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  • C09K19/06—Non-steroidal liquid crystal compounds
  • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
  • C09K19/10—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings
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  • C07C43/20—Ethers having an ether-oxygen atom bound to a carbon atom of a six-membered aromatic ring
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  • C07C43/20—Ethers having an ether-oxygen atom bound to a carbon atom of a six-membered aromatic ring
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  • C07C45/673—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups by isomerisation; by change of size of the carbon skeleton by change of size of the carbon skeleton
  • C07C45/676—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups by isomerisation; by change of size of the carbon skeleton by change of size of the carbon skeleton by elimination of carboxyl groups
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  • C07C49/587—Unsaturated compounds containing a keto groups being part of a ring
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  • C07C49/587—Unsaturated compounds containing a keto groups being part of a ring
  • C07C49/657—Unsaturated compounds containing a keto groups being part of a ring containing six-membered aromatic rings
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  • C07C49/587—Unsaturated compounds containing a keto groups being part of a ring
  • C07C49/753—Unsaturated compounds containing a keto groups being part of a ring containing ether groups, groups, groups, or groups
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  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
  • C07C69/013—Esters of alcohols having the esterified hydroxy group bound to a carbon atom of a ring other than a six-membered aromatic ring
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  • C09K19/00—Liquid crystal materials
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  • C09K19/00—Liquid crystal materials
  • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
  • C09K19/06—Non-steroidal liquid crystal compounds
  • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
  • C09K19/10—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings
  • C09K19/12—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings at least two benzene rings directly linked, e.g. biphenyls
  • C09K19/126—Compounds containing at least one asymmetric carbon atom
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  • C09K19/00—Liquid crystal materials
  • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
  • C09K19/06—Non-steroidal liquid crystal compounds
  • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
  • C09K19/30—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing saturated or unsaturated non-aromatic rings, e.g. cyclohexane rings
  • C09K19/3001—Cyclohexane rings
  • C09K19/3003—Compounds containing at least two rings in which the different rings are directly linked (covalent bond)
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  • C09K19/00—Liquid crystal materials
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  • C09K19/06—Non-steroidal liquid crystal compounds
  • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
  • C09K19/30—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing saturated or unsaturated non-aromatic rings, e.g. cyclohexane rings
  • C09K19/3098—Unsaturated non-aromatic rings, e.g. cyclohexene rings
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  • C09K19/00—Liquid crystal materials
  • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
  • C09K19/42—Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40
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  • C07C2601/00—Systems containing only non-condensed rings
  • C07C2601/12—Systems containing only non-condensed rings with a six-membered ring
  • C07C2601/14—The ring being saturated
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  • C07C2601/16—Systems containing only non-condensed rings with a six-membered ring the ring being unsaturated

Definitions

• the present invention relates to liquid crystal materials for use in ferroelectric liquid crystal display devices. More specifically, the invention relates to chiral, laterally substituted derivatives of cyclohexene, cyclohexane, benzene, biphenyl, terphenyl and quaterphenyl compounds, mixtures thereof, and liquid crystal displays utilizing the same.
• Liquid crystal displays have been commonly employed in electronic devices for many years. In general, commercial displays operate by the twisted nematic (TN) or super twisted nematic (STN) technique. However, liquid crystal displays based on a ferroelectric technique are also known. Such displays have superior properties such as higher switching efficiencies in comparison to TN and STN displays. But ferroelectric liquid crystal displays have not been widely used in commercial or consumer applications, in spite of their advantages, due to their limited operable temperature range. Specifically, in order to utilize the ferroelectric effect, the liquid crystal material must exhibit a smectic C phase. Liquid crystal compounds that exhibit a smectic C phase do so over a narrow temperature range.
• Liquid crystal compounds include derivatives of cyclohexane, cyclohexene, benzene, biphenyl, and terphenyl compounds. Such compounds are disclosed in Ferroelectrics 1991, vol. 114, p.
• U.S. P. 4,784,793 addresses some of the problems encountered with ferroelectric liquid crystal materials and proposes the use of terpenoid derivatives, such as an ester of a terpenoid alcohol, as either a smectic host or a chiral dopant.
• U.S. P. 5,382,380 and U.S. P. 5,494,605 both relate to p-terphenyl derivatives having lateral fluoro substitution. The compounds are described as exhibiting a smectic C phase over a wide temperature range.
• the compounds of the prior art are not yet fully satisfactory and do not satisfy all of the requirements for some of the new applications for liquid crystal displays. Specifically, compounds are needed that will allow the formation of ferroelectric liquid crystal mixtures exhibiting a low crystalline to smectic C phase transition temperature as well as a wide smectic C phase and that has a stable orientation.
• a further object of the invention is to provide a ferroelectric liquid crystal display device that is operable over a wide range of temperatures and at very low temperatures.
• R 1 and $ are each independently selected from the group consisting of formulas S 1 , S 2 and S 3 : I I
• Y 1 , Y 2 , Y 3 , and Y are each independently hydrogen, alkyl, F, CN, CF, or OCF 3 , n, p, and k are each independently an integer from 0 to 7. and m and 1 are each independently zero or 1, with the proviso that at least one of R 1 and R 2 is a chiral radical;
• Z 1 and Z 2 are each independently a ring selected from the group consisting of formulas 2-11
• a 1 , A 2 and A 3 are each independently a ring group selected from the group consisting of formulas 12-19:
• the compounds of Formula (1) can have as few as one ring represented by Z 1 or a plurality of rings represented by Z 1 and any of A 1 -A 3 and/or Z 2 .
• a is 0, then the substituent group R 1 is directly bonded to the group Z 1 .
• b, c and d were each 0, the group R 2 would be directly bonded to the moiety Z 1 .
• R 1 and R 2 are each independently represented by one of the formulas S 1 - S 3 with the proviso that at least one of R ! and R 2 is a chiral group.
• R l and R 2 can both be chiral groups, although such is not required.
• the compounds of Formula (1) are optically active.
• a chiral moiety can be obtained by appropriately selecting the groups for the pair Y 1 and Y 2 or the pair Y 3 and Y 4 , as will be readily understood by workers skilled in the art.
• the groups Y 1 -Y 4 are independently selected for R 1 and R 2 . That is, the Y 1 group of R 1 may be the same or different as the Y 1 group of R 2 .
• the same is true of all other variables in the formulas S 1 - S 3 such that the values selected for R 1 are independent of the values selected for R 2 .
• Y ] , Y 2 , Y 3 or Y 4 represents an alkyl, it may be straight or branched and typically has from 1 to 12 carbon atoms.
• the alkyl group has from 1 to 8 carbon atoms.
• examples of the alkyl group include methyl, ethyl, n-propyl, i-propyl, n-butyl, and t-butyl.
• the subscripts n, p and k are each independently an integer from 0 to 7 while the subscripts m and 1 are each independently 0 or 1.
• p and k, as well as 1, are 0.
• Examples of chiral R 1 and R 2 groups include 2-methylbutyl, 2-methylpentyl, 2-methylhexyl, 4-methylhexyl, citronellyl, citronellyloxy, 2-methylhexyloxy, 2- methyloctyloxy, 2-cyanobutyloxy, and 2-fluorobutyloxy.
• the non-chiral R 1 and R 2 groups include octyl, octyloxy, butyl, hexyl, hexyloxy, nonyl, nonyloxy, decyl, decyloxy, 2-octyloxyethyl, 2-octyloxyethyloxy, heptyloxymethyl, and heptyloxymethyloxy .
• Z 1 and Z 2 each independently represent a six-membered ring selected from formulas 2-11 , each of which is substituted by a group X .
• Each X independently represents O, F, Cl, OH, CN or a group represented by formulas L 1 - L 6 .
• X can not be O on ring formulas 4, 5, and 8-11.
• Z 2 is present (c is 1), each X group is independently selected.
• L ' - L 6 examples include 2-methylbutyloxycarbonyl, 2-methylbutylcarbonyloxy, 2- methylhexyloxy, 2-methyloctyloxy, 2-methylbutyl, 2-methylbutyloxy, 2- chlorobutylcarbonyloxy, methyl, methyloxy, ethyl, and ethyloxy.
• L 1 - L 6 can represent chiral or non- chiral groups.
• a 1 - A 3 are each independently selected from the ring formulas 12 - 19.
• 1 - X 4 are independently selected for each of A 1 - A 3 and are H, F, or Cl.
• the chiral, laterally substituted compounds of formula (1) are liquid crystal compounds that exhibit a chiral smectic C phase.
• the compounds exhibit a chiral smectic C phase over a broad temperature range, such as over a range of at least 20°C, more preferably at least 30°C, and most preferably over at least 40 °C range.
• the compounds exhibit a chiral smectic C phase at low temperatures, including ambient temperatures. Accordingly, it is preferred that the lower end of the chiral smectic C phase is 20 °C or less, more preferably 10°C or less, and most preferably, 5°C or less.
• the smectic C phase temperature values can be determined by conventional techniques known in the art; i.e., heating the compounds to the isotropic liquid phase, and then observing the phases and their transition temperatures during cooling and then heating again.
• the transition temperatures were determined using a Mettler FP5 hotstage and control unit in conjunction with a polarizing microscope and these values were confirmed using differential scanning calorimetry (Perkin-Elmer DSC- 7).
• the compound of formula (1) is represented by one of the formulas 1.1 - 1.39 set forth below.
• R 3 and R 4 represent a group of formulas L 1 - L 6
• R 1 , R 2 , and X 1 - X 4 have the same definition as in formula (1).
• R 1 and R 2 are each independently selected from the group consisting of formulas S 1 , S 2 and S 3 :
• Y 1 , Y 2 , Y 3 , and Y 4 are each independently hydrogen, alkyl, F, CN, CF 3 or OCF 3 , n, p, and k are each independently an integer from 0 to 7, and m and 1 are each independently zero or 1 , with the proviso that at least one of R 1 and R 2 is a chiral radical;
• Z 1 and Z 2 are each independently a ring selected from the group consisting of formulas 2-11
• the compounds of formula (1) can be prepared by workers skilled in this art without undue experimentation through conventional reactions that are per se known in the art and from conventional and/or commercially available starting materials. However, preferred reaction schemes are set forth hereinbelow. Liquid crystal compounds according to the present invention can be obtained by the transformation of 3,6-disubstituted cyclohex-2-enones. Synthesis of these starting compounds is shown in scheme 1. For convenience and clarity the compounds are shown without the subscripts a - d, but such should be assumed to be present.
• Scheme 1 The process consists of heating acetoacetic esters with hydrochloride 4- substituted ⁇ -N-dimethylaminoprophio-phenones in the presence of an alkaline hydroxide. The 3,6-disubstituted cyclohex-2-enones can then be transformed into
• the 3,6-disubstituted cyclohex-2-enones can be transformed into the corresponding 4,4-disubstituted 3-hydroxybiphenyls, te ⁇ henyls and quate ⁇ henyls (Formula 27) by aromatization in the presence of 10% palladium on carbon at 200°C or by the boiling of them in alcohols in the presence of iodine.
• the 3,6-disubstituted cyclohexanones can be transformed into the corresponding cis and trans alcohols (Formula 34) by reduction with NaBH 4 or LIA1H 4 in an appropriate solvent.
• Fluorosubstituted compounds are prepared by heating ketones (Formula 24) with diethylaminosulfur trifluoride in benzene or methylene chloride and the resulting difluoroderivatives (Formula 36) are then treated with a base, advantageously KOH or with alcohalate.
• the cyanounsaturated compounds (Formula 42, 43) are obtained by treating the ketones (Formula 24) with acetone cyanohydrine in the presence of tertiary amines or alkaline metal carbonates in dioxane or tetrahydrofuran and then by treating of the corresponding cyanoalcohols with POCl 3 in the presence of a tertiary aliphatic amine or pyridine.
• the isomeric compounds (Formula 42, 43) are separated by crystallization.
• the chlorine substituted compounds (Formulae 26, 30, 31) are obtained by heating ketone (Formula 23, 24) with PC1 5 , PCI, in hexane or benzene.
• the isomeric compounds (Formula 30, 31) are separated by crystallization or used in a form of the isomeric mixtures.
• Compounds of Formula 25 and 32 are obtained from ketone (Formula 23,
• Compounds of Formula 36 are obtained by treating ketone 24 with triethyl orthoformate in the presence of p-toluenesulfonic acid in ethanol.
• the chlorocyclohexane derivatives (Formula 33) are obtained by treating the corresponding alcohols (Formula 34) with PC1 5 , SOCl 2 , POCl 3 .
• the fluorocyclohexane derivatives (Formula 40) are synthesized by treating the alcohols 34 with diethylaminosulfur trifluoride (DAST) in methylene chloride at temperature below 20°C.
• DAST diethylaminosulfur trifluoride
• the compounds of formula (1) are useful in liquid crystal display devices including TN, STN, and ferroelectric LC displays.
• the compounds of Formula (1) are especially useful in creating compositions having various values of optical anisotropy and dielectric anisotropy as well as a wide temperature interval of the smectic C phase.
• Compositions according to the present invention require at least two compounds, with at least one of them being a compound of Formula (1).
• the compounds contained in the composition can be exclusively of formula (1) or a combination with other liquid crystal compounds.
• compositions containing compounds of Formula (1) that have 2 or 3 rings show low or intermediate clearing temperatures.
• Compositions containing compounds of Formula (1) that have 4 or 5 rings have a broadening of the smectic C phase, including broader than 100°C.
• the compositions are useful in ferroelectric liquid crystal displays, TN, STN, and active matrix displays. The high chemical stability and resistivity of these mixtures enable the stable performance of the display.
• the composition is a ferroelectric composition and exhibits a chiral smectic C phase over a broad temperature range, preferably over at least a 40 °C interval. Moreover, preferably the composition simultaneously exhibits a lower end of the chiral smectic C phase at 10°C or less, more preferably at 10°C or less, and most preferably at -30°C or less.
• one or more compounds of Formula (1) is combined with at least one liquid crystal pyrimidine derivative.
• the pyrimidine derivative exhibits a smectic C phase and is capable of forming a ferroelectric liquid crystal composition.
• Such compounds include phenyl -substituted pyrimidines such as 2-alkoxyphenyl-5-alkylpyrimidines where the alkoxy and alkyl groups each contain from 1 to 12 carbon atoms.
• the composition of the present invention can be used in any conventional liquid crystal display device.
• such devices generally comprise two parallel electrodes, at least one of which is transparent, and having a layer of the liquid crystal composition disposed therebetween.
• die liquid crystal layer is typically disposed between two parallel plates, one of which is transparent, that are in turn supported by (or surrounded by) the parallel electrodes. Between the parallel plates there may also be one or more of an aligning layer, isolating layer, and colored filter layer.
• the display device is operated by the ferroelectric effect.
• the compounds of formula (1) are useful in liquid crystal display devices including TN, STN, and ferroelectric LC displays.
• the compounds of Formula (1) are especially useful in creating compositions having various values of optical anisotropy and dielectric anisotropy as well as a wide temperamre interval of the smectic C phase.
• the compound of the present invention can be used in any conventional liquid crystal display device.

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• 1997
  • 1997-09-11 EP EP97939250A patent/EP0946672A1/de not_active Withdrawn
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