Ester derivate, liquid crystal composition and liquid crystal display element

Abstract: A novel liquid crystalline compound having a large dielectric anisotropy value, a small change in the threshold voltage depending upon temperatures, and an improved solubility in other liquid crystal materials at low temperatures, and a liquid crystal composition containing the compound are provided, which liquid crystalline compound is expressed by the formula (1) wherein R is H or an alkyl group of 1 to 10C; ℓ is an integer of 1 to 9; m, n and o are each independently 0 or 1; A 1 , A 2 and A 3 are each independently trans-1,4-cyclohexylene group, 1,4-pheylene group, one or more H atoms on the ring of which group may be replaced by F, or the like group; Z 1 , Z 2 and Z 3 are each independently -COO-, etc., but at least one member of them is -COO-; X is CF 3 ,etc.; and Y 1 and Y 2 are each independently H or F.

Description: This invention relates to a liquid crystalline compound and a liquid crystal composition, and more particularly, it relates to a novel ester compound having a 3,5-difluoro-4-substituted phenyl group, a liquid crystal composition containing the compound, and a liquid crystal composition composed by using the liquid crystal composition. Display elements using liquid crystalline compounds have been broadly utilized for watch, electric calculator or word processor. These display elements are those utilizing the optical anisotropy, or dielectric anisotropy, of liquid crystalline compounds. Liquid crystal phases include nematic liquid crystal phase, smectic liquid crystal phase and cholesteric liquid crystal phase, and among these, materials utilizing nematic liquid crystal phase have been most broadly used. Further, display modes include dynamic scattering (DS) mode, deformation of vertical aligned phase (DAP) mode, guest-host (GH) mode, twisted nematic (TN) mode, super-twisted nematic (STN) mode or thin-film transistor (TFT) mode. Liquid crystalline compounds used in these display modes are necessary to exhibit liquid crystal phases within a broad temperature range around room temperature, has a sufficient stability under conditions under which display elements are used; and have characteristics sufficient for driving display elements, but at present, a single liquid crystalline compound satisfying these conditions has not yet been found. Thus, it is an actual state that liquid crystal compositions provided with required characteristics have been prepared by blending liquid crystalline compounds of several kinds to several tens kinds and if necessary, further non-liquid crystalline compounds. It is required for these liquid crystal compositions to be stable to light, heat and air which are usually present under conditions wherein display elements are used, and further to be stable to electric field or electromagnetic irradiation, and still further to be chemically stable to compounds to be blended. Further, it is required for liquid crystal compositions that the values of various physical properties such as optical anisotropy value (Δn) or dielectric anisotropy value (Δε) are suitable, depending upon the display mode and the shape of the display element. Further, the respective components in the liquid crystal compositions are important to have a good compatibility with each other. Among these requirements, there has been increasing a requirement for further reduction in the threshold voltage greatly contributing to a high speed response necessary for making a large picture surface of liquid crystal display elements. A liquid crystalline compound having a large Δε value is necessary therefor. (E. Jakeman et al, Phys. Lett., 39A. 69 (1972)). Further, in order to make a high picture surface quality possible, a liquid crystalline compound having a small change in the threshold voltage depending upon temperatures is needed. In order to achieve these objects, compounds of the formulas (a) and (b) are respectively disclosed in Japanese patent application Hyo No. Hei 3-503637 and Japanese patent application laid-open No. Hei 4-279560. Further, compounds disclosed in Japanese patent application laid-open No. Sho 55-40660, Japanese patent application Hyo No. Hei 2-501311, and Japanese patent application Hyo No. Hei 3-500413 are known. However, these compounds have problems that change in the threshold voltage depending upon temperatures can not be yet regarded as being sufficiently small and further the solubility thereof in liquid crystal compositions at low temperatures is insufficient. GB-A-2 266 714 discloses alkoxymethylene compounds comprising a 3,4,5-trifluoro phenyl terminal or a 3,5-difluoro-4-cyanophenyl terminal, and their use in liquid crystalline compositions. GB-A-2 232 156 describes phenyl esters containing a 3,5-difluoro-4-cyano terminal. A preferred compound is R-Cyc-C 2 H 4 -Phe-COO-(3,5-F,F-4-CN)-Phe, wherein R is C 1-15 alkyl, Cyc is 1,4-trans-cyclohexylene and Phe is 1,4-phenylene. Chemical Abstracts, 118: 91088d and 118: 113347s describe the preparation of cyanodifluorophenyl esters which lower the threshold voltage. The object of the present invention is to provide an ester compound which has overcome the above drawbacks of the prior art, and has a particularly large Δε, a small change in the driving voltage depending upon temperatures, and an improved solubility in other liquid crystal compositions at low temperatures; a liquid crystal composition containing the above compound; and a liquid crystal display element composed using the liquid crystal composition. The present invention is directed to a liquid crystalline compound as defined in claim 1. This invention is also directed to a liquid crystal composition as defined in the claims 2 to 5 and to a liquid crystal display element as described in claim 6. The liquid crystalline compound of the present invention expressed by the formula (1) has a large Δε, a small change in the threshold voltage depending upon temperatures and a good solubility in other liquid crystal compositions even at low temperatures. Further, these liquid crystalline compounds are physically and chemically sufficiently stable under conditions where display elements are usually used, and further, when the six-membered ring, substituent and/or bonding group, among the molecule-constituting elements are suitably selected, it is possible to derive them into those having desired physical properties. Thus, when the compound of the present invention is used as a component of liquid crystal composition, it is possible to provide a novel liquid crystal composition having preferred characteristics. The compound of the present invention expressed by the formula (1) is classified into those expressed by the following formulas (la) to (1ℓ): Compound having 2 six-membered rings: R 9 - A 1 - COO - Q Compounds having 3 six-membered rings: R 9 - A 1 - A 2 - COO - Q R 9 - A 1 - (CH 2 ) 2 - A 2 - COO - Q R 9 - A 1 - COO - A 2 - COO - Q Compounds having 4 six-membered rings: R 9 - A 1 - COO - A 2 - A 3 - Q R 9 - A 1 - A 2 - COO - A 3 - Q R 9 - A 1 - A 2 - A 3 - COO - Q R 9 - A 1 - COO - A 2 - COO - A 3 - Q R 9 - A 1 - (CH 2 ) 2 - A 2 - COO - A 3 - Q R 9 - A 1 - (CH 2 ) 2 - A 2 - A 3 - COO - Q R 9 - A 1 - A 2 - (CH 2 ) 2 - A 3 - COO - Q In these formulas, R 9 is a group expressed below: Q is a group expressed below: The compound expressed by the formula (1a) preferably has the following formula(1ab): R 9 - P h e - COO - Q In the above formulas, Cyc represents trans-1,4-cyclohexylene group; Phe represents 1,4-phenylene group; one or more hydrogen atoms of the-Phe may be replaced by F; A 1 , A 2 and A 3 are selected from the group consisting of Cyc, Phe, Pyr, Pyd and Dio, and preferably two or more Pyr, Pyd, Dio are not contained in the molecule. Compounds expressed by the formula (1b) are developed into those expressed by the following formulas (1bb) to (1bh): R 9 - Cyc - Phe - COO - Q R 9 - Phe - Cyc - COO - Q R 9 - Phe - Phe - COO - Q R 9 - Pyr - Phe - COO - Q R 9 - Pyr - Cyc - COO - Q R 9 - Pyd - Phe - COO - Q R 9 - Pyd - Cyc - COO - Q R 9 - Dio - Phe - COO - Q Among these compounds, those expressed by the formulas (1bb) to (1be), (1bg) and (1bi) are particularly preferred. The compounds expressed by the formula (1d) are further developed into those expressed by the following formulas (1db) to (1dj) : R 9 - Cyc - (CH 2 ) 2 - Phe - COO - Q R 9 - Phe - (CH 2 ) 2 - Cyc - COO - Q R 9 - Phe - (CH 2 ) 2 - Phe - COO - Q R 9 - Phe - (CH 2 ) 2 - Pyr - COO - Q R 9 - Pyr - (CH 2 ) 2 - Phe - COO - Q R 9 - Pyd - (CH 2 ) 2 - Phe - COO - Q R 9 - Dio - (CH 2 ) 2 - Phe - COO - Q Among these compounds, compounds expressed by the formulas (1db) to (1dd) are particularly preferred. The compounds expressed by the formula (1e) are further developed into compounds expressed by the following formulas (1eb) to (1ej): R 9 - Cyc - COO - Phe - COO - Q R 9 - Phe - COO - Cyc - COO - Q R 9 - Phe - COO - Phe - COO - Q R 9 - Phe - COO - Pyr - COO - Q R 9 - Pyr - COO - Phe - COO - Q R 9 - Pyr - COO - Cyc - COO - Q R 9 - Pyd - COO - Phe - COO - Q R 9 - Dio - COO - Phe - COO - Q Among these compounds, compounds expressed by the formulas (1eb) to (1ed) are particularly preferred. The compounds expressed by the formula (lf) are further developed into compounds expressed by the following formulas (1fb) to (1fh) : R 9 - Cyc - COO - Cyc - Phe - Q R 9 - Cyc - COO - Phe - Phe - Q R 9 - Cyc - COO - Phe - Cyc - Q R 9 - Phe - COO - Cyc - Cyc - Q R 9 - Phe - COO - Cyc - Phe - Q R 9 - Phe - COO - Phe - Cyc - Q R 9 - Phe - COO - Phe - Phe - Q Among these compounds, compounds expressed by the formulas (1fb), (1fc), (1ff) and (1fh) are particularly preferred. The compounds expressed by the formula (lg) are further developed into compounds expressed by the following formulas (1gb) to (1gh) : R 9 - Cyc - Cyc - COO - Phe - Q R 9 - Cyc - Phe - COO - Cyc - Q R 9 - Cyc - Phe - COO - Phe - Q R 9 - Phe - Cyc - COO - Cyc - Q R 9 - Phe - Cyc - COO - Phe - Q R 9 - Phe - Phe - COO - Cyc - Q R 9 - Phe - Phe - COO - Phe - Q Among these compounds, those expressed by the formulas (1gb), (1gc) and (1gd) are particularly preferred. The compounds expressed by the formula (lh) are further developed into compounds expressed by the following formulas (1hb) to (1hh): R 9 - Cyc - Cyc - Phe - COO - Q R 9 - Cyc - Phe - Phe - COO - Q R 9 - Cyc - Phe - Cyc - COO - Q R 9 - Phe - Cyc - Cyc - COO - Q R 9 - Phe - Phe - Cyc - COO - Q R 9 - Phe - Cyc - Phe - COO - Q R 9 - Phe - Phe - Phe - COO - Q In all of the above mentioned compounds, R 9 represents an alkoxyalkyl group of 2 to 19 carbon atoms, and particularly preferred groups among them are methoxymethyl, methoxyethyl, methoxypropyl, methoxybutyl, methoxypentyl, methoxynonyl, ethoxymethyl, ethoxyethyl, ethoxypropyl, ethoxybutyl, propoxymethyl, propoxyethyl, propoxypropyl, butoxymethyl, butoxyethyl, pentyloxymethyl, hexyloxymethyl, heptyloxymethyl and decyloxymethyl. As described above, compounds expressed by the formulas, (1ab), (1bb), (1bc), (1bd), (1be), (1bg), (1bi), (1cb), (1ce), (1cf), (1db), (1dc), (1dd), (1eb), (1ec), (1ed), (1fb), (1fc), (1ff), (1fh), (1gb), (1gc), (1gd) and (1hb) can be said to be particularly preferred, but among them as more preferred compounds, compounds expressed by the following formulas (1-1) to (1-24) can be mentioned: wherein is 3,5 difluoro-4-cyanophenylene. The liquid crystalline compound of the present invention expressed by the formula (1) can be prepared according to known, general organic synthesis process. For example, it can be conveniently prepared according to the following process: Namely, it is possible to prepare the compound of the formula (1), by esterification such as dehydration condensation. In more details, a carboxylic acid derivative ( 1 ) is converted into an acid halide ( 2 ), by means of a halogenating reagent such as thionyl chloride etc., in a solvent such as toluene, benzene, etc. or in the absence of solvent, followed by reacting ( 2 ) with a phenol derivative ( 3 ) in a solvent such as toluene, benzene, etc., to obtain the objective compound example ( 4 ). The reactions in a series is preferably carried out at a temperature between room temperature and the boiling point of solvent, and further in the presence of a base such as pyridine, triethylamine, dimethylaniline, tetramethyl urea, etc. (E.J. Corey et al, Journal of Organic Chemistry, 38, 3223 (1973), C. Raha, Organic Synthesis, IV, 263 (1963), B. Iselin et al, Helvetica Chimica Acta, 40, 373 (1957), M.S. Newman et al, Tetrahedron Letters, 3267 (1967)). Alternatively, when a carboxylic acid derivative ( 1 ) is reacted with a phenol derivative ( 3 ), in a solvent such as dichloromethane, chloroform, etc., and in the presence of dicyclohexylcarbodiimide (hereinafter abbreviated to DCC) and dimethylaminopyrimidine (hereinafter abbreviated to DMAP), it is also possible to obtain the objective compound exmaple ( 4 ) (B. Neises et al, Organic Synthesis, 63, 183 (1985)). The carboxylic acid derivative ( 1 ) as one of the raw materials can be prepared for example according to the following process: Namely, when compound ( 5 ) is reacted with a sodium alkoxide, to obtain a compound ( 6 ), followed by hydrolysis in the presence of a base such as NaOH, KOH, etc., it is possible to obtain a carboxylic acid derivative example ( 7 ). Further, when a Grignard reagent ( 8 ), of a dihalogenobenzene is prepared, followed by reacting it with ethylene oxide, to obtain an alcohol (9) and then an ether ( 10 ), preparing a Grignard reagent of the ether and reacting it with CO 2 , it is possible to obtain a carboxylic acid derivative example ( 11 ). In the case of the alcohol ( 9 ), compounds having an ℓ of 3 or more can be obtained by reacting with the corresponding ring-form ether in place of ethylene oxide. Alternatively, (9) can be easily obtained by carrying out carbon number-increasing reaction according to a known, general organic synthesis process, for example, to prepare the corresponding derivative of carboxylic acid, aldehyde, ester, etc., followed by reducing the derivative with a reducing agent such as sodium boron hydride (SBH), borane, lithium aluminum hydride (LAH), sodium bis(2-methoxyethoxy)aluminum hydride (SBMEA, Red-Aℓ) or the like. Alternatively, it is possible to obtain the carboxylic acid derivative example ( 16 ), by reducing aldehyde ( 12 ) with a reducing agent such as SBH, LAH, diisobutylaluminum hydride (DIBAL) or the like, to obtain alcohol ( 13 ), followed by reacting it with a halogenizing agent such as thionyl chloride or the like, to obtain halide ( 14 ), reacting the halide with a sodium alkoxide to obtain ether ( 15 ) and reacting it with oxalyl chloride, to obtain an acid chloride; and hydrolyzing it to obtain a carboxylic derivative example (16). Among the raw materials, the phenol derivative can be prepared for example according to the following processes: Namely, a substituted phenol ( 17 ), is converted into an ether substance ( 18 ) by means of tetrahydropyranyl group or the like, followed by reacting it with an organolithium reagent such as butyllithium or the like and iodine, to obtain an iodine substance ( 19 ), cyanogenating it, and deprotecting, to obtain a phenol derivative example ( 20 ). Either of the thus obtained liquid crystalline compound of the present invention exhibit a large Δε, and have a small change in the threshold voltage depending on temperatures, are easily blended with various liquid crystal materials, and have a good solubility therewith even at low temperatures; hence the compound is far superior as a constituting component of nematic liquid crystal compositions. The compound of the present invention is usable as a constituting component in either of liquid crystal compositions of TFT mode, TN mode and STN mode which at present constituted main current, and these compounds are particularly preferred for STN. When the compound of the present invention is used as a constituting component of nematic liquid crystal compositions, compounds having a structure of two rings exhibit a relatively low liquid crystal temperature range and a low viscosity, and compounds having a structure of 3 or 4 rings exhibit a broad liquid crystal temperature range and a relatively high viscosity; hence when these compounds are adequately selected, it is possible to obtain liquid crystal compositions having desired physical properties. Further, the compounds among those of the present invention having a 3,5-difluoro-4-substituted phenyl group exhibit a large Δε, and when hydrogen atoms in other ring structure are replaced by fluorine atoms, it is possible to impart a further large Δε. The liquid crystal composition provided by the present invention may be composed only of a first component containing at least one member of the liquid crystalline compound expressed by the formula (1), but the composition is preferred to blend therewith, at least one member of compounds selected from the group consisting of those expressed by the formulas (2), (3) and (4) (hereinafter abbreviated to the second A component), and/or at least one member of compounds selected from the group consisting of those expressed by the formulas (5), (6), (7), (8) and (9) (hereinafter abbreviated to the second B component), and further, it is possible to additionally blend known compounds as the third component, in order to adjust the threshold voltage, liquid crystal phase temperature range, optical anisotropy value, dielectric anisotropy value or viscosity. As preferred examples of compounds contained in those expressed by the formulas (2), (3) and (4), among the second A component, the following compounds of (2-1) to (2-15), (3-1) to (3-48) and (4-1) to (4-55) can be respectively mentioned: The compounds expressed by these formulas (2) to (4) exhibit a positive dielectric anisotropy value and far suprior thermal stability and chemical stability. As to the quantity of the compounds used, a range of 1 to 99% by weight based upon the total weight is suitable, and that of 10 to 97% by weight is preferred, and that of 40 to 95% by weight is more preferred. Next, as preferred examples of the compounds expressed by the formulas (5), (6) and (7), among the above second B component, the following (5-1) to (5-29), (6-1) to (6-3) and (7-1) to (7-17) can be mentioned: The compounds expressed by the formulas (5) to (7) exhibit a positive and large dielectric anisotropy value and are used as composition component, particularly in order to reduce the threshold voltage. Further, the compounds are used for adjusting the viscosity and the optical anisotropy value and for broadening the liquid crystal phase temperature range, and further for improving the steepness. Further, as preferable examples of compounds included in those of the formulas (8) and (9), among those of the second B component, the following (8-1) to (8-16) and (9-1) to (9-16) can be mentioned: The compounds expressed by the formulas (8) and (9) exhibit a negative or weakly positive dielectric anisotropy value, and among these compounds, those expressed by the formula (8) are used as a composition component, mainly for lowering the viscosity and adjusting the optical anisotropy value, and those expressed by the formula (9) are used for broadening the liquid crystal phase temperature range and/or for adjusting the optical anisotropy value. The compounds expressed by the formulas (5) to (9) are indispensable for preparing liquid crystal compositions, particularly for STN type display mode or usual TN type display mode. As to the quantity of these compounds used, when liquid crystal compositions for usual STN type display mode or TN type display mode are prepared, a range of 1 to 99% by weight based upon the total quantity of the liquid crystal compositions is suitable, and a range of 10 to 97% is preferred and that of 40 to 95% by weight is more preferred. The liquid crystal composition provided by the present invention is preferred to contain at least one member of the liquid crystal compound expressed by the formula (1) in a proportion of 0.1 to 99% by weight, for exhibiting superior characteristics. The liquid crystal composition is generally prepared according to a known process, for example according to a process wherein various components are mutually dissolved at high temperatures. Further, if necessary, by adding a suitable additive, improvement is made depending upon the aimed use applications and the composition is optimized. Such additives are well known by preson of ordinary skill in the art and described in literatures, etc. in details. Usually, a chiral dopant having an effect of inducing the helical structure to thereby adjust a necessary twist angle and prevent the reverse twist, is added. Further, when a dichroic pigment such as those of mellocyanine group, styryl group, azo group, azomethine group, azoxy group, quinophthalone group, anthraquinone group, tetrazine group, etc. is added, the resulting composition can be also used as that of GH mode. The composition of the present invention is usable for NCAP prepared by microcapsulating nematic liquid crystals, polymer-dispersion type, liquid crystal display element prepared by forming three-dimensional, reticulated high molecules in liquid crystals (PDLCD), for example, polymer network liquid crystal display element (PNLCD) and besides, as liquid crystal compositions for birefringence control (ECB) mode or DS mode. As liquid crystal composition examples containing the compound of the present invention, the following ones can be mentioned: In addition, the numbers of the compounds are the same as those shown in the below-mentioned Examples. Composition example 1 Composition example 2 Example The present invention will be described in more details by way of Examples. In addition, in the respective Examples, Cr, S A , S B , S c , S X , N and Iso, respectively represent crystal, smectic A phase, smectic B phase, smectic C phase, smectic phase whose phase structure has not yet been analyzed, nematic phase, and isotropic liquid. The unit of the phase transition temperatures all refer to °C. Example 1 Preparation of 3,5-difluoro-4-cyanophenyl 2-fluoro-4-(propoxymethyl)benzoate (in the formula (1), R=C 3 H 7 , ℓ=1, m=0, n = 0, A 3 =2-fluoro-1,4-phenylene group, Z 1 =-COO-, X=CN and Y 1 and Y 2 = both, F) (Compound No. 1) 2-Fluoro-4-(propoxymethyl)benzoate (1.5 g, 7.1 mmol) was mixed with thionyl chloride (1.3 g, 10.6 mmol), pyridine (0.1 mℓ) and toluene (3 mℓ), followed by reacting them at 80°C for 2 hours, and distilling off superfluous thionyl chloride and toluene under reduced pressure, to obtain raw 2-fluoro-4-(propoxymethyl)benzoyl chloride. Next, 2,6-difluoro-4-hydroxybenzonitrile (1.1 g, 7.1 mmol), pyridine (0.8 mℓ) and toluene (2 mℓ) were mixed. To this mixture was dropwise added a toluene 3 mℓ solution of the above 2-fluoro-4-(propoxymethyl)benzoyl chloride at room temperature for 10 minutes, followed by reacting them at 50°C for 2 hours, adding water (10 mℓ) to the reaction product, extracting with toluene (50 mℓ), washing the resulting organic layer three times with 6N-HCℓ, three times with 2N-NaOH and three times with water, drying over anhydrous magnesium sulfate, distilling off the solvent under reduced pressure, subjecting the residue to silica gel column chromatography (eluent: toluene), to obtain raw 3,5-difluoro-4-cyanophenyl 2-fluoro-4-(propoxymethyl)-benzoate (2.4 g) and recrystallizing this product from heptane/ether (8/2), to obtain the captioned compound (1.6 g, yield: 64.8%). Cr 23.5-24.3 Iso Further, the mass spector data well supported its structure. Mass analysis: 350 (M+1) According to the process of Example 2, the following compounds (No. 2 to No. 10) are prepared, wherein A = - (A 1 -Z 1 ) m - (A 2 -Z 2 ) n -(A 3 -Z 3 ) 0 - Hereinafter, examples using the compound of the present invention as a component of liquid crystal compositions will be described. In the use examples, NI, Δε, Δn, η and V 10 , respectively represent clearing point (°C), dielectric anisotropy value, optical anisotropy value, viscosity at 20°C (mPa·s) and threshold voltage (V). Example 2 (Use example 1) The physical properties of nematic liquid crystal composition of composition example 1 were as follows: NI: 81.9, Δε: 22.6, Δn: 0.147, η: 49.3, Vth: 1.07. This composition was allowed to stand in a freezer at -20°C, but any deposition of crystals and smectic phase were not observed even after 60 days. Example 3 (Use example 2) The physical properties of nematic liquid crystal composition of composition example 3 were as follows: NI: 92.2, Δε: 10.5, Δn: 0.163, η: 18.6, Vth: 1.68. This composition was allowed to stand in a freezer at -20°C, but any deposition of crystals and smectic phase were not observed even after 60 days. As seen from the foregoing any of the compounds of the present invention have a large dielectric anisotropy value, a small change in the threshold voltage value depending upon temperatures, and an improved solubility in other liquid crystal materials at lower temperatures. Accordingly, when the compound of the present invention is used as a component of liquid crystal compositions, it is characterized by exhibiting a superior solubility in other liquid crystal materials, and when six-membered ring, substituent and/or bonding group as molecule-constituting elements are adequately selected, it is possible to provde novel liquid crystal compositions having desired physical properties.

Claims: A liquid crystalline compound expressed by the formula (1): wherein R represents an alkyl group of 1 to 10 carbon atoms; ℓ represents an integer of 1 to 9; m and n each independently represent 0 or 1; A 1 , A 2 and A 3 each independently represent trans-1,4-cyclohexylene group, 1,4-phenylene group, pyrimidine-2,5-diyl group, pyridine-2,5-diyl group or 1,3-dioxane-2,5-diyl group with the proviso that at least one of A 1 , A 2 and A 3 is 1,4-phenylene group in which one or more hydrogen atoms on the ring are replaced by F; Z 1 , Z 2 and Z 3 each independently represent -COO-, -(CH 2 ) 2 - or a covalent bond at least one of which represents -COO-; provided that when m + n = 1, then Z 3 represents -COO-. A liquid crystal composition characterized by containing at least one member of the liquid crystalline compound set forth in claim. 1 A liquid crystal composition characterized by containing as a first component, at least one member of the liquid crystalline compounds set forth in claim 1 , and as a second component, at least one member selected from the group consisting of compounds expressed by the following formulas (2), (3) and (4): in these formulas, R 1 represents an alkyl group of 1 to 10 carbon atoms; X 1 represents F, Cℓ, OCF 3 , OCF 2 H, CF 3 , CF 2 H or CFH 2 ; L 1 , L 2 , L 3 and L 4 each independently represent H or F; Z 4 and Z 5 each independently represent -(CH 2 ) 2 -, -CH=CH- or a covalent bond; and a represents 1 or 2. A liquid crystal composition characterized by containing as a first component, at least one member of the liquid crystalline compounds set forth in claim 1 and as a second component, at least one member selected from the group consisting of compounds expressed by the following formulas (5), (6), (7), (8) and (9) : in the formula (5), R 2 represents F, an alkyl group of 1 to 10 carbon atoms or an alkenyl group of 2 to 10 carbon atoms, one or more non-adjacent methylene groups (-CH 2 -) in the alkyl group or the alkenyl group may be replaced by oxygen (-O-); ring A represents trans-1,4-cyclohexylene group, 1,4-phenylene group, pyrimidine-2,5-diyl group or 1,3-dioxane-2,5-diyl group; ring B represents trans-1,4-cyclohexylene group, 1,4-phenylene group or pyrimidine-2,5-diyl group; ring C represent trans-1,4-cyclohexylene group or 1,4-phenylene group; Z 6 represents -(CH 2 ) 2 -, -COO- or a covalent bond; L 5 and L 6 each independently represent H or F; b and c each independently represent 0 or 1; in the formula (6), R 3 represents an alkyl group of 1 to 10 carbon atoms; L 7 represents H or F; and d represents 0 or 1; in the formula (7), R 4 represents an alkyl group of 1 to 10 carbon atoms; rings D and E each independently represent trans-1,4-cyclohexylene group or 1,4-phenylene group; Z 7 and Z 8 each independently represent -COO- or a covalent bond; Z 9 represents -COO- or -C≡C-; L 8 and L 9 each independently represent H or F; X 2 represents F, OCF 3 , OCF 2 H, CF 3 , CF 2 H or CFH 2 , but when X 2 represents OCF 3 , OCF 2 H 2 , CF 3 , CF 2 H or CFH 2 , L 8 and L 9 both represent H; and e, f and g each independently represent 0 or 1; in the formula (8), R 5 and R 6 each independently represent an alkyl group of 1 to 10 carbon atoms or an alkenyl group of 2 to 10 carbon atoms, and in either of the groups, one or more non-adjacent methylene groups (-CH 2 -) may be replaced by oxygen (-O-); ring G represents trans-1,4-cyclohexylene group, 1,4-phenylene group or pyrimidine-2,5-diyl group; ring H represents trans-1,4-cyclohexylene group or 1,4-phenylene group; Z 10 represents -C≡C-, -COO-, -(CH 2 ) 2 -, -CH=CH-C≡C- or a covalent bond; and Z 11 represents -COO- or a covalent bond; and in the formula (9), R 7 and R 8 each independently represent an alkyl group of 1 to 10 carbon atoms or an alkenyl group of 2 to 10 carbon atoms, and in either of the groups, one or more non-adjacent methylene groups (-CH 2 -) may be replaced by oxygen (-O-); ring I represents trans-1,4-cyclohexylene group, 1,4-phenylene group or pyrimidine-2,5-diyl group; ring J represents trans-1,4-cyclohexylene group, or 1,4-phenylene group, or pyrimidine-2,5-diyl group, one or more hydrogen atoms on the rings of which groups may be replaced by F, ring K represents trans-1,4-cyclohexylene group or 1,4-phenylene group; Z 12 and Z 14 each independently represent -COO-, -(CH 2 ) 2 - or a covalent bond; Z 13 represents -CH=CH-, -C≡C-, -COO- or a covalent bond; and h represents 0 or 1. A liquid crystal composition, characterized by containing as a first component, at least one member of the liquid crystalline compounds set forth in claim 1 as a part of a second component, at least one member selected from the group consisting of the compounds expressed by the formulas (2), (3) and (4) set forth in claim 3 , and as another part of the second component, at least one member selected from the group consisting of the compounds expressed by the formulas (5), (6), (7), (8) and (9) set forth in claim 4. A liquid crystal display element composed of a liquid crystal composition set forth in either one of claim 2 to 5.

Inventors: HACHIYA NORIHISA, HASEBA YASUHIRO, KOIZUMI YASUYUKI, KONDO TOMOYUKI, MATSUI SHUICHI, MIYAZAWA KAZUTOSHI, NAKAGAWA ETSUO, SHIBATA KOICHI, HACHIYA, NORIHISA, HASEBA, YASUHIRO, KOIZUMI, YASUYUKI, KONDO, TOMOYUKI, MATSUI, SHUICHI, MIYAZAWA, KAZUTOSHI, NAKAGAWA, ETSUO, SHIBATA, KOICHI
Applicants: CHISSO CORP, CHISSO CORPORATION
Application year: 1996
Main classification: C07C255
IPC codes: C09K19, C07C69