Compound, liquid crystal composition and application thereof

Abstract

The embodiment of the invention discloses a compound, a liquid crystal composition and application thereof, relates to the technical field of liquid crystals, and is used for solving the technical problem that the service life of electronic equipment is short due to the fact that a liquid crystal material is poor in material performance and high in material performance attenuation speed. The compound has a structure as shown in a formula (I). # imgabs0 # wherein X1 and X2 are each independently selected from the group consisting of 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 higher birefringence, better dielectric anisotropy, lower rotary viscosity, higher clearing point, better low-temperature stability and the like, and when the compound is used as a liquid crystal compound, the performance degradation speed of a liquid crystal material is slow, so that the service life of electronic equipment can be prolonged.

Description

Technical Field

[0001] 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

[0002] Liquid crystal materials have been widely used in smart phones, tablet devices, televisions, automotive instruments and other fields. Furthermore, there is also a wide demand for liquid crystal materials in 3D display, optical communication, microwave antennas, lenses and other fields. In this series of application scenarios, liquid crystal materials are required to support larger phase and dielectric modulation, faster switching speed and higher resolution.

[0003] 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 coefficient 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, lower rotational viscosity, higher clearing point, low temperature stability (not easy to crystallize at low temperature) and voltage retention rate stability (not easy to reduce), etc.

[0004] Although some related technologies provide liquid crystal materials with advantages such as high birefringence, their material properties are prone to attenuation. Therefore, providing a liquid crystal material that takes into account both high birefringence and material performance stability has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] The embodiments of the present application provide a compound, a liquid crystal composition, and the use of the compound and the liquid crystal composition in display devices, optical communication devices, wireless communication devices, lens devices, etc., for solving the technical problem that the liquid crystal material has a low birefringence and a fast material performance decay rate, which leads to a short service life of the equipment or device.

[0006] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0007] In a first aspect, a compound is provided, the compound having a structure shown in formula (I);

[0008] in:

[0009] 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 groups, heteroarylene groups, cycloalkylene groups and heterocycloalkylene groups; Z1 is a connecting group or a chemical bond; Z2 is a connecting group or a chemical bond; a and b are integers.

[0010] The compound having the structure shown in formula (I) has a higher birefringence, better dielectric anisotropy, lower rotational viscosity, higher clearing point and better low temperature stability, and can meet the requirements of electronic devices in the fields of intelligent terminals, vehicle instruments, 3D displays, optical communications, microwave antennas, lenses (variable focus), etc., for liquid crystal materials, such as larger phase and dielectric modulation, faster switching speed and higher resolution. In addition, since at least one hydrogen on the side of the thienothiophene structure in the compound structure is replaced, 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 the electronic device (various liquid crystal devices or devices containing liquid crystal devices).

[0011] 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.

[0012] 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.

[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, at least one hydrogen atom on X1 is replaced by a fluorine atom.

[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, at least one hydrogen atom on X2 is replaced by a fluorine atom.

[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, X1 includes 1-8 carbon atoms.

[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, X2 includes 1-8 carbon atoms.

[0017] 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.

[0018] 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.

[0019] In combination with the first aspect, in a possible implementation manner of the first aspect, at least one of X1 and X2 is a methyl group.

[0020] 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 with a linear structure or a branched structure.

[0021] In combination with the first aspect, in a possible implementation manner of the first aspect, R1 and R2 each independently contain one or more of oxygen, sulfur and nitrogen.

[0022] 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.

[0023] In combination with the first aspect, in a possible implementation manner of the first aspect, any two non-adjacent carbon atoms in R1 and / or R2 are connected to form a cyclic ring structure.

[0024] 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.

[0025] In combination with the first aspect, in a possible implementation of the first aspect, at least one polar group includes F, Cl, Br, CN, NO2, SCN, NCS, NCSe, OCF3 and SF5.

[0026] 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.

[0027] 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.

[0028] 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.

[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, X3 is selected from a linear or branched alkyl group with 1 to 8 carbon atoms, a linear or branched alkoxy group with 1 to 7 carbon atoms, a linear or branched alkenyl group with 2 to 8 carbon atoms, a linear or branched alkenyloxy group with 2 to 7 carbon atoms, a cycloalkyl group with 3 to 8 carbon atoms, and a cycloalkenyl group with 3 to 8 carbon atoms. Optionally, any hydrogen atom on the alkyl, alkoxy, alkenyl, alkenyloxy and cycloalkenyl group is substituted by a fluorine atom.

[0030] 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.

[0031] 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.

[0032] 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-.

[0033] In combination with the first aspect, in a possible implementation manner of the first aspect, a is selected from 0, 1, 2 and 3; b is selected from 0, 1, 2 and 3.

[0034] In a second aspect, a liquid crystal composition is provided, comprising any of the compounds described above.

[0035] 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.

[0036] Among them, the technical effects brought about by any design method in the second aspect to the third aspect 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

[0037] Figure 1 is a structural diagram of an optical communication network according to some embodiments;

[0038] Figure 2 is a structural diagram of a wavelength selective switch according to some embodiments;

[0039] Figure 3 is a structural diagram of an optical path modulation system according to some embodiments. DETAILED DESCRIPTION

[0040] The technical solution in the embodiment of the present application will be described below in conjunction with the drawings in the embodiment of the present application. In the description of the present application, unless otherwise specified, " / " indicates that the objects associated before and after 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 of 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, where A and B can be singular or plural.

[0041] 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 items 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 multiple.

[0042] Meanwhile, in the embodiments of the present 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 the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete manner for ease of understanding.

[0043] 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.

[0044] 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.

[0045] Hydrocarbyl: From the perspective of atomic composition, the hydrocarbon group 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, wherein the heteroatoms can be oxygen, sulfur and nitrogen. In addition, it can also include substituted hydrocarbon groups in which any one or more hydrogen atoms are replaced by halogen atoms. From the perspective of group structure, the hydrocarbon group can be a chain structure or a cyclic structure. The so-called chain structure can include a straight chain or a branched structure (also called a branched chain). From the perspective of saturation, the hydrocarbon group can include saturated hydrocarbon groups and unsaturated hydrocarbon groups.

[0046] Polar group: An organic part in which the electron distribution in the molecule does not produce a significant electric dipole moment. This group exhibits affinity for low-polarity organic solvents and determines the lipophilicity of the molecule.

[0047] As described in the background art, in more and more application scenarios, liquid crystal materials are required to have a high birefringence, and also to have sufficiently large dielectric anisotropy, low rotational viscosity, high clearing point, low temperature stability (not easy to crystallize at low temperature) and voltage holding rate stability (not easy to decrease), etc. However, its material properties are prone to attenuation, and the stability of performance is difficult to guarantee.

[0048] In view of this, the 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 has material properties such as a higher birefringence (Δn), better dielectric anisotropy (Δε), lower rotational viscosity (γ1), a higher clearing point, low temperature stability (not easy to crystallize at low temperature), and voltage retention rate stability, and has higher material performance stability.

[0049] 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.

[0050] For example, the electronic device can be a mobile phone, a tablet computer, a personal digital assistant (PDA), a laser TV, a projector, a smart wearable product (e.g., a smart watch, a smart bracelet), a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a charging small household appliance, a drone, a radar, an aerospace equipment, and a vehicle-mounted device, etc., and different types of user equipment or terminal equipment; the electronic device can also be a wavelength selective switch (WSS) and other optical communication equipment, wireless communication equipment, microwave scanning antenna, lens device, grating element, laser radar element, beam tracker, projector, holographic polymer dispersed liquid crystal device, flat panel display and holographic display. The embodiments of the present application do not impose any special restrictions on the specific form of the electronic device.

[0051] Taking the electronic device as a wavelength selective switch as an example, Figure 1 is a structural diagram of an optical communication network according to some embodiments; Figure 2 FIG. 4 is a block diagram of a wavelength selective switch according to some embodiments.

[0052] See also Figure 1 and Figure 2 The wavelength selective switch 1 can be widely used in key nodes in optical communication networks, for example, in intercity networks or long-distance trunk lines, to achieve data upload and download by scheduling the wavelength of the optical signal. 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 schedule optical signals of different wavelengths to different output optical fibers (output ports).

[0053] The wavelength selective switch 1 comprises: Figure 3 The optical path modulation system 2 and the beam splitter lens 3 are shown. Figure 3The optical path modulation system 2 includes a silicon-based liquid crystal chip 4, an opposing substrate 5, a liquid crystal layer 6, and a flexible printed circuit (FPC) 7. The silicon-based liquid crystal chip 4 can be electrically connected to the flexible printed circuit 7 through a welding wire 8. The silicon-based liquid crystal chip 4 is arranged on the flexible printed circuit 7, and the silicon-based liquid crystal chip 4 includes a pixel electrode 41 located on its upper surface. The opposing substrate 5 is arranged opposite to the silicon-based liquid crystal chip 4, and the opposing substrate 5 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, and the common electrode 52 is arranged on the substrate 51 and is located on a side of the substrate 51 close to the silicon-based liquid crystal 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 driving 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 exit angles, thereby realizing the selective output of light, that is, realizing the independent scheduling and control of optical signals.

[0054] 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.

[0055] In some embodiments, the compound A has a structure shown in the following formula (I):

[0056]

[0057] 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 used to connect A1 and the thienothiophene structure; Z2 is a connecting group or a chemical bond used to connect A2 and the thienothiophene structure; a and b are integers.

[0058] It can be seen from the above formula (I) that the main chain of the compound is composed of a thienothiophene structure, A1, A2, R1, R2, Z1 and Z2, and X1 and X2 are present on the side of the thienothiophene structure, and X1 and X2 are 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 on the side of the thienothiophene structure is replaced by X2. When X2 is hydrogen, X1 is not hydrogen, and one hydrogen atom on the thienothiophene structure is replaced by X1. When both X1 and X2 are not hydrogen, two hydrogen atoms on the side of the thienothiophene structure are replaced by X1 and X2, respectively.

[0059] The compound having the structure shown in formula (I) has a higher birefringence, better dielectric anisotropy, lower rotational viscosity, higher clearing point and better low temperature stability, and can meet the requirements of liquid crystal materials in fields such as intelligent terminals, automotive instruments, 3D displays, optical communications, microwave antennas, lenses, etc., such as larger phase and dielectric modulation, faster switching speed and higher resolution. In addition, since at least one hydrogen on the side of the thienothiophene structure in the compound structure is replaced, 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).

[0060] 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 have a branched structure. For ease of description, the 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, alkoxy, alkenyl, alkenyloxy, cycloalkyl or cycloalkenyl group.

[0061] 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 property 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 used to prepare a liquid crystal composition, the liquid crystal composition can have a larger phase and dielectric modulation amount, a faster switching speed and a higher resolution, etc.

[0062] 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, and 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.

[0063] 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 made better, for example, under low temperature conditions, crystallization is not easy to occur, or the critical temperature for crystallization is lower.

[0064] It should be noted that the various implementations of X1 and X2 mentioned in the above embodiments are only examples and do not constitute a limitation on 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, which are not listed one by one herein.

[0065] In some embodiments, R1 and R2 are each independently a linear structure or a branched structure. For example, R1 and R2 are each independently selected from a linear or branched alkyl, alkoxy, alkenyl, alkenyloxy, alkynyl, alkynyloxy.

[0066] 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 are selected from linear or branched alkyl, alkoxy, alkenyl, alkenyloxy, alkynyl, alkynyloxy.

[0067] 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, alkoxy, alkenyl, alkenyloxy, alkynyl, alkynyloxy group, in which any hydrogen atom is optionally substituted by a deuterium atom, a tritium atom or a halogen atom.

[0068] 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, and any two non-adjacent carbon atoms in the alkyl, alkoxy, alkenyl, alkenyloxy, alkynyl, alkynyloxy are connected to form a cyclic ring structure. Among them, 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.

[0069] 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 be optionally replaced 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.

[0070] In one specific example, R1 is selected from the following structures:

[0071]

[0072] In some embodiments, R2 is selected from the 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 only examples and do not constitute a limitation on 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, R1 can be any one of at least one hydrocarbon group; R2 can be any one of at least one polar group and at least one hydrocarbon group, which are not listed one by one in this article.

[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 cyclic structure can be ensured to be within a preferred range, thereby ensuring the low-temperature stability of the compound, 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 are each independently 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 X, a cycloalkyl group containing 3-60 carbon atoms and at least one hydrogen atom replaced by X3, and a heterocycloalkyl 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 by 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-furanylene, 2,4-furanylene, 2,5-thienylene, 2,4-thienylene, 2,5-selenophene, 2,4-selenophene, 2,5-benzofuranylene, 2,6-benzofuranylene, 2,5-phenylene 2,6-Benzothiphenylene, 2,5-Benzoselenophene, 2,6-Benzoselenophene, 3,7-Dibenzofuranyl, 2,6-Dibenzofuranyl, 2,7-Dibenzofuranyl, 3,7-Dibenzothiophenylene, 2,6-Dibenzothiophenylene, 2,7-Dibenzothiophenylene, 3,7-Dibenzoselenophene, 2,6-Dibenzoselenophene, 2,7-Dibenzoselenophene, 2,5-Dibenzothiophenylene 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-isoquinolyl, 5,8-isoquinolyl, 5,8-quinoxalyl; cis-1,4-cyclohexyl, trans-1,4-cyclohexyl, 1,4-cyclohexenyl, 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 be independently substituted by -O- or -S-. A1 and A2 provided herein are for illustrative purposes only and do not constitute limitations 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 only examples and do not constitute a limitation on the embodiments of the present application. It should be noted that Z1 provided in the embodiments of the present application can be any connecting group or chemical bond used to connect A1 and the thienothiophene structure, which will not be listed one by one in this article. Z2 can be any connecting group or chemical bond used to connect A2 and the thienothiophene structure, which will not be listed one by one in this article.

[0081] In some embodiments, a is selected from 0, 1, 2 and 3; 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 a preferred range, thereby making the viscosity and solubility of the compound appropriate, 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, take 5.2g (14.50mmol) (referred to as "A-1-A"), 840mg (0.7mmol) tetrakis (triphenylphosphine) palladium (referred to as Pd (PPh3) 4), 6.14g (29mmol) potassium phosphate (referred to as K3PO4), add to a three-necked flask (250mL), keep the system closed, and replace the gas in the three-necked flask with argon. Then add 13mL of water and 52mL of toluene to react. After the reaction temperature is raised to 75°C, 2.85g (17.4mmol) of a substance dissolved in dimethyl sulfoxide (referred to as DMSO) (referred to as "A-1-B") is slowly added using an automatic sampler and reacted for 3 hours. After the reaction is completed, cool to room temperature, filter on silica gel, wash with water twice, and extract with ethyl acetate in sequence 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 subjected to column chromatography using n-hexane as an eluent to separate and purify 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 (Pd (dppf) Cl2 for short), 144mg (0.76mmol) copper iodide (Cu I for short) 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 in 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 spin-dried, and then purified by column chromatography using n-hexane as an eluent to obtain a light yellow solid, which was further slurried with methanol to obtain 4.45 g of substance "A-1" with a GC purity of 99.98%, and 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]

[0090] In summary, the structural formula of compound A provided in Example 1 of the present application is:

[0091]

[0092] Example 2

[0093] (1) Preparation of 3-methyl-2-{[4-(4-pentylphenyl)phenyl]ethynyl}thieno[3,2-b]thiophene, referred to as "A-2-C".

[0094] Specifically, in a three-necked flask (500 mL), add the raw material "A-2-B" (9.1 g, 36.9 mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (Pd(dppf)Cl2 for short) (808 mg, 1.1 mmol), copper iodide (Cu I for short) (421 mg, 2.2 mmol). Keep the system closed and replace the gas in the three-necked flask with argon. Add the raw material "A-2-A" (8.6 g, 36.9 mmol), diisopropylamine (20 mL), and DMSO (172 mL). After the reaction is heated to 120°C, continue the reaction for 3 hours. After the reaction is completed, cool to room temperature, filter with silica gel, wash with water twice, and extract with ethyl acetate in sequence 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 subjected to column chromatography using n-hexane as an eluent to separate and purify a light yellow solid, which was further slurried with methanol to obtain 12.16 g of substance "A-2-C" with a GC purity of 99.9%.

[0095] (2) Preparation of 3-methyl-2-{[4-(4-pentylphenyl)phenyl]ethynyl}-5-propylthieno[3,2-b]thiophene, referred to as "A-2".

[0096] Specifically, in a three-necked flask (500 mL), add the raw material "A-2-C" (8 g, 20 mmol), keep the system airtight, and replace the gas in the three-necked flask with argon. Add tetrahydrofuran (THF) (240 mL), stir to dissolve, put into a -78°C low-temperature reactor and 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), heat to room temperature, and react for 1 h. The reaction was quenched with a saturated aqueous solution of ammonium chloride, washed twice with water, extracted with ethyl acetate to obtain an organic phase, which was washed twice with a saturated aqueous solution of ammonium chloride and twice with a saturated aqueous solution of sodium chloride, dried over anhydrous sodium sulfate, filtered and spin-dried, and then column chromatography was performed using n-hexane as an eluent to separate and purify a white solid, which was further recrystallized and slurried multiple times with a mixed solution of ethyl acetate / methanol to obtain 6.8 g of substance "A-2" with a GC purity of 99.9% and GC-MS (EI) m / z=442.

[0097] The reaction process of (1) and (2) in the above embodiment 2 is shown in the following formula:

[0098]

[0099] In summary, the structural formula of compound A provided in Example 2 of the present application is:

[0100]

[0101] Example 3

[0102] (1) Preparation of 2-{[4-(4-butylphenyl)phenyl]ethynyl}-3-methylthieno[3,2-b]thiophene, referred to as "A-3-C".

[0103] Specifically, in a three-necked flask (500 mL), add the raw material "A-3-B" (7.2 g, 31.1 mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (Pd(dppf)Cl2 for short) (452 ​​mg, 0.6 mmol), copper iodide (Cu I for short) (235 mg, 1.2 mmol), keep the system airtight, and replace the gas in the three-necked flask with argon. Add the raw material "A-3-A" (7.2 g, 31.1 mmol), diisopropylamine (18 mL), and DMSO (150 mL). After the reaction is heated to 120°C, continue the reaction for 3 hours. After the reaction is completed, cool to room temperature, filter on silica gel, wash twice with water, and extract with ethyl acetate in sequence 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 subjected to column chromatography using n-hexane as an eluent to separate and purify a white solid, which was further slurried with methanol to obtain 9.93 g of substance "A-3-C" with a GC purity of 99.9%.

[0104] (2) Preparation of 3-methyl-2-{[4-(4-pentylphenyl)phenyl]ethynyl}-5-propylthieno[3,2-b]thiophene, referred to as "A-3"

[0105] Specifically, in a three-necked flask (500 mL), add the raw material "A-3-C" (8 g, 20.7 mmol), keep the system airtight, and replace the gas in the three-necked flask with argon. Add tetrahydrofuran (abbreviated as THF) (160 mL) and stir to dissolve, put it into a -78°C low-temperature reactor and stir for 0.5 h, add lithium diisopropylamide (abbreviated as LDA) (21.7 mL, 43.4 mmol) dropwise, and react for 3 h. Add "A-3-D" (7.4 g, 43.4 mmol), heat to room temperature, and react for 1 h. The reaction was quenched with a saturated aqueous solution of ammonium chloride, washed twice with water, extracted with ethyl acetate to obtain an organic phase, which was washed twice with a saturated aqueous solution of ammonium chloride and twice with a saturated aqueous solution of sodium chloride, dried over anhydrous sodium sulfate, filtered and spin-dried, and then column chromatography was performed using n-hexane as an eluent to separate and purify a white solid, which was further recrystallized and slurried multiple times with a mixed solution of ethyl acetate / methanol to obtain 4.14 g of "A-3" with a GC purity of 99.9% and GC-MS (EI) m / z=428.

[0106] The reaction process of (1) and (2) in the above Example 3 is shown in the following formula:

[0107]

[0108] In summary, the structural formula of compound A provided in Example 3 of the present application is:

[0109]

[0110] Example 4

[0111] (1) Preparation of 2-bromo-3-methyl-5-(4-pentylphenyl)thieno[3,2-b]thiophene, referred to as "A-4-C".

[0112] Specifically, in a three-necked flask (250 mL), add the raw material "A-4-A" (5.5 g, 15.318 mmol), tetrakis(triphenylphosphine)palladium (Pd(PPh3)4 for short) (885 mg, 0.76 mmol), potassium phosphate (K3PO4 for short) (6.5 g, 30.6 mmol), and replace the gas in the three-necked flask with argon. Add water (25 mL) and toluene (100 mL). After the reaction is heated to 75°C, use an automatic sampler to slowly add "A-4-B" (3.53 g, 18.38 mmol) dissolved in dimethyl sulfoxide (DMSO for short), and react for 3 hours. After the reaction is completed, cool to room temperature, filter on silica gel, wash twice with water, and extract with ethyl acetate in sequence 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 subjected to column chromatography using n-hexane as an eluent to separate and purify 5.3 g of a white solid substance "A-4-C" with a GC purity of 99%.

[0113] (2) Preparation of 3-methyl-5-(4-pentylphenyl)-2-[(4-propylphenyl)ethynyl]thieno[3,2-b]thiophene, referred to as "A-4".

[0114] Specifically, in a three-necked flask (500 mL), add the raw material "A-4-C" (5.3 g, 13.99 mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (Pd(dppf)Cl2 for short) (306 mg, 0.419 mmol), copper iodide (CuI for short) (159 mg, 0.839 mmol). Keep the system closed and replace the gas in the three-necked flask with argon. Add the raw material "A-4-D" (2.42 g, 16.79 mmol), diisopropylamine (20 mL), and DMSO (150 mL). After the reaction is heated to 120°C, continue the reaction for 3 hours. After the reaction is completed, cool to room temperature, filter on silica gel, wash twice with water, and extract with ethyl acetate in sequence 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, dried over anhydrous sodium sulfate, filtered and spin-dried, and then subjected to column chromatography using n-hexane as an eluent to separate and purify a light yellow solid, which 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.

[0115] The reaction process of (1) and (2) in the above Example 4 is shown in the following formula:

[0116]

[0117] In summary, the structural formula of compound A provided in Example 4 of the present application is:

[0118]

[0119] Example 5

[0120] (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".

[0121] Specifically, in a three-necked flask (250 mL), add raw material "A-5-A" (5.5 g, 15.318 mmol), tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) (885 mg, 0.76 mmol), potassium phosphate (K3PO4) (6.5 g, 30.6 mmol), and replace the gas in the three-necked flask with argon. Add water (25 mL) and toluene (100 mL). The reaction temperature is raised to 75°C, and "A-5-B" (3.23 g, 18.38 mmol) dissolved in dimethyl sulfoxide (DMSO) is slowly added using an automatic sampler, and the reaction is carried out for 3 hours. After the reaction is completed, cool to room temperature, filter on 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 spin-dried, and then subjected to column chromatography using n-hexane as an eluent to separate and purify 2.7 g of a yellow solid substance "A-5-C" with a GC purity of 96.5%.

[0122] (2) Preparation of 3-methyl-2-[(4-pentylphenyl)ethynyl]-5-(3,4,5-trifluorophenyl)thieno[3,2-b]thiophene, referred to as "A-5".

[0123] Specifically, in a three-necked flask (250 mL), add the raw material "A-5-C" (2.7 g, 7.43 mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (Pd(dppf)Cl2 for short) (163 mg, 0.223 mmol), copper iodide (Cu I for short) (84.9 mg, 0.446 mmol). Keep the system closed and replace the gas in the three-necked flask with argon. Add the raw material "A-5-D" (1.66 g, 9.66 mmol), diisopropylamine (20 mL), and DMSO (80 mL). The reaction temperature is raised to 120°C and the reaction is allowed to react for 3 hours. After the reaction is completed, cool to room temperature, filter on silica gel, wash twice with water, and extract with ethyl acetate in sequence 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, dried over anhydrous sodium sulfate, filtered and spin-dried, and then subjected to column chromatography using n-hexane as an eluent to separate and purify a light yellow solid, which 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.

[0124] The reaction process of (1) and (2) in the above Example 5 is shown in the following formula:

[0125]

[0126] In summary, the structural formula of compound A provided in Example 5 of the present application is:

[0127]

[0128] Example 6

[0129] (1) Preparation of 3-methyl-2-{[4-(4-propylphenyl)phenyl]ethynyl}thieno[3,2-b]thiophene, referred to as "A-6-C"

[0130] Specifically, raw material "A-6-B" (15.6g, 70.8mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (Pd(dppf)Cl2 for short) (1.0g, 1.4mmol), copper iodide (CuI for short) (540mg, 2.8mmol) were added to a three-necked flask (500mL). The system was kept closed and the gas in the three-necked flask was replaced with argon. Raw material "A-6-A" (16.5g, 70.8mmol), diisopropylamine (40mL), and DMSO (330mL) were added. After the reaction was heated 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 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 spin-dried, and then subjected to column chromatography using n-hexane as an eluent to separate and purify a light yellow solid, which was further slurried with methanol to obtain 22.35 g of substance "A-6-C" with a GC purity of 99.6%.

[0131] (2) Preparation of 3-methyl-5-propyl-2-{[4-(4-propylphenyl)phenyl]ethynyl}thieno[3,2-b]thiophene, referred to as "A-6".

[0132] Specifically, add the raw material "A-6-C" (11 g, 29.5 mmol) to a three-necked flask (500 mL), keep the system airtight, and replace the gas in the three-necked flask with argon. Add tetrahydrofuran (THF) (220 mL) and stir to dissolve, put it into a -78°C low-temperature reactor and stir for 0.5 h, 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), heat to room temperature, and react for 1 h. The reaction was quenched with a saturated aqueous solution of ammonium chloride, washed twice with water, extracted with ethyl acetate to obtain an organic phase, which was washed twice with a saturated aqueous solution of ammonium chloride and twice with a saturated aqueous solution of sodium chloride, dried over anhydrous sodium sulfate, filtered and spin-dried, and then column chromatography was performed using n-hexane as an eluent to separate and purify a white solid, which was further recrystallized and slurried multiple times with a mixed solution of ethyl acetate / methanol to obtain 6.26 g of "A-6" substance with a GC purity of 99.9% and GC-MS (EI) m / z=414.

[0133] The reaction process of (1) and (2) in the above Example 6 is shown in the following formula:

[0134]

[0135] In summary, the structural formula of compound A provided in Example 6 of the present application is:

[0136]

[0137] Example 7

[0138] (1) Preparation of 3-methyl-2-{[4-(4-propylphenyl)phenyl]ethynyl}thieno[3,2-b]thiophene, referred to as "A-7-C".

[0139] Specifically, the raw material "A-7-B" (15.6g, 70.8mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (Pd(dppf)Cl2 for short) (1.0g, 1.4mmol), copper iodide (CuI for short) (540mg, 2.8mmol) were added to a three-necked flask (500mL). The system was kept closed and the gas in the three-necked flask was replaced with argon. The raw material "A-7-A" (16.5g, 70.8mmol), diisopropylamine (40mL), and DMSO (330mL) were added. After the reaction was heated 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 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 spin-dried, and then subjected to column chromatography using n-hexane as an eluent to separate and purify a light yellow solid, which was further slurried with methanol to obtain 22.35 g of substance "A-7-C" with a GC purity of 99.6%.

[0140] (2) Preparation of 5-ethyl-3-methyl-2-{[4-(4-propylphenyl)phenyl]ethynyl}thieno[3,2-b]thiophene, referred to as "A-7".

[0141] Specifically, add the raw material "A-7-C" (11 g, 29.5 mmol) to a three-necked flask (500 mL), keep the system airtight, and replace the gas in the three-necked flask with argon. Add tetrahydrofuran (THF) (220 mL) and stir to dissolve, put it into a -78°C low-temperature reactor and stir for 0.5 h, 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, heat to room temperature, and react for 1 h. The reaction was quenched with a saturated aqueous solution of ammonium chloride, washed twice with water, extracted with ethyl acetate to obtain an organic phase, which was washed twice with a saturated aqueous solution of ammonium chloride and twice with a saturated aqueous solution of sodium chloride, dried over anhydrous sodium sulfate, filtered and spin-dried, and then column chromatography was performed using n-hexane as an eluent to separate and purify a brown solid, which was further recrystallized and slurried multiple times with a mixed solution of ethyl acetate / methanol to obtain 5.97 g of "A-7" substance with a GC purity of 99.9% and GC-MS (EI) m / z=400.

[0142] The reaction process of (1) and (2) in the above Example 7 is shown in the following formula:

[0143]

[0144] In summary, the structural formula of compound A provided in Example 7 of the present application is:

[0145]

[0146] Example 8

[0147] (1) Preparation of 2-bromo-5-(4-butylphenyl)-3-methylthieno[3,2-b]thiophene, referred to as "A-8-C".

[0148] Specifically, the raw material "A-8-A" (4.9 g, 13.6 mmol), tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) (789 mg, 0.7 mmol), potassium phosphate (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 (DMSO) was slowly added using an automatic sampler, and the reaction was allowed to proceed 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 subjected to column chromatography using n-hexane as an eluent to separate and purify 4.15 g of a white solid substance "A-8-C" with a GC purity of 98.5%.

[0149] (2) Preparation of 5-(4-butylphenyl)-3-methyl-2-[(4-propylphenyl)ethynyl]thieno[3,2-b]thiophene, referred to as "A-8".

[0150] Specifically, raw material "A-8-C" (4.15g, 11.4mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (Pd(dppf)Cl2 for short) (249mg, 0.3mmol), copper iodide (CuI for short) (131mg, 0.7mmol) 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. Raw material "A-8-D" (1.97g, 13.6mmol), diisopropylamine (5mL), and DMSO (100mL) were added. After the reaction was heated 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 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 a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spin-dried, and then subjected to column chromatography using n-hexane as an eluent to separate and purify a light yellow solid, which was further slurried with methanol to obtain 3.92 g of "A-8" substance with a GC purity of 99.9% and GC-MS (EI) m / z=428.

[0151] The reaction process of (1) and (2) in the above Example 8 is shown in the following formula:

[0152]

[0153] In summary, the structural formula of compound A provided in Example 8 of the present application is:

[0154]

[0155] Example 9

[0156] (1) Preparation of 2-bromo-3-methyl-5-(4-propylphenyl)thieno[3,2-b]thiophene, referred to as "A-9-C".

[0157] Specifically, raw materials "A-9-A" (14 g, 38.99 mmol), tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) (2.25 g, 1.94 mmol), potassium phosphate (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 (DMSO) was slowly added using an automatic sampler, and the reaction was allowed to proceed 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 subjected to column chromatography using n-hexane as an eluent to separate and purify to obtain 11.89 g of a white solid "A-9-C" with a GC purity of 99.2%.

[0158] (2) Preparation of 3-methyl-5-(4-propylphenyl)-2-[(4-propylphenyl)ethynyl]thieno[3,2-b]thiophene, referred to as "A-9".

[0159] Specifically, in a three-necked flask (250 mL), add the raw material "A-9-C" (5.9 g, 16.79 mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (Pd(dppf)Cl2 for short) (368 mg, 0.503 mmol), copper iodide (CuI for short) (191 mg, 1.007 mmol). Keep the system closed and replace the gas in the three-necked flask with argon. Add the raw material "A-9-D" (3.14 g, 21.83 mmol), diisopropylamine (20 mL), and DMSO (160 mL). The reaction temperature was raised to 120 ° C and the reaction was allowed to react 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 spin-dried, and then purified by column chromatography using n-hexane as an eluent to obtain a yellow solid, which was further slurried with methanol to obtain 6.36 g of "A-9-C" substance with a GC purity of 99.9% and GC-MS (EI) m / z=414.

[0160] The reaction process of (1) and (2) in the above Example 9 is shown in the following formula:

[0161]

[0162] In summary, the structural formula of compound A provided in Example 9 of the present application is:

[0163]

[0164] Example 10

[0165] (1) 2-Bromo-3-methyl-5-(4-propylphenyl)thieno[3,2-b]thiophene, referred to as "A-10-C".

[0166] Specifically, the raw material "A-10-A" (14 g, 38.99 mmol), tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) (2.25 g, 1.94 mmol), potassium phosphate (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 (DMSO) was slowly added using an automatic sampler, and the reaction was allowed to proceed 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 subjected to column chromatography using n-hexane as an eluent to separate and purify to obtain 11.89 g of a white solid "A-10-C" with a GC purity of 99.2%.

[0167] (2) Preparation of 2-[(4-ethylphenyl)ethynyl]-3-methyl-5-(4-propylphenyl)thieno[3,2-b]thiophene, referred to as "A-10".

[0168] Specifically, the raw material "A-10-C" (5.9 g, 16.79 mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (Pd(dppf)Cl2 for short) (368 mg, 0.503 mmol), and copper iodide (CuI for short) (191 mg, 1.007 mmol) were added to a 500 mL three-necked flask. The system was kept closed 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 was heated 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 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 a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered and spin-dried, and then subjected to column chromatography using n-hexane as an eluent to separate and purify a yellow solid, which was further slurried with methanol to obtain 5.8 g of "A-10" substance with a GC purity of 99.9% and GC-MS (EI) m / z=400.

[0169] The reaction process of (1) and (2) in the above Example 10 is shown in the following formula:

[0170]

[0171] In summary, the structural formula of compound A provided in Example 10 of the present application is:

[0172]

[0173] The 10 compounds A provided in the above embodiments are only examples and do not constitute a limitation on the embodiments of the present application. The compounds A provided in the embodiments of the present application can be any structure that conforms to the general formula shown in formula (I), and are not listed here one by one.

[0174] 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.

[0175] Δn(589nm, 25℃)=n e (589nm, 25℃)-n o (589nm, 25℃). e (589nm, 25℃), n o (589 nm, 25°C) were measured using ATAGO-DR-M4 Abbe refractometer.

[0176] Δε(1kHz, 25℃)=ε ∥ (1kHz, 25℃)-ε ⊥ (1kHz, 25℃). ∥ Represents the dielectric constant in the direction parallel to the liquid crystal, ε ⊥ Represents the dielectric constant of the liquid crystal in the vertical direction, ε ∥ (1kHz, 25℃) and ε ⊥ (1kHz, 25℃) are all measured using ALCT-IV1 liquid crystal comprehensive parameter tester.

[0177] CP, clearing point of liquid crystal; measured using a Mettler DSC3 differential scanning calorimeter in a nitrogen atmosphere at a heating rate of 10°C / min, in °C, expressed as T NI (℃).

[0178] The test results are shown in Table 1.

[0179] Table 1

[0180] Compound A Δn Δε <![CDATA[T NI (℃)]]> A-1 0.48 3.6 256 A-2 0.45 3.1 250 A-3 0.45 3.1 254 A-5 0.40 14 165

[0181] The compound A provided in the comparative example of the present application may have the following structure B-1.

[0182]

[0183] The compound with the structural formula A-1 was used as a liquid crystal monomer and dissolved in the mother liquid crystal at a mass percentage of 10% to obtain a liquid crystal composition sample 1. The compound with the structural formula B-1 provided in the comparative example was used as a liquid crystal monomer and dissolved in the mother liquid crystal at a mass percentage of 10% to obtain a liquid crystal composition sample 2. The mother liquid crystal was prepared by mixing monomers such as phenylcyclohexane, biphenylcyclohexane, and terphenyl.

[0184] The voltage holding rate of the liquid crystal composition sample 1 and the liquid crystal composition sample 2 was tested by the following method. The test results are shown in Table 2.

[0185] First, the liquid crystal composition sample 1 was poured into two TN type liquid crystal cells with a cell thickness of 7 μm and sealed to obtain liquid crystal cell sample 1 and liquid crystal cell sample 2. The liquid crystal composition sample 2 was poured into two TN type liquid crystal cells with a cell thickness of 7 μm and sealed to obtain liquid crystal cell sample 3 and liquid crystal cell sample 4.

[0186] Then, the liquid crystal box sample 1 is placed in a UV test box, a 365nm light source is used, and a set irradiation dose is accumulated to perform UV aging treatment on the liquid crystal composition sample 1; the liquid crystal box sample 2 is placed in a high-temperature incubator that can adjust high and low temperatures, the temperature is set to 100°C, and the sample is taken out after a preset baking time, and the liquid crystal composition sample 1 is subjected to high-temperature aging treatment. The liquid crystal box sample 3 is placed in a UV test box, a 365nm light source is used, and a set irradiation dose is accumulated to perform UV aging treatment on the liquid crystal composition sample 2; the liquid crystal box sample 4 is placed in a high-temperature incubator that can adjust high and low temperatures, the temperature is set to 100°C, and the sample is taken out after a preset baking time, and the liquid crystal composition sample 2 is subjected to high-temperature aging treatment.

[0187] Finally, before and after aging, the voltage holding rate (V HR ).

[0188] Table 2

[0189]

[0190] It can be seen from the above table that compared with the compound structure B-1 given in the comparative example, the voltage holding rate of the compound structure A-1 provided in the embodiment of the present application is reduced to a smaller extent, so the performance of the device containing the liquid crystal compound material of the present invention will also be more stable.

[0191] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope 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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