TWI545180B - Compounds for a liquid-crystalline medium, and the use thereof for high-frequency components - Google Patents

Description

Compounds for liquid crystal media and their use in high frequency components

The present invention relates to a compound having at least one bicyclic or tricyclic ring system linked by an extended ethylene group or a difluoroextended ethyl bridge, which is used for high frequency components, including liquid crystal media of such compounds, and High-frequency components of such media, in particular antennas, especially for antennas in the gigahertz range. Liquid crystal media are used for, for example, microwave phase shifting of phased array antennas.

Liquid crystal media have been used in electro-optical displays (LCDs) to display information for a period of time.

A 1,4-diacetylenylbenzene derivative is proposed as a liquid crystal component in the specification EP 0 968 988 A1, DE 19907941 A1, DE 10120024 A1 and JP 08012599 A. Compounds having a (difluoro)extended ethyl bridge between the two rings are not disclosed.

However, liquid crystal media have also been proposed for use in components of microwave technology in DE 10 2004 029 429 A and JP 2005-120208 (A).

One of the industrial applications of liquid crystal media in high frequency technology is based on its properties of dielectric properties controllable by variable voltage, especially in the gigahertz range. Therefore, it is possible to design a tunable antenna without 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, paper ID 876989, 7 Page, 2009.doi:10.1155/2009/876989).

Publications A. Penirschke, S. Müller, P. Scheele, C. Weil, M. Wittek, C. Hock and R. Jakoby: "Cavity Perturbation Method for Characterization of Liquid Crystals up to 35 GHz", 34 ^th European Microwave Conference -Amsterdam, 545-548, in particular, describes the properties of the known liquid crystal individual substance K15 (Merck KGaA, Germany) at a frequency of 9 GHz.

Those skilled in the art are aware of 1-(phenylethynyl)diphenylacetylenes (hereinafter also referred to as bis-diphenylacetylene compounds) having an alkyl substituent on a central phenyl ring. For example, the publication S.-T. Wu, C.-S. Hsu, K.-F. Shyu Appl. Phys. Lett. (1999), 74(3), 344-346 discloses a side methyl group of the formula Various liquid crystal bis-diphenylacetylene compounds,

In addition to liquid crystal bis-phenylene acetylene compounds of this type having pendant methyl groups, CSHsu, KFShyu, YYChuang, S.-T. Wu Liq. Cryst. (2000), 27(2), 283-287 also disclose Corresponding compounds having pendant ethyl groups and their use, especially in "liquid crystal optical phase arrays".

DE 10 2004 029 429 A (cf. above) describes the use of conventional liquid crystal media in microwave technology, especially in phase shifters. Among them, the liquid crystal medium has been studied for its properties in the corresponding frequency range.

a compound of the formula And its derivatives are described as components of organic thin film transistors (EP 2 073 290 A1), as photosensitive dyes for controlling "photoacid generating systems" (WO 2008/021208 A2) and as components of data recording media (JP) 2004-082439 A). The properties of liquid crystals and their use in liquid crystal media have not been described so far. Furthermore, EP 2 073 290 A1 names the following compounds:

In each case, four symmetrically substituted molecules can be mentioned.

However, compositions or individual compounds known to date are generally affected by their disadvantages. Most of these lead to unfavorable high losses and/or inadequate phase shifts or insufficient material quality, among other deficiencies.

In order to be used in high frequency technology, liquid crystal media having specific, to date, rather unusual, non-standard properties or combinations of properties are required.

Therefore, there is a need for novel compositions for liquid crystal media having improved properties. In particular, it is necessary to reduce the loss in the microwave region and to improve the material quality (η). For a tunable antenna, a liquid crystal medium having a fast reaction time for a voltage change between battery electrodes is also required.

In addition, there is a need to improve the low temperature behavior of the components. Need to improve operability And storage.

Therefore, there are many requirements for liquid crystal media having suitable properties for the respective practical applications.

Surprisingly, it has been found that the compounds according to the invention have a broad nematic phase and a high clearing point (transition from a nematic phase to an isotropic phase). At the same time, the optical anisotropy (Δn) is located in a region where the phase shift of the microwave is favorable. Utilizing this effect, it has now surprisingly been found that the use of the compounds according to the invention makes it possible to achieve liquid crystal media having a suitable nematic phase range and high Δn without the disadvantages of prior art materials or at least to a significant extent. .

The present invention relates to a compound of formula I, Wherein A ^1-5 independently of each other represents a group of a) Wherein X represents O, S, SO, SO ₂ , NH, NR ³ or NO, one or two are unconnected -CH ₂ - may be substituted by X, and R ³ is as defined by R ¹ , b) 1,4- a phenyl group, wherein one or more, preferably one or two CH groups may be substituted by N, c) a group of the formula d) trans-1,4-cyclohexylene or cyclohexenylene, in which one or two unconnected CH ₂ may be substituted by -O- and/or -S-, and wherein H may be substituted by F Or e) selected from the group consisting of 1,4-bicyclo[2.2.2] octyl, cyclobutane-1,3-diyl, spiro[3.3]heptane-2,6-diyl, thiophene- a group of 2,5-diyl, thiophene-2,4-diyl, furan-2,5-diyl, furan-2,4-diyl, and wherein, in groups a), b), c In, d) and e), one or more H atoms may also pass through Br, Cl, F, CN, -NCS, -SCN, SF ₅ , C ₁ -C ₁₀ alkyl, C ₁ -C ₁₀ alkoxy a C ₃ -C ₆ cycloalkyl group or a mono or polyfluorinated C ₁ -C ₁₀ alkyl or alkoxy group, and at least one of the groups derived from A ² , A ³ and A ⁴ is represented by a) a group wherein R ¹ and R ² each independently represent a halogenated or unsubstituted alkyl group having 1 to 15 carbon atoms, and wherein one or more CH ₂ groups of such a group may be respectively Independently from each other, -C≡C-, -CH=CH-, -CF=CF-, -CF=CH-, -CH=CF-, -(CO) are such that the O or S atoms are not directly connected to each other. Substituted by O-, -O(CO)-, -(CO)-, -O- or -S-, F, Cl, Br, CN, CF ₃ , OCF ₃ , SCN, N CS or SF ₅ , Z ² , Z ³ independently of each other -C≡C- or , Y ¹ and Y ² independently of each other represent H, F, Cl, C ₁ -C ₁₀ alkyl, preferably H or F, particularly preferably F, Z ¹ , Z ⁵ independently of each other represent 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-, wherein the asymmetric bridge can be oriented to both sides, p represents 1 or 2, and m, n independently represent 0, 1 or 2, Or R ¹ -(A ¹ -Z ¹ ) _m -A ² - or -A ⁴ -(Z ⁵ -A ⁵ ) _n -R ² may independently represent a group of the following formula as needed

Preferred compounds of formula I are those of the formula

It does not include that both R ¹ and R ² represent CH ₃ , and both represent F or both represent CF ₃ .

The double bond of the formula -CY ¹ =CY ² - between the rings A ² to A ⁴ and the optional double bonds in the groups Z ¹ and Z ⁵ preferably have a trans configuration (E configuration) .

The compound according to the invention has a high clearing point, a low melting point and a high optical anisotropy (Δn). The rotation of the undesired compound is limited, meaning that it is particularly suitable for use in the gigahertz range. Lower loss factors in the microwave spectrum are advantageous. Compounds, either alone or in combination with other liquid crystal primordial components, have a nematic phase over a wide range of temperatures. This property makes it particularly suitable for use in components of high frequency technology, in particular for liquid crystal phase shifters. The liquid crystal medium according to the invention has corresponding properties.

Preferred compounds of formula I are characterized by the choice of one or more of the following parameters: the index m is preferably 0 or 1, especially preferably 0. The index n is preferably 0 or 1, especially preferably 0. m+n is preferably 0 or 1 and particularly preferably 0. m+n+p is preferably 1 or 2, i.e., the total number of ring systems in Formula I is preferably 3 or 4.

According to definition a), the groups A ² , A ³ and A ⁴ preferably together comprise one or two bicyclic or tricyclic groups. According to the definition a), the group A ³ particularly preferably represents a ring group. According to the definition b) or c), the cyclic groups A ² and A ⁴ and the optionally present A ¹ and A ⁵ particularly preferably independently represent optionally substituted cyclic groups, in particular 1,4-substituted Stretch phenyl.

The bridging groups Z ¹ and Z ⁵ preferably independently of each other represent a single bond, -C≡C-, -CF=CF- or -CH=CH-, particularly preferably a single bond.

Z ² and Z ^{3 are} preferably -C≡C- or -CF=CF-, particularly preferably -C≡C-. Such groups are particularly advantageous for high Δn values and excellent phase properties.

Y ¹ /Y ^{2 is} preferably H/F, F/H, F/F, Cl/F, CH ₃ /F, F/CH ₃ or F/Cl and particularly preferred F/F.

One or both of the groups R ¹ or R ² , preferably R ¹ , preferably represents a linear alkyl group having from 1 to 15, in particular 2 to 15 carbon atoms, in addition, such One or more CH ₂ groups in the group may be independently of each other via -C≡C-, -CH=CH-, -(CO)O-, -O (in such a manner that the O atoms are not directly connected to each other). CO)-, -(CO)-, -O- are substituted. The groups R ¹ and R ^{2 are} particularly preferably all alkyl groups having 2 to 7 carbon atoms. Here, R ¹ and R ² represent, for example, a propyl group and a hexyl group, a butyl group and a butyl group, and further, a propyl group, a pentyl group, a propyl group and a hexyl group, or a butyl group and a pentyl group.

In another preferred embodiment of the invention, the group R ² is a polar group (group X). Here, the group R ² =X represents F, Cl, Br, CN, CF ₃ , OCF ₃ , SCN, NCS, SF ₅ or another halogenated alkyl group having 1 to 9 carbon atoms, and further, the group One or more CH ₂ groups in the group may be independently of each other such that -O SC-, -CH=CH-, -CF=CF-, -CF= are such that the O or S atoms are not directly connected to each other. CH-, -CH=CF-, -(CO)O-, -O(CO)-, -(CO)-, -O- or -S- are substituted. Here, R ² particularly preferably represents F, CF ₃ or OCF ₃ . The corresponding compound of formula I has a significantly positive dielectric anisotropy (Δε). The value of Δε is preferably 3 or more.

The groups R ^{2 of} the two examples thus preferably together represent an alkyl group having 2 to 15 carbon atoms, and wherein one or more of the CH ₂ groups of such groups may be independently of each other, Substituting -C≡C-, -CH=CH-, -(CO)O-, -O(CO)-, -(CO)-, -O-, or indicating that the O atoms are not directly connected to each other F, Cl, Br, CN, CF ₃ , OCF ₃ , SCN, NCS, SF ₅ or a halogenated alkyl group having 1 to 9 carbon atoms, in which one or more CH ₂ groups in the group are respectively Independently from each other, -C≡C-, -CH=CH-, -CF=CF-, -CF=CH-, -CH=CF-, -(CO) in such a manner that the O or S atoms are not directly connected to each other ) O-, -O(CO)-, -(CO)-, -O- or -S-.

According to definition b), the ring group preferably has a substructure

The preferred embodiment of the invention is thus represented by the following illustrative structure:

Wherein the group is as defined in formula I, in particular R ¹ and R ² independently represent an alkyl group having 2 to 7 carbon atoms, for example one group means propyl and the other group means hexyl or two The group also means propyl, butyl, pentyl or hexyl.

The compound of formula I is preferably prepared in the manner indicated by the illustrative synthetic reaction schemes below (reaction schemes 1 and 2). The symmetrical compound of formula I can be prepared by a single Sonogashira reaction (reaction Figure 1): Reaction Scheme 1: Scheme for the synthesis of the compounds of Formula I.

The asymmetric compound of formula (I) can be prepared in a similar manner to the reaction sequence depicted in Figure 2 of the reaction: Reaction Scheme 2: Synthesis reaction scheme for the preparation of asymmetrical compounds of formula I.

R ^1/2 in the reaction schemes 1 and 2 has the meaning of R ^1/2 as defined for the formula I. Reaction Schemes 1 and 2 show the synthesis of certain compounds. Phenyl "R ¹ - phenyl" and "R ² - phenyl" herein may be any -A ² summarize the desired groups according to formula ^{I - (Z 1 -A 1)} m -R 1 and -A ^4- (Z ⁵ -A ⁵ ) _n -R ² . The parameters R ^1/2 , A ^1-5 , Z ^1/5 , m and n are as defined above and below.

The liquid-crystalline medium according to the invention comprises one or more compounds of the formula I and, if desired, at least one other, preferably liquid crystalline, primordial compound. The liquid crystal medium thus preferably comprises two or more compounds which are preferably liquid crystals. Preferred media include the preferred compounds of formula I.

The other components of the liquid crystal medium are preferably selected from the compounds of formula II: Wherein L ¹¹ represents R ¹¹ or X ¹¹ , L ¹² represents R ¹² or X ¹² , and R ¹¹ and R ¹² independently of each other represent a non-fluorinated alkyl group having 1 to 17, preferably 3 to 10 carbon atoms or Non-fluorinated alkoxy group, or non-fluorinated alkenyl group having 2 to 15, preferably 3 to 10 carbon atoms, non-fluorinated alkynyl group, non-fluorinated alkenyloxy group or non-fluorinated alkoxy group Alkyl groups, X ¹¹ and X ¹² independently of each other represent F, Cl, Br, -CN, -NCS, -SCN, -SF ₅ , a fluorinated alkyl group having 1 to 7 carbon atoms or a fluorinated alkoxy group or Fluorinated alkenyl, fluorinated alkenyloxy or fluorinated alkoxyalkyl having 2 to 7 carbon atoms, preferably fluorinated alkoxy, fluorinated alkenyloxy, F or Cl, p, q independent The ground represents 0 or 1, and Z ¹¹ to Z ¹³ independently of each other represent trans-CH=CH-, trans-CF=CF-, -C≡C- or a single bond, and Express independently of each other Wherein L independently represents a branched or unbranched alkyl, alkenyl or alkynyl group having 1 to 12 carbon atoms, wherein one or more "-CH ₂ -" groups may also independently pass through O substituted, or represents C ₃ -C ₆ cycloalkyl, C ₃ -C ₆ cycloalkenyl group, a fluorinated alkyl or alkenyl group, an alkoxy group or a fluorinated alkylene group, F, Cl, Br, CN , NCS, SCN or SF ₅ .

In a preferred embodiment of the invention, the liquid crystal medium comprises one or more compounds of formula I and one or more compounds of formula II.

The liquid crystal medium according to the present application preferably comprises a total of 5 to 95%, preferably 10 to 90% and particularly preferably 15 to 80% of the compound of the formula I.

The liquid-crystalline medium according to the invention preferably comprises a compound selected from the group of compounds of the formulae I and II, and more preferably consists essentially of it, in particular better consisting essentially of it and, optimally, completely Its composition.

In the application, "including" in relation to a composition means that the subject (i.e., medium or component) comprises a total concentration of 10% or more, and preferably 20% or more, in an excellent manner. Refers to a component or compound.

Related to this, "mainly composed of" means that the relevant subject includes 55% or more, preferably 60% or more, and 70% or more of the best words. Component or compound.

In connection with this, "substantially composed of" means that the relevant subject comprises 80% or more, preferably 90% or more, and preferably 95% or more of the indicated components or compounds.

In connection with this, "completely composed of" means that the subject comprises 98% or more, preferably 99% or more, and 100.0% of the indicated components or compounds.

The liquid crystal medium according to the present application preferably comprises a total of 10 to 100%, preferably 20 to 95% and particularly preferably 25 to 90% of the compounds of the formulae I and II.

According to the invention, the compound of formula II is preferably from 10% to 90%, more preferably from 15% to 85%, especially more preferably from 25% to 80%, and most preferably from 30% to 75% of the total mixture. The total concentration is used.

In addition, the liquid crystal medium can include other additives such as stabilizers, palmitic dopants, and nanoparticles. These individually added compounds are used at a concentration of from 0.005 to 6%, preferably from 0.1 to 3%. The total concentration of such other ingredients in the total mixture is in the range of from 0% to 10%, preferably from 0.1% to 6%. However, the concentration data of the remaining components of the liquid crystal mixture (i.e., liquid crystal or liquid crystal primordial compound) is expressed irrespective of the concentration of such additives.

The liquid crystal medium preferably comprises from 0 to 10% by weight, in particular from 0.01 to 5% by weight and particularly preferably from 0.1 to 3% by weight of stabilizer. The medium preferably comprises one or more stabilizers selected from the group consisting of 2,6-di-t-butylphenol, 2,2,6,6-tetramethylpiperidine or 2-benzotriazol-2-ylphenol. Agent. Such adjuvants are known to those skilled in the art and are commercially available, for example, as light stabilizers.

An embodiment of the invention is thus also a method of preparing a liquid crystal medium, It is characterized in that one or more compounds of the formula I are admixed with one or more other compounds and optionally with one or more additives. These other compounds are preferably selected from the compounds of formula II above and optionally selected from one or more other compounds.

In the present application, the expression positively describes the compound or component in which Δ ε > 3.0, and the dielectric neutral description of -1.5 △ε 3.0 and their dielectric negative descriptions of Δε<-1.5 of them. The dielectric anisotropy of each compound was determined as a result of dissolving the individual compounds in a 10% solution of the nematic main mixture. If the solubility of each compound in the main mixture is less than 10%, the concentration is reduced to 5%. The capacitance of the test mixture was determined in a battery with a vertical alignment and a battery with parallel alignment. The battery thickness of both types of batteries is about 20 μm. The applied voltage is a rectangular wave having an effective value of 1 kHz and, in general, 0.5 V to 1.0 V, but it is always chosen to be lower than the capacitance threshold of each test mixture.

Δε is defined as (ε _|| -ε _⊥ ), and ε is _averaged as (ε _|| +2 ε _⊥ )/3.

The master mix for the dielectric positive compounds was the mixture ZLI-4792 and the dielectric neutral and dielectric negative compounds were mixtures ZLI-3086, both available from Merck KGaA, Germany. The absolute value of the dielectric constant of a compound is determined by the change in each value of the main mixture upon addition of the compound of interest. This type of value can be extrapolated to the concentration of 100% of the compound of interest.

The components having a nematic phase at a measured temperature of 20 ° C were measured as such, and all others were treated as a compound.

In the present application, the term threshold voltage means optical threshold and reference is 10% relative contrast (V ₁₀ ), and the term saturation voltage means optical saturation and reference is 90% relative contrast (V ₉₀ ), in both Except as otherwise expressly stated in the circumstances. If explicitly mentioned, only the capacitor threshold voltage (V ₀ ) (also known as the Freedericks threshold (V _Fr )) is used.

Unless otherwise expressly stated, the range of parameters indicated in this application includes limits.

Combinations of different upper and lower limits indicated for each range of properties may result in other preferred ranges.

Unless otherwise expressly stated, the following conditions and definitions apply throughout the application. Unless otherwise specifically stated, all concentrations are quoted in weight percent and are related to the respective total mixture, all temperatures are quoted in degrees Celsius and all temperature differences are quoted by differential. All physical properties typical for liquid crystals were determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals", status Nov. 1997, Merck KGaA, Germany and quoted at a temperature of 20 °C. Optical anisotropy (Δn) was measured at a wavelength of 589.3 nm. The dielectric anisotropy (Δε) was measured at a frequency of 1 kHz. The threshold voltage and all other electro-optical properties were determined using a test cell manufactured at Merck KGaA, Germany. The test cell used to determine Δε had a cell thickness of about 20 μm. The electrode was a circular ITO electrode having an area of 1.13 cm ² and a guard ring. The alignment layer is SE-1211 from Nissan Chemicals, Japan for vertical orientation (ε _|| ), and poly-imine AL-1054 from Japan Synthetic Rubber, Japan for parallel orientation (ε _⊥ ) . The capacitance was measured at a voltage of 0.3 V _rms using a Solatron 1260 frequency response analyzer using a sine wave. The light used in electro-optical measurements is white light. Applications using commercially available DMS instruments from Autronic-Melchers are used herein. The characteristic voltage was measured under vertical observation. Threshold voltage (V _10), an intermediate gray voltage (V ₅₀₎ and saturation voltage (V ₉₀₎ lines for respectively 10%, 50% and 90% relative contrast is determined.

As A.Penirschke et al., 'Cavity Perturbation Method for Characterization of Liquid Crystals up to 35 GHz ^{", 34 th European Microwave Conference-Amsterdam} , in the 548 to 545, in the study of its properties in the microwave frequency range In terms of liquid crystal media. In contrast, there are also A. Gaebler et al., "Direct Simulation of Material Permittivities...", 12MTC 2009-International Instrumentation and Measurement Technology Conference, Singapore, 2009 (IEEE), pages 463 to 467, and DE. 10 2004 029 429 A, in which the measurement method is also detailed.

The liquid crystal can be introduced into a polytetrafluoroethylene (PTFE) or quartz capillary. The capillary has an internal radius of 180 μm and an external radius of 350 μm. The effective length is 2.0 cm. The filled capillary is introduced into the center of a cylindrical cavity having a resonant frequency of 19 GHz. The cavity has a length of 11.5 mm and a radius of 6 mm. The input signal (source) is then applied and the output signal result is recorded using a commercially available vector network analyzer. For other frequencies, the size of the cavity can be adjusted accordingly.

And a resonance frequency by the above publication A.Penirschke et al., 34 ^th European Microwave Conference-Amsterdam measurement value using a capillary of the capillary is filled with liquid crystal of the liquid crystal is filled without change of the Q-factor between the value it can be used Equations 10 and 11 described on pages 545 to 548 measure the dielectric constant and angular loss at the respective target frequencies.

The values of the properties of the members used for the directors perpendicular and parallel to the liquid crystal are obtained by the alignment of the liquid crystals in the magnetic field. For this purpose, a magnetic field with permanent magnets is used. The magnetic field strength is 0.35 Tesla. The alignment of the magnets can be adjusted accordingly and subsequently rotated by 90°.

The dielectric anisotropy in the microwave region is defined as Δε _r ≡(ε _{r, ||} - ε _{r, ⊥} ).

The modulatability or tunability (τ) is defined as τ ≡ (Δε _r / ε _{r, ||} ).

The material quality (η) is defined as η≡(τ/tan δ _{ε r,max.} ), where the maximum dielectric loss factor tan δ _{ε r,max.} :tan δ _{ε r,Max.} ≡Max.{tan δ _{ε r, ⊥} ; tan δ _{ε r, ||} } which is the maximum value of the measured value of tan δ _ε .

Preferably, the material quality (η) of the liquid crystal material is 6 or more, preferably 7 or more, preferably 10 or more, preferably 15 or more, particularly preferably 25 or more. Big and excellent 30 or more.

Preferably, in the corresponding member, the liquid crystal material has 15°/dB or more, preferably 20°/dB or more, preferably 30°/dB or more, preferably 40°/dB. A phase shifter quality of greater or better, preferably 50°/dB or greater, particularly preferably 80°/dB or greater, and excellently 100°/dB or greater.

The liquid crystal medium according to the invention preferably has at least -20 ° C to 80 ° C, preferably -30 ° C to 85 ° C and, optimally -40 ° C to 100 ° C in each case. Nematic phase. This phase is particularly preferably increased to 120 ° C or more, preferably to 140 ° C or more, and extremely preferably to 180 ° C or more. This expression has a nematic phase as shown here: on the one hand, no smectic phase and crystallization are observed at low temperatures at the respective temperatures and, on the other hand, no phase change occurs in the nematic phase upon heating. The studies at low temperatures were carried out in a flow viscometer at the corresponding temperature and examined by storage in a test cell having a cell thickness of 5 μm for at least 100 hours. At elevated temperatures, the clarification point is measured in a capillary by conventional methods.

The liquid crystal medium according to the present invention preferably has a temperature of 90 ° C or more, more preferably 100 ° C or more, particularly preferably 120 ° C or more, particularly preferably 150 ° C or more, and preferably 170 ° C or more. Clarification point.

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

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

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

Moreover, the liquid crystal medium according to the present invention is characterized by high anisotropy in the microwave region. For example, the birefringence is preferably 0.14 or more at about 8.3 GHz, particularly preferably 0.15 or more, particularly preferably 0.20 or more, particularly preferably 0.25 or more, and excellently 0.30 or more. In addition, the birefringence is preferably 0.80 or smaller.

The liquid crystals used are individual substances or mixtures. It preferably has a nematic phase.

In the present application, the term compound means a compound or a plurality of compounds unless explicitly stated otherwise.

Preferred components including the liquid crystal medium or at least one compound according to the present invention are phase shifters, varactors, antenna arrays (for example, for frequency modulation, cell phone communication, microwave/radar, and other data transmitters), "matching circuits" Adaptive Filter" and others. It is preferably a member for high frequency technology as defined above. It is preferably also a member that can be adjusted by different applied voltages. An excellent component is an adjustable phase shifter. In the preferred embodiment, a plurality of phase shifters are functionally coupled to produce, for example, phased group antennas (generally referred to as "phase array" antennas). A set of antennas uses a phase shift of the transmission or receiving elements in a matrix configuration to effect bundling through interference. The parallel structure of the phase shifters in the form of a grid or column can be constructed as a "phase array" that can serve as an adjustable or passive transmission or receiving antenna for high frequencies (e.g., in the gigahertz range). The phased array antenna according to the present invention has a widely available receiving light cone.

Preferred applications are radar devices and data transmission equipment for manpower operated or unmanned tools in the automotive, marine, aircraft, spacecraft, and satellite technology fields.

To produce suitable components for high frequency technology, in particular suitable phase shifters, liquid crystal media according to the present invention are typically introduced into rectangular cavities having a thickness of less than 1 mm, a width of a few millimeters, and a length of a few centimeters. The cavity has opposing electrodes mounted along the two long sides. Those skilled in the art are aware of this type of knot Structure. By applying a variable voltage, the dielectric properties of the liquid crystal medium can be adjusted during antenna operation to set different frequencies or directions of the antenna.

The term "halogen" or "halogenated" means F, Cl, Br and I, especially F and Cl and, in particular, F.

The term "alkyl" preferably encompasses straight-chain and branched alkyl groups having from 1 to 15 carbon atoms, in particular straight-chain groups, methyl, ethyl, propyl, butyl, pentyl and hexyl. A group having 2 to 10 carbon atoms is generally preferred.

The term "alkenyl" preferably encompasses straight-chain and branched alkenyl groups having from 2 to 15 carbon atoms, in particular straight-chain groups. Particularly preferred alkenyl groups are C ₂ - to C ₇ -1E-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, specifically C ₂ - to C ₇ -1E-alkenyl, C ₄ - to C ₇ -3E-alkenyl and C ₅ - to C ₇ -4-alkenyl. Examples of other alkenyl groups are ethenyl, 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 having up to 5 carbon atoms are generally preferred.

The term "alkoxy" preferably encompasses a straight-chain group having the formula C _n H _2n+1 -O-, wherein n represents from 1 to 10. n is preferably from 1 to 6. Preferred alkoxy groups are, for example, methoxy, ethoxy, n-propoxy, n-butoxy, n-pentyloxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-decyloxy, positive Alkoxy.

The term "oxaalkyl" or "alkoxyalkyl" preferably encompasses a straight-chain group of the formula C _n H _2n +1-O-(CH ₂ ) _m wherein n and m are each independently represented 1 to 10. Preferably, n is 1 and m is 1 to 6.

The term "fluorinated alkyl" preferably encompasses mono- or polyfluorinated groups. Includes perfluorinated groups. Particularly preferred are CF ₃ , CH ₂ CF ₃ , CH ₂ CHF ₂ , CHF ₂ , CH ₂ F, CHFCF ₃ and CF ₂ CHFCF ₃ .

The term "fluorinated alkoxy" encompasses mono- or polyfluorinated groups. Includes perfluorinated groups. Particularly good is the OCF ₃ group.

The expression "an alkyl group (alkenyl/alkynyl group) in which one or more "-CH ₂ -" groups may be substituted by -O-" preferably means a group of the type in which the non-terminal CH ₂ group is substituted. group. OH groups are incorporated in the general sense.

The term "substituted cycloalkyl" encompasses a cycloalkyl group which is mono- or polysubstituted by an alkyl group (specifically, an alkyl group having from 1 to 8 carbon atoms).

The substituent term "substituted phenyl of" encompass substituted as the definition of ^a single group or a phenyl group of R, particular words by F, Cl, an alkyl or alkoxy group.

In the present application, high frequency technology means having a frequency in the range of 1 MHz to 10 THz, preferably 1 GHz to 3 THz, more preferably 2 GHz to 1 THz, particularly preferably 5 to 300 GHz. application. The application is preferably located in a microwave spectrum or adjacent area suitable for message transmission, wherein the phase array module can be used to transmit or receive an antenna.

The liquid crystal medium according to the present invention is composed of one or more compounds, preferably 2 to 30, more preferably 3 to 20, and excellently 3 to 16 compounds. Such compounds are mixed in a conventional manner. In general, the required amount of the compound to be used in a smaller amount is dissolved in the compound used in a larger amount. If the temperature is higher than the clearing point of the compound used at a higher concentration, the completion of the dissolution process is particularly easy to observe. However, it can also be made in other conventional ways. The preparation medium, for example, utilizes a so-called pre-formed mixture, which may be, for example, a homologous or eutectic mixture of the compounds, or a so-called "multi-bottle" system, the ingredients themselves being a standby mixture.

All temperatures of the liquid crystal, such as the melting point T(C,N) or T(C,S), from the smectic (S) phase to the nematic (N) phase T(S,N) and the clarification point T(N,I ), quoted in degrees Celsius. All temperature differences are quoted by differential.

In the present application and the following examples, the structure of the liquid crystal compound is indicated by an acronym, wherein the conversion of the chemical formula is carried out according to the following Tables A and B. All groups C _n H _2n+1 and C _m H _2m+1 are linear alkyl groups having n and m carbon atoms, respectively; n, m and k are integers and preferably represent 0, 1, 2, 3 , 4, 5, 6, 7, 8, 9, 10, 11 or 12. The code in Table B is self-explanatory. In Table A, only the acronyms for the parent structure are indicated. In each case, the acronym for the parent structure is separated by a dash after the codes for the substituents R ^1* , R ^2* , L ^{1* ,} and L ^2* :

Suitable mixture components are listed in Tables A and B.

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

However, those skilled in the art will understand what properties can be achieved from physical properties and to what extent they can be adjusted. In particular, combinations of various properties that are preferably achieved are thus apparent to those skilled in the art.

In the present application, the plural forms of the terms may mean both singular and plural, and vice versa, unless otherwise explicitly stated. Other combinations of the embodiments and variations of the invention according to the description are also derived from the scope of the accompanying claims.

Abbreviation used: MTB methyl tert-butyl ether

Instance

The acetylene and boric acid used are either commercially available or can be prepared in a manner similar to known synthetic methods known to those skilled in the art. The group "C ₄ H ₉ " represents an unbranched n-butyl group. The same applies to C ₃ H ₇ , C ₆ H ₁₃ and the like.

Synthesis example 1 Synthesis of 1,4-bis-(4-n-butylphenylethynyl)pyridazine

10 g (50 mmol) of 1,4-dichloropyridazine and 18 g (114 mmol) of 4-n-butylphenylacetylene were first introduced into 250 mL of triethylamine, and 200 mg (1 mmol) of copper iodide (20 mg) was added. I) and 700 mg (1 mmol) of bis(triphenylphosphine)palladium(II) chloride, and the mixture was refluxed for 1.5 h. The batch was cooled, water and toluene were added, and the phases were separated. The organic phase was washed once with saturated ammonium chloride solution and once with saturated sodium chloride solution, dried over sodium sulfate, filtered and evaporated in a rotary evaporator. The residue was purified by column chromatography (SiO ₂ , toluene toluene / ethyl acetate = 10:1).

Further purification is carried out by recrystallization from a toluene or toluene/heptane mixture.

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

△ ε = -3.2

△n=0.41

γ ₁ = 3475 mPa. s

C 148 N 179 I

The following Examples 2 to 5 were synthesized in a similar manner:

2) 4,7-bis-(4-n-butylphenylethynyl)-2,1,3-benzothiadiazole (2)

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

△ ε = +1, 3

△n=0.48

γ ₁ =1703 mPa. s

C 87 N 165 I

3) 4,7-bis-(4-n-butylphenylethynyl)-indan

MS (EI): m / e (%) = 430 (100, M ⁺ ), 387 (25, [M-propyl] ⁺ ), 344 (8, [M-2 propyl] ⁺ ), 172 (12 , [M-2 propyl] ²⁺ ).

△ ε = +1.7

△n=0.42

γ ₁ =1532 mPa. s

C 109 N 178 I

4) 5,8-bis-(4-n-butylphenylethynyl)-1,2,3,4-tetrahydronaphthalene

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

△ ε = +2.4

△n=0.39

γ ₁ = 3238 mPa. s

C 77 N 160 I

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

MS (EI): m / e (%) = 441 (100, M ⁺ ), 398 (40, [M-propyl] ⁺ ), 355 (20, [M-2 propyl] ⁺ ), 177.5 (13 , [M-2 propyl] ²⁺ ).

△ ε = +6.5

△n=0.44

γ ₁ = 3347 mPa. s

C 85 N 152 I

6a) 3',6'-Ditrifluoromethanexanthylbenzoborane

4 g (22 mmol) of 3',6'-dihydroxybenzoborane was first introduced into 80 mL of dichloromethane, and 15 mL (108 mmol) of triethylamine and 102 mg (0.8 mmol) of 4-dimethyl group were added. Aminopyridine, and the mixture was cooled in an ice bath. Then, 17.5 g (61 mmol) of trifluoromethanesulfonic anhydride was added dropwise and the batch was stirred overnight, during which time the temperature was raised to RT. Then carefully add water and phase separation. The organic phase was washed with water and a saturated aqueous solution of sodium bicarbonate, dried over sodium sulfate, filtered and evaporated on a rotary evaporator. Based residue by column chromatography (SiO _2, dichloromethane) to yield the product as a yellow oil.

6b) 3',6'-bis-(4-n-butylphenylethynyl)benzoborane

7.1 g (42 mmol) of 4-n-butylphenylacetylene was first introduced into 50 mL of tetrahydrofuran, the mixture was cooled to -75 ° C, and 42 mL (1.0 M hexane solution, 42 mmol) of hexamethyldifluoride was added. Lithium nitride. After 1 h, 42 mL (1.0 M in hexanes, &lt;RTI ID=0.0&gt;&gt; The batch was then warmed to -20 ° C and 500 mg (0.55 mmol) of tris(dibenzylideneacetone)dipalladium, 160 mg (0.39 mmol) 2-dicyclohexylphosphino group were added in 50 mL of tetrahydrofuran. 2',6'-dimethoxydiphenyl and 8.5 g (19 mmol) of triflate obtained in the previous reaction, and the mixture was refluxed for 16 h. The treatment was carried out by adding MTB and water, phase separation, and the aqueous phase was extracted once by MTB. The combined organic phases were washed with a saturated sodium chloride solution, dried over sodium sulfate, filtered and evaporated on a rotary evaporator. Based residue by column chromatography (SiO _2, heptane / toluene = 9: 1) to give the product as an orange solids.

Further purification was carried out by recrystallization from a mixture of isopropanol and ethanol/toluene.

MS (EI): m / e (%) = 456 (100, M ⁺ ), 428 (46, [M-extended ethyl] ⁺ ), 413 (8, [M-propyl] ⁺ ), 385 (30) , [M-Extended Ethyl-propyl] ⁺ ).

△ ε = +0.6

△n=0.34

γ ₁ =5504 mPa. s

Tg-18 C 95 N 105 I

7) 2,6-bis-(4-n-butylphenylethynyl)benzothiophene (7)

MS (EI): m / e (%) = 446 (100, M ⁺ ), 403 (35, [M-propyl] ⁺ ), 360 (22, [M-2 propyl] ⁺ ), 180 (16) , [M-2 propyl] ²⁺ ).

△ ε = +3.1

△n=0.50

γ ₁ =1494 mPa. s

C 99 N 224 I

Mixture example 1

A liquid crystal medium M-1 having the composition and properties as indicated in the following table was prepared. Compound (2) (No. 15) was derived from Synthesis Example 2.

This mixture is used in applications in the microwave range, in particular for phase shifters of phased array antennas.

For comparison, the medium C-1 containing no component (2) was prepared from the compound Nos. 1 to 14 of the medium M-1, wherein the compounds Nos. 1 to 14 were present in the same relative amounts.

Mixture example 2

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

The results of mixtures Examples 1 and 2 are listed in the table below:

Compared to the control mixture C-1, the tunability τ, the maximum loss factor (here, tan δ _{ε, r, ⊥} ) and the material quality η were significantly improved, respectively.

Claims (16)

a compound of formula I, Wherein A ^1-5 are oriented independently of each other and represent a) a group of the formula Wherein X represents O, S, SO, SO ₂ , NH, NR ³ or NO, one or two are not adjacent -CH ₂ - may be substituted by X, and R ³ is as defined by R ¹ , b) 1,4 - a phenyl group in which one or two CH groups may be substituted by N, c) a group of the formula d) trans-1,4-cyclohexylene or cyclohexenyl, wherein, additionally, one or two non-adjacent CH ₂ groups may be substituted by -O- and/or -S-, and wherein H Can be substituted by F, or e) selected from 1,4-bicyclo[2.2.2] octyl, cyclobutane-1,3-diyl, spiro[3.3]heptane-2,6-diyl, a group of a group of thiophene-2,5-diyl, thiophene-2,4-diyl, furan-2,5-diyl, furan-2,4-diyl, and wherein, in a), b) In groups of c, d) and e), one or more H atoms may also be through Br, Cl, F, CN, -NCS, -SCN, SF ₅ , C ₁ -C ₁₀ alkyl, C ₁ - C ₁₀ alkoxy, C ₃ -C ₆ cycloalkyl or mono or polyfluorinated C ₁ -C ₁₀ alkyl or alkoxy substituted, and at least one of the groups derived from A ² , A ³ and A ⁴ According to the group of a), R ¹ and R ² each independently represent a halogenated or unsubstituted alkyl group having 1 to 15 carbon atoms, and further, one or more CH ₂ groups of such a group. The groups may be independently of each other by -C≡C-, -CH=CH-, -CF=CF-, -CF=CH-, -CH=CF-, - in such a manner that the O or S atoms are not directly connected to each other. Substituted by (CO)- or -S-, F, Cl, Br, CN, CF ₃ , OCF ₃ , SCN, NCS or SF ₅ , Z ² , Z ³ independently of each other -C≡C- or , Y ¹ and Y ² independently of each other represent H, F, Cl, C ₁ -C ₁₀ alkyl, and Z ¹ and Z ⁵ independently of each other represent 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-, wherein the asymmetric bridge can be oriented to both sides, p represents 1 or 2, and m, n independently of each other represent 0, 1 or 2, or R ¹ -(A ¹ -Z ¹ ) _m - A ² - or -A ⁴ -(Z ⁵ -A ⁵ ) _n -R ² may independently represent a group of the following formula as needed The compound of claim 1, wherein the group A ^{3 of} formula I represents a group according to definition a). A compound of claim 1 or 2 wherein p is 1. The compound of claim 1 or 2, wherein the compound is a compound of the formula It does not include that both R ¹ and R ² represent CH ₃ , and both represent F or both represent CF ₃ . The compound of claim 1 or 2, wherein the rings A ² and A ⁴ represent an optionally substituted 1,4-phenylene ring. A compound according to claim 1 or 2, wherein m and n represent 0. A liquid crystal medium comprising one or more compounds of formula I according to any one of claims 1 to 6. The liquid crystal medium of claim 7, which additionally comprises one or more compounds selected from the group consisting of compounds of formula II: Wherein: L ¹¹ represents R ¹¹ or X ¹¹ , L ¹² represents R ¹² or X ¹² , and R ¹¹ and R ¹² independently of each other represent a non-fluorinated alkyl group or a non-fluorinated alkoxy group having 1 to 17 carbon atoms. or with a non-fluorinated alkenyl group having 2 to 15 carbon atoms, an alkynyl group non-fluorinated, non-fluorinated alkylene group or a fluorinated alkoxy group, an alkyl group, X ¹¹ and X ¹² each independently represent F, Cl, Br, -CN, -NCS, -SCN, -SF ₅ , a fluorinated alkyl group having 1 to 7 carbon atoms or a fluorinated alkoxy group or a fluorinated alkenyl group having 2 to 7 carbon atoms, a fluorinated alkene An oxy or fluorinated alkoxyalkyl group, p, q independently represent 0 or 1, and Z ¹¹ to Z ¹³ independently of each other represent trans-CH=CH-, trans-CF=CF-, -C≡C - or a single button, and to Express independently of each other Wherein L independently represents a branched or unbranched alkyl, alkenyl or alkynyl group having 1 to 12 carbon atoms, wherein one or more "-CH ₂ -" groups may also independently pass through O Substituted, or represents C ₃ -C ₆ cycloalkyl, C ₃ -C ₆ cycloalkenyl, fluorinated alkyl or alkenyl, fluorinated alkoxy or alkenyloxy, F, Cl, Br, CN, NCS, SCN or SF ₅ . The liquid crystal medium of claim 7 or 8, wherein the concentration of the compound of formula I in the medium is in the range of from 5% to 95% by total. Use of a compound of formula I according to any one of claims 1 to 6 for use in a liquid crystal medium. Use of a compound of formula I according to any one of claims 1 to 6 for use in a component of high frequency technology. A method of preparing a liquid crystal medium according to any one of claims 7 to 9, characterized in that one or more compounds of the formula I are admixed with one or more other compounds and optionally with one or more additives. A component for high frequency technology, characterized in that it contains as an request item The liquid crystal medium of any one of 7 to 9. A component of claim 13 wherein it includes one or more functionally connected phase shifters. A use of a liquid crystal medium according to any one of claims 7 to 9 for a member of a high frequency technique. A "phase array" antenna characterized in that it comprises one or more components such as claim 13 or 14.