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WO2018104279A1 - Liquid crystal medium and liquid crystal device - Google Patents

Liquid crystal medium and liquid crystal device Download PDF

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Publication number
WO2018104279A1
WO2018104279A1 PCT/EP2017/081471 EP2017081471W WO2018104279A1 WO 2018104279 A1 WO2018104279 A1 WO 2018104279A1 EP 2017081471 W EP2017081471 W EP 2017081471W WO 2018104279 A1 WO2018104279 A1 WO 2018104279A1
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Prior art keywords
phe
phel
compounds
formula
independently
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PCT/EP2017/081471
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French (fr)
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Simon SIEMIANOWSKI
Konstantin Schneider
Peter Best
Matthias Bremer
Jana JEHN
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Merck Patent Gmbh
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Priority to DE112017006197.0T priority Critical patent/DE112017006197T5/en
Publication of WO2018104279A1 publication Critical patent/WO2018104279A1/en

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    • C—CHEMISTRY; METALLURGY
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    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/02—Liquid crystal materials characterised by optical, electrical or physical properties of the components, in general
    • C09K19/0258—Flexoelectric
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/062—Non-steroidal liquid crystal compounds containing one non-condensed benzene ring
    • C—CHEMISTRY; METALLURGY
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
    • C09K19/10—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings
    • C09K19/20—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings linked by a chain containing carbon and oxygen atoms as chain links, e.g. esters or ethers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K2019/0444—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit characterized by a linking chain between rings or ring systems, a bridging chain between extensive mesogenic moieties or an end chain group
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    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K2019/0444—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit characterized by a linking chain between rings or ring systems, a bridging chain between extensive mesogenic moieties or an end chain group
    • C09K2019/0466—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit characterized by a linking chain between rings or ring systems, a bridging chain between extensive mesogenic moieties or an end chain group the linking chain being a -CF2O- chain
    • C—CHEMISTRY; METALLURGY
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
    • C09K19/30—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing saturated or unsaturated non-aromatic rings, e.g. cyclohexane rings
    • C09K19/3001—Cyclohexane rings
    • C09K19/3003—Compounds containing at least two rings in which the different rings are directly linked (covalent bond)
    • C09K2019/3009—Cy-Ph
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
    • C09K19/30—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing saturated or unsaturated non-aromatic rings, e.g. cyclohexane rings
    • C09K19/3001—Cyclohexane rings
    • C09K19/3003—Compounds containing at least two rings in which the different rings are directly linked (covalent bond)
    • C09K2019/301—Cy-Cy-Ph
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
    • C09K19/30—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing saturated or unsaturated non-aromatic rings, e.g. cyclohexane rings
    • C09K19/3001—Cyclohexane rings
    • C09K19/3003—Compounds containing at least two rings in which the different rings are directly linked (covalent bond)
    • C09K2019/3016—Cy-Ph-Ph
    • C—CHEMISTRY; METALLURGY
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
    • C09K19/30—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing saturated or unsaturated non-aromatic rings, e.g. cyclohexane rings
    • C09K19/3001—Cyclohexane rings
    • C09K19/3059—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
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
    • C09K19/30—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing saturated or unsaturated non-aromatic rings, e.g. cyclohexane rings
    • C09K19/3001—Cyclohexane rings
    • C09K19/3066—Cyclohexane rings in which the rings are linked by a chain containing carbon and oxygen atoms, e.g. esters or ethers
    • C09K19/3068—Cyclohexane rings in which the rings are linked by a chain containing carbon and oxygen atoms, e.g. esters or ethers chain containing -COO- or -OCO- groups
    • C09K2019/3075—Cy-COO-Ph

Definitions

  • the invention relates to a compound of formula I, R 11 -MG 11 -X 11 -Sp 11 -X 12 -MG 12 -R 12 I wherein R 11 , R 22 , MG 11 , MG 12 , Sp 11 , X 11 and X 12 have one of the meanings as given herein below.
  • the invention further relates to method of production of a compound of formula I, to the use of said compounds in LC media and to LC media comprising one or more compounds of formula I.
  • the invention relates to a method of production of such LC media, to the use of such media in LC devices, in particular in flexoelectric LC devices and to a flexoelectric LC device comprising a LC medium according to the present invention.
  • Background and Prior Art The flexoelectric effect is described, for example, by Chandrasekhar, "Liquid Crystals", 2 nd edition, Cambridge University Press (1992) and P.G. deGennes et al., "The Physics of Liquid Crystals", 2 nd edition, Oxford Science Publications (1995).
  • Flexoelectric devices utilizing the flexoelectric effect for example ULH devices and liquid crystal media that are especially suitable for flexoelectric devices and are known from EP 0971016, GB 2356629 and Coles, H.J., Musgrave, B., Coles, M.J. and Willmott, J., J. Mater. Chem., 11, p.2709-2716 (2001).
  • the Uniform Lying Helix (ULH) has high potential as a fast switching liquid crystal display mode. It is capable of sub millisecond switching at 35oC and possesses an intrinsically high aperture ratio, resulting in an energy efficient display mode.
  • the materials commonly used in media suitable for the ULH mode are typically bimesogens.
  • the corresponding LC media should exhibit favourable low ⁇ 1 values while preferably at the same time exhibiting:
  • liquid crystal means a compound that under suitable conditions of temperature, pressure and concentration can exist as a mesophase (nematic, smectic, etc.) or in particular as a LC phase.
  • Non-amphiphilic mesogenic compounds comprise for example one or more calamitic, banana-shaped or discotic mesogenic groups.
  • the term “mesogenic group” means in this context, a group with the ability to induce liquid crystal (LC) phase behaviour.
  • the compounds comprising mesogenic groups do not necessarily have to exhibit an LC phase themselves. It is also possible that they show LC phase behaviour only in mixtures with other compounds.
  • the term “liquid crystal” is used hereinafter for both mesogenic and LC materials.
  • aryl and heteroaryl groups encompass groups, which can be
  • monocyclic or polycyclic i.e. they can have one ring (such as, for example, phenyl) or two or more rings, which may also be fused (such as, for example, naphthyl) or covalently linked (such as, for example, biphenyl) or contain a combination of fused and linked rings.
  • Heteroaryl groups contain one or more heteroatoms, preferably selected from O, N, S and Se. Particular preference is given to mono-, bi- or tricyclic aryl groups having 6 to 25 C atoms and mono-, bi- or tricyclic heteroaryl groups having 2 to 25 C atoms, which optionally contain fused rings and which are optionally substituted.
  • aryl and heteroaryl groups Preference is furthermore given to 5 , 6 or 7-membered aryl and heteroaryl groups, in which, in addition, one or more CH groups may be replaced by N, S or O in such a way that O atoms and/or S atoms are not linked directly to one another.
  • Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl,
  • phenanthrene pyrene, dihydropyrene, chrysene, perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene,
  • spirobifluorene more preferably 1,4- phenylene, 4,4’-biphenylene, 1, 4- tephenylene.
  • Preferred heteroaryl groups are, for example, 5 membered rings, such as pyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, furan, thiophene, selenophene, oxazole, isoxazole, 1,2 thiazole, 1,3-thiazole, 1,2,3-oxadiazole, 1,2,4 oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 6 membered rings, such as pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine
  • heteroaryl groups may also be substituted by alkyl, alkoxy, thioalkyl, fluorine, fluoroalkyl or further aryl or heteroaryl groups.
  • the term“(non-aromatic) alicyclic and heterocyclic groups” encompass both saturated rings, i.e. those that contain exclusively single bonds and partially unsaturated rings, i.e.
  • Heterocyclic rings contain one or more heteroatoms, preferably selected from Si, O, N, S and Se.
  • the (non-aromatic) alicyclic and heterocyclic groups can be monocyclic, i.e. contain only one ring (such as, for example, cyclohexane) or polycyclic, i.e. contain a plurality of rings (such as, for example, decahydro-naphthalene or bicyclooctane). Particular preference is given to saturated groups. Preference is furthermore given to mono-, bi- or tricyclic groups having 3 to 25 C atoms, which optionally contain fused rings and that are optionally substituted.
  • Preferred alicyclic and heterocyclic groups are, for example, 5-membered groups, such as cyclopentane,
  • tetrahydrofuran tetrahydrothiofuran
  • pyrrolidine 6-membered groups, such as cyclohexane, silinane, cyclohexene, tetrahydropyran,
  • aryl-, heteroaryl-, alicyclic- and heterocyclic groups are 1,4-phenylene, 4,4’-biphenylene, 1, 4-terphenylene, 1,4-cyclohexylene, 4,4’- bicyclohexylene and 3,17- hexadecahydro-cyclopenta[a]-phenanthrene, optionally being substituted by one or more identical or different groups L.
  • Preferred substituents of the above-mentioned aryl-, heteroaryl-, alicyclic- and heterocyclic groups (L) are, for example, solubility-promoting groups, such as alkyl or alkoxy and electron-withdrawing groups, such as fluorine, nitro or nitrile.
  • substituents are, for example, halogen, CN, NO 2 , CH 3 , C 2 H 5 , OCH 3 , OC 2 H 5 , COCH 3 , COC 2 H 5 , COOCH 3 , COOC 2 H 5 , CF 3 , OCF 3 , OCHF 2 or OC 2 F 5 .
  • halogen denotes F, Cl, Br or I.
  • alkyl also encompass polyvalent groups, for example alkylene, arylene,
  • heteroarylene etc.
  • aryl denotes an aromatic carbon group or a group derived there from.
  • heteroaryl denotes "aryl” in accordance with the above definition containing one or more heteroatoms.
  • Preferred alkyl groups are, for example, methyl, ethyl, n propyl, isopropyl, n butyl, isobutyl, s butyl, t butyl, 2 methylbutyl, n pentyl, s pentyl, cyclo- pentyl, n hexyl, cyclohexyl, 2 ethylhexyl, n heptyl, cycloheptyl, n octyl, cyclooctyl, n nonyl, n decyl, n undecyl, n dodecyl, dodecanyl, trifluoro- methyl, perfluoro-n
  • Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxy- ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, 2- methylbutoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy, n-nonoxy, n- decoxy, n-undecoxy, n-dodecoxy.
  • Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl.
  • Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl. Oxaalkyl, i.e.
  • Preferred amino groups are, for example, dimethylamino, methylamino, methylphenylamino, phenylamino.
  • the term“chiral” in general is used to describe an object that is non- superimposable on its mirror image. “Achiral” (non- chiral) objects are objects that are identical to their mirror image. The terms“chiral nematic” and“cholesteric” are used synonymously in this application, unless explicitly stated otherwise.
  • the term“bimesogenic compound” relates to compounds comprising two mesogenic groups in the molecule. Just like normal mesogens, they can form many mesophases, depending on their structure.
  • bimesogenic compound may induce a second nematic phase, when added to a nematic liquid crystal medium.
  • Bimesogenic compounds are also known as“dimeric liquid crystals”.
  • the term "director” is known in prior art and means the preferred orientation direction of the long molecular axes (in case of calamitic compounds) or short molecular axes (in case of discotic compounds) of the liquid-crystalline molecules. In case of uniaxial ordering of such anisotropic molecules, the director is the axis of anisotropy.
  • the term“alignment” or“orientation” relates to alignment (orientation ordering) of anisotropic units of material such as small molecules or fragments of big molecules in a common direction named“alignment direction”.
  • the liquid- crystalline director coincides with the alignment direction so that the alignment direction corresponds to the direction of the anisotropy axis of the material.
  • plane orientation/alignment for example in a layer of an liquid-crystalline material, means that the long molecular axes (in case of calamitic compounds) or the short molecular axes (in case of discotic compounds) of a proportion of the liquid-crystalline molecules are oriented substantially parallel (about 180°) to the plane of the layer.
  • the term "homeotropic orientation/alignment”, for example in a layer of a liquid-crystalline material, means that the long molecular axes (in case of calamitic compounds) or the short molecular axes (in case of discotic compounds) of a proportion of the liquid-crystalline molecules are oriented at an angle ⁇ ("tilt angle") between about 80° to 90° relative to the plane of the layer.
  • the terms "uniform orientation” or “uniform alignment” of an liquid- crystalline material, for example in a layer of the material mean that the long molecular axes (in case of calamitic compounds) or the short molecular axes (in case of discotic compounds) of the liquid-crystalline molecules are oriented substantially in the same direction. In other words, the lines of liquid-crystalline director are parallel.
  • the wavelength of light generally referred to in this application is 550 nm, unless explicitly specified otherwise.
  • the birefringence ⁇ n herein is defined by the following equation
  • n e is the extraordinary refractive index and n o is the ordinary refractive index and the effective average refractive index n av. is given by the following equation
  • the extraordinary refractive index n e and the ordinary refractive index n o can be measured using an Abbe refractometer.
  • the term“dielectrically positive” is used for compounds or components with “dielectrically neutral” with -1.5 and“dielectrically negative” with 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. In case the solubility of the respective compound in the host medium is less than 10 % its concentration is reduced by a factor of 2 until the resultant medium is stable enough at least to allow the determination of its properties.
  • the concentration is kept at least at 5 %, however, in order to keep the significance of the results a high as possible.
  • the capacitance of the test mixtures are determined both in a cell with homeotropic and with homogeneous alignment.
  • the cell gap of both types of cells is approximately 20 ⁇ m.
  • the voltage applied is a
  • permittivity of the compounds is determined from the change of the respective values of a host medium upon addition of the compounds of interest.
  • the values are extrapolated to a concentration of the compounds of interest.
  • a typical host medium is ZLI-4792 or BL-087 both commercially available from Merck, Darmstadt.
  • ZLI-4792 or BL-087 both commercially available from Merck, Darmstadt.
  • the invention relates to a compound of formula I, R 11 -MG 11 -X 11 -Sp 11 -X 12 -MG 12 -R 12 I wherein R 11 and R 22 are each independently H, F, Cl, CN, NCS or a straight- chain or branched alkyl group, which may be
  • F, Cl, CN a straight-chain or branched alkyl, alkenyl or alkoxy group which may be unsubstituted, mono- or polysubstituted by halogen or CN,
  • F, CN or OCF 3 , MG 11 and MG 12 are each independently a mesogenic group
  • each independently a mesogenic group which comprises one or more aryl-, heteroaryl-, alicyclic- and heterocyclic groups, which are optionally substituted by F, Cl, CN, OCH 3 , OCF 3 , preferably each independently a mesogenic group, which comprises two or more aryl-, heteroaryl-, alicyclic- and heterocyclic groups wherein two of these rings are optionally be linked by a linking group selected from -CO-O-, -O-CO-, -CH 2 -O-, -O-CH 2 -, -CF 2 O- and/or -OCF 2 -, Sp 11 is a spacer group comprising 1, 3 or 5 to 40 C atoms, wherein one or more non-adjacent and non-terminal CH 2 groups may also be replaced by -O-, -S-, -NH-, -N(CH 3 )-, -CO-, -O-CO-, -S-CO-, -S-
  • the unit -X 11 -Sp 11 -X 12 - denotes -CF 2 O-Sp 11 -CF 2 O-, -OCF 2 - Sp 11 -OCF 2 -, -OCF 2 -Sp 11 -CF 2 O-, -CF 2 O-Sp 11 -OCF 2 -, -CF 2 O-Sp 11 -, -OCF 2 - Sp 11 -, -Sp 11 -CF 2 O-, or -Sp 11 -OCF 2 -.
  • the compounds of formula I are preferably selected from compounds wherein the groups (R 11 -MG 11 -) and
  • R 12 -MG 12 - in formula I are identical to each other.
  • Further preferred compounds of formula I are compounds selected from the group of compounds of formulae Ia and/or Ib, R 11 -MG 11 -OCF 2 -Sp 11 -CF 2 O-MG 12 -R 12 Ia R 11 -MG 11 -Sp 11 -CF 2 O-MG 12 -R 12 Ib wherein R 11 , R 22 , MG 11 , MG 12 , Sp 11 , have one of the meanings as given above under formula I.
  • Further preferred compounds of formula I are compounds selected from the group of compounds of formulae Ia-1 and/or Ib-1 R 11 -MG 11 -OCF 2 -(CH 2 ) n -CF 2 O-MG 12 -R 12 Ia-1 R 11 -MG 11 -(CH 2 ) n -CF 2 O-MG 12 -R 12 Ib-1 wherein R 11 , R 22 , MG 11 , MG 12 have one of the meanings as given above under formula I and n denotes 1, 3 or an integer from 5 to 15, more preferably an integer from 3 to 11, most preferably an odd integer (i.e.3, 5, 7, 9 or 11). If R 11 or R 12 is an alkyl or alkoxy radical, this may be straight chain or branched.
  • It is preferably straight-chain, has 2, 3, 4, 5, 6, 7 or 8 carbon atoms and accordingly is preferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy or octoxy, furthermore methyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetradecoxy, for example.
  • R 11 or R 12 is an alkenyl group are, this may be straight-chain or branched, preferably straight-chain, with up to 15 C atoms and more preferably, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl and corresponding isomers.
  • one of R 11 or R 12 is preferably alkenyl or alkinyl, preferably alkenyl, with up to 15 C atoms and the other is preferably alkyl, alkenyl or alkinyl, most preferably alky or alkenyl with 2 to 15 C atoms or alkoxy with 1 to 15, preferably 2 to 15, C atoms.
  • compounds of formula I containing an achiral branched group R 11 and/or R 12 may occasionally be of importance, for example, due to a reduction in the tendency towards crystallisation. Branched groups of this type generally do not contain more than one chain branch.
  • R 11 and/or R 12 are selected from CN, NO 2 , halogen, OCH 3 , OCN, SCN, COR x , COOR x or a mono- oligo- or polyfluorinated alkyl or alkoxy group with 1 to 4 C atoms.
  • R x is optionally fluorinated alkyl with 1 to 4, preferably 1 to 3 C atoms.
  • Halogen is preferably F or Cl.
  • R 11 and R 12 in formula I are selected of H, alkenyl, F, Cl, CN, NO 2 , OCH 3 , COCH 3 , COC 2 H 5 , COOCH 3 , COOC 2 H 5 , CF 3 ,
  • the compounds of formula Ia-1 are selected from the following compounds: R 11 -Phe-OCF 2 -(CH 2 ) n -CF 2 O-Phe-R12
  • PheL is 1,4-phenylene, which is substituted by one, two or
  • the compounds of formula Ib-1 are selected from the following compounds: R 11 -Phe-(CH 2 ) n -CF 2 O-Phe-R 12 Ib-1- I R 11 -PheL-(CH 2 ) n -CF 2 O-Phe-R 12 Ib-1- II R 11 -Phe-(CH2)n-CF2O-PheL-R 12 Ib-1- III R 11 -PheL-(CH2)n-CF2O-PheL-R 12 Ib-1- IV R 11 -Phe-(CH 2 ) n -CF 2 O-Phe-Z-Phe-R 12 Ib-1- V R 11 -PheL-(CH2)n-CF2O-Phe-Z-Phe-R 12 Ib-1- VI R 11 -Phe-(CH2)n-CF2O-Phe-Z-PheL-R 12 Ib-1- VII R 11 -Phe-(CH 2 ) n -CF 2 O-Phe-R 12
  • R 11 , R 12 , Phe, PheL, Z and n have one of the meanings as given above.
  • Further preferred compounds of formula I are compounds in which MG 11 and MG 12 are independently from one another a group of
  • groups may be replaced by N, trans-1,4-cyclo- hexylene in which, in addition, one or two non- adjacent CH2 groups may be replaced by O and/or S, 1,4-cyclohexylene, naphthalene-2,6-diyl, decahydro- naphthalene-2,6-diyl, 1,2,3,4-tetrahydro-naphthalene- 2,6-diyl, it being possible for all these groups to be unsubstituted, mono-, di-, tri- or tetrasubstituted with F, Cl, CN or alkyl, alkoxy, alkylcarbonyl or
  • alkoxycarbonyl groups wherein one or more H atoms may be substituted by F or Cl, preferably each independently in each occurrence 1,4- phenylene, wherein in addition one or more CH groups may be replaced by N or trans-1,4-cyclo- hexylene in which, in addition, one or two non- adjacent CH 2 groups may be replaced by O and/or S, it being possible for both ring groups to be
  • alkoxycarbonyl groups wherein one or more H atoms may be substituted by F or Cl
  • k is 0, 1, 2, 3 or 4, preferably 1, 2 or 3 and, most
  • Phe in these groups is 1,4-phenylene
  • PheL is a 1,4-phenylene group which is substituted by 1 to 4 groups L, with L being preferably F, Cl, CN, OH, NO 2 or an optionally fluorinated alkyl, alkoxy or alkanoyl group with 1 to 7 C atoms, very preferably F, Cl, CN, OH, NO 2 , CH 3 , C 2 H 5 , OCH 3 , OC 2 H 5 , COCH 3 , COC 2 H 5 , COOCH 3 , COOC 2 H 5 , CF 3 , OCF 3 , OCHF 2 , OC 2 F 5 , in particular F, Cl, CN, CH 3 , C 2 H 5 , OCH 3 , COCH 3 and OCF 3 , most preferably F, Cl, CH 3 , OCH 3 and COCH 3 and
  • PheL is 1,4-phenylene, which is substituted by one, two or three fluorine atoms, by one or two Cl atoms or by one Cl atom and one F atom and
  • the compounds of formula Ia-1 are selected from the following compounds: R 11 -Phe-Z-Phe-OCF 2 -(CH 2 ) n -CF 2 O-Phe-Z-Phe-R12
  • R 11 , R 12 , Phe, PheL, Z and n have one of the meanings as given above.
  • the compounds of formula Ib-1 are selected from the following compounds: R 11 -Phe-Z-Phe-(CH 2 ) n -CF 2 O-Phe-Z-Phe-R 12 Ib-1- 1 R 11 -Phe-Z-PheL-OCF2-(CH2)n-Phe-Z-Phe-R 12 Ib-1- 2 R 11 -PheL-Z-Phe-OCF2-(CH2)n-Phe-Z-Phe-R 12 Ib-1- 3 R 11 -Phe-Z-PheL-(CH 2 ) n -CF 2 O-Phe-Z-Phe-R 12 Ib-1- 4 R 11 -PheL-Z-Phe-(CH2)n-CF2O-Phe-Z-Phe-R 12 Ib-1- 5 R 11 -PheL-
  • R 11 , R 12 , Phe and PheL have one of the meanings as given above and n denotes 5, 7, 9 or 11.
  • Further preferred compounds of formula Ib-1 are selected from the following compounds: R 11 -Phe-Phe-(CH2)n-CF2O-Phe-Phe-R 12 Ib-1- 1 a R 11 -Phe-PheL-OCF 2 -(CH 2 ) n -Phe-Phe-R 12 Ib-1- 2 a R 11 -PheL-Phe-OCF2-(CH2)n-Phe-Phe-R 12 Ib-1- 3 a R 11 -Phe-PheL-(CH 2 ) n -CF 2 O-Phe-Phe-R 12 Ib-1- 4 a R 11 -PheL-Phe-(CH 2 ) n -CF 2 O-Phe-Phe-R 12 Ib-1- 5 a R 11 -PheL-P
  • L is preferably F, Cl, CH 3 , OCH 3 and COCH 3 .
  • R 11 , R 12 have one of the meanings as given above, preferably both R 11 and R 12 are identical and denote both CN or F, likewise preferably R 11 and R 12 are different and at least one of them denote CN or F and n preferably denotes 7 or 9.
  • Further preferred compounds are of formula Ib-1, for example, are preferably selected from the following compounds:
  • R 11 , R 12 have one of the meanings as given above, preferably both R 11 and R 12 are identical and denote both CN or F, likewise preferably R 11 and R 12 are different and at least one of them denote CN or F and n preferably denotes 7 or 9.
  • the compounds of formula I can be synthesized according to or in analogy to methods which are known per se and which are described in standard works of organic chemistry such as, for example, Houben-Weyl, Methoden der organischen Chemie, Thieme-Verlag, Stuttgart.
  • the compounds of formula Ia-1 can be s nthesized accordin to or in analo to the followin s nthesis scheme:
  • the invention relates also to a method of production of compounds of formula Ia-1 com risin at least the step of reacting a compound of
  • the compounds of formula Ib-1 can be synthesized according to or in analogy to the following synthesis scheme:
  • the compounds of formula I and its subformulae can be beneficially utilized in LC media to improve the properties of such media, in particular in LC media for flexoelectric applications.
  • one of the main advantages of using compounds of formula I in LC media for flexoelectric applications is improving the switching speed in the ULH (uniform lying helix) geometry, particularly at
  • the invention also relates to the use of compounds of formula I in LC media and to a LC media comprising one or more compounds of formula I, as such.
  • the LC media in accordance with the present invention comprise one or more compounds of formula II, R 21 -A 21 -A 22 -(CH2)a-A 23 -A 24 -R 22 II wherein
  • R 21 and R 22 denote independently H, F, Cl, CN, NCS or a straight- chain or branched alkyl group, which may be
  • F, Cl, CN a straight-chain or branched alkyl or alkoxy group which may be unsubstituted, mono- or polysubstituted by halogen or CN,
  • a 21 to A 24 denote independently in each occurrence a aryl-,
  • 1,4-phenylene wherein in addition one or more CH groups may be replaced by N, trans-1,4- cyclo-hexylene in which, in addition, one or two non- adjacent CH 2 groups may be replaced by O and/or S, 1,4-cyclohexenylene, 1,4-bicyclo-(2,2,2)-octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydro- naphthalene-2,6-diyl, 1,2,3,4-tetrahydro-naphthalene- 2,6-diyl, cyclobutane-1,3-diyl, spiro[3.3]heptane-2,6- diyl or dispiro[3.1.3.1] decane-2,8-diyl, it being possible for all these groups to be unsubstituted, mono-, di-, tri- or tetrasubstituted with F, Cl,
  • Preferred compounds of formula II are selected from compounds in which the groups (-A 21 -A 22 -) and (-A 23 -A 24 -) are each and independently selected from the following groups
  • Phe in these groups is 1,4-phenylene
  • PheL is a 1,4-phenylene group which is substituted by 1 to 4 groups L, with L being preferably F, Cl, CN, OH, NO 2 or an optionally fluorinated alkyl, alkoxy or alkanoyl group with 1 to 7 C atoms, very preferably F, Cl, CN, OH, NO 2 , CH 3 , C 2 H 5 , OCH 3 , OC 2 H 5 , COCH 3 , COC 2 H 5 , COOCH 3 ,
  • Cyc is 1,4-cyclohexylene.
  • compounds of formula II wherein the groups (R 21 -A 21 -A 22 -) and (-A 23 -A 24 -R 22 ) in formula II are identical or mirror images.
  • compounds of formula II wherein (R 21 -A 21 -A 22 -) and (-A 23 -A 24 -R 22 ) in formula II are different.
  • Preferred compounds of formula II are indicated below:
  • n denotes an integer from 1 to 15, preferably an odd (i.e.
  • the compounds of formula II can be synthesized according to or in analogy to methods which are known per se and which are described in standard works of organic chemistry such as, for example, Houben-Weyl, Methoden der organischen Chemie, Thieme-Verlag, Stuttgart. A preferred method of preparation can be taken from WO 2013/004333 A1.
  • the utilization of compounds of formula II beside compounds of formula I is especially useful in order to further improve the switching speeds whilst maintaining a good phase range and a favorable value for e/K.
  • the LC media in accordance with the present invention comprise one or more compounds of formula III, R 31 -A 31 -A 32 -(A 33 ) b -Z 31 -(CH 2 ) c -Z 32 -A 34 -A 35 -A 36 -R 32 III wherein
  • R 31 and R 32 have each and independently from another one of the meanings as given for R 21 and R 22 under formula II, A 31 to A 36 have each and independently from another one of the meanings as given for A 21 to A 24 under formula II, Z 31 and Z 32 are each independently in each occurrence,
  • -CH CH-COO-
  • b denotes an integer from 1 to 15, preferably an odd (i.e.
  • Preferred compounds of formula III are selected from compounds in which c denotes 0 and the group (-A 31 -A 32 -) is selected from the groups MG-1 to MG-8 as given above. Further preferred compounds of formula III are selected from compounds in which c denotes 1 and the groups (-A 24 -A 25 -A 26 -) and (-A 21 -A 22 -A 23 -) are each and independently selected from the following groups -Cyc-Cyc-Cyc- MG-9
  • the compounds of formula III can be synthesized according to or in analogy to methods which are known per se and which are described in standard works of organic chemistry such as, for example, Houben-Weyl, Methoden der organischen Chemie, Thieme-Verlag, Stuttgart.
  • the utilization of compounds of formula III beside compounds of formula I is especially useful in order to achieve high stabilities, favourable high clearing points and broad phase ranges, as well as, low appearances of the nematic twist-bend phase.
  • the LC medium in accordance with the present invention comprises one or more compounds of formula IV, R 41 -A 41 -A 42 -Z 41 -(CH 2 ) d -Z 42 -A 43 -A 44 -R 42 IV wherein
  • R 41 and R 42 have each and independently one of the meanings as given above for R 21 under formula II
  • a 41 to A 44 have each and independently one of the meanings as given above for A 21 under formula II
  • Z 41 and Z 42 are each independently in each occurrence
  • -CH CH-COO-
  • d denotes an integer from 1 to 15, preferably an odd (i.e.
  • Preferred compounds of formula IV are selected from compounds in which the groups (-A 41 -A 42 -) and (-A 43 -A 44 -) are each and independently selected from the groups of MG-1 to MG-8 as given above.
  • Especially preferred compounds of formula IV are selected from the group of compounds of the following formulae: - symmetrical ones (IVa and IVb):
  • the LC medium in accordance with the present invention additionally comprises one or more compounds of formula V, R 51 -A 51 -Z 51 -(CH 2 ) e -Z 52 -A 52 -(A 53 ) f -R 52 V wherein
  • R 51 and R 52 have each and independently one of the meanings as given above for R 21 under formula II
  • a 51 to A 53 have each and independently one of the meanings as given above for A 21 under formula II
  • Z 51 and Z 52 are each independently in each occurrence
  • -CH CH-COO-
  • e denotes an integer from 1 to 15, preferably an odd (i.e.
  • a 51 is selected from the following group of formulae Va’ to Vh’ and the mirror images of formulae Vb’, Ve’ and Vf’
  • R 51 and R 52 in formula V are selected of H, F, Cl, CN, NO2, OCH 3 , COCH 3 , COC2H5, COOCH 3 , COOC2H5, CF3, C2F5, OCF3, OCHF2 and OC 2 F 5 , in particular of H, F, Cl, CN, OCH 3 and OCF 3 , especially of H, F, CN and OCF 3.
  • Preferred compounds of formula V are selected from the group of compounds of formulae VA to VE, preferably of formulae VA and/or VD, most preferably of formula VD,
  • LG 51 is Z 51 -(CH2)z-Z 52 , (F) 0 denotes H and
  • (F) 1 denotes F. and the other parameters have the respective meanings given above including the preferred meanings.
  • Z 51 -(CH 2 ) z -Z 52 denotes -O-CO-(CH 2 ) n -CO-O-, -O-(CH 2 ) n -O- or -(CH 2 ) n -, more preferably -O-CO-(CH 2 ) n -CO-O-, wherein n denotes 3, 5, 7 or 9,
  • Particularly preferred compounds of formula VA are selected from the group of compounds of formulae VA-1 to VA-3
  • Particularly preferred compounds of formula VB are selected from the group of compounds of formulae VB-1 to VB-3
  • Particularly preferred compounds of formula VC are selected from the group of compounds of formulae VC-1 and VC-2
  • the LC medium in accordance with the present invention additionally comprises one or more compounds of formula VI, R 61 -A 61 -A 62 -(CH2)g-Z 61 -A 63 -A 64 -(A 65 )h-R 62 VI wherein R 61 and R 62 have each and independently one of the meanings as given above for R 21 under formula II, A 61 to A 64 have each and independently one of the meanings as given above for A 21 under formula II, Z 61 denotes -O-, -COO-, -OCO-, -O-CO-O-, -OCH 2 -, -CH 2 O,
  • h denotes 0 or 1
  • g denotes an integer from 1 to 15, preferably an odd (i.e.
  • Preferred compounds of formula VI are selected from compounds in which the groups (-A 61 -A 62 -) and (-A 63 -A 64 -) are each and independently selected from the groups of MG-1 to MG-8 as given above. Further preferred are compounds of formula VI wherein h denotes 0 and the groups (-A 61 -A 62 -) and (-A 63 -A 64 -(A 65 ) h ) in formula VI are not identical or not mirror images or wherein h denotes 1 In particular preferred compounds of formula VI are selected from the group of compounds of the following formulae,
  • the compounds of formula VI can be synthesized according to or in analogy to methods which are known per se and which are described in standard works of organic chemistry such as, for example, Houben-Weyl, Methoden der organischen Chemie, Thieme-Verlag, Stuttgart.
  • the compounds of formula VI are synthesized according to or in analogy to methods which are disclosed for example in WO 2014/005672 A1.
  • the utilization of compounds of formula VI beside compounds of formula I is especially useful in order to achieve high clearing points and also favorable values for e/K.
  • the LC medium in accordance with the present invention additionally comprises one, two, three or more compounds of formula VII, R 71 -A 71 -Z 71 -A 72 -(Z 72 -A 73 ) i -(CH 2 ) j -(A 74 -Z 73 -) k -A 75 -Z 74 -A 76 -R 72 VII wherein
  • R 71 and R 72 have each and independently one of the meanings as given above for R 21 under formula II
  • a 71 to A 76 have each and independently one of the meanings as given above for A 21 under formula II
  • Z 71 to Z 74 each and independently denotes -COO-, -OCO-,
  • j denotes an integer from 1 to 15, preferably an odd (i.e.
  • Preferred compounds of formula VII are selected from compounds in which at least one of the groups -A 71 -Z 71 -A 72 -(Z 72 -A 73 ) i -, -(A 74 -Z 73 -) k -A 75 -Z 74 -A 76 - are is selected from the groups of MGa to MGn (the two reference Nos.“MG i” and“MG l” being deliberately omitted to avoid any confusion) and their mirror images
  • L is in each occurrence independently of each other preferably F, Cl, CN or an optionally fluorinated alkyl, alkoxy or alkanoyl group with 1 to 7 C atoms, very preferably F, Cl, CN, CH 3 , C2H5, OCH 3 , OC2H5, COCH 3 , COC2H5, COOCH 3 , COOC2H5, CF3, OCF3, OCHF2, OC2F5, in particular F, Cl, CN, CH 3 , C2H5, OCH 3 , COCH 3 and OCF3, most
  • F, Cl, CH 3 , OCH 3 and COCH 3 and r is in each occurrence independently of each other 0, 1, 2, 3 or 4, preferably 0, 1 or 2.
  • R 71 and R 72 each and independently denote F or CN.
  • the compounds of formula VII can be synthesized according to or in analogy to methods which are known per se and which are described in standard works of organic chemistry such as, for example, Houben-Weyl, Methoden der organischen Chemie, Thieme-Verlag, Stuttgart.
  • the compounds of formula VII are synthesized according to or in analogy to methods which are disclosed for example in WO 2013/174478 A1.
  • the medium in accordance with the present invention optionally comprises one or more chiral dopants, especially when utilized in a flexoelectric device.
  • the chiral compounds induce a chiral nematic texture with a pitch (P 0 ), which is in a first approximation inversely proportional to the
  • HTP helical twisting power
  • c concentration of the chiral compound.
  • a uniform lying helix texture is realized using a chiral nematic liquid crystal with a short pitch, typically in the range from 0.2 ⁇ m to 1 ⁇ m, preferably of 1.0 ⁇ m or less, in particular of 0.5 ⁇ m or less, which is unidirectional aligned with its helical axis parallel to the substrates, e. g. glass plates, of a liquid crystal cell.
  • the helical axis of the chiral nematic liquid crystal is equivalent to the optical axis of a birefringent plate.
  • Preferred are chiral dopants with a high helical twisting power (HTP), in particular those disclosed in WO 98/00428.
  • used chiral dopants are e.g. the commercially available
  • the chiral dopants are preferably selected from formula VIII,
  • the above-mentioned chiral dopants R/S-5011 and the compounds of formula VIII and IX exhibit a very high helical twisting power (HTP) and are therefore particularly useful for the purpose of the present invention.
  • the liquid crystalline medium preferably comprises preferably 1 to 5, in particular 1 to 3, very preferably 1 or 2 chiral dopants, preferably selected from the above formula VIII, and/or formula IX and/or R-5011 or S-5011, very preferably, the chiral compound is R-5011, S- 5011.
  • the amount of chiral compounds in the liquid crystalline medium is preferably from 0.1 to 15 %, in particular from 0.5 to 10 %, very preferably 1 to 5 % by weight of the total mixture.
  • the LC medium comprises one or more nematic LC compounds selected from compounds indicated below:
  • liquid crystal media may contain further additives like for example stabilizers, inhibitors, surface-active compounds, lubricating agents, wetting agents, dispersing agents, hydrophobing agents, adhesive agents, flow improvers, defoaming agents, deaerators, diluents, reactive diluents, auxiliaries, colourants, dyes, pigments or nanoparticles in usual concentrations.
  • further additives like for example stabilizers, inhibitors, surface-active compounds, lubricating agents, wetting agents, dispersing agents, hydrophobing agents, adhesive agents, flow improvers, defoaming agents, deaerators, diluents, reactive diluents, auxiliaries, colourants, dyes, pigments or nanoparticles in usual concentrations.
  • the total concentration of these further constituents is in the range of 0.1 % to 10 %, preferably 0.1 % to 6 %, based on the total mixture.
  • the concentrations of the individual compounds used each are preferably in the range of 0.1 % to 3 %.
  • the concentration of these and of similar additives is not taken into consideration for the values and ranges of the concentrations of the liquid crystal components and compounds of the liquid crystal media in this application. This also holds for the concentration of the dichroic dyes used in the mixtures, which are not counted when the concentrations of the compounds respectively the components of the host medium are specified.
  • the concentration of the respective additives is always given relative to the final doped mixture. In general, the total concentration of all compounds in the media according to this application is 100 %.
  • the liquid crystal media according to the present invention consists of several compounds, preferably of 2 to 40, more preferably of 3 to 30 and most preferably of 4 to 25 compounds.
  • the media in accordance with the present invention exhibit high values of the elastic constant k 11 and a high flexoelectric coefficient e.
  • the liquid crystal media preferably exhibit a k 11 ⁇ 100 pN, preferably ⁇ 20 pN.
  • the liquid crystal media preferably exhibit a k 33 ⁇ 100 pN, preferably ⁇ 15 pN.
  • the liquid crystal media preferably exhibit a flexoelectric coefficient ⁇ e 11 ⁇ 0.2 pC/m, preferably ⁇ 1 pC/m.
  • the liquid crystal media preferably exhibit a flexoelectric coefficient ⁇ e 33 ⁇ 0.2 pC/m, preferably ⁇ 2 pC/m.
  • the liquid crystal media preferably exhibit a flexo-elastic ratio ( ⁇ / K) in the range from 1 to 10 V -1 , preferably in the range from 1 to 7 V -1 , more preferably in the range from 1 to 5 V -1 .
  • the media in accordance with the present invention exhibit high clearing points up to 60°C and higher, preferably up 65°C and higher and more preferably up to 70°C and higher.
  • the media in accordance with the present invention exhibit broad nematic phases of 30°C and more, preferably 35°C and more or even 40°C or more.
  • the media in accordance with the present invention exhibit N TB phases below 20°C or less, preferably below 15°C or less and more preferably below 0°C or less.
  • the media in accordance with the present invention exhibit high stabilities against crystallization at room temperature of more than 100 h, preferably more than 250 h or more than 1000 h.
  • the media in accordance with the present invention exhibit high stabilities against crystallization even at low temperatures (LTS).
  • the media do not crystallize even at temperatures down to 0°C, preferably down to -10°C, more preferably down to -20°C.
  • the LC medium comprises: ⁇ 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds of formula I, preferably selected from formulae Ia-1-2a, Ia-1-5a, Ib-1-4a and/or Ib-1-9a. The amount of
  • compounds of formula I in the liquid crystalline medium as a whole is preferably in the range from 5 to 50 %, in particular in the range from 6 to 30 %, especially in the range from 7 to 20 % by weight of the total mixture, and ⁇ optionally 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds of formula II, preferably selected from compounds compounds of formula II wherein (-A 21 -A 22 -) and (-A 23 -A 24 -) in formula II are identical or mirror images, more preferably of compounds of formulae II’a-5 and/or II’a-6.
  • the amount of compounds of formula II in the liquid crystalline medium is preferably in the range from 0 to 30 %, more preferably in the range from 1 to 20 %, even more preferably in the range from 2 to 10 % by weight of the total mixture, and/or ⁇ optionally 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds of formula III, preferably selected from symmetrical compounds of the above formulae IIIc-2 and/or IIIc-3.
  • the amount of compounds of formula III in the liquid crystalline medium, if present, is preferably in the range from 1 to 50 %, more preferably in the range from 5 to 30 %, even more preferably in the range from 10 to 20 % by weight of the total mixture, and/or
  • ⁇ optionally, 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds of formula IV, preferably selected from the symmetrical ones IVb and/or non-symmetrical ones IVc, more preferably from formulae IVb-5, IVc-2, IVc-3, IVc-12 and or IVc-15.
  • the amount of compounds of formula IV in the liquid crystalline medium, if present, is preferably in the range from 1 to 98 %, more preferably in the range from 20 to 80 %, even more preferably in the range from 30 to 60 % by weight of the total mixture, and/or ⁇ optionally, 1 to 6, in particular 2 to 5, very preferably 3 or 4
  • compounds of formula V preferably selected from the above formulae VA-1, VD-2 and/or VD-3.
  • the amount of compounds of formula V in the liquid crystalline medium is preferably in the range from 1 to 70 %, more preferably in the range from 10 to 60 %, even more preferably in the range from 20 to 50 % by weight of the total mixture, and/or ⁇ optionally 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds from the above formulae VI, preferably form compounds of formula VI-4, VI-5, VI-7 and/or VI-9.
  • the amount of compounds of formula VI in the liquid crystalline medium is preferably from 1 to 40 %, in particular from 5 to 25 %, very preferably 10 to 15 % by weight of the total mixture, and/or ⁇ optionally 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds from the above formulae VII, preferably form compounds of formula VII-4, VII-5 and/or VII-8.
  • the amount of compounds of formula VII in the liquid crystalline medium, if present, is preferably from 1 to 35 %, in particular from 5 to 25 %, very preferably 10 to 15 % by weight of the total mixture,
  • the chiral compound is R-5011 or S-5011.
  • the amount of chiral compounds in the liquid crystalline medium is preferably from 1 to 15 %, in particular from 0.5 to 10 %, very preferably 0.1 to 5 % by weight of the total mixture, and/or ⁇ optionally up to 25, in particular up to 20, very preferably up to 15, different compounds selected from compounds of formula X.
  • the amount of compounds of formula X in the liquid crystalline medium as a whole is preferably from 1 to 50 %, in particular from 5 to 30 %, very preferably 10 to 25 % by weight of the total mixture, and/or ⁇ optionally further additives, such as for example stabilizers, antioxidants, etc. in usual concentrations.
  • the total concentration of these further constituents, if present, is in the range of 0.1 to 10 %, preferably 0.1 to 6 %, based on the total mixture.
  • the concentrations of the individual compounds used each are preferably in the range of 0.1 to 3 %.
  • the LC medium of the present invention consists only of compounds selected from formula I to X, very preferably the LC medium consists only of compounds selected from formula I to IX.
  • the compounds forming the LC medium in accordance with the present invention are mixed in conventional way. As a rule, the required amount of the compound used in the smaller amount is dissolved in the compound used in the greater amount. In case the temperature is above the clearing point of the compound used in the higher concentration, it is particularly easy to observe completion of the process of dissolution. It is, however, also possible to prepare the media by other conventional ways, e.g. using so-called pre-mixtures, which can be e.g.
  • the invention also relates to a process for the production of an LC medium as described above and below.
  • the invention relates to a process for the production of an LC medium comprising the steps of mixing one or more compounds of formula I, with at least one compound selected from compounds of formulae II to X.
  • liquid crystalline media in accordance with the present invention can be used in electro optic devices, for example liquid crystal devices, such as STN, TN, AMD-TN, temperature compensation, guest-host, phase change or surface stabilized or polymer stabilized cholesteric texture (SSCT, PSCT) displays, in active and passive optical elements like polarizers, compensators, reflectors, alignment layers, colour filters or holographic elements, in adhesives, synthetic resins with anisotropic mechanical properties, cosmetics, diagnostics, liquid crystal pigments, for decorative and security applications, in nonlinear optics, optical information storage or as chiral dopants.
  • a LC medium comprising at least one compound of formula I in electro optic devices.
  • a flexoelectric display according to a preferred embodiment of the present invention comprises two plane parallel substrates, preferably glass plates covered with a transparent conductive layer such as indium tin oxide (ITO) on their inner surfaces, optionally alignment layers and a medium comprising one or more compounds of formula I and a chiral dopant as described above and below.
  • ITO indium tin oxide
  • the optical axis is rotated in the plane of the cell, similar as the director of a ferroelectric liquid crystal rotate as in a surface stabilized ferroelectric liquid crystal display.
  • the field induces a splay bend structure in the director, which is accommodated by a tilt in the optical axis.
  • the angle of the rotation of the axis is in first approximation directly and linearly proportional to the strength of the electrical field. The optical effect is best seen when the liquid crystal cell is placed between crossed polarizers with the optical axis in the unpowered state at an angle of 22.5° to the absorption axis of one of the polarizers.
  • This angle of 22.5° is also the ideal angle of rotation of the electric field, as thus, by the inversion the electrical field, the optical axis is rotated by 45° and by appropriate selection of the relative orientations of the preferred direction of the axis of the helix, the absorption axis of the polarizer and the direction of the electric field, the optical axis can be switched from parallel to one polarizer to the centre angle between both polarizers. The optimum contrast is then achieved when the total angle of the switching of the optical axis is 45°.
  • the arrangement can be used as a switchable quarter wave plate, provided the optical retardation, i. e. the product of the effective birefringence of the liquid crystal and the cell gap, is selected to be the quarter of the wavelength.
  • the wavelength referred to is 550 nm, the wavelength for which the sensitivity of the human eye is highest, unless explicitly stated otherwise.
  • the angle of rotation of the optical axis ( ⁇ ) is given in good
  • P 0 is the undisturbed pitch of the cholesteric liquid crystal
  • E is the electrical field strength
  • the flexoelectric effect is characterized by fast response times (T on+ T off at 35°C) typically ranging from 1 ms to 10 ms, preferably ⁇ 5ms and even more preferably ⁇ 3ms. It further features excellent grey scale capability.
  • T on+ T off at 35°C fast response times
  • E c critical field
  • inventive media in accordance with the present invention can be aligned in their cholesteric phase into different states of orientation by methods that are known to the expert, such as surface treatment or electric fields. For example, they can be aligned into the planar
  • mesogenic material in a display cell or on a substrate means that the mesogenic groups in the liquid crystal or mesogenic material are oriented substantially parallel to the plane of the cell or substrate, respectively.
  • the term“homeotropic alignment” or orientation of a liquid crystal or mesogenic material in a display cell or on a substrate means that the mesogenic groups in the liquid crystal or mesogenic material are oriented substantially perpendicular to the plane of the cell or substrate, respectively.
  • This state is also known as Grandjean state and the texture of the sample, which is observable e.g. in a polarization microscope, as Grandjean texture.
  • Planar alignment can be achieved e.g. by surface treatment of the cell walls, for example by rubbing and/or coating with an alignment layer such as polyimide.
  • a Grandjean state with a high quality of alignment and only few defects can further be achieved by heating the sample to the isotropic phase, subsequently cooling to the chiral nematic phase at a temperature close to the chiral nematic-isotropic phase transition and flow alignment by lightly pressing the cell.
  • the sample shows selective reflection of incident light, with the central wavelength of reflection depending on the helical pitch and the mean refractive index of the material.
  • the sample When an electric field is applied to the electrodes, for example with a frequency from 10 Hz to 1 kHz and an amplitude of up to 12 V rms / ⁇ m, the sample is being switched into a homeotropic state where the helix is unwound and the molecules are oriented parallel to the field, i.e. normal to the plane of the electrodes.
  • the sample In the homeotropic state, the sample is transmissive when viewed in normal daylight and appears black when being put between crossed polarizers.
  • the sample Upon reduction or removal of the electric field in the homeotropic state, the sample adopts a focal conic texture, where the molecules exhibit a helically twisted structure with the helical axis being oriented
  • a focal conic state can also be achieved by applying only a weak electric field to a sample in its planar state. In the focal conic state the sample is scattering when viewed in normal daylight and appears bright between crossed polarizers.
  • a sample of a medium in accordance with the present invention in different states of orientation exhibits different transmission of light.
  • the respective state of orientation, as well as its quality of alignment can be controlled by measuring the light transmission of the sample depending on the strength of the applied electric field. Thereby it is also possible to determine the electric field strength required to
  • the above-described focal conic state consists of many disordered
  • the LC media may also comprise compounds in which, for example, H, N, O, Cl, F have been replaced by the corresponding isotopes.
  • T N,I clearing point
  • K crystalline
  • N nematic
  • N TB second nematic
  • S or Sm smectic
  • Ch cholesteric
  • I isotropic
  • Tg glass transition.
  • the numbers between the symbols indicate the phase transition temperatures in°C.
  • n, m and l denote an integer between 1 and 12.
  • Table A lists the symbols used for the ring elements, table B those for the linking groups and table C those for the symbols for the left hand and the right hand end groups of the molecules.
  • 2-Trimethylsilyl-1,3-dithiane 3 (52.8 g, 269 mmol) is dissolved in 190 ml tetrahydrofuran and cooled to -70°C.
  • Butyllithium (107.5 ml of a 2.5 M solution in hexanes, 269 mmol) is slowly added. After the addition is complete, the mixture is warmed to room temperature for 2 hours and then cooled again to -70°C.20 g of dialdehyde 2 in 80 ml tetrahydrofuran is slowly added at that temperature. After the addition is complete, the mixture is warmed to room temperature and worked up as usual. The residue is distilled under reduced pressure and gave 22.9 g of product 4 with a boiling point of 67-74°C at a pressure of 0.1 mbar.
  • Bis(dithiane) 4 (15.4 mmol) is suspended in 200 ml dichloromethane and cooled to -30°C.
  • Trifluoromethane sulfonic acid (2.98 ml, 34 mmol) is added dropwise while stirring and the mixture is warmed to room temperature for 30 min. It is then cooled again to -70°C, the two phenols 5 (3.1 g, 15.4 mmol) and 6 (3.3 g, 15.4 mmol) together with triethylamine (7.7 ml, 56 mmol) and 70 ml dichloromethane are added dropwise to the mixture.
  • Triethylamine trishydrofluoride (24.9 ml, 154 mmol) is added and subsequently within a period of 60 min bromine (7.9 ml, 154 mmol) in 65 ml dichloromethane. After stirring for one hour at -70°C, the mixture is allowed to warm to -30°C and morpholine (13.5 ml, 154 mmol) is added below -20°C. After warming to 0°C, the mixture is poured onto 200 ml ice water and 19.7 ml aqueous KOH (47 %). The pH is adjusted to approximately 9.0 with additional small amounts of the KOH solution. The organic phase is separated and worked up as usual. After chromatography, of compound 7 (F-PGI-QI-9-Q-PP-N) is isolated.
  • Dithiane 4 (18.3 mmol) is suspended in 230 ml dichloromethane, cooled to -30°C and trifluoromethane sulfonic acid (3.5 ml, 40.3 mmol) is added dropwise. The mixture is allowed to warm to room temperature, stirred for 30 min and cooled again to -70°C. A mixture of 4-bromophenol 9 (7 g, 40.3 mmol) and triethylamine (9.1 ml, 65.9 mmol) dissolved in 100 ml dichloromethane is added. After the addition is complete, the mixture is stirred at -70°C for one hour.
  • Triethylamine trishydrofluoride (29.5 ml, 183 mmol) is added and after one hour bromine (9.4 ml, 183 mmol) in 50 ml dichloromethane. Stirring is continued for one hour and the mixture is warmed to -30°C. Morpholine (15.9 ml, 183 mmol) is added below -20°C. Workup is carried out as described above for compound 7 and gave compound 10. Step 2.2
  • 2-Trimethylsilyl-1,3-dithiane (6.7 ml, 35.4 mmol) is dissolved in 40 ml tetrahydrofuran and cooled to -70°C.
  • Butyllithium in hexanes (23.4 ml of a 15 % solution, 37.2 mmol) is added dropwise and the mixture is warmed to -20°C and stirred for 4 hours. It is then cooled again to -70°C and 19 (37.2 mmol) dissolved in 40 ml dichloromethane is added dropwise. After warming to room temperature followed by the usual workup, 20 is obtained as a yellow oil.
  • Triethylamine trishydrofluoride (13.9 ml, 86 mmol) is added dropwise and after 1 hour 4.4 ml (86 mmol) bromine in 100 ml dichloromethane. The mixture is stirred for 1 hour at -70°C. After warming to -20°C, morpholine (7.5 ml, 86 mmol) is added and stirring is continued for 1h at 0°C. After the usual workup 21 (N-PP-QI-5-GP-N) is obtained as a white powder.
  • C H 3 B Test cells and methods Typically a 3 ⁇ m thick cell, having an anti-parallel rubbed PI alignment layer, is filled on a hotplate at a temperature at which the flexoelectric mixture in the isotropic phase. After the cell has been filled, the phase transitions including clearing point and the crystallization behavior are determined using Differential Scanning Calorimetry (DSC) and verified by optical inspection. For optical phase transition measurements, a Mettler FP90 hot-stage controller connected to a FP82 hot-stage is used to control the temperature of the cell. The temperature is increased from ambient temperature at a rate of 5 degrees C per minute, until the onset of the isotropic phase is observed.
  • DSC Differential Scanning Calorimetry
  • the texture change is observed through crossed polarizers using an Olympus BX51 microscope and the respective temperature noted. Wires are then attached to the ITO electrodes of the cell using indium metal.
  • the cell is secured in a Linkam THMS600 hot-stage connected to a Linkam TMS93 hot-stage controller.
  • the hot-stage is secured to a rotation stage in an Olympus BX51 microscope.
  • the cell is heated until the liquid crystal is completely isotropic.
  • the cell is then cooled under an applied electric field until the sample is
  • the driving waveform is supplied by a Tektronix AFG3021B arbitrary function generator, which is sent through a
  • the applied field is monitored using a HP 34401A multimeter.
  • the tilt angle is measured using the aforementioned microscope and oscilloscope.
  • the undisturbed cholesteric pitch, P 0 is measured using an Ocean Optics USB4000 spectrometer attached to a computer.
  • the selective reflection band is obtained and the pitch determined from the spectral data.
  • the media shown in the following examples are well suitable for use in ULH-displays.
  • the material containing BM-4 in accordance with the present has a significant advantage with respect to the switching speed when compared to material comprising a compound of the prior art (CM*-2).
  • the TNI is also similar, something that is surprising when considering conventional liquid crystal materials with differing switching speeds when normally a strong inverse relationship between TNI and switching speeds is observed (i.e. higher TNI leads to reduced switching speeds).
  • the material containing BM-6 in accordance with the present has a significant advantage with respect to the switching speed when compared to material comprising a compound of the prior art (CM*-3).
  • the TNI is also similar, something that is surprising when considering conventional liquid crystal materials with differing switching speeds when normally a strong inverse relationship between TNI and switching speeds is observed (i.e. higher TNI leads to reduced switching speeds).

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Abstract

The invention relates to a compound of formula (I), R11-MG11-X11-Sp11-X12-MG12-R12 wherein R11, R22, MG11, MG12, Sp11, X11 and X12 have one of the meanings as given herein below. The invention further relates to method of production of a compound of formula I, to the use of said compounds in LC media and to LC media comprising one or more compounds of formula I. Further, the invention relates to a method of production of such LC media, to the use of such media in LC devices, in particular in flexoelectric LC devices and to a flexoelectric LC device comprising a LC medium according to the present invention. P16272 SL -118- Abstract The invention relates to a compound of formula (I), R 11 -MG 11 -X 11 -Sp 11 -X 12 -MG 12 -R 12 I wherein R 11, R 22, MG 11, MG 12, Sp 11, X 11 and X 12 have one of the meanings as given herein below. The invention further relates to method of production of a compound of formula (I), to the use of said compounds in LC media and to LC media comprising one or more compounds of formula (I). Further, the invention relates to a method of production of such LC media, to the use of such media in LC devices, in particular in flexoelectric LC devices and to a flexoelectric LC device comprising a LC medium according to the present invention.

Description

Liquid Crystal Medium and Liquid Crystal Device The invention relates to a compound of formula I, R11-MG11-X11-Sp11-X12-MG12-R12 I wherein R11, R22, MG11, MG12, Sp11, X11 and X12 have one of the meanings as given herein below. The invention further relates to method of production of a compound of formula I, to the use of said compounds in LC media and to LC media comprising one or more compounds of formula I. Further, the invention relates to a method of production of such LC media, to the use of such media in LC devices, in particular in flexoelectric LC devices and to a flexoelectric LC device comprising a LC medium according to the present invention. Background and Prior Art The flexoelectric effect is described, for example, by Chandrasekhar, "Liquid Crystals", 2nd edition, Cambridge University Press (1992) and P.G. deGennes et al., "The Physics of Liquid Crystals", 2nd edition, Oxford Science Publications (1995). Flexoelectric devices utilizing the flexoelectric effect, for example ULH devices and liquid crystal media that are especially suitable for flexoelectric devices and are known from EP 0971016, GB 2356629 and Coles, H.J., Musgrave, B., Coles, M.J. and Willmott, J., J. Mater. Chem., 11, p.2709-2716 (2001). The Uniform Lying Helix (ULH) has high potential as a fast switching liquid crystal display mode. It is capable of sub millisecond switching at 35ºC and possesses an intrinsically high aperture ratio, resulting in an energy efficient display mode. The materials commonly used in media suitable for the ULH mode are typically bimesogens. Due to the size of these materials and the presence of polar groups, such as, for example terminal cyano groups, they normally have high rotational viscosities (γ)1 in the order of many thousands mPa.s at 35ºC. The high values for γ1 are not problematically at increased temperatures of, for example, 35ºC, since the switching speed is directly proportional to γ.1 On the other hand, the values for ^1 are also proportional to the chiral pitch squared. Since the chiral pitch is normally in the region of 300nm this means that, the switching speeds are still very fast, in the region of 1 millisecond or a few milliseconds. However, upon reaching lower temperatures, such as room temperature at which the ULH devices are typically operated, the value for γ1 increases exponentially and even with a short pitch material the switching speeds increase beyond favourable levels. In order to maintain fast switching speeds at temperatures below 35ºC, the value γ1 of the LC mixtures needs to be reduced and therefore mixture components with lower γ1 need to be identified. Accordingly, there is a great demand for new bimesogenic compounds, which exhibit favourable low γ1 values while preferably at the same time exhibiting:
● favourable e/K (V-1) values,
● favourable broad nematic phase ranges and
● high clearing points. In addition to those requirements, the corresponding LC media should exhibit favourable low γ1 values while preferably at the same time exhibiting:
● low melting points,
● high clearing points,
● broad chiral nematic phase ranges,
● short temperature independent pitch lengths,
● high flexoelectric coefficients and
● a favourable low temperature stability without crystallization
effects in cells as well as in the bulk. Other aims of the present invention are immediately evident to the person skilled in the art from the following detailed description. Surprisingly, the inventors have found out that one or more of the above- mentioned aims can be achieved by providing a compound according to claim 1. Terms and Definitions
The term "liquid crystal", "mesomorphic compound” or "mesogenic compound" (also shortly referred to as "mesogen") means a compound that under suitable conditions of temperature, pressure and concentration can exist as a mesophase (nematic, smectic, etc.) or in particular as a LC phase. Non-amphiphilic mesogenic compounds comprise for example one or more calamitic, banana-shaped or discotic mesogenic groups. The term "mesogenic group" means in this context, a group with the ability to induce liquid crystal (LC) phase behaviour. The compounds comprising mesogenic groups do not necessarily have to exhibit an LC phase themselves. It is also possible that they show LC phase behaviour only in mixtures with other compounds. For the sake of simplicity, the term "liquid crystal" is used hereinafter for both mesogenic and LC materials. Throughout the application, unless stated explicitly otherwise, the term “aryl and heteroaryl groups” encompass groups, which can be
monocyclic or polycyclic, i.e. they can have one ring (such as, for example, phenyl) or two or more rings, which may also be fused (such as, for example, naphthyl) or covalently linked (such as, for example, biphenyl) or contain a combination of fused and linked rings. Heteroaryl groups contain one or more heteroatoms, preferably selected from O, N, S and Se. Particular preference is given to mono-, bi- or tricyclic aryl groups having 6 to 25 C atoms and mono-, bi- or tricyclic heteroaryl groups having 2 to 25 C atoms, which optionally contain fused rings and which are optionally substituted. Preference is furthermore given to 5 , 6 or 7-membered aryl and heteroaryl groups, in which, in addition, one or more CH groups may be replaced by N, S or O in such a way that O atoms and/or S atoms are not linked directly to one another. Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl,
[1,1':3',1'']terphenyl-2'-yl, naphthyl, anthracene, binaphthyl,
phenanthrene, pyrene, dihydropyrene, chrysene, perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene,
spirobifluorene, more preferably 1,4- phenylene, 4,4’-biphenylene, 1, 4- tephenylene. Preferred heteroaryl groups are, for example, 5 membered rings, such as pyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, furan, thiophene, selenophene, oxazole, isoxazole, 1,2 thiazole, 1,3-thiazole, 1,2,3-oxadiazole, 1,2,4 oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 6 membered rings, such as pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1,2,3,4- tetrazine, 1,2,3,5-tetrazine or condensed groups, such as indole, iso- indole, indolizine, indazole, benzimidazole, benzotriazole, purine, naphth- imidazole, phenanthrimidazole, pyridimidazole, pyrazinimidazole, quinoxalinimidazole, benzoxazole, naphthoxazole, anthroxazole, phen- anthroxazole, isoxazole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline, benzo-6,7-quino¬line, benzo-7,8-quinoline, benzoisoquinoline, acridine, phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine, quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarboline, phenanthridine, phenanthroline, thieno[2,3b]thiophene, thieno[3,2b]- thiophene, dithienothiophene, isobenzothiophene, dibenzothiophene, benzothiadiazothiophene or combinations of these groups. The heteroaryl groups may also be substituted by alkyl, alkoxy, thioalkyl, fluorine, fluoroalkyl or further aryl or heteroaryl groups. In the context of this application, the term“(non-aromatic) alicyclic and heterocyclic groups” encompass both saturated rings, i.e. those that contain exclusively single bonds and partially unsaturated rings, i.e.
those that may also contain multiple bonds. Heterocyclic rings contain one or more heteroatoms, preferably selected from Si, O, N, S and Se. The (non-aromatic) alicyclic and heterocyclic groups can be monocyclic, i.e. contain only one ring (such as, for example, cyclohexane) or polycyclic, i.e. contain a plurality of rings (such as, for example, decahydro-naphthalene or bicyclooctane). Particular preference is given to saturated groups. Preference is furthermore given to mono-, bi- or tricyclic groups having 3 to 25 C atoms, which optionally contain fused rings and that are optionally substituted. Preference is furthermore given to 5-, 6-, 7- or 8-membered carbocyclic groups in which, in addition, one or more C atoms may be replaced by Si and/or one or more CH groups may be replaced by N and/or one or more non-adjacent CH2 groups may be replaced by -O- and/or -S-. Preferred alicyclic and heterocyclic groups are, for example, 5-membered groups, such as cyclopentane,
tetrahydrofuran, tetrahydrothiofuran, pyrrolidine, 6-membered groups, such as cyclohexane, silinane, cyclohexene, tetrahydropyran,
tetrahydrothiopyran, 1,3-dioxane, 1,3-dithiane, piperidine, 7-membered groups, such as cycloheptane and fused groups, such as
tetrahydronaphthalene, decahydronaphthalene, indane,
bicyclo[1.1.1]¬pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl,
spiro[3.3]heptane-2,6-diyl, octahydro-4,7-methanoindane-2,5-diyl, more preferably 1,4-cyclohexylene 4,4’- bicyclohexylene, 3,17-hexadecahydro- cyclopenta[a]phenanthrene, optionally being substituted by one or more identical or different groups L. Especially preferred aryl-, heteroaryl-, alicyclic- and heterocyclic groups are 1,4-phenylene, 4,4’-biphenylene, 1, 4-terphenylene, 1,4-cyclohexylene, 4,4’- bicyclohexylene and 3,17- hexadecahydro-cyclopenta[a]-phenanthrene, optionally being substituted by one or more identical or different groups L. Preferred substituents of the above-mentioned aryl-, heteroaryl-, alicyclic- and heterocyclic groups (L) are, for example, solubility-promoting groups, such as alkyl or alkoxy and electron-withdrawing groups, such as fluorine, nitro or nitrile. Particularly preferred substituents are, for example, halogen, CN, NO2, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2 or OC2F5. Above and below "halogen" denotes F, Cl, Br or I. Above and below, the terms "alkyl", "aryl", "heteroaryl", etc., also encompass polyvalent groups, for example alkylene, arylene,
heteroarylene, etc. The term "aryl" denotes an aromatic carbon group or a group derived there from. The term "heteroaryl" denotes "aryl" in accordance with the above definition containing one or more heteroatoms. Preferred alkyl groups are, for example, methyl, ethyl, n propyl, isopropyl, n butyl, isobutyl, s butyl, t butyl, 2 methylbutyl, n pentyl, s pentyl, cyclo- pentyl, n hexyl, cyclohexyl, 2 ethylhexyl, n heptyl, cycloheptyl, n octyl, cyclooctyl, n nonyl, n decyl, n undecyl, n dodecyl, dodecanyl, trifluoro- methyl, perfluoro-n-butyl, 2,2,2-trifluoroethyl, perfluorooctyl, perfluoro- hexyl, etc. Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxy- ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, 2- methylbutoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy, n-nonoxy, n- decoxy, n-undecoxy, n-dodecoxy. Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl. Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl. Oxaalkyl, i.e. where one CH2 group is replaced by -O-, is preferably straight-chain 2-oxapropyl (= methoxymethyl), 2- (= ethoxymethyl) or 3-oxabutyl (= 2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5- oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl or 2-, 3-, 4-, 5-, 6-,7-, 8- or 9-oxadecyl, for example. Preferred amino groups are, for example, dimethylamino, methylamino, methylphenylamino, phenylamino. The term“chiral” in general is used to describe an object that is non- superimposable on its mirror image. “Achiral” (non- chiral) objects are objects that are identical to their mirror image. The terms“chiral nematic” and“cholesteric” are used synonymously in this application, unless explicitly stated otherwise. The term“bimesogenic compound” relates to compounds comprising two mesogenic groups in the molecule. Just like normal mesogens, they can form many mesophases, depending on their structure. In particular, bimesogenic compound may induce a second nematic phase, when added to a nematic liquid crystal medium. Bimesogenic compounds are also known as“dimeric liquid crystals”. The term "director" is known in prior art and means the preferred orientation direction of the long molecular axes (in case of calamitic compounds) or short molecular axes (in case of discotic compounds) of the liquid-crystalline molecules. In case of uniaxial ordering of such anisotropic molecules, the director is the axis of anisotropy. The term“alignment” or“orientation” relates to alignment (orientation ordering) of anisotropic units of material such as small molecules or fragments of big molecules in a common direction named“alignment direction”. In an aligned layer of liquid-crystalline material, the liquid- crystalline director coincides with the alignment direction so that the alignment direction corresponds to the direction of the anisotropy axis of the material. The term "planar orientation/alignment", for example in a layer of an liquid-crystalline material, means that the long molecular axes (in case of calamitic compounds) or the short molecular axes (in case of discotic compounds) of a proportion of the liquid-crystalline molecules are oriented substantially parallel (about 180°) to the plane of the layer. The term "homeotropic orientation/alignment", for example in a layer of a liquid-crystalline material, means that the long molecular axes (in case of calamitic compounds) or the short molecular axes (in case of discotic compounds) of a proportion of the liquid-crystalline molecules are oriented at an angle θ ("tilt angle") between about 80° to 90° relative to the plane of the layer. The terms "uniform orientation" or "uniform alignment" of an liquid- crystalline material, for example in a layer of the material, mean that the long molecular axes (in case of calamitic compounds) or the short molecular axes (in case of discotic compounds) of the liquid-crystalline molecules are oriented substantially in the same direction. In other words, the lines of liquid-crystalline director are parallel.
The wavelength of light generally referred to in this application is 550 nm, unless explicitly specified otherwise. The birefringence Δn herein is defined by the following equation
Figure imgf000009_0001
wherein ne is the extraordinary refractive index and no is the ordinary refractive index and the effective average refractive index nav. is given by the following equation
Figure imgf000009_0002
The extraordinary refractive index ne and the ordinary refractive index no can be measured using an Abbe refractometer. In the present application the term“dielectrically positive” is used for compounds or components with
Figure imgf000010_0005
“dielectrically neutral” with -1.5
Figure imgf000010_0003
and“dielectrically negative” with
Figure imgf000010_0004
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. In case the solubility of the respective compound in the host medium is less than 10 % its concentration is reduced by a factor of 2 until the resultant medium is stable enough at least to allow the determination of its properties. Preferably, the concentration is kept at least at 5 %, however, in order to keep the significance of the results a high as possible. The capacitance of the test mixtures are determined both in a cell with homeotropic and with homogeneous alignment. The cell gap of both types of cells is approximately 20 µm. The voltage applied is a
rectangular wave with a frequency of 1 kHz and a root mean square value typically of 0.5 V to 1.0 V; however, it is always selected to be below the capacitive threshold of the respective test mixture. is defined as whereas is The dielectric
Figure imgf000010_0006
Figure imgf000010_0008
Figure imgf000010_0007
permittivity of the compounds is determined from the change of the respective values of a host medium upon addition of the compounds of interest. The values are extrapolated to a concentration of the
compounds of interest of 100 %. A typical host medium is ZLI-4792 or BL-087 both commercially available from Merck, Darmstadt. For the present invention,
Figure imgf000010_0001
denote trans-1,4-cyclohexylene,
Figure imgf000010_0002
denote 1,4-phenylene. Furthermore, the definitions as given in C. Tschierske, G. Pelzl and S. Diele, Angew. Chem.2004, 116, 6340-6368 shall apply to non-defined terms related to liquid crystal materials in the instant application. Detailed description The invention relates to a compound of formula I, R11-MG11-X11-Sp11-X12-MG12-R12 I wherein R11 and R22 are each independently H, F, Cl, CN, NCS or a straight- chain or branched alkyl group, which may be
unsubstituted, mono- or polysubstituted by halogen or CN and in which one or more non-adjacent and non- terminal CH2 groups may be replaced, in each occurrence independently from one another, by -O-, -S-, -NH-, -N(CH3)-, -CO-, -COO-, -OCO-, -O-CO-O-, -S-CO-, -CO-S-, -CH=CH-, -CH=CF-, -CF=CF- or -C≡C- in such a manner that oxygen atoms are not linked directly to one another,
preferably F, Cl, CN, a straight-chain or branched alkyl, alkenyl or alkoxy group which may be unsubstituted, mono- or polysubstituted by halogen or CN,
more preferably F, CN or OCF3, MG11 and MG12 are each independently a mesogenic group,
preferably, each independently a mesogenic group, which comprises one or more aryl-, heteroaryl-, alicyclic- and heterocyclic groups, which are optionally substituted by F, Cl, CN, OCH3, OCF3, preferably each independently a mesogenic group, which comprises two or more aryl-, heteroaryl-, alicyclic- and heterocyclic groups wherein two of these rings are optionally be linked by a linking group selected from -CO-O-, -O-CO-, -CH2-O-, -O-CH2-, -CF2O- and/or -OCF2-, Sp11 is a spacer group comprising 1, 3 or 5 to 40 C atoms, wherein one or more non-adjacent and non-terminal CH2 groups may also be replaced by -O-, -S-, -NH-, -N(CH3)-, -CO-, -O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O-, -CF2-, -CF2O-, -OCF2- -C(OH)-, -CH(alkyl)-, -CH(alkenyl)-,-CH(alkoxyl)-, -CH(oxaalkyl)-, -CH=CH- or -C ^C-, however in such a way that no two O-atoms are adjacent to one another and no two groups selected from -O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O- and -CH=CH- are adjacent to each other, preferably–(CH2)n-, with n 1, 3 or an integer from 5 to 15, more preferably from 3 to 11, most preferably an odd integer (i.e.3, 5, 7, 9 or 11), X11 and X12 are -CF2-O-, -O-CF2- or a single bond, whereby at least one of X11 or X12 denotes -CF2-O-, or -O-CF2-. Preferably the unit -X11-Sp11-X12- denotes -CF2O-Sp11-CF2O-, -OCF2- Sp11-OCF2-, -OCF2-Sp11-CF2O-, -CF2O-Sp11-OCF2-, -CF2O-Sp11-, -OCF2- Sp11-, -Sp11-CF2O-, or -Sp11-OCF2-. Preferred are compounds of formula I wherein the mesogenic groups R11-MG11- and R12-MG12- are different from each other. In another embodiment, the compounds of formula I are preferably selected from compounds wherein the groups (R11-MG11-) and
(R12-MG12-) in formula I are identical to each other. Further preferred compounds of formula I are compounds selected from the group of compounds of formulae Ia and/or Ib, R11-MG11-OCF2-Sp11-CF2O-MG12-R12 Ia R11-MG11-Sp11-CF2O-MG12-R12 Ib wherein R11, R22, MG11, MG12, Sp11, have one of the meanings as given above under formula I. Further preferred compounds of formula I are compounds selected from the group of compounds of formulae Ia-1 and/or Ib-1 R11-MG11-OCF2-(CH2)n-CF2O-MG12-R12 Ia-1 R11-MG11-(CH2)n-CF2O-MG12-R12 Ib-1 wherein R11, R22, MG11, MG12 have one of the meanings as given above under formula I and n denotes 1, 3 or an integer from 5 to 15, more preferably an integer from 3 to 11, most preferably an odd integer (i.e.3, 5, 7, 9 or 11). If R11 or R12 is an alkyl or alkoxy radical, this may be straight chain or branched. It is preferably straight-chain, has 2, 3, 4, 5, 6, 7 or 8 carbon atoms and accordingly is preferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy or octoxy, furthermore methyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetradecoxy, for example. If R11 or R12 is an alkenyl group are, this may be straight-chain or branched, preferably straight-chain, with up to 15 C atoms and more preferably, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl and corresponding isomers. In case of compounds with two non-polar groups, one of R11 or R12 is preferably alkenyl or alkinyl, preferably alkenyl, with up to 15 C atoms and the other is preferably alkyl, alkenyl or alkinyl, most preferably alky or alkenyl with 2 to 15 C atoms or alkoxy with 1 to 15, preferably 2 to 15, C atoms. In addition, compounds of formula I containing an achiral branched group R11 and/or R12 may occasionally be of importance, for example, due to a reduction in the tendency towards crystallisation. Branched groups of this type generally do not contain more than one chain branch. Preferred achiral branched groups are isopropyl, isobutyl (=methylpropyl), isopentyl (=3-methylbutyl), isopropoxy, 2-methyl-propoxy and 3-methylbutoxy. In case of a compounds with a terminal polar group, R11 and/or R12 are selected from CN, NO2, halogen, OCH3, OCN, SCN, CORx, COORx or a mono- oligo- or polyfluorinated alkyl or alkoxy group with 1 to 4 C atoms.
Rx is optionally fluorinated alkyl with 1 to 4, preferably 1 to 3 C atoms.
Halogen is preferably F or Cl. Especially preferably R11 and R12 in formula I are selected of H, alkenyl, F, Cl, CN, NO2, OCH3, COCH3, COC2H5, COOCH3, COOC2H5, CF3,
C2F5, OCF3, OCHF2 and OC2F5, in particular of ethenyl, propenyl,
butenyl, F, Cl, CN, CF3, OCH3 and OCF3, especially of propenyl, butenyl, F, CN and OCF3. In a preferred embodiment the compounds of formula Ia-1 are selected from the following compounds: R11-Phe-OCF2-(CH2)n-CF2O-Phe-R12
Ia-1- I R11-PheL-OCF2-(CH2)n-CF2O-Phe-R12
Ia-1- II R11-PheL-OCF2-(CH2)n-CF2O-PheL-R12
Ia-1- III R11-Phe-OCF2-(CH2)n-CF2O-Phe-Z-Phe-R12
Ia-1- IV R11-PheL-OCF2-(CH2)n-CF2O-Phe-Z-Phe-R12
Ia-1- V R11-Phe-OCF2-(CH2)n-CF2O-PheL-Z-Phe-R12
Ia-1- VI R11-Phe-OCF2-(CH2)n-CF2O-Phe-Z-PheL-R12
Ia-1- VII R11-Phe-OCF2-(CH2)n-CF2O-PheL-Z-PheL-R12
Ia-1- VIII R11-PheL-OCF2-(CH2)n-CF2O-PheL-Z-Phe-R12
Ia-1- IX R11-PheL-OCF2-(CH2)n-CF2O-Phe-Z-PheL-R12
Ia-1- X R11-PheL-OCF2-(CH2)n-CF2O-PheL-Z-PheL-R12
Ia-1- XI wherein, R11, R12 have one of the meanings as given above and Phe is 1,4-phenylene,
PheL is 1,4-phenylene, which is substituted by one, two or
three fluorine atoms, by one or two Cl atoms or by one Cl atom and one F atom and
Z has one of the meanings of Z11 as given under partial formula II and if present twice, at least one is preferably selected from -C≡C-, -C=C-, -COO-, -OCO-, -O-CO-O-, -OCH2-, -CH2O-, -OCF2- or -CF2O-. In a preferred embodiment the compounds of formula Ib-1 are selected from the following compounds: R11-Phe-(CH2)n-CF2O-Phe-R12 Ib-1- I R11-PheL-(CH2)n-CF2O-Phe-R12 Ib-1- II R11-Phe-(CH2)n-CF2O-PheL-R12 Ib-1- III R11-PheL-(CH2)n-CF2O-PheL-R12 Ib-1- IV R11-Phe-(CH2)n-CF2O-Phe-Z-Phe-R12 Ib-1- V R11-PheL-(CH2)n-CF2O-Phe-Z-Phe-R12 Ib-1- VI R11-Phe-(CH2)n-CF2O-Phe-Z-PheL-R12 Ib-1- VII R11-Phe-(CH2)n-CF2O-PheL-Z-Phe-R12 Ib-1- VIII R11-Phe-(CH2)n-CF2O-PheL-Z-PheL-R12 Ib-1- IX R11-PheL-(CH2)n-CF2O-PheL-Z-Phe-R12 Ib-1- X R11-PheL-(CH2)n-CF2O-Phe-Z-PheL-R12 Ib-1- XI R11-PheL-(CH2)n-CF2O-PheL-Z-PheL-R12 Ib-1- XII R11-Phe-OCF2-(CH2)n-Phe-R12 Ib-1- XIII R11-PheL-OCF2-(CH2)n-Phe-R12 Ib-1- XIV R11-Phe-OCF2-(CH2)n-PheL-R12 Ib-1- XV R11-PheL-OCF2-(CH2)n-PheL-R12 Ib-1- XVI R11-Phe-OCF2-(CH2)n-Phe-Z-Phe-R12 Ib-1- XVII R11-PheL-OCF2-(CH2)n-Phe-Z-Phe-R12 Ib-1- XVIII R11-Phe-OCF2-(CH2)n-PheL-Z-Phe-R12 Ib-1- XIX R11-Phe-OCF2-(CH2)n-Phe-Z-PheL-R12
R11-Phe-OCF2-(CH2)n-PheL-Z-PheL-R12 Ib-1- XX R11-PheL-OCF2-(CH2)n-PheL-Z-Phe-R12 Ib-1- XXI R11-PheL-OCF2-(CH2)n-Phe-Z-PheL-R12 Ib-1- XXII R11-PheL-OCF2-(CH2)n-PheL-Z-PheL-R12 Ib-1- XXIII wherein, R11, R12, Phe, PheL, Z and n have one of the meanings as given above. Further preferred compounds of formula I are compounds in which MG11 and MG12 are independently from one another a group of
(partial) formula I* -A11-(Z11-A12)k- I* Wherein A11 and A12 each independently in each occurrence denote, 1,4- phenylene, wherein in addition one or more CH
groups may be replaced by N, trans-1,4-cyclo- hexylene in which, in addition, one or two non- adjacent CH2 groups may be replaced by O and/or S, 1,4-cyclohexylene, naphthalene-2,6-diyl, decahydro- naphthalene-2,6-diyl, 1,2,3,4-tetrahydro-naphthalene- 2,6-diyl, it being possible for all these groups to be unsubstituted, mono-, di-, tri- or tetrasubstituted with F, Cl, CN or alkyl, alkoxy, alkylcarbonyl or
alkoxycarbonyl groups, wherein one or more H atoms may be substituted by F or Cl, preferably each independently in each occurrence 1,4- phenylene, wherein in addition one or more CH groups may be replaced by N or trans-1,4-cyclo- hexylene in which, in addition, one or two non- adjacent CH2 groups may be replaced by O and/or S, it being possible for both ring groups to be
unsubstituted, mono-, di-, tri- or tetrasubstituted with F, Cl, CN or alkyl, alkoxy, alkylcarbonyl or
alkoxycarbonyl groups, wherein one or more H atoms may be substituted by F or Cl, Z11 are, independently of each other in each occurrence, a single bond, -COO-, -OCO-, -O-CO-O-, -OCH2-, -CH2O-, -OCF2-, -CF2O-, -CH2CH2-, -(CH2)4-, -CF2CF2-, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH- or -C ^C-, optionally substituted with one or more of F, S and/or Si,
preferably a single bond, k is 0, 1, 2, 3 or 4, preferably 1, 2 or 3 and, most
preferably 1 or 2. A smaller group of preferred mesogenic groups comprising only 6- membered rings is listed below. For reasons of simplicity, Phe in these groups is 1,4-phenylene, PheL is a 1,4-phenylene group which is substituted by 1 to 4 groups L, with L being preferably F, Cl, CN, OH, NO2 or an optionally fluorinated alkyl, alkoxy or alkanoyl group with 1 to 7 C atoms, very preferably F, Cl, CN, OH, NO2, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5, in particular F, Cl, CN, CH3, C2H5, OCH3, COCH3 and OCF3, most preferably F, Cl, CH3, OCH3 and COCH3 and Cyc is 1,4-cyclohexylene. This list comprises the subformulae shown below as well as their mirror images -Phe-Z-Phe- I*-1 -Phe-Z-Cyc- I*-2 -Cyc-Z-Cyc- I*-3 -Phe-Z-PheL- I*-4 -PheL-Z-Phe- I*-5 -PheL-Z-Cyc- I*-6 -PheL-Z-PheL- I*-7 -Phe-Z-Phe-Z-Phe- I*-8 -Phe-Z-Phe-Z-Cyc- I*-9 -Phe-Z-Cyc-Z-Phe- I*-10 -Cyc-Z-Phe-Z-Cyc- I*-11 -Phe-Z-Cyc-Z-Cyc- I*-12 -Cyc-Z-Cyc-Z-Cyc- I*-13 -Phe-Z-Phe-Z-PheL- I*-14 -Phe-Z-PheL-Z-Phe- I*-15 -PheL-Z-Phe-Z-Phe- I*-16 -PheL-Z-Phe-Z-PheL- I*-17 -PheL-Z-PheL-Z-Phe- I*-18 -PheL-Z-PheL-Z-PheL- I*-19 -Phe-Z-PheL-Z-Cyc- I*-20 -Phe-Z-Cyc-Z-PheL- I*-21 -Cyc-Z-Phe-Z-PheL- I*-22 -PheL-Z-Cyc-Z-PheL- I*-23 -PheL-Z-PheL-Z-Cyc- I*-24 -PheL-Z-Cyc-Z-Cyc- I*-25 -Cyc-Z-PheL-Z-Cyc- I*-26 wherein Cyc is 1,4-cyclohexlene, preferably trans-1,4-cyclohexlene, Phe is 1,4-phenylene,
PheL is 1,4-phenylene, which is substituted by one, two or three fluorine atoms, by one or two Cl atoms or by one Cl atom and one F atom and
Z has one of the meanings of Z11 as given under partial formula II and if present twice, at least one is preferably selected from -C≡C-, -C=C-, -COO-, -OCO-, -O-CO-O-, -OCH2-, -CH2O-, -OCF2- or -CF2O-. Particularly preferred are the sub-formulae I*-1, I*-4, I*-5, I*-7, I*-8, I*-14, I*-15, I*-16, I*-17, I*-18 and I*-19, wherein Z in each case independently has one of the meanings of Z11 as given under formula I and if present twice, preferably one of Z is -COO-, -OCO-, -CH2-O-, -O-CH2-, -CF2-O- or -O-CF2-. In a preferred embodiment the compounds of formula Ia-1 are selected from the following compounds: R11-Phe-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-Phe-R12
Ia-1- 1 R11-Phe-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-Phe-R12
Ia-1- 2 R11-PheL-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-Phe-R12
Ia-1- 3 R11-PheL-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-Phe-R12
Ia-1- 4 R11-PheL-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-PheL-R12
Ia-1- 5 R11-Phe-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-Phe-R12
Ia-1- 6 R11-PheL-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-Phe-R12
Ia-1- 7 R11-PheL-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-PheL-R12
Ia-1- 8 R11-PheL-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-PheL-R12
Ia-1- 9 R11-Phe-Z-Phe-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-Phe-R12
Ia-1- 10 R11-PheL-Z-Phe-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-Phe-R12
Ia-1- 11 R11-Phe-Z-PheL-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-Phe-R12
Ia-1- 12 R11-Phe-Z-Phe-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-Phe-R12
Ia-1- 13 R11-Phe-Z-Phe-Z-Phe-OCF2-(CH2)n-CF2O-PheL-Z-Phe-R12
Ia-1- 14 R11-Phe-Z-Phe-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-PheL-R12
Ia-1- 15 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-Phe-R12
Ia-1- 16 R11-PheL-Z-Phe-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-Phe-R12
Ia-1- 17 R11-PheL-Z-Phe-Z-Phe-OCF2-(CH2)n-CF2O-PheL-Z-Phe-R12
Ia-1- 18 R11-PheL-Z-Phe-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-PheL-R12
Ia-1- 19 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-Phe-R12
Ia-1- 20 R11-Phe-Z-PheL-Z-Phe-OCF2-(CH2)n-CF2O-PheL-Z-Phe-R12
Ia-1- 21 R11-Phe-Z-PheL-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-PheL-R12
Ia-1- 22 R11-Phe-Z-Phe-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-Phe-R12
Ia-1- 23 R11-Phe-Z-Phe-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-PheL-R12
Ia-1- 24 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-Phe-R12
Ia-1- 25 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-CF2O-PheL-Z-Phe-R12
Ia-1- 26 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-PheL-R12
Ia-1- 27 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-Phe-R12
Ia-1- 28 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-PheL-R12
Ia-1- 29 R11-Phe-Z-Phe-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-PheL-R12
Ia-1- 30 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-Phe-R12
Ia-1- 31 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-PheL-R12
Ia-1- 32 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-CF2O-PheL-Z-PheL-R12
Ia-1- 33 R11-PheL-Z-Phe-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-PheL-R12
Ia-1- 34 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-PheL-R12
Ia-1- 35 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-PheL-R12
Ia-1- 36 R11-Phe-Z-Phe-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-Phe-Z-Phe-R12
Ia-1- 37 R11-PheL-Z-Phe-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-Phe-Z-Phe-R12
Ia-1- 38 R11-Phe-Z-PheL-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-Phe-Z-Phe-R12
Ia-1- 39 R11-Phe-Z-Phe-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-Phe-Z-Phe-R12
Ia-1- 40 R11-Phe-Z-Phe-Z-Phe-OCF2-(CH2)n-CF2O-PheL-Z-Phe-Z-Phe-R12
Ia-1- 41 R11-Phe-Z-Phe-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-PheL-Z-Phe-R12
Ia-1- 42 R11-Phe-Z-Phe-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-Phe-Z-PheL-R12
Ia-1- 43 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-Phe-Z-Phe-R12
Ia-1- 44 R11-PheL-Z-Phe-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-Phe-Z-Phe-R12
Ia-1- 45 R11-PheL-Z-Phe-Z-Phe-OCF2-(CH2)n-CF2O-PheL-Z-Phe-Z-Phe-R12
Ia-1- 46 R11-PheL-Z-Phe-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-PheL-Z-Phe-R12
Ia-1- 47 R11-PheL-Z-Phe-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-Phe-Z-PheL-R12
Ia-1- 48 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-Phe-Z-Phe-R12
Ia-1- 49 R11-Phe-Z-PheL-Z-Phe-OCF2-(CH2)n-CF2O-PheL-Z-Phe-Z-Phe-R12
Ia-1- 50 R11-Phe-Z-PheL-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-PheL-Z-Phe-R12
Ia-1- 51 R11-Phe-Z-Phe-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-Phe-Z-Phe-R12
Ia-1- 52 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-Phe-Z-Phe-R12
Ia-1- 53 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-CF2O-PheL-Z-Phe-Z-Phe-R12
Ia-1- 54 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-PheL-Z-Phe-R12
Ia-1- 55 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-CF2O-Phe-Z-Phe-Z-PheL-R12
Ia-1- 56 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-Phe-Z-Phe-R12
Ia-1- 57 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-PheL-Z-Phe-R12
Ia-1- 58 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-Phe-Z-Phe-R12
Ia-1- 59 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-PheL-Z-Phe-R12
Ia-1- 60 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-Phe-Z-PheL-R12
Ia-1- 61 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-PheL-Z-Phe-R12
Ia-1- 62 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-Phe-Z-PheL-Z-PheL-R12
Ia-1- 63 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-PheL-Z-Phe-R12
Ia-1- 64 R11-PheL-Z-Phe-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-PheL-Z-PheL-R12
Ia-1- 65 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-CF2O-PheL-Z-PheL-Z-PheL-R12
Ia-1- 66 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-CF2O-PheL-Z-PheL-Z-PheL-R12
Ia-1- 67 wherein, R11, R12, Phe, PheL, Z and n have one of the meanings as given above. In a preferred embodiment the compounds of formula Ib-1 are selected from the following compounds: R11-Phe-Z-Phe-(CH2)n-CF2O-Phe-Z-Phe-R12 Ib-1- 1 R11-Phe-Z-PheL-OCF2-(CH2)n-Phe-Z-Phe-R12 Ib-1- 2 R11-PheL-Z-Phe-OCF2-(CH2)n-Phe-Z-Phe-R12 Ib-1- 3 R11-Phe-Z-PheL-(CH2)n-CF2O-Phe-Z-Phe-R12 Ib-1- 4 R11-PheL-Z-Phe-(CH2)n-CF2O-Phe-Z-Phe-R12 Ib-1- 5 R11-PheL-Z-PheL-OCF2-(CH2)n-Phe-Z-Phe-R12 Ib-1- 6 R11-PheL-Z-Phe-OCF2-(CH2)n-Phe-Z-PheL-R12 Ib-1- 7 R11-Phe-Z-PheL-OCF2-(CH2)n-PheL-Z-Phe-R12 Ib-1- 8 R11-PheL-Z-PheL-(CH2)n-CF2O-Phe-Z-Phe-R12 Ib-1- 9 R11-PheL-Z-Phe-(CH2)n-CF2O-Phe-Z-PheL-R12 Ib-1- 10 R11-Phe-Z-PheL-(CH2)n-CF2O-PheL-Z-Phe-R12 Ib-1- 11 R11-PheL-Z-PheL-OCF2-(CH2)n-PheL-Z-Phe-R12 Ib-1- 12 R11-PheL-Z-PheL-OCF2-(CH2)n-Phe-Z-PheL-R12 Ib-1- 13 R11-PheL-Z-PheL-(CH2)n-CF2O-PheL-Z-Phe-R12 Ib-1- 14 R11-PheL-Z-PheL-(CH2)n-CF2O-Phe-Z-PheL-R12 Ib-1- 15 R11-PheL-Z-PheL-OCF2-(CH2)n-PheL-Z-PheL-R12 Ib-1- 16 R11-Phe-Z-Phe-Z-Phe-(CH2)n-CF2O-Phe-Z-Phe-R12 Ib-1- 17 R11-Phe-Z-Phe-Z-Phe-OCF2-(CH2)n-Phe-Z-Phe-R12 Ib-1- 18 R11-PheL-Z-Phe-Z-Phe-OCF2-(CH2)n-Phe-Z-Phe-R12 Ib-1- 19 R11-Phe-Z-PheL-Z-Phe-OCF2-(CH2)n-Phe-Z-Phe-R12 Ib-1- 20 R11-Phe-Z-Phe-Z-PheL-OCF2-(CH2)n-Phe-Z-Phe-R12 Ib-1- 21 R11-Phe-Z-Phe-Z-Phe-OCF2-(CH2)n-PheL-Z-Phe-R12 Ib-1- 22 R11-Phe-Z-Phe-Z-Phe-OCF2-(CH2)n-Phe-Z-PheL-R12 Ib-1- 23 R11-PheL-Z-Phe-Z-Phe-(CH2)n-CF2O-Phe-Z-Phe-R12 Ib-1- 24 R11-Phe-Z-PheL-Z-Phe-(CH2)n-CF2O-Phe-Z-Phe-R12 Ib-1- 25 R11-Phe-Z-Phe-Z-PheL-(CH2)n-CF2O-Phe-Z-Phe-R12 Ib-1- 26 R11-Phe-Z-Phe-Z-Phe-(CH2)n-CF2O-PheL-Z-Phe-R12 Ib-1- 27 R11-Phe-Z-Phe-Z-Phe-(CH2)n-CF2O-Phe-Z-PheL-R12 Ib-1- 28 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-Phe-Z-Phe-R12 Ib-1- 29 R11-PheL-Z-Phe-Z-PheL-OCF2-(CH2)n-Phe-Z-Phe-R12 Ib-1- 30 R11-PheL-Z-Phe-Z-Phe-OCF2-(CH2)n-PheL-Z-Phe-R12 Ib-1- 31 R11-PheL-Z-Phe-Z-Phe-OCF2-(CH2)n-Phe-Z-PheL-R12 Ib-1- 32 R11-PheL-Z-PheL-Z-Phe-(CH2)n-CF2O-Phe-Z-Phe-R12 Ib-1- 33 R11-PheL-Z-Phe-Z-PheL-(CH2)n-CF2O-Phe-Z-Phe-R12 Ib-1- 34 R11-PheL-Z-Phe-Z-Phe-(CH2)n-CF2O-PheL-Z-Phe-R12 Ib-1- 35 R11-PheL-Z-Phe-Z-Phe-(CH2)n-CF2O-Phe-Z-PheL-R12 Ib-1- 36 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-Phe-Z-Phe-R12 Ib-1- 37 R11-Phe-Z-PheL-Z-Phe-OCF2-(CH2)n-PheL-Z-Phe-R12 Ib-1- 38 R11-Phe-Z-PheL-Z-Phe-OCF2-(CH2)n-Phe-Z-PheL-R12 Ib-1- 39 R11-Phe-Z-Phe-Z-PheL-OCF2-(CH2)n-PheL-Z-Phe-R12 Ib-1- 40 R11-Phe-Z-Phe-Z-PheL-OCF2-(CH2)n-Phe-Z-PheL-R12 Ib-1- 41 R11-Phe-Z-PheL-Z-PheL(CH2)n-CF2O-Phe-Z-Phe-R12 Ib-1- 42 R11-Phe-Z-PheL-Z-Phe-(CH2)n-CF2O-PheL-Z-Phe-R12 Ib-1- 43 R11-Phe-Z-PheL-Z-Phe-(CH2)n-CF2O-Phe-Z-PheL-R12 Ib-1- 44 R11-Phe-Z-Phe-Z-PheL-(CH2)n-CF2O-PheL-Z-Phe-R12 Ib-1- 45 R11-Phe-Z-Phe-Z-PheL-(CH2)n-CF2O-Phe-Z-PheL-R12 Ib-1- 46 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-Phe-Z-Phe-R12 Ib-1- 47 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-PheL-Z-Phe-R12 Ib-1- 48 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-Phe-Z-PheL-R12 Ib-1- 49 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-PheL-Z-Phe-R12 Ib-1- 50 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-Phe-Z-PheL-R12 Ib-1- 51 R11-Phe-Z-Phe-Z-PheL-OCF2-(CH2)n-PheL-Z-PheL-R12 Ib-1- 52 R11-PheL-Z-PheL-Z-PheL-(CH2)n-CF2O-Phe-Z-Phe-R12 Ib-1- 53 R11-PheL-Z-PheL-Z-Phe-(CH2)n-CF2O-PheL-Z-Phe-R12 Ib-1- 54 R11-PheL-Z-PheL-Z-Phe-(CH2)n-CF2O-Phe-Z-PheL-R12 Ib-1- 55 R11-Phe-Z-PheL-Z-PheL-(CH2)n-CF2O-PheL-Z-Phe-R12 Ib-1- 56 R11-Phe-Z-PheL-Z-PheL-(CH2)n-CF2O-Phe-Z-PheL-R12 Ib-1- 57 R11-Phe-Z-Phe-Z-PheL-(CH2)n-CF2O-PheL-Z-PheL-R12 Ib-1- 58 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-PheL-Z-Phe-R12 Ib-1- 59 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-Phe-Z-PheL-R12 Ib-1- 60 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-PheL-Z-PheL-R12 Ib-1- 61 R11-PheL-Z-Phe-Z-PheL-OCF2-(CH2)n-PheL-Z-PheL-R12 Ib-1- 62 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-PheL-Z-PheL-R12 Ib-1- 63 R11-PheL-Z-PheL-Z-PheL-(CH2)n-CF2O-PheL-Z-Phe-R12 Ib-1- 64 R11-PheL-Z-PheL-Z-PheL-(CH2)n-CF2O-Phe-Z-PheL-R12 Ib-1- 65 R11-PheL-Z-PheL-Z-Phe-(CH2)n-CF2O-PheL-Z-PheL-R12 Ib-1- 66 R11-PheL-Z-Phe-Z-PheL-(CH2)n-CF2O-PheL-Z-PheL-R12 Ib-1- 67 R11-Phe-Z-PheL-Z-PheL-(CH2)n-CF2O-PheL-Z-PheL-R12 Ib-1- 68 R11-PheL-Z-PheL-Z-PheL-(CH2)n-CF2O-PheL-Z-PheL-R12 Ib-1- 69 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)nPheL-Z-PheL-R12 Ib-1- 70 R11-Phe-Z-Phe-Z-Phe-OCF2-(CH2)n-Phe-Z-Phe-Z-Phe-R12 Ib-1- 71 R11-PheL-Z-Phe-Z-Phe-(CH2)n-CF2O-Phe-Z-Phe-Z-Phe-R12 Ib-1- 72 R11-Phe-Z-PheL-Z-Phe-(CH2)n-CF2O-Phe-Z-Phe-Z-Phe-R12 Ib-1- 73 R11-Phe-Z-Phe-Z-PheL-(CH2)n-CF2O-Phe-Z-Phe-Z-Phe-R12 Ib-1- 74 R11-Phe-Z-Phe-Z-Phe-(CH2)n-CF2O-PheL-Z-Phe-Z-Phe-R12 Ib-1- 75 R11-Phe-Z-Phe-Z-Phe-(CH2)n-CF2O-Phe-Z-PheL-Z-Phe-R12 Ib-1- 76 R11-Phe-Z-Phe-Z-Phe-(CH2)n-CF2O-Phe-Z-Phe-Z-PheL-R12 Ib-1- 77 R11-PheL-Z-Phe-Z-Phe-OCF2-(CH2)n-Phe-Z-Phe-Z-Phe-R12 Ib-1- 78 R11-Phe-Z-PheL-Z-Phe-OCF2-(CH2)n-Phe-Z-Phe-Z-Phe-R12 Ib-1- 79 R11-Phe-Z-Phe-Z-PheL-OCF2-(CH2)n-Phe-Z-Phe-Z-Phe-R12 Ib-1- 80 R11-Phe-Z-Phe-Z-Phe-OCF2-(CH2)n-PheL-Z-Phe-Z-Phe-R12 Ib-1- 81 R11-Phe-Z-Phe-Z-Phe-OCF2-(CH2)n-Phe-Z-PheL-Z-Phe-R12 Ib-1- 82 R11-Phe-Z-Phe-Z-Phe-OCF2-(CH2)n-Phe-Z-Phe-Z-PheL-R12 Ib-1- 83 R11-PheL-Z-PheL-Z-Phe-(CH2)n-CF2O-Phe-Z-Phe-Z-Phe-R12 Ib-1- 84 R11-PheL-Z-Phe-Z-PheL-(CH2)n-CF2O-Phe-Z-Phe-Z-Phe-R12 Ib-1- 85 R11-PheL-Z-Phe-Z-Phe-(CH2)n-CF2O-PheL-Z-Phe-Z-Phe-R12 Ib-1- 86 R11-PheL-Z-Phe-Z-Phe-(CH2)n-CF2O-Phe-Z-PheL-Z-Phe-R12 Ib-1- 87 R11-PheL-Z-Phe-Z-Phe-(CH2)n-CF2O-Phe-Z-Phe-Z-PheL-R12 Ib-1- 88 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-Phe-Z-Phe-Z-Phe-R12 Ib-1- 89 R11-PheL-Z-Phe-Z-PheL-OCF2-(CH2)n-Phe-Z-Phe-Z-Phe-R12 Ib-1- 90 R11-PheL-Z-Phe-Z-Phe-OCF2-(CH2)n-PheL-Z-Phe-Z-Phe-R12 Ib-1- 91 R11-PheL-Z-Phe-Z-Phe-OCF2-(CH2)n-Phe-Z-PheL-Z-Phe-R12 Ib-1- 92 R11-PheL-Z-Phe-Z-Phe-OCF2-(CH2)n-Phe-Z-Phe-Z-PheL-R12 Ib-1- 93 R11-Phe-Z-PheL-Z-PheL-(CH2)n-CF2O-Phe-Z-Phe-Z-Phe-R12 Ib-1- 94 R11-Phe-Z-PheL-Z-Phe-(CH2)n-CF2O-PheL-Z-Phe-Z-Phe-R12 Ib-1- 95 R11-Phe-Z-PheL-Z-Phe-(CH2)n-CF2O-Phe-Z-PheL-Z-Phe-R12 Ib-1- 96 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-Phe-Z-Phe-Z-Phe-R12 Ib-1- 97 R11-Phe-Z-PheL-Z-Phe-OCF2-(CH2)n-PheL-Z-Phe-Z-Phe-R12 Ib-1- 98 R11-Phe-Z-PheL-Z-Phe-OCF2-(CH2)n-Phe-Z-PheL-Z-Phe-R12 Ib-1- 99 R11-Phe-Z-Phe-Z-PheL-OCF2-(CH2)n-PheL-Z-Phe-Z-Phe-R12 Ib-1- 100 R11-PheL-Z-PheL-Z-PheL-(CH2)n-CF2O-Phe-Z-Phe-Z-Phe-R12 Ib-1- 101 R11-PheL-Z-PheL-Z-Phe-(CH2)n-CF2O-PheL-Z-Phe-Z-Phe-R12 Ib-1- 102 R11-PheL-Z-PheL-Z-Phe-(CH2)n-CF2O-Phe-Z-PheL-Z-Phe-R12 Ib-1- 103 R11-PheL-Z-PheL-Z-Phe-(CH2)n-CF2O-Phe-Z-Phe-Z-PheL-R12 Ib-1- 104 R11-Phe-Z-PheL-Z-PheL-(CH2)n-CF2O-PheL-Z-Phe-Z-Phe-R12 Ib-1- 105 R11-Phe-Z-PheL-Z-PheL-(CH2)n-CF2O-Phe-Z-PheL-Z-Phe-R12 Ib-1- 106 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-Phe-Z-Phe-Z-Phe-R12 Ib-1- 107 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-PheL-Z-Phe-Z-Phe-R12 Ib-1- 108 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-Phe-Z-PheL-Z-Phe-R12 Ib-1- 109 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-Phe-Z-Phe-Z-PheL-R12 Ib-1- 110 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-PheL-Z-Phe-Z-Phe-R12 Ib-1- 111 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-Phe-Z-PheL-Z-Phe-R12 Ib-1- 112 R11-PheL-Z-PheL-Z-PheL-(CH2)n-CF2O-PheL-Z-Phe-Z-Phe-R12 Ib-1- 113 R11-PheL-Z-PheL-Z-PheL-(CH2)n-CF2O-Phe-Z-PheL-Z-Phe-R12 Ib-1- 114 R11-PheL-Z-PheL-Z-PheL-(CH2)n-CF2O-Phe-Z-Phe-Z-PheL-R12 Ib-1- 115 R11-Phe-Z-PheL-Z-PheL-(CH2)n-CF2O-PheL-Z-PheL-Z-Phe-R12 Ib-1- 116 R11-Phe-Z-PheL-Z-PheL-(CH2)n-CF2O-Phe-Z-PheL-Z-PheL-R12 Ib-1- 117 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-PheL-Z-Phe-Z-Phe-R12 Ib-1- 118 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-Phe-Z-PheL-Z-Phe-R12 Ib-1- 119 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-Phe-Z-Phe-Z-PheL-R12 Ib-1- 120 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-PheL-Z-PheL-Z-Phe-R12 Ib-1- 121 R11-Phe-Z-PheL-Z-PheL-OCF2-(CH2)n-Phe-Z-PheL-Z-PheL-R12 Ib-1- 122 R11-PheL-Z-PheL-Z-PheL-(CH2)n-CF2O-PheL-Z-PheL-Z-Phe-R12 Ib-1- 123 R11-PheL-Z-Phe-Z-PheL-(CH2)n-CF2O-PheL-Z-PheL-Z-PheL-R12 Ib-1- 124 R11-PheL-Z-PheL-Z-Phe-(CH2)n-CF2O-PheL-Z-PheL-Z-PheL-R12 Ib-1- 125 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-PheL-Z-PheL-Z-Phe-R12 Ib-1- 126 R11-PheL-Z-Phe-Z-PheL-OCF2-(CH2)n-PheL-Z-PheL-Z-PheL-R12 Ib-1- 127 R11-PheL-Z-PheL-Z-Phe-OCF2-(CH2)n-PheL-Z-PheL-Z-PheL-R12 Ib-1- 128 R11-PheL-Z-PheL-Z-PheL-OCF2-(CH2)n-PheL-Z-PheL-Z-PheL-R12 Ib-1- 129 wherein, R11, R12, Phe, PheL, Z and n have one of the meanings as given above. Further preferred compounds of formula Ia-1 are selected from the group of compounds with the following formulae: R11-Phe-Phe-OCF2-(CH2)n-CF2O-Phe-Phe-R12
Ia-1- 1 a R11-Phe-PheL-OCF2-(CH2)n-CF2O-Phe-Phe-R12
Ia-1- 2 a R11-PheL-Phe-OCF2-(CH2)n-CF2O-Phe-Phe-R12
Ia-1- 3 a R11-PheL-PheL-OCF2-(CH2)n-CF2O-Phe-Phe-R12
Ia-1- 4 a R11-PheL-Phe-OCF2-(CH2)n-CF2O-Phe-PheL-R12
Ia-1- 5 a R11-Phe-PheL-OCF2-(CH2)n-CF2O-PheL-Phe-R12
Ia-1- 6 a R11-PheL-PheL-OCF2-(CH2)n-CF2O-PheL-Phe-R12
Ia-1- 7 a R11-PheL-PheL-OCF2-(CH2)n-CF2O-Phe-PheL-R12
Ia-1- 8 a R11-PheL-PheL-OCF2-(CH2)n-CF2O-PheL-PheL-R12
Ia-1- 9 a R11-Phe-Phe-Phe-OCF2-(CH2)n-CF2O-Phe-Phe-R12
Ia-1- 10 a R11-PheL-Phe-Phe-OCF2-(CH2)n-CF2O-Phe-Phe-R12
Ia-1- 11 a R11-Phe-PheL-Phe-OCF2-(CH2)n-CF2O-Phe-Phe-R12
Ia-1- 12 a R11-Phe-Phe-PheL-OCF2-(CH2)n-CF2O-Phe-Phe-R12
Ia-1- 13 a R11-Phe-Phe-Phe-OCF2-(CH2)n-CF2O-PheL-Phe-R12
Ia-1- 14 a R11-Phe-Phe-Phe-OCF2-(CH2)n-CF2O-Phe-PheL-R12
Ia-1- 15 a R11-PheL-PheL-Phe-OCF2-(CH2)n-CF2O-Phe-Phe-R12
Ia-1- 16 a R11-PheL-Phe-PheL-OCF2-(CH2)n-CF2O-Phe-Phe-R12
Ia-1- 17 a R11-PheL-Phe-Phe-OCF2-(CH2)n-CF2O-PheL-Phe-R12
Ia-1- 18 a R11-PheL-Phe-Phe-OCF2-(CH2)n-CF2O-Phe-PheL-R12
Ia-1- 19 a R11-Phe-PheL-PheL-OCF2-(CH2)n-CF2O-Phe-Phe-R12
Ia-1- 20 a R11-Phe-PheL-Phe-OCF2-(CH2)n-CF2O-PheL-Phe-R12
Ia-1- 21 a R11-Phe-PheL-Phe-OCF2-(CH2)n-CF2O-Phe-PheL-R12
Ia-1- 22 a R11-Phe-Phe-PheL-OCF2-(CH2)n-CF2O-PheL-Phe-R12
Ia-1- 23 a R11-Phe-Phe-PheL-OCF2-(CH2)n-CF2O-Phe-PheL-R12
Ia-1- 24 a R11-PheL-PheL-PheL-OCF2-(CH2)n-CF2O-Phe-Phe-R12
Ia-1- 25 a R11-PheL-PheL-Phe-OCF2-(CH2)n-CF2O-PheL-Phe-R12
Ia-1- 26 a R11-PheL-PheL-Phe-OCF2-(CH2)n-CF2O-Phe-PheL-R12
Ia-1- 27 a R11-Phe-PheL-PheL-OCF2-(CH2)n-CF2O-PheL-Phe-R12
Ia-1- 28 a R11-Phe-PheL-PheL-OCF2-(CH2)n-CF2O-Phe-PheL-R12
Ia-1- 29 a R11-Phe-Phe-PheL-OCF2-(CH2)n-CF2O-PheL-PheL-R12
Ia-1- 30 a R11-PheL-PheL-PheL-OCF2-(CH2)n-CF2O-PheL-Phe-R12
Ia-1- 31 a R11-PheL-PheL-PheL-OCF2-(CH2)n-CF2O-Phe-PheL-R12
Ia-1- 32 a R11-PheL-PheL-Phe-OCF2-(CH2)n-CF2O-PheL-PheL-R12
Ia-1- 33 a R11-PheL-Phe-PheL-OCF2-(CH2)n-CF2O-PheL-PheL-R12
Ia-1- 34 a R11-Phe-PheL-PheL-OCF2-(CH2)n-CF2O-PheL-PheL-R12
Ia-1- 35 a R11-PheL-PheL-PheL-OCF2-(CH2)n-CF2O-PheL-PheL-R12
Ia-1- 36 a R11-Phe-Phe-Phe-OCF2-(CH2)n-CF2O-Phe-Phe-Phe-R12
Ia-1- 37 a R11-PheL-Phe-Phe-OCF2-(CH2)n-CF2O-Phe-Phe-Phe-R12
Ia-1- 38 a R11-Phe-PheL-Phe-OCF2-(CH2)n-CF2O-Phe-Phe-Phe-R12
Ia-1- 39 a R11-Phe-Phe-PheL-OCF2-(CH2)n-CF2O-Phe-Phe-Phe-R12
Ia-1- 40 a R11-Phe-Phe-Phe-OCF2-(CH2)n-CF2O-PheL-Phe-Phe-R12
Ia-1- 41 a R11-Phe-Phe-Phe-OCF2-(CH2)n-CF2O-Phe-PheL-Phe-R12
Ia-1- 42 a R11-Phe-Phe-Phe-OCF2-(CH2)n-CF2O-Phe-Phe-PheL-R12
Ia-1- 43 a R11-PheL-PheL-Phe-OCF2-(CH2)n-CF2O-Phe-Phe-Phe-R12
Ia-1- 44 a R11-PheL-Phe-PheL-OCF2-(CH2)n-CF2O-Phe-Phe-Phe-R12
Ia-1- 45 a R11-PheL-Phe-Phe-OCF2-(CH2)n-CF2O-PheL-Phe-Phe-R12
Ia-1- 46 a R11-PheL-Phe-Phe-OCF2-(CH2)n-CF2O-Phe-PheL-Phe-R12
Ia-1- 47 a R11-PheL-Phe-Phe-OCF2-(CH2)n-CF2O-Phe-Phe-PheL-R12
Ia-1- 48 a R11-Phe-PheL-PheL-OCF2-(CH2)n-CF2O-Phe-Phe-Phe-R12
Ia-1- 49 a R11-Phe-PheL-Phe-OCF2-(CH2)n-CF2O-PheL-Phe-Phe-R12
Ia-1- 50 a R11-Phe-PheL-Phe-OCF2-(CH2)n-CF2O-Phe-PheL-Phe-R12
Ia-1- 51 a R11-Phe-Phe-PheL-OCF2-(CH2)n-CF2O-PheL-Phe-Phe-R12
Ia-1- 52 a R11-PheL-PheL-PheL-OCF2-(CH2)n-CF2O-Phe-Phe-Phe-R12
Ia-1- 53 a R11-PheL-PheL-Phe-OCF2-(CH2)n-CF2O-PheL-Phe-Phe-R12
Ia-1- 54 a R11-PheL-PheL-Phe-OCF2-(CH2)n-CF2O-Phe-PheL-Phe-R12
Ia-1- 55 a R11-PheL-PheL-Phe-OCF2-(CH2)n-CF2O-Phe-Phe-PheL-R12
Ia-1- 56 a R11-Phe-PheL-PheL-OCF2-(CH2)n-CF2O-PheL-Phe-Phe-R12
Ia-1- 57 a R11-Phe-PheL-PheL-OCF2-(CH2)n-CF2O-Phe-PheL-Phe-R12
Ia-1- 58 a R11-PheL-PheL-PheL-OCF2-(CH2)n-CF2O-PheL-Phe-Phe-R12
Ia-1- 59 a R11-PheL-PheL-PheL-OCF2-(CH2)n-CF2O-Phe-PheL-Phe-R12
Ia-1- 60 a R11-PheL-PheL-PheL-OCF2-(CH2)n-CF2O-Phe-Phe-PheL-R12
Ia-1- 61 a R11-Phe-PheL-PheL-OCF2-(CH2)n-CF2O-PheL-PheL-Phe-R12
Ia-1- 62 a R11-Phe-PheL-PheL-OCF2-(CH2)n-CF2O-Phe-PheL-PheL-R12
Ia-1- 63 a R11-PheL-PheL-PheL-OCF2-(CH2)n-CF2O-PheL-PheL-Phe-R12
Ia-1- 64 a R11-PheL-Phe-PheL-OCF2-(CH2)n-CF2O-PheL-PheL-PheL-R12
Ia-1- 65 a R11-PheL-PheL-Phe-OCF2-(CH2)n-CF2O-PheL-PheL-PheL-R12
Ia-1- 66 a R11-PheL-PheL-PheL-OCF2-(CH2)n-CF2O-PheL-PheL-PheL-R12
Ia-1- 67 a wherein, R11, R12, Phe and PheL have one of the meanings as given above and n denotes 5, 7, 9 or 11. Further preferred compounds of formula Ib-1 are selected from the following compounds: R11-Phe-Phe-(CH2)n-CF2O-Phe-Phe-R12 Ib-1- 1 a R11-Phe-PheL-OCF2-(CH2)n-Phe-Phe-R12 Ib-1- 2 a R11-PheL-Phe-OCF2-(CH2)n-Phe-Phe-R12 Ib-1- 3 a R11-Phe-PheL-(CH2)n-CF2O-Phe-Phe-R12 Ib-1- 4 a R11-PheL-Phe-(CH2)n-CF2O-Phe-Phe-R12 Ib-1- 5 a R11-PheL-PheL-OCF2-(CH2)n-Phe-Phe-R12 Ib-1- 6 a R11-PheL-Phe-OCF2-(CH2)n-Phe-PheL-R12 Ib-1- 7 a R11-Phe-PheL-OCF2-(CH2)n-PheL-Phe-R12 Ib-1- 8 a R11-PheL-PheL-(CH2)n-CF2O-Phe-Phe-R12 Ib-1- 9 a R11-PheL-Phe-(CH2)n-CF2O-Phe-PheL-R12 Ib-1- 10 a R11-Phe-PheL-(CH2)n-CF2O-PheL-Phe-R12 Ib-1- 11 a R11-PheL-PheL-OCF2-(CH2)n-PheL-Phe-R12 Ib-1- 12 a R11-PheL-PheL-OCF2-(CH2)n-Phe-PheL-R12 Ib-1- 13 a R11-PheL-PheL-(CH2)n-CF2O-PheL-Phe-R12 Ib-1- 14 a R11-PheL-PheL-(CH2)n-CF2O-Phe-PheL-R12 Ib-1- 15 a R11-PheL-PheL-OCF2-(CH2)n-PheL-PheL-R12 Ib-1- 16 a R11-Phe-Phe-Phe-(CH2)n-CF2O-Phe-Phe-R12 Ib-1- 17 a R11-Phe-Phe-Phe-OCF2-(CH2)n-Phe-Phe-R12 Ib-1- 18 a R11-PheL-Phe-Phe-OCF2-(CH2)n-Phe-Phe-R12 Ib-1- 19 a R11-Phe-PheL-Phe-OCF2-(CH2)n-Phe-Phe-R12 Ib-1- 20 a R11-Phe-Phe-PheL-OCF2-(CH2)n-Phe-Phe-R12 Ib-1- 21 a R11-Phe-Phe-Phe-OCF2-(CH2)n-PheL-Phe-R12 Ib-1- 22 a R11-Phe-Phe-Phe-OCF2-(CH2)n-Phe-PheL-R12 Ib-1- 23 a R11-PheL-Phe-Phe-(CH2)n-CF2O-Phe-Phe-R12 Ib-1- 24 a R11-Phe-PheL-Phe-(CH2)n-CF2O-Phe-Phe-R12 Ib-1- 25 a R11-Phe-Phe-PheL-(CH2)n-CF2O-Phe-Phe-R12 Ib-1- 26 a R11-Phe-Phe-Phe-(CH2)n-CF2O-PheL-Phe-R12 Ib-1- 27 a R11-Phe-Phe-Phe-(CH2)n-CF2O-Phe-PheL-R12 Ib-1- 28 a R11-PheL-PheL-Phe-OCF2-(CH2)n-Phe-Phe-R12 Ib-1- 29 a R11-PheL-Phe-PheL-OCF2-(CH2)n-Phe-Phe-R12 Ib-1- 30 a R11-PheL-Phe-Phe-OCF2-(CH2)n-PheL-Phe-R12 Ib-1- 31 a R11-PheL-Phe-Phe-OCF2-(CH2)n-Phe-PheL-R12 Ib-1- 32 a R11-PheL-PheL-Phe-(CH2)n-CF2O-Phe-Phe-R12 Ib-1- 33 a R11-PheL-Phe-PheL-(CH2)n-CF2O-Phe-Phe-R12 Ib-1- 34 a R11-PheL-Phe-Phe-(CH2)n-CF2O-PheL-Phe-R12 Ib-1- 35 a R11-PheL-Phe-Phe-(CH2)n-CF2O-Phe-PheL-R12 Ib-1- 36 a R11-Phe-PheL-PheL-OCF2-(CH2)n-Phe-Phe-R12 Ib-1- 37 a R11-Phe-PheL-Phe-OCF2-(CH2)n-PheL-Phe-R12 Ib-1- 38 a R11-Phe-PheL-Phe-OCF2-(CH2)n-Phe-PheL-R12 Ib-1- 39 a R11-Phe-Phe-PheL-OCF2-(CH2)n-PheL-Phe-R12 Ib-1- 40 a R11-Phe-Phe-PheL-OCF2-(CH2)n-Phe-PheL-R12 Ib-1- 41 a R11-Phe-PheL-PheL(CH2)n-CF2O-Phe-Phe-R12 Ib-1- 42 a R11-Phe-PheL-Phe-(CH2)n-CF2O-PheL-Phe-R12 Ib-1- 43 a R11-Phe-PheL-Phe-(CH2)n-CF2O-Phe-PheL-R12 Ib-1- 44 a R11-Phe-Phe-PheL-(CH2)n-CF2O-PheL-Phe-R12 Ib-1- 45 a R11-Phe-Phe-PheL-(CH2)n-CF2O-Phe-PheL-R12 Ib-1- 46 a R11-PheL-PheL-PheL-OCF2-(CH2)n-Phe-Phe-R12 Ib-1- 47 a R11-PheL-PheL-Phe-OCF2-(CH2)n-PheL-Phe-R12 Ib-1- 48 a R11-PheL-PheL-Phe-OCF2-(CH2)n-Phe-PheL-R12 Ib-1- 49 a R11-Phe-PheL-PheL-OCF2-(CH2)n-PheL-Phe-R12 Ib-1- 50 a R11-Phe-PheL-PheL-OCF2-(CH2)n-Phe-PheL-R12 Ib-1- 51 a R11-Phe-Phe-PheL-OCF2-(CH2)n-PheL-PheL-R12 Ib-1- 52 a R11-PheL-PheL-PheL-(CH2)n-CF2O-Phe-Phe-R12 Ib-1- 53 a R11-PheL-PheL-Phe-(CH2)n-CF2O-PheL-Phe-R12 Ib-1- 54 a R11-PheL-PheL-Phe-(CH2)n-CF2O-Phe-PheL-R12 Ib-1- 55 a R11-Phe-PheL-PheL-(CH2)n-CF2O-PheL-Phe-R12 Ib-1- 56 a R11-Phe-PheL-PheL-(CH2)n-CF2O-Phe-PheL-R12 Ib-1- 57 a R11-Phe-Phe-PheL-(CH2)n-CF2O-PheL-PheL-R12 Ib-1- 58 a R11-PheL-PheL-PheL-OCF2-(CH2)n-PheL-Phe-R12 Ib-1- 59 a R11-PheL-PheL-PheL-OCF2-(CH2)n-Phe-PheL-R12 Ib-1- 60 a R11-PheL-PheL-Phe-OCF2-(CH2)n-PheL-PheL-R12 Ib-1- 61 a R11-PheL-Phe-PheL-OCF2-(CH2)n-PheL-PheL-R12 Ib-1- 62 a R11-Phe-PheL-PheL-OCF2-(CH2)n-PheL-PheL-R12 Ib-1- 63 a R11-PheL-PheL-PheL-(CH2)n-CF2O-PheL-Phe-R12 Ib-1- 64 a R11-PheL-PheL-PheL-(CH2)n-CF2O-Phe-PheL-R12 Ib-1- 65 a R11-PheL-PheL-Phe-(CH2)n-CF2O-PheL-PheL-R12 Ib-1- 66 a R11-PheL-Phe-PheL-(CH2)n-CF2O-PheL-PheL-R12 Ib-1- 67 a R11-Phe-PheL-PheL-(CH2)n-CF2O-PheL-PheL-R12 Ib-1- 68 a R11-PheL-PheL-PheL-(CH2)n-CF2O-PheL-PheL-R12 Ib-1- 69 a R11-PheL-PheL-PheL-OCF2-(CH2)nPheL-PheL-R12 Ib-1- 70 a R11-Phe-Phe-Phe-OCF2-(CH2)n-Phe-Phe-Phe-R12 Ib-1- 71 a R11-PheL-Phe-Phe-(CH2)n-CF2O-Phe-Phe-Phe-R12 Ib-1- 72 a R11-Phe-PheL-Phe-(CH2)n-CF2O-Phe-Phe-Phe-R12 Ib-1- 73 a R11-Phe-Phe-PheL-(CH2)n-CF2O-Phe-Phe-Phe-R12 Ib-1- 74 a R11-Phe-Phe-Phe-(CH2)n-CF2O-PheL-Phe-Phe-R12 Ib-1- 75 a R11-Phe-Phe-Phe-(CH2)n-CF2O-Phe-PheL-Phe-R12 Ib-1- 76 a R11-Phe-Phe-Phe-(CH2)n-CF2O-Phe-Phe-PheL-R12 Ib-1- 77 a R11-PheL-Phe-Phe-OCF2-(CH2)n-Phe-Phe-Phe-R12 Ib-1- 78 a R11-Phe-PheL-Phe-OCF2-(CH2)n-Phe-Phe-Phe-R12 Ib-1- 79 a R11-Phe-Phe-PheL-OCF2-(CH2)n-Phe-Phe-Phe-R12 Ib-1- 80 a R11-Phe-Phe-Phe-OCF2-(CH2)n-PheL-Phe-Phe-R12 Ib-1- 81 a R11-Phe-Phe-Phe-OCF2-(CH2)n-Phe-PheL-Phe-R12 Ib-1- 82 a R11-Phe-Phe-Phe-OCF2-(CH2)n-Phe-Phe-PheL-R12 Ib-1- 83 a R11-PheL-PheL-Phe-(CH2)n-CF2O-Phe-Phe-Phe-R12 Ib-1- 84 a R11-PheL-Phe-PheL-(CH2)n-CF2O-Phe-Phe-Phe-R12 Ib-1- 85 a R11-PheL-Phe-Phe-(CH2)n-CF2O-PheL-Phe-Phe-R12 Ib-1- 86 a R11-PheL-Phe-Phe-(CH2)n-CF2O-Phe-PheL-Phe-R12 Ib-1- 87 a R11-PheL-Phe-Phe-(CH2)n-CF2O-Phe-Phe-PheL-R12 Ib-1- 88 a R11-PheL-PheL-Phe-OCF2-(CH2)n-Phe-Phe-Phe-R12 Ib-1- 89 a R11-PheL-Phe-PheL-OCF2-(CH2)n-Phe-Phe-Phe-R12 Ib-1- 90 a R11-PheL-Phe-Phe-OCF2-(CH2)n-PheL-Phe-Phe-R12 Ib-1- 91 a R11-PheL-Phe-Phe-OCF2-(CH2)n-Phe-PheL-Phe-R12 Ib-1- 92 a R11-PheL-Phe-Phe-OCF2-(CH2)n-Phe-Phe-PheL-R12 Ib-1- 93 a R11-Phe-PheL-PheL-(CH2)n-CF2O-Phe-Phe-Phe-R12 Ib-1- 94 a R11-Phe-PheL-Phe-(CH2)n-CF2O-PheL-Phe-Phe-R12 Ib-1- 95 a R11-Phe-PheL-Phe-(CH2)n-CF2O-Phe-PheL-Phe-R12 Ib-1- 96 a R11-Phe-PheL-PheL-OCF2-(CH2)n-Phe-Phe-Phe-R12 Ib-1- 97 a R11-Phe-PheL-Phe-OCF2-(CH2)n-PheL-Phe-Phe-R12 Ib-1- 98 a R11-Phe-PheL-Phe-OCF2-(CH2)n-Phe-PheL-Phe-R12 Ib-1- 99 a R11-Phe-Phe-PheL-OCF2-(CH2)n-PheL-Phe-Phe-R12 Ib-1- 100 a R11-PheL-PheL-PheL-(CH2)n-CF2O-Phe-Phe-Phe-R12 Ib-1- 101 a R11-PheL-PheL-Phe-(CH2)n-CF2O-PheL-Phe-Phe-R12 Ib-1- 102 a R11-PheL-PheL-Phe-(CH2)n-CF2O-Phe-PheL-Phe-R12 Ib-1- 103 a R11-PheL-PheL-Phe-(CH2)n-CF2O-Phe-Phe-PheL-R12 Ib-1- 104 a R11-Phe-PheL-PheL-(CH2)n-CF2O-PheL-Phe-Phe-R12 Ib-1- 105 a R11-Phe-PheL-PheL-(CH2)n-CF2O-Phe-PheL-Phe-R12 Ib-1- 106 a R11-PheL-PheL-PheL-OCF2-(CH2)n-Phe-Phe-Phe-R12 Ib-1- 107 a R11-PheL-PheL-Phe-OCF2-(CH2)n-PheL-Phe-Phe-R12 Ib-1- 108 a R11-PheL-PheL-Phe-OCF2-(CH2)n-Phe-PheL-Phe-R12 Ib-1- 109 a R11-PheL-PheL-Phe-OCF2-(CH2)n-Phe-Phe-PheL-R12 Ib-1- 110 a R11-Phe-PheL-PheL-OCF2-(CH2)n-PheL-Phe-Phe-R12 Ib-1- 111 a R11-Phe-PheL-PheL-OCF2-(CH2)n-Phe-PheL-Phe-R12 Ib-1- 112 a R11-PheL-PheL-PheL-(CH2)n-CF2O-PheL-Phe-Phe-R12 Ib-1- 113 a R11-PheL-PheL-PheL-(CH2)n-CF2O-Phe-PheL-Phe-R12 Ib-1- 114 a R11-PheL-PheL-PheL-(CH2)n-CF2O-Phe-Phe-PheL-R12 Ib-1- 115 a R11-Phe-PheL-PheL-(CH2)n-CF2O-PheL-PheL-Phe-R12 Ib-1- 116 a R11-Phe-PheL-PheL-(CH2)n-CF2O-Phe-PheL-PheL-R12 Ib-1- 117 a R11-PheL-PheL-PheL-OCF2-(CH2)n-PheL-Phe-Phe-R12 Ib-1- 118 a R11-PheL-PheL-PheL-OCF2-(CH2)n-Phe-PheL-Phe-R12 Ib-1- 119 a R11-PheL-PheL-PheL-OCF2-(CH2)n-Phe-Phe-PheL-R12 Ib-1- 120 a R11-Phe-PheL-PheL-OCF2-(CH2)n-PheL-PheL-Phe-R12 Ib-1- 121 a R11-Phe-PheL-PheL-OCF2-(CH2)n-Phe-PheL-PheL-R12 Ib-1- 122 a R11-PheL-PheL-PheL-(CH2)n-CF2O-PheL-PheL-Phe-R12 Ib-1- 123 a R11-PheL-Phe-PheL-(CH2)n-CF2O-PheL-PheL-PheL-R12 Ib-1- 124 a R11-PheL-PheL-Phe-(CH2)n-CF2O-PheL-PheL-PheL-R12 Ib-1- 125 a R11-PheL-PheL-PheL-OCF2-(CH2)n-PheL-PheL-Phe-R12 Ib-1- 126 a R11-PheL-Phe-PheL-OCF2-(CH2)n-PheL-PheL-PheL-R12 Ib-1- 127 a R11-PheL-PheL-Phe-OCF2-(CH2)n-PheL-PheL-PheL-R12 Ib-1- 128 a R11-PheL-PheL-PheL-OCF2-(CH2)n-PheL-PheL-PheL-R12 Ib-1- 129 a wherein, R11, R12, Phe and PheL have one of the meanings as given above and n denotes 5,7, 9 or 11. In the above given preferred subformulae of formula I, PheL preferably
(L) denotes the group
Figure imgf000034_0002
The group
denoting
Figure imgf000034_0001
Figure imgf000035_0001
wherein L is preferably F, Cl, CH3, OCH3 and COCH3.
Thus, further preferred compounds of formula Ia-1 are selected, for example, from the following compounds:
Figure imgf000035_0002
Figure imgf000036_0001
R11, R12 have one of the meanings as given above, preferably both R11 and R12 are identical and denote both CN or F, likewise preferably R11 and R12 are different and at least one of them denote CN or F and n preferably denotes 7 or 9. Further preferred compounds are of formula Ib-1, for example, are preferably selected from the following compounds:
Figure imgf000036_0002
Figure imgf000037_0001
Figure imgf000038_0001
Figure imgf000039_0001
Figure imgf000040_0001
R11, R12 have one of the meanings as given above, preferably both R11 and R12 are identical and denote both CN or F, likewise preferably R11 and R12 are different and at least one of them denote CN or F and n preferably denotes 7 or 9. The compounds of formula I can be synthesized according to or in analogy to methods which are known per se and which are described in standard works of organic chemistry such as, for example, Houben-Weyl, Methoden der organischen Chemie, Thieme-Verlag, Stuttgart. In a preferred embodiment, the compounds of formula Ia-1 can be s nthesized accordin to or in analo to the followin s nthesis scheme:
Figure imgf000040_0002
wherein the given parameters have one of the meanings as given above under formula Ia-1. Thus, the invention relates also to a method of production of compounds of formula Ia-1 com risin at least the step of reacting a compound of
Figure imgf000041_0001
with one or more compounds of formula R11-MG11-OH or R12-MG12-OH, wherein the parameters have one of the meanings as given above under formula Ia-1. In another preferred embodiment, the compounds of formula Ib-1 can be synthesized according to or in analogy to the following synthesis scheme:
Figure imgf000041_0002
wherein the parameters have one of the meanings as given above under formula Ib-1. Thus the invention relates also to a method of production of compounds of formula Ib-1, comprising at least the step of reacting one compound of the followin formula:
Figure imgf000042_0001
with at least one compound of formula R12-MG12-OH, wherein the parameters have one of the meanings as given above under formula Ib- 1. The compounds of formula I and its subformulae can be beneficially utilized in LC media to improve the properties of such media, in particular in LC media for flexoelectric applications. For example, one of the main advantages of using compounds of formula I in LC media for flexoelectric applications is improving the switching speed in the ULH (uniform lying helix) geometry, particularly at
temperatures below 35ºC. Benefits are also observed in terms of the phase range, in terms of an increased isotropic to nematic clearing point and also in terms of a reduced nematic to nematic twist bend transition temperature below room temperature. Therefore, the invention also relates to the use of compounds of formula I in LC media and to a LC media comprising one or more compounds of formula I, as such. In a preferred embodiment, the LC media in accordance with the present invention comprise one or more compounds of formula II, R21-A21-A22-(CH2)a-A23-A24-R22 II wherein
R21 and R22 denote independently H, F, Cl, CN, NCS or a straight- chain or branched alkyl group, which may be
unsubstituted, mono- or polysubstituted by halogen or CN, it being also possible for one or more non-adjacent CH2 groups to be replaced, in each occurrence independently from one another, by -O-, -S-,
-NH-, -N(CH3)-, -CO-, -COO-, -OCO-, -O-CO-O-, -S-CO-, -CO-S-, -CH=CH-, -CH=CF-, -CF=CF- or -C≡C- in such a manner that oxygen atoms are not linked directly to one another,
preferably F, Cl, CN, a straight-chain or branched alkyl or alkoxy group which may be unsubstituted, mono- or polysubstituted by halogen or CN,
more preferably F, CN or OCF3, A21 to A24 denote independently in each occurrence a aryl-,
heteroaryl-, alicyclic- and heterocyclic group,
preferably 1,4-phenylene, wherein in addition one or more CH groups may be replaced by N, trans-1,4- cyclo-hexylene in which, in addition, one or two non- adjacent CH2 groups may be replaced by O and/or S, 1,4-cyclohexenylene, 1,4-bicyclo-(2,2,2)-octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydro- naphthalene-2,6-diyl, 1,2,3,4-tetrahydro-naphthalene- 2,6-diyl, cyclobutane-1,3-diyl, spiro[3.3]heptane-2,6- diyl or dispiro[3.1.3.1] decane-2,8-diyl, it being possible for all these groups to be unsubstituted, mono-, di-, tri- or tetrasubstituted with F, Cl, CN or alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl groups, wherein one or more H atoms may be substituted by F or Cl,
more preferably each independently in each
occurrence 1,4-phenylene, wherein in addition one or more CH groups may be replaced by N or trans-1,4- cyclohexylene in which, in addition, one or two non- adjacent CH2 groups may be replaced by O and/or S, it being possible for both ring groups to be
unsubstituted, mono-, di-, tri- or tetrasubstituted with F, Cl, CN or alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl groups, wherein one or more H atoms may be substituted by F or Cl, a denotes an integer from 1 to 15, preferably an odd (i.e.
uneven) integer and, more preferably 3, 5, 7, 9 or 11. Preferred compounds of formula II are selected from compounds in which the groups (-A21-A22-) and (-A23-A24-) are each and independently selected from the following groups
-Phe-Phe- MG-1 -Phe-Cyc- MG-2 -PheL-PheL- MG-3 -Phe-PheL- MG-4 -PheL-Phe- MG-5 -PheL-Cyc- MG-6 -Cyc-PheL- MG-7 -Cyc-Cyc- MG-8 wherein,
Phe in these groups is 1,4-phenylene,
PheL is a 1,4-phenylene group which is substituted by 1 to 4 groups L, with L being preferably F, Cl, CN, OH, NO2 or an optionally fluorinated alkyl, alkoxy or alkanoyl group with 1 to 7 C atoms, very preferably F, Cl, CN, OH, NO2, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3,
COOC2H5, CF3, OCF3, OCHF2, OC2F5, in particular F, Cl, CN, CH3, C2H5, OCH3, COCH3 and OCF3, most preferably F, Cl, CH3, OCH3 and COCH3 and
Cyc is 1,4-cyclohexylene. Preferred are compounds of formula II wherein the groups (R21-A21-A22-) and (-A23-A24-R22) in formula II are identical or mirror images. Likewise preferred are compounds of formula II wherein (R21-A21-A22-) and (-A23-A24-R22) in formula II are different. Preferred compounds of formula II are indicated below:
Figure imgf000045_0001
Figure imgf000046_0001
wherein
n denotes an integer from 1 to 15, preferably an odd (i.e.
uneven) integer and, more preferably 3, 5, 7, 9 or 11. The compounds of formula II can be synthesized according to or in analogy to methods which are known per se and which are described in standard works of organic chemistry such as, for example, Houben-Weyl, Methoden der organischen Chemie, Thieme-Verlag, Stuttgart. A preferred method of preparation can be taken from WO 2013/004333 A1. In the mixture according to the present invention, the utilization of compounds of formula II beside compounds of formula I, is especially useful in order to further improve the switching speeds whilst maintaining a good phase range and a favorable value for e/K. In a preferred embodiment, the LC media in accordance with the present invention comprise one or more compounds of formula III, R31-A31-A32-(A33)b-Z31-(CH2)c-Z32-A34-A35-A36-R32 III wherein
R31 and R32 have each and independently from another one of the meanings as given for R21 and R22 under formula II, A31 to A36 have each and independently from another one of the meanings as given for A21 to A24 under formula II, Z31 and Z32 are each independently in each occurrence,
-COO-, -OCO-, -O-CO-O-, -OCH2-, -CH2O-, -CH2CH2-, -(CH2)4-, -CF2CF2-, -CH=CH-, -CF=CF-,
-CH=CH-COO-, -OCO-CH=CH- or -C ^C-, optionally substituted with one or more of F, S and/or Si, preferably -COO-, -OCO- or -O-CO-O-,
more preferably -COO- or -OCO-, b denotes an integer from 1 to 15, preferably an odd (i.e.
uneven) integer and, more preferably 3, 5, 7 or 9 and c denotes 0 or 1, preferably 0. Preferred compounds of formula III are selected from compounds in which c denotes 0 and the group (-A31-A32-) is selected from the groups MG-1 to MG-8 as given above. Further preferred compounds of formula III are selected from compounds in which c denotes 1 and the groups (-A24-A25-A26-) and (-A21-A22-A23-) are each and independently selected from the following groups -Cyc-Cyc-Cyc- MG-9
-Phe-Phe-Cyc- MG-10
-Phe-Cyc-Phe- MG-11
-Cyc-Phe-Cyc- MG-12
-Phe-Cyc-Cyc- MG-13
-Phe-Phe-Phe- MG-14 -Phe-Phe-PheL- MG-15
-Phe-PheL-Phe- MG-16
-PheL-Phe-Phe- MG-17
-PheL-Phe-PheL- MG-18
-PheL-PheL-Phe- MG-19
-PheL-PheL-PheL- MG-20
-Phe-PheL-Cyc- MG-21
-Phe-Cyc-PheL- MG-22
-Cyc-Phe-PheL- MG-23
-PheL-Cyc-PheL- MG-24
-PheL-PheL-Cyc- MG-25
-PheL-Cyc-Cyc- MG-26
-Cyc-PheL-Cyc- MG-27 wherein Cyc, Phe, PheL an L have one of the meanings given above for the groups MG-1 to MG-8. Further preferred compounds of formula III are selected from compounds in which c denotes 0 and the group (-A21-A22-) is selected from the groups MG-1 to MG-8 as given above and in which the group (-A24-A25- A26-) is selected from the groups MG-9 to MG-27. Especially preferred compounds of formula III are selected from the rou of com ounds of the followin formulae
Figure imgf000048_0001
Figure imgf000049_0001
The compounds of formula III can be synthesized according to or in analogy to methods which are known per se and which are described in standard works of organic chemistry such as, for example, Houben-Weyl, Methoden der organischen Chemie, Thieme-Verlag, Stuttgart. In the mixture according to the present invention, the utilization of compounds of formula III beside compounds of formula I, is especially useful in order to achieve high stabilities, favourable high clearing points and broad phase ranges, as well as, low appearances of the nematic twist-bend phase. In further preferred embodiment, the LC medium in accordance with the present invention comprises one or more compounds of formula IV, R41-A41-A42-Z41-(CH2)d-Z42-A43-A44-R42 IV wherein
R41 and R42 have each and independently one of the meanings as given above for R21 under formula II, A41 to A44 have each and independently one of the meanings as given above for A21 under formula II, Z41 and Z42 are each independently in each occurrence,
-COO-, -OCO-, -O-CO-O-, -OCH2-, -CH2O-, -CH2CH2-, -(CH2)4-, -CF2CF2-, -CH=CH-, -CF=CF-,
-CH=CH-COO-, -OCO-CH=CH- or -C ^C-, optionally substituted with one or more of F, S and/or Si, preferably -COO-, -OCO- or -O-CO-O-,
more preferably -COO- or -OCO-. d denotes an integer from 1 to 15, preferably an odd (i.e.
uneven) integer and, more preferably 3, 5, 7 or 9. Preferred compounds of formula IV are selected from compounds in which the groups (-A41-A42-) and (-A43-A44-) are each and independently selected from the groups of MG-1 to MG-8 as given above. Especially preferred compounds of formula IV are selected from the group of compounds of the following formulae: - symmetrical ones (IVa and IVb):
Figure imgf000051_0001
Figure imgf000052_0001
Figure imgf000053_0001
- non-symmetrical ones IVc:
Figure imgf000053_0002
Figure imgf000054_0001
The compounds of formula IV are either known or can be synthesized according to or in analogy to methods which are known per se and which are described in standard works of organic chemistry such as, for example, Houben-Weyl, Methoden der organischen Chemie, Thieme- Verlag, Stuttgart. In the mixture according to the present invention, the utilization of compounds of formula IV beside compounds of formula I, is especially useful in order to reduce the nematic twist bend phase whilst maintaining favorable values for e/K. In further preferred embodiment, the LC medium in accordance with the present invention additionally comprises one or more compounds of formula V, R51-A51-Z51-(CH2)e-Z52-A52-(A53)f-R52 V wherein
R51 and R52 have each and independently one of the meanings as given above for R21 under formula II, A51 to A53 have each and independently one of the meanings as given above for A21 under formula II, Z51 and Z52 are each independently in each occurrence,
-COO-, -OCO-, -O-CO-O-, -OCH2-, -CH2O-, -CH2CH2-, -(CH2)4-, -CF2CF2-, -CH=CH-, -CF=CF-,
-CH=CH-COO-, -OCO-CH=CH- or -C ^C-, optionally substituted with one or more of F, S and/or Si, preferably -COO-, -OCO- or -O-CO-O-,
more preferably -COO- or -OCO-, e denotes an integer from 1 to 15, preferably an odd (i.e.
uneven) integer and, more preferably 3, 5, 7 or 9 and f denotes 0 or 1. Especially preferred are compounds of formula V wherein the A51 is selected from the following group of formulae Va’ to Vh’ and the mirror images of formulae Vb’, Ve’ and Vf’
Figure imgf000056_0001
In a preferred embodiment of the present invention are compounds of formula I, wherein A51 and is selected from the group of formulae Va’ to Vc’ or their mirror images. Preferably R51 and R52 in formula V are selected of H, F, Cl, CN, NO2, OCH3, COCH3, COC2H5, COOCH3, COOC2H5, CF3, C2F5, OCF3, OCHF2 and OC2F5, in particular of H, F, Cl, CN, OCH3 and OCF3, especially of H, F, CN and OCF3. Preferred compounds of formula V are selected from the group of compounds of formulae VA to VE, preferably of formulae VA and/or VD, most preferably of formula VD,
Figure imgf000057_0001
wherein LG51 is Z51-(CH2)z-Z52, (F)0 denotes H and
(F)1 denotes F. and the other parameters have the respective meanings given above including the preferred meanings. Preferably Z51-(CH2)z-Z52 denotes -O-CO-(CH2)n-CO-O-, -O-(CH2)n-O- or -(CH2)n -, more preferably -O-CO-(CH2)n-CO-O-, wherein n denotes 3, 5, 7 or 9, Particularly preferred compounds of formula VA are selected from the group of compounds of formulae VA-1 to VA-3
Figure imgf000058_0001
wherein the parameters have the respective meanings given above including the preferred meanings. Particularly preferred compounds of formula VB are selected from the group of compounds of formulae VB-1 to VB-3
Figure imgf000059_0001
F wherein the parameters have the respective meanings given above including the preferred meanings. Particularly preferred compounds of formula VC are selected from the group of compounds of formulae VC-1 and VC-2
Figure imgf000059_0002
wherein the parameters have the respective meanings given above including the preferred meanings. Compounds of formula VD are very much preferred. And of these particularly preferred compounds are selected from the group of compounds of formulae VD-1 to VD-3
Figure imgf000060_0001
wherein the parameters have the respective meanings given above including the preferred meanings. The compounds of formula V can be synthesized according to or in analogy to methods which are known per se and which are described in standard works of organic chemistry such as, for example, Houben- Weyl, Methoden der organischen Chemie, Thieme-Verlag, Stuttgart. A preferred method of preparation is disclosed for example in
WO2015/036079 A1. In a further preferred embodiment, the LC medium in accordance with the present invention additionally comprises one or more compounds of formula VI, R61-A61-A62-(CH2)g-Z61-A63-A64-(A65)h-R62 VI wherein R61 and R62 have each and independently one of the meanings as given above for R21 under formula II, A61 to A64 have each and independently one of the meanings as given above for A21 under formula II, Z61 denotes -O-, -COO-, -OCO-, -O-CO-O-, -OCH2-, -CH2O,
-CH2CH2-, -(CH2)4-, -CF2CF2-, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH- or -C ^C-, optionally substituted with one or more of F, S and/or Si, preferably -O-, -COO-, -OCO- or -O-CO-O-,
more preferably -O-, -COO- or -OCO-, most preferably -COO- or -OCO-, h denotes 0 or 1 and g denotes an integer from 1 to 15, preferably an odd (i.e.
uneven) integer and, more preferably 3, 5, 7 or 9. Preferred compounds of formula VI are selected from compounds in which the groups (-A61-A62-) and (-A63-A64-) are each and independently selected from the groups of MG-1 to MG-8 as given above. Further preferred are compounds of formula VI wherein h denotes 0 and the groups (-A61-A62-) and (-A63-A64-(A65)h) in formula VI are not identical or not mirror images or wherein h denotes 1 In particular preferred compounds of formula VI are selected from the group of compounds of the following formulae,
Figure imgf000061_0001
Figure imgf000062_0001
Figure imgf000063_0001
The compounds of formula VI can be synthesized according to or in analogy to methods which are known per se and which are described in standard works of organic chemistry such as, for example, Houben-Weyl, Methoden der organischen Chemie, Thieme-Verlag, Stuttgart. Preferably, the compounds of formula VI are synthesized according to or in analogy to methods which are disclosed for example in WO 2014/005672 A1. In the mixture according to the present invention, the utilization of compounds of formula VI beside compounds of formula I is especially useful in order to achieve high clearing points and also favorable values for e/K. In a further preferred embodiment, the LC medium in accordance with the present invention additionally comprises one, two, three or more compounds of formula VII, R71-A71-Z71-A72-(Z72-A73)i-(CH2)j-(A74-Z73-)k-A75-Z74-A76-R72 VII wherein
R71 and R72 have each and independently one of the meanings as given above for R21 under formula II, A71 to A76 have each and independently one of the meanings as given above for A21 under formula II, Z71 to Z74 each and independently denotes -COO-, -OCO-,
-O-CO-O-, -OCH2-, -CH2O-, -OCF2-, -CF2O-, -CH2CH2-, -(CH2)4-,-CF2CF2-, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH- or -C ^C-, optionally substituted with one or more of F, S and/or Si or a single bond,
preferably -COO-, -OCO-, -O-CO-O-, -OCF2-, -CF2O- or a single bond
more preferably -COO-, -OCO-, -OCF2-, -CF2O- or a single bond,
with the proviso that at least one of Z71 to Z74 is not a single bond, j denotes an integer from 1 to 15, preferably an odd (i.e.
uneven) integer and, more preferably 3, 5, 7 or 9 and i and k each and independently denotes 0 or 1. Preferred compounds of formula VII are selected from compounds in which at least one of the groups -A71-Z71-A72-(Z72-A73)i-, -(A74-Z73-)k-A75-Z74-A76- are is selected from the groups of MGa to MGn (the two reference Nos.“MG i” and“MG l” being deliberately omitted to avoid any confusion) and their mirror images
Figure imgf000065_0001
Figure imgf000066_0001
wherein wherein L is in each occurrence independently of each other preferably F, Cl, CN or an optionally fluorinated alkyl, alkoxy or alkanoyl group with 1 to 7 C atoms, very preferably F, Cl, CN, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5, in particular F, Cl, CN, CH3, C2H5, OCH3, COCH3 and OCF3, most
preferably F, Cl, CH3, OCH3 and COCH3 and r is in each occurrence independently of each other 0, 1, 2, 3 or 4, preferably 0, 1 or 2.
,
Figure imgf000066_0002
wherein L is preferably F, Cl, CH3, OCH3 and COCH3. Further preferred are compounds of formula VII wherein the groups -A71- Z71-A72-(Z72-A73)i- and -(A74-Z73-)k-A75-Z74-A76- in formula VII are identical or mirror images with the proviso that at least one of Z71 to Z74 is not a single bond. Further preferred are compounds of formula VII, wherein i and k both denote 1, more preferably one of i and k denotes 0 and the other 1, most preferably i and k both denote 0. Especially preferred compounds of formula VII are selected from the group of compounds of the following formulae,
Figure imgf000067_0001
Figure imgf000068_0001
wherein R71 and R72, each and independently denote F or CN. The compounds of formula VII can be synthesized according to or in analogy to methods which are known per se and which are described in standard works of organic chemistry such as, for example, Houben-Weyl, Methoden der organischen Chemie, Thieme-Verlag, Stuttgart. Preferably, the compounds of formula VII are synthesized according to or in analogy to methods which are disclosed for example in WO 2013/174478 A1. In a further preferred embodiment, the medium in accordance with the present invention optionally comprises one or more chiral dopants, especially when utilized in a flexoelectric device. The chiral compounds induce a chiral nematic texture with a pitch (P0), which is in a first approximation inversely proportional to the
concentration (c) of the chiral material used. The constant of
proportionality of this relation is called the helical twisting power (HTP) of the chiral substance and defined by the following equation HTP≡ 1 / (c·P0) (1) wherein
c is concentration of the chiral compound. For example, a uniform lying helix texture is realized using a chiral nematic liquid crystal with a short pitch, typically in the range from 0.2 µm to 1 µm, preferably of 1.0 µm or less, in particular of 0.5 µm or less, which is unidirectional aligned with its helical axis parallel to the substrates, e. g. glass plates, of a liquid crystal cell. In this configuration, the helical axis of the chiral nematic liquid crystal is equivalent to the optical axis of a birefringent plate. Preferred are chiral dopants with a high helical twisting power (HTP), in particular those disclosed in WO 98/00428. Typically, used chiral dopants are e.g. the commercially available
R/S-5011, CD-1, R/S-811 and CB-15 (from Merck KGaA, Darmstadt, Germany). In another preferred embodiment, the chiral dopants are preferably selected from formula VIII,
Figure imgf000070_0001
and/or formula XI,
Figure imgf000070_0002
including the respective (S,S) enantiomer, wherein E and F are each independently 1,4-phenylene or trans-1,4- cyclohexylene, v is 0 or 1, Z0 is -COO-, -OCO-, -CH2CH2- or a single bond and R is alkyl, alkoxy or alkanoyl with 1 to 12 C atoms. The compounds of formula VIII and their synthesis are described in WO 98/00428. The compounds of formula IX and their synthesis are described in GB 2,328,207. The above-mentioned chiral dopants R/S-5011 and the compounds of formula VIII and IX exhibit a very high helical twisting power (HTP) and are therefore particularly useful for the purpose of the present invention. The liquid crystalline medium preferably comprises preferably 1 to 5, in particular 1 to 3, very preferably 1 or 2 chiral dopants, preferably selected from the above formula VIII, and/or formula IX and/or R-5011 or S-5011, very preferably, the chiral compound is R-5011, S- 5011. The amount of chiral compounds in the liquid crystalline medium is preferably from 0.1 to 15 %, in particular from 0.5 to 10 %, very preferably 1 to 5 % by weight of the total mixture. Preferably, the LC medium comprises one or more nematic LC compounds selected from compounds indicated below:
Figure imgf000071_0001
in which
R2A 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-, -CH=CH-, ,
, -O-, -CO-O- or -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, L1 and L2 each, independently of one another, denote F, Cl, CF3 or CHF2, preferably each denote F, Z2 and Z2’ each, independently of one another, denote a single bond, -CH2CH2-, -CH=CH-, -C≡C- , -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F 4-, -CF=CF- or
-CH=CHCH2O-, p denotes 0, 1 or 2, q denotes 0 or 1, (O)CvH2v+1 denotes OCvH2v+1 or CvH2v+1 and v denotes 1 to 6. The liquid crystal media may contain further additives like for example stabilizers, inhibitors, surface-active compounds, lubricating agents, wetting agents, dispersing agents, hydrophobing agents, adhesive agents, flow improvers, defoaming agents, deaerators, diluents, reactive diluents, auxiliaries, colourants, dyes, pigments or nanoparticles in usual concentrations. The total concentration of these further constituents is in the range of 0.1 % to 10 %, preferably 0.1 % to 6 %, based on the total mixture. The concentrations of the individual compounds used each are preferably in the range of 0.1 % to 3 %. The concentration of these and of similar additives is not taken into consideration for the values and ranges of the concentrations of the liquid crystal components and compounds of the liquid crystal media in this application. This also holds for the concentration of the dichroic dyes used in the mixtures, which are not counted when the concentrations of the compounds respectively the components of the host medium are specified. The concentration of the respective additives is always given relative to the final doped mixture. In general, the total concentration of all compounds in the media according to this application is 100 %. The liquid crystal media according to the present invention consists of several compounds, preferably of 2 to 40, more preferably of 3 to 30 and most preferably of 4 to 25 compounds. The media in accordance with the present invention exhibit high values of the elastic constant k11 and a high flexoelectric coefficient e. The liquid crystal media preferably exhibit a k11≤ 100 pN, preferably≤ 20 pN. The liquid crystal media preferably exhibit a k33≤ 100 pN, preferably ≤ 15 pN. The liquid crystal media preferably exhibit a flexoelectric coefficient │e11│≥ 0.2 pC/m, preferably≥ 1 pC/m. The liquid crystal media preferably exhibit a flexoelectric coefficient │e33│≥ 0.2 pC/m, preferably≥ 2 pC/m. The liquid crystal media preferably exhibit a flexo-elastic ratio (ē / K) in the range from 1 to 10 V-1, preferably in the range from 1 to 7 V-1, more preferably in the range from 1 to 5 V-1. The media in accordance with the present invention exhibit high clearing points up to 60°C and higher, preferably up 65°C and higher and more preferably up to 70°C and higher. The media in accordance with the present invention exhibit broad nematic phases of 30°C and more, preferably 35°C and more or even 40°C or more. The media in accordance with the present invention exhibit NTB phases below 20°C or less, preferably below 15°C or less and more preferably below 0°C or less. The media in accordance with the present invention exhibit high stabilities against crystallization at room temperature of more than 100 h, preferably more than 250 h or more than 1000 h. The media in accordance with the present invention exhibit high stabilities against crystallization even at low temperatures (LTS).
Accordingly, the media do not crystallize even at temperatures down to 0°C, preferably down to -10°C, more preferably down to -20°C. In a preferred embodiment, the LC medium comprises: ● 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds of formula I, preferably selected from formulae Ia-1-2a, Ia-1-5a, Ib-1-4a and/or Ib-1-9a. The amount of
compounds of formula I in the liquid crystalline medium as a whole is preferably in the range from 5 to 50 %, in particular in the range from 6 to 30 %, especially in the range from 7 to 20 % by weight of the total mixture, and ● optionally 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds of formula II, preferably selected from compounds compounds of formula II wherein (-A21-A22-) and (-A23-A24-) in formula II are identical or mirror images, more preferably of compounds of formulae II’a-5 and/or II’a-6. The amount of compounds of formula II in the liquid crystalline medium, if present, is preferably in the range from 0 to 30 %, more preferably in the range from 1 to 20 %, even more preferably in the range from 2 to 10 % by weight of the total mixture, and/or ● optionally 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds of formula III, preferably selected from symmetrical compounds of the above formulae IIIc-2 and/or IIIc-3. The amount of compounds of formula III in the liquid crystalline medium, if present, is preferably in the range from 1 to 50 %, more preferably in the range from 5 to 30 %, even more preferably in the range from 10 to 20 % by weight of the total mixture, and/or
● optionally, 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds of formula IV, preferably selected from the symmetrical ones IVb and/or non-symmetrical ones IVc, more preferably from formulae IVb-5, IVc-2, IVc-3, IVc-12 and or IVc-15. The amount of compounds of formula IV in the liquid crystalline medium, if present, is preferably in the range from 1 to 98 %, more preferably in the range from 20 to 80 %, even more preferably in the range from 30 to 60 % by weight of the total mixture, and/or ● optionally, 1 to 6, in particular 2 to 5, very preferably 3 or 4
compounds of formula V, preferably selected from the above formulae VA-1, VD-2 and/or VD-3. The amount of compounds of formula V in the liquid crystalline medium , if present, is preferably in the range from 1 to 70 %, more preferably in the range from 10 to 60 %, even more preferably in the range from 20 to 50 % by weight of the total mixture, and/or ● optionally 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds from the above formulae VI, preferably form compounds of formula VI-4, VI-5, VI-7 and/or VI-9. The amount of compounds of formula VI in the liquid crystalline medium, if present, is preferably from 1 to 40 %, in particular from 5 to 25 %, very preferably 10 to 15 % by weight of the total mixture, and/or ● optionally 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds from the above formulae VII, preferably form compounds of formula VII-4, VII-5 and/or VII-8. The amount of compounds of formula VII in the liquid crystalline medium, if present, is preferably from 1 to 35 %, in particular from 5 to 25 %, very preferably 10 to 15 % by weight of the total mixture,
and/or ● optionally, 1 to 5, in particular 1 to 3, very preferably 1 or 2 chiral dopants, preferably selected from the above formula VIII and/or formula IX and/or R-5011 or S-5011, very preferably, the chiral compound is R-5011 or S-5011. The amount of chiral compounds in the liquid crystalline medium, if present, is preferably from 1 to 15 %, in particular from 0.5 to 10 %, very preferably 0.1 to 5 % by weight of the total mixture, and/or ● optionally up to 25, in particular up to 20, very preferably up to 15, different compounds selected from compounds of formula X. If present, the amount of compounds of formula X in the liquid crystalline medium as a whole, is preferably from 1 to 50 %, in particular from 5 to 30 %, very preferably 10 to 25 % by weight of the total mixture, and/or ● optionally further additives, such as for example stabilizers, antioxidants, etc. in usual concentrations. The total concentration of these further constituents, if present, is in the range of 0.1 to 10 %, preferably 0.1 to 6 %, based on the total mixture. The concentrations of the individual compounds used each are preferably in the range of 0.1 to 3 %. In another preferred embodiment, the LC medium of the present invention consists only of compounds selected from formula I to X, very preferably the LC medium consists only of compounds selected from formula I to IX. The compounds forming the LC medium in accordance with the present invention are mixed in conventional way. As a rule, the required amount of the compound used in the smaller amount is dissolved in the compound used in the greater amount. In case the temperature is above the clearing point of the compound used in the higher concentration, it is particularly easy to observe completion of the process of dissolution. It is, however, also possible to prepare the media by other conventional ways, e.g. using so-called pre-mixtures, which can be e.g. homologous or eutectic media of compounds or using so-called multi-bottle-systems, the constituents of which are ready to use media themselves. Thus, the invention also relates to a process for the production of an LC medium as described above and below. In particular, the invention relates to a process for the production of an LC medium comprising the steps of mixing one or more compounds of formula I, with at least one compound selected from compounds of formulae II to X. The liquid crystalline media in accordance with the present invention can be used in electro optic devices, for example liquid crystal devices, such as STN, TN, AMD-TN, temperature compensation, guest-host, phase change or surface stabilized or polymer stabilized cholesteric texture (SSCT, PSCT) displays, in active and passive optical elements like polarizers, compensators, reflectors, alignment layers, colour filters or holographic elements, in adhesives, synthetic resins with anisotropic mechanical properties, cosmetics, diagnostics, liquid crystal pigments, for decorative and security applications, in nonlinear optics, optical information storage or as chiral dopants. Thus, another aspect of the present invention is the use of a LC medium, comprising at least one compound of formula I in electro optic devices. Since the media in accordance with the present invention are particularly beneficially for flexoelectric liquid crystal display applications, such as, for example, devices of the ULH or USH mode. Thus, another object of the present invention is a liquid crystal device, preferably a flexoelectric device, comprising a medium, which comprises one or more compounds of formula I. A flexoelectric display according to a preferred embodiment of the present invention comprises two plane parallel substrates, preferably glass plates covered with a transparent conductive layer such as indium tin oxide (ITO) on their inner surfaces, optionally alignment layers and a medium comprising one or more compounds of formula I and a chiral dopant as described above and below. If an electrical field is applied to this configuration normal to the helical axis, the optical axis is rotated in the plane of the cell, similar as the director of a ferroelectric liquid crystal rotate as in a surface stabilized ferroelectric liquid crystal display. The field induces a splay bend structure in the director, which is accommodated by a tilt in the optical axis. The angle of the rotation of the axis is in first approximation directly and linearly proportional to the strength of the electrical field. The optical effect is best seen when the liquid crystal cell is placed between crossed polarizers with the optical axis in the unpowered state at an angle of 22.5° to the absorption axis of one of the polarizers. This angle of 22.5° is also the ideal angle of rotation of the electric field, as thus, by the inversion the electrical field, the optical axis is rotated by 45° and by appropriate selection of the relative orientations of the preferred direction of the axis of the helix, the absorption axis of the polarizer and the direction of the electric field, the optical axis can be switched from parallel to one polarizer to the centre angle between both polarizers. The optimum contrast is then achieved when the total angle of the switching of the optical axis is 45°. In that case, the arrangement can be used as a switchable quarter wave plate, provided the optical retardation, i. e. the product of the effective birefringence of the liquid crystal and the cell gap, is selected to be the quarter of the wavelength. In this context, the wavelength referred to is 550 nm, the wavelength for which the sensitivity of the human eye is highest, unless explicitly stated otherwise. The angle of rotation of the optical axis ( ^) is given in good
approximation by the formula: tan ^ = e P0 E / (2 ^ K)
wherein
P0 is the undisturbed pitch of the cholesteric liquid crystal, ē is the average [ē = ½ (e11 + e33)] of the splay flexoelectric
coefficient (e11) and the bend flexoelectric coefficient (e33), E is the electrical field strength and
K is the average [K = ½ (k11 + k33)] of the splay elastic constant (k11) and the bend elastic constant (k33)
and wherein
e / K is called the flexo-elastic ratio. This angle of rotation is half the switching angle in a flexoelectric switching element. The response time
Figure imgf000079_0002
of this electro-optical effect is given in good approximation by the formula:
Figure imgf000079_0001
wherein is the effective viscosity coefficient associated with the distortion of the helix.
Figure imgf000080_0003
The flexoelectric effect is characterized by fast response times (Ton+Toff at 35°C) typically ranging from 1 ms to 10 ms, preferably < 5ms and even more preferably < 3ms. It further features excellent grey scale capability. There is a critical field (Ec) to unwind the helix, which can be obtained from equation
Figure imgf000080_0001
wherein
Figure imgf000080_0002
The inventive media in accordance with the present invention can be aligned in their cholesteric phase into different states of orientation by methods that are known to the expert, such as surface treatment or electric fields. For example, they can be aligned into the planar
(Grandjean) state, into the focal conic state or into the homeotropic state. The term“planar alignment” or orientation of a liquid crystal or
mesogenic material in a display cell or on a substrate means that the mesogenic groups in the liquid crystal or mesogenic material are oriented substantially parallel to the plane of the cell or substrate, respectively. The term“homeotropic alignment” or orientation of a liquid crystal or mesogenic material in a display cell or on a substrate means that the mesogenic groups in the liquid crystal or mesogenic material are oriented substantially perpendicular to the plane of the cell or substrate, respectively. The switching between different states of orientation according to a preferred embodiment of the present invention is exemplarily described below in detail. According to this preferred embodiment, the sample is placed into a cell comprising two plane-parallel glass plates coated with electrode layers, e.g. ITO layers and aligned in its cholesteric phase into a planar state wherein the axis of the cholesteric helix is oriented normal to the cell walls. This state is also known as Grandjean state and the texture of the sample, which is observable e.g. in a polarization microscope, as Grandjean texture. Planar alignment can be achieved e.g. by surface treatment of the cell walls, for example by rubbing and/or coating with an alignment layer such as polyimide. A Grandjean state with a high quality of alignment and only few defects can further be achieved by heating the sample to the isotropic phase, subsequently cooling to the chiral nematic phase at a temperature close to the chiral nematic-isotropic phase transition and flow alignment by lightly pressing the cell. In the planar state, the sample shows selective reflection of incident light, with the central wavelength of reflection depending on the helical pitch and the mean refractive index of the material. When an electric field is applied to the electrodes, for example with a frequency from 10 Hz to 1 kHz and an amplitude of up to 12 Vrms/µm, the sample is being switched into a homeotropic state where the helix is unwound and the molecules are oriented parallel to the field, i.e. normal to the plane of the electrodes. In the homeotropic state, the sample is transmissive when viewed in normal daylight and appears black when being put between crossed polarizers. Upon reduction or removal of the electric field in the homeotropic state, the sample adopts a focal conic texture, where the molecules exhibit a helically twisted structure with the helical axis being oriented
perpendicular to the field, i.e. parallel to the plane of the electrodes. A focal conic state can also be achieved by applying only a weak electric field to a sample in its planar state. In the focal conic state the sample is scattering when viewed in normal daylight and appears bright between crossed polarizers. A sample of a medium in accordance with the present invention in different states of orientation exhibits different transmission of light.
Therefore, the respective state of orientation, as well as its quality of alignment, can be controlled by measuring the light transmission of the sample depending on the strength of the applied electric field. Thereby it is also possible to determine the electric field strength required to
achieve specific states of orientation and transitions between these different states. In a sample of a medium in accordance with the present invention, the above-described focal conic state consists of many disordered
birefringent small domains. By applying an electric field greater than the field for nucleation of the focal conic texture, preferably with additional shearing of the cell, a uniformly aligned texture is achieved where the helical axis is parallel to the plane of the electrodes in large, well-aligned areas. In accordance with the literature on state of the art chiral nematic materials, such as P. Rudquist et al., Liq. Cryst.23 (4), 503 (1997), this texture is also called uniformly lying helix (ULH) texture. This texture is required to characterize the flexoelectric properties of the inventive compound. Starting from the ULH texture, the inventive media can be subjected to flexoelectric switching by application of an electric field. This causes rotation of the optic axis of the material in the plane of the cell substrates, which leads to a change in transmission when placing the material between crossed polarizers. The flexoelectric switching of inventive materials is further described in detail in the introduction above and in the examples. It is also possible to obtain the ULH texture, starting from the focal conic texture, by applying an electric field with a high frequency, of for example 10 kHz, to the sample whilst cooling slowly from the isotropic phase into the cholesteric phase and shearing the cell. The field frequency may differ for different compounds. Apart from the use in flexoelectric devices, the media in accordance with the present invention are also suitable for other types of displays and other optical and electro optical applications, such as optical
compensation or polarizing films, colour filters, reflective cholesterics, optical rotatory power and optical information storage. Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention fully. The following examples are, therefore, to be construed as merely illustrative and not limitative of the remainder of the disclosure in any way whatsoever. Unless the context clearly indicates otherwise, as used herein plural forms of the terms herein are to be construed as including the singular form and vice versa. Throughout the description and claims of this specification, the words “comprise” and“contain” and variations of the words, for example “comprising” and“comprises”, mean“including but not limited to” and are not intended to (and do not) exclude other components. Throughout the present application it is to be understood that the angles of the bonds at a C atom being bound to three adjacent atoms, e.g. in a C=C or C=O double bond or e.g. in a benzene ring, are 120° and that the angles of the bonds at a C atom being bound to two adjacent atoms, e.g. in a C≡C or in a C≡N triple bond or in an allylic position C=C=C are 180°, unless these angles are otherwise restricted, e.g. like being part of small rings, like 3-, 4- or 5-atomic rings, notwithstanding that in some instances in some structural formulae these angles are not represented exactly. It will be appreciated that variations to the foregoing embodiments of the invention can be made while still falling within the scope of the invention. Each feature disclosed in this specification, unless stated otherwise, may be replaced by alternative features serving the same, equivalent or similar purpose. Thus, unless stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. All of the features disclosed in this specification may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. In particular, the preferred features of the invention are applicable to all aspects of the invention and may be used in any combination. Likewise, features described in non-essential combinations may be used separately (not in combination). The parameter ranges indicated in this application all include the limit values including the maximum permissible errors as known by the expert. The different upper and lower limit values indicated for various ranges of properties in combination with one another give rise to additional preferred ranges. The total concentration of all compounds in the media according to this application is 100 %. All concentrations are given in % w/w, unless explicitly stated otherwise. In the foregoing and in the following examples, unless otherwise indicated, all temperatures are set forth uncorrected in degrees Celsius and all parts and percentages are by weight. It goes without saying to the person skilled in the art that the LC media may also comprise compounds in which, for example, H, N, O, Cl, F have been replaced by the corresponding isotopes. The following abbreviations are used to illustrate the liquid crystalline phase behaviour of the compounds: TN,I = clearing point; K = crystalline; N = nematic; NTB = second nematic; S or Sm = smectic; Ch = cholesteric; I = isotropic; Tg = glass transition. The numbers between the symbols indicate the phase transition temperatures in°C. In the present application and especially in the following examples, the structures of the liquid crystal compounds are represented by
abbreviations, which are also called“acronyms”. The transformation of the abbreviations into the corresponding structures is straightforward according to the following three tables A to C. All groups CnH2n+1, CmH2m+1 and CIH2I+I are preferably straight chain alkyl groups with n, m and l C-atoms, respectively, all groups CnH2n, CmH2m and CIH2I are preferably (CH2)n, (CH2)m and (CH2)I, respectively and -CH=CH- preferably is trans- respectively E vinylene. Preferably n, m and l denote an integer between 1 and 12. Table A lists the symbols used for the ring elements, table B those for the linking groups and table C those for the symbols for the left hand and the right hand end groups of the molecules.
Figure imgf000086_0001
Figure imgf000087_0001
Figure imgf000087_0002
Table C: End Groups
Figure imgf000088_0001
wherein n und m each are integers and three points“...” indicate a space for other symbols of this table. Examples A. Compound examples: A.1. Synthesis of BM-1 (7) and BM-2 (8) Step 1.1
Figure imgf000089_0001
Pyridinium chlorochromate (103.6 g, 480 mmol) and 140 g Celite are suspended in 480 ml dichloromethane at room temperature. While stirring, 1,9-nonanediol 1 (35 g, 218 mmol) dissolved in 50 ml tetrahydrofuran and 150 ml dichloromethane is added dropwise between 20 and 30°C. The mixture is filtered, the solvent removed in vacuum and the residue chromatographed on silica gel/dichloromethane; 20 g of crude dialdehyde 2 is obtained and is used in the next step without further purification.
Figure imgf000090_0001
2-Trimethylsilyl-1,3-dithiane 3 (52.8 g, 269 mmol) is dissolved in 190 ml tetrahydrofuran and cooled to -70°C. Butyllithium (107.5 ml of a 2.5 M solution in hexanes, 269 mmol) is slowly added. After the addition is complete, the mixture is warmed to room temperature for 2 hours and then cooled again to -70°C.20 g of dialdehyde 2 in 80 ml tetrahydrofuran is slowly added at that temperature. After the addition is complete, the mixture is warmed to room temperature and worked up as usual. The residue is distilled under reduced pressure and gave 22.9 g of product 4 with a boiling point of 67-74°C at a pressure of 0.1 mbar.
Figure imgf000091_0001
Bis(dithiane) 4 (15.4 mmol) is suspended in 200 ml dichloromethane and cooled to -30°C. Trifluoromethane sulfonic acid (2.98 ml, 34 mmol) is added dropwise while stirring and the mixture is warmed to room temperature for 30 min. It is then cooled again to -70°C, the two phenols 5 (3.1 g, 15.4 mmol) and 6 (3.3 g, 15.4 mmol) together with triethylamine (7.7 ml, 56 mmol) and 70 ml dichloromethane are added dropwise to the mixture. Triethylamine trishydrofluoride (24.9 ml, 154 mmol) is added and subsequently within a period of 60 min bromine (7.9 ml, 154 mmol) in 65 ml dichloromethane. After stirring for one hour at -70°C, the mixture is allowed to warm to -30°C and morpholine (13.5 ml, 154 mmol) is added below -20°C. After warming to 0°C, the mixture is poured onto 200 ml ice water and 19.7 ml aqueous KOH (47 %). The pH is adjusted to approximately 9.0 with additional small amounts of the KOH solution. The organic phase is separated and worked up as usual. After chromatography, of compound 7 (F-PGI-QI-9-Q-PP-N) is isolated.
Figure imgf000091_0002
In addition, the symmetrical difluoroether 8 (N-PP-QI-9-Q-PP-N) is isolated.
Figure imgf000092_0001
1H NMR (500 MHz, Chloroform-d) δ 7.75– 7.69 (m), 7.68– 7.60 (m), 7.59– 7.50 (m), 7.48 (ddt, J = 6.9, 5.3, 1.6 Hz), 7.32– 7.24 (m), 7.17– 7.08 (m), 7.08– 6.99 (m), 2.16 (qt, J = 11.3, 5.8 Hz), 1.66 (ddd, J = 11.9, 6.8, 3.3 Hz), 1.39 (dt, J = 24.3, 6.1 Hz).
Figure imgf000092_0002
1H NMR (500 MHz, Chloroform-d) δ 7.75– 7.69 (m), 7.68– 7.62 (m), 7.58– 7.52 (m), 7.29 (d, J = 8.5 Hz), 3.73 (dtd, J = 14.1, 6.8, 5.4 Hz), 2.23– 2.11 (m), 1.62 (s), 1.46– 1.34 (m), 1.31– 1.21 (m). 2. Synthesis of BM-3 (12)
Step 2.1
Figure imgf000092_0003
Dithiane 4 (18.3 mmol) is suspended in 230 ml dichloromethane, cooled to -30°C and trifluoromethane sulfonic acid (3.5 ml, 40.3 mmol) is added dropwise. The mixture is allowed to warm to room temperature, stirred for 30 min and cooled again to -70°C. A mixture of 4-bromophenol 9 (7 g, 40.3 mmol) and triethylamine (9.1 ml, 65.9 mmol) dissolved in 100 ml dichloromethane is added. After the addition is complete, the mixture is stirred at -70°C for one hour. Triethylamine trishydrofluoride (29.5 ml, 183 mmol) is added and after one hour bromine (9.4 ml, 183 mmol) in 50 ml dichloromethane. Stirring is continued for one hour and the mixture is warmed to -30°C. Morpholine (15.9 ml, 183 mmol) is added below -20°C. Workup is carried out as described above for compound 7 and gave compound 10. Step 2.2
Figure imgf000093_0001
Sodium bicarbonate (1.4 g, 16.8 mmol) is dissolved in 12 ml water;
dibromide 10 (2.4 g, 4.2 mmol) and boronic ester 11 (2.4 g, 8.8 mmol) are dissolved in 20 ml tetrahydrofuran and the two solutions are combined and degassed by bubbling a stream of nitrogen through it. Bis(tri-(tert-butyl)phos-phino)palladium(0) (11 mg, 0.021 mmol) is added and the mixture is heated to reflux for 3 hours. After the usual workup, 2.6 g 12 (N-UIP-QI-9-Q-PU-N) is obtained as a colorless powder.
Figure imgf000093_0002
1H NMR (400 MHz, Chloroform-d) δ 7.46 (d, J = 8.7 Hz), 7.25 (s), 7.21– 7.12 (m), 2.10 (tdd, J = 11.3, 8.0, 5.6 Hz), 1.64– 1.55 (m), 1.39– 1.26 (m). A.3. Synthesis of BM-4 (21) Step 3.1
Figure imgf000094_0001
Sodium metaborate tetrahydrate (45.3 g, 322 mmol) is dissolved in 290 ml water and 300 ml tetrahydrofuran,
bis(triphenylphosphino)palladium(II)chloride (4.6 g, 6 mmol) and hydrazinium hydroxide (0.3 ml, 6 mmol) are added and the mixture is stirred for 5 min at room temperature.1-Bromo-3-fluoro-4-iodobenzene 13 (100 g, 322 mmol), boronic acid ester 14 (81.3 g, 355 mmol) and 330 ml tetrahydrofuran are added and the mixture is heated to reflux overnight. After the usual workup crude 15 is obtained. Step 3.2
Figure imgf000094_0002
15 (126 mmol), bis(triphenylphosphino)palladium(II)chloride (8.4 g, 12 mmol), copper(I)iodide (2.5 g, 13.2 mmol) and diisopropylamine (84.1 ml, 0.6 mol) are combined with 600 ml tetrahydrofuran and warmed to 60°C. Pent-4-in-1-ol 16 (15.2 ml, 151 mmol) is dissolved in 170 ml tetrahydrofuran and is added dropwise within 15 min and the mixture is then heated to reflux overnight. After the usual workup 17 is obtained as a yellow solid. Step 3.3
Figure imgf000095_0001
Crude 17 (31.9 g) is dissolved in 100 ml tetrahydrofuran and
hydrogenated (2.2 kPa H2, 1 h) over platinum on carbon (5 %). Step 3.4
Figure imgf000095_0002
Pyridinium chlorochromate (12.1 g, 56.2 mmol) and Celite (30 g) are suspended in 100 ml dichloromethane and 18 (47 mmol) dissolved in 60 ml dichloromethane is added dropwise between 20 and 30°C. After filtration and the usual workup 19 is obtained as a colorless oil.
Step 3.5
Figure imgf000096_0001
2-Trimethylsilyl-1,3-dithiane (6.7 ml, 35.4 mmol) is dissolved in 40 ml tetrahydrofuran and cooled to -70°C. Butyllithium in hexanes (23.4 ml of a 15 % solution, 37.2 mmol) is added dropwise and the mixture is warmed to -20°C and stirred for 4 hours. It is then cooled again to -70°C and 19 (37.2 mmol) dissolved in 40 ml dichloromethane is added dropwise. After warming to room temperature followed by the usual workup, 20 is obtained as a yellow oil.
Step 3.6
Figure imgf000097_0001
20 (17.2 mmol) is suspended in 200 ml dichloromethane, cooled to -15°C and trifluoromethane sulfonic acid (1.7 ml, 18.9 mmol) is added. The mixture is allowed to warm to room temperature, stirred for 30 min and then cooled to -70°C.4‘-Hydroxy-4-cyano-1,1‘-biphenyl 5 (3.8 g,
18.9 mmol), triethylamine (4.3 ml, 31 mmol) and 100 ml dichloromethane are added dropwise and the mixture is stirred for 1 hour at -70°C.
Triethylamine trishydrofluoride (13.9 ml, 86 mmol) is added dropwise and after 1 hour 4.4 ml (86 mmol) bromine in 100 ml dichloromethane. The mixture is stirred for 1 hour at -70°C. After warming to -20°C, morpholine (7.5 ml, 86 mmol) is added and stirring is continued for 1h at 0°C. After the usual workup 21 (N-PP-QI-5-GP-N) is obtained as a white powder.
Figure imgf000097_0002
( ) 1H NMR (500 MHz, Chloroform-d) δ 7.72 (dd, J = 8.5, 2.4 Hz), 7.65 (d, J = 8.3 Hz), 7.58– 7.52 (m), 7.34 (t, J = 8.0 Hz), 7.28 (d, J = 8.5 Hz), 7.11 – 6.99 (m), 2.70 (t, J = 7.6 Hz), 2.24– 2.12 (m), 1.72 (dtd, J = 12.3, 8.0, 5.9 Hz), 1.53– 1.46 (m). A.4. BM-5, BM-6 and BM-7 In an analogue manner to the synthesis as described under 3. Synthesis of BM-4 (21), the following compounds BM-5, BM-6 and BM-7 are obtained:
C H3
Figure imgf000098_0001
B. Test cells and methods Typically a 3 ^m thick cell, having an anti-parallel rubbed PI alignment layer, is filled on a hotplate at a temperature at which the flexoelectric mixture in the isotropic phase. After the cell has been filled, the phase transitions including clearing point and the crystallization behavior are determined using Differential Scanning Calorimetry (DSC) and verified by optical inspection. For optical phase transition measurements, a Mettler FP90 hot-stage controller connected to a FP82 hot-stage is used to control the temperature of the cell. The temperature is increased from ambient temperature at a rate of 5 degrees C per minute, until the onset of the isotropic phase is observed. The texture change is observed through crossed polarizers using an Olympus BX51 microscope and the respective temperature noted. Wires are then attached to the ITO electrodes of the cell using indium metal. The cell is secured in a Linkam THMS600 hot-stage connected to a Linkam TMS93 hot-stage controller. The hot-stage is secured to a rotation stage in an Olympus BX51 microscope. The cell is heated until the liquid crystal is completely isotropic. The cell is then cooled under an applied electric field until the sample is
completely nematic. The driving waveform is supplied by a Tektronix AFG3021B arbitrary function generator, which is sent through a
Newtons4th LPA400 power amplifier before being applied to the cell. The cell response is monitored with a Thorlabs PDA55 photodiode. Both input waveforms and optical response are measured using a Tektronix TDS 2024B digital oscilloscope. In order to measure the flexoelectric response of the material, the change in the size of the tilt of the optic axis is measured as a function of increasing voltage at a temperature of 35°C, unless stated explicitly otherwise. This is achieved by using the equation:
Figure imgf000099_0001
wherein φ is the tilt in the optic axis from the original position (i.e. when E = 0), E is the applied field, K is the elastic constant (average of K1 and K3) and e is the flexoelectric coefficient (where e = e1 + e3). The applied field is monitored using a HP 34401A multimeter. The tilt angle is measured using the aforementioned microscope and oscilloscope. The undisturbed cholesteric pitch, P0, is measured using an Ocean Optics USB4000 spectrometer attached to a computer. The selective reflection band is obtained and the pitch determined from the spectral data. The media shown in the following examples are well suitable for use in ULH-displays. To that end, an appropriate concentration of the chiral dopant or dopants used has to be applied in order to achieve a typical cholesteric pitch of 350 to 275 nm. C. Mixture examples Host Mixture H-1 The following mixture H1 is prepared.
Figure imgf000100_0001
C.1.1 Mixture example M-1
15 % w/w of the compound BM-1,
Figure imgf000101_0001
are added to 85 % w/w of host mixture H-1. The resulting mixture is homogenized and filled into a test cell as described above. Measurements with respect to the switching performance, the clearing point, the flexo elastic constant and the NTB transition temperature are performed and the results are summarized in the table under C.1.4. C.1.2 Mixture example M-2
15 % w/w of the compound BM-3,
Figure imgf000101_0002
are added to 85 % w/w of host mixture H-1. The resulting mixture is homogenized and filled into a test cell as described above. Measurements with respect to the switching performance, the clearing point, the flexo elastic constant and the NTB transition temperature are performed and the results are summarized in the table under C.1.4. C.1.3 Comparative Mixture Example CM-1 15 % w/w of the compound CM*-1,
Figure imgf000102_0001
are added to 85 % w/w of host mixture H-1. The resulting mixture is homogenized and filled into a test cell as described above. Measurements with respect to the switching
performance, the clearing point, the flexo elastic constant and the NTB transition temperature are performed and the results are summarized in the table under C.1.4 C.1.4 Summary
Figure imgf000102_0002
It is clear from the above given results of the measurement that the materials M-1 and M-2 show an advantage both in terms of phase range and also switching speeds when compared to the material CM-1. At the same time, the flexo elastic constant stays at an acceptable level. In addition, the NTB transition temperature can be favourably lowered by utilizing compounds according to the present invention. Furthermore, it is particularly surprising that the TNI of the mixture M-2 is significantly higher (+8.7°C) than the TNI of the mixture CM-1. C.2.1 Mixture example M-3 15 % w/w of the compound BM-4,
Figure imgf000103_0001
are added to 85 % w/w of host mixture H-1. The resulting mixture is homogenized and filled into a test cell as described above. Measurements with respect to the switching performance, the clearing point, the flexo elastic constant and the NTB transition temperature are performed and the results are summarized in the table under C.2.3. C.2.2 Comparative Mixture Example CM-2 15 % w/w of the compound CM*-2,
Figure imgf000103_0002
are added to 85 % w/w of host mixture H-1. The resulting mixture is homogenized and filled into a test cell as described above. Measurements with respect to the switching performance, the clearing point, the flexo elastic constant and the NTB transition temperature are performed and he results are summarized in the table under C.2.3. C.2.3 Summary
Figure imgf000104_0001
From the results of the measurement, it is clear that the material containing BM-4 in accordance with the present has a significant advantage with respect to the switching speed when compared to material comprising a compound of the prior art (CM*-2). The TNI is also similar, something that is surprising when considering conventional liquid crystal materials with differing switching speeds when normally a strong inverse relationship between TNI and switching speeds is observed (i.e. higher TNI leads to reduced switching speeds).
C.3.1 Mixture example M-4 15 % w/w of the compound BM-4,
Figure imgf000105_0001
are added to 85 % w/w of host mixture H-1. The resulting mixture is homogenized and filled into a test cell as described above. Measurements with respect to the switching performance, the clearing point, the flexo elastic constant and the NTB transition temperature are performed and the results are summarized in the table under C.3.3 C.3.2 Comparative Mixture Example CM-3 15 % w/w of the compound CM*-3,
Figure imgf000105_0002
are added to 85 % w/w of host mixture H-1. The resulting mixture is homogenized and filled into a test cell as described above.
Measurements with respect to the switching performance, the clearing point, the flexo elastic constant and the NTB transition temperature are performed and the results are summarized in the table under C.3.3 C.3.3 Summary
Figure imgf000106_0001
From the results of the measurement, it is clear that the material containing BM-6 in accordance with the present has a significant advantage with respect to the switching speed when compared to material comprising a compound of the prior art (CM*-3). The TNI is also similar, something that is surprising when considering conventional liquid crystal materials with differing switching speeds when normally a strong inverse relationship between TNI and switching speeds is observed (i.e. higher TNI leads to reduced switching speeds).
C.4.1 Mixture example M-5 15 % w/w of the compound BM-7,
Figure imgf000107_0001
are added to 85 % w/w of host mixture H-1. The resulting mixture is homogenized and filled into a test cell as described above.
Measurements with respect to the switching performance, the clearing point, the flexo elastic constant and the NTB transition temperature are performed and the results are summarized in the table under C.4.3 C.4.2 Comparative Mixture Example CM-4 15 % w/w of the compound CM*-4,
Figure imgf000107_0002
are added to 85 % w/w of host mixture H-1. The resulting mixture is homogenized and filled into a test cell as described above.
Measurements with respect to the switching performance, the clearing point, the flexo elastic constant and the NTB transition temperature are performed and the results are summarized in the table under C.4.3 C.4.3 Summary
Figure imgf000108_0001
From the results of the measurement, it is clear that the material containing BM-7 in accordance with the present has a significant advantage with respect to the switching speed and the TNI when compared to material comprising a compound of the prior art (CM*-4).
C.5.1 Comparative Mixture Example CM-5
The following comparative mixture example is prepared CM-5
Figure imgf000109_0002
The mixture is homogenized and filled into a test cell. Measurements with respect to the switching performance, the clearing point, the flexo elastic constant and the NTB transition temperature are performed . The results are summarized in the table under C.5.3. C.5.1 Mixture Example M-6
The following mixture example is prepared CM-6
Figure imgf000109_0001
The mixture is homogenized and filled into a test cell. Measurements with respect to the switching performance, the clearing point, the flexo elastic constant and the NTB transition temperature are performed. The results are summarized in the table under C.5.3
C.5.3 Summary
Figure imgf000110_0001
It can be clearly seen from the data in the table that the addition of the compound BM-7 results in over a 20 % improvement in the switching speed. This is a considerable advantage for ULH mixtures, especially for applications such as field sequential colour driving. Only a small reduction in TNI and e/K are observed due to the addition of BM-7, which means that the overall benefit to the performance is still significant.

Claims

Patent Claims 1. Compound of formula I, R11-MG11-X11-Sp11-X12-MG12-R12 I wherein
R11 and R22 are each independently H, F, Cl, CN, NCS or a straight-chain or branched alkyl group, which may be unsubstituted, mono- or polysubstituted by halogen or CN, it being also possible for one or more non-adjacent CH2 groups to be replaced, in each occurrence independently from one another, by -O-, -S-, -NH-, -N(CH3)-, -CO-, -COO-, -OCO-, -O-CO-O-, -S-CO-, -CO-S-, -CH=CH-, -CH=CF-, -CF=CF- or -C≡C- in such a manner that oxygen atoms are not linked directly to one another, MG11 and MG12 are each independently a mesogenic group, Sp11 is a spacer group comprising 1, 3 or 5 to 40 C
atoms, wherein one or more non-adjacent and non- terminal CH2 groups may also be replaced by -O-, -S-, -NH-, -N(CH3)-, -CO-, -O-CO-, -S-CO-,
-O-COO-, -CO-S-, -CO-O-, -CF2-, -CF2O-, -OCF2-, -C(OH)-, -CH(R11)-, -CH=CH- or -C ^C-, however in such a way that no two O-atoms are adjacent to one another and no two groups selected from -O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O- and -CH=CH- are adjacent to each other, X11 and X12 denote -CF2-O-, -O-CF2- or a single bond, whereby at least one of X11 or X12 denotes -CF2-O-, or -O-CF2-.
2. Compound according to claim 1 characterized in that it is selected from the group of compounds of formulae Ia-1 or Ib-1 R11-MG11-OCF2-(CH2)n-CF2O-MG12-R12 Ia-1 R11-MG11-(CH2)n-CF2O-MG12-R12 Ib-1 wherein R11, R22, MG11, MG12 have one of the meanings as given above in claim 1 and n denotes 1, 3 or an integer from 5 to 15.
3. Method of production of compounds of formula Ia-1, comprising at least the ste of reactin one compound of the following formula,
Figure imgf000112_0001
with one or more compounds of formulae R11-MG11-OH or
R12-MG12-OH, wherein the parameters have one of the meanings as given above in claim 2.
4. Method of production of compounds of formula Ib-1, comprising at least the step of reacting one compound of the formula:
Figure imgf000112_0002
with at least one compound of formula R12-MG12-OH,
wherein the parameters have one of the meanings as given above in claim 2.
5. Use of the compounds of formula I in a liquid crystalline medium.
6. LC medium comprising one or more compounds of formula I.
7. LC medium according to claim 6, comprising one or more
compounds of formula II, R21-A21-A22-(CH2)a-A23-A24-R22 II wherein
R21 and R22 denote each and independently H, F, Cl, CN, NCS or a straight-chain or branched alkyl group, which may be unsubstituted, mono- or polysubstituted by halogen or CN, it being also possible for one or more non- adjacent CH2 groups to be replaced, in each
occurrence independently from one another, by -O-, -S-, -NH-, -N(CH3)-, -CO-, -COO-, -OCO-, -O-CO-O-, -S-CO-, -CO-S-, -CH=CH-, -CH=CF-, -CF=CF- or -C≡C- in such a manner that oxygen atoms are not linked directly to one another, A21 to A24 denote each and independently in each occurrence a aryl-, heteroaryl-, alicyclic- and heterocyclic group and a denotes an integer from 1 to 15.
8. LC medium according to claim 6 or 7, comprising one or more
compounds of formula III, R31-A31-A32-(A33)b-Z31-(CH2)c-Z32-A34-A35-A36-R32 III wherein
R31 and R32 have each and independently from another one of the meanings as given for R21 under formula II, A31 to A36 have each and independently from another one of the meanings as given for A21 under formula II, Z31 and Z32 denote each and independently in each occurrence, -COO-, -OCO-, -O-CO-O-, -OCH2-, -CH2O-,
-CH2CH2-, -(CH2)4-, -CF2CF2-, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH- or -C ^C-, optionally substituted with one or more of F, S and/or Si c denotes an integer from 1 to 15 and
a denotes 0 or 1.
9. LC medium according to one or more of claims 6 to 8, comprising one or more compounds of formula IV, R41-A41-A42-Z41-(CH2)d-Z42-A43-A44-R42 IV wherein
R41 and R42 have each and independently from another one of the meanings as given for R21 under formula II,
A41 to A44 have each and independently from another one of the meanings as given for A21 under formula II, Z41 and Z42 are each independently in each occurrence,
-COO-, -OCO-, -O-CO-O-, -OCH2-, -CH2O-,
-CH2CH2-, -(CH2)4-, -CF2CF2-, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH- or -C ^C-, optionally substituted with one or more of F, S and/or Si, d denotes an integer from 1 to 15,
10. LC medium according to one or more of claims 6 to 9, comprising one or more compounds of formula V, R51-A51-Z51-(CH2)e-Z52-A52-(A53)f-R52 V wherein
R51 and R52 have each and independently from another one of the meanings as given for R21 under formula II, A51 to A53 have each and independently from another one of the meanings as given for A21 under formula II, Z51 and Z52 are each independently in each occurrence,
-COO-, -OCO-, -O-CO-O-, -OCH2-, -CH2O-, -CH2CH2-, -(CH2)4-, -CF2CF2-, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH- or -C ^C-, optionally substituted with one or more of F, S and/or Si, f denotes 0 or 1, e denotes an integer from 1 to 15,
11. LC medium according to one or more of claims 6 to 10, comprising one or more compounds of formula VI, R61-A61-A62-(CH2)g-Z61-A63-A64-(A65)h-R62 VI wherein
R61 and R62 have each and independently from another one of the meanings as given for R21 and R22 under formula II, A61 to A64 have each and independently one of the meanings as given above for A21 under formula II, Z61 denotes -O-, -COO-, -OCO-, -O-CO-O-, -OCH2-,
-CH2O, -CH2CH2-, -(CH2)4-, -CF2CF2-, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH- or -C ^C-, optionally substituted with one or more of F, S and/or Si, h denotes 0 or 1 and g denotes an integer from 1 to 15.
12. LC medium according to one or more of claims 6 to 11, comprising one or more compounds of formula VII, R71-A71-Z71-A72-(Z72-A73)j-(CH2)k-(A74-Z73-)l-A75-Z74-A76-R72 VII wherein
R71 and R72 have each and independently one of the meanings as given above for R21 under formula II, A71 to A76 have each and independently one of the meanings as given above for A21 under formula II, Z71 to Z74 each and independently denotes -COO-, -OCO-,
-O-CO-O-, -OCH2-, -CH2O-, -OCF2-, -CF2O-, -CH2CH2-, -(CH2)4-,-CF2CF2-, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH- or -C ^C-, optionally substituted with one or more of F, S and/or Si or a single bond, with the proviso that at least one of Z71 to Z74 is not a single bond, j denotes an integer from 1 to 15 and i and k denotes 0 or 1.
13. LC medium according to one or more of claims 6 to 12, comprising one or more chiral dopants.
14. LC medium according to one or more of claims 6 to 13, comprising one or more nematic LC compounds selected compounds selected from compounds of formula X-1 to X-4,
Figure imgf000117_0001
in which
R2A denotes H, an alkyl, alkenyl 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-, -CH=CH-, , , -O- , -CO-O- or -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, L1 and L2 each, independently of one another, denote F, Cl,
CF3 or CHF2, preferably each denote F, Z2 and Z2’ each, independently of one another, denote a sin- gle bond, -CH2CH2-, -CH=CH-, -C≡C- , -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF- or -CH=CHCH2O-, p denotes 0, 1 or 2, q denotes 0 or 1, (O)CvH2v+1 denotes OCvH2v+1 or CvH2v+1 and v denotes 1 to 6.
15. Method for the production of an LC medium according to one or more of claims 6 to 14, comprising the step of mixing one or more compounds of formula I, with at least one compound selected from compounds of formulae II to X.
16. Use of a LC medium according to one or more of claims 6 to 14, in electro optic devices.
17. Electro optical device comprising a medium according to one or more of claims 6 to 14.
18. Electro optical device according to claim 17, characterized in that it is a flexoelectric device.
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