EP4669720A1 - DIHYDRONAPHTHAL INDIVATES - Google Patents

DIHYDRONAPHTHAL INDIVATES

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Publication number
EP4669720A1
EP4669720A1 EP24706121.1A EP24706121A EP4669720A1 EP 4669720 A1 EP4669720 A1 EP 4669720A1 EP 24706121 A EP24706121 A EP 24706121A EP 4669720 A1 EP4669720 A1 EP 4669720A1
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EP
European Patent Office
Prior art keywords
denotes
atoms
compounds
alkyl
formula
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
EP24706121.1A
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German (de)
French (fr)
Inventor
Constanze Brocke
Andreas Taugerbeck
Dagmar Klass
Matthias Jost
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Merck Patent GmbH
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Merck Patent GmbH
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Publication of EP4669720A1 publication Critical patent/EP4669720A1/en
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • 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
    • C09K19/32—Non-steroidal liquid crystal compounds containing condensed ring systems, i.e. fused, bridged or spiro ring systems
    • C09K19/322—Compounds containing a naphthalene ring or a completely or partially hydrogenated naphthalene ring
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • 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
    • C09K19/14—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings linked by a carbon chain
    • C09K19/18—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings linked by a carbon chain the chain containing carbon-to-carbon triple bonds, e.g. tolans
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • 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
    • C09K2019/121—Compounds containing phenylene-1,4-diyl (-Ph-)
    • C09K2019/123—Ph-Ph-Ph
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • 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
    • C09K19/14—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings linked by a carbon chain
    • C09K19/18—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings linked by a carbon chain the chain containing carbon-to-carbon triple bonds, e.g. tolans
    • C09K2019/181—Ph-C≡C-Ph
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • 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
    • C09K19/14—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings linked by a carbon chain
    • C09K19/18—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings linked by a carbon chain the chain containing carbon-to-carbon triple bonds, e.g. tolans
    • C09K2019/183—Ph-Ph-C≡C-Ph
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • 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)
    • C09K2019/3016—Cy-Ph-Ph
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • 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
    • C09K19/3059—Cyclohexane rings in which at least two rings are linked by a carbon chain containing carbon to carbon triple bonds
    • C09K2019/3063—Cy-Ph-C≡C-Ph
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • 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
    • C09K19/32—Non-steroidal liquid crystal compounds containing condensed ring systems, i.e. fused, bridged or spiro ring systems
    • C09K19/322—Compounds containing a naphthalene ring or a completely or partially hydrogenated naphthalene ring
    • C09K2019/324—Compounds containing a naphthalene ring or a completely or partially hydrogenated naphthalene ring containing a dihydronaphthalene

Definitions

  • the present invention relates to dihydronaphthalene derivatives, to liquid-crystalline media comprising same, and to high-frequency components comprising these media, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, tunable filters, tunable metamaterial structures, and electronic beam steering antennas (e.g., phased array antennas), and to devices comprising said components.
  • the invention further relates to an optical component comprising said liquid-crystalline media, operable in the infrared region (IR) of the electromagnetic spectrum.
  • IR infrared region
  • the invention further relates to the use of said LC medium in the infrared region and to devices comprising said optical component.
  • Liquid-crystalline media have been used for many years in electro-optical displays (liquid crystal displays: LCDs) in order to display information. More recently, however, liquid-crystalline media have also been proposed for use in components for microwave technology, such as, for example, in DE 102004029429 A and in JP 2005- 120208 (A).
  • An object of the present invention is to provide a compound for the use in liquid crystalline media with improved properties relevant for the application in the microwave range of the electromagnetic spectrum.
  • a compound of formula D defined below is provided and a liquid crystalline medium comprising the compound.
  • the present invention relates to a compound of formula D in which R D denotes H, straight-chain alkyl having 1 to 12 C atoms or branched alkyl having 2 to 12 C atom, or straight-chain alkenyl having 2 to 12 C atoms, or branched alkenyl having 3 to 12 C atoms, or straight-chain alkynyl having 2 to 12 C atoms or branched alkynyl having 4 to 12 C atoms, in which one or more CH 2 -groups may be replaced by , and where one or more non-adjacent CH 2 -groups may be replaced by O, or alternatively denotes a group R P , R P denotes halogen, CN, NCS, R F -,
  • a liquid crystal medium comprising one or more compounds of formula D.
  • Preferred embodiments of the present invention are subject-matter of the dependent claims or can also be taken from the description.
  • the media according to the invention comprising the compound according to the invention are distinguished by an improved figure-of-merit ⁇ due to a higher tunability ⁇ and lower dielectric loss.
  • the media according to the present invention are further distinguished by a high clearing temperature, a broad nematic phase range and excellent low-temperature stability (LTS).
  • LTS low-temperature stability
  • devices containing the media are operable under extreme temperature conditions.
  • the media are further distinguished by high values of the dielectric anisotropy and low rotational viscosities.
  • the threshold voltage i.e. the minimum voltage at which a device is switchable, is very low.
  • a low operating voltage and low threshold voltage is desired in order to enable a device having improved switching characteristics and high energy efficiency.
  • Low rotational viscosities enable fast switching of the devices according to the invention.
  • a component and a device comprising said component, both operable in the microwave region of the electromagnetic spectrum.
  • Preferred components are phase shifters, varactors, wireless and radio wave antenna arrays, matching circuits and adaptive filters.
  • the medium according to the invention is likewise suitable for use in the infrared region of the electromagnetic spectrum.
  • the invention thus further relates to the use of the medium defined above in the infrared region of the electromagnetic spectrum, preferably in the A-band, and/or B- band and/or C-band, for phase modulation of said infrared light.
  • an optical component comprising the liquid crystal medium according to the invention sandwiched between a pair of substrates.
  • the invention further relates to a device comprising the optical component according to the invention.
  • Preferred devices are infrared imagers, wavelength selective switches, LCoS-SLM, LIDAR systems, wavelength-division multiplexing (WDM) systems, reconfigurable optical add-drop multiplexer (ROADM), and nonmechanical beam steering, e.g.
  • a method of spatially modulating infrared light comprising, i) providing an optical component comprising first and second substrates facing each other and each having a surface, the first substrate comprising at least one first electrode, the second substrate comprising at least one second electrode, the component further comprising a liquid crystal layer sandwiched between the first and second substrates wherein the liquid crystal comprises one or more compounds selected from the compounds of formula D indicated above; ii) receiving incident infrared light at a surface of said optical component; iii) applying a predetermined voltage to each of the individual electrodes formed on the first and second substrate in order to modulate a refractive index of the liquid crystal layer.
  • an optical phase modulator comprising at least the steps of a) providing a first substrate with a first electrode, optionally having a two dimensional array of individually electrically drivable cells; b) depositing a liquid crystal medium as set forth in claim 1 over the first substrate; and c) mounting a second substrate with a second electrode onto the liquid crystal material.
  • the optical component according to the invention is distinguished by excellent operational stability when exposed to the environment because of high clearing temperature, broad nematic phase range and excellent low-temperature stability (LTS) of the liquid crystal medium used therein. As a result, the component and devices containing the component are operable under extreme temperature conditions.
  • the media used in the component according to the invention are distinguished by high values of the dielectric anisotropy and low rotational viscosities.
  • the threshold voltage i.e. the minimum voltage at which a device is switchable
  • a low operating voltage and low threshold voltage is desired in order to enable a device having improved switching characteristics and high energy efficiency.
  • Low rotational viscosities enable fast switching of the components and devices according to the invention.
  • “high-frequency technology” means applications of electromagnetic radiation having frequencies in the range of from 1 MHz to 1 THz, preferably from 1 GHz to 500 GHz, more preferably 2 GHz to 300 GHz, particularly preferably from about 5 GHz to 150 GHz.
  • infrared region of the electromagnetic spectrum is taken to mean the spectral region of electromagnetic radiation having a wavelength in the range of from 0.75 ⁇ m to 1000 ⁇ m.
  • infrared A is taken to mean the spectral region of electromagnetic radiation having a wavelength in the range of from 0.75 ⁇ m to 1.4 ⁇ m.
  • infrared B is taken to mean the spectral region of electromagnetic radiation having a wavelength in the range of from 1.4 ⁇ m to 3 ⁇ m.
  • infrared C is taken to mean the spectral region of electromagnetic radiation having a wavelength in the range of from 3 ⁇ m to 1000 ⁇ m.
  • the optical component according to the invention operates at a wavelength in the range of from 750 nm to 2500 nm, in particular from 1530 nm to 1565 nm.
  • a very preferred light source for applications according to the invention is an IR laser emitting light with a wavelength of 1,55 ⁇ m or an IR laser emitting light with a wavelength of 905 nm.
  • halogen is F, Cl, Br or I, preferably F or Cl, particularly preferably F.
  • alkyl is straight-chain or branched or cyclic and has 1 to 15 C atoms, is preferably straight-chain and has, unless indicated otherwise, 1, 2, 3, 4, 5, 6 or 7 C atoms and is accordingly preferably methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl or n-heptyl.
  • branched alkyl is preferably isopropyl, s-butyl, isobutyl, isopentyl, 2- methylbutyl, 2-methylhexyl or 2-ethylhexyl.
  • cyclic alkyl is taken to mean straight-chain or branched alkyl or alkenyl having up to 12 C atoms, preferably alkyl having 1 to 7 C atoms, in which a group CH 2 is replaced with a carbocyclic ring having 3 to 5 C atoms, very preferably selected from the group consisting of cyclopropylalkyl, cyclobutylalkyl, cyclopentylalkyl and cyclopentenylalkyl.
  • an alkoxy radical is straight-chain or branched and contains 1 to 15 C atoms.
  • an alkenyl radical is preferably an alkenyl radical having 2 to 15 C atoms, which is straight-chain or branched and contains at least one C-C double bond. It is preferably straight-chain and has 2 to 7 C atoms.
  • the alkenyl radical can be in the form of E and/or Z isomer (trans/cis). In general, the respective E isomers are preferred.
  • alkenyl radicals prop-2-enyl, but-2- and -3-enyl, and pent-3- and -4-enyl are particularly preferred.
  • alkynyl is taken to mean an alkynyl radical having 2 to 15 C atoms, which is straight-chain or branched and contains at least one C-C triple bond.1- and 2-propynyl and 1-, 2- and 3-butynyl are preferred.
  • R F denotes a halogenated alkyl-, alkoxy-, alkenyl or alkenyloxy it can be branched or unbranched.
  • the compounds of the general formula D are prepared by methods known per se, as described in the literature (for example in the standard works, such as Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Georg-Thieme- Verlag, Stuttgart), and under reaction conditions which are known and are suitable for said reactions. Use can be made here of variants which are known per se, but are not mentioned here in greater detail. If desired, the starting materials can also be formed in situ by not isolating them from the reaction mixture, but instead by immediately reacting them further into the compounds of the general formula D. Preferred synthetic pathways towards compounds according to the invention are exemplified in the reaction schemes below in which the occurring groups and parameters have the meanings given for formula D.
  • Fluorinated dihydronaphthalenes are described in JP2003-146919A and in JP2003- 183196A.
  • Preferred starting materials are suitably substituted dihydronaphthalenes (1), that carry two different reactive groups X 1 and X 2 . Because of the different reactivity of the groups X 1 and X 2 it is possible by choice of suitable reaction conditions to selectively react one of the groups X 1 and X 2 in a first reaction followed by derivatisation by means of the other group of X 1 and X 2 .
  • Suitable groups X 1 and X 2 are leaving groups selected from but not limited to Cl, Br, I, methane sulfonate (MsO), methylphenyl sulfonate (TsO), trifluoromethane sulfonate (TfO), perfluorononyl sulfonate (NsO), etc.
  • MsO methane sulfonate
  • TsO methylphenyl sulfonate
  • TfO trifluoromethane sulfonate
  • NsO perfluorononyl sulfonate
  • a compound of formula 1 is shown in which X 1 denotes TfO and X 2 denotes Br (1a).
  • the compound 1a can be made from 6-bromo-2-tetralone; 6-chloro and 6-iodo-2- tetralone are also known from the literature and can be reacted in a similar fashion.
  • a process for the fabrication of a compound of formula D is provided in which a compound of the formula (1) is reacted in two steps by two different transition metal catalysed cross coupling reactions (Scheme 1).
  • Scheme 1 Preferred compounds of formula D in which the linking group Z D2 is a triple bond are for example obtained by Sonogashira coupling from the compound 1a.
  • the compound 1 can also be reacted in other cross-coupling reactions, for example Suzuki reactions as described in WO2017133521 A1, to give the intermediate 5; in this embodiment Z D2 of formula D is a single bond (Scheme 2).
  • Scheme 3 Another suitable starting material for the synthesis of the compound according to the invention is 6-hydroxy-2-tetralone in which the hydroxyl group can be fist protected with a suitable phenol protecting group (PG), for example the methoxymethyl group (MOM), as described in the article Katherine M. Byrd, Caitlin N. Kent, and Brian S. J. Blagg, ChemMedChem 2017, 12, 2022 – 2029, which can then be further reacted via the triflate 8 in analogy to the bromo-derivative 1a (scheme 4).
  • PG phenol protecting group
  • MOM methoxymethyl group
  • Scheme 4 The compounds 11 are transferred by the same processes described above into the intermediates 12, (scheme 5) in which G is a group that can be transferred into a group X D : Scheme 5
  • a preferred precursor for the synthesis of the compounds of the formula D is the amino derivative of the formula N1
  • the compounds of formula N1 are reacted with a thiocarbonic acid derivative in which X and Y are leaving groups, or with CS 2 to give the compounds of formula D.
  • Preferred reagents for the process according to the invention for the transformation of compounds of the formula N1 into compounds of the formula D are carbon disulfide, thiophosgene, thiocarbonyl diimidazole, di-2-pyridyl thionocarbonate, bis(dimethylthiocarbamoyl) disulfide, dimethylthiocarbamoyl chloride and phenyl chlorothionoformate, very preferably thiophosgene.
  • Another preferred pathway for the synthesis of isothiocyanates of the formula D includes the reaction of the N-hydroxycarboximidoyl chloride N2 with for example thiourea or a thiocarbonate.
  • the compound of formula D is selected from the compounds of the formulae D-1 and D-2: in which the occurring groups have the meanings given above for formula D, and t2 is 0, 1 or 2, t4 is 0 or 1, and t2+t4 is 1, 2 or 3, preferably 1 or 2.
  • R L on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, or cycloalkyl having 3 to 5 C atoms
  • X D denotes -NCS
  • W denotes N, C-H, C-F or C-Cl
  • Y 1 and Y 2 identically or differently, denote H, Cl, F, methyl or ethyl.
  • t2 and t4 are 0 or 1 where t2 + t4 is 1 or 2.
  • Preferred compounds of the formula D-1 are selected from the following sub-formulae:
  • R D , X D have the meanings defined above and preferably R D denotes straight chain alkyl or alkoxy having 1 to 12 C atoms, or straight chain alkenyl or alkynyl or alkenyloxy or alkynyloxy having 2 to 12 C atoms, or branched or cyclic alkyl or alkoxy or alkenyl or alkenyloxy having 3 to 12 C atoms, more preferably straight chain alkyl having 1 to 7 C atoms or alkynyl having 2 to 7 C atoms, X D denotes NCS, and
  • Y identically or differently, denotes F, Cl or CH 3 , preferably F. more preferably denotes L on each occurrence, identically or differently, denotes F, Cl, CH 3 or C 2 H 5 , and n is 1 or 2, preferably 1.
  • Y identically or differently, denotes F, Cl or CH 3 , preferably F. more preferably denotes L on each occurrence, identically or differently, denotes F, Cl, CH 3 or C 2 H 5 , and n is 1 or 2, preferably 1.
  • Very preferred are the compounds of the formulae D-1-1, D-1-2, D-1-3, D-1-4, D-1-9, D-1-10, D-1-11, D-1-12, D-2-1, D-2-2, D-2-3, D-2-4, D-2-9, D-2-10, D-2-11, and D-2-12.
  • the medium according to the invention comprises one or more compounds selected from the group of compounds of the formulae I, II and III: in which R 1 denotes H, non-fluorinated alkyl or non-fluorinated alkoxy having 1 to 17, preferably 2 to 10 C atoms, or non-fluorinated alkenyl, non-fluorinated alkenyloxy or non-fluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, in which one or more CH 2 -groups may be replaced by preferably non-fluorinated alkyl or non-fluorinated alkenyl, n is 0, 1 or 2, on each occurrence, independently of one another, denote in which R L , on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, preferably H, methyl or ethyl, particularly preferably in which one or more H atoms may be replaced by alkyl having 1 to 6 C atoms or
  • R L preferably denotes H.
  • one or two groups R L preferably one group R L is different from H.
  • the compounds of formula I are selected from the group of compounds of the formulae I-1 to I-5: in which L 1 , L 2 and L 3 on each occurrence, identically or differently, denote H or F, and the other groups have the respective meanings indicated above for formula I and preferably R 1 denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms.
  • the medium comprises one or more compounds selected from the compounds of the formula I-a and optionally one or more compounds selected from the compounds of the formula Cy-1 in which the occurring groups have the meanings given above for formula I-1.
  • the total amount of compounds of the formula I-1 and/or Cy-I in the medium according to the invention is less than 10%, more preferably less than 5%, and in particular less than 2%.
  • the medium contains no compound of formula Cy-1.
  • the media preferably comprise one or more compounds of formula I-1, which are preferably selected from the group of the compounds of the formulae I-1a to I-1d, preferably of formula I-1b: in which R 1 has the meaning indicated above for formula I and preferably denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms.
  • the media preferably comprise one or more compounds of formula I-2, which are preferably selected from the group of the compounds of the formulae I-2a to I-2e, preferably of formula I-2c: in which R 1 has the meaning indicated above for formula I and preferably denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms.
  • the media preferably comprise one or more compounds of formula I-3, which are preferably selected from the group of the compounds of the formulae I-3a to I-3d , particularly preferably of formula I-3b: in which R 1 has the meaning indicated above for formula I and preferably denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms.
  • the media preferably comprise one or more compounds of formula I-4, which are preferably selected from the group of the compounds of the formulae I-4a to I-4e, particularly preferably of formula I-4b:
  • R 1 has the meaning indicated above for formula I and preferably denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms.
  • the media preferably comprise one or more compounds of formula I-5, which are preferably selected from the group of the compounds of the formulae I-5a to I-5d, particularly preferably of formula I-5b: in which R 1 has the meaning indicated above for formula I and preferably denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms.
  • the compounds of formula II-1 are preferably selected from the group of the compounds of the formulae II-1a to II-1e:
  • n denotes an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5
  • z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.
  • the compounds of formula III-1 are preferably selected from the group of the compounds of the formulae III-1a to III-1j, more preferably selected from the group of the compounds of the formulae III-1a, III-1b, III-1g and III-1h, particularly preferably of formula III-1b and/or III-1h:
  • the compounds of formula III-2 are preferably compounds of formula III-2a to III-2l, very preferably III-2b and/or III-2j:
  • n denotes an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5
  • z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.
  • the compounds of formula III-5 are preferably selected from the compounds of formula III-5a:
  • R 3 has the meaning indicated above for formula III-5 and preferably denotes C n H 2n+1 , in which n denotes an integer in the range from 1 to 7, preferably in the range from 2 to 6.
  • the medium comprises one or more compounds of the formula III selected from the group consisting of the formulae IIIa-1 to IIIa-4: in which R 3 has the meanings defined for formula III and preferably denotes straight chain alkyl having 1 to 7 C atoms or branched alkyl having 1 to 9 C atoms, in which one or more CH 2 -groups may be replaced by , , , Very preferred are the compounds of the formulae IIIa-2 and IIIa-3.
  • the media according to the invention comprise one or more compounds selected from the group of compounds of the formulae IIA-1-1 to IIA-1-12, very preferably IIA-1-1 or IIA-1-2:
  • R 1 denotes alkyl or alkenyl having up to 7 C atoms, preferably ethyl, n-propyl, n- butyl or n-pentyl, n-hexyl
  • R L on each occurrence denotes alkyl or alkenyl having 1 to 5 C atoms, or cycloalkyl or cycloalkenyl each having 3 to 6 C atoms, preferably methyl, ethyl, n-propyl, n-butyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclopent-1-enyl, very preferably ethyl, and from which the compounds of formula II-1 are excluded.
  • the liquid-crystalline media according to the present invention in a certain embodiment, which may be the same or different from the previous preferred embodiments preferably comprise one or more compounds of formula IV, s is 0 or 1, preferably 1, and
  • L 4 denotes H or alkyl having 1 to 6 C atoms, cycloalkyl having 3 to 6 C atoms or cycloalkenyl having 4 to 6 C atoms, preferably CH 3 , C 2 H 5 , n-C 3 H 7 , i-C 3 H 7 , cyclopropyl, cyclobutyl, cyclohexyl, cyclopent-1-enyl or cyclohex-1-enyl, and particularly preferably CH 3 , C 2 H 5 , cyclopropyl or cyclobutyl
  • X 4 denotes H, alkyl having 1 to 3 C atoms or halogen, preferably H, F or Cl, more preferably H or F and very particularly preferably F, R 41 to R 44 , independently of one another, denote unfluorinated alkyl or unfluorinated alkoxy, each having 1 to 15 C atoms, unfluorinated alkenyl, unfluorin
  • the compounds of formula IV are selected from the compounds of the formula IV-1 in which R 41 and R 42 , identically or differently, denote alkyl having 2, 3, 4, 5 or 6 C atoms.
  • the liquid-crystal medium additionally comprises one or more compounds selected from the group of compounds of the formulae V, VI, VII, VIII and IX: in which L 51 denotes R 51 or X 51 , L 52 denotes R 52 or X 52 , R 51 and R 52 , independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17, preferably 2 to 10, C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, preferably alkyl or unfluorinated alkenyl, X 51 and X 52 , independently of one another, denote H, F, Cl, -
  • R 81 and R 82 independently of one another, denote H, unfluorinated alkyl or alkoxy having 1 to 15, preferably 2 to 10, C atoms or unfluorinated alkenyl, alkenyloxy or alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, preferably unfluorinated alkyl or alkenyl
  • L 91 denotes R 91 or X 91
  • L 92 denotes R 92 or X 92
  • R 91 and R 92 independently of one another, denote H, unfluorinated alkyl or alkoxy having 1 to 15,
  • the compounds of the formula V-2 are preferably selected from the group of the compounds of the formulae V-2a to V-2e and/or from the group of the compounds of the formulae V-2f and V-2g:
  • the compounds of the formula V-3 are preferably compounds of the formula V-3a: in which the parameters have the respective meanings indicated above for formula V-1 and in which preferably X 51 denotes F, Cl, preferably F, X 52 denotes F, Cl or -OCF 3 , preferably -OCF 3 .
  • the compounds of the formula V-1a are preferably selected from the group of the compounds of the formulae V-1a-1 and V-1a-2: in which R 51 has the meaning indicated above and preferably denotes C n H 2n+1 , in which n denotes an integer in the range from 1 to 7, preferably in the range from 1 to 6 and particularly preferably 3 to 5.
  • the compounds of the formula V-1b are preferably compounds of the formula V-1b-1: in which R 51 has the meaning indicated above and preferably denotes C n H 2n+1 , in which n denotes an integer in the range from 1 to 7, preferably in the range from 1 to 6 and particularly preferably 3 to 5.
  • the compounds of the formula V-1c are preferably selected from the group of the compounds of the formulae V-1c-1 to V-1c-4, particularly preferably selected from the group of the compounds of the formulae V-1c-1 and V-1c-2: in which R 51 has the meaning indicated above and preferably denotes C n H 2n+1 , in which n denotes an integer in the range from 1 to 7, preferably in the range from 1 to 6 and particularly preferably 3 to 5.
  • the compounds of the formula V-1d are preferably selected from the group of the compounds of the formulae V-1d-1 and V-1d-2, particularly preferably the compound of the formula V-1d-2: 1 2 in which R 51 has the meaning indicated above and preferably denotes C n H 2n+1 , in which n denotes an integer in the range from 1 to 7, preferably in the range from 1 to 6 and particularly preferably 3 to 5.
  • n and m independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 1 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.
  • (R 51 and R 52 ) here is, in particular, (C n H 2n+1 and O-C m H 2m+1 ).
  • the preferred combinations of (R 51 and R 52 ) here are, in particular, (C n H 2n+1 and C m H 2m+1 ) and (C n H 2n+1 and O-C m H 2m+1 ), particularly preferably (C n H 2n+1 and C m H 2m+1 ).
  • the preferred combinations of (R 51 and R 52 ) here are, in particular, (C n H 2n+1 and C m H 2m+1 ) and (C n H 2n+1 and O-C m H 2m+1 ), particularly preferably (C n H 2n+1 and O-C m H 2m+1 ).
  • the compounds of the formula VI-1 are preferably selected from the group of the compounds of the formulae VI-1a and VI-1b, more preferably selected from compounds of the formula VI-1a:
  • n and m independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.
  • the preferred combinations of (R 61 and R 62 ) here are, in particular, (C n H 2n+1 and C m H 2m+1 ) and (C n H 2n+1 and O-C m H 2m+1 ), in the case of formula VI-1a particularly preferably (C n H 2n+1 and C m H 2m+1 ) and in the case of formula VI-1b particularly preferably (C n H 2n+1 and O-C m H 2m+1 ).
  • the compounds of the formula VI-3 are preferably selected from the compounds of the formula VI-3a to VI-3e:
  • R 61 has the meaning indicated above and preferably denotes C n H 2n+1 , in which n denotes an integer in the range from 1 to 7, preferably in the range from 1 to 5, and X 62 denotes -F, -Cl, -OCF 3 , or -CN.
  • the compounds of the formula VI-4 are preferably selected from compounds of the for- mulae VI-4a to VI-4e:
  • R 61 has the meaning indicated above and preferably denotes C n H 2n+1 , in which n denotes an integer in the range from 1 to 7, preferably in the range from 1 to 5, and X 62 denotes F, Cl, OCF 3 , or -CN.
  • the compounds of the formula VI-5 are preferably selected from the compounds of the formulae VI-5a to VI-5d, preferably VI-5b:
  • R 61 has the meaning indicated above and preferably denotes C n H 2n+1 , in which n denotes an integer in the range from 1 to 7, preferably in the range from 1 to 5, and X 62 denotes -F, -Cl, -OCF 3 , or -CN, particularly preferably -OCF 3 .
  • the compounds of the formula VII are preferably selected from the group of the compounds of the formulae VII-1 to VII-6:
  • R 71 denotes unfluorinated alkyl or alkoxy, each having 1 to 7 C atoms, or unfluorinated alkenyl having 2 to 7 C atoms
  • R 72 denotes unfluorinated alkyl or alkoxy, each having 1 to 7 C atoms, or unfluorinated alkenyl having 2 to 7 C atoms
  • R 72 has the meaning indicated above and preferably denotes C m H 2m+1 or O-C m H 2m
  • the compounds of the formula VII-1 are preferably selected from the group of the compounds of the formulae VII-1a to VII-1d: in which X 72 has the meaning given above for formula VII-2 and R 71 has the meaning indicated above and preferably denotes C n H 2n+1 , in which n denotes an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2, and X 72 preferably denotes F.
  • the preferred combinations of (R 71 and R 72 ) here are, in particular, (C n H 2n+1 and C m H 2m+1 ) and (C n H 2n+1 and O-C m H 2m+1 ), particularly preferably (C n H 2n+1 and C m H 2m+1 ).
  • the preferred combinations of (R 71 and R 72 ) here are, in particular, (C n H 2n+1 and C m H 2m+1 ) and (C n H 2n+1 and O-C m H 2m+1 ), particularly preferably (C n H 2n+1 and C m H 2m+1 ).
  • the preferred combinations of (R 71 and R 72 ) here are, in particular, (C n H 2n+1 and C m H 2m+1 ) and (C n H 2n+1 and O-C m H 2m+1 ), particularly preferably (C n H 2n+1 and C m H 2m+1 ).
  • the preferred combinations of (R 71 and R 72 ) here are, in particular, (C n H 2n+1 and C m H 2m+1 ) and (C n H 2n+1 and O-C m H 2m+1 ), particularly preferably (C n H 2n+1 and C m H 2m+1 ).
  • the preferred combinations of (R 71 and R 72 ) here are, in particular, (C n H 2n+1 and C m H 2m+1 ) and (C n H 2n+1 and O-C m H 2m+1 ), particularly preferably (C n H 2n+1 and C m H 2m+1 ).
  • the preferred combinations of (R 81 and R 82 ) here are, in particular, (C n H 2n+1 and C m H 2m+1 ) and (C n H 2n+1 and O-C m H 2m+1 ), particularly preferably (C n H 2n+1 and C m H 2m+1 ).
  • the preferred combinations of (R 81 and R 82 ) here are, in particular, (C n H 2n+1 and C m H 2m+1 ) and (C n H 2n+1 and O-C m H 2m+1 ), particularly preferably (C n H 2n+1 and C m H 2m+1 ).
  • the preferred combinations of (R 81 and R 82 ) here are, in particular, (C n H 2n+1 and C m H 2m+1 ) and (C n H 2n+1 and O-C m H 2m+1 ).
  • the compounds of the formula IX are preferably selected from the group of the compounds of the formulae IX-1 to IX-3:
  • n and m independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.
  • the preferred combinations of (R 91 and R 92 ) here are, in particular, (C n H 2n+1 and C m H 2m+1 ) and (C n H 2n+1 and O-C m H 2m+1 ).
  • the compounds of the formula IX-1 are preferably selected from the group of the compounds of the formulae IX-1a to IX-1e: in which the parameters have the meaning given above and preferably R 91 has the meaning indicated above and preferably denotes C n H 2n+1 , and n denotes an integer in the range from 0 to 15, preferably in the range from 1 to 7 and particularly preferably 1 to 5, and X 92 preferably denotes F or Cl.
  • the compounds of the formula IX-2 are preferably selected from the group of the compounds of the formulae IX-2a and IX-2b:
  • n and m independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.
  • the preferred combination of (R 91 and R 92 ) here is, in particular, (C n H 2n+1 and C m H 2m+1 ).
  • the preferred combinations of (R 91 and R 92 ) here are, in particular, (C n H 2n+1 and C m H 2m+1 ) and (C n H 2n+1 and O-C m H 2m+1 ), particularly preferably (C n H 2n+1 and O-C m H 2m+1 ).
  • the medium comprises one or more compounds of formula X in which R 101 denotes H, alkyl or alkoxy having 1 to 15, preferably 2 to 10, C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, preferably alkyl or alkenyl, X 101 denotes H, F, Cl, -CN, SF 5 , NCS, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, fluorinated alkenyloxy or fluorinated alkoxyalkyl having 2 to 7 C atoms, preferably fluorinated alkoxy, fluorinated alkenyloxy, F, Cl or NCS, particularly preferably NCS, Y 101 denotes methyl, ethyl or Cl, Y 102 denotes H, methyl,
  • the compounds of formula X are selected from the sub-formulae X-1 and X-2 in which the occurring groups and parameters have the meanings given above for formula X.
  • the media according to the invention comprise one or more compounds selected from the group of compounds of the formulae X-1-1 to X-1-9 In which R 101 denotes alkyl having 1 to 7 C atoms.
  • the medium according to the invention comprises one or more compounds of formula XI I in which R S denotes H, alkyl or alkoxy having 1 to 12 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 12 C atoms, in which one or more CH 2 -groups may be replaced by , , , and in which one or more H atoms may be replaced by F, d , on each occurrence, independently of one another, denote , in which R L , on each occurrence identically or differently, denotes H, Cl or straight-chain, branched or cyclic alkyl having 1 to 6 C atoms, L S1 , L S2 identically or differently, denote H, Cl or F, R S1 , R S2 , identically or differently, denote H, alkyl or alkenyl, having up to 6 C atoms, or cyclopropyl, cyclobutyl, cyclopentenyl,
  • the compounds of formula XI are selected from the group of compounds of the formulae XI-1 to XI-24: in which the occurring groups have the meanings given above for formula XI and preferably R S denotes alkyl or alkenyl having 2 to 6 C atoms, in which one or more CH 2 -groups may be replaced by R S1 and R S2 identically or differently, denote H or alkyl having 1 to 6 C atoms, preferably H, R S3 denotes H, F or alkyl, having up to 6 C atoms, or cyclopropyl, preferably H, F or ethyl, very preferably H, L S1 and L S2 identically or differently, denote H or F, preferably F.
  • R S denotes alkyl or alkenyl having 2 to 6 C atoms, in which one or more CH 2 -groups may be replaced by R S1 and R S2 identically or differently, denote H or alkyl having 1 to 6 C atoms,
  • the medium comprises a compound of formula XII-3, in which the occurring groups have the meanings given above and particularly preferably L 1 denotes H, X 1 , X 2 , X 3 and X 4 denote F and R 12 denotes alkyl having 1 to 7 C atoms.
  • R 13 denotes alkyl having 1 to 7 C atoms, Y 1 , Y 2 , Y 3 , and Y 4 , identically or differently, denote H, F, Cl, methyl, ethyl, n-propyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclopentenyl, and more preferably Y 1 and Y 2 independently denote H or F, in particular H, and Y 3 and Y 4 very preferably denote H, and L 1 and L 2 , identically or differently, very preferably denote H, F, methyl or ethyl, in particular H.
  • the liquid crystalline media according to the invention comprise one or more compounds selected from the group of compounds of the formulae T-1a to T-3b below:
  • the media comprise one or more compounds selected from the compounds of the formulae T-1a and T-2a.
  • Preferred compounds of formula T-1a are selected from the group of compounds of the following sub-formulae:
  • n 1, 2, 3 or 4, preferably 1.
  • Preferred compounds of formula T-2a are selected from the group of compounds of the following sub-formulae:
  • n 1, 2, 3 or 4, preferably 1.
  • Preferred compounds of formula T-3a are selected from the group of compounds of the following sub-formulae:
  • the medium according to the invention comprises one or more compounds of formula T-1a-5.
  • the medium according to the invention comprises one or more compounds of formula I, II, III, IV, V, VI, VII, VIII, IX, X in which the radical R 1 , R 2 , R 3 , R 41 , R 42 , R 51 , R 52 , R 61 , R 62 , R 71 , R 72 , R 81 , R 82 , R 91 , R 92 , R 101 , R 102 and R S , respectively, is a cyclic alkyl group.
  • Very preferred compounds comprising a cyclic alkyl group are selected from the compounds of the formulae Cy-1 to Cy-14
  • the compound of formula N is preferably selected from the group consisting of the formulae N-1, N-2 and N-3: in which R N , Z N1 , Z N2 , X 1 , X 2 and n, have the respective meanings given above for formula N.
  • R N , Z N1 , Z N2 , X 1 , X 2 and n have the respective meanings given above for formula N.
  • R L on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, preferably H, methyl or ethyl, particularly preferably H
  • L denotes F or alkyl having 1 to 6 C atoms
  • r is 0, 1, 2, 3, 4, 5 or 6, preferably 0 or 1
  • the radicals X 1 and X 2 both denote H.
  • the radical X 1 denotes H and the radical X 2 denotes F or Cl.
  • the radical X 1 denotes F or Cl and the radical X 2 denotes H.
  • the radicals X 1 and X 2 denote F or Cl, preferably both F.
  • the compounds of the formulae N-1, N-2 and N-3 are preferably selected from the group consisting of the formulae N-1-1 to N-1-10, N-2-1 to N-2-10 and N-3-1 to N-3-10:
  • the medium according to the invention comprises a compound of formula NI I in which R N , , Z N1 , Z N2 , W, X 1 , X 2 and n, have the respective meanings given in claim 1 for formula N.
  • the compounds of formula NI are preferably selected from the compounds of the formulae NI-1 and NI-2 in which R N , Z N1 , Z N2 , have the meanings given above for formula N, Y 1 and Y 2 , identically or differently, denote H, F or Cl, and t is 0 or 1.
  • R N , Z N1 , Z N2 have the meanings given above for formula N, Y 1 and Y 2 , identically or differently, denote H, F or Cl, and t is 0 or 1.
  • R N , Z N1 , Z N2 have the meanings given above for formula N, Y 1 and Y 2 , identically or differently, denote H, F or Cl, and t is 0 or 1.
  • R N , Z N1 , Z N2 have the meanings given above for formula N, Y 1 and Y 2 , identically or differently, denote H, F or Cl, and t is 0 or 1.
  • L 1 and L 2 identically or differently,
  • the compounds of formula NI-1 and NI-2 are selected from the compounds of the formulae NI-1-1 to NI-1-12 and NI-2- 1 to NI-2-12
  • L 1 , L 2 and L 3 identically or differently, denote H, F, Cl, methyl, ethyl, n-propyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclopentenyl, and R N , Y 1 and Y 2 have the meanings given above for formula N-1 and N-2, and in which very preferably the group denotes
  • one or both of Y 1 and Y 2 denote H, preferably both.
  • both of Y 1 and Y 2 denote F.
  • the compounds of formula UI are preferably selected from the group of compounds consisting of the formulae UI-1, UI-2 and UI-3: in which R U U1 U2 , X and X have the meanings given above for formula UI, and where in formula UI-3 at least one of and denotes trans-1,4-cyclohexylene, 1,4-cyclohexenylene, tetralin-2,6-diyl, tetralin-5,8-diyl, decalin-2,6-diyl, bicyclo[1.1.1]pentane-1,3-diyl, 4,4 ⁇ -bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl, or spiro[3.3]heptane-2,6-diyl, in which one or two CH groups may be replaced by N, one or more non-adjacent CH 2 groups may be replaced by -O- and/or -S- and in
  • R U has the meanings given above and preferably denotes straight chain or branched alkyl having 1 to 7 C atoms, in particular methyl, ethyl, n-propyl, n-butyl, n- pentyl, n-hexyl or n-heptyl.
  • the medium preferably comprises one or more compounds of the formula UI and one or more compounds of the formula UII.
  • the compounds of the formula UII are selected from the compounds of the formulae UII-1, UII-2 and UII-3, preferably UII-1 and UII-2, in particular UII-1: in which the occurring groups have the meanings given above for formula UII and preferably , identically or differently, denote
  • X U1 and X U2 denote F
  • R U preferably denotes straight chain or branched or cyclic alkyl or alkenyl having 1 to 7 C atoms, or fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms.
  • Very preferred compounds of formula UII are selected from the following sub-formulae: in which R U has the meanings given above and preferably denotes straight chain or branched alkyl having 1 to 7 C atoms, in particular methyl, ethyl, n-propyl, n-butyl, n- pentyl, n-hexyl or n-heptyl.
  • the medium according to the invention preferably comprises one or more compounds of the formulae GF-1-1 to GF-5-1:
  • R G denotes straight chain or branched alkyl having 1 to 7 C atoms, in particular methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl or 2-methylbut-1-yl.
  • the media according to the present invention comprise one or more chiral dopants.
  • these chiral dopants have an absolute value of the helical twisting power (HTP) in the range of from 1 ⁇ m -1 to 150 ⁇ m -1 , preferably in the range of from 10 ⁇ m -1 to 100 ⁇ m -1 .
  • HTP helical twisting power
  • the media comprise two or more chiral dopants, these may have opposite signs of their HTP-values. This condition is preferred for some specific embodiments, as it allows to compensate the chirality of the respective compounds to some degree and, thus, may be used to compensate various temperature dependent properties of the resulting media in the devices. Generally, however, it is preferred that most, preferably all of the chiral compounds present in the media according to the present invention have the same sign of their HTP-values.
  • the chiral dopants present in the media according to the instant application are mesogenic compounds and most preferably they exhibit a mesophase on their own.
  • the medium comprises two or more chiral compounds which all have the same algebraic sign of the HTP.
  • the temperature dependence of the HTP of the individual compounds may be high or low.
  • the temperature dependence of the pitch of the medium can be compensated by mixing compounds having different temperature dependencies of the HTP in corresponding ratios.
  • chiral dopants some of which are commercially available, is available to the person skilled in the art, such as, for example, cholesteryl nonanoate, R- and S-811, R- and S-1011, R- and S-2011, R- and S-3011, R- and S-4011, or CB15 (all Merck KGaA, Darmstadt).
  • Particularly suitable dopants are compounds which contain one or more chiral groups and one or more mesogenic groups, or one or more aromatic or alicyclic groups which form a mesogenic group with the chiral group.
  • Suitable chiral groups are, for example, chiral branched hydrocarbon radicals, chiral ethane diols, binaphthols or dioxolanes, furthermore mono- or polyvalent chiral groups selected from the group consisting of sugar derivatives, sugar alcohols, sugar acids, lactic acids, chiral substituted glycols, steroid derivatives, terpene derivatives, amino acids or sequences of a few, preferably 1-5, amino acids.
  • Preferred chiral groups are sugar derivatives, such as glucose, mannose, galactose, fructose, arabinose and dextrose; sugar alcohols, such as, for example, sorbitol, mannitol, iditol, galactitol or anhydro derivatives thereof, in particular dianhydrohexitols, such as dianhydrosorbide (1,4:3,6-dianhydro-D-sorbide, isosorbide), dianhydromannitol (isosorbitol) or dianhydroiditol (isoiditol); sugar acids, such as, for example, gluconic acid, gulonic acid and ketogulonic acid; chiral substituted glycol radicals, such as, for example, mono- or oligoethylene or propylene glycols, in which one or more CH 2 groups are substituted by alkyl or alkoxy; amino acids, such as, for example, alanine, valine, phenyl
  • the media according to the present invention preferably comprise chiral dopants which are selected from the group of known chiral dopants. Suitable chiral groups and mesogenic chiral compounds are described, for example, in DE 3425503, DE 3534777, DE 3534778, DE 3534779 and DE 3534780, DE 4342280, EP 01038941 and DE 19541820. Examples are also compounds listed in Table F below. Chiral compounds preferably used according to the present invention are selected from the group consisting of the formulae shown below.
  • a 22 has the meanings given for A 12
  • a 31 has the meanings given for A 11
  • a 32 has the meanings given for A 12
  • n2 on each occurrence, identically or differently is 0, 1 or 2
  • n3 is 1, 2 or 3
  • r is 0, 1, 2, 3 or 4.
  • dopants selected from the group consisting of the compounds of the following formulae: in which m is, on each occurrence, identically or differently, an integer from 1 to 9 and n is, on each occurrence, identically or differently, an integer from 2 to 9.
  • Particularly preferred compounds of formula A are compounds of formula A-III.
  • dopants are derivatives of the isosorbide, isomannitol or isoiditol of the following formula A-IV: preferably dianhydrosorbitol, and chiral ethane diols, such as, for example, diphenylethanediol (hydrobenzoin), in particular mesogenic hydrobenzoin derivatives of the following formula A-V: including the (S,S) enantiomers, which are not shown, in which are each, independently of one another, 1,4-phenylene, which may also be mono-, di- or trisubstituted by L, or 1,4-cyclo- hexylene, L is H, F, Cl, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl or alkoxycarbonyloxy having 1-7 carbon atoms, c is 0 or 1, X is CH 2 or -C(O)-, Z 0 is -COO-,
  • the compounds of the formula A-IV are described in WO 98/00428.
  • the compounds of the formula A-V are described in GB-A-2,328,207.
  • Very particularly preferred dopants are chiral binaphthyl derivatives, as described in WO 02/94805, chiral binaphthol acetal derivatives, as described in WO 02/34739, chiral TADDOL derivatives, as described in WO 02/06265, and chiral dopants having at least one fluorinated bridging group and a terminal or central chiral group, as described in WO 02/06196 and WO 02/06195.
  • chiral binaphthyl derivatives of the formula A-VI-1 in which ring B, R 0 and Z 0 are as defined for the formulae A-IV and A-V, and b is 0, 1, or 2, in particular those selected from the following formulae A-VI-1a to A-VI-1c: in which ring B, R 0, and Z 0 are as defined for the formula A-VI-1, and R 0 as defined for formula A-IV or H or alkyl having from 1 to 4 carbon atoms, and b is 0, 1 or 2, and Z 0 is, in particular, -OC(O)- or a single bond.
  • the concentration of the one or more chiral dopant(s), in the LC medium is preferably in the range from 0.001 % to 20 %, preferably from 0.05 % to 5 %, more preferably from 0.1 % to 2 %, and, most preferably from 0.5 % to 1.5 %.
  • concentration ranges apply in particular to the chiral dopant S-4011 or R-4011 (both from Merck KGaA) and for chiral dopants having the same or a similar HTP.
  • S-4011 or R-4011 both from Merck KGaA
  • these preferred concentrations have to be decreased, respectively increased proportionally according to the ratio of their HTP values relatively to that of S-4011.
  • the pitch p of the LC media or host mixtures according to the invention is preferably in the range of from 5 to 50 ⁇ m, more preferably from 8 to 30 ⁇ m and particularly preferably from 10 to 20 ⁇ m.
  • the media according to the invention comprise a stabiliser selected from the group of compounds of the formulae ST-1 to ST-22.
  • n preferably denotes 3.
  • n preferably denotes 7.
  • Very particularly preferred mixtures according to the invention comprise one or more stabilisers from the group of the compounds of the formulae ST-2a-1, ST-3a-1, ST-3b-1, ST-8-1, ST-9-1 and ST-12:
  • the compounds of the formulae ST-1 to ST-12 are preferably each present in the liquid-crystal mixtures according to the invention in amounts of 0.005 – 0.5%, based on the mixture, very preferably in an amount of 100 ppm, 250 ppm, 500 ppm or 1000 ppm. If the mixtures according to the invention comprise two or more compounds from the group of the compounds of the formulae ST-1 to ST-18, the concentration correspondingly increases to 0.01 – 1% in the case of two compounds, based on the mixtures. However, the total proportion of the compounds of the formulae ST-1 to ST-18, based on the mixture according to the invention, should not exceed 2%.
  • the medium comprises one or more compounds of formula D in a total concentration of 1 % to 20 %, more preferably 5 % to 15 %, particularly preferably 8 % to 12 %.
  • the liquid-crystalline media comprise a compound of formula T, preferably in a total concentration in the range of from 5 % to 35 %, more preferably 6 % to 30 % and particularly preferably 7 % to 25 %, preferably selected from the formulae T-1a, T-2a and T-3a, very preferably selected from T-1a-5, T-2a-2, T-2a-4 and T-3a-2.
  • the medium comprises one or more compounds of formula I, preferably of formula I-2 or I-3, in a total concentration in the range of from 1 % to 30 %, more preferably from 2 % to 25 %, very preferably 3% to 20% and particularly preferably from 5 % to 15 %.
  • the medium comprises one or more compounds selected from the compounds of the formulae II and GF-1-3 and UI-1-3, preferably of formula II-1 and/or UI-1-3, in a total concentration of 2 % to 35 %, more preferably 3 % to 30 %, particularly preferably 5 % to 25 %.
  • the medium comprises one or more compounds of formula IIA-1 in a total concentration of 5 % to 25 %, more preferably 8 % to 20 %, particularly preferably 12 % to 17 %.
  • the medium comprises one or more compounds of formula II-1 in an total concentration of 30% or less, more preferably 25% or less, particularly preferably 22% or less.
  • the medium comprises one or more compounds selected from the formulae III and IIIa-1 to IIIa-4, preferably III-1 and/or III- 2 and/or IIIa-2 and/or IIIa-3, more preferably III-1f and/or III-1b, and/or III-1h and/or IIIa- 2, in a total concentration of 15 % to 60 % or 65% or 70%, more preferably 20 % to 58 %, particularly preferably 30% to 55% or 35 % to 53 %.
  • the medium comprises one or more compounds of formula XII, preferably in a total concentration of 5 % to 30 %, more preferably 8 % to 25 %, particularly preferably 10 % to 20 %.
  • the medium comprises one or more compounds of the formula D and one or more compounds selected from the group consisting of the formulae I, II and/or IIA, III, XII, T, preferably in a total concentration of 90% or more, more preferably 95%, 96% or 97% or more, very preferably 98% or more and in particular 99% or more.
  • the medium comprises one or more compounds of the formula D and one or more compounds selected from the group consisting of the formulae I, II and/or IIA, III, XII, T in a total concentration in the range of from 40% to 90% and a total concentration of 10% or more of one or more compounds of the formula IV.
  • the medium comprises one or more compounds of the formula D and one or more compounds selected from the group consisting of the formulae I, II and/or IIA, III, XII and T in a total concentration in the range of from 40% to 70% and a total concentration of 30% or more of one or more compounds of the formula IV.
  • the medium comprises one or more compounds of the formula D and one or more compounds selected from the group consisting of the formulae I, II and/or IIA, III, XII and T in a total concentration in the range of from 40% to 60% and a total concentration of 40% or more of one or more compounds of the formula IV.
  • the medium comprises one or more compounds of formula XII-3, preferably of the formula CPU(F.F)-n-S, preferably in a concentration in the range of from 10 to 30%, in articular from 15% to 25%; -
  • the medium comprises one, two, three, four or more compounds of formula III-1, preferably selected from the compounds of the formulae III-1b, III-1f and III-1h; more preferably of III-1b and III-1h; -
  • the medium comprises a compound of formula III-1b, preferably in a total concentration in the range of from 5% to 40%, more preferably 10% to 35%, in particular 15% to 30%; -
  • the medium comprises a compound of formula III-1h, preferably in a total concentration in the range of from 7% to 35%, more preferably 10% to
  • the liquid-crystal media in accordance with the present invention preferably have a clearing point of 90°C or more, more preferably 100°C or more, more preferably 110°C or more, more preferably 120°C or more, more preferably 130°C or more, particularly preferably 140°C or more and very particularly preferably 150°C or more.
  • the nematic phase of the media according to the invention preferably extends at least from 0°C or less to 90°C or more.
  • the media according to the invention is advantageous for the media according to the invention to exhibit even broader nematic phase ranges, preferably at least from -10°C or less to 120°C or more, very preferably at least from -20°C or less to 140°C or more and in particular at least from -30°C or less to 150°C or more, very particularly preferably at least from -40°C or less to 170°C or more.
  • the ⁇ ⁇ of the liquid-crystal medium according to the present invention, at 1 kHz and 20°C, is preferably 5 or more, more preferably 7 or more and very preferably 8 or more.
  • the birefringence ( ⁇ n) of the liquid-crystal media according to the present invention, at 589 nm (Na D ) and 20°C, is preferably 0.280 or more, more preferably 0.300 or more, even more preferably 0.320 or more, very preferably 0.330 or more and in particular 0.350 or more.
  • the ⁇ n of the liquid-crystal media according to the present invention, at 589 nm (Na D ) and 20°C is preferably in the range from 0.200 to 0.900, more preferably in the range from 0.250 to 0.800, even more preferably in the range from 0.300 to 0.700 and very particularly preferably in the range from 0.350 to 0.600.
  • the ⁇ n of the liquid-crystal media in accordance with the present invention is preferably 0.50 or more, more preferably 0.55 or more.
  • the compounds of the formulae I to III in each case include dielectrically positive compounds having a dielectric anisotropy of greater than 3, dielectrically neutral compounds having a dielectric anisotropy of less than 3 and greater than -1.5 and dielectrically negative compounds having a dielectric anisotropy of -1.5 or less.
  • the compounds of the formulae D, I, II and III are preferably dielectrically positive.
  • the optical component according to the invention is designed and configured as an optical phase modulator.
  • the optical component according to the invention is designed and configured for use in a transparent device for phase modulation of IR radiation.
  • the optical component according to the invention is designed and configured for use in a reflective device for phase modulation of IR radiation.
  • a typical electro-optical modulator comprises conducting, infrared transmitting windows consisting for example of Ge, separated from one another by spacers and having a cell gap in the range of from 1 mm to 5 mm.
  • a LIDAR scanning system as described in WO2018/156643 A1, including a laser configured to emit pulses of light at an operating wavelength in the infrared.
  • the LIDAR scanning system includes a transmit reconfigurable-metasurface configured to reflect an incident pulse of light from the laser as an illumination beam pointing at a selected portion of a field of view, preferably a two dimensional field of view.
  • the pointing of the illumination beam is responsive to a first selected holographic beam steering pattern implemented in the transmit reconfigurable-metasurface.
  • the system further includes a receive reconfigurable-metasurface configured to reflect a return of the illumination beam from the selected portion of the field of view as a relay beam pointing at an optical detector.
  • the pointing of the relay beam is responsive to a second selected holographic beam steering pattern implemented in the receiving reconfigurable metasurface.
  • the system includes an optical detector comprising an array of detector pixels.
  • Each detector pixel includes (i) a photodetector configured to detect light in the return of the illumination beam and (ii) a timing circuit configured to determine a time of flight of the detected light.
  • the optical detector is also configured to output a detection signal indicative of the detected light and a time of flight of the detected light for each pixel of the array.
  • the transmit reconfigurable-metasurface includes a plurality of dynamically adjustable high-Q dielectric resonators arranged on a surface of the reconfigurable-metasurface with inter-element spacing less than the operating wavelength of the laser, where the surface of the reconfigurable-metasurface includes a conducting surface, and the plurality of resonators have a corresponding plurality of adjustable reflection phases providing a dynamically adjustable reflected wave responsive to an incident wave, wherein the conducting surface and the plurality of resonators define a metasurface.
  • Each of the plurality of dielectric resonators includes (i) a pair of regions having high refractive index; and (ii) an electrically-adjustable material disposed in a gap between the regions, wherein the electrically-adjustable material is a liquid crystal material as set forth above and below.
  • a reflective spatial light modulator in particular an LCoS device including the liquid crystal material according to the invention, sandwiched between a transparent glass layer having a transparent electrode, a mirror mounted on a silicon CMOS backplane and PCB. The mirror is divided into a two-dimensional array of individually addressable pixels.
  • Each pixel is individually drivable by a voltage signal to provide a local phase change to at least one polarization component of an optical signal, thereby providing a two-dimensional array of phase manipulating regions.
  • Pre-alignment of the liquid crystal is provided by alignment layers.
  • Said LCoS device is useful for the integration into optical devices. Preferred devices are a wavelength selective switch (WSS), LIDAR scanner, infrared scene projector, as well as other beam steering applications as shown in the article Micallef, F. (2019). Middle infrared beam-steering using liquid crystals for spatial light modulation (Doctoral thesis). https://doi.org/10.17863/CAM.39602 (https://www.repository.cam.ac.uk/handle/1810/292443).
  • dielectrically positive describes compounds or components where ⁇ ⁇ > 3.0
  • dielectrically neutral describes those where -1.5 ⁇ ⁇ ⁇ ⁇ 3.0
  • dielectrically negative describes those where ⁇ ⁇ ⁇ -1.5.
  • ⁇ ⁇ is determined at a frequency of 1 kHz and at 20°C.
  • the dielectric anisotropy of the respective compound is determined from the results of a solution of 10 % of the respective individual compound in a nematic host mixture. If the solubility of the respective compound in the host mixture is less than 10 %, the concentration is reduced to 5 %.
  • the capacitances of the test mixtures are determined both in a cell having homeotropic alignment and in a cell having homogeneous alignment.
  • the cell thickness of both types of cells is approximately 20 ⁇ m.
  • the voltage applied is a rectangular wave having a frequency of 1 kHz and an effective value of typically 0.5 V to 1.0 V, but it is always selected to be below the capacitive threshold of the respective test mixture.
  • ⁇ ⁇ is defined as
  • the host mixture used for the determination of physical constants of pure compounds by extrapolation is ZLI-4792 from Merck KGaA, Germany.
  • the absolute values of the dielectric constants, the birefringence ( ⁇ n) and the rotational viscosity ( ⁇ 1 ) of the compounds are determined from the change in the respective values of the host mixture on addition of the compounds.
  • the concentration in the host is 10 % or in case of insufficient solubility 5 %.
  • the values are extrapolated to a concentration of 100 % of the added compounds.
  • the phase sequences of pure compounds are given using the following abbreviations: K: crystalline, N: nematic, SmA: smectic A, SmB: smectic B, I: isotropic. Components having a nematic phase at the measurement temperature of 20°C are measured as such, all others are treated like compounds.
  • the expression threshold voltage in the present application refers to the optical threshold and is quoted for 10 % relative contrast (V 10 ), and the expression saturation voltage refers to the optical saturation and is quoted for 90 % relative contrast (V 90 ), in both cases unless expressly stated otherwise.
  • V 0 The capacitive threshold voltage
  • V Fr the Freedericks threshold
  • the parameter ranges indicated in this application all include the limit values, unless expressly stated otherwise.
  • the different upper and lower limit values indicated for various ranges of properties in combination with one another give rise to additional preferred ranges.
  • All concentrations are quoted in per cent by weight and relate to the respective mixture as a whole, all temperatures are quoted in degrees Celsius and all temperature differences are quoted in differential degrees.
  • the optical aniso- tropy ( ⁇ n) is determined at a wavelength of 589.3 nm.
  • the dielectric anisotropy ( ⁇ ⁇ ) is determined at a frequency of 1 kHz.
  • the threshold voltages, as well as all other electro- optical properties, are determined using test cells produced at Merck KGaA, Germany. The test cells for the determination of ⁇ ⁇ have a cell thickness of approximately 20 ⁇ m.
  • the electrode is a circular ITO electrode having an area of 1.13 cm 2 and a guard ring.
  • the orientation layers are SE-1211 from Nissan Chemicals, Japan, for homeotropic orientation ( ⁇ ) and polyimide AL-1054 from Japan Synthetic Rubber, Japan, for homogeneous orientation .
  • the capacitances are determined using a Solatron 1260 frequency response analyser using a sine wave with a voltage of 0.3 V rms .
  • the light used in the electro-optical measurements is white light.
  • a set-up using a commercially available DMS instrument from Autronic-Melchers, Germany, is used here.
  • the charac- teristic voltages have been determined under perpendicular observation.
  • the threshold (V 10 ), mid-grey (V 50 ) and saturation (V 90 ) voltages have been determined for 10 %, 50 % and 90 % relative contrast, respectively.
  • the liquid-crystalline media are investigated with respect to their properties in the microwave frequency range as described in A. Penirschke et al. “Cavity Perturbation Method for Characterization of Liquid Crystals up to 35 GHz”, 34 th European Microwave Conference – Amsterdam, pp.545-548. Compare in this respect also A. Gaebler et al.
  • the liquid crystal is introduced into a polytetrafluoroethylene (PTFE) or quartz capillary.
  • the capillary has an inner diameter of 0.5mm and an outer diameter of 0.78mm.
  • the effective length is 2.0 cm.
  • the filled capillary is introduced into the centre of the cylindrical cavity with a resonance frequency of 19 GHz. This cavity has a length of 11.5 mm and a radius of 6 mm.
  • the input signal (source) is then applied, and the frequency depending response of the cavity is recorded using a commercial vector network analyser (N5227A PNA Microwave Network Analyzer, Keysight Technologies Inc. USA. For other frequencies, the dimensions of the cavity are adapted correspond- ingly.
  • the change in the resonance frequency and the Q factor between the measurement with the capillary filled with the liquid crystal and the measurement without the capillary filled with the liquid crystal is used to determine the dielectric constant and the loss angle at the corresponding target frequency by means of equations 10 and 11 in the above-mentioned publication A. Penirschke et al., 34 th European Microwave Conference – Amsterdam, pp.545-548, as described therein.
  • the values for the components of the properties perpendicular and parallel to the director of the liquid crystal are obtained by alignment of the liquid crystal in a magnetic field.
  • the magnetic field of a permanent magnet is used.
  • the strength of the magnetic field is 0.35 tesla.
  • Preferred components are phase shifters, varactors, wireless and radio wave antenna arrays, matching circuit adaptive filters and others.
  • the term compounds is taken to mean both one compound and a plurality of compounds, unless expressly stated otherwise. All mixtures according to the invention are nematic.
  • the liquid-crystal media according to the invention preferably have nematic phases in preferred ranges given above.
  • the expression have a nematic phase here means on the one hand that no smectic phase and no crystallisation are observed at low temperatures at the corresponding temperature and on the other hand that no clearing occurs on heating from the nematic phase.
  • the clearing point is measured in capillaries by con- ventional methods.
  • the investigation at low temperatures is carried out in a flow viscometer at the corresponding temperature and checked by storage of bulk samples:
  • the storage stability in the bulk (LTS) of the media according to the invention at a given temperature T is determined by visual inspection.2 g of the media of interest are filled into a closed glass vessel (bottle) of appropriate size placed in a refrigerator at a predetermined temperature.
  • the bottles are checked at defined time intervals for the occurrence of smectic phases or crystallisation. For every material and at each temperature two bottles are stored. If crystallisation or the appearance of a smectic phase is observed in at least one of the two correspondent bottles the test is terminated and the time of the last inspection before the one at which the occurrence of a higher ordered phase is observed is recorded as the respective storage stability. The test is finally terminated after 1000 h, i.e an LTS value of 1000 h means that the mixture is stable at the given temperature for at least 1000 h.
  • the liquid crystals employed preferably have a positive dielectric anisotropy. This is preferably 2 or more, preferably 4 or more, particularly preferably 6 or more and very particularly preferably 10 or more.
  • the liquid-crystal media according to the invention are characterised by high anisotropy values in the microwave range.
  • the birefringence at about 19 GHz is, for example, preferably 0.14 or more, particularly preferably 0.15 or more, particularly preferably 0.20 or more, particularly preferably 0.25 or more and very particularly preferably 0.30 or more.
  • the birefringence is preferably 0.80 or less.
  • the dielectric anisotropy in the microwave range is defined as
  • the tunability ( ⁇ ) is defined as
  • the material quality ( ⁇ ) is defined as , where the maximum dielectric loss is
  • the tunability ⁇ of the medium according to the invention, measured at 20°C and 19 GHz is 0.250 or more, preferably 0.300 or more, 0.310 or more, 0.320 or more, 0.330 or more, or 0.340 or more, very preferably 0.345 or more and in particular 0.350 or more.
  • the material quality ( ⁇ ) of the preferred liquid-crystal materials is 6 or more, preferably 8 or more, preferably 10 or more, preferably 15 or more, preferably 17 or more, preferably 20 or more, particularly preferably 25 or more and very particularly preferably 30 or more.
  • the preferred liquid-crystal materials have phase shifter qualities of 15°/dB or more, preferably 20°/dB or more, preferably 30°/dB or more, preferably 40°/dB or more, preferably 50°/dB or more, particularly preferably 80°/dB or more and very particularly preferably 100°/dB or more.
  • liquid crystals having a negative value of the dielectric anisotropy can also advantageously be used.
  • the liquid crystals employed are either individual substances or mixtures. They preferably have a nematic phase.
  • the liquid-crystal media in accordance with the present invention may comprise further additives and chiral dopants in the usual concentrations.
  • the total concentration of these further constituents is in the range from 0 % to 10 %, preferably 0.1 % to 6 %, based on the mixture as a whole.
  • the concentrations of the individual compounds used are each preferably in the range from 0.1 % to 3 %.
  • the concentration of these and similar additives is not taken into consideration when quoting the values and concen- tration ranges of the liquid-crystal components and liquid-crystal compounds of the liquid-crystal media in this application.
  • the media according to the present invention comprise one or more chiral compounds as chiral dopants in order to adjust their cholesteric pitch.
  • Their total concentration in the media according to the instant invention is preferably in the range 0.05 % to 15 %, more preferably from 1 % to 10 % and most preferably from 2 % to 6 %.
  • the media according to the present invention may comprise further liquid crystal compounds in order to adjust the physical properties. Such compounds are known to the skilled person.
  • Their concentration in the media according to the instant invention is preferably 0 % to 30 %, more preferably 0.1 % to 20 % and most preferably 1 % to 15 %.
  • the response times are given as rise time ( ⁇ on ) for the time for the change of the relative tuning, respectively of the relative contrast for the electro-optical response, from 0 % to 90 % (t 90 – t 0 ), i.e.
  • the liquid-crystal media according to the invention consist of a plurality of compounds, preferably 3 to 30, more preferably 4 to 20 and very preferably 4 to 16 compounds. These compounds are mixed in a conventional manner. In general, the desired amount of the compound used in the smaller amount is dissolved in the compound used in the larger amount.
  • the temperature is above the clearing point of the compound used in the higher concentration, it is particularly easy to observe completion of the dissolution process. It is, however, also possible to prepare the media in other conventional ways, for example using so-called pre-mixes, which can be, for example, homologous or eutectic mixtures of compounds, or using so-called “multibottle” systems, the constituents of which are themselves ready-to-use mixtures. All temperatures, such as, for example, the melting point T(C,N) or T(C,S), the transition from the smectic (S) to the nematic (N) phase T(S,N) and the clearing point T(N,I) of the liquid crystals, are quoted in degrees Celsius. All temperature differences are quoted in differential degrees.
  • Table B End groups Left-hand side Right-hand side Used alone -n- C n H 2n+1 - -n -C n H 2n+1 Used in combination with others -...K... in which n and m each denote integers, and the three dots “...” are placeholders for other abbreviations from this table.
  • Branched lateral groups are numbered starting from the position next to the ring (1) where the longest chain is selected, the smaller number indicating the length of the branch and the superscript number in brackets indicates the position of the branch, for example:
  • the following table shows illustrative structures together with their respective abbreviations. These are shown in order to illustrate the meaning of the rules for the abbreviations. They furthermore represent compounds which are preferably used.
  • Table C Illustrative structures
  • the following illustrative structures are examples as well as compounds, which are preferably additionally used in the media: in which m and n, identically or differently, are 1, 2, 3, 4, 5, 6 or 7.
  • the medium according to the invention comrises one or more compounds selected from the compounds of Table C.
  • Table D shows illustrative compounds which can be used as alternative stabilisers in the mesogenic media in accordance with the present invention. The total concentration of these and similar compounds in the media is preferably 5 % or less.
  • the mesogenic media comprise one or more compounds selected from the group of the compounds from Table D.
  • Table E shows illustrative compounds which can preferably be used as chiral dopants in the mesogenic media in accordance with the present invention.
  • the mesogenic media comprise one or more compounds selected from the group of the compounds of Table E.
  • the mesogenic media in accordance with the present application preferably comprise two or more, preferably four or more, compounds selected from the group consisting of the compounds from the above tables. Unless indicated otherwise, parts or per cent data denote parts by weight or per cent by weight.
  • V o denotes threshold voltage, capacitive [V] at 20°C, n e denotes extraordinary refractive index at 20°C and 589 nm, n o denotes ordinary refractive index at 20°C and 589 nm, ⁇ n denotes optical anisotropy at 20°C and 589 nm, denotes dielectric permittivity perpendicular to the director at 20°C and 1 kHz, denotes dielectric permittivity parallel to the director at 20°C and 1 kHz, ⁇ ⁇ denotes dielectric anisotropy at 20°C and 1 kHz, clp., T(N,I) denotes clearing point [°C], ⁇ 1 denotes rotational viscosity measured at 20°C [mPa ⁇ s], K 1 denotes elastic constant, "splay” deformation at 20°C [pN], K 2 denotes elastic constant, "twist” deformation at 20°C [pN],
  • LTS low-temperature stability (nematic phase), determined in test cells or in the bulk, as specified.
  • T(C,N) melting point
  • S smectic phase
  • T(N,I) or clp. clearing point
  • M.p. melting point
  • Tg glass state
  • C crystalline state
  • N nematic phase
  • S smectic phase
  • I isotropic phase. The numbers between these symbols represent the transition temperatures.
  • threshold voltage for the present invention relates to the capacitive threshold (V 0 ), also called the Freedericksz threshold, unless explicitly indicated otherwise.
  • the optical threshold can also be indicated for 10 % relative contrast (V 10 ).
  • the display used for measurement of the capacitive threshold voltage consists of two plane-parallel glass outer plates at a separation of 20 ⁇ m, which each have on the insides an electrode layer and an unrubbed polyimide alignment layer on top, which cause a homeotropic edge alignment of the liquid-crystal molecules.
  • the so-called “HTP” denotes the helical twisting power of an optically active or chiral substance in an LC medium (in ⁇ m).
  • the HTP is measured in the commercially available nematic LC host mixture MLD-6260 (Merck KGaA) at a temperature of 20°C.
  • the Clearing point is measured using the Mettler Thermosystem FP900.
  • the optical anisotropy ( ⁇ n) is measured using an Abbe Refractometer H005 (Natrium-spectral lamp Na10 at 589nm, 20 °C).
  • the dielectric anisotropy ( ⁇ ⁇ ) is measured using an LCR- Meter E4980A/Agilent (G005) at 20°C ( ⁇ -parallel-cells with JALS 2096-R1).
  • the turn on voltage (V 0 ) is measured using an LCR-Meter E4980A/Agilent (G005) at 20°C ( ⁇ - parallel-cells with JALS 2096-R1).
  • the rotational viscosity ( ⁇ 1 ) is measured using a TOYO LCM-2 (0002) at 20°C (gamma 1 negative cells with JALS-2096-R 1 ).
  • the elastic constant (K 1 , splay) is measured using an LCR-Meter E4980A/Agilent (G005) at 20°C ( ⁇ parallel-cells with JALS 2096-R1).
  • K 3 The elastic constant (K 3 , bend) is measured using an LCR-Meter E4980A/Agilent (G005) at 20°C ( ⁇ -parallel-cells with JALS 2096-R1). Unless explicitly noted otherwise, all concentrations in the present application are indicated in per cent by weight and relate to the corresponding mixture as a whole, comprising all solid or liquid-crystalline components, without solvents. All physical properties are determined in accordance with "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status November 1997, Merck KGaA, Germany, and apply for a temperature of 20°C, unless explicitly indicated otherwise. Examples The present invention is illustrated in detail by the following non-restrictive working examples.
  • Pentyl magnesium bromide 25 ml of a 2M solution in diethyl ether is added dropwise at -20°C, and the reaction mixture is stirred for 2 h at -20°C. It is then quenched with ice water (100 ml), acidified with hydrochloric acid (2N) and extracted with MTB ether twice. The combined organic phases are dried (sodium sulfate), filtered and concentrated in vacuo. The residue is purified by flash chromatography (silica gel, eluent heptane) followed by RP chromatography (eluent acetonitrile) to give 7-bromo-3- pentyl-1,2-dihydronaphthalene as a colorless oil. Step 1.2: 2,6-Difluoro-4-((6-pentyl-7,8-dihydronaphthalen-2-yl)ethynyl)aniline
  • Step 1.3 7-((3,5-Difluoro-4-isothiocyanatophenyl)ethynyl)-3-pentyl-1,2- dihydronaphthalene
  • Thiophosgene (0.9 ml, 11 mmol) is slowly added to a solution of 2,6-difluoro-4-((6- pentyl-7,8-dihydronaphthalen-2-yl)ethynyl)aniline (3.0 g, 9 mmol) and DABCO (3.0 g, 27 mmol) in dichloromethane (50 ml) at 0°C under argon atmosphere, and the reaction mixture is stirred at room temperature for 1 h.
  • Step 2.2 2,6-Difluoro-4-((6-(pent-1-yn-1-yl)-7,8-dihydronaphthalen-2-yl)ethynyl)aniline
  • 7-bromo-3-(pent-1-yn-1-yl)-1,2-dihydronaphthalene 5.6 g, 20 mmol
  • 4-ethynyl-2,6-difluoroaniline CAS 753501-37-0
  • XPhos Pd G2 32 mg, 0.04 mmol
  • copper(I) iodide 3.8 mg, 0.02 mmol
  • Step 2.3 7-((3,5-Difluoro-4-isothiocyanatophenyl)ethynyl)-3-(pent-1-yn-1-yl)-1,2- dihydronaphthalene
  • Thiophosgene (1.8 ml, 23 mmol) is slowly added to a solution of 2,6-difluoro-4-((6- (pent-1-yn-1-yl)-7,8-dihydronaphthalen-2-yl)ethynyl)aniline (5.8 g, 17 mmol) and DABCO (5.0 g, 45 mmol) in dichloromethane (80 ml) at 0°C under argon atmosphere, and the reaction mixture is stirred at room temperature overnight.
  • Step 3.2 2,6-Difluoro-4-(6-((4-pentylphenyl)ethynyl)-7,8-dihydronaphthalen-2-yl)aniline
  • a solution of potassium carbonate (2.9 g, 21 mmol) in dist. water (15 ml) is added to a solution of 7-bromo-3-((4-pentylphenyl)ethynyl)-1,2-dihydronaphthalene (4.7 g, 12 mmol) in THF (80 ml) at room temperature under argon atmosphere.
  • the aqueous phase is separated and washed with MTB- ether, and the combined organic phases are washed with brine, dried (sodium sulfate) and concentrated in vacuo.
  • the residue is purified by flash chromatography (silica gel, eluent heptane/chlorobutane) and crystallization (toluene) to give 2,6-difluoro-4-(6-((4- pentylphenyl)ethynyl)-7,8-dihydronaphthalen-2-yl)aniline as a pale yellow solid.
  • Step 3.3 7-(3,5-Difluoro-4-isothiocyanatophenyl)-3-((4-pentylphenyl)ethynyl)-1,2- dihydronaphthalene
  • Thiophosgene (0.9 ml, 11 mmol) is slowly added to a solution of 2,6-difluoro-4-(6-((4- pentylphenyl)ethynyl)-7,8-dihydronaphthalen-2-yl)aniline (3.7 g, 9 mmol) and DABCO (3.0 g, 27 mmol) in dichloromethane (50 ml) at 0°C under argon atmosphere, and the reaction mixture is stirred for 2 h at room temperature.
  • Step 4.2 2,6-Difluoro-4-((6-pentyl-3,4-dihydronaphthalen-2-yl)ethynyl)aniline
  • 4-((6-bromo-3,4-dihydronaphthalen-2-yl)ethynyl)-2,6-difluoroaniline 8. g, 23 mmol
  • potassium phosphate monohydrate 11.0 g, 45 mmol
  • bis(dibenzylidene-acetone)palladium(0) 130 mg, 0.22 mmol
  • 2- dicyclohexylphosphino-2’,6’-dimethoxybiphenyl 190 mg, 0.45 mmol
  • Step 4.3 3-((3,5-Difluoro-4-isothiocyanatophenyl)ethynyl)-7-pentyl-1,2- dihydronaphthalene
  • Thiophosgene (2.7 g, 23 mmol) is slowly added to a solution of 2,6-difluoro-4-((6- pentyl-3,4-dihydronaphthalen-2-yl)ethynyl)aniline (6.4 g, 18 mmol) and DABCO (5.2 g, 46 mmol) in dichloromethane (100 ml) at 0°C under argon atmosphere, and the reaction mixture is stirred at room temperature overnight. Then it is quenched with dist.
  • Host mixture H1 has the following composition: The following example mixtures are prepared from host mixture H1 and compounds according to the invention as indicated in the following tables. Comparative example C1 Example Mixture M1 Example Mixture M1 differs from the Comparative Example C1 in that the compound PTU-5-S has been replaced with the compound Np(2H)TU-5-S according to the invention. This has the effect that the clearing temperature, the dielectric loss, the tunability and the figure-of-merit are all significantly improved.
  • Example Mixture M2 Example Mixture M3
  • Example Mixture M4 Example Mixture M5
  • Example Mixture M6 Example Mixture M7

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Abstract

The present invention relates to a dihydronaphthalene derivative of formula D as specified in claim 1, to a liquid crystal medium comprising a compound of formula D and to high-frequency components comprising these media, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, tunable filters, tunable metamaterial structures, and electronic beam steering antennas, e.g. phased array antennas.

Description

Dihydronapthalene Derivatives The present invention relates to dihydronaphthalene derivatives, to liquid-crystalline media comprising same, and to high-frequency components comprising these media, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, tunable filters, tunable metamaterial structures, and electronic beam steering antennas (e.g., phased array antennas), and to devices comprising said components. The invention further relates to an optical component comprising said liquid-crystalline media, operable in the infrared region (IR) of the electromagnetic spectrum. The invention further relates to the use of said LC medium in the infrared region and to devices comprising said optical component. Liquid-crystalline media have been used for many years in electro-optical displays (liquid crystal displays: LCDs) in order to display information. More recently, however, liquid-crystalline media have also been proposed for use in components for microwave technology, such as, for example, in DE 102004029429 A and in JP 2005- 120208 (A). A. Gaebler, F. Goelden, S. Müller, A. Penirschke and R. Jakoby “Direct Simulation of Material Permittivities using an Eigen-Susceptibility Formulation of the Vector Variational Approach”, 12MTC 2009 – International Instrumentation and Measurement Technology Conference, Singapore, 2009 (IEEE), pp.463-467, describe the corresponding properties of the known liquid-crystal mixture E7 (Merck KGaA, Germany). DE 102004029429 A describes the use of liquid-crystal media in microwave technology, inter alia in phase shifters. Therein, liquid-crystalline media with respect to their properties in the corresponding frequency range have been discussed and liquid- crystalline media based on mixtures of mostly aromatic nitriles and isothiocyanates have been shown. However, compositions available for the use in microwave applications are still afflicted with several disadvantages. It is required to improve these media with respect to their general physical properties, the shelf life and the stability under operation in a device. In view of the multitude of different parameters which have to be considered and improved for the development of liquid crystalline media for microwave application it is desirable to have a broader range of possible mixture components for the development of such liquid-crystalline media. An object of the present invention is to provide a compound for the use in liquid crystalline media with improved properties relevant for the application in the microwave range of the electromagnetic spectrum. To solve the problem, a compound of formula D defined below is provided and a liquid crystalline medium comprising the compound. The present invention relates to a compound of formula D in which RD denotes H, straight-chain alkyl having 1 to 12 C atoms or branched alkyl having 2 to 12 C atom, or straight-chain alkenyl having 2 to 12 C atoms, or branched alkenyl having 3 to 12 C atoms, or straight-chain alkynyl having 2 to 12 C atoms or branched alkynyl having 4 to 12 C atoms, in which one or more CH2-groups may be replaced by , and where one or more non-adjacent CH2-groups may be replaced by O, or alternatively denotes a group RP, RP denotes halogen, CN, NCS, RF-, RF-O- or RF-S-, wherein RF denotes fluorinated alkyl having 1 to 9 C atoms, ZD1, ZD2, ZD3 and ZD4, identically or differently, denote -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -N=N-, -C=N-N=C-, -CH=N-, -N=CH-, -C ≡C-, -C ≡C-C ≡C-, or a single bond, where ZD1 alternatively denotes -O-, -S-, -CO-O-, -O-CO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -(CH2)3-, -(CH2)4-, -C2F4-, -CH2CF2-, -CF2CH2-, -CH=CH-CH2O-, -CH=CH-CO-O-, -OCH2-CH=CH-, or -O-CO-CH=CH-, XD denotes -C ≡C-CN, -NCS, or -C ≡C-NCS, , identically or differently, denote a radical selected from the following groups: a) the group consisting of 1,4-phenylene, 1,4-naphthylene, and 2,6-naphthylene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L, b) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, tetralin- 2,6-diyl, tetralin-5,8-diyl, decalin-2,6-diyl, bicyclo[1.1.1]pentane-1,3-diyl, 4,4´- bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl, and spiro[3.3]heptane-2,6-diyl, in which one or two CH groups may be replaced by N, one or more non-adjacent CH2 groups may be replaced by -O- and/or -S- and in which one or more H atoms may be replaced by L, c) the group consisting of thiophene-2,5-diyl, thieno[3,2-b]thiophene-2,5-diyl, and selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L, denotes , in which one or more H atoms are optionally replaced by L, L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy each having 1 to 12 C atoms, t1, t2, t3 and t4, identically or differently, are 0, 1 or 2, preferably 0 or 1, where t1 + t2 + t3 + t4 is 1, 2 or 3, preferably 1 or 2. According to another aspect of the present invention there is provided a liquid crystal medium comprising one or more compounds of formula D. Preferred embodiments of the present invention are subject-matter of the dependent claims or can also be taken from the description. Surprisingly, it has been found that it is possible to achieve liquid-crystalline media having excellent stability and at the same time a high dielectric anisotropy, suitably fast switching times, a suitable, nematic phase range, high tunability and low dielectric loss in the microwave range of the electromagnetic spectrum by using compounds of formula D in liquid-crystalline media. In particular, the media according to the invention comprising the compound according to the invention are distinguished by an improved figure-of-merit η due to a higher tunability τ and lower dielectric loss. The media according to the present invention are further distinguished by a high clearing temperature, a broad nematic phase range and excellent low-temperature stability (LTS). As a result, devices containing the media are operable under extreme temperature conditions. The media are further distinguished by high values of the dielectric anisotropy and low rotational viscosities. As a result, the threshold voltage, i.e. the minimum voltage at which a device is switchable, is very low. A low operating voltage and low threshold voltage is desired in order to enable a device having improved switching characteristics and high energy efficiency. Low rotational viscosities enable fast switching of the devices according to the invention. These properties as a whole make the media particularly suitable for use in components and devices for high-frequency technology and applications in the microwave range, in particular devices for shifting the phase of microwaves, tunable filters, tunable metamaterial structures, and electronic beam steering antennas (e.g. phased array antennas). According to another aspect of the present invention there is thus provided a component and a device comprising said component, both operable in the microwave region of the electromagnetic spectrum. Preferred components are phase shifters, varactors, wireless and radio wave antenna arrays, matching circuits and adaptive filters. The medium according to the invention is likewise suitable for use in the infrared region of the electromagnetic spectrum. The invention thus further relates to the use of the medium defined above in the infrared region of the electromagnetic spectrum, preferably in the A-band, and/or B- band and/or C-band, for phase modulation of said infrared light. According to another aspect of the present invention there is provided an optical component comprising the liquid crystal medium according to the invention sandwiched between a pair of substrates. The invention further relates to a device comprising the optical component according to the invention. Preferred devices are infrared imagers, wavelength selective switches, LCoS-SLM, LIDAR systems, wavelength-division multiplexing (WDM) systems, reconfigurable optical add-drop multiplexer (ROADM), and nonmechanical beam steering, e.g. steerable Electro Evanescent Optical Refraction (SEEOR) prism as published in the article P. McManamon, 2006, "Agile Nonmechanical Beam Steering," Opt. Photon. News 17(3): 24-29. According to another aspect of the present invention there is provided a method of spatially modulating infrared light, the method comprising, i) providing an optical component comprising first and second substrates facing each other and each having a surface, the first substrate comprising at least one first electrode, the second substrate comprising at least one second electrode, the component further comprising a liquid crystal layer sandwiched between the first and second substrates wherein the liquid crystal comprises one or more compounds selected from the compounds of formula D indicated above; ii) receiving incident infrared light at a surface of said optical component; iii) applying a predetermined voltage to each of the individual electrodes formed on the first and second substrate in order to modulate a refractive index of the liquid crystal layer. According to another aspect of the present invention there is provided a method of manufacturing an optical phase modulator, comprising at least the steps of a) providing a first substrate with a first electrode, optionally having a two dimensional array of individually electrically drivable cells; b) depositing a liquid crystal medium as set forth in claim 1 over the first substrate; and c) mounting a second substrate with a second electrode onto the liquid crystal material. The optical component according to the invention is distinguished by excellent operational stability when exposed to the environment because of high clearing temperature, broad nematic phase range and excellent low-temperature stability (LTS) of the liquid crystal medium used therein. As a result, the component and devices containing the component are operable under extreme temperature conditions. The media used in the component according to the invention are distinguished by high values of the dielectric anisotropy and low rotational viscosities. As a result, the threshold voltage, i.e. the minimum voltage at which a device is switchable, is very low. A low operating voltage and low threshold voltage is desired in order to enable a device having improved switching characteristics and high energy efficiency. Low rotational viscosities enable fast switching of the components and devices according to the invention. Herein, “high-frequency technology” means applications of electromagnetic radiation having frequencies in the range of from 1 MHz to 1 THz, preferably from 1 GHz to 500 GHz, more preferably 2 GHz to 300 GHz, particularly preferably from about 5 GHz to 150 GHz. As used herein, infrared region of the electromagnetic spectrum is taken to mean the spectral region of electromagnetic radiation having a wavelength in the range of from 0.75 µm to 1000 µm. As used herein, infrared A (IR-A) is taken to mean the spectral region of electromagnetic radiation having a wavelength in the range of from 0.75 µm to 1.4 µm. As used herein, infrared B (IR-B) is taken to mean the spectral region of electromagnetic radiation having a wavelength in the range of from 1.4 µm to 3 µm. As used herein, infrared C (IR-C) is taken to mean the spectral region of electromagnetic radiation having a wavelength in the range of from 3 µm to 1000 µm. Preferably, the optical component according to the invention operates at a wavelength in the range of from 750 nm to 2500 nm, in particular from 1530 nm to 1565 nm. A very preferred light source for applications according to the invention is an IR laser emitting light with a wavelength of 1,55 µm or an IR laser emitting light with a wavelength of 905 nm. As used herein, halogen is F, Cl, Br or I, preferably F or Cl, particularly preferably F. Herein, alkyl is straight-chain or branched or cyclic and has 1 to 15 C atoms, is preferably straight-chain and has, unless indicated otherwise, 1, 2, 3, 4, 5, 6 or 7 C atoms and is accordingly preferably methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl or n-heptyl. Herein, branched alkyl is preferably isopropyl, s-butyl, isobutyl, isopentyl, 2- methylbutyl, 2-methylhexyl or 2-ethylhexyl. As used herein, cyclic alkyl is taken to mean straight-chain or branched alkyl or alkenyl having up to 12 C atoms, preferably alkyl having 1 to 7 C atoms, in which a group CH2 is replaced with a carbocyclic ring having 3 to 5 C atoms, very preferably selected from the group consisting of cyclopropylalkyl, cyclobutylalkyl, cyclopentylalkyl and cyclopentenylalkyl. Herein, an alkoxy radical is straight-chain or branched and contains 1 to 15 C atoms. It is preferably straight-chain and has, unless indicated otherwise, 1, 2, 3, 4, 5, 6 or 7 C atoms and is accordingly preferably methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, n-hexoxy or n-heptoxy. Herein, an alkenyl radical is preferably an alkenyl radical having 2 to 15 C atoms, which is straight-chain or branched and contains at least one C-C double bond. It is preferably straight-chain and has 2 to 7 C atoms. Accordingly, it is preferably vinyl, prop-1- or -2-enyl, but-1-, -2- or -3-enyl, pent-1-, -2-, -3- or -4-enyl, hex-1-, -2-, -3-, -4- or -5-enyl, hept-1-, -2-, -3-, -4-, -5- or -6-enyl. If the two C atoms of the C-C double bond are substituted, the alkenyl radical can be in the form of E and/or Z isomer (trans/cis). In general, the respective E isomers are preferred. Of the alkenyl radicals, prop-2-enyl, but-2- and -3-enyl, and pent-3- and -4-enyl are particularly preferred. Herein, alkynyl is taken to mean an alkynyl radical having 2 to 15 C atoms, which is straight-chain or branched and contains at least one C-C triple bond.1- and 2-propynyl and 1-, 2- and 3-butynyl are preferred. In case RF denotes a halogenated alkyl-, alkoxy-, alkenyl or alkenyloxy it can be branched or unbranched. Preferably it is unbranched, mono- poly or perfluorinated, preferably perfluorinated and has 1, 2, 3, 4, 5, 6 or 7 C atoms, in case of alkenyl 2, 3, 4, 5, 6 or 7 C atoms. RP preferably denotes CN, NCS, Cl, F, -(CH2)n-CH=CF2, -(CH2)n-CH=CHF, -(CH2)n- CH=Cl2, -CnF2n+1, -(CF2)n-CF2H, -(CH2)n-CF3, -(CH2)n-CHF2, -(CH2)nCH2F, -CH=CF2, - O(CH2)n-CH=CF2, -O(CH2)nCHCl2, -OCnF2n+1, -O(CF2)n-CF2H, -O(CH2)nCF3, -O(CH2)n- CHF2, -O(CF)nCH2F, -OCF=CF2, -SCnF2n+1, -S(CF)n-CF3, wherein n is an integer from 0 to 7. The compounds of the general formula D are prepared by methods known per se, as described in the literature (for example in the standard works, such as Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Georg-Thieme- Verlag, Stuttgart), and under reaction conditions which are known and are suitable for said reactions. Use can be made here of variants which are known per se, but are not mentioned here in greater detail. If desired, the starting materials can also be formed in situ by not isolating them from the reaction mixture, but instead by immediately reacting them further into the compounds of the general formula D. Preferred synthetic pathways towards compounds according to the invention are exemplified in the reaction schemes below in which the occurring groups and parameters have the meanings given for formula D. It is further illustrated by means of the working examples and can be adapted to the particular desired compounds of the general formula D by choice of suitable starting materials. Fluorinated dihydronaphthalenes are described in JP2003-146919A and in JP2003- 183196A. Preferred starting materials are suitably substituted dihydronaphthalenes (1), that carry two different reactive groups X1 and X2. Because of the different reactivity of the groups X1 and X2 it is possible by choice of suitable reaction conditions to selectively react one of the groups X1 and X2 in a first reaction followed by derivatisation by means of the other group of X1 and X2. Suitable groups X1 and X2 are leaving groups selected from but not limited to Cl, Br, I, methane sulfonate (MsO), methylphenyl sulfonate (TsO), trifluoromethane sulfonate (TfO), perfluorononyl sulfonate (NsO), etc. This principle is described in the article E. Shirakawa et al., cobalt-catalysed cross-coupling of alkynyl Grignard reagents with alkenyl triflates, Chem. Commun., 2007, 4513–4515. Therein, a compound of formula 1 is shown in which X1 denotes TfO and X2 denotes Br (1a). The compound 1a can be made from 6-bromo-2-tetralone; 6-chloro and 6-iodo-2- tetralone are also known from the literature and can be reacted in a similar fashion. According to an aspect of the present invention, a process for the fabrication of a compound of formula D is provided in which a compound of the formula (1) is reacted in two steps by two different transition metal catalysed cross coupling reactions (Scheme 1). Preferred compounds of formula D in which the linking group ZD2 is a triple bond are for example obtained by Sonogashira coupling from the compound 1a. Scheme 1:
The compound 1 can also be reacted in other cross-coupling reactions, for example Suzuki reactions as described in WO2017133521 A1, to give the intermediate 5; in this embodiment ZD2 of formula D is a single bond (Scheme 2). Scheme 2 In analogy to known protocols, vinyl linking groups are introduced via Heck (Scheme 3, M = H) or Stille couplings (Scheme 3, M = Bu3Sn- ) as described in Scott, William J.; Pena, Michael R.; Sward, Katerina; Stoessel, Steven J.; Stille, J. K., Journal of Organic Chemistry 50(13), 2302-8, and Roth, Gregory P.; et al. Tetrahedron Letters (1995), 36(13), 2191-4. Scheme 3 Another suitable starting material for the synthesis of the compound according to the invention is 6-hydroxy-2-tetralone in which the hydroxyl group can be fist protected with a suitable phenol protecting group (PG), for example the methoxymethyl group (MOM), as described in the article Katherine M. Byrd, Caitlin N. Kent, and Brian S. J. Blagg, ChemMedChem 2017, 12, 2022 – 2029, which can then be further reacted via the triflate 8 in analogy to the bromo-derivative 1a (scheme 4). Scheme 4 The compounds 11 are transferred by the same processes described above into the intermediates 12, (scheme 5) in which G is a group that can be transferred into a group XD: Scheme 5 For example, a preferred precursor for the synthesis of the compounds of the formula D is the amino derivative of the formula N1 The compounds of formula N1 are reacted with a thiocarbonic acid derivative in which X and Y are leaving groups, or with CS2 to give the compounds of formula D. Preferred reagents for the process according to the invention for the transformation of compounds of the formula N1 into compounds of the formula D are carbon disulfide, thiophosgene, thiocarbonyl diimidazole, di-2-pyridyl thionocarbonate, bis(dimethylthiocarbamoyl) disulfide, dimethylthiocarbamoyl chloride and phenyl chlorothionoformate, very preferably thiophosgene. Another preferred pathway for the synthesis of isothiocyanates of the formula D includes the reaction of the N-hydroxycarboximidoyl chloride N2 with for example thiourea or a thiocarbonate. Compounds of formula D in which the terminal group XD denotes -C ≡C-CN can be synthesized in analogy to processes described in DE 19831093 A1. Compounds of formula D in which the terminal group XD denotes -C ≡C-NCS are prepared in accordance with a process described in M.S. Shvartsberg et al., Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya (1976), (10), 2292-5 (Scheme 6): the acetylenes 13 can be transferred into chlorides 14 by deprotonation and chlorination with N-chlorosuccinimide, which can be reacted with sodium amide to give the amines of formula N-3, from which said compounds of formula D (Scheme 6, D’) are obtainable using for example the known reagents listed above. In the reactions shown in the schemes 1 to 6 above and below, reactions towards compounds of the formula D are exemplified in which the group denotes . Obviously, the compounds of formula D in which denotes can be made in analogy to the described processes by choice of suitable reaction conditions or by for example first reacting the compound 1a with a building block that carries the terminal group precursor G (scheme 5) instead of the wing group RD. Scheme 6: The described reactions should only be regarded as illustrative. The person skilled in the art can carry out corresponding variations of the syntheses described and also follow other suitable synthetic routes in order to obtain compounds of the formula D. In a preferred embodiment of the present invention, the compound of formula D is selected from the compounds of the formulae D-1 and D-2: in which the occurring groups have the meanings given above for formula D, and t2 is 0, 1 or 2, t4 is 0 or 1, and t2+t4 is 1, 2 or 3, preferably 1 or 2. In formula D and its sub-formulae, in which RL, on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, or cycloalkyl having 3 to 5 C atoms, XD denotes -NCS, ZD1, ZD2, ZD3 and ZD4, identically or differently, denote -CH=CH-, -CF=CF-, -C ≡C-, or a single bond, where in which W denotes N, C-H, C-F or C-Cl, and Y1 and Y2, identically or differently, denote H, Cl, F, methyl or ethyl. In the formulae D-1 and D-2, preferably t2 and t4 are 0 or 1 where t2 + t4 is 1 or 2. Preferred compounds of the formula D-1 are selected from the following sub-formulae:
in which RD, XD , have the meanings defined above and preferably RD denotes straight chain alkyl or alkoxy having 1 to 12 C atoms, or straight chain alkenyl or alkynyl or alkenyloxy or alkynyloxy having 2 to 12 C atoms, or branched or cyclic alkyl or alkoxy or alkenyl or alkenyloxy having 3 to 12 C atoms, more preferably straight chain alkyl having 1 to 7 C atoms or alkynyl having 2 to 7 C atoms, XD denotes NCS, and
, in which Y, identically or differently, denotes F, Cl or CH3, preferably F. more preferably denotes L on each occurrence, identically or differently, denotes F, Cl, CH3 or C2H5, and n is 1 or 2, preferably 1. Very preferred are the compounds of the formulae D-1-1, D-1-2, D-1-3, D-1-4, D-1-9, D-1-10, D-1-11, D-1-12, D-2-1, D-2-2, D-2-3, D-2-4, D-2-9, D-2-10, D-2-11, and D-2-12. In a preferred embodiment the medium according to the invention comprises one or more compounds selected from the group of compounds of the formulae I, II and III: in which R1 denotes H, non-fluorinated alkyl or non-fluorinated alkoxy having 1 to 17, preferably 2 to 10 C atoms, or non-fluorinated alkenyl, non-fluorinated alkenyloxy or non-fluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, in which one or more CH2-groups may be replaced by preferably non-fluorinated alkyl or non-fluorinated alkenyl, n is 0, 1 or 2, on each occurrence, independently of one another, denote in which RL, on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, preferably H, methyl or ethyl, particularly preferably in which one or more H atoms may be replaced by alkyl having 1 to 6 C atoms or F, and wherein alternatively denotes
, and in case n = 2, one o preferably denotes and the other preferably denotes , or one of preferably denotes and the other preferably denotes , preferably , independently of one another, denote R2 denotes H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17, preferably 2 to 10 C atoms, or unfluorinated alkenyl, unfluori- nated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, in which one or more CH2-groups may be replaced by or , preferably unfluorinated alkyl or unfluorinated alkenyl, Z21 denotes trans-CH=CH-, trans-CF=CF- or -C≡C-, preferably -C≡C- or trans-CH=CH-, and independently of one another, denote in which RL, on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, preferably H, methyl or ethyl, particularly preferably H, in which one or more H atoms may be replaced by alkyl having 1 to 6 C atoms or F, preferably independently of one another, denote
more preferably R3 denotes H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17, preferably 2 to 10 C atoms, or unfluorinated alkenyl, unfluori- nated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, in which one or more CH2-groups may be replaced by preferably unfluorinated alkyl or unfluorinated alkenyl, one of Z31 and Z32 , preferably Z32; denotes trans-CH=CH-, trans-CF=CF- or -C≡C- and the other one, independently thereof, denotes -C≡C-, trans- CH=CH-, trans-CF=CF- or a single bond, preferably one of them, preferably Z32 denotes -C≡C- or trans-CH=CH- and the other denotes a single bond, and independently of one another, denote in which RL , on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, preferably H, methyl or ethyl, particularly preferably H, in which one or more H atoms may be replaced by alkyl having 1 to 6 C atoms or F, and wherein
independently of one another, denote
In the compounds of the formulae I, II and III, RL preferably denotes H. In another preferred embodiment, in the compounds of formulae I, II and III, one or two groups RL, preferably one group RL is different from H. In a preferred embodiment of the present invention, the compounds of formula I are selected from the group of compounds of the formulae I-1 to I-5: in which L1, L2 and L3 on each occurrence, identically or differently, denote H or F, and the other groups have the respective meanings indicated above for formula I and preferably R1 denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms. Preferably, the medium comprises one or more compounds selected from the compounds of the formula I-a and optionally one or more compounds selected from the compounds of the formula Cy-1 in which the occurring groups have the meanings given above for formula I-1. The total amount of compounds of the formula I-1 and/or Cy-I in the medium according to the invention is less than 10%, more preferably less than 5%, and in particular less than 2%. Particularly preferably, the medium contains no compound of formula Cy-1. The media preferably comprise one or more compounds of formula I-1, which are preferably selected from the group of the compounds of the formulae I-1a to I-1d, preferably of formula I-1b: in which R1 has the meaning indicated above for formula I and preferably denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms. The media preferably comprise one or more compounds of formula I-2, which are preferably selected from the group of the compounds of the formulae I-2a to I-2e, preferably of formula I-2c: in which R1 has the meaning indicated above for formula I and preferably denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms. The media preferably comprise one or more compounds of formula I-3, which are preferably selected from the group of the compounds of the formulae I-3a to I-3d , particularly preferably of formula I-3b: in which R1 has the meaning indicated above for formula I and preferably denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms. The media preferably comprise one or more compounds of formula I-4, which are preferably selected from the group of the compounds of the formulae I-4a to I-4e, particularly preferably of formula I-4b:
in which R1 has the meaning indicated above for formula I and preferably denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms. The media preferably comprise one or more compounds of formula I-5, which are preferably selected from the group of the compounds of the formulae I-5a to I-5d, particularly preferably of formula I-5b: in which R1 has the meaning indicated above for formula I and preferably denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms. The media preferably comprise one or more compounds of formula II, which are preferably selected from the group of the compounds of the formulae II-1 to II-3, preferably selected from the group of the compounds of the formulae II-1 and II-2: in which the occurring groups have the meanings given under formula II above and preferably R2 denotes unfluorinated alkyl or alkoxy having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms, and one of and the other, independently denotes and preferably R2 denotes CnH2n+1 or CH2=CH-(CH2)Z, and n denotes an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The compounds of formula II-1 are preferably selected from the group of the compounds of the formulae II-1a to II-1e:
in which R2 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH- (CH2)Z, and n denotes an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The compounds of formula II-2 are preferably selected from the group of the compounds of the formulae II-2a and II-2b: in which R2 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, n denotes an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The compounds of formula II-3 are preferably selected from the group of the compounds of the of formulae II-3a to II-3d: in which R2 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH- (CH2)Z, n denotes an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The compounds of formula III are preferably selected from the group of the compounds of the formulae III-1 to III-6, more preferably of the formulae selected from the group of the compounds of the formulae III-1, III-2, III-3 and III-4, and particularly preferably of formula III-1: in which Z31 and Z32 independently of one another denote trans-CH=CH- or trans-CF=CF-, preferably trans-CH=CH-, and in formula III-6 alternatively one of Z31 and Z32 may denote -C≡C- and the other groups have the meaning given above under formula III, and preferably R3 denotes unfluorinated alkyl or alkoxy having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms, and one of , very preferably and the others, independently of one another, denote
and preferably R3 denotes CnH2n+1 or CH2=CH-(CH2)Z, n denotes an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The compounds of formula III-1 are preferably selected from the group of the compounds of the formulae III-1a to III-1j, more preferably selected from the group of the compounds of the formulae III-1a, III-1b, III-1g and III-1h, particularly preferably of formula III-1b and/or III-1h: R3 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, n denotes an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The compounds of formula III-2 are preferably compounds of formula III-2a to III-2l, very preferably III-2b and/or III-2j:
in which R3 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, n denotes an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The compounds of formula III-5 are preferably selected from the compounds of formula III-5a: R3 has the meaning indicated above for formula III-5 and preferably denotes CnH2n+1, in which n denotes an integer in the range from 1 to 7, preferably in the range from 2 to 6. In a preferred embodiment of the present invention the medium comprises one or more compounds of the formula III selected from the group consisting of the formulae IIIa-1 to IIIa-4: in which R3 has the meanings defined for formula III and preferably denotes straight chain alkyl having 1 to 7 C atoms or branched alkyl having 1 to 9 C atoms, in which one or more CH2-groups may be replaced by , , , Very preferred are the compounds of the formulae IIIa-2 and IIIa-3. In a preferred embodiment, the media according to the invention comprise one or more compounds selected from the group of compounds of the formulae IIA-1-1 to IIA-1-12, very preferably IIA-1-1 or IIA-1-2:
in which R1 denotes alkyl or alkenyl having up to 7 C atoms, preferably ethyl, n-propyl, n- butyl or n-pentyl, n-hexyl, RL on each occurrence, the same or differently, denotes alkyl or alkenyl having 1 to 5 C atoms, or cycloalkyl or cycloalkenyl each having 3 to 6 C atoms, preferably methyl, ethyl, n-propyl, n-butyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclopent-1-enyl, very preferably ethyl, and from which the compounds of formula II-1 are excluded. Additionally, the liquid-crystalline media according to the present invention in a certain embodiment, which may be the same or different from the previous preferred embodiments preferably comprise one or more compounds of formula IV, s is 0 or 1, preferably 1, and preferably
particularly preferably L4 denotes H or alkyl having 1 to 6 C atoms, cycloalkyl having 3 to 6 C atoms or cycloalkenyl having 4 to 6 C atoms, preferably CH3, C2H5, n-C3H7, i-C3H7, cyclopropyl, cyclobutyl, cyclohexyl, cyclopent-1-enyl or cyclohex-1-enyl, and particularly preferably CH3, C2H5, cyclopropyl or cyclobutyl, X4 denotes H, alkyl having 1 to 3 C atoms or halogen, preferably H, F or Cl, more preferably H or F and very particularly preferably F, R41 to R44, independently of one another, denote unfluorinated alkyl or unfluorinated alkoxy, each having 1 to 15 C atoms, unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl, each having 2 to 15 C atoms, or cycloalkyl, alkylcycloalkyl, cycloalkenyl, alkylcycloalkenyl, alkylcycloalkyl- alkyl or alkylcycloalkenylalkyl, each having up to 15 C atoms, and alternatively one of R43 and R44 or both also denote H, preferably R41 and R42, independently of one another, denote unfluorinated alkyl or unfluorinated alkoxy, each having 1 to 7 C atoms, or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl, each having 2 to 6 C atoms, particularly preferably R41 denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl, each having 2 to 6 C atoms, and particularly preferably R42 denotes unfluorinated alkyl or unfluorinated alkoxy, each having 1 to 7 C atoms, and preferably R43 and R44 denote H, unfluorinated alkyl having 1 to 5 C atoms, unfluorinated cycloalkyl or cycloalkenyl having 3 to 7 C atoms, unfluorinated alkylcyclohexyl or unfluorinated cyclohexylalkyl, each having 4 to 12 C atoms, or unfluorinated alkylcyclohexylalkyl having 5 to 15 C atoms, particularly preferably cyclopropyl, cyclobutyl or cyclohexyl, and very particularly preferably at least one of R43 and R44 denotes n-alkyl, particularly preferably methyl, ethyl or n-propyl, and the other denotes H or n-alkyl, particularly preferably H, methyl, ethyl or n-propyl. Very preferably, the compounds of formula IV are selected from the compounds of the formula IV-1 in which R41 and R42, identically or differently, denote alkyl having 2, 3, 4, 5 or 6 C atoms. In a preferred embodiment of the present invention, the liquid-crystal medium additionally comprises one or more compounds selected from the group of compounds of the formulae V, VI, VII, VIII and IX: in which L51 denotes R51 or X51, L52 denotes R52 or X52, R51 and R52, independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17, preferably 2 to 10, C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, preferably alkyl or unfluorinated alkenyl, X51 and X52, independently of one another, denote H, F, Cl, -CN, SF5, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, fluorinated alkenyloxy or fluorinated alkoxyalkyl having 2 to 7 C atoms, preferably fluorinated alkoxy, fluorinated alkenyloxy, F or Cl, and independently of one another, denote , , L61 denotes R61 and, in the case where Z61 and/or Z62 denote trans-CH=CH- or trans-CF=CF-, alternatively also denotes X61, L62 denotes R62 and, in the case where Z61 and/or Z62 denote trans-CH=CH- or trans-CF=CF-, alternatively also denotes X62, R61 and R62, independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17, preferably 2 to 10, C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, preferably alkyl or unfluorinated alkenyl, X61 and X62, independently of one another, denote F or Cl, -CN, SF5, fluorinated alkyl or alkoxy having 1 to 7 C atoms or fluorinated alkenyl, alkenyloxy or alkoxyalkyl having 2 to 7 C atoms, one of Z61 and Z62 denotes trans-CH=CH-, trans-CF=CF- or -C≡C- and the other, independently thereof, denotes trans-CH=CH-, trans-CF=CF- or a single bond, preferably one of them denotes -C≡C- or trans-CH=CH- and the other denotes a single bond, and independently of one another, denote and x denotes 0 or 1; L71 denotes R71 or X71, L72 denotes R72 or X72, R71 and R72, independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17, preferably 2 to 10, C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, preferably alkyl or unfluorinated alkenyl, X71 and X72, independently of one another, denote H, F, Cl, -CN, -NCS, -SF5, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, unfluorinated or fluorinated alkenyloxy or unfluorinated or fluorinated alkoxyalkyl having 2 to 7 C atoms, preferably fluorinated alkoxy, fluorinated alkenyloxy, F or Cl, and Z71 to Z73, independently of one another, denote trans-CH=CH-, trans-CF=CF-, - C≡C- or a single bond, preferably one or more of them denote a single bond, particularly preferably all denote a single bond and independently of one another, denote preferably
R81 and R82, independently of one another, denote H, unfluorinated alkyl or alkoxy having 1 to 15, preferably 2 to 10, C atoms or unfluorinated alkenyl, alkenyloxy or alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, preferably unfluorinated alkyl or alkenyl, one of Z81 and Z82 denotes trans-CH=CH-, trans-CF=CF- or -C≡C- and the other, independently thereof, denotes trans-CH=CH-, trans-CF=CF- or a single bond, preferably one of them denotes -C≡C- or trans-CH=CH- and the other denotes a single bond, and L91 denotes R91 or X91, L92 denotes R92 or X92, R91 and R92, independently of one another, denote H, unfluorinated alkyl or alkoxy having 1 to 15, preferably 2 to 10, C atoms or unfluorinated alkenyl, alkenyloxy or alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, preferably unfluorinated alkyl or alkenyl, X91 and X92, independently of one another, denote H, F, Cl, -CN, -NCS, -SF5, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, unfluorinated or fluorinated alkenyloxy or unfluorinated or fluorinated alkoxyalkyl having 2 to 7 C atoms, preferably fluorinated alkoxy, fluorinated alkenyloxy, F or Cl, and Z91 to Z93, independently of one another, denote trans-CH=CH-, trans-CF=CF-, - C≡C- or a single bond, preferably one or more of them denotes a single bond, and particularly preferably all denote a single bond, independently of one another, denote In a preferred embodiment of the present invention, the liquid-crystal medium comprises one or more compounds of the formula V, preferably selected from the group of the compounds of the formulae V-1 to V-3, preferably of the formulae V-1 and/or V-2 and/or V-3, preferably of the formulae V-1 and V-2: in which the occurring groups have the respective meanings indicated above for formula V and preferably R51 denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms, R52 denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms or unfluorinated alkoxy having 1 to 7 C atoms, X51 and X52, independently of one another, denote F, Cl, -OCF3, -CF3, -CN or -SF5, preferably F, Cl, -OCF3 or -CN. The compounds of the formula V-1 are preferably selected from the group of the compounds of the formulae V-1a to V-1d, preferably V-1c and V-1d :
in which the parameters have the respective meanings indicated above for formula V-1 and in which Y51 and Y52, in each case independently of one another, denote H or F, and preferably R51 denotes alkyl or alkenyl, and X51 denotes F, Cl or -OCF3. The compounds of the formula V-2 are preferably selected from the group of the compounds of the formulae V-2a to V-2e and/or from the group of the compounds of the formulae V-2f and V-2g:
where in each case the compounds of the formula V-2a are excluded from the compounds of the formulae V-2b and V-2c, the compounds of the formula V-2b are excluded from the compounds of the formula V-2c and the compounds of the formula V-2f are excluded from the compounds of the formula V-2g, and in which the parameters have the respective meanings indicated above for formula V-1 and in which Y51 and Y52, in each case independently of one another, denote H or F, and preferably Y51 and Y52 denotes H and the other denotes H or F, preferably likewise denotes H. The compounds of the formula V-3 are preferably compounds of the formula V-3a: in which the parameters have the respective meanings indicated above for formula V-1 and in which preferably X51 denotes F, Cl, preferably F, X52 denotes F, Cl or -OCF3, preferably -OCF3. The compounds of the formula V-1a are preferably selected from the group of the compounds of the formulae V-1a-1 and V-1a-2: in which R51 has the meaning indicated above and preferably denotes CnH2n+1, in which n denotes an integer in the range from 1 to 7, preferably in the range from 1 to 6 and particularly preferably 3 to 5. The compounds of the formula V-1b are preferably compounds of the formula V-1b-1: in which R51 has the meaning indicated above and preferably denotes CnH2n+1, in which n denotes an integer in the range from 1 to 7, preferably in the range from 1 to 6 and particularly preferably 3 to 5. The compounds of the formula V-1c are preferably selected from the group of the compounds of the formulae V-1c-1 to V-1c-4, particularly preferably selected from the group of the compounds of the formulae V-1c-1 and V-1c-2: in which R51 has the meaning indicated above and preferably denotes CnH2n+1, in which n denotes an integer in the range from 1 to 7, preferably in the range from 1 to 6 and particularly preferably 3 to 5. The compounds of the formula V-1d are preferably selected from the group of the compounds of the formulae V-1d-1 and V-1d-2, particularly preferably the compound of the formula V-1d-2: 1 2 in which R51 has the meaning indicated above and preferably denotes CnH2n+1, in which n denotes an integer in the range from 1 to 7, preferably in the range from 1 to 6 and particularly preferably 3 to 5. The compounds of the formula V-2a are preferably selected from the group of the compounds of the formulae V-2a-1 and V-2a-2, particularly preferably the compounds of the formula V-2a-1: in which R51 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R52 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 1 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. Preferred combinations of R51 with R52, in particular in the case of formula V-2a-1, are (CnH2n+1 and CmH2m+1), (CnH2n+1 and O-CmH2m+1), (CH2=CH-(CH2)Z and CmH2m+1), (CH2=CH-(CH2)Z and O-CmH2m+1) and (CnH2n+1 and (CH2)Z-CH=CH2). Preferred compounds of the formula V-2b are the compounds of the formula V-2b-1: in which R51 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R52 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 1 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combination of R51 with R52 here is, in particular, CnH2n+1 and CmH2m+1. Preferred compounds of the formula V-2c are the compounds of the formula V-2c-1: in which R51 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R52 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 1 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combination of (R51 and R52) here is, in particular, (CnH2n+1 and CmH2m+1). Preferred compounds of the formula V-2d are the compounds of the formula V-2d-1: in which R51 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R52 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 1 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combination of (R51 and R52) here is, in particular, (CnH2n+1 and CmH2m+1). Preferred compounds of the formula V-2e are the compounds of the formula V-2e-1: in which R51 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R52 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combination of (R51 and R52) here is, in particular, (CnH2n+1 and O-CmH2m+1). Preferred compounds of the formula V-2f are the compounds of the formula V-2f-1: in which R51 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R52 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combinations of (R51 and R52) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O-CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1). Preferred compounds of the formula V-2g are the compounds of the formula V-2g-1: in which R51 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R52 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combinations of (R51 and R52) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O-CmH2m+1), particularly preferably (CnH2n+1 and O-CmH2m+1). The compounds of the formula VI are preferably selected from the group of the compounds of the formulae VI-1 to VI-5: in which Z61 and Z62 denote -C ≡C-, trans-CH=CH- or trans-CF=CF-, preferably -C ≡C- or trans-CH=CH-, and the other occurring groups and parameters have the meaning given above under formula VI, and preferably R61 and R62, independently of one another, denote H, unfluorinated alkyl or alkoxy having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms, X62 denotes F, Cl, -OCF3 or -CN, The compounds of the formula VI-1 are preferably selected from the group of the compounds of the formulae VI-1a and VI-1b, more preferably selected from compounds of the formula VI-1a:
in which R61 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R62 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combinations of (R61 and R62) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O-CmH2m+1), in the case of formula VI-1a particularly preferably (CnH2n+1 and CmH2m+1) and in the case of formula VI-1b particularly preferably (CnH2n+1 and O-CmH2m+1). The compounds of the formula VI-3 are preferably selected from the compounds of the formula VI-3a to VI-3e:
in which the parameters have the meaning given above under formula VI-3 and preferably R61 has the meaning indicated above and preferably denotes CnH2n+1, in which n denotes an integer in the range from 1 to 7, preferably in the range from 1 to 5, and X62 denotes -F, -Cl, -OCF3, or -CN. The compounds of the formula VI-4 are preferably selected from compounds of the for- mulae VI-4a to VI-4e:
in which the parameters have the meaning given above under formula VI-4 and preferably R61 has the meaning indicated above and preferably denotes CnH2n+1, in which n denotes an integer in the range from 1 to 7, preferably in the range from 1 to 5, and X62 denotes F, Cl, OCF3, or -CN. The compounds of the formula VI-5 are preferably selected from the compounds of the formulae VI-5a to VI-5d, preferably VI-5b:
in which the parameters have the meaning given above under formula VI-5 and preferably R61 has the meaning indicated above and preferably denotes CnH2n+1, in which n denotes an integer in the range from 1 to 7, preferably in the range from 1 to 5, and X62 denotes -F, -Cl, -OCF3, or -CN, particularly preferably -OCF3. The compounds of the formula VII are preferably selected from the group of the compounds of the formulae VII-1 to VII-6:
where the compounds of the formula VII-5 are excluded from the compounds of the formula VII-6, and in which the parameters have the respective meanings indicated above for formula VII, Y71, Y72, Y73 independently from one another, denote H or F, and preferably R71 denotes unfluorinated alkyl or alkoxy, each having 1 to 7 C atoms, or unfluorinated alkenyl having 2 to 7 C atoms, R72 denotes unfluorinated alkyl or alkoxy, each having 1 to 7 C atoms, or unfluorinated alkenyl having 2 to 7 C atoms, X72 denotes F, Cl; NCS or -OCF3, preferably F or NCS, and particularly preferably R71 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R72 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The compounds of the formula VII-1 are preferably selected from the group of the compounds of the formulae VII-1a to VII-1d: in which X72 has the meaning given above for formula VII-2 and R71 has the meaning indicated above and preferably denotes CnH2n+1, in which n denotes an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2, and X72 preferably denotes F. The compounds of the formula VII-2 are preferably selected from the group of the compounds of the formulae VII-2a and VII-2b, particularly preferably of the formula VII- 2a: in which R71 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R72 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combinations of (R71 and R72) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O-CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1). The compounds of the formula VII-3 are preferably compounds of the formula VII-3a: in which R71 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R72 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combinations of (R71 and R72) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O-CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1). The compounds of the formula VII-4 are preferably compounds of the formula VII-4a: in which R71 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R72 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combinations of (R71 and R72) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O-CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1). The compounds of the formula VII-5 are preferably selected from the group of the compounds of the formulae VII-5a and VII-5b, more preferably of the formula VII-5a: in which R71 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R72 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combinations of (R71 and R72) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O-CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1). The compounds of the formula VII-6 are preferably selected from the group of the compounds of the formulae VII-6a and VII-6b: in which R71 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R72 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combinations of (R71 and R72) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O-CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1). The compounds of the formula VII-7 are preferably selected from the group of the compounds of the formulae VII-7a to VII-7d: in which R71 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, X72 denotes F, -OCF3 or -NCS, n denotes an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The compounds of the formula VIII are preferably selected from the group of the compounds of the formulae VIII-1 to VIII-3, more preferably these compounds of the formula VIII predominantly consist, even more preferably essentially consist and very particularly preferably completely consist thereof: in which one of Y81 and Y82 denotes H and the other denotes H or F, and R81 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R82 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combinations of (R81 and R82) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O-CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1). The compounds of the formula VIII-1 are preferably selected from the group of the compounds of the formulae VIII-1a to VIII-1c: in which R81 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R82 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combinations of (R81 and R82) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O-CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1). The compounds of the formula VIII-2 are preferably compounds of the formula VIII-2a: in which R81 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R82 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combinations of (R81 and R82) here are, in particular, (CnH2n+1 and CmH2m+1), (CnH2n+1 and O-CmH2m+1) and (CH2=CH-(CH2)Z and CmH2m+1), particularly preferably (CnH2n+1 and CmH2m+1). The compounds of the formula VIII-3 are preferably compounds of the formula VIII-3a: in which R81 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R82 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combinations of (R81 and R82) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O-CmH2m+1). The compounds of the formula IX are preferably selected from the group of the compounds of the formulae IX-1 to IX-3:
in which the parameters have the respective meaning indicated above under formula IX and preferably one of and in which R91 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R92 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combinations of (R91 and R92) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O-CmH2m+1). The compounds of the formula IX-1 are preferably selected from the group of the compounds of the formulae IX-1a to IX-1e: in which the parameters have the meaning given above and preferably R91 has the meaning indicated above and preferably denotes CnH2n+1, and n denotes an integer in the range from 0 to 15, preferably in the range from 1 to 7 and particularly preferably 1 to 5, and X92 preferably denotes F or Cl. The compounds of the formula IX-2 are preferably selected from the group of the compounds of the formulae IX-2a and IX-2b:
in which R91 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R92 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combination of (R91 and R92) here is, in particular, (CnH2n+1 and CmH2m+1). The compounds of the formula IX-3 are preferably compounds of the formulae IX-3a and IX-3b: in which R91 has the meaning indicated above and preferably denotes CnH2n+1 or CH2=CH-(CH2)Z, and R92 has the meaning indicated above and preferably denotes CmH2m+1 or O-CmH2m+1 or (CH2)Z-CH=CH2, and in which n and m, independently of one another, denote an integer in the range from 1 to 7, preferably in the range from 2 to 6 and particularly preferably 3 to 5, and z denotes 0, 1, 2, 3 or 4, preferably 0 or 2. The preferred combinations of (R91 and R92) here are, in particular, (CnH2n+1 and CmH2m+1) and (CnH2n+1 and O-CmH2m+1), particularly preferably (CnH2n+1 and O-CmH2m+1). In a preferred embodiment of the present invention the medium comprises one or more compounds of formula X in which R101 denotes H, alkyl or alkoxy having 1 to 15, preferably 2 to 10, C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, preferably alkyl or alkenyl, X101 denotes H, F, Cl, -CN, SF5, NCS, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, fluorinated alkenyloxy or fluorinated alkoxyalkyl having 2 to 7 C atoms, preferably fluorinated alkoxy, fluorinated alkenyloxy, F, Cl or NCS, particularly preferably NCS, Y101 denotes methyl, ethyl or Cl, Y102 denotes H, methyl, ethyl, F or Cl, preferably H or F, Z101, Z102 identically or differently, denote a single bond, -CH=CH-, -CF=CF- or -C ≡C-, independently of one another, denote and where , and n is 0 or 1. Preferably, the compounds of formula X are selected from the sub-formulae X-1 and X-2 in which the occurring groups and parameters have the meanings given above for formula X. Particularly preferably, the media according to the invention comprise one or more compounds selected from the group of compounds of the formulae X-1-1 to X-1-9 In which R101 denotes alkyl having 1 to 7 C atoms. In a preferred embodiment, the medium according to the invention comprises one or more compounds of formula XI I in which RS denotes H, alkyl or alkoxy having 1 to 12 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 12 C atoms, in which one or more CH2-groups may be replaced by , , , and in which one or more H atoms may be replaced by F, d , on each occurrence, independently of one another, denote , in which RL, on each occurrence identically or differently, denotes H, Cl or straight-chain, branched or cyclic alkyl having 1 to 6 C atoms, LS1, LS2 identically or differently, denote H, Cl or F, RS1, RS2, identically or differently, denote H, alkyl or alkenyl, having up to 6 C atoms, or cyclopropyl, cyclobutyl, cyclopentenyl, or cyclopentyl, RTh1, RTh2 identically or differently, denote H, alkyl or alkenyl or alkoxy, having up to 6 C atoms, or cyclopropyl, cyclobutyl, cyclopentenyl or cyclopentyl, ZS1, ZS2, ZS3 identically or differently, denote -CH=CH-, -CH=CF-, -CF=CH-, -CF=CF-, -C ≡C-, or a single bond, a, b identically or differently, are 0 or 1. Preferably, the compounds of formula XI are selected from the group of compounds of the formulae XI-1 to XI-24: in which the occurring groups have the meanings given above for formula XI and preferably RS denotes alkyl or alkenyl having 2 to 6 C atoms, in which one or more CH2-groups may be replaced by RS1 and RS2 identically or differently, denote H or alkyl having 1 to 6 C atoms, preferably H, RS3 denotes H, F or alkyl, having up to 6 C atoms, or cyclopropyl, preferably H, F or ethyl, very preferably H, LS1 and LS2 identically or differently, denote H or F, preferably F. Preferably, the medium comprises one or more compounds of formula XII in which R12 denotes H, alkyl or alkoxy having 1 to 12 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 12 C atoms, in which one or more CH2-groups may be replaced by , or denote P s a group R , RP denotes halogen, CN, NCS, RF, RF-O- or RF-S-, wherein RF denotes fluorinated alkyl or fluorinated alkenyl having up to 9 C atoms, Z121, Z122 identically or differently, denote -CH=CH-, -CF=CF-, -CH=CF- , -CF=CH-, -C ≡C- or a single bond, preferably -C ≡C- or a single bond, X1, X2, X3 and X4 identically or differently, denote Cl or F, preferably F, t is 0 or 1, and denote a radical selected from the following groups: a) the group consisting of 1,4-phenylene, 1,4-naphthylene, and 2,6- naphthylene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L, wherein tetrafluoro-1,4-phenylene is excluded, b) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, bicyclo[1.1.1]pentane-1,3-diyl, 4,4´-bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, in which one or more non-adjacent CH2 groups may be replaced by -O- and/or -S- and in which one or more H atoms may be replaced by F, c) the group consisting of thiophene-2,5-diyl, thieno[3,2-b]thiophene-2,5- diyl, selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L, L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkyl- carbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, and where the compounds of the formula XII are excluded from the compounds of the formulae I II and III. The compounds of formula XII are preferably selected from the compounds of the sub- formulae XII-1 to XII-11:
in which L1, L2 and L3 identically or differently, denote H, F, Cl, methyl, ethyl, n-propyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclopentenyl, and R12, X1, X2, X3 and X4 have the meanings given above for formula XII. Very preferably, the medium comprises a compound of formula XII-3, in which the occurring groups have the meanings given above and particularly preferably L1 denotes H, X1, X2, X3 and X4 denote F and R12 denotes alkyl having 1 to 7 C atoms. The medium according to the invention preferably comprises one or more compounds of the formula XIII in which R13 denotes H, alkyl or alkoxy having 1 to 12 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 12 C atoms, in which one or more CH2-groups may be replaced by , or a group RP, RP denotes halogen, CN, NCS, RF, RF-O- or RF-S-, wherein RF denotes fluorinated alkyl or fluorinated alkenyl having up to 9 C atoms, Z131, Z132, Z133 identically or differently, denote -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C ≡C- or a single bond, preferably -C ≡C- or a single bond, X1, X2 identically or differently, denote H, Cl, F, CH3 or C2H5, preferably H or F, Y1, Y2, Y3, Y4, identically or differently, denote H, F, Cl, or straight chain or branched or cyclic alkyl, alkenyl, alkoxy or alkenyloxy, each having up to 12 C atoms, where at least one of Y1, Y2, Y3 and Y4 is different from F, s is 0, 1 or 2, preferably 0 or 1, t is 0, 1 or 2, preferably 0 or 1, and s + t is 0, 1 or 2, preferably 0 or 1, denote a radical selected from the following groups: a) the group consisting of 1,4-phenylene, 1,4-naphthylene, and 2,6- naphthylene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L, b) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, bicyclo[1.1.1]pentane-1,3-diyl, 4,4´-bicyclohexylene, bicyclo[2.2.2]octane- 1,4-diyl, spiro[3.3]heptane-2,6-diyl, in which one or more non-adjacent CH2 groups may be replaced by -O- and/or -S- and in which one or more H atoms may be replaced by F, c) the group consisting of thiophene-2,5-diyl, thieno[3,2-b]thiophene-2,5-diyl, selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L, L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms. In a preferred embodiment of the present invention, the compounds of formula XIII are selected from the compounds of the formulae XIII-1 to XIII-20, very preferably from the compounds of the formulae XIII-1 to XIII-13:
in which the occurring groups have the meanings indicated above for formula XIII and its sub-formulae and preferably R13 denotes alkyl having 1 to 7 C atoms, Y1, Y2, Y3, and Y4, identically or differently, denote H, F, Cl, methyl, ethyl, n-propyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclopentenyl, and more preferably Y1 and Y2 independently denote H or F, in particular H, and Y3 and Y4 very preferably denote H, and L1 and L2, identically or differently, very preferably denote H, F, methyl or ethyl, in particular H. Preferably, the medium according to the invention comprises one or more compounds of formula T in which RT denotes halogen, CN, NCS, RF, RF-O- or RF-S-, wherein RF denotes fluorinated alkyl or fluorinated alkenyl having up to 12 C atoms, on each occurrence, independently of one another, denote L4 and L5 identically or differently, denote F, Cl or straight-chain or branched or cyclic alkyl or alkenyl each having up to 12 C atoms; ZT3, ZT4 identically or differently, denote -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C ≡C- or a single bond, and t is 0 or 1. In a preferred embodiment, the liquid crystalline media according to the invention comprise one or more compounds selected from the group of compounds of the formulae T-1a to T-3b below:
in which have the meanings given above and n is 1, 2, 3, 4, 5 ,6 or 7, preferably 1, 2, 3 or 4, particularly preferably 1. In a particularly preferred embodiment of the present invention the media comprise one or more compounds selected from the compounds of the formulae T-1a and T-2a. Preferred compounds of formula T-1a are selected from the group of compounds of the following sub-formulae:
in which n is 1, 2, 3 or 4, preferably 1. Preferred compounds of formula T-2a are selected from the group of compounds of the following sub-formulae:
in which n is 1, 2, 3 or 4, preferably 1. Preferred compounds of formula T-3a are selected from the group of compounds of the following sub-formulae:
in which n is 1, 2, 3 or 4, preferably 1. Very preferably, the medium according to the invention comprises one or more compounds of formula T-1a-5. In an embodiment, the medium according to the invention comprises one or more compounds of formula I, II, III, IV, V, VI, VII, VIII, IX, X in which the radical R1, R2, R3, R41, R42, R51, R52, R61, R62, R71, R72, R81, R82, R91, R92, R101, R102 and RS, respectively, is a cyclic alkyl group. Very preferred compounds comprising a cyclic alkyl group are selected from the compounds of the formulae Cy-1 to Cy-14
In a preferred embodiment, the medium according to the invention comprises a compound of formula N in which RN denotes H, alkyl or alkoxy having 1 to 12 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 12 C atoms, in which one or more CH2-groups may be replaced by r or denotes a group RP, RP denotes halogen, CN, NCS, RF, RF-O- or RF-S-, wherein RF denotes fluorinated alkyl having 1 to 9 C atoms or fluorinated alkenyl having 2 to 9 C atoms, ZN1 and ZN2 ,identically or differently, denote -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C ≡C- or a single bond, preferably -C ≡C- or a single bond, W denotes N, C-F or C-Cl, X1 and X2, identically or differently, denote H, Cl, F, methyl or ethyl, denote a radical selected from the following groups: a) the group consisting of 1,4-phenylene, 1,4-naphthylene, and 2,6-naphthylene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L, b) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, bicyclo- [1.1.1]pentane-1,3-diyl, 4,4´-bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl or spiro[3.3]heptane-2,6-diyl, in which one or more non-adjacent CH2 groups may be replaced by -O- and/or -S- and in which one or more H atoms may be replaced by F, c) the group consisting of thiophene-2,5-diyl, thieno[3,2-b]thiophene-2,5-diyl or selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by RL, L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, and n is 0, 1 or 2. The compound of formula N is preferably selected from the group consisting of the formulae N-1, N-2 and N-3: in which RN , ZN1 , ZN2, X1, X2 and n, have the respective meanings given above for formula N. In formula N and its sub-formulae N-1, N-2 and N-3, preferably d in which RL, on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, preferably H, methyl or ethyl, particularly preferably H, L denotes F or alkyl having 1 to 6 C atoms, and r is 0, 1, 2, 3, 4, 5 or 6, preferably 0 or 1,
In a preferred embodiment, in formula N and its sub-formulae the radicals X1 and X2 both denote H. In a preferred embodiment, in formula N and its sub-formulae the radical X1 denotes H and the radical X2 denotes F or Cl. In a preferred embodiment, in formula N and its sub-formulae the radical X1 denotes F or Cl and the radical X2 denotes H. In a preferred embodiment, in formula N and its sub-formulae the radicals X1 and X2 denote F or Cl, preferably both F. The compounds of the formulae N-1, N-2 and N-3 are preferably selected from the group consisting of the formulae N-1-1 to N-1-10, N-2-1 to N-2-10 and N-3-1 to N-3-10:
in which RN, X1 and X2 have the meanings given above and L, on each occurrence identically or differently denotes H, F, methyl, ethyl or cyclopropyl. In a preferred embodiment, the medium according to the invention comprises a compound of formula NI I in which RN, , ZN1 , ZN2, W, X1, X2 and n, have the respective meanings given in claim 1 for formula N. The compounds of formula NI are preferably selected from the compounds of the formulae NI-1 and NI-2 in which RN, ZN1, ZN2, have the meanings given above for formula N, Y1 and Y2, identically or differently, denote H, F or Cl, and t is 0 or 1. In the compounds of formula NI or NI-1 or NI-2 independently of one another, preferably denot wherein L1 and L2 , identically or differently, denote F, Cl or straight chain or branched or cyclic alkyl or alkenyl each having up to 12 C atoms. In the compounds of formula NI or NI-1 or NI-2, ZN1 and ZN2, identically or differently, preferably denote -C ≡C- or a single bond. In a preferred embodiment of the present invention, the compounds of formula NI-1 and NI-2 are selected from the compounds of the formulae NI-1-1 to NI-1-12 and NI-2- 1 to NI-2-12
in which L1, L2 and L3 identically or differently, denote H, F, Cl, methyl, ethyl, n-propyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclopentenyl, and RN, Y1 and Y2 have the meanings given above for formula N-1 and N-2, and in which very preferably the group denotes In a preferred embodiment, in the compounds of formula NI and its sub-formulae, one or both of Y1 and Y2 denote H, preferably both. In another preferred embodiment, in the compounds of formula N and its sub-formulae both of Y1 and Y2 denote F. Preferably, the medium according to the invention comprises one or more compounds of formula UI in which RU denotes H, straight-chain or branched non-fluorinated alkyl having 1 to 12 C atoms or non-fluorinated alkenyl having 2 to 12 C atoms, in which one or more CH2-groups may be replaced , , where one or more non-adjacent CH2-groups may be replaced by O, or denotes a group RP, RP denotes halogen, CN, NCS, fluorinated alkyl, RF-O- or RF-S-, wherein RF denotes fluorinated alkyl or fluorinated alkenyl having up to 9 C atoms, ZU1 denotes -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C ≡C- or -C ≡C-C ≡C-, preferably -CF=CF- or -C ≡C-, XU1, XU2, identically or differently, denote Cl or F, preferably F. denote a radical selected from the following groups: a) the group consisting of 1,4-phenylene, 1,4-naphthylene, and 2,6-naphthylene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L, b) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, tetralin- 2,6-diyl, tetralin-5,8-diyl, decalin-2,6-diyl, bicyclo[1.1.1]pentane-1,3-diyl, 4,4´- bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl, and spiro[3.3]heptane-2,6-diyl, in which one or two CH groups may be replaced by N, one or more non-adjacent CH2 groups may be replaced by -O- and/or -S- and in which one or more H atoms may be replaced by L, c) the group consisting of thiophene-2,5-diyl, thieno[3,2-b]thiophene-2,5-diyl, selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L, L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy each having 1 to 12 C atoms, u is 0 or 1, v is 0 or 1, with the proviso tha and do not both denote optionally fluorinated 1,4-phenylene and where the compounds of the formula UI and its sub- formulae are excluded from the compounds of the formulae I, II and III. The compounds of formula UI are preferably selected from the group of compounds consisting of the formulae UI-1, UI-2 and UI-3: in which RU U1 U2 , X and X have the meanings given above for formula UI, and where in formula UI-3 at least one of and denotes trans-1,4-cyclohexylene, 1,4-cyclohexenylene, tetralin-2,6-diyl, tetralin-5,8-diyl, decalin-2,6-diyl, bicyclo[1.1.1]pentane-1,3-diyl, 4,4´-bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl, or spiro[3.3]heptane-2,6-diyl, in which one or two CH groups may be replaced by N, one or more non-adjacent CH2 groups may be replaced by -O- and/or -S- and in which one or more H atoms may be replaced by L, wherein L, on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkyl carbonyloxy or alkoxycarbonyloxy each having 1 to 12 C atoms, and preferably XU1 and XU2 denote F, RU preferably denotes straight chain or branched or cyclic alkyl or alkenyl having 1 to 7 C atoms, or fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms, and identically or differently, preferably denote in which L R , on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, or denot e or in which one or more H atoms may be replaced by alkyl having 1 to 6 C atoms or F. very preferably denote in which RL denotes H or alkyl having 1 to 6 C atoms. Preferred compounds of formula UI are selected from the following sub-formulae:
in which RU has the meanings given above and preferably denotes straight chain or branched alkyl having 1 to 7 C atoms, in particular methyl, ethyl, n-propyl, n-butyl, n- pentyl, n-hexyl or n-heptyl. The liquid crystal medium according to the invention preferably comprises one or more compounds of the formula UII in which RU denotes H, straight-chain or branched alkyl having 1 to 12 C atoms or alkenyl having 2 to 12 C atoms, in which one or more CH2-groups may be replaced by , where one or more non-adjacent CH2-groups may be replaced by O, or a group RP, RP denotes halogen, CN, NCS, RF-, RF-O- or RF-S-, wherein RF denotes fluorinated alkyl or fluorinated alkenyl having up to 9 C atoms, ZU1, ZU2 identically or differently, denote -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C ≡C-, -C ≡C-C ≡C- or a single bond, preferably -CF=CF-, -C ≡C- or a single bond, very preferably -C ≡C- or a single bond, XU1, XU2, identically or differently, denote Cl or F, preferably F, denote a radical selected from the following groups: a) the group consisting of 1,4-phenylene, 1,4-naphthylene, and 2,6-naphthylene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L, b) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, tetralin- 2,6-diyl, tetralin-5,8-diyl, decalin-2,6-diyl, bicyclo[1.1.1]pentane-1,3-diyl, 4,4´- bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl, and spiro[3.3]heptane-2,6-diyl, in which one or two CH groups may be replaced by N, one or more non-adjacent CH2 groups may be replaced by -O- and/or -S- and in which one or more H atoms may be replaced by L, c) the group consisting of thiophene-2,5-diyl, thieno[3,2-b]thiophene-2,5-diyl, selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L, L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy each having 1 to 12 C atoms, and u is 0, 1 or 2, preferably 1, where the compounds of formula UI are excluded from the compounds of formula UII, and where the compounds of the formula UII and its sub-formulae are excluded from the compounds of the formulae I, II, and III. The medium preferably comprises one or more compounds of the formula UI and one or more compounds of the formula UII. Preferably, the compounds of the formula UII are selected from the compounds of the formulae UII-1, UII-2 and UII-3, preferably UII-1 and UII-2, in particular UII-1: in which the occurring groups have the meanings given above for formula UII and preferably , identically or differently, denote
XU1 and XU2 denote F, and RU preferably denotes straight chain or branched or cyclic alkyl or alkenyl having 1 to 7 C atoms, or fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms. Very preferred compounds of formula UII are selected from the following sub-formulae: in which RU has the meanings given above and preferably denotes straight chain or branched alkyl having 1 to 7 C atoms, in particular methyl, ethyl, n-propyl, n-butyl, n- pentyl, n-hexyl or n-heptyl. The medium according to the invention preferably comprises one or more compounds of the formulae GF-1-1 to GF-5-1:
in which RG denotes straight chain or branched alkyl having 1 to 7 C atoms, in particular methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl or 2-methylbut-1-yl. The media according to the present invention comprise one or more chiral dopants. Preferably these chiral dopants have an absolute value of the helical twisting power (HTP) in the range of from 1 ^m-1 to 150 ^m-1, preferably in the range of from 10 ^m-1 to 100 ^m-1. In case the media comprise two or more chiral dopants, these may have opposite signs of their HTP-values. This condition is preferred for some specific embodiments, as it allows to compensate the chirality of the respective compounds to some degree and, thus, may be used to compensate various temperature dependent properties of the resulting media in the devices. Generally, however, it is preferred that most, preferably all of the chiral compounds present in the media according to the present invention have the same sign of their HTP-values. Preferably the chiral dopants present in the media according to the instant application are mesogenic compounds and most preferably they exhibit a mesophase on their own. In a preferred embodiment of the present invention, the medium comprises two or more chiral compounds which all have the same algebraic sign of the HTP. The temperature dependence of the HTP of the individual compounds may be high or low. The temperature dependence of the pitch of the medium can be compensated by mixing compounds having different temperature dependencies of the HTP in corresponding ratios. For the optically active component, a multitude of chiral dopants, some of which are commercially available, is available to the person skilled in the art, such as, for example, cholesteryl nonanoate, R- and S-811, R- and S-1011, R- and S-2011, R- and S-3011, R- and S-4011, or CB15 (all Merck KGaA, Darmstadt). Particularly suitable dopants are compounds which contain one or more chiral groups and one or more mesogenic groups, or one or more aromatic or alicyclic groups which form a mesogenic group with the chiral group. Suitable chiral groups are, for example, chiral branched hydrocarbon radicals, chiral ethane diols, binaphthols or dioxolanes, furthermore mono- or polyvalent chiral groups selected from the group consisting of sugar derivatives, sugar alcohols, sugar acids, lactic acids, chiral substituted glycols, steroid derivatives, terpene derivatives, amino acids or sequences of a few, preferably 1-5, amino acids. Preferred chiral groups are sugar derivatives, such as glucose, mannose, galactose, fructose, arabinose and dextrose; sugar alcohols, such as, for example, sorbitol, mannitol, iditol, galactitol or anhydro derivatives thereof, in particular dianhydrohexitols, such as dianhydrosorbide (1,4:3,6-dianhydro-D-sorbide, isosorbide), dianhydromannitol (isosorbitol) or dianhydroiditol (isoiditol); sugar acids, such as, for example, gluconic acid, gulonic acid and ketogulonic acid; chiral substituted glycol radicals, such as, for example, mono- or oligoethylene or propylene glycols, in which one or more CH2 groups are substituted by alkyl or alkoxy; amino acids, such as, for example, alanine, valine, phenylglycine or phenylalanine, or sequences of from 1 to 5 of these amino acids; steroid derivatives, such as, for example, cholesteryl or cholic acid radicals; terpene derivatives, such as, for example, menthyl, neomenthyl, campheyl, pineyl, terpineyl, isolongifolyl, fenchyl, carreyl, myrthenyl, nopyl, geraniyl, linaloyl, neryl, citronellyl or dihydrocitronellyl. The media according to the present invention preferably comprise chiral dopants which are selected from the group of known chiral dopants. Suitable chiral groups and mesogenic chiral compounds are described, for example, in DE 3425503, DE 3534777, DE 3534778, DE 3534779 and DE 3534780, DE 4342280, EP 01038941 and DE 19541820. Examples are also compounds listed in Table F below. Chiral compounds preferably used according to the present invention are selected from the group consisting of the formulae shown below. Particular preference is given to chiral dopants selected from the group consisting of compounds of the following formulae A-I to A-III and A-Ch: in which Ra11, Ra12 and Rb12, independently of one another, denote alkyl having 1 to 15 C atoms, in which, in addition, one or more non-adjacent CH2 groups may each be replaced, independently of one another, by -C(Rz)=C(Rz)-, -C ≡C-, -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O- in such a way that O and/or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may each be replaced by F, Cl, Br, I or CN, preferably alkyl, more preferably n-alkyl, with the proviso that Ra12 is different from Rb12, Ra21 and Ra22, independently of one another, denote alkyl having 1 to 15 C atoms, in which, in addition, one or more non-adjacent CH2 groups may each be replaced, independently of one another, by -C(Rz)=C(Rz)-, -C ≡C-, -O-, - S-, -CO-, -CO-O-, -O-CO- or -O-CO-O- in such a way that O and/or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by F, Cl, Br, I or CN, preferably both are alkyl, more preferably n-alkyl, Ra31, Ra32and Rb32, independently of one another, denote straight-chain or branched alkyl having 1 to 15 C atoms, in which, in addition, one or more non- adjacent CH2 groups may each be replaced, independently of one another, by -C(Rz)=C(Rz)-, -C ≡C-, -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O- in such a way that O and/or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by F, Cl, Br, I or CN, preferably alkyl, more preferably n-alkyl, with the proviso that Ra32 is different from Rb32; Rz denotes H, CH3, F, Cl, or CN, preferably H or F, R8 has one of the meanings of Ra11 given above, preferably alkyl, more preferably n-alkyl having 1 to 15 C atoms, Z8 denotes- C(O)O-, CH2O, CF2O or a single bond, preferably -C(O)O-, A11 is defined as A12 below, or alternatively denotes A12 denotes in which L12 on each occurrence, independently of one another, denotes halogen, CN, or alkyl, alkenyl, alkoxy or alkenyloxy having up to 12 C atoms and in which one or more H atoms are optionally replaced with halogen, preferably methyl, ethyl, Cl or F, particularly preferably F, A21 denotes
A22 has the meanings given for A12 A31 has the meanings given for A11, or alternatively denotes A32 has the meanings given for A12. n2 on each occurrence, identically or differently, is 0, 1 or 2, and n3 is 1, 2 or 3, and r is 0, 1, 2, 3 or 4. Particular preference is given to dopants selected from the group consisting of the compounds of the following formulae: in which m is, on each occurrence, identically or differently, an integer from 1 to 9 and n is, on each occurrence, identically or differently, an integer from 2 to 9. Particularly preferred compounds of formula A are compounds of formula A-III. Further preferred dopants are derivatives of the isosorbide, isomannitol or isoiditol of the following formula A-IV: preferably dianhydrosorbitol, and chiral ethane diols, such as, for example, diphenylethanediol (hydrobenzoin), in particular mesogenic hydrobenzoin derivatives of the following formula A-V: including the (S,S) enantiomers, which are not shown, in which are each, independently of one another, 1,4-phenylene, which may also be mono-, di- or trisubstituted by L, or 1,4-cyclo- hexylene, L is H, F, Cl, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl or alkoxycarbonyloxy having 1-7 carbon atoms, c is 0 or 1, X is CH2 or -C(O)-, Z0 is -COO-, -OCO-, -CH2CH2- or a single bond, and R0 is alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl or alkylcarbonyloxy having 1-12 carbon atoms. Examples of compounds of formula A-IV are:
The compounds of the formula A-IV are described in WO 98/00428. The compounds of the formula A-V are described in GB-A-2,328,207. Very particularly preferred dopants are chiral binaphthyl derivatives, as described in WO 02/94805, chiral binaphthol acetal derivatives, as described in WO 02/34739, chiral TADDOL derivatives, as described in WO 02/06265, and chiral dopants having at least one fluorinated bridging group and a terminal or central chiral group, as described in WO 02/06196 and WO 02/06195. Particular preference is given to chiral compounds of the formula A-VI in which X1, X2, Y1 and Y2 are each, independently of one another, F, Cl, Br, I, CN, SCN, SF5, straight-chain or branched alkyl having from 1 to 25 carbon atoms, which is unsubstituted or monosubstituted or polysubstituted by F, Cl, Br, I or CN and in which, in addition, one or more non-adjacent CH2 groups may each, independently of one another, be replaced by -O-, -S-, -NH-, -NRx-, -CO-, -COO-, -OCO-, -OCOO-, -S-CO-, -CO-S-, -CH=CH- or -C ≡C- in such a way that O and/or S atoms are not bonded directly to one another, a polymerisable group or cycloalkyl or aryl having up to 20 carbon atoms, which may optionally be monosubstituted or polysubstituted by halogen, preferably F, or by a polymerisable group, x1 and x2 are each, independently of one another, 0, 1 or 2, y1 and y2 are each, independently of one another, 0, 1, 2, 3 or 4, B1 and B2 are each, independently of one another, an aromatic or partially or fully saturated aliphatic six-membered ring in which one or more CH groups may each be replaced by N and one or more non-adjacent CH2 groups may each be replaced by O or S, W1 and W2 are each, independently of one another, -Z1-A1-(Z2-A2)m-R, and one of the two is alternatively R1 or A3, but both are not simultaneously H, or U1 and U2 are each, independently of one another, CH2, O, S, CO or CS, V1 and V2 are each, independently of one another, (CH2)n, in which from one to four non-adjacent CH2 groups may each be replaced by O or S, and one of V1 and V2 and, in the case where both are a single bond, n is 1,2 or 3 Z1 and Z2 are each, independently of one another, -O-, -S-, -CO-, -COO-, -OCO-, -O- COO-, -CO-NRx-, -NRx-CO-, -O-CH2-, -CH2-O-, -S-CH2-, -CH2-S-, -CF2-O-, -O-CF2-, -CF2-S-, -S-CF2-, -CH2-CH2-, -CF2-CH2-, -CH2-CF2-, -CF2-CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CH-, -CF=CH-, -CH=CF-, -CF=CF-, -C ≡C-, a combination of two of these groups, where no two O and/or S and/or N atoms are bonded directly to one another, preferably -CH=CH-COO-, or -COO-CH=CH-, or a single bond, Rx denotes alkyl having 1 to 6 C atoms, A1, A2 and A3 are each, independently of one another, 1,4-phenylene, in which one or two non-adjacent CH groups may each be replaced by N, 1,4- cyclohexylene, in which one or two non-adjacent CH2 groups may each be replaced by O or S, 1,3-dioxolane-4,5-diyl, 1,4-cyclohexenylene, 1,4- bicyclo[2.2.2]octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl or 1,2,3,4-tetrahydronaphthalene-2,6-diyl, where each of these groups may be monosubstituted or polysubstituted by L, and in addition A1 can be a single bond, L is a halogen atom, preferably F, CN, NO2, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl or alkoxycarbonyloxy having 1-7 carbon atoms, in which one or more H atoms may each be replaced by F or Cl, m is in each case, independently, 0, 1, 2 or 3, and R and R1 are each, independently of one another, H, F, Cl, Br, I, CN, SCN, SF5, straight-chain or branched alkyl having from 1 or 3 to 25 carbon atoms respectively, which may optionally be monosubstituted or polysubstituted by F, Cl, Br, I or CN, and in which one or more non-adjacent CH2 groups may each be replaced by -O-, -S-, -NH-, -NR0-, -CO-, -COO-, -OCO-, -O- COO-, -S-CO-, -CO-S-, -CH=CH- or -C ≡C-, where no two O and/or S atoms are bonded directly to one another, or a polymerisable group. Particular preference is given to chiral binaphthyl derivatives of the formula A-VI-1 in which ring B, R0 and Z0 are as defined for the formulae A-IV and A-V, and b is 0, 1, or 2, in particular those selected from the following formulae A-VI-1a to A-VI-1c: in which ring B, R0, and Z0 are as defined for the formula A-VI-1, and R0 as defined for formula A-IV or H or alkyl having from 1 to 4 carbon atoms, and b is 0, 1 or 2, and Z0 is, in particular, -OC(O)- or a single bond. The concentration of the one or more chiral dopant(s), in the LC medium is preferably in the range from 0.001 % to 20 %, preferably from 0.05 % to 5 %, more preferably from 0.1 % to 2 %, and, most preferably from 0.5 % to 1.5 %. These preferred concentration ranges apply in particular to the chiral dopant S-4011 or R-4011 (both from Merck KGaA) and for chiral dopants having the same or a similar HTP. For Chiral dopants having either a higher or a lower absolute value of the HTP compared to S- 4011 these preferred concentrations have to be decreased, respectively increased proportionally according to the ratio of their HTP values relatively to that of S-4011. The pitch p of the LC media or host mixtures according to the invention is preferably in the range of from 5 to 50 ^m, more preferably from 8 to 30 ^m and particularly preferably from 10 to 20 ^m. Preferably, the media according to the invention comprise a stabiliser selected from the group of compounds of the formulae ST-1 to ST-22.
in which RST denotes H, an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH2 groups in these radicals may each be replaced, independently of one another, by -C ^C-, -CF2O-, -OCF2-, -CH=CH-, , -CO-O-, -O-CO- in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen, ZST each, independently of one another, denote -CO-O-, -O-CO-, --CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -(CH2)4-, -CH=CH-CH2O-, -C2F4-, -CH2CF2-, -CF2CH2-, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C ≡C- or a single bond, L1 and L2 each, independently of one another, denote F, Cl, CF3 or CHF2, n is an integer from 0 to 12, preferably 5, 6, 7, 8 or 9, very preferably 7, n2, on each occurrence identically or differently, preferably identically, is an integer from 1 to 12, preferably 2, 3, 4, 5, or 6, very preferably 3, and RS on each occurrence identically or differently, preferably identically, denotes alkyl having 1 to 6 C atoms, preferably n-butyl, p denotes 1 or 2, and q denotes 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10. Of the compounds of the formula ST, special preference is given to the compounds of the formulae in which n = 1, 2, 3, 4, 5, 6 or 7, preferably n = 1 or 7 in which n = 1, 2, 3, 4, 5, 6 or 7, preferably n = 3
In the compounds of the formulae ST-3a and ST-3b, n preferably denotes 3. In the compounds of the formula ST-2a, n preferably denotes 7. Very particularly preferred mixtures according to the invention comprise one or more stabilisers from the group of the compounds of the formulae ST-2a-1, ST-3a-1, ST-3b-1, ST-8-1, ST-9-1 and ST-12:
The compounds of the formulae ST-1 to ST-12 are preferably each present in the liquid-crystal mixtures according to the invention in amounts of 0.005 – 0.5%, based on the mixture, very preferably in an amount of 100 ppm, 250 ppm, 500 ppm or 1000 ppm. If the mixtures according to the invention comprise two or more compounds from the group of the compounds of the formulae ST-1 to ST-18, the concentration correspondingly increases to 0.01 – 1% in the case of two compounds, based on the mixtures. However, the total proportion of the compounds of the formulae ST-1 to ST-18, based on the mixture according to the invention, should not exceed 2%.  Other mesogenic compounds which are not explicitly mentioned above can optionally and advantageously also be used in the media in accordance with the present invention. Such compounds are known to the person skilled in the art. In a preferred embodiment of the present invention the medium comprises one or more compounds of formula D in a total concentration of 1 % to 20 %, more preferably 5 % to 15 %, particularly preferably 8 % to 12 %. In a preferred embodiment of the present invention, the liquid-crystalline media comprise a compound of formula T, preferably in a total concentration in the range of from 5 % to 35 %, more preferably 6 % to 30 % and particularly preferably 7 % to 25 %, preferably selected from the formulae T-1a, T-2a and T-3a, very preferably selected from T-1a-5, T-2a-2, T-2a-4 and T-3a-2. In a preferred embodiment, the medium comprises one or more compounds of formula I, preferably of formula I-2 or I-3, in a total concentration in the range of from 1 % to 30 %, more preferably from 2 % to 25 %, very preferably 3% to 20% and particularly preferably from 5 % to 15 %. In a preferred embodiment of the present invention the medium comprises one or more compounds selected from the compounds of the formulae II and GF-1-3 and UI-1-3, preferably of formula II-1 and/or UI-1-3, in a total concentration of 2 % to 35 %, more preferably 3 % to 30 %, particularly preferably 5 % to 25 %. In a preferred embodiment of the present invention the medium comprises one or more compounds of formula IIA-1 in a total concentration of 5 % to 25 %, more preferably 8 % to 20 %, particularly preferably 12 % to 17 %. In a preferred embodiment of the present invention the medium comprises one or more compounds of formula II-1 in an total concentration of 30% or less, more preferably 25% or less, particularly preferably 22% or less. In a preferred embodiment of the present invention the medium comprises one or more compounds selected from the formulae III and IIIa-1 to IIIa-4, preferably III-1 and/or III- 2 and/or IIIa-2 and/or IIIa-3, more preferably III-1f and/or III-1b, and/or III-1h and/or IIIa- 2, in a total concentration of 15 % to 60 % or 65% or 70%, more preferably 20 % to 58 %, particularly preferably 30% to 55% or 35 % to 53 %. In a preferred embodiment of the present invention the medium comprises one or more compounds of formula XII, preferably in a total concentration of 5 % to 30 %, more preferably 8 % to 25 %, particularly preferably 10 % to 20 %. In a preferred embodiment, the medium comprises one or more compounds of the formula D and one or more compounds selected from the group consisting of the formulae I, II and/or IIA, III, XII, T, preferably in a total concentration of 90% or more, more preferably 95%, 96% or 97% or more, very preferably 98% or more and in particular 99% or more. In a preferred embodiment, the medium comprises one or more compounds of the formula D and one or more compounds selected from the group consisting of the formulae I, II and/or IIA, III, XII, T in a total concentration in the range of from 40% to 90% and a total concentration of 10% or more of one or more compounds of the formula IV. In a preferred embodiment, the medium comprises one or more compounds of the formula D and one or more compounds selected from the group consisting of the formulae I, II and/or IIA, III, XII and T in a total concentration in the range of from 40% to 70% and a total concentration of 30% or more of one or more compounds of the formula IV. In a preferred embodiment, the medium comprises one or more compounds of the formula D and one or more compounds selected from the group consisting of the formulae I, II and/or IIA, III, XII and T in a total concentration in the range of from 40% to 60% and a total concentration of 40% or more of one or more compounds of the formula IV. Further preferred embodiments of the present invention, taken alone or in combination with one another, are as follows, wherein some compounds are abbreviated using the acronyms as described in Tables A and B and given in Table C below and n is 1, 2, 3, 4, 5, 6, or 7: - The medium comprises one or more compounds of formula XII-3, preferably of the formula CPU(F.F)-n-S, preferably in a concentration in the range of from 10 to 30%, in articular from 15% to 25%; - The medium comprises one, two, three, four or more compounds of formula III-1, preferably selected from the compounds of the formulae III-1b, III-1f and III-1h; more preferably of III-1b and III-1h; - The medium comprises a compound of formula III-1b, preferably in a total concentration in the range of from 5% to 40%, more preferably 10% to 35%, in particular 15% to 30%; - The medium comprises a compound of formula III-1h, preferably in a total concentration in the range of from 7% to 35%, more preferably 10% to 30%, in particular 12% to 25%; - The medium comprises the compound PPU-TO-S and/or PPTU-TO-S and/or PTPU-TO-S and/or PP(1)TO-n-S; - The medium comprises one or more compounds of formula I-2d, preferably the compounds PGU-2-S and/or PGU-3-S and/or PGU-4-S, and/or CPU-2-S and/or CPU-3-S and/or CPU-4-S; - The medium comprises one or more compounds of formula II-1b, preferably the compounds PTU-4-S and/or PTU-5-S; - The medium comprises one or more compounds of formula PPTU-n-S and/or PTPU-n-S in an total concentration in the range of from 15% to 25%; - The medium comprises one or more compounds of formula PPTU-n-S and/or PTPU-n-S and/or PGTU-n-S in a total concentration in the range of from 15 to 30 %, in which n is 1, 2, 3, 4, 5, or 6; - The medium comprises one or more compounds of formula CPTU-n-S in an total concentration in the range of from 10% to 30%, in particular from 14% to 25%; - The medium comprises one or more compounds of formula ST-3, preferably ST-3a and/or ST-3b, particularly preferably ST-3b-1, in a total concentration in the range of from 0.01 to 1%, preferably from 0.05 to 0.5%, particularly from 0.10 to 0.15%. The liquid-crystal media in accordance with the present invention preferably have a clearing point of 90°C or more, more preferably 100°C or more, more preferably 110°C or more, more preferably 120°C or more, more preferably 130°C or more, particularly preferably 140°C or more and very particularly preferably 150°C or more. The nematic phase of the media according to the invention preferably extends at least from 0°C or less to 90°C or more. It is advantageous for the media according to the invention to exhibit even broader nematic phase ranges, preferably at least from -10°C or less to 120°C or more, very preferably at least from -20°C or less to 140°C or more and in particular at least from -30°C or less to 150°C or more, very particularly preferably at least from -40°C or less to 170°C or more. The Δ ε of the liquid-crystal medium according to the present invention, at 1 kHz and 20°C, is preferably 5 or more, more preferably 7 or more and very preferably 8 or more. The birefringence ( Δn) of the liquid-crystal media according to the present invention, at 589 nm (NaD) and 20°C, is preferably 0.280 or more, more preferably 0.300 or more, even more preferably 0.320 or more, very preferably 0.330 or more and in particular 0.350 or more. The Δn of the liquid-crystal media according to the present invention, at 589 nm (NaD) and 20°C, is preferably in the range from 0.200 to 0.900, more preferably in the range from 0.250 to 0.800, even more preferably in the range from 0.300 to 0.700 and very particularly preferably in the range from 0.350 to 0.600. In a preferred embodiment of the present application, the ^n of the liquid-crystal media in accordance with the present invention is preferably 0.50 or more, more preferably 0.55 or more. The compounds of the formulae I to III in each case include dielectrically positive compounds having a dielectric anisotropy of greater than 3, dielectrically neutral compounds having a dielectric anisotropy of less than 3 and greater than -1.5 and dielectrically negative compounds having a dielectric anisotropy of -1.5 or less. The compounds of the formulae D, I, II and III are preferably dielectrically positive. Preferably, the optical component according to the invention is designed and configured as an optical phase modulator. In a preferred embodiment, the optical component according to the invention is designed and configured for use in a transparent device for phase modulation of IR radiation. In another preferred embodiment, the optical component according to the invention is designed and configured for use in a reflective device for phase modulation of IR radiation. A typical electro-optical modulator comprises conducting, infrared transmitting windows consisting for example of Ge, separated from one another by spacers and having a cell gap in the range of from 1 mm to 5 mm. According to another aspect of the present invention there is provided a LIDAR scanning system as described in WO2018/156643 A1, including a laser configured to emit pulses of light at an operating wavelength in the infrared. The LIDAR scanning system includes a transmit reconfigurable-metasurface configured to reflect an incident pulse of light from the laser as an illumination beam pointing at a selected portion of a field of view, preferably a two dimensional field of view. The pointing of the illumination beam is responsive to a first selected holographic beam steering pattern implemented in the transmit reconfigurable-metasurface. The system further includes a receive reconfigurable-metasurface configured to reflect a return of the illumination beam from the selected portion of the field of view as a relay beam pointing at an optical detector. The pointing of the relay beam is responsive to a second selected holographic beam steering pattern implemented in the receiving reconfigurable metasurface. The system includes an optical detector comprising an array of detector pixels. Each detector pixel includes (i) a photodetector configured to detect light in the return of the illumination beam and (ii) a timing circuit configured to determine a time of flight of the detected light. The optical detector is also configured to output a detection signal indicative of the detected light and a time of flight of the detected light for each pixel of the array. The transmit reconfigurable-metasurface includes a plurality of dynamically adjustable high-Q dielectric resonators arranged on a surface of the reconfigurable-metasurface with inter-element spacing less than the operating wavelength of the laser, where the surface of the reconfigurable-metasurface includes a conducting surface, and the plurality of resonators have a corresponding plurality of adjustable reflection phases providing a dynamically adjustable reflected wave responsive to an incident wave, wherein the conducting surface and the plurality of resonators define a metasurface. Each of the plurality of dielectric resonators includes (i) a pair of regions having high refractive index; and (ii) an electrically-adjustable material disposed in a gap between the regions, wherein the electrically-adjustable material is a liquid crystal material as set forth above and below. According to another aspect of the invention there is provided a reflective spatial light modulator, in particular an LCoS device including the liquid crystal material according to the invention, sandwiched between a transparent glass layer having a transparent electrode, a mirror mounted on a silicon CMOS backplane and PCB. The mirror is divided into a two-dimensional array of individually addressable pixels. Each pixel is individually drivable by a voltage signal to provide a local phase change to at least one polarization component of an optical signal, thereby providing a two-dimensional array of phase manipulating regions. Pre-alignment of the liquid crystal is provided by alignment layers. Said LCoS device is useful for the integration into optical devices. Preferred devices are a wavelength selective switch (WSS), LIDAR scanner, infrared scene projector, as well as other beam steering applications as shown in the article Micallef, F. (2019). Middle infrared beam-steering using liquid crystals for spatial light modulation (Doctoral thesis). https://doi.org/10.17863/CAM.39602 (https://www.repository.cam.ac.uk/handle/1810/292443). In the present application, the expression dielectrically positive describes compounds or components where Δ ε > 3.0, dielectrically neutral describes those where -1.5 ≤ Δ ε ≤ 3.0 and dielectrically negative describes those where Δ ε < -1.5. Δ ε is determined at a frequency of 1 kHz and at 20°C. The dielectric anisotropy of the respective compound is determined from the results of a solution of 10 % of the respective individual compound in a nematic host mixture. If the solubility of the respective compound in the host mixture is less than 10 %, the concentration is reduced to 5 %. The capacitances of the test mixtures are determined both in a cell having homeotropic alignment and in a cell having homogeneous alignment. The cell thickness of both types of cells is approximately 20 µm. The voltage applied is a rectangular wave having a frequency of 1 kHz and an effective value of typically 0.5 V to 1.0 V, but it is always selected to be below the capacitive threshold of the respective test mixture. Δ ε is defined as The host mixture used for the determination of physical constants of pure compounds by extrapolation is ZLI-4792 from Merck KGaA, Germany. The absolute values of the dielectric constants, the birefringence ( ^n) and the rotational viscosity ( γ1) of the compounds are determined from the change in the respective values of the host mixture on addition of the compounds. The concentration in the host is 10 % or in case of insufficient solubility 5 %. The values are extrapolated to a concentration of 100 % of the added compounds. In the examples, the phase sequences of pure compounds are given using the following abbreviations: K: crystalline, N: nematic, SmA: smectic A, SmB: smectic B, I: isotropic. Components having a nematic phase at the measurement temperature of 20°C are measured as such, all others are treated like compounds. The expression threshold voltage in the present application refers to the optical threshold and is quoted for 10 % relative contrast (V10), and the expression saturation voltage refers to the optical saturation and is quoted for 90 % relative contrast (V90), in both cases unless expressly stated otherwise. The capacitive threshold voltage (V0), also called the Freedericks threshold (VFr), is only used if expressly mentioned. The parameter ranges indicated in this application all include the limit values, unless expressly stated otherwise. The different upper and lower limit values indicated for various ranges of properties in combination with one another give rise to additional preferred ranges. Throughout this application, the following conditions and definitions apply, unless expressly stated otherwise. All concentrations are quoted in per cent by weight and relate to the respective mixture as a whole, all temperatures are quoted in degrees Celsius and all temperature differences are quoted in differential degrees. All physical properties are determined in accordance with "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status Nov.1997, Merck KGaA, Germany, and are quoted for a temperature of 20°C, unless expressly stated otherwise. The optical aniso- tropy ( Δn) is determined at a wavelength of 589.3 nm. The dielectric anisotropy ( Δ ε) is determined at a frequency of 1 kHz. The threshold voltages, as well as all other electro- optical properties, are determined using test cells produced at Merck KGaA, Germany. The test cells for the determination of ^ ^ have a cell thickness of approximately 20 µm. The electrode is a circular ITO electrode having an area of 1.13 cm2 and a guard ring. The orientation layers are SE-1211 from Nissan Chemicals, Japan, for homeotropic orientation ( ^ ) and polyimide AL-1054 from Japan Synthetic Rubber, Japan, for homogeneous orientation . The capacitances are determined using a Solatron 1260 frequency response analyser using a sine wave with a voltage of 0.3 Vrms. The light used in the electro-optical measurements is white light. A set-up using a commercially available DMS instrument from Autronic-Melchers, Germany, is used here. The charac- teristic voltages have been determined under perpendicular observation. The threshold (V10), mid-grey (V50) and saturation (V90) voltages have been determined for 10 %, 50 % and 90 % relative contrast, respectively. The liquid-crystalline media are investigated with respect to their properties in the microwave frequency range as described in A. Penirschke et al. “Cavity Perturbation Method for Characterization of Liquid Crystals up to 35 GHz“, 34th European Microwave Conference – Amsterdam, pp.545-548. Compare in this respect also A. Gaebler et al. “Direct Simulation of Material Permittivities …“, 12MTC 2009 – International Instrumentation and Measurement Technology Conference, Singapore, 2009 (IEEE), pp.463-467, and DE 102004029429 A, in which a measurement method is likewise described in detail. The liquid crystal is introduced into a polytetrafluoroethylene (PTFE) or quartz capillary. The capillary has an inner diameter of 0.5mm and an outer diameter of 0.78mm. The effective length is 2.0 cm. The filled capillary is introduced into the centre of the cylindrical cavity with a resonance frequency of 19 GHz. This cavity has a length of 11.5 mm and a radius of 6 mm. The input signal (source) is then applied, and the frequency depending response of the cavity is recorded using a commercial vector network analyser (N5227A PNA Microwave Network Analyzer, Keysight Technologies Inc. USA. For other frequencies, the dimensions of the cavity are adapted correspond- ingly. The change in the resonance frequency and the Q factor between the measurement with the capillary filled with the liquid crystal and the measurement without the capillary filled with the liquid crystal is used to determine the dielectric constant and the loss angle at the corresponding target frequency by means of equations 10 and 11 in the above-mentioned publication A. Penirschke et al., 34th European Microwave Conference – Amsterdam, pp.545-548, as described therein. The values for the components of the properties perpendicular and parallel to the director of the liquid crystal are obtained by alignment of the liquid crystal in a magnetic field. To this end, the magnetic field of a permanent magnet is used. The strength of the magnetic field is 0.35 tesla. Preferred components are phase shifters, varactors, wireless and radio wave antenna arrays, matching circuit adaptive filters and others. In the present application, the term compounds is taken to mean both one compound and a plurality of compounds, unless expressly stated otherwise. All mixtures according to the invention are nematic. The liquid-crystal media according to the invention preferably have nematic phases in preferred ranges given above. The expression have a nematic phase here means on the one hand that no smectic phase and no crystallisation are observed at low temperatures at the corresponding temperature and on the other hand that no clearing occurs on heating from the nematic phase. At high temperatures, the clearing point is measured in capillaries by con- ventional methods. The investigation at low temperatures is carried out in a flow viscometer at the corresponding temperature and checked by storage of bulk samples: The storage stability in the bulk (LTS) of the media according to the invention at a given temperature T is determined by visual inspection.2 g of the media of interest are filled into a closed glass vessel (bottle) of appropriate size placed in a refrigerator at a predetermined temperature. The bottles are checked at defined time intervals for the occurrence of smectic phases or crystallisation. For every material and at each temperature two bottles are stored. If crystallisation or the appearance of a smectic phase is observed in at least one of the two correspondent bottles the test is terminated and the time of the last inspection before the one at which the occurrence of a higher ordered phase is observed is recorded as the respective storage stability. The test is finally terminated after 1000 h, i.e an LTS value of 1000 h means that the mixture is stable at the given temperature for at least 1000 h. The liquid crystals employed preferably have a positive dielectric anisotropy. This is preferably 2 or more, preferably 4 or more, particularly preferably 6 or more and very particularly preferably 10 or more. Furthermore, the liquid-crystal media according to the invention are characterised by high anisotropy values in the microwave range. The birefringence at about 19 GHz is, for example, preferably 0.14 or more, particularly preferably 0.15 or more, particularly preferably 0.20 or more, particularly preferably 0.25 or more and very particularly preferably 0.30 or more. In addition, the birefringence is preferably 0.80 or less. The dielectric anisotropy in the microwave range is defined as The tunability ( τ) is defined as The material quality ( η) is defined as , where the maximum dielectric loss is The tunability τ of the medium according to the invention, measured at 20°C and 19 GHz is 0.250 or more, preferably 0.300 or more, 0.310 or more, 0.320 or more, 0.330 or more, or 0.340 or more, very preferably 0.345 or more and in particular 0.350 or more. The material quality ( η) of the preferred liquid-crystal materials is 6 or more, preferably 8 or more, preferably 10 or more, preferably 15 or more, preferably 17 or more, preferably 20 or more, particularly preferably 25 or more and very particularly preferably 30 or more. In the corresponding components, the preferred liquid-crystal materials have phase shifter qualities of 15°/dB or more, preferably 20°/dB or more, preferably 30°/dB or more, preferably 40°/dB or more, preferably 50°/dB or more, particularly preferably 80°/dB or more and very particularly preferably 100°/dB or more. In some embodiments, however, liquid crystals having a negative value of the dielectric anisotropy can also advantageously be used. The liquid crystals employed are either individual substances or mixtures. They preferably have a nematic phase. The liquid-crystal media in accordance with the present invention may comprise further additives and chiral dopants in the usual concentrations. The total concentration of these further constituents is in the range from 0 % to 10 %, preferably 0.1 % to 6 %, based on the mixture as a whole. The concentrations of the individual compounds used are each preferably in the range from 0.1 % to 3 %. The concentration of these and similar additives is not taken into consideration when quoting the values and concen- tration ranges of the liquid-crystal components and liquid-crystal compounds of the liquid-crystal media in this application. Preferably the media according to the present invention comprise one or more chiral compounds as chiral dopants in order to adjust their cholesteric pitch. Their total concentration in the media according to the instant invention is preferably in the range 0.05 % to 15 %, more preferably from 1 % to 10 % and most preferably from 2 % to 6 %. Optionally the media according to the present invention may comprise further liquid crystal compounds in order to adjust the physical properties. Such compounds are known to the skilled person. Their concentration in the media according to the instant invention is preferably 0 % to 30 %, more preferably 0.1 % to 20 % and most preferably 1 % to 15 %. The response times are given as rise time ( τon) for the time for the change of the relative tuning, respectively of the relative contrast for the electro-optical response, from 0 % to 90 % (t90 – t0), i.e. including the delay time (t10 – t0), as decay time ( τoff) for the time for the change of the relative tuning, respectively of the relative contrast for the electro-optical response, from 100 % back to 10 % (t100 – t10) and as the total response time ( τtotal = τon + τoff), respectively. The liquid-crystal media according to the invention consist of a plurality of compounds, preferably 3 to 30, more preferably 4 to 20 and very preferably 4 to 16 compounds. These compounds are mixed in a conventional manner. In general, the desired amount of the compound used in the smaller amount is dissolved in the compound used in the larger amount. If the temperature is above the clearing point of the compound used in the higher concentration, it is particularly easy to observe completion of the dissolution process. It is, however, also possible to prepare the media in other conventional ways, for example using so-called pre-mixes, which can be, for example, homologous or eutectic mixtures of compounds, or using so-called “multibottle” systems, the constituents of which are themselves ready-to-use mixtures. All temperatures, such as, for example, the melting point T(C,N) or T(C,S), the transition from the smectic (S) to the nematic (N) phase T(S,N) and the clearing point T(N,I) of the liquid crystals, are quoted in degrees Celsius. All temperature differences are quoted in differential degrees. In the present invention and especially in the following examples, the structures of the mesogenic compounds are indicated by means of abbreviations, also referred to as acronyms. In these acronyms, the chemical formulae are abbreviated as follows using Tables A to C below. All groups CnH2n+1, CmH2m+1 and ClH2l+1, and CnH2n-1, CmH2m-1 and ClH2l-1 denote straight-chain alkyl or alkylene, respectively, in each case having n, m or l C atoms, wherein n and m, independently are 1, 2, 3, 4, 5, 6 or 7 and l is 1, 2 or 3. Table A lists the codes used for the ring elements of the core structures of the compounds, while Table B shows the linking groups and end groups. Table C shows illustrative structures of compounds with their respective abbreviations. Table A: Ring elements
Table B: End groups Left-hand side Right-hand side Used alone -n- CnH2n+1- -n -CnH2n+1 Used in combination with others -…K… in which n and m each denote integers, and the three dots “...” are placeholders for other abbreviations from this table. Branched lateral groups are numbered starting from the position next to the ring (1) where the longest chain is selected, the smaller number indicating the length of the branch and the superscript number in brackets indicates the position of the branch, for example: The following table shows illustrative structures together with their respective abbreviations. These are shown in order to illustrate the meaning of the rules for the abbreviations. They furthermore represent compounds which are preferably used. Table C: Illustrative structures The following illustrative structures are examples as well as compounds, which are preferably additionally used in the media: in which m and n, identically or differently, are 1, 2, 3, 4, 5, 6 or 7. Preferably, the medium according to the invention comrises one or more compounds selected from the compounds of Table C. The following table, Table D, shows illustrative compounds which can be used as alternative stabilisers in the mesogenic media in accordance with the present invention. The total concentration of these and similar compounds in the media is preferably 5 % or less. Table D
In a preferred embodiment of the present invention, the mesogenic media comprise one or more compounds selected from the group of the compounds from Table D. The following table, Table E, shows illustrative compounds which can preferably be used as chiral dopants in the mesogenic media in accordance with the present invention. Table E
In a preferred embodiment of the present invention, the mesogenic media comprise one or more compounds selected from the group of the compounds of Table E. The mesogenic media in accordance with the present application preferably comprise two or more, preferably four or more, compounds selected from the group consisting of the compounds from the above tables. Unless indicated otherwise, parts or per cent data denote parts by weight or per cent by weight. Above and below: Vo denotes threshold voltage, capacitive [V] at 20°C, ne denotes extraordinary refractive index at 20°C and 589 nm, no denotes ordinary refractive index at 20°C and 589 nm, Δn denotes optical anisotropy at 20°C and 589 nm, denotes dielectric permittivity perpendicular to the director at 20°C and 1 kHz, denotes dielectric permittivity parallel to the director at 20°C and 1 kHz, Δ ε denotes dielectric anisotropy at 20°C and 1 kHz, clp., T(N,I) denotes clearing point [°C], γ1 denotes rotational viscosity measured at 20°C [mPa ^s], K1 denotes elastic constant, "splay" deformation at 20°C [pN], K2 denotes elastic constant, "twist" deformation at 20°C [pN], K3 denotes elastic constant, "bend" deformation at 20°C [pN], Kavg. denotes average elastic constant defined a LTS denotes low-temperature stability (nematic phase), determined in test cells or in the bulk, as specified. Unless explicitly noted otherwise, all values indicated in the present application for temperatures, such as, for example, the melting point T(C,N), the transition from the smectic (S) to the nematic (N) phase T(S,N) and the clearing point T(N,I) or clp., are indicated in degrees Celsius (°C). M.p. denotes melting point . Furthermore, Tg = glass state, C = crystalline state, N = nematic phase, S = smectic phase and I = isotropic phase. The numbers between these symbols represent the transition temperatures. The term "threshold voltage" for the present invention relates to the capacitive threshold (V0), also called the Freedericksz threshold, unless explicitly indicated otherwise. In the examples, as is generally usual, the optical threshold can also be indicated for 10 % relative contrast (V10). The display used for measurement of the capacitive threshold voltage consists of two plane-parallel glass outer plates at a separation of 20 µm, which each have on the insides an electrode layer and an unrubbed polyimide alignment layer on top, which cause a homeotropic edge alignment of the liquid-crystal molecules. The so-called "HTP" denotes the helical twisting power of an optically active or chiral substance in an LC medium (in µm). Unless indicated otherwise, the HTP is measured in the commercially available nematic LC host mixture MLD-6260 (Merck KGaA) at a temperature of 20°C. The Clearing point is measured using the Mettler Thermosystem FP900. The optical anisotropy ( ^n) is measured using an Abbe Refractometer H005 (Natrium-spectral lamp Na10 at 589nm, 20 °C). The dielectric anisotropy ( Δ ε) is measured using an LCR- Meter E4980A/Agilent (G005) at 20°C ( ^-parallel-cells with JALS 2096-R1). The turn on voltage (V0) is measured using an LCR-Meter E4980A/Agilent (G005) at 20°C ( ε- parallel-cells with JALS 2096-R1). The rotational viscosity ( γ1) is measured using a TOYO LCM-2 (0002) at 20°C (gamma 1 negative cells with JALS-2096-R 1 ). The elastic constant (K1, splay) is measured using an LCR-Meter E4980A/Agilent (G005) at 20°C ( ε parallel-cells with JALS 2096-R1). K3: The elastic constant (K3, bend) is measured using an LCR-Meter E4980A/Agilent (G005) at 20°C ( ^-parallel-cells with JALS 2096-R1). Unless explicitly noted otherwise, all concentrations in the present application are indicated in per cent by weight and relate to the corresponding mixture as a whole, comprising all solid or liquid-crystalline components, without solvents. All physical properties are determined in accordance with "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status November 1997, Merck KGaA, Germany, and apply for a temperature of 20°C, unless explicitly indicated otherwise. Examples The present invention is illustrated in detail by the following non-restrictive working examples. Synthesis Examples The following abbreviations are used: RT room temperature MTB ether tert-butyl methyl ether DABCO 1,4-Diazabicyclo[2.2.2]octane dist. Distilled RP reversed phase THF tetrahydrofuran XPhos 2-Dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl XPhos Pd G2 Chloro(2 dicyclohexylphosphino 2′,4′,6′ triisopropyl 1,1′ biphenyl)[2 (2′ amino 1,1′ biphenyl)palladium (II) Synthesis Example 1: 7-((3,5-Difluoro-4-isothiocyanatophenyl)ethynyl)-3-pentyl-1,2- dihydronaphthalene Step 1.1: 7-Bromo-3-pentyl-1,2-dihydronaphthalene A solution of 6-bromo-3,4-dihydronaphthalen-2-yl trifluoromethane sulfonate (CAS 1013891-56-9) (12.0 g, 34 mmol) in THF (150 ml) is treated with cobalt(III)- acetylacetonate (360 mg, 1.01 mmol) at -20°C under argon atmosphere. Pentyl magnesium bromide (25 ml of a 2M solution in diethyl ether) is added dropwise at -20°C, and the reaction mixture is stirred for 2 h at -20°C. It is then quenched with ice water (100 ml), acidified with hydrochloric acid (2N) and extracted with MTB ether twice. The combined organic phases are dried (sodium sulfate), filtered and concentrated in vacuo. The residue is purified by flash chromatography (silica gel, eluent heptane) followed by RP chromatography (eluent acetonitrile) to give 7-bromo-3- pentyl-1,2-dihydronaphthalene as a colorless oil. Step 1.2: 2,6-Difluoro-4-((6-pentyl-7,8-dihydronaphthalen-2-yl)ethynyl)aniline
A solution of 7-bromo-3-pentyl-1,2-dihydronaphthalene (3.2 g, 11 mmol) and 4-ethynyl- 2,6-difluoroaniline (CAS 753501-37-0) (1.9 g, 12 mmol) in THF (25 ml) and diisopropylamine (25 ml) is treated with XPhos (11 mg, 0.02 mmol), XPhos Pd G2 (18 mg, 0.02 mmol) and copper(I) iodide (2.2 mg, 0.01 mmol) at 50°C under argon atmosphere, and the reaction mixture is stirred for 4 h at reflux temperature. It is allowed to cool down to room temperature and quenched with dist. water and MTB ether. The aqueous phase is separated and extracted with MTB ether, and the combined organic phases are washed with brine and concentrated in vacuo. The residue is purified by flash chromatography (silica gel, eluent heptane/chlorobutane) to give 2,6-difluoro-4-((6-pentyl-7,8-dihydronaphthalen-2-yl)ethynyl)aniline as a colorless solid. Step 1.3: 7-((3,5-Difluoro-4-isothiocyanatophenyl)ethynyl)-3-pentyl-1,2- dihydronaphthalene Thiophosgene (0.9 ml, 11 mmol) is slowly added to a solution of 2,6-difluoro-4-((6- pentyl-7,8-dihydronaphthalen-2-yl)ethynyl)aniline (3.0 g, 9 mmol) and DABCO (3.0 g, 27 mmol) in dichloromethane (50 ml) at 0°C under argon atmosphere, and the reaction mixture is stirred at room temperature for 1 h. Then it is quenched with dist. water (1 ml), filtered over silica gel, washed with dichloromethane, and concentrated in vacuo. The residue is purified by flash chromatography (silica gel, eluent heptane/chlorobutane) and subsequent crystallization (heptane and heptane/acetone) to give light yellow crystals of 7-((3,5-difluoro-4-isothiocyanatophenyl)ethynyl)-3-pentyl- 1,2-dihydronaphthalene. Phase sequence: K 75 N 84 I Δn = 0.4218 Δ ε= 20.4 Synthesis Example 2: 7-((3,5-Difluoro-4-isothiocyanatophenyl)ethynyl)-3-(pent-1-yn-1- yl)-1,2-dihydronaphthalene Step 2.1: 7-Bromo-3-(pent-1-yn-1-yl)-1,2-dihydronaphthalene A solution of 6-bromo-3,4-dihydronaphthalen-2-yl trifluoromethanesulfonate (CAS 1013891-56-9) (9.5 g, 27 mmol) and pent-1-yne (1.9 g, 28 mmol) in THF (60 ml) and triethylamine (30 ml) is treated with bis(triphenylphosphine)palladium(II) chloride (187 mg, 0.3 mmol) and copper(I) iodide (56 mg, 0.3 mmol) under argon atmosphere, and the reaction mixture is stirred for 2 h at 40°C. It is allowed to cool down to room temperature and quenched with dist. water and MTB ether. The aqueous phase is separated and extracted with MTB ether, and the combined organic phases are washed with brine, dried (sodium sulfate) and concentrated in vacuo. The residue is purified by flash chromatography (silica gel, eluent heptane) followed by RP chromatography (eluent acetonitrile) to give 7-bromo-3-(pent-1-yn-1-yl)-1,2- dihydronaphthalene as a yellow oil. Step 2.2: 2,6-Difluoro-4-((6-(pent-1-yn-1-yl)-7,8-dihydronaphthalen-2-yl)ethynyl)aniline To a solution of 7-bromo-3-(pent-1-yn-1-yl)-1,2-dihydronaphthalene (5.6 g, 20 mmol) and 4-ethynyl-2,6-difluoroaniline (CAS 753501-37-0) (3.1 g, 20 mmol) in THF (45 ml) and diisopropylamine (45 ml), XPhos (19 mg, 0.04 mmol), XPhos Pd G2 (32 mg, 0.04 mmol) and copper(I) iodide (3.8 mg, 0.02 mmol) are added at 50°C under argon atmosphere, and the reaction mixture is stirred for 4 h at reflux temperature. It is allowed to cool down to room temperature and quenched with dist. water and MTB ether. The aqueous phase is separated and extracted with MTB ether, and the combined organic phases are washed with brine and concentrated in vacuo. The residue is purified by flash chromatography (silica gel, eluent heptane/chlorobutane) to give 2,6-difluoro-4-((6-(pent-1-yn-1-yl)-7,8-dihydronaphthalen-2-yl)ethynyl)aniline as a colorless solid. Step 2.3: 7-((3,5-Difluoro-4-isothiocyanatophenyl)ethynyl)-3-(pent-1-yn-1-yl)-1,2- dihydronaphthalene Thiophosgene (1.8 ml, 23 mmol) is slowly added to a solution of 2,6-difluoro-4-((6- (pent-1-yn-1-yl)-7,8-dihydronaphthalen-2-yl)ethynyl)aniline (5.8 g, 17 mmol) and DABCO (5.0 g, 45 mmol) in dichloromethane (80 ml) at 0°C under argon atmosphere, and the reaction mixture is stirred at room temperature overnight. Then it is quenched with dist. water (2 ml), filtered over silica gel, washed with dichloromethane and concentrated in vacuo. The residue is purified by flash chromatography (silica gel, eluent heptane/chlorobutane) and subsequent crystallization (heptane/acetone) to give yellow crystals of 7-((3,5-difluoro-4-isothiocyanatophenyl)ethynyl)-3-(pent-1-yn-1-yl)- 1,2-dihydronaphthalene. Phase sequence: K 89 N (80) I Δn = 0.5352 Δ ε= 20.7 Synthesis Example 3: 7-(3,5-Difluoro-4-isothiocyanatophenyl)-3-((4-pentylphenyl)- ethynyl)-1,2-dihydronaphthalene Step 3.1: 7-Bromo-3-((4-pentylphenyl)ethynyl)-1,2-dihydronaphthalene A solution of 6-bromo-3,4-dihydronaphthalen-2-yl trifluoromethanesulfonate (CAS 1013891-56-9) (5.5 g, 15 mmol) and 1-ethynyl-4-pentylbenzene (CAS 79887-10-8) (2.7 g, 16 mmol) in THF (50 ml) and triethylamine (25 ml) is treated with bis(triphenylphosphine)palladium(II) chloride (108 mg, 0.2 mmol) and copper(I) iodide (32 mg, 0.2 mmol) under argon atmosphere, and the reaction mixture is stirred for 2 h at 50°C. It is allowed to cool down to room temperature and quenched with dist. water and MTB ether. The aqueous phase is separated and extracted with MTB ether, and the combined organic phases are washed with brine, dried (sodium sulfate) and concentrated in vacuo. The residue is purified by flash chromatography (silica gel, eluent heptane/chlorobutane) and crystallization (isopropanol) to give colorless crystals of 7-bromo-3-((4-pentylphenyl)ethynyl)-1,2-dihydronaphthalene. Step 3.2: 2,6-Difluoro-4-(6-((4-pentylphenyl)ethynyl)-7,8-dihydronaphthalen-2-yl)aniline A solution of potassium carbonate (2.9 g, 21 mmol) in dist. water (15 ml) is added to a solution of 7-bromo-3-((4-pentylphenyl)ethynyl)-1,2-dihydronaphthalene (4.7 g, 12 mmol) in THF (80 ml) at room temperature under argon atmosphere. The mixture is heated to 60°C and treated with di-(1-adamantyl)-n-butylphosphine (50 mg, 0.14 mmol) and tris(dibenzylidene-acetone)dipalladium(0) (70 mg, 0.08 mmol). Then a solution of 2,6-difluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline (CAS 939968-08-8) (3.5 g, 12 mmol) in THF (20 ml) is slowly added, and the mixture is stirred at reflux temperature overnight. Then it is allowed to cool to room temperature and quenched with brine and MTB-ether. The aqueous phase is separated and washed with MTB- ether, and the combined organic phases are washed with brine, dried (sodium sulfate) and concentrated in vacuo. The residue is purified by flash chromatography (silica gel, eluent heptane/chlorobutane) and crystallization (toluene) to give 2,6-difluoro-4-(6-((4- pentylphenyl)ethynyl)-7,8-dihydronaphthalen-2-yl)aniline as a pale yellow solid. Step 3.3: 7-(3,5-Difluoro-4-isothiocyanatophenyl)-3-((4-pentylphenyl)ethynyl)-1,2- dihydronaphthalene Thiophosgene (0.9 ml, 11 mmol) is slowly added to a solution of 2,6-difluoro-4-(6-((4- pentylphenyl)ethynyl)-7,8-dihydronaphthalen-2-yl)aniline (3.7 g, 9 mmol) and DABCO (3.0 g, 27 mmol) in dichloromethane (50 ml) at 0°C under argon atmosphere, and the reaction mixture is stirred for 2 h at room temperature. Then it is quenched with dist. water (1 ml), filtered over silica gel, washed with dichloromethane and concentrated in vacuo. The residue is purified by flash chromatography (silica gel, eluent heptane/chlorobutane) and crystallization (heptane) to give 7-(3,5-difluoro-4- isothiocyanatophenyl)-3-((4-pentylphenyl)ethynyl)-1,2-dihydronaphthalene as a pale yellow solid. Phase sequence: K 97 N 239 I. Δn = 0.5362 Δ ε= 20.2 Synthesis Example 4: 3-((3,5-Difluoro-4-isothiocyanatophenyl)ethynyl)-7-pentyl-1,2- dihydronaphthalene Step 4.1: 4-((6-Bromo-3,4-dihydronaphthalen-2-yl)ethynyl)-2,6-difluoroaniline To a solution of 6-bromo-3,4-dihydronaphthalen-2-yl trifluoromethanesulfonate (CAS 1013891-56-9) (9.0 g, 24 mmol) and 4-ethynyl-2,6-difluoroaniline (CAS 753501-37-0) (3.8 g, 24 mmol) in THF (90 ml) and triethylamine (45 ml), bis(triphenylphosphine)palladium(II) chloride (180 mg, 0.26 mmol) and copper(I) iodide (50 mg, 0.26 mmol) are added under argon atmosphere, and the reaction mixture is stirred at 50°C overnight. It is allowed to cool down to room temperature and quenched with dist. water and MTB ether. The aqueous phase is separated and extracted with MTB ether, and the combined organic phases are washed with brine, dried (sodium sulfate) and concentrated in vacuo. The residue is purified by flash chromatography (silica gel, eluent chlorobutane) to give 4-((6-bromo-3,4-dihydronaphthalen-2- yl)ethynyl)-2,6-difluoroaniline as a pale brown solid. Step 4.2: 2,6-Difluoro-4-((6-pentyl-3,4-dihydronaphthalen-2-yl)ethynyl)aniline To a solution of 4-((6-bromo-3,4-dihydronaphthalen-2-yl)ethynyl)-2,6-difluoroaniline (8.1 g, 23 mmol) in THF (100 ml), potassium phosphate monohydrate (11.0 g, 45 mmol), bis(dibenzylidene-acetone)palladium(0) (130 mg, 0.22 mmol) and 2- dicyclohexylphosphino-2’,6’-dimethoxybiphenyl (190 mg, 0.45 mmol) are added under argon atmosphere. Then a solution of pentylboronic acid (5.5 g, 45 mmol) in THF (10 ml) is added, and the reaction mixture is stirred at reflux temperature overnight. It is allowed to cool to room temperature and quenched with dist. water and MTB-ether. The aqueous phase is separated and washed with MTB-ether, and the combined organic phases are washed with brine, dried (sodium sulfate) and concentrated in vacuo. The residue is purified by flash chromatography (silica gel, eluent chlorobutane) to give yellow crystals of 2,6-difluoro-4-((6-pentyl-3,4-dihydronaphthalen-2- yl)ethynyl)aniline. Step 4.3: 3-((3,5-Difluoro-4-isothiocyanatophenyl)ethynyl)-7-pentyl-1,2- dihydronaphthalene Thiophosgene (2.7 g, 23 mmol) is slowly added to a solution of 2,6-difluoro-4-((6- pentyl-3,4-dihydronaphthalen-2-yl)ethynyl)aniline (6.4 g, 18 mmol) and DABCO (5.2 g, 46 mmol) in dichloromethane (100 ml) at 0°C under argon atmosphere, and the reaction mixture is stirred at room temperature overnight. Then it is quenched with dist. water, filtered over silica gel, washed with dichloromethane and concentrated in vacuo. The residue is purified by flash chromatography (silica gel, eluent heptane) and subsequent crystallization (heptane) to give yellow crystals of 3-((3,5-difluoro-4- isothiocyanatophenyl)ethynyl)-7-pentyl-1,2-dihydronaphthalene. Phase sequence: K 57 N (46) I. Δn = 0.4425 Δ ε= 15.9 In analogy to Synthesis Examples 1 to 4 the following compounds are obtained:
Mixture Examples Host mixture H1 has the following composition: The following example mixtures are prepared from host mixture H1 and compounds according to the invention as indicated in the following tables. Comparative example C1 Example Mixture M1 Example Mixture M1 differs from the Comparative Example C1 in that the compound PTU-5-S has been replaced with the compound Np(2H)TU-5-S according to the invention. This has the effect that the clearing temperature, the dielectric loss, the tunability and the figure-of-merit are all significantly improved. Example Mixture M2 Example Mixture M3 Example Mixture M4 Example Mixture M5 Example Mixture M6 Example Mixture M7 Example Mixture M8

Claims

Patent Claims 1. A compound of formula D in which RD denotes H, straight-chain alkyl having 1 to 12 C atoms or branched alkyl having 2 to 12 C atom, or straight-chain alkenyl having 2 to 12 C atoms, or branched alkenyl having 3 to 12 C atoms, or straight-chain alkynyl having 2 to 12 C atoms or branched alkynyl having 4 to 12 C atoms, in which one or more CH2-groups may be replaced by , , , and where one or more non-adjacent CH2-groups may be replaced by O, or denotes a group RP, RP denotes halogen, CN, NCS, RF-, RF-O- or RF-S-, wherein RF denotes fluorinated alkyl having 1 to 9 C atoms, ZD1, ZD2, ZD3 and ZD4, identically or differently, denote -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -N=N-, -C=N-N=C-, -CH=N-, -N=CH-, -C ≡C-, -C ≡C-C ≡C-, or a single bond, where ZD1 alternatively denotes -O-, -S-, -CO-O-, -O-CO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -(CH2)3-, -(CH2)4-, -C2F4-, -CH2CF2-, -CF2CH2 -, -CH=CH-CH2O-, -CH=CH-CO-O-, -OCH2-CH=CH-, or -O-CO-CH=CH-, XD denotes -C ≡C-CN, -NCS, or -C ≡C-NCS, , identically or differently, denote a radical selected from the following groups: a) the group consisting of 1,4-phenylene, 1,4-naphthylene, and 2,6-naphthylene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L, b) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, tetralin- 2,6-diyl, tetralin-5,8-diyl, decalin-2,6-diyl, bicyclo[1.1.1]pentane-1,3-diyl, 4,4´- bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl, and spiro[3.3]heptane-2,6-diyl, in which one or two CH groups may be replaced by N, one or more non-adjacent CH2 groups may be replaced by -O- and/or -S- and in which one or more H atoms may be replaced by L, c) the group consisting of thiophene-2,5-diyl, thieno[3,2-b]thiophene-2,5-diyl, and selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L, n which one or more H atoms are optionally replaced by L, L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy each having 1 to 12 C atoms, t1, t2, t3 and t4, identically or differently, are 0,1 or 2, where t1 + t2 + t3 + t4 is 1, 2 or 3. 2. The compound according to claim 1, wherein the compound is selected from the compounds of the formulae D-1 and D-2 in which RD ZD2, ZD4 and XD have the meanings given in claim 1, and t2 is 0, 1 or 2, t4 is 0 or 1, and t2+t4 is 1, 2 or 3. 3. The compound according to claim 2, wherein ZD2 and ZD4, identically or differently, denote -CH=CH-, -CF=CF-, -C ≡C-, or a single bond. 4. The compound according to one or more of claims 1 to 3, wherein
in which RL, on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, or cycloalkyl having 3 to 5 C atoms, where alternatively denotes in which W denotes N, C-H, C-F or C-Cl, and Y1 and Y2, identically or differently, denote H, Cl, F, methyl or ethyl. 5. The compound according to one or more of claims 1 to 4, wherein XD denotes -NCS. 6. A liquid crystal medium comprising one or more compounds of formula D according to one or more of claims 1 to 5. 7. The liquid crystal medium according to claim 6, wherein the medium additionally comprises one or more compounds selected from the group of compounds of the formulae I, II and III: in which R1 denotes H, non-fluorinated alkyl having 1 to 12 C atoms, or non- fluorinated alkenyl having 2 to 12 C atoms, in which one or more CH2- groups may be replaced by , where one or more non-adjacent CH2-groups may be replaced by O, n is 0, 1 or 2, and , on each occurrence, independently of one another, , in which RL, on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, or denot n which one or more H atoms may be replaced by alkyl having 1 to 6 C atoms or F,
R2 denotes H, non-fluorinated alkyl having 1 to 12 C atoms, or non-fluorinated alkenyl having 2 to 12 C atoms, in which one or more CH2-groups may be replaced , where one or more non-adjacent CH2-groups may be replaced by O, Z21 denotes trans-CH=CH-, trans-CF=CF- or -C≡C-, and , , in which RL, on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, or denotes , in which one or more H atoms may be replaced by alkyl having 1 to 6 C atoms or F, in which RL, on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, or denotes in which one or more H atoms may be replaced by alkyl having 1 to 6 C atoms or F; R3 denotes H, non-fluorinated alkyl or non-fluorinated alkoxy having 1 to 17 C atoms, or non-fluorinated alkenyl, non-fluorinated alkenyloxy or non-fluorinated alkoxyalkyl having 2 to 15 C atoms, in which one or more CH2-groups may be replaced , one of Z31 and Z32 denotes trans-CH=CH-, trans-CF=CF- or -C≡C- and the other one, independently thereof, denotes -C≡C-, trans-CH=CH-, trans- CF=CF- or a single bond, and independently of one another, denote r n which RL , on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, in which one or more H atoms may be replaced by alkyl having 1 to 6 C atoms or F, and wherein alternatively denotes
identically or differently, denotes H or alkyl having 1 to 6 C atoms, or denotes , in which one or more H atoms may be replaced by alkyl having 1 to 6 C atoms or F. 8. The liquid crystal medium according to claim 6 or 7, wherein the medium comprises one or more compounds selected from the group of compounds of the formulae I-1 to I-5
in which L1, L2 and L3 on each occurrence, identically or differently, denote H or F, and have the meanings given for formula I in claim 7. 9. The liquid crystal medium according to one or more of claims 6 to 8, wherein the medium comprises one or more compounds selected from the group of compounds of the formulae II-1 to II-3 in which have the meanings given in claim 7 for formula II. 10. The liquid crystal medium according to one or more of claims 6 to 9, wherein the medium comprises one or more compounds of formula III selected from the compounds of the formulae III-1 to III-6
in which Z31 and Z32 independently of one another denote trans-CH=CH- or trans- CF=CF-, preferably trans-CH=CH-, and in formula III-6 alternatively one of Z31 and Z32 may denote -C≡C- and the other groups have the meaning given in claim 1 under formula III, R3 denotes non-fluorinated alkyl or alkoxy having 1 to 7 C atoms or non-fluorinated alkenyl having 2 to 7 C atoms, and one of and the others, independently of one another, denote
where alternatively denotes 11. The medium according to one or more of claims 6 to 10, wherein the medium comprises one or more compounds selected from the formulae IIIa-1, IIIa-2, IIIa-3 and IIIa-4: in which R3 has the meanings defined for formula III in claim 7. 12. The liquid crystal medium according to one or more of claims 6 to 11, wherein the medium comprises one or more compounds of formula UI in which RU denotes H, straight-chain or branched non-fluorinated alkyl having 1 to 12 C atoms or non-fluorinated alkenyl having 2 to 12 C atoms, in which one or more CH2-groups may be replaced by , where one or more non-adjacent CH2-groups may be replaced by O, or denotes a group RP, RP denotes halogen, CN, NCS, fluorinated alkyl, RF-O- or RF-S-, wherein RF denotes fluorinated alkyl or fluorinated alkenyl having up to 9 C atoms, ZU1 denotes -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C ≡C- or -C ≡C-C ≡C-, XU1, XU2, identically or differently, denote Cl or F, denote a radical selected from the following groups: a) the group consisting of 1,4-phenylene, 1,4-naphthylene, and 2,6-naphthylene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L, b) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, tetralin- 2,6-diyl, tetralin-5,8-diyl, decalin-2,6-diyl, bicyclo[1.1.1]pentane-1,3-diyl, 4,4´- bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl, and spiro[3.3]heptane-2,6-diyl, in which one or two CH groups may be replaced by N, one or more non-adjacent CH2 groups may be replaced by -O- and/or -S- and in which one or more H atoms may be replaced by L, c) the group consisting of thiophene-2,5-diyl, thieno[3,2-b]thiophene-2,5-diyl, selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L, L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy each having 1 to 12 C atoms, u is 0 or 1, v is 0 or 1, where the compounds of the formula UI are excluded from the compounds of the formulae I, II and III of claim 7. 13. An electronic component comprising a first substrate and a second substrate facing each other, a liquid crystal layer sandwiched between said substrates, an electrode provided on each substrate or two electrodes provided on only one of the substrates for supplying an electric potential across said liquid crystal layer to drive liquid crystals in a predetermined configuration, characterised in that the liquid crystal layer comprises the liquid crystal medium according to one or more of claims 6 to 12. 14. The component according to claim 13, wherein the component is configured for use in high-frequency technology. 15. The component according to claim 14, wherein the component is a liquid-crystal based antenna element, a phase shifter, a tunable filter, a tunable metamaterial structure, a matching network or a varactor. 16. A microwave antenna array, characterised in that it comprises one or more components according to claim 14 or 15. 17. The component according to claim 13, wherein the component is a transmissive or a reflective spatial light modulator.
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