Aromatic isothiocyanates

Abstract

The present invention relates to a compound of the formula G as defined in claim 1, to liquid crystal media comprising the compound of the formula G and to high-frequency components comprising these media, in particular microwave components for high-frequency devices, such as microwave phase shifting devices, tunable filters, tunable metamaterial structures and electronic beam steering antennas, such as phased array antennas.

Description

[0001] The present invention relates to aromatic isothiocyanates, liquid crystal media containing the same and to high-frequency components containing these media, in particular microwave components for high-frequency devices such as microwave phase shifting devices, tunable filters, tunable metamaterial structures and electronic beam steering antennas (e.g. phased array antennas), and to devices containing the components.

[0002] Liquid-crystalline media have been used for many years in electro-optical displays (liquid crystal displays: LCD) for displaying information. However, more recently, liquid-crystalline media have also been proposed for use in components for microwave technology, such as in DE 10 2004 029 429 and JP 2005-120208 (A).

[0003] A. Gaebler, F. Goelden, S. Müller, A. Penirschke and R. Jakoby, "Direct Simulation of Material Permittivites using an Eigen-Susceptibility Formulation of the Vector Variational Approach", 12 MTC 2009-International Instrumentation and Measurement Technology Conference, Singapore, 2009 (IEEE), pp. 463-467 describe the corresponding properties of the known liquid crystal mixture E7 (Merck KGaA, Germany).

[0004] DE 10 2004 029 429 A describes the use of liquid-crystalline media in microwave technology, in particular in phase shifters. The properties of liquid-crystalline media in the corresponding frequency range are discussed therein, and liquid-crystalline media based on mixtures of predominantly aromatic nitriles and isothiocyanates are demonstrated.

[0005] In EP 2 982 730 A1, mixtures consisting entirely of isothiocyanate compounds are described, wherein compounds containing up to two fluorine atoms in the immediate vicinity of the isothiocyanate group are proposed and exemplified. Fluorine atoms are frequently used in mesogenic compounds to introduce polarity. In particular in combination with terminal NCS groups, high dielectric anisotropy values ​​can be achieved, especially when the NCS group in the 1-position has two fluorine atoms in its ortho-position, since the overall molecular dipole is the sum of all individual dipoles of the molecular partial structures.

[0006] On the other hand, since fluorine substitution generally has a negative effect on the nematic properties of the compounds, a well-balanced compromise with regard to the number of fluorine atoms must be found. In the case of bulky substituents, such as alkyl groups, the negative effect can be more pronounced. Such compounds are hardly known in the prior art in connection with liquid crystal display applications, since they generally exhibit high viscosities and low clearing temperatures.

[0007] Compositions that can be used in microwave applications still have several disadvantages. There is a need to improve the general physical properties, shelf life and stability of these media when operated in devices. In view of the many different parameters that must be considered and improved in order to develop liquid crystal media for microwave applications, it is desirable to have a wider range of possible mixture components for developing such liquid crystal media.

[0008] It was an object of the present invention to provide compounds for use in liquid-crystalline media having improved properties in connection with applications in the microwave range of the electromagnetic spectrum.

[0009] This object is achieved according to the invention by compounds of the general formula G,

[0010]

[0011] in

[0012] R G represents H; fluorinated or non-fluorinated, preferably non-fluorinated, straight-chain or branched alkyl having 1 to 12 C atoms; or fluorinated or non-fluorinated, preferably non-fluorinated, straight-chain or branched alkenyl having 2 to 12 C atoms, wherein one or more CH2- groups may be substituted, and one or more non-adjacent CH2-groups may be replaced by -O-,

[0013] Z G1 , Z G2 represent, identically or differently, -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C≡C-, -C≡CC≡C- or a single bond, preferably -CF=CF-, -C≡C- or a single bond,

[0014] X represents Cl or F, preferably F,

[0015] R represents a straight-chain, branched or cyclic alkyl radical having 1 to 6 C atoms, preferably methyl, ethyl, isopropyl or cyclopropyl, very preferably methyl;

[0016] t is 0, 1 or 2, preferably 0 or 1, and

[0017] and represents a radical selected from the group consisting of a) 1,4-phenylene, 1,4-naphthylene and 2,6-naphthylene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L,

[0018] b) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydronaphthalene-2,6-diyl, tetrahydronaphthalene-5,8-diyl, decahydronaphthalene-2,6-diyl, bicyclo[1.1.1]pentane-1,3-diyl, 4,4′-bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl and spiro[3.3]heptane-2,6-diyl, in which one or two CH groups may be replaced by N, one or more non-adjacent CH2 groups may be replaced by -O- and / or -S-, and in which one or more H atoms may be replaced by L,

[0019] c) the group consisting of thiophene-2,5-diyl, thieno[3,2-b]thiophene-2,5-diyl, selenophene-2,5-diyl, each of which may also be mono- or poly-substituted by L,

[0020] L, identically or differently on each occurrence, represents F, Cl, CN, SCN, SF5 or linear or branched, in each case optionally fluorinated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, each having 1 to 12 C atoms.

[0021] According to another aspect of the present invention, a liquid crystal medium is provided which comprises one or more compounds of formula G.

[0022] Preferred embodiments of the invention are the subject matter of the dependent claims or can also be taken from the description.

[0023] Surprisingly, it has been found that it is possible to achieve liquid-crystalline media having excellent stability and at the same time high dielectric anisotropy, reasonably fast switching times, a suitable nematic phase range, high tunability and low dielectric losses in the microwave range of the electromagnetic spectrum by using compounds of the formula G in liquid-crystalline media.

[0024] In particular, the compounds according to the invention enable media with a high tunability τ and exhibit excellent miscibility with liquid crystal hosts, in particular those containing similar polar compounds of the isothiocyanate type. Since these polar compounds generally have limited solubility in the host material, it is possible to increase the overall proportion of compounds with high tunability in the medium and thus achieve good tunability of the medium for microwave applications by adding compounds of formula G.

[0025] The media according to the invention are characterized by a high brightness temperature, a broad nematic phase range and excellent low temperature stability (LTS). Thus, devices containing the media can be operated under extreme temperature conditions.

[0026] The medium is further characterized by a high dielectric anisotropy value and a low rotational viscosity. Therefore, the threshold voltage, i.e. the minimum voltage at which the device can switch, is very low. Low operating voltage and low threshold voltage are required in order to enable the device to have improved switching characteristics and high energy efficiency. Low rotational viscosity enables fast switching of the device according to the invention.

[0027] These properties overall make the medium particularly suitable for components and devices in high-frequency technology and for applications in the microwave range, in particular microwave phase shifting devices, tunable filters, tunable metamaterial structures and electronic beam steering antennas (eg phased array antennas).

[0028] Thus, according to another aspect of the invention, there is provided a component and a device comprising the component, both of which are operable in the microwave region of the electromagnetic spectrum. Preferred components are phase shifters, varactor diodes, wireless and radio wave antenna arrays, matching circuits and adaptable filters.

[0029] In this context, “high-frequency technology” means the use of electromagnetic radiation with a frequency in the range of 1 MHz to 1 THz, preferably 1 GHz to 500 GHz, more preferably 2 GHz to 300 GHz, particularly preferably about 5 GHz to 150 GHz.

[0030] As used herein, halogen is F, Cl, Br or I, preferably F or Cl, and particularly preferably F.

[0031] In this context, alkyl is linear or branched or cyclic and has 1 to 12 C atoms, preferably linear and, unless otherwise indicated, has 1, 2, 3, 4, 5, 6 or 7 C atoms, and is therefore preferably methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl or n-heptyl.

[0032] In this context, the branched alkyl group is preferably isopropyl, sec-butyl, isobutyl, 2-methylbutyl, isopentyl (3-methylbutyl), 2-methylhexyl or 2-ethylhexyl.

[0033] As used herein, cycloalkyl means a straight-chain or branched alkyl or alkenyl radical having up to 12 C atoms, preferably an alkyl radical having 1 to 7 C atoms, wherein the radical CH2 is replaced by a carbocyclic ring having 3 to 5 C atoms, very preferably selected from the group consisting of cyclopropylalkyl, cyclobutylalkyl, cyclopentylalkyl and cyclopentenylalkyl.

[0034] Herein, alkoxy is straight-chain or branched and contains 1 to 12 C atoms. Alkoxy is preferably straight-chain and, unless otherwise indicated, has 1, 2, 3, 4, 5, 6 or 7 C atoms and is therefore preferably methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, n-hexoxy or n-heptoxy.

[0035] Herein, alkenyl is preferably an alkenyl with 2 to 12 C atoms, the alkenyl being straight or branched, and containing at least one C-C double bond. The alkenyl is preferably straight chain, and has 2 to 7 C atoms. Therefore, the alkenyl is preferably vinyl, prop-1-enyl or prop-2-enyl, but-1-enyl, but-2-enyl or but-3-enyl, pent-1-enyl, pent-2-enyl, pent-3-enyl or pent-4-enyl, hex-1-enyl, hex-2-enyl, hex-3-enyl, hex-4-enyl or hex-5-enyl, hept-1-enyl, hept-2-enyl, hept-3-enyl, hept-4-enyl, hept-5-enyl or hept-6-enyl. If two C atoms of the C-C double bond are substituted, the alkenyl may be in the form of E and / or Z isomers (trans / cis). Generally speaking, the corresponding E isomer is preferred. Among the alkenyl groups, prop-2-enyl, but-2-enyl and but-3-enyl and also pent-3-enyl and pent-4-enyl are particularly preferred.

[0036] Herein, alkynyl is understood to mean an alkynyl radical having 2 to 12 C atoms, which is straight-chain or branched and contains at least one C—C triple bond. 1-Propynyl and 2-propynyl as well as 1-, 2- and 3-butynyl are preferred.

[0037] The fluorinated alkyl-, alkoxy-, alkenyl or alkenyloxy radicals may be branched or unbranched and partially fluorinated, preferably perfluorinated. In the case of alkenyl with 2, 3, 4, 5, 6 or 7 C atoms, they are preferably unbranched and have 1, 2, 3, 4, 5, 6 or 7 C atoms, which are very preferably selected from -(CH2) n -CH=CF2、-(CH2) n -CH=CHF, -(CH2) n -CH=Cl2、-C n F 2n+1 、-(CF2) n -CF2H, -(CH2) n -CF3, -(CH2) n -CHF2, -(CH2) n CH2F, -CH=CF2, -O(CH2) n -CH=CF2、-OC n F 2n+1 、-O(CF2) n -CF2H, -O(CH2)n CF3, -O(CH2) n -CHF2, -O(CF) n CH2F, -OCF=CF2, wherein n is an integer from 0 to 7; in particular OCF3.

[0038] The compounds of the general formula G are prepared as described in the literature, for example in standard works such as Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart, by methods known per se, specifically under reaction conditions known and suitable for the reaction. Variants known per se but not mentioned in greater detail here can be used.

[0039] If desired, the starting materials can also be formed in situ without isolating them from the reaction mixture, but rather by reacting them immediately further to form the compound of the general formula G.

[0040] Compounds of formula G can be prepared analogously to the methods described in EP 1 054 001 A1. Preferred synthetic routes for the compounds according to the invention are illustrated in the following Scheme 1, in which the radicals and parameters occurring have the meanings given for formula G. They are further illustrated with the aid of working examples and can be adapted to the specific desired compounds of general formula G by selecting suitable starting materials.

[0041] Preferred building blocks 2 (Scheme 1) are, for example, 4-bromo-2-chloro-6-methyl-aniline, 4-bromo-2-fluoro-6-methyl-aniline, 4-bromo-2-chloro-6-ethyl-aniline or 4-bromo-2-ethyl-6-fluoro-aniline, all described in the literature, which can be reacted, for example, by a cross-coupling reaction generally known as the Sonogashira reaction (Scheme 1, where Z G1 -C≡C- and G is H), Suzuki coupling (where Z G1 is a single bond, -CH=CH-, -CF=CF-, -CH=CF- or -CF=CH-, and G is a boronic acid or alkyl borate group) and related transition metal-catalyzed cross-coupling reactions, reacting with a suitable intermediate 1 to obtain a compound of formula G.

[0042] The compound of formula N is reacted with a thiocarbonic acid derivative Reaction, wherein X and Y are leaving groups, or reaction with CS2 to obtain a compound of formula G.

[0043] Scenario 1:

[0044]

[0045] Preferred reagents for the process according to the invention for converting the compound of formula N into the compound of formula G are carbon disulfide, thiophosgene, thiocarbonyldiimidazole, di-2-pyridylthiocarbonate, bis(dimethyl thiocarbamoyl)disulfide, dimethylaminothiocarbonyl chloride and phenylchlorothioformate, very preferably thiophosgene.

[0046] The reactions described should be regarded as illustrative only. A person skilled in the art can carry out corresponding variations of the syntheses described and also follow other suitable synthetic routes in order to obtain compounds of formula G.

[0047] The compound of formula G is preferably selected from the group consisting of compounds of formulae G-1 to G-6,

[0048]

[0049] Where R G , Z G1 , Z G2 , and has the meaning given above for formula G, and preferably Z G1 , Z G2 The same or different refers to -CF=CF- or -C≡C-.

[0050] R G represents a straight-chain or branched or cyclic alkyl or alkenyl group having 1 to 7 C atoms, and and Preferably the same or different

[0051]

[0052] Where R L Each occurrence may be the same or different and may have 1 to 6

[0053] C atoms in alkyl groups,

[0054] Or

[0055] One or more H atoms may be ligated to the radical R L or F, and where

[0056] R L represents H or an alkyl group having 1 to 6 C atoms;

[0057] Very preferably express as well as express In particular

[0058] Very preferred compounds of formula G are selected from the following sub-formulae:

[0059]

[0060]

[0061]

[0062] Where R G has the meanings given above and preferably denotes straight-chain or branched alkyl having 1 to 7 C atoms, in particular methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl or n-heptyl.

[0063] According to another aspect of the present invention, there is provided a liquid crystal medium comprising one or more compounds of formula G. Preferably, the medium comprises one or more compounds selected from the group consisting of formulae I, II and III:

[0064]

[0065] in

[0066] R 1 represents H; non-fluorinated alkyl or non-fluorinated alkoxy having 1 to 17, preferably 2 to 10 C atoms; or non-fluorinated alkenyl, non-fluorinated alkenyloxy or non-fluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10 C atoms, wherein one or more CH2- groups may be Instead,

[0067] Preferably, it is a non-fluorinated alkyl group or a non-fluorinated alkenyl group,

[0068] n is 0, 1, or 2,

[0069] to

[0070] In each occurrence, they are expressed independently of each other

[0071]

[0072] Where R L represents, identically or differently on each occurrence, H or alkyl having 1 to 6 C atoms, preferably H, methyl or ethyl, particularly preferably H,

[0073] or

[0074] One or more H atoms may be ligated to the radical RL or F

[0075] Instead,

[0076] And among them Alternatively,

[0077]

[0078] Best

[0079]

[0080] And when n=2, Preferred representation and the other preferably represents

[0081]

[0082] Preferably

[0083] to

[0084] Independently express

[0085]

[0086] More preferably

[0087] express

[0088] express

[0089] express

[0090] R 2 represents H; non-fluorinated alkyl or non-fluorinated alkoxy having 1 to 17, preferably 2 to 10 C atoms; or non-fluorinated alkenyl, non-fluorinated alkenyloxy or non-fluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10 C atoms, wherein one or more CH2- groups may be Instead, preferably a non-fluorinated alkyl or non-fluorinated alkenyl group,

[0091] Z 21 represents trans-CH=CH-, trans-CF=CF- or -C≡C-, preferably -C≡C- or trans-CH=CH-,

[0092] and

[0093] Independently express

[0094]

[0095] Where R L represents, identically or differently on each occurrence, H or alkyl having 1 to 6 C atoms, preferably H, methyl or ethyl, particularly preferably H,

[0096] or

[0097] One or more H atoms may be ligated to the radical R L Or F instead,

[0098] Preferably

[0099] and

[0100] Independently express

[0101]

[0102]

[0103] Preferably means

[0104] and

[0105]

[0106] Preferably means

[0107]

[0108] More preferably

[0109]

[0110] R 3 represents H; non-fluorinated alkyl or non-fluorinated alkoxy having 1 to 17, preferably 2 to 10 C atoms; or non-fluorinated alkenyl, non-fluorinated alkenyloxy or non-fluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10 C atoms, wherein one or more CH2- groups may be Instead,

[0111] Preferably, it is a non-fluorinated alkyl group or a non-fluorinated alkenyl group,

[0112] Z 31 and Z 32 One of the following, preferably Z 32; represents trans-CH=CH-, trans-CF=CF- or -C≡C-, and the other of them independently represents -C≡C-, trans-CH=CH-, trans-CF=CF- or a single bond, preferably one of them, preferably Z 32 represents -C≡C- or trans-CH=CH-, and the other represents a single bond, and

[0113]

[0114] to

[0115] Independently express

[0116]

[0117] Where R L represents, identically or differently on each occurrence, H or alkyl having 1 to 6 C atoms, preferably H, methyl or ethyl, particularly preferably H,

[0118] or

[0119] One or more H atoms may be ligated to the radical R L Or F instead,

[0120] And among them

[0121] Alternatively,

[0122] Preferably

[0123] to

[0124] Independently express

[0125]

[0126]

[0127] More preferably

[0128] express

[0129]

[0130] express

[0131] in particular

[0132] express

[0133] in particular

[0134] In the compounds of formula I, formula II and formula III, R L Preferably it represents H.

[0135] In another preferred embodiment, in the compounds of formula I, II and III, one or two radicals R L , preferably a group R L Different from H.

[0136] In a preferred embodiment of the present invention, the compound of formula I is selected from the group consisting of compounds of formula I-1 to formula I-5:

[0137]

[0138] in

[0139] L 1 , L 2 and L 3 represents H or F in the same or different manner on each occurrence,

[0140] and the other groups have the corresponding meanings indicated above for formula I, and

[0141] Preferably R 1 represents a non-fluorinated alkyl group having 1 to 7 C atoms or a non-fluorinated alkenyl group having 2 to 7 C atoms.

[0142] The medium preferably comprises one or more compounds of the formula I-1, which are preferably selected from the group of compounds of the formulae I-1a to I-1d, preferably compounds of the formula I-1b:

[0143]

[0144]

[0145] Where R 1 R has the meaning indicated above for formula I and preferably denotes non-fluorinated alkyl having 1 to 7 C atoms or non-fluorinated alkenyl having 2 to 7 C atoms.

[0146] The medium preferably comprises one or more compounds of the formula I-2, which are preferably selected from the group of compounds of the formulae I-2a to I-2e, preferably compounds of the formula I-2c:

[0147]

[0148] Where R 1R has the meaning indicated above for formula I and preferably denotes non-fluorinated alkyl having 1 to 7 C atoms or non-fluorinated alkenyl having 2 to 7 C atoms.

[0149] The medium preferably comprises one or more compounds of the formula I-3, which are preferably selected from the group of compounds of the formulae I-3a to I-3d, particularly preferably compounds of the formula I-3b:

[0150]

[0151] Where R 1 R has the meaning indicated above for formula I and preferably denotes non-fluorinated alkyl having 1 to 7 C atoms or non-fluorinated alkenyl having 2 to 7 C atoms.

[0152] The medium preferably comprises one or more compounds of the formula I-4, which are preferably selected from the group of compounds of the formulae I-4a to I-4e, particularly preferably the group of compounds of the formula I-4b:

[0153]

[0154]

[0155] Where R 1 R has the meaning indicated above for formula I and preferably denotes non-fluorinated alkyl having 1 to 7 C atoms or non-fluorinated alkenyl having 2 to 7 C atoms.

[0156] The medium preferably comprises one or more compounds of the formula I-5, which are preferably selected from the group of compounds of the formulae I-5a to I-5d, particularly preferably compounds of the formula I-5b:

[0157]

[0158] Where R 1 R has the meaning indicated above for formula I and preferably denotes non-fluorinated alkyl having 1 to 7 C atoms or non-fluorinated alkenyl having 2 to 7 C atoms.

[0159] The medium preferably comprises one or more compounds of formula II, which are preferably selected from the group of compounds of formulae II-1 to II-3, preferably from the group of compounds of formulae II-1 and II-2:

[0160]

[0161]

[0162] The radicals occurring therein have the meanings given above under formula II, and

[0163] Preferably R 2represents a non-fluorinated alkyl or alkoxy group having 1 to 7 C atoms or a non-fluorinated alkenyl group having 2 to 7 C atoms, and

[0164] and One of them said

[0165]

[0166] and the other independently expresses

[0167]

[0168] Preferably

[0169]

[0170] Most preferably

[0171]

[0172] And preferably,

[0173] R 2 Represents C n H 2n+1 or CH2=CH-(CH2) Z ,and

[0174] n represents an integer in the range of 1 to 7, preferably in the range of 2 to 6 and particularly preferably in the range of 3 to 5, and

[0175] z represents 0, 1, 2, 3 or 4, preferably 0 or 2.

[0176] The compound of formula II-1 is preferably selected from the group of compounds of formulae II-1a to II-1e:

[0177]

[0178] in

[0179] R 2 has the meaning indicated above and preferably means C n H 2n+1 or CH2=CH-(CH2) Z ,and

[0180] n represents an integer in the range of 1 to 7, preferably in the range of 2 to 6 and particularly preferably in the range of 3 to 5, and

[0181] z represents 0, 1, 2, 3 or 4, preferably 0 or 2.

[0182] The compound of formula II-2 is preferably selected from the group of compounds of formula II-2a to formula II-2b:

[0183]

[0184] in

[0185] R 2 has the meaning indicated above, and preferably represents C n H 2n+1 or CH2=CH-(CH2) Z ,

[0186] n represents an integer in the range of 1 to 7, preferably in the range of 2 to 6 and particularly preferably in the range of 3 to 5, and

[0187] z represents 0, 1, 2, 3 or 4, preferably 0 or 2.

[0188] The compound of formula II-3 is preferably selected from the group of compounds of formulae II-3a to II-3d:

[0189]

[0190] in

[0191] R 2 has the meaning indicated above, and preferably represents C n H 2n+1 or CH2=CH-(CH2) Z ,

[0192] n represents an integer in the range of 1 to 7, preferably in the range of 2 to 6 and particularly preferably in the range of 3 to 5, and

[0193] z represents 0, 1, 2, 3 or 4, preferably 0 or 2.

[0194] The compound of formula III is preferably selected from the group of compounds of formulae III-1 to III-6, more preferably selected from the group of formulae III-1, III-2, III-3 and III-4, and particularly preferably the compound of formula III-1:

[0195]

[0196] in

[0197] Z 31 and Z 32 represents, independently of each other, trans-CH=CH- or trans-CF=CF-, preferably trans-CH=CH-, and in formula III-6, alternatively, Z 31 and Z 32 One of them may represent -C≡C- and the other group has the meaning given under formula III,

[0198] And preferably,

[0199] R 3 represents a non-fluorinated alkyl or alkoxy group having 1 to 7 C atoms or a non-fluorinated alkenyl group having 2 to 7 C atoms, and

[0200] to One of the following, preferably express

[0201]

[0202] Very preferably

[0203]

[0204] And the others are expressed independently of each other

[0205]

[0206] Preferably

[0207]

[0208] More preferably

[0209]

[0210] in

[0211] Alternatively,

[0212] And preferably,

[0213] R 3 Represents C n H 2n+1 or CH2=CH-(CH2) Z ,

[0214] n represents an integer in the range of 1 to 7, preferably in the range of 2 to 6 and particularly preferably in the range of 3 to 5, and

[0215] z represents 0, 1, 2, 3 or 4, preferably 0 or 2.

[0216] The compound of formula III-1 is preferably selected from the group of compounds of formulae III-1a to III-1j, more preferably selected from the group of compounds of formulae III-1a, III-1b, III-1g and III-1h, and particularly preferably selected from the group of compounds of formulae III-1b and / or III-1h:

[0217]

[0218]

[0219] in

[0220] R 3 has the meaning indicated above, and preferably represents C n H 2n+1 or CH2=CH-(CH2) Z ,

[0221] n represents an integer in the range of 1 to 7, preferably in the range of 2 to 6 and particularly preferably in the range of 3 to 5, and

[0222] z represents 0, 1, 2, 3 or 4, preferably 0 or 2.

[0223] The compound of formula III-2 is preferably a compound of formula III-2a to III-21, very preferably III-2b and / or III-2j:

[0224]

[0225]

[0226]

[0227] in

[0228] R 3 has the meaning indicated above, and preferably represents C n H 2n+1 or CH2=CH-(CH2) Z ,

[0229] n represents an integer in the range of 1 to 7, preferably in the range of 2 to 6 and particularly preferably in the range of 3 to 5, and

[0230] z represents 0, 1, 2, 3 or 4, preferably 0 or 2.

[0231] The compound of formula III-5 is preferably selected from the compounds of formula III-5a:

[0232]

[0233] R 3 has the meaning indicated above for formula III-5 and preferably represents C n H 2n+1 ,in

[0234] n represents an integer in the range of 1-7, preferably in the range of 2-6.

[0235] Furthermore, in a certain embodiment, the liquid-crystalline medium according to the invention, which may be the same as or different from the previously preferred embodiments, preferably comprises one or more compounds of the formula IV,

[0236]

[0237] in

[0238] express

[0239] s is 0 or 1, preferably 1, and preferably

[0240] express

[0241]

[0242]

[0243] Particularly preferably

[0244]

[0245] L 4 represents H or alkyl having 1 to 6 C atoms, cycloalkyl having 3 to 6 C atoms or cycloalkenyl having 4 to 6 C atoms, preferably CH3, C2H5, n-C3H7, i-C3H7, cyclopropyl, cyclobutyl, cyclohexyl, cyclopent-1-enyl or cyclohex-1-enyl, and particularly preferably CH3, C2H5, cyclopropyl or cyclobutyl,

[0246] X 4 denotes H, alkyl having 1 to 3 C atoms or halogen, preferably H, F or Cl, more preferably H or F and very especially preferably F,

[0247] R 41 To R 44 , independently of one another represent non-fluorinated alkyl or non-fluorinated alkoxy groups each having 1 to 15 C atoms, non-fluorinated alkenyl, non-fluorinated alkenyloxy or non-fluorinated alkoxyalkyl groups each having 2 to 15 C atoms, or cycloalkyl, alkylcycloalkyl, cycloalkenyl, alkylcycloalkenyl, alkylcycloalkylalkyl or alkylcycloalkenylalkyl groups each having up to 15 C atoms, and alternatively R 43 and R 44 One or both of them also represent H,

[0248] Preferably

[0249] R 41 and R 42 , independently of one another represent a non-fluorinated alkyl or non-fluorinated alkoxy group each having 1 to 7 C atoms, or a non-fluorinated alkenyl, non-fluorinated alkenyloxy or non-fluorinated alkoxyalkyl group each having 2 to 6 C atoms,

[0250] Particularly preferably

[0251] R 41 represents a non-fluorinated alkyl group having 1 to 7 C atoms or a non-fluorinated alkenyl group, a non-fluorinated alkenyloxy group or a non-fluorinated alkoxyalkyl group having 2 to 6 C atoms, and

[0252] Particularly preferably

[0253] R 42 represents a non-fluorinated alkyl or non-fluorinated alkoxy group each having 1 to 7 C atoms, and

[0254] Preferably

[0255] R 43 and R 44 represents H, non-fluorinated alkyl having 1 to 5 C atoms, non-fluorinated cycloalkyl or cycloalkenyl having 3 to 7 C atoms, non-fluorinated alkylcyclohexyl or non-fluorinated cyclohexylalkyl having 4 to 12 C atoms or non-fluorinated alkylcyclohexylalkyl having 5 to 15 C atoms, particularly preferably cyclopropyl, cyclobutyl or cyclohexyl, and very particularly preferably, R 43 and R 44 At least one of them represents n-alkyl, particularly preferably methyl, ethyl or n-propyl, and the other represents H or n-alkyl, particularly preferably H, methyl, ethyl or n-propyl.

[0256] Very preferably, the compound of formula IV is selected from the compounds of formula IV-1,

[0257]

[0258] Where R 41 and R 42 Identically or differently represent alkyl radicals having 2, 3, 4, 5 or 6 C atoms.

[0259] As used herein, the expression dielectric positivity describes compounds or components where Δε>3.0, dielectric neutrality describes those where -1.5≤Δε≤3.0, and dielectric negativity describes those where Δε<-1.5. Δε is measured at a frequency of 1kHz and at 20°C. The dielectric anisotropy of each compound is determined by the results of a solution of 10% of each individual compound in a nematic host mixture. If the solubility of each compound in the host mixture is less than 10%, the concentration is reduced to 5%. The capacitance of the test mixture is measured in both a box with a homeotropic orientation and a box with a planar orientation. The box thickness of the two types of boxes is about 20μm. The applied voltage is a rectangular wave with a frequency of 1kHz and an effective value of typically 0.5V to 1.0V, but it is always selected to be lower than the capacitance threshold of each test mixture.

[0260] Δε is defined as (ε||-ε ⊥ ), and εave . is (ε||+2ε ⊥ ) / 3.

[0261] The host mixture used for determining the physical constants of the pure compound by extrapolation is ZLI-4792 from Merck KGaA, Germany. The absolute value of the dielectric constant, the birefringence (Δn) and the rotational viscosity (γ1) of the compound are measured by the change in the respective values ​​of the host mixture after adding the compound. The concentration in the host is 10%, or 5% in the case of insufficient solubility. The value is extrapolated to a 100% concentration of the added compound.

[0262] In the examples, the phase sequence of pure compounds is given using the following abbreviations:

[0263] K: crystalline, N: nematic, SmA: smectic A, SmB: smectic B, I: isotropic.

[0264] The component having a nematic phase was measured as it was at a measuring temperature of 20° C., and all other components were treated like compounds.

[0265] In both cases, unless explicitly stated otherwise, the expression "threshold voltage" in this application refers to the optical threshold and is for a 10% relative contrast ratio (V 10 ) and the expression "saturation voltage" refers to optical saturation and is for 90% relative contrast (V 90 ). The capacitive threshold voltage (V0), also called the Freedericks threshold (V Fr ).

[0266] Unless expressly stated otherwise, the parameter ranges indicated in this application include the limit values.

[0267] The different upper and lower value limits indicated for the different property ranges combine with one another to give further preferred ranges.

[0268] Throughout the application, the following conditions and definitions apply, unless otherwise stated. All concentrations are given in weight percent and relate to the respective overall mixture, all temperature values ​​are given in degrees Celsius and all temperature differences are given in differential degrees. All physical properties are determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status November 1997, Merck KGaA (Germany) and are given for a temperature of 20°C, unless explicitly stated otherwise. The optical anisotropy (Δn) is determined at a wavelength of 589.3 nm. The dielectric anisotropy (Δε) is determined at a frequency of 1 kHz. The threshold voltage and all other electro-optical properties are determined using a test cell produced by Merck KGaA, Germany. The cell thickness of the test cell used to determine Δε is approximately 20 μm. The electrodes are 1.13 cm 2 The circular ITO electrode with a 200 mm area and a guard ring. For the homeotropic orientation (ε||), the alignment layer is SE-1211 from Nissan Chemicals, Japan, and for the planar orientation (ε||), the alignment layer is SE-1211 from Nissan Chemicals, Japan. ⊥ ), the orientation layer is polyimide AL-1054 from Japan SyntheticRubber. Using a Solatron 1260 frequency response analyzer, a sine wave and 0.3V rms The capacitance is determined by the voltage at which the light is measured. The light used in the electro-optical measurement is white light. An apparatus using a commercially available DMS instrument from Autronic-Melchers, Germany, is used here. The characteristic voltage is determined under perpendicular observation. The threshold voltage (V 10 )、Mid-gray voltage (V 50 ) and saturation voltage (V 90 ).

[0269] As in A.Penirschke et al. "Cavity Perturbat ion Method for Characterization of Liquid Crystals up to 35GHz", 34 thThe liquid crystal media described in the European Microwave Conference—Amsterdam, pp. 545-548, were investigated in the microwave frequency range with respect to their properties. In this respect, A. Gaebler et al. "Direct Simulation of Material Permittivity ...", 12 MTC 2009—International Instrumentation and Measurement Technology Conference, Singapore, 2009 (IEEE), pp. 463-467 and DE 10 2004 029 429 A were also compared, in which the measurement methods are likewise described in detail.

[0270] Liquid crystals are introduced into polytetrafluoroethylene (PTFE) or quartz capillaries. The inner diameter of the capillary is 0.5 mm and the outer diameter is 0.78 mm. The effective length is 2.0 cm. The filled capillary is introduced into the center of a cylindrical cavity with a resonant frequency of 19 GHz. The length of the cavity is 11.5 mm and the radius is 6 mm. An input signal (source) is then applied and the frequency-dependent response of the cavity is recorded using a commercial vector network analyzer (N5227APNA microwave network analyzer, Keysight Technologies Inc. USA). For other frequencies, the dimensions of the cavity are adapted accordingly.

[0271] The change in resonance frequency and Q factor between the measurement using a capillary filled with liquid crystal and the measurement using a capillary not filled with liquid crystal is used to determine the dielectric constant and loss angle at the corresponding target frequency, which is obtained by the above-mentioned publication A. Penirschke et al., 34 th Equations 10 and 11 are determined as described in European Microwave Conference—Amsterdam, pp. 545-548.

[0272] The values ​​of the components of the properties perpendicular and parallel to the director of the liquid crystal are obtained by the alignment of the liquid crystal in a magnetic field. For this purpose, the magnetic field of a permanent magnet is used. The magnetic field strength is 0.35 Tesla.

[0273] In this application, the term "compound" means one compound as well as a plurality of compounds, unless specifically stated otherwise.

[0274] The dielectric anisotropy in the microwave range is defined as

[0275] Δε r ≡(ε r,|| -ε r,⊥ ).

[0276] The tunability (τ) is defined as

[0277] τ≡(Δε r / ε r,|| ).

[0278] Material quality (η) is defined as

[0279] η≡(τ / tanδ εr,max. ),in

[0280] The maximum dielectric loss is

[0281] tanδ εr,max. ≡max.{tanδ εr,⊥, ; tanδ εr,||}.

[0282] The liquid crystals used are individual substances or mixtures, which preferably have a nematic phase.

[0283] All mixtures according to the present invention are nematic. The liquid crystal medium according to the present invention preferably has a nematic phase within the preferred range given above. Here, the statement that it has a nematic phase means that on the one hand, no smectic phase is observed at low temperatures at the corresponding temperature and no crystallization is observed, and on the other hand, no clearing occurs when heated from the nematic phase. At high temperatures, the clearing point is measured in a capillary by conventional methods. The study at low temperature is carried out in a flow viscometer at the corresponding temperature and is checked by the storage of bulk samples: at a given temperature T, the storage stability (LTS) in the bulk of the medium according to the present invention is determined by visual inspection. 2g of the medium of interest is filled into a closed glass container (bottle) of a suitable size placed in a refrigerator at a predetermined temperature. Check the bottle at a defined time interval whether a smectic phase or crystallization occurs. For each material and each temperature, two bottles are stored. If the appearance of crystallization or smectic phase is observed in at least one of the two corresponding bottles, the test is terminated, and the time of the last inspection before the appearance of a higher ordered phase is observed is recorded as the corresponding storage stability. Finally the test was terminated after 1000 hours, ie an LTS value of 1000 hours means that the mixture was stable at a given temperature for at least 1000 hours.

[0284] The liquid crystal medium according to the invention may contain other additives and chiral dopants in the usual concentrations. The total concentration of these other components is 0% to 10%, preferably 0.1% to 6%, based on the entire mixture. The concentration of the individual compounds used is preferably 0.1% to 3% each. When the values ​​and concentration ranges of the liquid crystal components and liquid crystal compounds of the liquid crystal medium are quoted in this application, the concentrations of these and similar additives are not taken into account.

[0285] Optionally, the medium according to the invention may contain other liquid crystal compounds to adjust the physical properties. Such compounds are known to those skilled in the art. Their concentration in the medium according to the invention is preferably from 0% to 30%, more preferably from 0.1% to 20% and most preferably from 1% to 15%.

[0286] The liquid crystal medium according to the present invention consists of a plurality of compounds, preferably 3 to 30, more preferably 4 to 20 and very preferably 4 to 16 compounds. These compounds are mixed in a conventional manner. Usually, the desired amount of compound used in a smaller amount is dissolved in the compound used in a larger amount. If the temperature is above the clearing point of the compound used in a higher concentration, it is particularly easy to observe that the dissolution process is complete. However, the medium can also be prepared in other conventional ways, for example using a so-called premix, which can, for example, be a homogeneous mixture or a eutectic mixture of compounds, or using a so-called "multi-bottle" system, the components of which are themselves ready-to-use mixtures.

[0287] All temperatures, such as melting points T(C, N) or T(C, S), the transition from the smectic (S) phase to the nematic (N) phase T(S, N) and the clearing point of the liquid crystal T(N, I), are expressed in degrees Celsius. All temperature differences are expressed as a difference in degrees.

[0288] In the present text, the structures of the mesogenic compounds are indicated with the aid of abbreviations (also called acronyms). In these acronyms, the chemical formulae are abbreviated as follows using the following Tables A to C. All groups C n H 2n+1 , C m H 2m+1 and C l H 2l+1 and C n H 2n-1 , C m H 2m-1 and C l H 2l-1 = represents a straight-chain alkyl or alkylene group, respectively, having in each case n, m or 1 C atoms, wherein n and m are independently 1, 2, 3, 4, 5, 6 or 7, and 1 is 1, 2 or 3. Table A lists the codes for the ring elements of the core structures of the compounds, while Table B shows the linking groups and the terminal groups. Table C shows the illustrative structures of the compounds and their corresponding abbreviations.

[0289] Table A: Ring elements

[0290]

[0291]

[0292]

[0293]

[0294]

[0295]

[0296] Table B: Linking Groups

[0297]

[0298] Table B: End Groups

[0299]

[0300]

[0301] Use in combination with other

[0302]

[0303] wherein n and m each represent an integer, and the triple dots "..." are placeholders for other abbreviations from this table.

[0304] The branched side groups are numbered starting from the position immediately adjacent to ring (1), with the longest chain selected, the lower number indicating the branch length, and the superscript number in brackets indicating the branch position, for example:

[0305]

[0306] The following table shows illustrative structures and their corresponding abbreviations. These are shown to illustrate the meaning of the abbreviation conventions. They further indicate preferred compounds for use.

[0307] Table C: Illustrative Structure

[0308] The following illustrative structures are examples and compounds which are preferably additionally used in the medium:

[0309]

[0310]

[0311]

[0312]

[0313]

[0314]

[0315]

[0316]

[0317]

[0318]

[0319]

[0320]

[0321]

[0322]

[0323]

[0324] wherein m and n are the same or different and are 1, 2, 3, 4, 5, 6 or 7.

[0325] Preferably, the medium according to the invention comprises one or more compounds chosen from the compounds of Table C.

[0326] Unless indicated otherwise, parts or percentages are parts or percentages by weight.

[0327] In the above and below:

[0328] V o Indicates the threshold voltage at 20°C, capacitive [V]

[0329] n e Indicates the extraordinary refractive index at 20°C and 589nm.

[0330] n o It represents the ordinary refractive index at 20℃ and 589nm.

[0331] Δn represents the optical anisotropy at 20°C and 589 nm.

[0332] ε ⊥ represents the dielectric permittivity perpendicular to the director at 20°C and 1kHz,

[0333] ε || represents the dielectric permittivity parallel to the director at 20°C and 1kHz,

[0334] Δε represents the dielectric anisotropy at 20°C and 1kHz,

[0335] c lp,T(N,I) represents the clearing point [℃],

[0336] γ1 represents the rotational viscosity [mPa·s] measured at 20°C,

[0337] K1 represents the elastic constant at 20°C, the “bending” deformation [pN],

[0338] K2 represents the elastic constant at 20°C, "twist" deformation [pN],

[0339] K3 represents the elastic constant at 20°C, "bending" deformation [pN],

[0340] K avg. represents the average elastic constant, which is defined as and

[0341] LTS stands for Low Temperature Stability (Nematic Phase) determined as detailed in test cells or in bulk.

[0342] Unless expressly stated otherwise, all values ​​indicated in this application with respect to temperature, such as melting point T(C,N), transition from smectic (S) phase to nematic (N) phase T(S,N) and clearing point T(N,I) or cl.p., are indicated in degrees Celsius (°C). Mp denotes melting point. Furthermore, Tg=glassy state, C=crystalline state, N=nematic phase, S=smectic phase and I=isotropic phase. The numbers between these symbols denote transition temperatures.

[0343] Unless explicitly indicated otherwise, the term "threshold voltage" used in the present invention relates to the capacitive threshold (V0), also known as the Freedericksz threshold. In embodiments, as is commonly used, the optical threshold (V 10 ).

[0344] The display used to measure the capacitance threshold voltage consisted of two plane-parallel glass outer plates with a spacing of 20 μm, each with an electrode layer on the inside and an unrubbed polyimide alignment layer on top, which achieved vertical edge alignment of the liquid crystal molecules.

[0345] The clearing point was measured using a Metter Thermosystem FP900. The optical anisotropy (Δn) was measured using an Abbe Refractometer H005 (sodium spectrum lamp Na10 at 589 nm, 20°C). The dielectric anisotropy (Δε) was measured using an LCR-Meter E4980A / Agilent (G005) (ε parallel box with JALS2096-R1) at 20°C. The on-voltage (V0) was measured using an LCR-Meter E4980A / Agilent (G005) (ε parallel box with JALS2096-R1) at 20°C. The rotational viscosity (γ1) was measured using a TOYO LCM-2 (0002) (γ1 negative box with JALS-2096-R 1) at 20°C. Elastic constants (K1, splay) were measured at 20°C using LCR-Meter E4980A / Agilent (G005) (ε parallel cell with JALS2096-R1). K3: Elastic constants (K3, bending) were measured at 20°C using LCR-Meter E4980A / Agilent (G005) (ε parallel cell with JALS2096-R1). Example

[0346] Synthesis Example

[0347] abbreviation:

[0348] dist. distillation

[0349] DABCO 1,4-diazabicyclo[2.2.2]octane

[0350] THF Tetrahydrofuran

[0351] MTB ether methyl-tert-butyl ether

[0352] XPhos 2-Dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl XPhos Pd G2 Chloro(2-dicyclohexylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl)[2-(2'-amino-1,1'-biphenyl)palladium(II)

[0353] Synthesis Example 1: 4-Butyl-4'-[2-(3-fluoro-4-isothiocyanato-5-methylphenyl)ethynyl]-1,1'-biphenyl

[0354] Step 1.1: [4-(4-Butylphenyl)phenyl]ethynyl-trimethyl-silane

[0355]

[0356] A mixture of 1-bromo-4-(4-butylphenyl)benzene (CAS 63619-54-5, 33.5 g, 116 mmol), triethylamine (135 mL), bis(triphenylphosphine)palladium(II) chloride (3.2 g, 4.6 mmol), copper(I) iodide (530 mg, 2.8 mmol) and trimethylsilyl acetylene (33.6 mL, 237 mmol) was heated at reflux temperature overnight. Distilled water and MTB ether were then added to the reaction mixture. The layers were separated and the aqueous layer was extracted with MTB ether. The combined organic layers were washed with distilled water, dried (sodium sulfate) and concentrated in vacuo. The residue was purified by flash chromatography (heptane) to give [4-(4-butylphenyl)phenyl]ethynyl-trimethyl-silane as an orange solid.

[0357] Step 1.2: 1-Butyl-4-(4-ethynylphenyl)benzene

[0358]

[0359] Tetra-n-butylammonium fluoride (113 mL, 1 M in THF) was slowly added to a solution of [4-(4-butylphenyl)phenyl]ethynyl-trimethyl-silane (34.6 g, 113 mmol) in THF (650 mL) at 10°C. The reaction mixture was stirred overnight at room temperature. Distilled water, hydrochloric acid (1 M) and MTB ether were then added to the reaction mixture. The phases were separated and the aqueous phase was extracted with MTB ether. The combined organic phases were washed with brine, dried (sodium sulfate) and concentrated in vacuo. The residue was purified by flash chromatography (heptane) to give 1-butyl-4-(4-ethynylphenyl)benzene as a light yellow solid.

[0360] Step 1.3: 4-(2-{4'-butyl-[1,1'-biphenyl]-4-yl}ethynyl)-2-fluoro-6-methylaniline

[0361]

[0362] A mixture of 1-butyl-4-(4-ethynylphenyl)benzene (4.0 g, 17 mmol) and 4-bromo-2-fluoro-6-methylaniline (3.6 g, 17 mmol) in diisopropylamine (40 mL) and THF (40 mL) was heated to 70° C. under a nitrogen atmosphere. XPhos PD G2 (27 mg, 0.03 mmol), XPhos (16 mg, 0.03 mmol) and copper (I) iodide (3.3 mg, 0.02 mmol) were then added, and the reaction mixture was stirred at 70° C. overnight. It was then filtered and concentrated in vacuo. The residue was purified by flash chromatography (heptane and heptane / MTB ether) to give 4-(2-{4′-butyl-[1,1′-biphenyl]-4-yl}ethynyl)-2-fluoro-6-methylaniline as a light brown solid.

[0363] Step 1.4: 4-Butyl-4'-[2-(3-fluoro-4-isothiocyanato-5-methylphenyl)ethynyl]-1,1'-biphenyl

[0364]

[0365] Thiophosgene (1.75 mL, 22 mmol) was added dropwise to a mixture of 4-(2-{4'-butyl-[1,1'-biphenyl]-4-yl}ethynyl)-2-fluoro-6-methylaniline (7.2 g, 20 mmol) and 1,4-diazabicyclo[2.2.2]octane (5.6 g, 50 mmol) in dichloromethane (75 mL) at 0°C, and the reaction mixture was stirred at room temperature for 1 hour. It was hydrolyzed with brine, and the phases were separated. The aqueous phase was washed with dichloromethane, and the combined organic phases were dried (sodium sulfate) and concentrated in vacuo. The residue was purified by flash chromatography (heptane) and crystallization from heptane to give 4-butyl-4'-[2-(3-fluoro-4-isothiocyanato-5-methylphenyl)ethynyl]-1,1'-biphenyl as pale yellow crystals.

[0366] Phase sequence: K 83SmA 102N 172I

[0367] Δn=0.4800

[0368] Δε=14.4

[0369] Synthesis Example 2: 5-[2-(4-butylphenyl)ethynyl]-1-fluoro-2-isothiocyanato-3-methylbenzene

[0370] Step 2.1: 4-[2-(4-Butylphenyl)ethynyl]-2-fluoro-6-methylaniline

[0371]

[0372] Under nitrogen atmosphere, a solution of 1-butyl-4-ethynylbenzene (CAS 79887-09-5) (3.0 g, 19 mmol) and 4-bromo-2-fluoro-6-methylaniline (CAS 429683-46-5) (3.9 g, 19 mmol) in diisopropylamine (45 mL) and tetrahydrofuran (50 mL) was heated to 70° C. XPhos Pd G2 (30 mg, 0.04 mmol), XPhos (18 mg, 0.04 mmol) and copper (I) iodide (3.6 mg, 0.02 mmol) were then added and the reaction mixture was stirred at 70° C. for 72 hours. It was then filtered and concentrated in vacuo. The residue was purified by silica gel chromatography with heptane / toluene to give 4-[2-(4-butylphenyl)ethynyl]-2-fluoro-6-methylaniline as a light brown oil.

[0373] Step 2.2: 5-[2-(4-Butylphenyl)ethynyl]-1-fluoro-2-isothiocyanato-3-methylbenzene

[0374]

[0375] Thiophosgene (1.5 mL, 20 mmol) was added dropwise to a mixture of 4-[2-(4-butylphenyl)ethynyl]-2-fluoro-6-methylaniline (5.0 g, 18 mmol) and DABCO (5.0 g, 44 mmol) in dichloromethane (65 mL) at 0° C., and the reaction mixture was stirred at room temperature for 1 hour. It was hydrolyzed with brine, and the phases were separated. The aqueous phase was washed with dichloromethane, and the combined organic phases were dried (sodium sulfate) and concentrated in vacuo. The residue was purified by silica gel chromatography with heptane and by RP flash chromatography with acetonitrile to give 5-[2-(4-butylphenyl)ethynyl]-1-fluoro-2-isothiocyanato-3-methylbenzene as a colorless oil.

[0376] Phase sequence: Tg-57I

[0377] Δn=0.3367

[0378] Δε=13.2

[0379] γ1=119mPas

[0380] Synthesis Example 3: 4'-[2-(4-butylphenyl)ethynyl]-3-fluoro-4-isothiocyanato-5-methyl-1,1'-biphenyl

[0381] Step 3.1: 2-Fluoro-6-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline

[0382]

[0383] A mixture of 4-bromo-2-fluoro-6-methylaniline (CAS 429683-46-5, 17.0 g, 83 mmol), potassium acetate (24.5 g, 250 mmol), [1,1'-bis(diphenylphosphino)ferrocene]-dichloropalladium(II) (1.8 g, 2.5 mmol) and bis-(pinacolato)-diboron (25.9 g, 100 mmol) in 1,4-dioxane (200 mL) was heated at reflux temperature overnight. The reaction was then quenched by the addition of distilled water and MTB ether. The phases were separated and the aqueous phase was extracted with MTB ether. The combined organic phases were washed with distilled water and brine, dried (sodium sulfate) and concentrated in vacuo. The residue was purified by flash chromatography (dichloromethane) to give 2-fluoro-6-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline as an orange oil.

[0384] Step 3.2: 4'-Bromo-3-fluoro-5-methyl-[1,1'-biphenyl]-4-amine

[0385]

[0386] Under nitrogen atmosphere, a mixture of 2-fluoro-6-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline (12.0 g, 48 mmol), 1-bromo-4-iodobenzene (15.2 g, 53 mmol) and sodium carbonate (12.2 g, 115 mmol) in isopropanol (30 mL), toluene (90 mL) and distilled water (65 mL) was stirred for 1 hour. Bis(triphenylphosphine)-palladium(II) chloride (993 mg, 1.4 mmol) was then added and the reaction mixture was stirred at reflux temperature overnight. The phases were separated and the aqueous phase was extracted with toluene. The combined organic phases were washed with distilled water, dried (sodium sulfate) and concentrated in vacuo. The residue was purified by flash chromatography (heptane / MTB ether) to give 4'-bromo-3-fluoro-5-methyl-[1,1'-biphenyl]-4-amine as a colorless solid.

[0387] Step 3.3: 4'-[2-(4-Butylphenyl)ethynyl]-3-fluoro-5-methyl-[1,1'-biphenyl]-4-amine

[0388]

[0389] A mixture of 1-butyl-4-ethynylbenzene (CAS 79887-09-5, 1.5 g, 10 mmol) and 4'-bromo-3-fluoro-5-methyl-[1,1'-biphenyl]-4-amine (2.5 g, 9 mmol) in diisopropylamine (25 mL) and THF (25 mL) was slowly heated under nitrogen atmosphere. XPhos PD G2 (15 mg, 0.02 mmol), XPhos (9 mg, 0.02 mmol) and copper (I) iodide (1.8 mg, 0.01 mmol) were added, the reaction mixture was stirred at reflux temperature for 4 hours, filtered and concentrated in vacuo. The residue was purified by flash chromatography (heptane and toluene) to give 4'-[2-(4-butylphenyl)ethynyl]-3-fluoro-5-methyl-[1,1'-biphenyl]-4-amine as a colorless solid.

[0390] Step 3.4: 4'-[2-(4-Butylphenyl)ethynyl]-3-fluoro-4-isothiocyanato-5-methyl-1,1'-biphenyl

[0391]

[0392] Thiophosgene (0.6 mL, 8 mmol) was added dropwise to a mixture of 4'-[2-(4-butylphenyl)ethynyl]-3-fluoro-5-methyl-[1,1'-biphenyl]-4-amine (2.5 g, 7 mmol) and DABCO (2.0 g, 18 mmol) in dichloromethane (25 mL) at 0°C. The reaction mixture was stirred at room temperature for 1 hour, hydrolyzed with brine, and the layers were separated. The aqueous phase was washed with dichloromethane, and the combined organic phases were dried (sodium sulfate) and concentrated in vacuo. The residue was purified by flash chromatography (heptane) and crystallization from heptane to give pale yellow crystals of 4'-[2-(4-butylphenyl)ethynyl]-3-fluoro-4-isothiocyanato-5-methyl-1,1'-biphenyl.

[0393] Phase sequence: K 73SmA 172I.

[0394] Δn=0.4652

[0395] Δε=16.5

[0396] Synthesis Example 4: 1-Fluoro-2-isothiocyanato-3-methyl-5-{2-[4-(4-propylcyclohexyl)-phenyl]ethynyl}benzene

[0397] Step 4.1: 2-Fluoro-6-methyl-4-{2-[4-(4-propylcyclohexyl)phenyl]ethynyl}aniline

[0398]

[0399] Under nitrogen atmosphere, a solution of 4-(4-propyl-cyclohexyl)-phenylacetylene (CAS 167858-58-4) (5.4 g, 24 mmol) and 4-bromo-2-fluoro-6-methylaniline (CAS 429683-46-5) (4.6 g, 23 mmol) and diisopropylamine (55 mL) in THF (60 mL) was heated to 70° C. XPhos Pd G2 (35 mg, 0.05 mmol), XPhos (21 mg, 0.05 mmol) and copper (I) iodide (4 mg, 0.02 mmol) were then added, and the reaction mixture was stirred at 70° C. overnight. It was then filtered and concentrated in vacuo. The residue was purified by silica gel chromatography (heptane / methyl tert-butyl ether) to give 2-fluoro-6-methyl-4-{2-[4-(4-propylcyclohexyl)phenyl]ethynyl}aniline as a light brown solid.

[0400] Step 4.2: 1-Fluoro-2-isothiocyanato-3-methyl-5-{2-[4-(4-propylcyclohexyl)phenyl]-ethynyl}benzene

[0401]

[0402] Thiophosgene (1.7 mL, 22 mmol) was added dropwise to a mixture of 2-fluoro-6-methyl-4-{2-[4-(4-propylcyclohexyl)phenyl]ethynyl}aniline (7.0 g, 20 mmol) and DABCO (5.6 g, 50 mmol) in dichloromethane (75 mL) at 0°C, and the reaction mixture was stirred at room temperature for 1 hour. It was hydrolyzed with brine, and the phases were separated. The aqueous phase was washed with dichloromethane, and the combined organic phases were dried (sodium sulfate) and concentrated in vacuo. The residue was purified by silica gel chromatography (heptane) and crystallization from heptane. The crude product was purified by flash chromatography (toluene and heptane) and crystallization from heptane to give white crystals of 1-fluoro-2-isothiocyanato-3-methyl-5-{2-[4-(4-propylcyclohexyl)phenyl]ethynyl}benzene.

[0403] Phase sequence: K 89 N 109 I.

[0404] Δn=0.3722

[0405] Δε=13.9

[0406] Similar to Synthesis Examples 1 to 4, the following compounds were obtained:

[0407]

[0408]

[0409]

[0410]

[0411]

[0412]

[0413]

[0414]

[0415]

[0416]

[0417]

[0418]

[0419] Application Testing

[0420] Nematic liquid crystal host mixture N1, example mixtures M1 to M4 and comparative example mixtures C1 to C4 having the composition and properties as indicated in the following table were prepared and characterized with respect to their general physical properties and their suitability in microwave devices at 19 GHz and 20°C.

[0421] The comparative mixtures contained compounds known from the prior art corresponding to Synthesis Examples 1 to 4, wherein the 1-fluoro-2-isothiocyanato-3-methyl-phenylhead group was replaced by a 1,3-difluoro-2-isothiocyanato-phenylhead group.

[0422] Mixture N1

[0423]

[0424]

[0425] Example mixture M1 consists of 90% of main mixture N1 and 10% of compound PPTG(1)-4-S of Synthesis Example 1.

[0426] Example mixture M2 is composed of 90% of main mixture N1 and 10% of compound PTG(1)-4-S of Synthesis Example 2.

[0427] Example mixture M3 is composed of 90% of main mixture N1 and 10% of compound PTPG(1)-4-S of Synthesis Example 3.

[0428] Example mixture M4 is composed of 90% of main mixture N1 and 10% of compound CPTG(1)-3-S of Synthesis Example 4.

[0429] Comparative mixture C1 consisted of 90% of host mixture N1 and 10% of compound PPTU-4-S.

[0430] Comparative mixture C2 consisted of 90% of host mixture N1 and 10% of compound PTU-4-S.

[0431] Comparative mixture C3 consists of 90% of host mixture N1 and 10% of compound PTPU-4-S.

[0432] Comparative mixture C4 consisted of 90% of host mixture N1 and 10% of compound CPTU-3-S.

[0433] The following results are obtained:

[0434]

[0435]

[0436] It can be seen that the compounds of formula G according to the present invention exhibit the same tunable values ​​(τ) as the compounds of the prior art.

[0437] Surprisingly, the specific head groups of the compounds according to the invention have improved miscibility with other polar compounds. Since these polar compounds generally have limited solubility in the host material, the overall proportion of compounds with high tunability in the medium can be increased by adding compounds of formula G, thereby achieving better tunability of the medium for microwave applications.

Claims

1. A compound of formula G, in R G represents H, non-fluorinated straight-chain alkyl having 1 to 12 C atoms or non-fluorinated straight-chain or branched alkenyl having 2 to 12 C atoms, wherein one or more CH2- groups may be replaced by substituted, and one or more non-adjacent CH2-groups may be replaced by -O-, Z G1 and Z G2 , identically or differently represent -CH=CH-, -CF=CF-, -CH=CF-, -CF=CH-, -C≡C-, -C≡CC≡C- or a single bond, X represents Cl or F, R represents a straight chain, branched chain or cyclic alkyl group having 1 to 6 C atoms, t is 0, 1, or 2, and and Identically or differently represent a group selected from the following group: a) the group consisting of 1,4-phenylene, 1,4-naphthylene and 2,6-naphthylene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L, b) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydronaphthalene-2,6-diyl, tetrahydronaphthalene-5,8-diyl, decahydronaphthalene-2,6-diyl, bicyclo[1.1.1]pentane-1,3-diyl, 4,4′-bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl and spiro[3.3]heptane-2,6-diyl, in which one or two CH groups may be replaced by N, one or more non-adjacent CH2 groups may be replaced by -O- and / or -S-, and in which one or more H atoms may be replaced by L, c) the group consisting of thiophene-2,5-diyl, thieno[3,2-b]thiophene-2,5-diyl, selenophene-2,5-diyl, each of which may also be mono- or poly-substituted by L, L, identically or differently on each occurrence, represents F, Cl, CN, SCN, SF5 or linear or branched, in each case optionally fluorinated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, each having 1 to 12 C atoms.

2. A compound according to claim 1, wherein R represents a methyl group.

3. A compound according to claim 1 or 2, wherein X represents fluorine.

4. A compound according to claim 1 or 2, wherein the compound is selected from the compounds of formula G-1 to G-6, Where R G , Z G1 , Z G2 , and has the meaning given in claim 1.

5. A compound according to claim 1 or 2, wherein Z G1 and Z G2 It means -CF=CF- or -C≡C-.

6. A compound according to claim 1 or 2, wherein and express Where R L represents, identically or differently on each occurrence, H or alkyl having 1 to 6 C atoms, Or One or more H atoms may be ligated to the radical R L or F substitution, where R L represents H or an alkyl group having 1 to 6 C atoms.

7. A liquid-crystalline medium comprising one or more compounds of the formula G according to any one of claims 1 to 6.

8. A component for high frequency technology, characterized in that It comprises a liquid-crystalline medium according to claim 7.

9. The component of claim 8, wherein the component is a liquid crystal based antenna element, a phase shifter, a tunable filter, a tunable metamaterial structure, a matching network or a varactor diode.

10. A microwave antenna array, characterized in that It comprises one or more components according to claim 8 or 9.

11. A process for the manufacture of a compound of formula G according to any one of claims 1 to 6, characterized in that reacting a compound of formula N with carbon disulfide or with a thiocarbonic acid derivative XC(=S)-Y, wherein X and Y are identical or different leaving groups, The radicals and parameters occurring therein have the meanings given in claim 1.

Images