3 can be specifically selected from a linear or branched alkyl group having 1 to 8 carbon atoms, a linear or branched alkoxy group having 1 to 7 carbon atoms, a linear or branched alkenyl group having 2 to 8 carbon atoms, a linear or branched alkenyloxy group having 2 to 7 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, and a cycloalkenyl group having 3 to 8 carbon atoms. Optionally, any hydrogen atom on the alkyl, alkoxy, alkenyl, alkenyloxy, and cycloalkenyl group is substituted with a fluorine atom.

[0077] In some embodiments, when there are multiple A1s in formula (I), that is, when a is greater than zero, the multiple A1s are the same or different; when there is A2 in formula (I), that is, when b is greater than zero, the multiple A2s are the same or different.

[0078] In some specific examples, A1 and A2 are each independently selected from 1,4-phenylene, 1,3-phenylene, 1,4-naphthylene, 2,6-naphthylene, 1,3-naphthylene, 1,5-naphthylene; 2,5-furylene, 2,4-furylene, 2,5-thienylene, 2,4-thienylene, 2,5-selenophene, 2,4-selenophene, 2,5-benzofuranyl, 2,6-benzofuranyl, 2,5-phenylene thiophene, 2,6-benzothiophene, 2,5-benzoselenophene, 2,6-benzoselenophene, 3,7-dibenzofuranyl, 2,6-dibenzofuranyl, 2,7-dibenzofuranyl, 3,7-dibenzothiophene, 2,6-dibenzothiophene, 2,7-dibenzothiophene, 3,7-dibenzoselenophene, 2,6-dibenzoselenophene, 2,7-dibenzoselenophene, 2,5-dibenzothiophene pheno[3,2-b]thienyl, 2,5-selenopheno[3,2-b]selenopheno[3,2-b]thienyl, 2,5-selenopheno[3,2-b]thienyl, 2,5-pyridylene, 2,5-pyrimidylene, 2,5-pyrazinylene, 3,6-pyridazinylene, 2,6-quinolylene, 3,7-quinolylene, 4,8-quinolylene, 5,8-quinolylene, 1,4-isoquinolylene, 1,5-isoquinolylene, 3,7-isoquinolylene 、4,8-isoquinolylene, 5,8-isoquinolylene, 5,8-quinoxalinylene;cis-1,4-cyclohexylene, trans-1,4-cyclohexylene, 1,4-cyclohexenylene, bicyclo[2.2.2]octane-1,4-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, 5,6,7,8-tetrahydronaphthalene-1,4-diyl, decahydronaphthalene-2,6-diyl, 2,3-dihydro-1H-indene-2,5-diyl. Optionally, one -CH2- or two or more non-adjacent -CH2- in the aforementioned groups may each independently be substituted by -O- or -S-. A1 and A2 provided herein are merely examples and do not constitute a limitation on the embodiments of the present application.

[0079] In some embodiments, Z1 and Z2 are each independently selected from -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C≡C-, -C≡CC≡C-, -CO-O-, -O-CO, -CF2O-, -OCF2-, -CH2CH2-, -N=N-, -CH=N-, -N=CH-, -CH2O-, -OCH2-, -CF2CF2-, -CF2CH2-, -CH2CF2-.

[0080] It should be noted that the various implementations of Z1 and Z2 mentioned in the above embodiments are merely examples and do not limit the embodiments of this application. It should be noted that Z1 provided in the embodiments of this application can be any linking group or chemical bond used to connect A1 to the thienothiophene structure, and these are not listed here. Z2 can be any linking group or chemical bond used to connect A2 to the thienothiophene structure, and these are not listed here.

[0081] In some embodiments, a is selected from 0, 1, 2, and 3; and b is selected from 0, 1, 2, and 3. In these embodiments, since a and b are both less than or equal to 3, the main chain structure of the compound can be ensured to be within an optimal range, thereby ensuring the viscosity and solubility of the compound, and ensuring the low-temperature stability of the liquid crystal composition.

[0082] The following describes the compounds provided in the examples of the present application and the liquid crystal compositions containing the compounds through specific examples, and tests the properties of the compounds and liquid crystal compositions prepared in the specific examples.

[0083] Example 1

[0084] (1) Preparation of 2-bromo-3-methyl-5-(4-propylphenyl)thieno[3,2-b]thiophene, referred to as "A-1-C".

[0085] Specifically, 5.2 g (14.50 mmol) (referred to as "A-1-A"), 840 mg (0.7 mmol) of tetrakistriphenylphosphine palladium (referred to as Pd(PPh3)4), and 6.14 g (29 mmol) of potassium phosphate (referred to as K3PO4) were added to a three-necked flask (250 mL), the system was kept closed, and the gas in the three-necked flask was replaced with argon. 13 mL of water and 52 mL of toluene were then added to react. After the reaction temperature was raised to 75°C, 2.85 g (17.4 mmol) of a substance dissolved in dimethyl sulfoxide (referred to as DMSO) (referred to as "A-1-B") was slowly added using an automatic sampler and reacted for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered through silica gel, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spin-dried, and then purified by column chromatography using n-hexane as the eluent to obtain 4.45 g of "A-1-C" as a white solid with a chromatographic purity (hereinafter referred to as GC purity) of 99.6%.

[0086] (2) Prepare 2-[(4-butyl-2,6-difluorophenyl)ethynyl]-3-methyl-5-(4-propylphenyl)thieno[3,2-b]thiophene, referred to as "A-1".

[0087] Specifically, 4.45g (12.67mmol) of substance "A-1-C", 278mg (0.38mmol) [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (abbreviated as Pd(dppf)Cl2), and 144mg (0.76mmol) of copper iodide (abbreviated as CuI) were added to a three-necked flask (250mL), the system was kept closed, and the gas in the three-necked flask was replaced with argon. 2.95g (15.2mmol) of raw material "A-1-D", 20mL of diisopropylamine, and 60mL of DMSO were added, and the reaction was carried out under a closed argon environment. The reaction temperature was raised to 120°C and the reaction was continued for 3 hours. After the reaction was completed, it was cooled to room temperature, filtered through silica gel, washed with water twice, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spun dry, and then purified by column chromatography using n-hexane as an eluent to obtain a pale yellow solid. The solid was further slurried with methanol to obtain 4.45 g of substance "A-1" with a GC purity of 99.98% and a gas chromatography-mass spectrometry (hereinafter referred to as GC-MS) (EI) m / z = 464.

[0088] The reaction process described in (1) and (2) in the above embodiment 1 can be shown as follows:

[0089] In summary, the structural formula of compound A provided in Example 1 of the present application is:

[0090] Example 2

[0091] (1) Preparation of 3-methyl-2-{[4-(4-pentylphenyl)phenyl]ethynyl}thieno[3,2-b]thiophene, referred to as "A-2-C".

[0092] Specifically, in a three-necked flask (500 mL), the raw material "A-2-B" (9.1 g, 36.9 mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (abbreviated as Pd(dppf)Cl2) (808 mg, 1.1 mmol), and copper iodide (abbreviated as CuI) (421 mg, 2.2 mmol) were added. The system was kept sealed and the gas in the three-necked flask was replaced with argon. The raw material "A-2-A" (8.6 g, 36.9 mmol), diisopropylamine (20 mL), and DMSO (172 mL) were added. After the reaction temperature was raised to 120°C, the reaction was continued for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered through silica gel, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spun dry, and then purified by column chromatography using n-hexane as an eluent to obtain a light yellow solid. The solid was further slurried with methanol to obtain 12.16 g of substance "A-2-C" with a GC purity of 99.9%.

[0093] (2) Preparation of 3-methyl-2-{[4-(4-pentylphenyl)phenyl]ethynyl}-5-propylthieno[3,2-b]thiophene, referred to as "A-2".

[0094] Specifically, add raw material "A-2-C" (8 g, 20 mmol) to a three-necked flask (500 mL). Keep the system sealed and replace the gas in the flask with argon. Add tetrahydrofuran (THF) (240 mL), stir to dissolve, place in a -78°C low-temperature reactor, stir for 0.5 h, add lithium diisopropylamide (LDA) (18 mL, 36 mmol) dropwise, and react for 3 h. Add A-2-D (6.11 g, 36 mmol) dropwise, warm to room temperature, and react for 1 h. The reaction was quenched with a saturated aqueous ammonium chloride solution, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and a saturated aqueous sodium chloride solution, and dried over anhydrous sodium sulfate. After filtration and spin-drying, column chromatography was performed using n-hexane as an eluent to separate and purify the product to obtain a white solid. The product was further recrystallized and slurried multiple times with an ethyl acetate / methanol mixed solution to obtain 6.8 g of substance "A-2" with a GC purity of 99.9% and GC-MS (EI) m / z = 442.

[0095] The reaction processes of (1) and (2) in the above embodiment 2 are shown below:

[0096] In summary, the structural formula of compound A provided in Example 2 of the present application is:

[0097] Example 3

[0098] (1) Preparation of 2-{[4-(4-butylphenyl)phenyl]ethynyl}-3-methylthieno[3,2-b]thiophene, referred to as "A-3-C".

[0099] Specifically, to a 500 mL three-necked flask, add the raw material "A-3-B" (7.2 g, 31.1 mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (Pd(dppf)Cl2) (452 ​​mg, 0.6 mmol), and copper iodide (CuI) (235 mg, 1.2 mmol). Keep the system sealed and replace the gas in the three-necked flask with argon. Then add the raw material "A-3-A" (7.2 g, 31.1 mmol), diisopropylamine (18 mL), and DMSO (150 mL). After heating to 120°C, continue the reaction for 3 hours. After completion of the reaction, cool to room temperature, filter through silica gel, wash twice with water, and extract with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spun dry, and then purified by column chromatography using n-hexane as an eluent to obtain a white solid. The solid was further slurried with methanol to obtain 9.93 g of substance "A-3-C" with a GC purity of 99.9%.

[0100] (2) Preparation of 3-methyl-2-{[4-(4-pentylphenyl)phenyl]ethynyl}-5-propylthieno[3,2-b]thiophene, referred to as "A-3"

[0101] Specifically, add raw material "A-3-C" (8 g, 20.7 mmol) to a three-necked flask (500 mL). Keep the system sealed and replace the gas in the flask with argon. Add tetrahydrofuran (THF) (160 mL) and stir to dissolve. Place in a -78°C low-temperature reactor and stir for 0.5 h. Add lithium diisopropylamide (LDA) (21.7 mL, 43.4 mmol) dropwise and react for 3 h. Add "A-3-D" (7.4 g, 43.4 mmol) dropwise, warm to room temperature, and react for 1 h. The reaction was quenched with a saturated aqueous ammonium chloride solution, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spin-dried, and then purified by column chromatography using n-hexane as an eluent to obtain a white solid. The solid was further recrystallized and slurried multiple times with an ethyl acetate / methanol mixed solution to obtain 4.14 g of "A-3" with a GC purity of 99.9% and GC-MS (EI) m / z = 428.

[0102] The reaction processes of (1) and (2) in the above embodiment 3 are shown below:

[0103] In summary, the structural formula of Compound A provided in Example 3 of the present application is:

[0104] Example 4

[0105] (1) Preparation of 2-bromo-3-methyl-5-(4-pentylphenyl)thieno[3,2-b]thiophene, referred to as "A-4-C".

[0106] Specifically, in a three-necked flask (250 mL), the raw material "A-4-A" (5.5 g, 15.318 mmol), tetrakis(triphenylphosphine)palladium (abbreviated as Pd(PPh3)4) (885 mg, 0.76 mmol), potassium phosphate (abbreviated as K3PO4) (6.5 g, 30.6 mmol) were added, and the gas in the three-necked flask was replaced with argon. Water (25 mL) and toluene (100 mL) were added. After the reaction temperature was raised to 75°C, "A-4-B" (3.53 g, 18.38 mmol) dissolved in dimethyl sulfoxide (abbreviated as DMSO) was slowly added using an automatic sampler and reacted for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered through silica gel, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spin-dried, and then purified by column chromatography using n-hexane as the eluent to obtain 5.3 g of "A-4-C" as a white solid with a GC purity of 99%.

[0107] (2) Preparation of 3-methyl-5-(4-pentylphenyl)-2-[(4-propylphenyl)ethynyl]thieno[3,2-b]thiophene, referred to as "A-4".

[0108] Specifically, in a three-necked flask (500 mL), the raw material "A-4-C" (5.3 g, 13.99 mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (abbreviated as Pd(dppf)Cl2) (306 mg, 0.419 mmol), and copper iodide (abbreviated as CuI) (159 mg, 0.839 mmol) were added. The system was kept sealed and the gas in the three-necked flask was replaced with argon. The raw material "A-4-D" (2.42 g, 16.79 mmol), diisopropylamine (20 mL), and DMSO (150 mL) were added. After the reaction temperature was raised to 120°C, the reaction was continued for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered through silica gel, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spun dry, and then purified by column chromatography using n-hexane as an eluent to obtain a pale yellow solid. The solid was further slurried with methanol to obtain 4.68 g of substance "A-4" with a GC purity of 99.9% and GC-MS (EI) m / z = 442.

[0109] The reaction processes of (1) and (2) in the above embodiment 4 are shown below:

[0110] In summary, the structural formula of compound A provided in Example 4 of the present application is:

[0111] Example 5

[0112] (1) Prepare 2-bromo-3-methyl-5-(3,4,5-trifluoro-4λ5,5λ5-cyclohexa-1,3,4,5-tetraenyl)thieno[3,2-b]thiophene, referred to as "A-5-C".

[0113] Specifically, in a three-necked flask (250 mL), the raw material "A-5-A" (5.5 g, 15.318 mmol), tetrakis(triphenylphosphine)palladium (abbreviated as Pd(PPh3)4) (885 mg, 0.76 mmol), potassium phosphate (abbreviated as K3PO4) (6.5 g, 30.6 mmol) were added, and the gas in the three-necked flask was replaced with argon. Water (25 mL) and toluene (100 mL) were added. The reaction temperature was raised to 75 ° C, and "A-5-B" (3.23 g, 18.38 mmol) dissolved in dimethyl sulfoxide (abbreviated as DMSO) was slowly added using an automatic sampler and reacted for 3 hours. After the reaction was completed, it was cooled to room temperature, filtered through silica gel, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spin-dried, and then purified by column chromatography using n-hexane as the eluent to obtain 2.7 g of "A-5-C" as a yellow solid with a GC purity of 96.5%.

[0114] (2) Prepare 3-methyl-2-[(4-pentylphenyl)ethynyl]-5-(3,4,5-trifluorophenyl)thieno[3,2-b]thiophene, referred to as "A-5".

[0115] Specifically, in a three-necked flask (250 mL), the raw material "A-5-C" (2.7 g, 7.43 mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (abbreviated as Pd(dppf)Cl2) (163 mg, 0.223 mmol), and copper iodide (abbreviated as CuI) (84.9 mg, 0.446 mmol) were added. The system was kept sealed and the gas in the three-necked flask was replaced with argon. The raw material "A-5-D" (1.66 g, 9.66 mmol), diisopropylamine (20 mL), and DMSO (80 mL) were added. The reaction temperature was raised to 120°C and the reaction was allowed to react for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered through silica gel, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spun dry, and then purified by column chromatography using n-hexane as an eluent to obtain a pale yellow solid. The solid was further slurried with methanol to obtain 2.7 g of substance "A-5" with a GC purity of 99.9% and GC-MS (EI) m / z = 454.

[0116] The reaction processes of (1) and (2) in the above embodiment 5 are shown below:

[0117] In summary, the structural formula of Compound A provided in Example 5 of the present application is:

[0118] Example 6

[0119] (1) Preparation of 3-methyl-2-{[4-(4-propylphenyl)phenyl]ethynyl}thieno[3,2-b]thiophene, referred to as "A-6-C"

[0120] Specifically, the raw material "A-6-B" (15.6 g, 70.8 mmol), [1,1'-bis(diphenylphosphino)ferrocene] dichloropalladium (abbreviated as Pd(dppf)Cl2) (1.0 g, 1.4 mmol), and copper iodide (abbreviated as CuI) (540 mg, 2.8 mmol) were added to a three-necked flask (500 mL). The system was kept sealed and the gas in the three-necked flask was replaced with argon. The raw material "A-6-A" (16.5 g, 70.8 mmol), diisopropylamine (40 mL), and DMSO (330 mL) were added. After the reaction temperature was raised to 120°C, the reaction was continued for 3 hours. After the reaction was completed, it was cooled to room temperature, filtered through silica gel, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spun dry, and then purified by column chromatography using n-hexane as an eluent to obtain a light yellow solid. The solid was further slurried with methanol to obtain 22.35 g of substance "A-6-C" with a GC purity of 99.6%.

[0121] (2) Preparation of 3-methyl-5-propyl-2-{[4-(4-propylphenyl)phenyl]ethynyl}thieno[3,2-b]thiophene, referred to as "A-6".

[0122] Specifically, add raw material "A-6-C" (11 g, 29.5 mmol) to a three-necked flask (500 mL), keep the system sealed, and replace the gas in the flask with argon. Add tetrahydrofuran (THF) (220 mL) and stir to dissolve. Place in a -78°C low-temperature reactor and stir for 0.5 h. Then, add lithium diisopropylamide (LDA) (29.5 mL, 59.1 mmol) dropwise and react for 3 h. Add "A-6-D" (10.0 g, 59.1 mmol) dropwise, warm to room temperature, and react for 1 h. The reaction was quenched with a saturated aqueous ammonium chloride solution, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and a saturated aqueous sodium chloride solution, and dried over anhydrous sodium sulfate. After filtration and spin-drying, column chromatography was performed using n-hexane as an eluent to separate and purify the product to obtain a white solid. The product was further recrystallized and slurried multiple times with an ethyl acetate / methanol mixed solution to obtain 6.26 g of substance "A-6" with a GC purity of 99.9% and GC-MS (EI) m / z = 414.

[0123] The reaction processes of (1) and (2) in the above Example 6 are shown below:

[0124] In summary, the structural formula of Compound A provided in Example 6 of the present application is:

[0125] Example 7

[0126] (1) Preparation of 3-methyl-2-{[4-(4-propylphenyl)phenyl]ethynyl}thieno[3,2-b]thiophene, referred to as "A-7-C".

[0127] Specifically, the raw material "A-7-B" (15.6 g, 70.8 mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (abbreviated as Pd(dppf)Cl2) (1.0 g, 1.4 mmol), and copper iodide (abbreviated as CuI) (540 mg, 2.8 mmol) were added to a three-necked flask (500 mL). The system was kept sealed and the gas in the three-necked flask was replaced with argon. The raw material "A-7-A" (16.5 g, 70.8 mmol), diisopropylamine (40 mL), and DMSO (330 mL) were added. After the reaction temperature was raised to 120°C, the reaction was continued for 3 hours. After the reaction was completed, it was cooled to room temperature, filtered through silica gel, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spun dry, and then purified by column chromatography using n-hexane as an eluent to obtain a light yellow solid. The solid was further slurried with methanol to obtain 22.35 g of substance "A-7-C" with a GC purity of 99.6%.

[0128] (2) Preparation of 5-ethyl-3-methyl-2-{[4-(4-propylphenyl)phenyl]ethynyl}thieno[3,2-b]thiophene, referred to as "A-7".

[0129] Specifically, add raw material "A-7-C" (11 g, 29.5 mmol) to a three-necked flask (500 mL), keep the system sealed, and replace the gas in the flask with argon. Add tetrahydrofuran (THF) (220 mL) and stir to dissolve. Place in a -78°C low-temperature reactor and stir for 0.5 h. Then, add lithium diisopropylamide (LDA) (29.5.7 mL, 59.1 mmol) dropwise and react for 3 h. Add "A-7-D" (9.2 g, 59.1 mmol) dropwise, warm to room temperature, and react for 1 h. The reaction was quenched with a saturated aqueous ammonium chloride solution, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and a saturated aqueous sodium chloride solution, and dried over anhydrous sodium sulfate. After filtration and spin-drying, column chromatography was performed using n-hexane as an eluent to separate and purify the obtained brown solid. The solid was further recrystallized and slurried multiple times with an ethyl acetate / methanol mixed solution to obtain 5.97 g of substance "A-7" with a GC purity of 99.9% and GC-MS (EI) m / z = 400.

[0130] The reaction processes of (1) and (2) in the above Example 7 are shown below:

[0131] In summary, the structural formula of Compound A provided in Example 7 of the present application is:

[0132] Example 8

[0133] (1) Prepare 2-bromo-5-(4-butylphenyl)-3-methylthieno[3,2-b]thiophene, referred to as "A-8-C".

[0134] Specifically, the raw material "A-8-A" (4.9 g, 13.6 mmol), tetrakis(triphenylphosphine)palladium (abbreviated as Pd(PPh3)4) (789 mg, 0.7 mmol), potassium phosphate (abbreviated as K3PO4) (5.8 g, 27.3 mmol) were added to a three-necked flask (250 mL), and the gas in the three-necked flask was replaced with argon. Water (25 mL) and toluene (100 mL) were added. The reaction temperature was raised to 75°C, and "A-8-B" (2.9 g, 16.4 mmol) dissolved in dimethyl sulfoxide (abbreviated as DMSO) was slowly added using an automatic sampler and reacted for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered through silica gel, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spin-dried, and then purified by column chromatography using n-hexane as the eluent to obtain 4.15 g of "A-8-C" as a white solid with a GC purity of 98.5%.

[0135] (2) Prepare 5-(4-butylphenyl)-3-methyl-2-[(4-propylphenyl)ethynyl]thieno[3,2-b]thiophene, referred to as "A-8".

[0136] Specifically, the raw material "A-8-C" (4.15 g, 11.4 mmol), [1,1'-bis(diphenylphosphino)ferrocene] dichloropalladium (abbreviated as Pd(dppf)Cl2) (249 mg, 0.3 mmol), and copper iodide (abbreviated as CuI) (131 mg, 0.7 mmol) were added to a three-necked flask (250 mL). The system was kept sealed and the gas in the three-necked flask was replaced with argon. The raw material "A-8-D" (1.97 g, 13.6 mmol), diisopropylamine (5 mL), and DMSO (100 mL) were added. After the reaction temperature was raised to 120°C, the reaction was continued for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered through silica gel, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spun dry, and then purified by column chromatography using n-hexane as an eluent to obtain a pale yellow solid. The solid was further slurried with methanol to obtain 3.92 g of substance "A-8" with a GC purity of 99.9% and GC-MS (EI) m / z = 428.

[0137] The reaction processes of (1) and (2) in Example 8 above are shown below:

[0138] In summary, the structural formula of Compound A provided in Example 8 of the present application is:

[0139] Example 9

[0140] (1) Preparation of 2-bromo-3-methyl-5-(4-propylphenyl)thieno[3,2-b]thiophene, referred to as "A-9-C".

[0141] Specifically, the raw material "A-9-A" (14 g, 38.99 mmol), tetrakis(triphenylphosphine)palladium (abbreviated as Pd(PPh3)4) (2.25 g, 1.94 mmol), and potassium phosphate (abbreviated as K3PO4) (16.5 g, 70.99 mmol) were added to a three-necked flask (500 mL). The gas in the three-necked flask was replaced with argon. Water (40 mL) and toluene (260 mL) were added. The reaction temperature was raised to 75°C, and "A-9-B" (7.67 g, 46.79 mmol) dissolved in dimethyl sulfoxide (abbreviated as DMSO) was slowly added using an automatic sampler and reacted for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered through silica gel, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spin-dried, and then purified by column chromatography using n-hexane as the eluent to obtain 11.89 g of a white solid "A-9-C" with a GC purity of 99.2%.

[0142] (2) Preparation of 3-methyl-5-(4-propylphenyl)-2-[(4-propylphenyl)ethynyl]thieno[3,2-b]thiophene, referred to as "A-9".

[0143] Specifically, in a three-necked flask (250 mL), the raw material "A-9-C" (5.9 g, 16.79 mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (abbreviated as Pd(dppf)Cl2) (368 mg, 0.503 mmol), and copper iodide (abbreviated as CuI) (191 mg, 1.007 mmol) were added. The system was kept sealed and the gas in the three-necked flask was replaced with argon. The raw material "A-9-D" (3.14 g, 21.83 mmol), diisopropylamine (20 mL), and DMSO (160 mL) were added. The reaction temperature was raised to 120°C and the reaction was allowed to react for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered through silica gel, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spun dry, and then purified by column chromatography using n-hexane as an eluent to obtain a yellow solid. The solid was further slurried with methanol to obtain 6.36 g of substance "A-9-C" with a GC purity of 99.9% and GC-MS (EI) m / z = 414.

[0144] The reaction processes of (1) and (2) in Example 9 above are shown below:

[0145] In summary, the structural formula of Compound A provided in Example 9 of the present application is:

[0146] Example 10

[0147] (1) 2-Bromo-3-methyl-5-(4-propylphenyl)thieno[3,2-b]thiophene, referred to as "A-10-C".

[0148] Specifically, the raw material "A-10-A" (14 g, 38.99 mmol), tetrakis(triphenylphosphine)palladium (abbreviated as Pd(PPh3)4) (2.25 g, 1.94 mmol), potassium phosphate (abbreviated as K3PO4) (16.5 g, 70.99 mmol) were added to a 500 mL three-necked flask, and the gas in the three-necked flask was replaced with argon. Water (40 mL) and toluene (260 mL) were added. The reaction temperature was raised to 75°C, and "A-10-B" (7.67 g, 46.79 mmol) dissolved in dimethyl sulfoxide (abbreviated as DMSO) was slowly added using an automatic sampler and reacted for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered through silica gel, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spin-dried, and then purified by column chromatography using n-hexane as the eluent to obtain 11.89 g of "A-10-C" as a white solid with a GC purity of 99.2%.

[0149] (2) Preparation of 2-[(4-ethylphenyl)ethynyl]-3-methyl-5-(4-propylphenyl)thieno[3,2-b]thiophene, referred to as "A-10".

[0150] Specifically, the raw material "A-10-C" (5.9 g, 16.79 mmol), [1,1'-bis(diphenylphosphino)ferrocene] dichloropalladium (abbreviated as Pd(dppf)Cl2) (368 mg, 0.503 mmol), and copper iodide (abbreviated as CuI) (191 mg, 1.007 mmol) were added to a 500 mL three-necked flask. The system was kept sealed and the gas in the three-necked flask was replaced with argon. The raw material "A-10-D" (2.84 g, 21.83 mmol), diisopropylamine (20 mL), and DMSO (160 mL) were added. After the reaction temperature was raised to 120°C, the reaction was continued for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered through silica gel, washed twice with water, and extracted with ethyl acetate to obtain an organic phase. The organic phase was washed twice with a saturated aqueous ammonium chloride solution and twice with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spun dry, and then purified by column chromatography using n-hexane as an eluent to obtain a yellow solid. The solid was further slurried with methanol to obtain 5.8 g of substance "A-10" with a GC purity of 99.9% and GC-MS (EI) m / z = 400.

[0151] The reaction processes of (1) and (2) in Example 10 above are shown below:

[0152] In summary, the structural formula of Compound A provided in Example 10 of the present application is:

[0153] The 10 compounds A provided in the above examples are merely examples and do not limit the present invention. The compounds A provided in the present invention can be any structure that conforms to the general formula shown in formula (I), and are not listed here one by one.

[0154] The birefringence Δn, dielectric anisotropy Δε and clearing point CP of the compounds (A-1, A-2, A-3, A-5) provided in the examples of the present application were tested.

[0155] Δn(589nm, 25℃)=n e (589nm, 25℃)-n o (589nm, 25℃). e (589nm, 25℃), n o (589 nm, 25°C) were measured using an ATAGO-DR-M4 Abbe refractometer.

[0156] Δε(1kHz, 25℃)=ε ∥ (1kHz, 25℃)-ε ⊥ (1kHz, 25℃). ε ∥ Represents the dielectric constant in the direction parallel to the liquid crystal, ε ⊥ Represents the dielectric constant in the vertical direction of the liquid crystal, ε ∥ (1kHz, 25℃) and ε ⊥ (1kHz, 25℃) were measured using the ALCT-IV1 liquid crystal comprehensive parameter tester.

[0157] CP, clearing point of liquid crystal; measured using a Mettler DSC3 differential scanning calorimeter under nitrogen atmosphere at a heating rate of 10°C / min, expressed in °C, and expressed as T NI (℃).

[0158] The test results are shown in Table 1.

[0159] Table 1

[0160] The compound A provided in the comparative example of the present application may have the following structure B-1.

[0161] The compound of structural formula A-1 was used as a liquid crystal monomer and dissolved in the matrix liquid crystal at a 10% mass percentage to obtain liquid crystal composition sample 1. The compound of structural formula B-1 provided in the comparative example was used as a liquid crystal monomer and dissolved in the matrix liquid crystal at a 10% mass percentage to obtain liquid crystal composition sample 2. The matrix liquid crystal was prepared by mixing monomers such as phenylcyclohexane, biphenylcyclohexane, and terphenyl.

[0162] The voltage holding ratio of liquid crystal composition sample 1 and liquid crystal composition sample 2 was tested using the following method. The test results are shown in Table 2.

[0163] First, liquid crystal composition sample 1 was poured into two TN-type liquid crystal cells with a cell thickness of 7 μm and sealed, obtaining liquid crystal cell samples 1 and 2. Liquid crystal composition sample 2 was poured into two TN-type liquid crystal cells with a cell thickness of 7 μm and sealed, obtaining liquid crystal cell samples 3 and 4.

[0164] Then, liquid crystal cell sample 1 was placed in a UV test chamber, and a 365nm light source was used to accumulate a set irradiation dose to perform UV aging treatment on liquid crystal composition sample 1. Liquid crystal cell sample 2 was placed in a high-temperature incubator with adjustable high and low temperatures, the temperature was set to 100°C, and after a preset baking time, the sample was removed, and liquid crystal composition sample 1 was subjected to high-temperature aging treatment. Liquid crystal cell sample 3 was placed in a UV test chamber, and a 365nm light source was used to accumulate a set irradiation dose to perform UV aging treatment on liquid crystal composition sample 2. Liquid crystal cell sample 4 was placed in a high-temperature incubator with adjustable high and low temperatures, the temperature was set to 100°C, and after a preset baking time, the sample was removed, and liquid crystal composition sample 2 was subjected to high-temperature aging treatment.

[0165] Finally, before and after aging, the voltage holding ratio (V HR ).

[0166] Table 2

[0167] As can be seen from the table above, compared with the compound structure B-1 given in the comparative example, the voltage holding ratio of the compound structure A-1 provided in the embodiment of the present application is reduced less, so the performance of the device containing the liquid crystal compound material of the present invention will also be more stable.

[0168] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention are intended to be covered by the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope of protection of the claims.

Claims

1. A compound, characterized in that The compound has a structure shown in formula (I); in: X1 and X2 are each independently selected from hydrogen, deuterium, tritium, at least one halogen, and at least one hydrocarbon group, and at least one of X1 and X2 is not hydrogen; R1 is selected from at least one hydrocarbon group; R2 is selected from at least one polar group and at least one hydrocarbon group; A1 and A2 are each independently selected from arylene, heteroarylene, cycloalkylene and heterocycloalkylene; Z1 and Z2 are each independently a linking group or a chemical bond; a and b are integers.

2. The compound according to claim 1, characterized in that When X1 is selected from at least one hydrocarbon group, X1 is a linear structure or has a branched structure; and / or, when X2 is selected from at least one hydrocarbon group, X2 is a linear structure or has a branched structure.

3. The compound according to claim 1 or 2, characterized in that When X1 is selected from at least one hydrocarbon group, at least one hydrogen atom on X1 is replaced by a fluorine atom; and / or, when X2 is selected from at least one hydrocarbon group, at least one hydrogen atom on X2 is replaced by a fluorine atom.

4. The compound according to any one of claims 1 to 3, characterized in that In the case where X1 is selected from at least one hydrocarbon group, X1 comprises 1-8 carbon atoms; and / or, in the case where X2 is selected from at least one hydrocarbon group, X2 comprises 1-8 carbon atoms.

5. The compound according to any one of claims 1 to 4, characterized in that The X1 and the X2 are each independently an alkyl group, an alkoxy group, an alkenyl group, an alkenyloxy group, a cycloalkyl group or a cycloalkenyl group.

6. The compound according to claim 5, characterized in that: The alkyl group includes 1 to 8 carbon atoms; The alkoxy group includes 1-7 carbon atoms; The alkenyl group includes 2-8 carbon atoms; The alkenyloxy group includes 2 to 7 carbon atoms; The cycloalkyl group includes 3 to 8 carbon atoms; The cycloalkenyl group comprises 3 to 8 carbon atoms.

7. The compound according to claim 1, characterized in that At least one of the X1 and the X2 is a methyl group.

8. The compound according to claim 1, characterized in that The R1 and R2 are each independently selected from a linear or branched alkyl, alkoxy, alkenyl, alkenyloxy, alkynyl, alkynyloxy group; The alkyl, alkoxy, alkenyl, alkenyloxy, alkynyl, and alkynyloxy groups contain one or more of oxygen, sulfur, and nitrogen; Any hydrogen atom on the alkyl, alkoxy, alkenyl, alkenyloxy, alkynyl, alkynyloxy group is optionally substituted by a deuterium atom, a tritium atom or a halogen atom; Any two non-adjacent carbon atoms in the alkyl, alkoxy, alkenyl, alkenyloxy, alkynyl and alkynyloxy groups are connected to form a cyclic ring structure.

9. The compound according to claim 8, characterized in that: The alkyl and alkoxy groups include 1 to 20 carbon atoms; The alkenyl, alkenyloxy, alkynyl and alkynyloxy groups contain 2 to 20 carbon atoms.

10. The compound according to any one of claims 1 to 9, characterized in that The at least one polar group includes F, Cl, Br, CN, NO2, SCN, NCS, NCSe, OCF3 and SF5.

11. The compound according to any one of claims 1 to 10, characterized in that At least one hydrogen atom on A1 and / or A2 is replaced by X3, and X3 is selected from deuterium, tritium, a halogen atom, a straight chain or branched chain alkyl group having 1 to 8 carbon atoms, a straight chain or branched chain alkoxy group having 1 to 7 carbon atoms, a straight chain or branched chain alkenyl group having 2 to 8 carbon atoms, a straight chain or branched chain alkenyloxy group having 2 to 7 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, and a cycloalkenyl group having 3 to 8 carbon atoms; Any hydrogen atom on the alkyl group, alkoxy group, alkenyl group, alkenyloxy group and cycloalkenyl group is substituted with a fluorine atom.

12. The compound according to claim 1 or 11, characterized in that: The arylene group includes 6 to 60 carbon atoms; The heteroarylene group includes 2 to 60 carbon atoms; The cycloalkylene group includes 3 to 60 carbon atoms; The heterocycloalkylene group includes 1 to 60 carbon atoms.

13. The compound according to any one of claims 1 to 12, characterized in that When there are multiple A1s in the formula (I), the multiple A1s are the same or different; when there are multiple A2s in the formula (I), the multiple A2s are the same or different.

14. The compound according to any one of claims 1 to 13, characterized in that The Z1 and Z2 are each independently selected from -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C≡C-, -C≡CC≡C-, -CO-O-, -O-CO, -CF2O-, -OCF2-, -CH2CH2-, -N=N-, -CH=N-, -N=CH-, -CH2O-, -OCH2-, -CF2CF2-, -CF2CH2-, -CH2CF2-.

15. The compound according to any one of claims 1 to 14, characterized in that The a is selected from 0, 1, 2 and 3; the b is selected from 0, 1, 2 and 3.

16. A liquid crystal composition, characterized in that: The invention comprises the compound as described in any one of claims 1 to 15.

17. Use of the compound according to any one of claims 1 to 15, or the composition according to claim 16 in a display device, an optical communication device, a wireless communication device and a lens device.

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