WO2012126570A1 - Compositions for a liquid crystalline medium and application thereof in high frequency components - Google Patents

Abstract

The invention relates to combinations having at least one bicyclic or tricyclic ring system, which is connected by acetylene ethylene or difluoroethylene bridges, to the application thereof in high frequency components, to liquid crystalline media containing the compositions, and to high frequency components containing such media, in particular antennas, especially for the gigahertz range. The liquid crystalline media are used to phase shift microwaves for tunable phased-array antennas, for example.

Description

 Compounds for a liquid crystalline medium and their use for high frequency components

The present invention relates to compounds having at least one bicyclic or tricyclic ring system, which with acetylene or

Difluorethylenbrücken is connected, their use for

High frequency components, liquid crystalline media containing the

Connections and high-frequency components containing these media, in particular antennas, especially for the gigahertz range. The

Liquid-crystalline media are used, for example, for phase shifting microwaves for tunable 'phased-array' antennas.

Liquid-crystalline media have long been in electro-optical

Displays (Liquid Crystal Displays - LCDs) used to display information.

1, 4-Diethinylbenzolderivate be in the publications EP 0968988 A1, DE 19907941 A1, DE 10120024 A1 and JP 08012599 A as

liquid crystalline components proposed. Compounds having a (difluoro) ethylene bridge between two rings are not disclosed therein. Lately, however, liquid-crystalline media for the

Use in components or in components for which

Microwave technology proposed, such. in DE 10 2004 029 429 A and in JP 2005-120208 (A).

A technically valuable application of the liquid-crystalline media in high-frequency technology is based on their property that they can be controlled by a variable voltage in their dielectric properties, especially for the gigahertz range. Thus can be tuned

Design antennas that do not contain moving parts (A.

Gaebler, A. Moessinger, F. Goelden, et al., "Liquid Crystal Reconfigurable Antenna Concepts for Space Applications at Microwave and Millimeter Waves, "International Journal of Antennas and Propagation, vol. 2009, Article ID 876989, 7 pages, 2009. doi: 10.1155 / 2009/876989).

The document A. Penirschke, S. Mueller, P. Scheele, C. Weil, M. Wittek, C. Hock and R. Jakoby: "Cavity Pertubation Method for Characterization of Liquid Crystals up to 35 GHz", 34 ^th European Microwave Conference Amsterdam, 545-548 describes, inter alia, the properties of the known single liquid crystalline substance K15 (Merck KGaA,

Germany) at a frequency of 9 GHz.

1- (phenylethynyl) tolanes, also referred to below as bistolan compounds, with an alkyl substitution on the central phenylene ring are known to the person skilled in the art. For example, discloses the publication S.-T. Wu, C.-S. Hsu, K.-F. Shyu Appl. Phys. Lett. (1999), 74 (3), 344-346 various liquid crystalline bistolane compounds having a lateral methyl group of the formula

C.S. Hsu, K.F. Shyu, Y.Y. Chuang, S.-T. Wu Liq. Cryst. (2000), 27 (2), 283-287 discloses, besides such liquid crystalline bistolane compounds having a lateral methyl group, also corresponding compounds having a lateral ethyl group, and suggests their use, among others. in "liquid crystal optically phased arrays".

DE 10 2004 029 429 A (see above) describes the use of conventional liquid-crystal media in microwave technology, inter alia in phase shifters. There, liquid-crystalline media are already being investigated for their properties in the corresponding frequency range. A compound of the formula

or derived derivatives are described as constituents of

organic thin-film transistors (EP 2 073 290 A1), as

Photosensitizing dyes for controlling a "photoacid generating system" (WO 2008/021208 A2) and as constituents of data recording media (JP 2004-082439 A)

Properties and their use in liquid-crystalline media are not yet described. EP 2 073 290 A1 also mentions the following compounds:

 In each case the four symmetrically substituted molecules are mentioned.

However, the previously known compositions or individual compounds are generally associated with disadvantages. Most of them, among other deficiencies, lead to unfavorably high losses and / or inadequate phase shifts or material quality.

For use in high-frequency technology, liquid-crystalline media with special, hitherto unusual, unusual properties or combinations of properties are needed. Thus, new components for liquid-crystalline media are with

improved properties required. In particular, the loss in the microwave range must be reduced and the material quality (η) to be improved. Tunable antennas also require liquid crystalline media with fast response time to a changed voltage between the electrodes of the cell.

There is also a need to improve the low-temperature behavior of the components. Here are both an improvement of

Operating characteristics, as well as the shelf life required.

There is therefore a considerable need for liquid-crystalline media with suitable properties for corresponding practical applications.

Surprisingly, it has been found that the invention

Compounds have broad nematic phases and high clearing points (transition of the nematic phase into the isotropic phase). At the same time, the optical anisotropy (An) is in a favorable range for the phase shift of microwaves. Taking advantage of this effect, it has now surprisingly been found that liquid crystalline media having a suitable, nematic phase range and high Δη can be realized with the compounds according to the invention, which do not have the disadvantages of the materials of the prior art or at least only to a considerably lesser extent.

The invention relates to compounds of the formula I,

wherein



nicht benachbarte -CH₂- durch X ersetzt sein können, und R³ wie R¹ definiert ist,

non-adjacent -CH ₂ - may be replaced by X, and R ³ is defined as R ¹ ,

 b) 1,4-phenylene, in which one or more, preferably one or two, CH groups may be replaced by N,

 c is a remainder of the formulas

 d) trans-1, 4-cyclohexylene or cyclohexenylene, in which also one or two non-adjacent Ch 1 groups may be replaced by -O- and / or -S- and in which H may be replaced by F,

or

e) a radical from the group, 4-bicyclo (2,2,2) octyl, cyclobutane-1, 3-diyl, spiro [3.3] heptane-2,6-diyl, thiophene-2,5-diyl, thiophene 2,4-diyl, furan-2,5-diyl, furan-2,4-diyl, and in which groups a), b), c), d) and e)

also one or more H atoms to Br, Cl, F, CN, -NCS, -SCN, SF ₅ , C ₁ -C 10 -alkyl, C ₁ -C 10 -alkoxy, C ₃ -C ₆ -cycloalkyl or a mono- or polyfluorinated C ₁ -C ₄ -alkyl radical. C ₁₀ alkyl or alkoxy group may be replaced, and wherein

at least one radical from A ² , A ³ and A ^{4 represents} a radical according to a),

R and R ² each independently represent a halogenated or unsubstituted alkyl radical having 1 to 15 C atoms, wherein in these radicals also one or more Chfe groups each independently of one another by -C = C-, -CH = CH-, -CF = CF-, -CF = CH-, -CH = CF-, - (CO) O-, -O (CO) -, - (CO) -, -O- or -S- may be replaced so that or S atoms are not directly linked,

F, Cl, Br, CN, CF _3, OCF _3l SCN, NCS or SF _5,

Z ² , Z ^{3 are} independently -C = C- or

Y ¹ , Y ^2, independently of one another, are H, F, Cl, C ¹ -C 10 -alkyl, preferably H or F, particularly preferably F,

Z ¹ , Z ^{5 are} independently a single bond, -C = C-, -CH = CH- CH 2 O-, - (CO) O-, -CF ₂ O-, -CF ₂ CF ₂ -, -CH ₂ CF ₂ -, -CH ₂ CH 2 -, - (CH ₂ ) ₄ -, -CH = CF- or -CF = CF-, where asymmetric bridges can be oriented to both sides,

P 1 or 2, and m, n are independently 0, 1 or 2

or R ¹ - (A ¹ -Z) _m -A ² - or -A - (Z ⁵ -A ⁵ ) _n -R ² independently optionally also a radical of the formulas

bedeuten.

mean.

Preferred compounds of the formula I are those in which the

Connecting the formulas

wherein R ¹ and R ^{2 are} both CH ₃ , both F or both CF3, are not included.

The double bonds of the formula -CY ¹ = CY ² - between the rings A ² to A ⁴ and optional double bonds in the groups Z ¹ and Z ⁵ preferably have the trans configuration (E configuration). The compounds according to the invention have a high clearing point, a low melting point and a high optical anisotropy (Δη). The unwanted rotation of the compounds is limited so that they are particularly suitable for use in the gigahertz range.

Advantageously, the relatively low loss factor in the microwave spectrum. The compounds alone or in mixture with other mesogenic components have a nematic phase over a broad temperature range. These properties make them particularly suitable for use in components for high frequency engineering, especially in liquid crystal phase shifters. Liquid-crystalline media according to the invention have the corresponding properties. Preferred compounds of formula I are characterized by the selection of one or more of the following parameters:

The counter m is preferably 0 or 1, more preferably 0. The counter n is preferably 0 or 1, more preferably 0. m + n is preferably 0 or

1 and more preferably 0. m + n + p is preferably 1 or 2, i. the total number of ring systems in formula I is preferably 3 or 4.

The groups A ² , A ³ and A ⁴ preferably comprise a total of one or two bicyclic or tricyclic ring groups according to definition a). Particularly preferably, the group A ^{3 is} a ring group according to definition a). The

Ring groups A ² and A ⁴ , and A ¹ and A ^5, if present, are particularly preferably an optionally substituted ring group according to definition b) or c), in particular optionally substituted 1,4-phenylene.

The bridging groups Z ¹ and Z ⁵ are, independently of each other, preferably a single bond, -C = C-, -CF = CF- or -CH = CH-, more preferably a single bond. Z ² and Z ³ are preferably -C = C- or -CF = CF-, more preferably -C = C-. Among other things, these groups support a high Δη value and good phase properties.

Y ¹ / Y ² are preferably H / F, F / H, F / F, Cl / F, CH ₃ / F, F / CH ₃ or F / Cl and more preferably F / F.

One or both of the radicals R ¹ or R ² , preferably R ¹ , preferably denotes a straight-chain alkyl radical having 1 to 15, in particular 2 to

15 C atoms, where in these radicals also one or more CH 2 groups in each case independently of one another by -C = C-, -CH = CH-,

- (CO) O-, -O (CO) -, - (CO) -, -O- can be replaced so that O atoms are not directly linked. The groups R ¹ and R ² are particularly preferably both an alkyl radical having 2 to 7 C atoms. Here, R ¹ and R ^{2 are,} for example, propyl and hexyl or butyl and butyl, furthermore propyl and pentyl, propyl and hexyl or butyl and pentyl. In a further preferred embodiment of the invention is the

Group R ^{2 is} a polar group (radical X). The group R ² = X is F, Cl, Br, CN, CF ₃ , OCF ₃ , SCN, NCS, SF ₅ or another

halogenated alkyl radical having 1 to 9 C atoms, wherein in this radical also one or more CFk groups each independently of one another by -C = C-, -CH = CH-, -CF = CF-, -CF = CH-, - CH = CF-, - (CO) O-, -O (CO) -, - (CO) -, -O- or -S- may be replaced so that O or S atoms are not directly linked to one another. Particularly preferably R ^{2 is} F, CF ₃ or OCF ₃ . The corresponding compounds of the formula I have a clearly positive dielectric anisotropy (Δε). The Δε value is preferably 3 or more.

The radical R ² therefore preferably together for both embodiments represents an alkyl radical having 2 to 15 C atoms, where in these radicals also one or more Ch groups each independently of one another by -C = C-, -CH = CH-, - ( CO) O-, -O (CO) -, - (CO) -, -O- be replaced may be that O atoms are not directly linked to each other, or F, Cl, Br, CN, CF _3> OCF ₃ , SCN, NCS, SF ₅ or a halogenated alkyl radical having 1 to 9 carbon atoms, in this rest also one or more ChV groups each independently of one another by -C = C-, -CH = CH-,

-CF = CF-, -CF = CH-, -CH = CF-, - (CO) O-, -O (CO) -, - (CO) -, -O- or -S- may be replaced, that O or S atoms are not directly linked.

Bevorzugte Ausführungsformen der Erfindung werden daher durch die folgenden beispielhaften Strukturen repräsentiert: The Rin groups according to definition b) preferably have the substructure

Preferred embodiments of the invention are therefore represented by the following exemplary structures:

unabhängig einen Alkylrest mit 2 bis 7 C-Atomen, beispielsweise einen Propylrest und die andere Gruppe einen Hexylrest oder beide Gruppen gleichzeitig einen Propyl-, Butyl-, Pentyl- oder Hexylrest bedeuten.

independently an alkyl radical having 2 to 7 carbon atoms, for example a propyl radical and the other group is a hexyl radical or both groups simultaneously a propyl, butyl, pentyl or hexyl radical.

The compounds of formula I can be advantageously prepared as shown in the following exemplary synthetic schemes (Scheme 1, 2). The symmetrical compounds of the formula I can be prepared by means of a simple Sonogashira reaction (Scheme 1):

Schema 1: Syntheseschema zur Darstellung von Verbindungen der Formel I.

Scheme 1: Synthetic scheme for the preparation of compounds of the formula I.

Asymmetric compounds of the formula (1) can be prepared in analogy to the reaction sequence shown in Scheme 2:

 Scheme 2: Synthetic scheme for the representation of asymmetric

 Compounds of the formula I.

R ^{1 2} in Scheme 1 and 2 have the meaning of R as defined for formula I. Schemes 1 and 2 show the synthesis of certain compounds. The phenyl radicals "R ¹ -phenyl" or

"R ² -phenyl" can be generalized to any radicals -A ² - (Z ¹ -A ¹ ) _m -R ¹ or -A ⁴ - (Z ⁵ -A ⁵ ) _n -R ² according to formula I. The parameters R ^{1 2} , A ^{1 "5} , Z ^1/5 , m and n are defined therein as above and below.

The liquid-crystalline media according to the present invention comprise one or more compounds of the formula I and optionally at least one further, preferably mesogenic compound. The liquid-crystalline medium therefore preferably contains two or more compounds which preferably liquid crystalline. Preferred media include the preferred compounds of formula I.

Further components of the liquid-crystalline media are preferably selected from the compounds of the formula II:

wherein

11 R ¹¹ or X ¹¹ ,

12 R ¹² or X ¹² ,

R ¹¹ and R ^{12 are} independently of each other unfluorinated alkyl or

 unfluorinated alkoxy having 1 to 17, preferably 3 to 10, C atoms or unfluorinated alkenyl, unfluorinated alkynyl, unfluorinated alkenyloxy, or unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, preferably alkyl or unfluorinated alkenyl,

X ¹¹ and X 12 independently of one another are F, Cl, Br, -CN, -NCS, -SCN,

-SF ₅ , fluorinated alkyl or fluorinated alkoxy having 1 to 7 carbon atoms or fluorinated alkenyl, fluorinated alkenyloxy or fluorinated alkoxyalkyl having 2 to 7 carbon atoms, preferably fluorinated alkoxy, fluorinated alkenyloxy, F or Cl, p, q is independently 0 or 1,

unabhängig voneinander Z ¹¹ to Z 13 are independently of one another trans- CH = CH-, trans- -CF = CF-, -C = C- or a single bond, and

independently of each other

 wherein L is independently branched or unbranched alkyl, alkenyl or alkynyl having 1 to 12 C atoms, wherein independently of one another also one or more

 "-CH 2 -" - groups may be replaced by O, C 3 -C 6 cycloalkyl, C 3 -C 6 cycloalkenyl, fluorinated alkyl or alkenyl, fluorinated alkyloxy or alkenyloxy,

F, Cl, Br, CN, NCS, SCN or SF ₅ ,

mean.

In a preferred embodiment of the present invention, the liquid-crystalline media comprise one or more compounds of the formula I and one or more compounds of the formula II.

According to the present application, the liquid-crystalline media preferably contain a total of 5 to 95%, preferably 10 to 90% and particularly preferably 15 to 80%, of compounds of the formula I. Preferably, the liquid-crystalline media according to the present invention contain compounds selected from the group of the compounds of formulas I and II, more preferably they are predominantly, even more preferably they are substantially and quite preferably they consist entirely thereof.

In this application means "included" in connection with

Compositions that the entity in question, i. the medium or component, the specified component or components or compound or compounds, preferably in a total concentration of 10% or more, and more preferably 20% or more. "Predominantly" in this context means that the entity in question contains 55% or more, preferably 60% or more and most preferably 70% or more of the indicated component or components or compound or compounds. "Substantially" in this context means that the entity in question contains 80% or more, preferably 90% or more, and most preferably 95% or more of the stated component or components or compound or compounds. "Complete" in this context means that the entity in question contains 98% or more, preferably 99% or more and most preferably 100.0% of the indicated component or components or compound or compounds. According to the present application, the liquid-crystalline media preferably contain a total of 10 to 100%, preferably 20 to 95% and particularly preferably 25 to 90%, of compounds of the formulas I and II.

According to the present invention, the compounds of formula II preferably become stronger in a total concentration of 10% to 90% preferably from 15% to 85%, even more preferably from 25% to 80% and most preferably from 30% to 75% of the total mixture.

The liquid-crystalline media may also contain other additives such as stabilizers, chiral dopants and nanoparticles. The individual compounds added are used in concentrations of 0.005 to 6%, preferably from 0.1 to 3%. The total concentration of these other ingredients is in the range of 0% to 10%, preferably 0.1% to 6%, based on the total mixture. However, the concentration data of the other constituents of the liquid-crystal mixtures, ie the liquid-crystalline or mesogenic compounds, are taken into account without taking into account the concentration of these

Additives indicated. The liquid-crystalline media preferably contain 0 to 10% by weight, in particular 0.01 to 5% by weight and more preferably 0.1 to 3% by weight, of stabilizers. Preferably, the media contain one or more stabilizers selected from 2,6-di-tert-butylphenols, 2,2,6,6-tetramethylpiperidines or 2-benzotriazol-2-yl-phenols. These adjuvants are known in the art and commercially available, for. B. as

Light stabilizers.

An embodiment of the invention is therefore also a process for the preparation of a liquid-crystal medium, which is characterized in that one or more compounds of the formula I is mixed with one or more further compounds and optionally with one or more additives. The further compounds are preferably selected from the compounds of the formula II, as indicated above, and optionally one or more further compounds.

In the present application, the term dielectrically positive describes compounds or components with Δε> 3.0, dielectrically neutral with -1.5 <Δε 3.0 and dielectrically negative with Δε <-1.5. The dielectric anisotropy of each compound becomes apparent from the results of a solution of 10% of each individual compound in one

determined nematic host mixture. If the solubility of each Compound in the host mixture is less than 10%, the concentration is reduced to 5%. The capacities of the test mixtures are determined in a cell with homeotropic as well as homogeneous orientation. The layer thickness is about 20 μm for both cell types. The applied voltage is a square wave with a frequency of 1 kHz and an effective value of typically 0.5V to 1.0V, but is always chosen to be below the capacitive threshold for the particular test mixture. is defined as / 3.

As a host mixture for dielectrically positive compounds is the

Mixture ZLI-4792 and for dielectrically neutral as well as for dielectrically negative compounds the mixture ZLI-3086 used, both from Merck KGaA, Germany. The absolute values of the dielectric

 Constants of the compounds are determined from the change in the respective values of the host mixture upon addition of the compounds of interest. The values are extrapolated to a concentration of the compounds of interest of 100%.

Components which have a nematic phase at the measuring temperature of 20 ° C are measured as such, all others are treated as compounds. The term threshold voltage refers to in the present

Indicate the optical threshold and are given for 10% relative contrast (V ₀ ), the term saturation voltage refers to optical saturation and is given for 90% relative contrast (V ₉₀ ), in both cases, unless expressly stated otherwise. The capacitive threshold voltage (V ₀ ), also called the Freedericks threshold VF _f , is only used if expressly stated.

The parameter ranges given in this application all include the limits unless expressly stated otherwise. The different upper and lower limits given for different ranges of properties provide additional preferred ranges in combination. Throughout this application, the following terms and definitions apply unless expressly stated otherwise. All concentrations are given in percentage by weight and refer in each case to the total mixture, all temperatures and all temperature differences are given in degrees Celsius or degree of difference. All physical properties typical of liquid crystals are calculated according to "Merck Liquid

Crystals, Physical Properties of Liquid Crystals ", as of Nov. 1997, Merck KGaA, Germany, and are listed for a temperature of 20 ° C. unless expressly stated otherwise, the optical anisotropy (Δη) is at a wavelength of 589, The dielectric anisotropy (Δε) is determined at a frequency of 1 kHz, the threshold voltages and all other electro-optical

Properties are determined with test cells manufactured at Merck KGaA, Germany. The test cells for the determination of Δε have a layer thickness of about 20 pm. The electrode is a circular ITO electrode with a surface area of 1.13 cm ² and a guard ring. The alignment layers are SE-1211 from Nissan

Chemicals, Japan, for homeotropic alignment (εμ) and polyimide AL-1054 from Japan Synthetic Rubber, Japan, for homogeneous alignment (ε ±). Capacitance is determined using a Solatron 1260 frequency response analyzer using a sine wave with a voltage of 0.3 Vrms. The light used in the electro-optical measurements is white light. In this case, a structure with a commercially available device DMS Fa. Autronic Melchers, Germany is used. The characteristic stresses are below vertical

Observation determined. The threshold voltage (\ o), mid-gray voltage (V ₅₀ ) and saturation voltage (V ₉₀ ) are determined for 10%, 50% and 90% relative contrast, respectively.

The liquid-crystalline media are investigated for their properties in the frequency range of microwaves as in A. Penirschke et al. "Cavity Perturbation Method for Characterization of Liquid Crystals up to 35GHz ", 34 European Microwave Conference - Amsterdam, pp. 545-548 See also A. Gaebler et al.," Direct Simulation of Material Permittivities 12MTC 2009 - International Instrumentation and Measurement Technology Conference, Singapore, 2009 (IEEE), p 463-467 and DE 10 2004 029 429 A, in which a measuring method is also described in detail.

The liquid crystal is filled in a capillary made of polytetrafluoroethylene (PTFE) or quartz glass. The capillary has an inner radius of 180 μιη and an outer radius of 350 μηι. The effective length is 2.0 cm. The filled capillary is placed in the center of the cylindrical cavity with a resonant frequency of 19 GHz. This cavity has a length of 11, 5 mm and a radius of 6 mm. Thereafter, the input signal ("source") is applied and the result of the output signal is recorded with a commercial network analyzer ("vector network analyzer"). For other frequencies, the dimensions of the cavity are adjusted accordingly.

From the change of the resonance frequency and the Q factor, between the measurement with the capillary filled with the liquid crystal and the measurement without the capillary filled with the liquid crystal, the dielectric constant and the loss angle at the corresponding target frequency are calculated by means of equations 10 and 11 of FIG previously mentioned document A. Penirschke et al, 34 ^th European Microwave Conference -. Amsterdam, pp 545-548 determined as described there.

The values for the components of the properties perpendicular to and parallel to the director of the liquid crystal are obtained by orienting the liquid crystal in a magnetic field. For this purpose, the magnetic field of a permanent magnet is used. The strength of the magnetic field is 0.35 Tesla. The orientation of the magnet is adjusted accordingly and then rotated accordingly by 90 °.

The dielectric anisotropy in the μ-wave range is defined as

Δε _Γ Ξ (ε _Γ, ιι - ε _Γ, χ). The modulability or controllability ("tuneability", τ) is defined as

mit dem maximalen dielektrischen Verlustfaktor tan

The material quality (η) is defined as

with the maximum dielectric loss factor tan

, hervorgeht. der from the maximum value of the measured values for

, shows.

The material quality (η) of the preferred liquid crystal materials is 6 or more, preferably 7 or more, preferably 10 or more, preferably 15 or more, more preferably 25 or more and most preferably 30 or more.

The preferred liquid crystal materials have in the respective components phase shifts of 157 dB or more, preferably 207 dB or more, preferably 307 dB or more, preferably 407 dB or more, preferably 507 dB or more, more preferably 807 dB or more and most preferably 1007 dB or more.

The liquid-crystal media according to the invention are preferred

nematic phases of at least from -20 ° C to 80 ° C, preferably from -30 ° C to 85 ° C and most preferably from -40 ° C to 100 ° C on. Particularly preferably, the phase is up to 120 ° C or more, preferably up to 140 ° C or more, and most preferably up to 180 ° C or more. In this case, the term "nematic phase" means, on the one hand, that no smectic phase and no crystallization are observed at low temperatures at the corresponding temperature and, on the other hand, that clarification does not yet occur on heating from the nematic phase. The investigation at low temperatures is carried out in a flow viscometer at the appropriate temperature and checked by storage in test cells, with a layer thickness of 5 pm, for at least 100 hours. At high temperatures, the clearing point is measured in capillaries by conventional methods. The liquid crystal media according to the present invention preferably have a clearing point of 90 ° C or more, more preferably 100 ° C or more, even more preferably 120 ° C or more, more preferably 150 ° C or more, and most preferably 170 ° C or more, up.

The Δε of the liquid crystal medium according to the invention at 1 kHz and 20 ° C is preferably 1 or more, more preferably 2 or more, and most preferably 3 or more.

The Δη of the liquid crystal media according to the present invention is preferably 589 nm (Na ^D ) and 20 ° C in the range of 0.20 or more to 0.90 or less, more preferably in the range of 0.25 or more to 0.90 or less, more preferably in the range of 0.30 or more to 0.85 or less and most preferably in the range of 0.35 or more to 0.80 or less.

In a preferred embodiment of the present application, the Δη of the liquid crystal media according to the present invention is preferably 0.50 or more, more preferably 0.55 or more.

Furthermore, the liquid-crystal media according to the invention are characterized by high anisotropies in the microwave range. The birefringence is e.g. at about 8.3 GHz preferably 0.14 or more, more preferably 0.15 or more, more preferably 0.20 or more, more preferably 0.25 or more, and most preferably 0.30 or more. In addition, the birefringence is preferably 0.80 or less.

The liquid crystals used are either individual substances or mixtures. Preferably, they have a nematic phase.

In the present application, unless expressly stated otherwise, the term compounds means both one compound and several compounds. Preferred devices containing a liquid crystal medium or at least one compound according to the invention are phase shifters, varactors, antenna arrays (eg for radio, mobile radio, radio,

Microwaves / radar and other data transmission), matching circuit adaptive filters and others. Preference is given to components for the

High frequency technology as defined above. Preference is also given by different applied electrical voltages modulatable components. Very particularly preferred components are tunable

Phase shifter. In preferred embodiments, multiple phase shifters are operatively connected, resulting in, for example, a phased array antenna, commonly referred to as a 'phased array' antenna. A group antenna uses the

Phase shifting of the arranged in a matrix transmitting or receiving elements to achieve by bundling interference. From a row or grid-like parallel arrangement of

Phase shifters can be a so-called 'phased array' build, which can be used as a tunable or passive transmitting or receiving antenna for

High frequencies (eg Gigahertz range) can serve. Inventive 'phased array' antennas have a very wide usable

Reception cone.

Preferred applications are radar installations and

Data transmission equipment on manned or unmanned vehicles in the automotive, shipping, aircraft, space and

Satellite technology.

For the production of suitable components for high-frequency technology, in particular suitable phase shifter, a liquid-crystalline medium according to the invention is typically introduced into rectangular cavities of less than 1 mm thickness, several mm wide and several centimeters long. The cavities have opposing electrodes mounted along two long sides. Such arrangements are familiar to the skilled person. By applying a variable voltage when operating the antenna, the dielectric properties of the liquid-crystalline medium can be tuned to different

Set frequencies or directions of an antenna.

The term "halogen" or "halogenated" stands for F, Cl, Br and I, especially for F and Cl and especially for F.

The term "alkyl" preferably includes straight-chain and branched alkyl groups having 1 to 15 carbon atoms, in particular the

straight-chain groups methyl, ethyl, propyl, butyl, pentyl, hexyl and heptyl. Groups of 2 to 10 carbon atoms are generally preferred.

The term "alkenyl" preferably comprises straight-chain and branched alkenyl groups having 2 to 15 carbon atoms, in particular the straight-chain groups. Particularly preferred alkenyl groups are C ₂ to C ₇ -1 E-alkenyl, C ₄ to C ₇ -3E-alkenyl, C ₅ to C ₇ -4-alkenyl, C ₆ to C ₇ -5-alkenyl and C ₇ -6-alkenyl Alkenyl, in particular C ₂ to C ₇ -1 E-alkenyl, C to C ₇ - 3E-alkenyl and C ₅ to C ₇ -4 alkenyl. Examples of further preferred alkenyl groups are vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 1E-heptenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl, 4Z-hexenyl, 4E-hexenyl, 4Z-heptenyl, 5-hexenyl, 6-heptenyl and the like. Groups of up to 5 carbon atoms are generally preferred. The term "alkoxy" preferably includes straight-chain radicals of

Formula C _n H _2n + i-O- wherein n is 1 to 10. N is preferably 1 to 6. Preferred alkoxy groups are, for example, methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy, n-nonoxy, n-decoxy.

The term "oxaalkyl" or "alkoxyalkyl" preferably encompasses straight-chain radicals of the formula C _n H2 wherein n and m are each independently from 1 to 10 _n + i-0- _{(CH2) m.} Preferably, n is 1 and m is 1 until 6. The term "fluorinated alkyl" preferably includes mono- or polyfluorinated radicals. Perfluorinated radicals are included.

Particular preference is given to CF _3l CH ₂ CF ₃ , CH ₂ CHF ₂ , CHF _2l CH ₂ F, CHFCF ₃ and CF ₂ CHFCF ₃ .

The term "fluorinated alkoxy" includes mono- or polyfluorinated radicals. Perfluorinated radicals are preferred. Particularly preferred is the radical OCF ₃ . The term "alk (en / yn) yl groups, wherein one or more" - CH ₂ - "-

Groups preferably substituted by -O- "refers to those groups in which a non-terminal CH ₂ group is replaced OH groups are included in the general meaning with The term" substituted cycloalkyl "includes one or more times alkyl-substituted cycloalkyl, especially alkyl of 1 to 8

Carbon atoms.

The term "substituted phenyl" includes phenyl which is monosubstituted or polysubstituted by a group such as R ¹ , in particular phenyl which is substituted by F, Cl, alkyl or alkoxy.

In the present application means high frequency technology

Applications with frequencies in the range of 1 MHz to 10 THz, preferably from 1 GHz to 3 THz, more preferably 2 GHz to 1 THz, particularly preferably from 5 to 300 GHz. The application is preferably in the microwave spectrum or adjacent, for the

Message transmission suitable areas in which 'phased array' modules can be used in transmitting and receiving antennas.

The liquid-crystal media according to the invention consist of one or more compounds, preferably from 2 to 30, more preferably from 3 to 20 and most preferably from 3 to 16 compounds. These

Compounds are mixed in a conventional manner. In general, the desired amount of those used in the smaller amount

Dissolved compound in the compound used in the larger amount. If the temperature is above the clearing point of the compound used in the higher concentration, the completion of the dissolution process is particularly easy to observe. However, it is also possible to use the media in other conventional ways, for example using so-called premixes, which may for example be homologous or eutectic mixtures of compounds, or using so-called "multi-bottle" systems, whose constituents are themselves ready-to-use mixtures.

 All temperatures, e.g. the melting point T (K, N) or T (K, S), the transition from the smectic (S) to the nematic (N) phase T (S, N) and the clearing point T (N, l) of the liquid crystals are in Degrees Celsius indicated. All temperature differences are indicated in degrees of difference.

In the present application and in the following examples, the structures of the liquid crystal compounds are indicated by acronyms, wherein the transformation into chemical formulas according to following Tables A and B takes place. All radicals C _n H _2n + i and C _m H _2m + i are straight-chain

Alkyl radicals with n or m C atoms; n, m and k are integers and are preferably 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12. The coding according to Table B is self-evident. In Table A only the acronym for the main body is given. In individual cases, followed by asterisks, a code for the substituents R ^{1 *} , R ^{2 *} , L ^{1 *} and L ^{2 *} follows separately from the acronym for the main body:

Suitable mixture components are given in Tables A and B.

The following examples illustrate the present invention without limiting it in any way.

From the physical properties, however, it will be apparent to those skilled in the art which properties can be achieved and in which areas they are modifiable. In particular, therefore, the combination of the different those properties which can preferably be achieved are well defined by those skilled in the art.

In the present application, unless expressly stated otherwise, the plural form of a term means both the singular form and the plural form, and vice versa. Other combinations of

Embodiments and variants of the invention according to the description will become apparent from the appended claims.

Used abbreviations:

 MTB methyl tert-butyl ether

S1O ₂ silica gel

 RT room temperature (about 20 ° C)

Examples

The acetylenes and boronic acids used are commercially available or can be prepared analogously to known syntheses which are known to the person skilled in the art. The radicals "C4H9" stand for unbranched n-butyl radicals. The same applies to C3H7, C6H13, etc.

Synthetic Example 1:

 Synthesis of 1,4-bis (4-n-butylphenylethynyl) phthalazine

10 g (50 mmol) of 1,4-dichlorophthalazine and 18 g (114 mmol) of 4-n-butylphenylacetylene are initially charged in 250 ml of triethylamine, with 200 mg (1 mmol) of copper (I) iodide and 700 mg (1 mmol ) Added bis (triphenylphosphine) -palladium (II) chloride and refluxed for 1.5 h. The mixture is cooled, treated with water and toluene and the phases separated. The organic phase is washed once with saturated ammonium chloride solution and once with saturated sodium chloride solution, dried over sodium sulfate, filtered off and concentrated on a rotary evaporator. Of the

Residue is purified by column chromatography (S1O2, toluene -> toluene

/ Ethyl acetate = 10: 1).

 Further purification is carried out by recrystallization from toluene or toluene-heptane mixtures.

MS (El): m / z (%) = 442 (100, M ⁺ ), 414 (13), 399 (13), 328 (11), 313 (9).

Δε = -3.2

 Δη = 0.41

γι = 3475 mPa s

 K 148 N 179 I

Analogously, the following Examples 2 to 5 are synthesized:

2) 4.7-Bi - (4-n-butylphenylethvnvO-2.1.3-benzothiadiazole. (2)

MS (El): m / z (%) = 448 (100, M ⁺ ), 405 (35, [M-propyl] ⁺ ), 362 (22, [M-2-propyl] ⁺ ), 181 (10, M - 2 propyl] ²⁺ ).

Δ∈ = +1, 3

Δη = 0.48

γι = 1703 mPa-s

K 87 N 165 1 3) 4.7-bis-4-n-butyl-phenyl-phenyl) -indane

MS (El): m / z (%) = 430 (100, M ⁺ ), 387 (25, [M-propyl] ⁺ ), 344 (8, [M-2-propyl] ⁺ ), 172 (12, M - 2 propyl] ²⁺ ). Δ∈ = +1, 7

Δη = 0.42

γι = 1532 mPa-s

K 109 N 178 I

4) 5.8-bis-n-butylphenylethvnyl) -1.2.3.4-tetrahydronaphthalene

MS (El): m / z (%) = 444 (100, M ⁺ ), 401 (15, [M-propyl] ⁺ ).

Δε = +2.4

Δη = 0.39

γ, = 3238 mPa s

K 77 N 160 I

5) 5,8-bis-4-n-butylphenylethynyl) quinoline

MS (El): m / z (%) = 441 (100, M ⁺ ), 398 (40, [M-propyl] ⁺ ), 355 (20, [M-2-propyl] ⁺ ), 177.5 (13 , [M-2-propyl] ²⁺ ). Δ∈ = + 6.5

Δη = 0.44

γι = 3347 mPa s

Κ 85 Ν 152 I

6a) 3 ^' .6 ^' -Ditrifluoromethanesulfonylbenzonorbornane

4 g (22 mmol) of 3 ^' , 6 ^' -dihydroxy-benzonorbornan be in 80 ml

Submitted to dichloromethane, mixed with 15 ml (108 mmol) of triethylamine and 102 mg (0.8 mmol) of 4-dimethylamino-pyridine and cooled in an ice bath.

Then 17.5 g (61 mmol) of trifluoromethanesulfonic acid anhydride are added dropwise, and the mixture is stirred overnight while heating to RT. Subsequently, water is added carefully and the phases are separated. The organic phase is washed with water and saturated

Washed sodium bicarbonate solution, dried over sodium sulfate, filtered off and concentrated on a rotary evaporator. Of the

Residue is purified by column chromatography (S1O2, dichloromethane); the product is obtained as a yellow oil.

6b) 3 ^' , 6 -bis (4-n-butylphenylethvnyl) benzonorbornane

7.1 g (42 mmol) of 4-n-butyl-phenylacetylene are introduced into 50 ml of tetrahydrofuran, cooled to -75 ° C and 42 ml (1, 0 M in hexane, 42 mmol) Lithiumhexamethyldisilazid. After 1 h, 42 ml (1.0 M in hexane, 42 mmol) of B-methoxy-9-borabicyclo [3.3.1] nonane are added and stirred for an additional hour. Then, the formulation is heated to -20 ° C, with 500 mg (0.55 mmol) tris (dibenzylideneaceton) dipalladium, 160 mg (0.39 mmol) 2-dicyclohexylphosphino-2 ^'-6' -dimethoxybiphenyl and 8.5 g (19 mmol) of the triflate obtained in the previous reaction in 50 ml of tetrahydrofuran and refluxed for 16 h. The

Work-up is carried out by adding MTB and water, the phases are separated and the aqueous phase is extracted once with MTB. The combined organic phases become saturated

 Natriumchloridlsg. washed, dried over sodium sulfate, filtered off and concentrated on a rotary evaporator. The residue will be

purified by column chromatography (S1O2, heptane toluene = 9: 1); the product is obtained as an orange solid.

The further purification is carried out by recrystallization from isopropanol and ethanol-toluene mixtures.

MS (El): m / z (%) = 456 (100, M ⁺ ), 428 (46, [M-ethylene] *), 413 (8, [M-propyl] ⁺ ), 385 (30, [M - ethylene - propyl] ⁺ ).

Δε = +0.6

 Δη = 0.34

γι = 5504 mPa-s

 Tg -18 K 95 N 105 1

7) 2,6-bis (4-n-butylphenylethvnyl) benzthiophene (7)

MS (El): m / z (%) = 446 (100, M ⁺ ), 403 (35, [M-propyl] ⁺ ), 360 (22, [M-2-propylf), 180 (16, [M -] 2% propyl] ²⁺ ). Δε = +3.1

Δη = 0.50

γι = 1494 mPa-s

K 99 N 224 I Mixing Example 1

 A liquid crystal medium M-1 having the composition and properties as shown in the following table is prepared. The compound (2) (No. 15) is from Synthesis Example 2.

This mixture is used for microwave applications,

used in particular for phase shifters for 'phased array' antennas.

For comparison, a medium C-1 without the component (2) is prepared from the compounds Nos. 1-14 of the medium M-1, wherein the

Compounds Nos. 1-14 are contained in the same relative amounts. Mixture example 2

 A liquid-crystal medium M-2 having the composition of M-1 is prepared, except that the compound (7) of Synthesis Example 7 is used instead of the compound (2).

The results for mixture examples 1 and 2 can be found in the following table.

Table: Properties of mixtures M-1. M-2 and C-1 (comparison) at 19 GHz (20 ° C)

The controllability τ, the maximum loss factor (here tan δ _ε , _{r JL} ) and the material quality η are each significantly improved compared to the comparison mixture C-1.

Claims

claims 1. Compounds of the formula I

 wherein

wherein X is O, S, SO, SO ₂ , NH, NR ³ or NO, one or two non-adjacent -CH ₂ - may be replaced by X, and R ³ is defined as R ¹ , b) 1, 4-phenylene, wherein one or more, preferably one or two, CH groups may be replaced by N,  c) a remainder of the formulas

d) trans-1, 4-cyclohexylene or cyclohexenylene, wherein also one or two non-adjacent CH ₂ groups may be replaced by -O- and / or -S-, and in which H may be replaced by F, or  e) a radical from the group 1, 4-bicyclo (2,2,2) -octylene,  Cyclobutane-1, 3-diyl, spiro [3.3] heptane-2,6-diyl, thiophene-2,5-diyl, thiophene-2,4-diyl, furan-2, 5-diyl, furan-2,4- diyl, and in which groups a), b), c), d) and e) also one or more H atoms to Br, Cl, F, CN, -NCS, -SCN, SF ₅ , C 1 -C 10 alkyl, C 1 -C 10 alkoxy, C 3 -C 6 cycloalkyl or a mono- or polyfluorinated C 1 -C 10 alkyl or alkoxy group may be replaced, and where at least one radical from A ² , A ³ and A ^{4 represents} a radical according to a), R and R ² each independently represent a halogenated or unsubstituted alkyl radical having 1 to 15 C atoms, where in these radicals also one or more CH 2 groups are each independently of one another denoted by -CsC-, -CH =CH-, -CF =CF- , -CF = CH-, -CH = CF-, - (CO) O-, -O (CO) -, - (CO) -, -O- or -S- may be replaced so that O- or S Atoms not directly  linked together, F, Cl, Br, CN, CF _3, OCF _3, SCN, NCS or SF _5, Z ² , Z ^{3 are} independently -CsC- or

Y ¹ , Y ² independently of one another are H, F, Cl, C ¹ -C 10 -alkyl, Z ¹ , Z ⁵ independently of one another a single bond, -C = C-, -CH = CH-, -CH ₂ 0-, - (CO) O-, -CF ₂ 0-, -CF ₂ CF ₂ -, -CH ₂ CF ₂ -, -CH ₂ CH ₂ -, - (CH ₂ ) ₄ -, -CH = CF- or -CF = CF-, where asymmetric bridges may be oriented to either side, p 1 or 2, and m, n independently of one another 0, 1 or 2, or R ¹ - (A ¹ -Z ¹ ) _m -A ² - or -A ⁴ - (Z ⁵ -A ⁵ ) "- R ² independently optionally also a radical of the formulas

 mean. 2. Compounds according to claim 1, characterized in that the group A ^{3 of} the formula I is a radical according to definition a). 3. Compounds according to claim 1 or 2, characterized in that p is 1. 4. Compounds according to one or more of claims 1 to 3, characterized in that compounds of the formulas

wherein R ¹ and R ^{2 are} both CH ₃ , both F or both CF _{3 are} not included. 5. Compounds according to one or more of claims 1 to 4, characterized in that the rings A ² and A ^{4 is} an optionally substituted 1,4-phenylene ring. 6. Compounds according to one or more of claims 1 to 5, characterized in that m and n represent 0. 7. Liquid crystal medium, characterized in that it contains one or more compounds of the formula I according to one of claims 1 to 6. 8. Liquid crystal medium according to claim 7, characterized in that it additionally contains one or more compounds selected from the compounds of formula II:

in which mean: 1 1 R or X ¹ 11 ¹ , L ¹² R ¹² or X ¹² , R ¹¹ and R ^{12 are} independently of each other unfluorinated alkyl or unfluorinated alkoxy having 1 to 17 C atoms or unfluorinated alkenyl, unfluorinated alkynyl, unfluorinated alkenyloxy, or unfluorinated alkoxyalkyl having 2 to 15 C atoms, X ¹¹ and X ¹² independently of one another F, Cl, Br, -CN, -NCS, - SCN, -SF ₅ , fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, fluorinated alkenyloxy or fluorinated alkoxyalkyl having 2 to 7 C atoms, p, q independently 0 or 1, Z ¹¹ to Z ¹³ independently trans- -CH = CH-, trans- -CF = CF-, -C = C- or a single bond, and

until independently of each other

in which L is independently branched or unbranched alkyl, alkenyl or alkynyl having 1 to 12 C atoms, in which independently of one another one or more "-CH ₂ -" groups may be replaced by O, C 3 -C 6 -cycloalkyl, C 3 -C 6 -cycloalkenyl, fluorinated alkyl or alkenyl, fluorinated alkyloxy or alkenyloxy, F, Cl, Br, CN, NCS, SCN or SF ₅ , 9. A liquid crystal medium according to claim 7 or 8, characterized  characterized in that the concentration of the compounds of  Formula I in the medium ranges from 5% to 95% in total. 10. Use of the compounds of the formula I according to one of  Claims 1 to 6 in a liquid-crystalline medium. 11. Use of the compounds of the formula I according to one of  Claims 1 to 6 in a component for high-frequency technology. 12. A process for producing a liquid-crystal medium according to a  or more of claims 7 to 9, characterized in that one or more compounds of formula I with one or  several other compounds and optionally with one or  mixed several additives. 13. component for high-frequency technology, characterized in that  it is a liquid crystal medium according to one or more of  Claims 7 to 9 contains. 14. Component according to claim 13, characterized in that it is one or more functionally connected phase shifter. 15. Use of a liquid-crystal medium according to one or more of claims 7 to 9 in a component for high-frequency technology. 16. 'Phased array' antenna, characterized in that it contains one or more components according to claim 13 or 14.