LIQUID CRYSTALLINE MEDIA CONTAINING FLUORINATED OLIGOPHENYLS

Abstract: The invention relates to liquid crystalline media being a mixture of at least 2 compounds, characterized in that at least one compound is a fluorinated oligophenyl according to formulae (I) or (II).

Description: Liquid crystalline media containing fluorinated oligo- phenyls The invention relates to liquid cryaεtlline media being a mixture of at least 2 compounds, characterized in that at least one compound is a fluorinated oligophenyl according to formulae I or II wherein one of the groups Rl and R2 i.s F, OCF 3 , OCHF 2 oder NCS and the other group and R are independently from e^-ch other alkyl with 1 to 14 C atoms, wherein 1 or 2 CH 2 groups can be replaced by -O-, -0-CO-, -CO-O- and/or" -CH=CH- with the proviso that two O atoms are not directly linked, p is 0, 1 or 2 with the proviso that in case p = O at least one of X, Y and Z is F, X, Y, S, T and Z each denote independently from each other H or F, is one of the groups A-E -o is -CO- or -CE -, E is a single bond or -α-^C^-, r is 0 or 1, n is 0 or 1 with the proviso that in case n = 0 and p = 1 or 2 at least one of the groups X, Y and Z is F, and m is 0 or 1 with the proviso that in case m = 0 at least one of S and T is F and/or r - l. Liquid crystalline media according to the invention containing one or more compounds of formula I wherein in case n - 1, p = 1 and R 2 = OCF 3 and in case R 2 = F, p = O and Z = F at least one of X and Y denotes F, and/or one or more compounds of formula II wherein in case and is CO, E denotes -CH 2 CH 2 -are preferred. Both in formulae I and II in case n, m, or r = 0 an unsubεtituted 1,4 phenylene group and in case n, i or r = 1 a 1,4 phenylene group which is laterally monofluorinated in position 2 or 3. The invention was based on the object of discovering new stable liquid crystal or mesogenic compounds which are suitable as components of liquid crystal phases and, in particular, have advantageous values for optical and dielectric anisotropy. 3,4-Difluorbiphenyls exhibiting a comparatively low vis¬ cosity are described in the Japanese laid-open documents JP 59-59636 and JP 61-207359. These biphenyls, however, have a rather small mesophase range. 3,4-Difluorinated oligophenyls with 3 rings containing an ester group as linking group are claimed in JP 61-207359 and trifluoro- methoxy-2-fluoro-4-(4 » -alkoxybiphenyl-4-yl)-benzenes are disclosed in DE 3732 284. These compounds, however, exhibit rather poor values for Δε/ε .. It has now been found that fluorinated oligophenyls of formulae I and/or II are highly suitable as components of liquid crystal media. In particular, they have especially advantageous values of the dielectric anisotropy Δε, relatively high or high values of the optical anisotropy Δn and they exhibit a high temperature and UV stability. It is also possible to obtain stable liquid crystal phases with a broad nematic mesophase range and a comparatively low viscosity with the aid of these compounds. Depending on the choice of the substituents, the compounds of the formulae I and/or II can be used as the base materials from which liquid crystal media are predomin¬ antly composed; however, it is also possible for compounds of the formulae I and/or II to be added to liquid crystal base materials of other classes of compounds, for example t in order to influence the dielectric and/or optical aniso¬ tropy and/or the viscosity and/or the mesophase range of such a dielectric. The compounds of the formulae I and II are colourless in the pure state and are liquid crystalline in a temperature range which is favourably placed for electrooptical use. They are very stable towards chemicals, heat and light. The invention thus relates to liquid crystalline media with at least two liquid crystalline components, wherein at least one component is a compound of the formulae I or II and to liquid crystal display devices containing such medi . Furthermore, the invention relates to compounds of the formulae I and II. Above and below, R 1 , R , R 3 , X, Y, Z, S, T, p, Q, , E, n, m, and r have the meaning given unless expressly in¬ dicated otherwise. The compounds of formula I include laterally mono- or polyfluorinated bi-, ter- and quaterphenyls, the bi- and terphenyls being preferred. The following biphenyls are preferred: Especially preferred are those compounds of formula Ial with R 1 bei.ng F, OCF.. or OCHF 2 and R2 denoting alkyl, alkenyl, alkoxy or alkanoyloxy and, moreover, those com- 2 1 pounds with R being F, OCF- or OCHF 2 and R being n-alkyl, n-alkoxy or alkanoyloxy. In formula Ia2 the polar group particularly is F or OCF 3 . The compounds of the formula I further include laterally mono- or polyfluorinated compounds with 3 rings. The compounds of formulae Ibl - Ib4 are preferred: R 1 - Ib3 The monofluorinated compounds of formula Ib21 are pre¬ ferred: Especially preferred are those compounds of formula 1 2 Ib21 with denoting F, OCF 3 , OCHF 2 , or NCS and R being n-alkyl or n-alkoxy with 1-9 C atoms or, in particular, n-alkyl with 2-7 C atoms. The 3,4-di luorinated compounds of formula Ib41 F / R1" " (°/ " W "F n>41 are preferred; in this formula R preferably is alkyl, alkoxy or alkanoyloxy and, in particular, n-alkyl or n-alkoxy with 1-9 C atoms. Moreover, the following laterally monofluorinated compunds of formula Ibll are preferred: Especially preferred are those compound of formula Ibll with R being F, OCF 3 or OCHF 2 and, in particular, F or 0CF. 3 and with R denoting alkyl, alkoxy or alkanoyloxy wi .th 1-9 C atoms and, moreover, those compounds with R2 being F, OCF 3 or OCHF 2 and R being n-alkyl, n-alkoxy or alkanoyloxy. Moreover the following laterally bifluorinated compounds of formula Ib41 are preferred: Especially preferred are those copounds of formula Ib22 with R - F or 0 F 3 and with R = F, OCHF 2 or OCF 3 and = n-alkyl or n-alkoxy with 1-9 C atoms. Further the following laterally bifluorinate compounds according to formula Ib31 are preferred: " The compounds of the formula I further include' " laterally mono-or polyfluorinated compounds with 4 rings, ϊiie compounds of the part formulae Icl-Ic3 are preferred. In the part formulae Icl-Ic3 n and n' denote independantly from each other 0 or 1. The compounds of the formulae Icl-Ic3 which are laterally mono- or difluorinated are preferred. In laterally higher fluorinated compounds the terminal group which is not F, OCF 3 , OCK-. 2 or NCS preferably means alkyl or alkoxy. Formula II comprises mono- or polyfluorinated compounds with 3 or 4 rings exhibiting an ester resp. an ether group or an ester resp. an ether group and an ethylene group as linking groups. Compounds with 3 rings are preferred. In 4 ring compounds with E denoting -CH 2 CH 2 - R is preferably alkyl or alkoxy with 1-7 C atoms. The following compounds with 3 rings are especially preferred. R 3 -(Ϊ 0)> Ha2 F - θ - Ha5 '-Q-coo- - CH CH 2 -ι -F Ha7 IlalO R' IIal2 t 3 - -CH 2 0-< -< -F Hal3 In the part formulae Hal - IIal4 m and m 1 independently from each other denote 0 or 1. These compounds are preferably laterally mono- or di- substituted. Higher fluorinated compounds are useful as components of media for twisted nematic displays becaμse they generally very effectively supress smectic structures. The following compounds according to formula II with 4 rings are preferred: ιrb5 In the part formulae IIbl-IIb8 m' and * ' independently from each other denote 0 or 1. For higher fluorinated 3 compounds R means preferably alkyl or alkoxy. Monofluorinated compounds, however, are expecially preferred because they generally exhibit a comparatively low viscosity. R 3 and that terminal group of the compounds of formula I which is not F are independently from each other alkyl, alkoxy, oxaalkyl, alkanoyloxy or alkenyl and both can exhibit a straight-chain or branched structure. Alkyl or alkoxy preferably are straight-chain and have 2, 3, 4, 5, 6 or 7 C atoms. Accordingly they are prefer¬ ably ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy, also methyl, , octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetra- decyl, pentadecyl, methoxy, octoxy, nonoxy, decoxy, un- decoxy, dodecoxy-,- tridecoxy or tetradecoxy. Oxaalkyl is preferably straight-chain 2-oxapropyl (= methoxy- methyl), 2-(= ethoxymethyl) or 3-oxybutyl (= 2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4- 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl or 2-, 3-, 4-, 5-, 6-, 7-, 8-, or 9-oxadecyl. Alkenyl is preferably straight-chain and has 2 or 10 C atoms. It is accordingly, in particular, vinyl, prop-1- or prop-2- enyl, but-1-, -2- or -3-enyl, pent-1-, -2-, -3- or -4-enyl, hex-1-, -2-, -3-, -4- or -5-enyl, hept-1-, -2-, -3-/ -4-, -5- or -6-enyl, oct-1-, -2-, -3-, -4-, -5 6- or -7-enyl, non-1-, -2-, -3-, -4-, -5-, -6-, -7- or -8-enyl or dec-1-, -2-, -3-, -4-, -5-, -6-, -7-, -8- or -9-enyl. Compounds of the formulae I and II containing a branched terminal group can occasionally be of importance because of an improved solubility in the customary liquid crystal base materials, but in particular as chiral doping substances if they are optically active. Smectic compounds of this type are suitable as components of ferro-electric niaterials. Branched groups of this type as a rule contain not more than one chain branching. Preferred branched radicals are isopropyl, 2-butyl (= 1-methylpropyl) • , isobutyl (- 2- methylpropyl, 2-methylbutyl, isopentyl, (« 3-methylbutyl), 2-methylpentyl, 2-ethylhexyl, 2-propylpentyl, 2-octyl, isopropoxy, 2-methylpropoxy, 2-methylbutoxy, 3-methylbut- oxy, 2-methylpentoxy, 3-methylpentoxy, 2-ethylhexoxy, 2-methylhexoxy, 1-methylhexoxy, 1-methylheptoxy (= 2-octyl- oxy), 2-oxa-3-methylbutyl, 3-oxa-4-methylpentyl, 4-methyl- hexyl, 2-nonyl, 2-decyl, 2-dodecyl, 6-methyloctoxy 6- methyloctanoyloxy, 4-methylheptyloxycarbonyl, 2-methylbuty- ryloxy, 3-methylvaleryloxy, 4-methylhexanoyloxy, 2-chloro- 4-methylvaleryloxy, 2-chlor-3-methylvaleryloxy, 2-methyl-3- oxapentyl- and 2-methyl-3-oxahexyl. In the case of compounds with a branched terminal group, formulae I and II include both the optical antipodes and racemates as well as mixtures thereof. Of the compounds of the formulae I and II and sub- formulae thereof, those in which at least one of the radicals contained therein has one of the preferred mean¬ ings given are preferred. The compounds of the formulae I and II are prepared by methods which are known per se, such as are described in the literature (for example in the standard works, such as Houben- eyl, Methoden der Organischen Chemie [Methods of Organic Chemistry] , Georg Thieme Verlag, Stuttgart), and in particular under reaction conditions which are known and suitable for the reactions mentioned. Variants which are known per se and are not mentioned in more detail here can also be used in this connection. If desired, the starting materials can also be formed in situ, such that they are not isolated from the reac¬ tion mixture but are immediately reacted further to give the compounds of the formulae I and II. The compounds of formula I can be prepared, for example, by coupling mono- or polyphenyl boronic acids III with 4-bromomono- or polyphenyls with t + u = p + 2 and R 1 and R2 having the meanin" ' g given above. Both reactants of formulae III and IV are laterally fluorinated appropriately to give compounds of formula I; this is indicated schematically by the formula . The compounds of formula I with R, or R j being 0^E 3 , NCS or F can further be prepared, for example, by coupling Zn mono- or polyphenyls with 4-bromomono- or polyphenyls of formula IV via transitio metal catalysis t ,, uu, R 1, R2 and having the meaning indicated. This reaction is described in great detail in E. Poetsch, Kontakte, 1988(2), I5r, Darmstadt. * Compounds of the formula II can be obtained for example via the esterification of carboxylic acids (W = -CO-) resp. via the etherification of alcohols (W = -CH 2 ») of the formulae Via and VIb R 3 -Q-COOH Via R 3 -Q-OH VIb with phenols of formula VII the meaning of Q, S, T, E and m being indicated above. Other methods of making compounds of formulae I and II are apparent to those skilled in the art. In addition to one or more compounds of formula I the liquid crystal media according to the invention prefer¬ ably contain 2-40 components and in particular 4-30 com¬ ponents. Liquid crystal media being composed of one or more compounds of formula I and 7-25 other components are especially preferred. These additional components are preferably chosen from the nematic or nematogenic (monotropic or isotropic) substances; in particular from the classes of azoxy- benzenes, benzylideneanilines, biphenyls, terphenyls, phenyl or cyclohexyl benzoates, phenyl or cyclohexyl cyclohexanecarboxylates, phenyl or cyclohexyl cyclohexyl- t - 19 - benzoates, phenyl or cyclohexyl cyclohexylcyclohexane- carboxylates, cyclohexylphenylbenzoates, cycloheaςl- phenyl cyclohexanecarboxylates, cyclohexylphenyl cyclo- hexylcyclohexanecarboxylates, phenylcyclohexanes, cyclohexylbiphenyls, phenylcyclohexylcyclohexanes, cyclohexylcyclohexanes, cyclohexylcyclohexenes, cyclo- hexylcyclohexylcyclohexene, 1,4-bis-cyclohexylbenzenes, 4,4 , -bis-cyclohexylbiphenyls / phenyl- or cyclohexyl- pyrimidines, phenyl- or eyelohexylpyridines , phenyl- or cyclohexyldioxanes, phenyl- or cyclohexyl-l,3-dithianes, 1,2-diphenylethanes, 1,2-dicyclohexylethaneε, 1-phenyl- 2-cyclohexylethanes, l-cyclohexyl-2-(4-phenyl-cyclohexyl)- ethanes, l-cyclohexyl-2-biphenylethanes, l-phenyl-2-cyclo¬ hexyl-phenylethanes, optionally halogenated stilbeneε, benzyl phenyl ethers, tolanes and substituted cinnamic acids. ' : " The 1,4-phenylene groups of these compounds may be fluorinated. The most important compounds which are possible consti- tuents of liquid crystal media according to the invention can be characterized by the formalae 1, 2, 3, 4 and 5: R I - -U-R" 1 R'-L-COO-ϋ-R" 2 R , - -OOC-U--R" 3 R'-L-C^CE^-U-R" 4 R f -I--C=C-U-R" 5 In the formulae 1, 2, 3, 4 and 5 L and U may be equal or different from each other. L and U independently from each other denote a bivalent residue selected from the group consisting of -Phe-, -Cyc-, -Phe-Phe-, -Phe-Cyc-, -Cyc-Cyc-, -Pyr-, -Dio-, -G-Phe-, -G-Cyc- and their mirror images; in this compilation of residues Phe denotes un- substituted or fluorinated 1,4-phenylen, Cyc trans- 1,4- cyclohexylene or 1,4-cyclohexenylen, Pyr pyrimidine-2,5- diyl or pyridine-2,5-diyl, Dio l,3-dioxane-2,5-diyl and G 2-(trans-l,4-cyclohexyl)-ethyl, pyrimidine-2 ,5-diyl , pyridine-2,5-diyl or l,3-dioxane-2,5-diyl. One of the residues and U is preferably Cyc, Phe or Pyr. U preferably denotes Cyc, Phe or Phe-Cyc. The liquid crystal media according to the invention preferably con- tain one or more components selected from the compounds of formulae 1, 2, 3, 4 and 5 with L and U meaning Cyc, Phe and Pyr, said liquid crystal media further containing at the same time one ore more components selected from the compounds of formulae 1, 2, 3, 4 and 5 with one of the residues L and ϋ denoting Cyc, Phe and Pyr and the other residue being selected from the group consisting of -Phe-Phe-, -Phe-Cyc-, -Cyc-Cyc-, -G-Cyc-, said liquid crystal media containing in addition to this optionally one or more components selected from the compounds of formulae 1, 2, 3, 4 and 5 with L and U being selected from the group consisting of -Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and -G÷-Cyc. In a preferred subgroup of the compounds of formulae 1, 2, 3, 4 and 5 (subgroup 1) R 1 and R" are independent- ly from each other alkyl, alkenyl, alkoxy, alkenoxy with up to 8 carbon atoms. R f and R" differ from one another in most of these compounds, one of the residues usually being alkyl or alkenyl. In another preferred subgroup of the compounds of formulae 1, 2, 3, J 4 and 5 (subgroup 2) R" denotes -CN, -CF 3 , -F, -Cl or -NCS while R' has the meaning indicated in subgroup 1 and is preferably alkyl or alkenyl. Other variants of the envisaged substituents in the compounds of formulae 1, 2, 3, 4 and 5 are also customary. Many such substances are commercially available. All these substances are obtainable by methods which are known from the literature or by analogous methods. The liquid crystal media according to the invention pre¬ ferably contain in addition to components selecteα- from subgroup 1 also components of subgroup 2, the percentage of these components being as follows: subgroup 1: 20 to 90 %, in particular 30 to 90 % subgroup 2: 10 to 50 %, in particular 10 to 50 % In these liquid crystal media the percentages of the com¬ pounds according to the invention and the compounds of sub¬ group 1 and 2 may add up to give 100 %. The media according to the invention preferably contain 1 to 40 %, in particular 5 to 30 % of the compounds according to the invention. Media containing more than 40 %, in particular 45 to 90 % of the compounds accor¬ ding to the invention are further preferred. The media contain preferably 3, 4 or 5 compounds according to the invention. Liquid crystalline media according to the invention containing one or more components selected from the group comprising compounds of the furmlae Ial, Ia2, Ibl, Ib2, Ib3, Ib4, Ib5, Ib21, Ib41, Ibll, Ib22, Ib31, Icl, Ic2, Ic3, Hal, IIa2, Ha3, Ha4, Ha5, Ha6, IIa7, Ha8, Ha9, HalO, Hall, Hal2, Hal3, Hal4, Hal5, Hal6, IIal7, Hal8, Hal9, Ha20, Hbl, IIb2, Hb3, Hb4, Hb5, Hb6, IIb7 and Hb8 are preferred. Liquid crystalline media containing one or more compounds selected from the group comprising laterally fluorinated bi-, ter- and quaterphenyls of the formulae Ial, Ia2, Ibl, Ib3, Ib4, Ib5, Ib21, Ib41, Ibll, Ib31, Ib22, Icl, Ic2 and Ic3 are preferred. Especially preferred are liquid crystalline media one or more components of which are selected from a smaller subgroup consisting of compounds of formulae Ial, Ia2, Ibl, Ib2, Ib3, Ib4, Ib21, Ib41, Ibll, Ib22, Ib31 and Ic3. Further preferred are those liquid crystalline media con- taining one or more mono- or polyfluorinated esters and/or ethers chosen from the following group: Hal, IIa2, IIa3, IIa4, IIa5, Ilaδ, Ha7, Ha8, Ha9, HalO, Hall, Hal2, Hal3, Hal4, Hal5, Hal6, Hal7, Hal8, Hal9, Ha20, Hbl, Hb2, Hb3, Hb4, Hb5, Hb6, Hb7 and IIb8. Especi- ally preferred are liquid crystal media containing at least one ester and/or ether taken from the following smaller subgroup of compounds: Hal, IIa2, IIa3, IIa4, IIa5, Ilaβ, IIa7, Ha9, Hall, IIal2, Hal3, Hal4, Hal5, Hal6, Hbl, Hb2, IIb3, Hb4 and Hb5. Liquid crystalline media according .to the invention are characterized by advantageous values of the dielectric anisotropy Δε and the viscosity η, by a high clearing point T and a wide nematic range and, in particular, by advantageous values of the optical anisotropy Δn and a high UV and temperature stability. The liquid crystalline t media according to the invention can preferably be used, for example, in twisted nematic (TN) cells, especially in STN (supertwisted nematic) cells with a twist angle > 90 °, further in electrooptical systemsconsisting of nematic microdroplets embedded in a transparent matrix like for example PDLC (polymer dispersed liquid crystal) or NCAP (nematic curvilinear aligned phase) devices or in electrooptical PN (polymer network) systems which are described, for example, in EP 0,313,053. Further, the media can preferably be used for active-matrix^adressed TN cells like TFT-TN (thin-film-transistar TN) or MIM-TN (metal-insulator-metal TN) cells, especially, for example, for projection systems or other displays being operated under the so-called 2. minimum-condition or with comparable or even higher values of d . Δn. The media according to the invention are prepared in a manner which is customary per se. As a rule, the com¬ ponents are dissolved in one another, advantageously at elevated temperature. The liquid crystal media accor¬ ding to the invention can be modified by suitable addi¬ tives so that they can be used in all the types of liquid crystal display devices. Such additives are known to the expert and are described in detail in the literature (H. Kelker/R. Hatz, Handbook of Liquid Crystals, Verlag Chemie, Weinheim, 1980). For example, it is possible to add pleochroic dyestuffs to prepare colored guest-Jtiost systems or substances for modifying the dielectric aniso¬ tropy, the viscosity and/or the orientation of the nematic phases. The following examples are to be construed as merely illustrative and not limitative, m.p. = melting point, c.p. - clearing point. In the foregoing and in the fol¬ lowing all parts and percentages are by weight and the temperatures are set forth in degrees Celsius. "Custo- mary work-up" means that water is added, the mixture is extracted with methylene chloride, the organic phase is seperated off, dried and evaporated, and the product is purified by crystallization and/or chromatography. Further are: C: crystalline-solid state, S: smectic phase (the index denoting the typ of smectic phase), N: nematic phase, Ch: cholesteric phase, I: isotropic phase. The number being embraced by 2 of these symbols denotes the tem- perature of phase change. Examples for production Example 1 Step 1: 0.22 mol 4'-pentyl-4-bromobiphenyl is dissolved in 200 ml tetrahydrofuran and metallized by reaction with 0.22 mol magnesium turnings in a nitrogen atmosphere. 0.22 mol trimethyl borate is added dropwise. Addition of 150 ml of 20 % hydrochloric acid solution and customary work-up give 4-pentylbiphenyl-4'-boronic acid. Step 2: 0.44 mol 4-pentylbiphenyl-4*-boronic acid, 0.036 mol l-bromo-2,4-difluorobenzene, 70 ml toluene, 20 ml industrial methylated spirits and 35 ml 2m sodium carbonate are mixed under nitrogen and stirred and heated under reflux with 0.5 g tetra-(triphenylphosphine)- palladium for 16 hours. Customary work-up gives 2,4-di- fluoro-4•'-pentylterphenyl exhibiting the follwoing data: C 82.2 S A 122.9 N 133.2 I. - 25 - The following compounds are prepared analogously: 3,4-difluoro-4 « •(hex-3-enyl)-terphenyl 3,4-difluoro-4' (hex-5-enyl)-terphenyl 3,4-difluoro-4 • (hept-3-enyl)-terphenyl 3,4-difluoro-4 » (hept-6-enyl)-terphenyl 3,4-difluoro-4' (3-oxaheptyl)-terphenyl 3,4-difluoro-4' (5-oxaheptyl)-terphenyl 3,4-difluoro-4' ■(6-oxaheptyl)-terphenyl 3,4-difluoro-4' •(7-oxaheptyl)-terphenyl Example 2 4-fluoro-2*-fluoro-4* '-propylterphenyl is prepared ana¬ logously to example 1 from 4-fluorophenyl boronic acid and 4-bromo-2-fluoro-4'-propylbiphenyl. This compound exhibits the following physical data: C 98.3 N 122.8 I The following compounds are prepared analogously: N 113.6 I 4-fluoro-2"-fluoro-4 ,l -propylterphenyl is prepared analo¬ gously to example 1 from 4-fluorophenyl boronic acid and 4-bromo-2*-fluoro- '-propylbiphenyl. The following com¬ pounds are prepared analogously: 4-fluoro-2"-fluoro-4"- -methylterphenyl 4-fluoro-2"-fluoro-4"<-ethylterphenyl 4-fluoro-2"-•fluoro-4"--butylterphenyl 4-fluoro-2"-fluoro-4"--pentylterphenyl 4-fluoro-2'*-■fluoro-4"'-hexylterphenyl 4-fluoro-2"«■fluoro-4"-heptylterphenyl 4-fluoro-2"-■fluoro-4"'-octylterphenyl 4-fluoro-2"-■fluoro-4"-nonyl erphenyl 4-fluoro-2"-■fluoro-4"-decylterphenyl 4-fluoro-2"«•fluoro-4"-methoxyterphenyl 4-fluoro-2"-■fluoro-4"-propoxyterphenyl 4-fluoro-2"-■fluoro-4"-butoxyterphenyl 4-fluoro-2"-■fluoro-4"-pentoxyterphenyl 4-fluoro-2"-■fluoro-4"-hexoxyterphenyl 4-fluoro-2"--fluoro-4"-oxtoxyterphenyl Example 4 3,4-difluoro-2'-fluoro-4' '-propylterphenyl is prepared analogously to example 1 from 3,4-difluorophenyl boronic acid and 4-bromo-2-fluoro-4'-propylphenyl The following compounds are prepared analogously: 3,4-difluoro-2 '-fluoro-4 1 -ethylterphenyl 3,4-difluoro-2'-fluoro-4 '-butyl erphenyl 3,4-difluoro-2 1 -fluoro-4 '-pentylterphenyl 3,4-difluoro-2 1 -fluoro-4 '-hexylterphenyl 3,4-difluoro-2'-fluoro-4 '-heptylterphenyl 3,4-difluoro-2'-fluoro-4 '-octylterphenyl 3,4-difluoro-2•-fluoro-4 '-nonylterphenyl 3,4-di luoro-2'-fluoro-4 '-decylterphenyl 3,4-difluoro-2'-fluoro-4 '-butoxyterphenyl 3,4-difluoro-2'-fluoro-4 '-pentoxyterphenyl 3,4-difluoro-2•-fluoro-4 '-hexoxyterphenyl 3,4-difluoro-2'-fluoro-4 •-heptoxyterphenyl 3,4-difluoro-2'-fluoro-4 '-octoxyterphenyl 3,4-difluoro-2'-fluoro-4 '-nonoxyterphenyl 3,4-difluoro-2*-fluoro-4 '-decoxyterphenyl 3,4-difluoro-2'-fluoro-4 '-(but-3-enyl)>-terphenyl 3,4-difluoro-2 « -fluoro-4 '-(pent-4-enyl)-terphenyl 3,4-difluoro-2'-fluoro-4 •-(hex-5-enyl)-terphenyl Example 5 2,4-difluoro-4'-propylbiphenyl is prepared analogously to example 1 from 2,4-difluorophenyl boronic acid and 4-bromo-l-propylbenzene. - 29 - The following compounds are prepared analogously: 2,4-difluoro-4 '-pentylbiphenyl 2, -difluoro-4 '-hexylbiphenyl 2,4-difluoro-4 '-heptylbiphenyl 2,4-difluoro-4 '-octylbiphenyl 2,4-difluoro-4 1 -nonylbiphenyl 2, -difluoro-4 1 -decylbiphenyl 2, -difluoro-4 '-ethoxybiphenyl 2,4-difluoro-4 '-propoxybiphenyl C 57.6 I 2,4-difluoro-4 '-butoxybiphenyl 2,4-difluoro-4 '-pentoxybiphenyl 2,4-difluoro-4 *-hexoxybiphenyl 2,4-difluoro-4 1 -heptoxybiphenyl 2 ,4-difluoro-4 1 -octoxybiphenyl 2,4-difluoro-4 '-nonoxybiphenyl 2,4-difluoro-4 1 -decoxybiphenyl 2,4-difluoro-4 '-(hex-3-enyl)-biphenyl 2,4-difluoro-4 '-(hex-5-enyl)-biphenyl 2,4-difluoro-4 '-(hept-3-enyl)-biphenyl 2,4-difluoro-4 '-(hept-6-enyl)-biphenyl 2,4-difluoro-4 '-isobutyl-biphenyl 2,4-difluoro-4 1 -(3-methylbutoxy)-biphenyl Example 6 1.0 mol eq of 1-(3, ' 4-difluorophenyl)-2-(4-hydroxyphenyl)- ethane and 0.9 mol eq of trans-4-propylcyclohexyl carboxylic acid are treated in dichlormethane with ϊ.l mol eq of trifluor acetic anhydride. After 1 hour at * room temperature the reaction mixture is poured into water and t-tie separated organic layer is worked up customarily to give 4-[(3,4- difluorophenyl)-ethyl]-phenyl-4-proρylcyclohexyl carboxy- , late. The following compounds are prepared analogously: 4-[(3,4-difluorophenyl)-ethyl]-phenyl-trans-4-butyl- cyclohexylcarboxylate 4-[(3,4-difluorophenyl)-ethyl]-phenyl-trans-4-pentyl- cyclohexylcarboxylate 4-[(3,4-difluorophenyl)-ethyl]-phenyl-trans-4-hexyl- cyclohexylcarboxylate 4-[(3,4-difluorophenyl)-ethyl]-phenyl-trans-4-octyl- cyclohexylcarboxylate 4-[(3,4-difluorophenyl)-ethyl]-phenyl-trans-4-ethoxy- cyclohexylcarboxylate 4-[(3,4-difluorophenyl)-ethyl]-phenyl-trans-4-propoxy- cyclohexylcarboxylate 4-[(3,4-difluorophenyl)-ethyl]-phenyl-trans-4-butoxy- cyclohexylcarboxylate 4-[(3,4-difluorophenyl)-ethyl]-phenyl-trans-4-pentoxy- cyclohexylcarboxylate 4-[(3,4-difluorophenyl)-ethyl]-phenyl-trans-4-hexoxy- cyclohexylcarboxylate 2-fluoro-4-[(4-fluorophenyl)-ethyl]-phenyl-trans-4- propylcyclohexyl carboxylate 2-fluoro-4-[(4-fluorophenyl)-ethyl]-phenyl-trans-4- ethylcyclohexyl carboxylate 2-fluoro-4-[(4-fluorophenyl)-ethyl]-phenyl-trans-4- butylcyclohexyl carboxylate 2-fluoro-4-[(4-fluorophenyl)-ethyl]-phenyl-trans-4- hexylcyclohexyl carboxylate 2-fluoro-4-[(4-fluorophenyl)-ethyl]-phenyl-trans-4- heptylcyclohexyl carboxylate 2-fluoro-4-[(4-fluorophenyl)-ethyl]-ρhenyl-trans-4- octylcyclohexyl carboxylate 2-fluoro-4-[(4-fluorophenyl)-ethyl]-phenyl-trans-4- pentoxycyclohexyl carboxylate 2-fluoro-4-[(4-fluorophenyl)-ethyl]-phenyl-trans-4- hexoxycyclohexyl carboxylate 2-fluoro-4-[(4-fluorophenyl)-ethyl]-phenyl-tranε-4- heptoxycyclohexyl carboxylate Example 7 According to example 6 4-octoxyphenyl-4-(2,4-difluorphenyl)< phenyl-carboxylate is prepared from 4-octoxy benzoic acid and 4-(2,4-difluorophenyl)-phenol. The following compounds are prepared analogously: 4-pentoxyphenyl-4-(2,4-difluorphenyl)-phenyl-carboxylate 4-hexoxyphenyl-4-(2,4-difluorphenyl)-phenyl-carboxylate 4-heptoxyphenyl-4-( ,4-difluorphenyl)-phenyl-carboxylate 4-propylphenyl-4-(2,4-difluorphenyl)-phenyl-carboxylate 4-butylphenyl-4-(2,4-difluorphenyl)-phenyl-carboxylate 4-pentylphenyl-4-(2,4-difluorphenyl)-phenyl-carboxylate 4-hexylphenyl-4-(2,4-difluorphenyl)-phenyl-carboxylate 4-heptylphenyl-4-(2 ,4-difluorphenyl)-phenyl-carboxylate 4-oxtylphenyl-4-(2,4-difluorphenyl)-phenyl-carboxylate 4-pentylphenyl-2-fluoro-4-(4- luorophenyl)-phenyl carboxy¬ late 4-ethylphenyl-2-fluoro-4-(4-fluorophenyl)-phenyl carboxy¬ late 4-propylρhenyl-2-fluoro-4-(4-fluorophenyl)-phenyl carboxy¬ late 4-butylphenyl-2-fluoro-4-(4-fluorophenyl)-phenyl carboxy- late 4-hexylphenyl-2-fluoro-4-(4-fluorophenyl)-phenyl carboxy¬ late 4-heptylphenyl-2-fluoro-4-(4-fluorophenyl)-phenyl carboxy¬ late 4-octylphenyl-2-fluoro-4-(4-fluorophenyl)-phenyl carboxy¬ late 4-propoxyphenyl-2-fluoro-4-(4-fluorophenyl)-phenyl carboxy¬ late 4-butoxyphenyl-2-fluoro-4-(4-fluorophenyl)-phenyl carboxy- late 4-pentoxyphenyl-2-fluoro-4-(4-fluorophenyl)-phenyl carboxy¬ late 4-hexoxyphenyl-2-fluoro-4-(4- luorophenyl)-phenyl carboxy¬ late 4-heptoxyphenyl-2-fluoro-4-(4-fluorophenyl)-phenyl carboxy¬ late 4-octoxyphenyl-2-fluoro-4-(4-fluorophenyl)-phenyl carboxy¬ late trans-4-ethoxycyclohexyl-4-(2,4-difluorophenyl)-phenyl- carboxylate trans-4-propoxycyclohexyl-4-(2,4-difluorophenyl)-phenyl- carboxylate trans-4-butoxycyclohexyl-4-(2,4-difluorophenyl)-phenyl- carboxylate trans-4-pentoxycyclohexyl-4-(2 ,4-difluorophenyl)-phenyl- carboxylate trans-4-ethylcyclohexyl-4-(2,4-difluorophenyl)-phenyl- carboxylate trans-4-propylcyclohexyl-4-(2,4-difluorophenyl)-phenyl- carboxylate C 68.5 N 147.6 I trans-4-butylcyclohexyl-4-(2,4-difluorophenyl)-phenyl- carboxylate trans-4-pentylcyclohexyl-4-(2,4-difluorophenyl)-phenyl- carboxylate trans-4-hexylcyclohexyl-4-(2 ,4-difluorophenyl)-phenyl- carboxylate * " " trans-4-octylcyclohexyl-4-(2,4-difluorophenyl)-phenyl- carboxylate trans-4-ethylcyclohexyl-2-fluoro-4-(4-fluorophenyl)- phenyl carboxylate C 56.6 N 158.6 I trans-4-propylcyclohexyl-2-fluoro-4-(4-fluorophenyl)- phenyl carboxylate trans-4-butylcyclohexyl-2-fluoro-4-(4-fluorophenyl)- phenyl carboxylate trans-4-pentylcyclohexyl-2-fluoro-4-(4-fluorophenyl)- phenyl carboxylate trans-4-heptylcyclohexyl-2-fluoro-4-(4-fluorophenyl)- phenyl carboxylate trans-4-ethoxycyclohexyl-2-fluoro-4-(4-fluorophenyl)- phenyl carboxylate trans-4-propoxycyclohexyl-2-fluoro-4-(4- luorophenyl)- phenyl carboxylate trans-4-butoxycyclohexyl-2-fluoro-4-(4-fluorophenyl)- phenyl carboxylate trans-4-pentoxycyclohexyl-2-fluoro-4-(4- luorophenyl)- phenyl carboxylate trans-4-heptoxycyclohexyl-2-fluoro-4-(4-fluorophenyl)- phenyl carboxylate Example 8 According to example 63-fluoro-4-(4-fluorophenyl)-phenyl- trans-4-propylcyclohexyl-carboxylate is prepared from trans-4-propylcyclohexyl carboxylic acid and 2-fluoro-4- hydroxy-4'-fluorobiphenyl. This compound exhibits the following physical data: C 58.5 N 140.4 I '*' - The following compounds are prepared analogously: 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4-ethylcyclo- hexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4-butylcyclo- hexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4-pentylcyclo- hexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4-hexylcyclo- hexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4-heptylcyclo- hexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4—octylcyclo- hexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4-nonylcyclo- hexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4-decylcyclo- hexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4-ethoxylcyclo- hexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4-propoxylcyclo- hexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4-butoxycyclo- hexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4~pentoxycyclo- hexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4-hexoxycyclo- hexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4-heptoxycyclo- hexyl-carboxylate 3-fluoro-4-( -fluorophenyl)-phenyl-trans-4--octoxycyclo- hexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4-nonoxycyclo- hexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4-decoxycyclo- hexyl-carboxylate - 35 - 3-fluoro-4-(4-fluorophenyl)-phenyl-trans-4-(hex-3-enyl)- cyclohexyl-carboxylate 3-fluoro-4-(4-fluorophenyl)-phenyl-tranε-4-(hex-5-enyl)- cyclohexyl-carboxylate Example 9 According to example 6 4'-fluoro-3-fluoro-4-acetoxybi- phenyl is prepared from acetic acid and 4'-fluoro-3- fluoro-4-hydroxybiphenyl. This compound exhibits the following physical data: C 84.5 I The following compounds are prepared analogously: 4'-fluoro-3-fluoro-4-propionyloxybiphenyl 4'-fluoro-3-fluoro-4-butyryloxybiphenyl; clearing point < 20 °C 4'-fluoro-3-fluoro-4-valeryloxybiphenyl 4'-fluoro-3-fluoro-4-(6-methyloctanoyloxy)-biphenyl 4'-fluoro-3-fluoro-4-(2-methylbutyryloxy)-biphenyl 2' ,4'-difluoro-4-acetbxybiphenyl 2' ,4'-difluoro-4-propionyloxybiphenyl 2 • ,4'-difluoro-4-valeryloxybiphenyl 2•, '-difluoro-4-hexanoyloxybiphenyl 2' ,4'-difluoro-4-(4-methylhexanoyloxy)-biphenyl Example 10 0.1 mol 4'-hydroxy-2,4-difluorobiphenyl, 0.1 mol potassium carbonate and 0.1 mol trans-4-pentyl-l-bromomethylcyclo- hexane are heated in dimethylformamid to 120 °C for 15 hours. Customary work-up gives trans-(4-pentylcyclohexyl)7 methoxy-4-(2,4-difluorophenyl)-phenyl. The following compounds are prepared analogously: trans- (4-ethyl cyclohexyl ) -me thoxy-4- (2 , 4-di fluorophenyl )- phenyl trans-(4-propylcyclohexyl)-methoxy-4-(2,4-difluorophenyl)- phenyl C 110.3 I trans-( -heptylcyclohexyl)-methoxy-4-(2,4-difluorophenyl)- phenyl trans-(4-nonylcyclohexyl)-methoxy-4-(2,4-difluorophenyl)- phenyl trans-(4-ethoxycyclohexyl)-methoxy-4-(2,4-difluorophenyl)- phenyl trans-(4-propoxycyclohexyl)-methoxy-4-(2,4-difluorophenyl)- phenyl trans-(4-pentoxycyclohexyl)-methoxy-4-(2, -difluorophenyl)- phenyl trans-(4-heptoxycyclohexyl)-methoxy-4-(2, -difluorophenyl)- phenyl tranε-(4-nonoxycyclohexyl)-methoxy-4-(2,4-difluorophenyl)- phenyl tranε-(4-(but-3-enyl)-cyclohexyl)-methoxy-4-(2,4-difluoro¬ phenyl)-phenyl tranε-(4-isobutylcyclohexyl)-methoxy-4-(2,4-difluorophenyl)■ phenyl trans-(4-ethoxymethylcyclohexyl)-methoxy-4-(2,4-difluoro- phenyl)-phenyl trans-(4-ethylcyclohexy)-methoxy-4-(3,4-difluorophenyl)- phenyl trans-(4-propylcyclohexy)-methoxy-4-(3,4-difluorophenyl)- phenyl; C 73.7 N 100.8 I trans-(4-butylcyclohexy)-methoxy-4-(3,4-difluorophenyl)- phenyl tranε-(4-pentylcyclohexy)-methoxy-4-(3,4-difluorophenyl)- phenyl trans-(4-hexylcyclohexy)-methoxy-4-(3,4-difluorophenyl)- phenyl trans-(4-heptylcyclohexy)-methoxy-4-(3,4-difluorophenyl)- phenyl trans-(4-octylcyclohexy)-methoxy-4-(3,4-difluorophenyl)- phenyl trans-(4-methoxycyclohexy)-methoxy-4-(3 ,4-difluorophenyl)- phenyl trans-(4-ethoxycyclohexy)-methoxy-4-(3,4-difluorophenyl)- phenyl trans-(4-propoxycyclohexy)-methoxy-4-(3 ,4-difluorophenyl)- phenyl trans-(4-butoxycyclohexy)-methoxy-4-(3,4-difluorophenyl)- phenyl trans-(4-pentoxycyclohexy)-methoxy-4-(3,4-difluorophenyl)- phenyl trans-(4-hexoxycyclohexy)-methoxy-4-(3,4-difluorophenyl)- phenyl trans-(4-heptoxycyclohexy)-methoxy-4-(3,4-difluorophenyl)- phenyl trans-(4-octoxycyclohexy)-methoxy-4-(3,4-difluorophenyl)- phenyl trans-(4-nonoxycyclohexy)-methoxy-4-(3,4-difluorophenyl)- phenyl trans-(4-decoxycyclohexy)-methoxy-4-(3,4-difluorophenyl)- phenyl trans-(4-ethylcyclohexyl)-methoxy-2-fluoro-4-(4-fluoro- phenyl)-phenyl trans-(4-propylcyclohexyl)-methoxy-2-fluoro-4-(4-fluoro¬ phenyl)-phenyl C 70 N 98.8 I trans- 4-butylcyclohexyl)-methoxy-2-fluoro-4-(4-fluoro- phenyl -phenyl trans- 4-pentylcyclohexyl)-methoxy-2-fluoro-4-(4-fluoro- phenyl -phenyl trans- 4-ethoxycyclohexyl)-methoxy-2-fluoro-4-(4-fluoro- phenyl -phenyl tranε- 4-propoxycyclohexyl)-methoxy-2-fluoro-4-(4-fluoro- phenyl -phenyl trans- 4-pentoxycyclohexyl)-methoxy-2-fluoro-4-(4-fluoro- phenyl -phenyl trans- 4-heptoxycyclohexyl)-methoxy-2-fluoro-4-(4-fluoro- phenyl -phenyl trans- 4-ethylcyclohexyl)-methoxy-3-fluoro-4-(4-fluoro- phenyl -phenyl tranε- 4-propylcyclohexyl)-methoxy-3-fluoro-4-(4-fluoro- phenyl -phenyl; C 69.3 N 97.7 I trans- 4-butylcyclohexyl)-methoxy-3- luoro-4-(4-fluoro- phenyl -phenyl trans- 4-pentylcyclohexyl)-methoxy-3-fluoro-4-(4-fluoro- phenyl -phenyl trans- 4-hexylcyclohexyl)-methoxy-3-fluoro-4-(4-fluoro- phenyl -phenyl tranε- 4-heptylcyclohexyl)-methoxy-3-fluoro-4-(4-fluoro- phenyl -phenyl tranε- 4-octylcyclohexyl)-methoxy-3- luoro-4-(4-fluoro- phenyl -phenyl trans- 4-methoxycyclohexyl)-methoxy-3-fluoro-4-(4-fluoro- phenyl -phenyl trans- 4-ethoxycyclohexyl)-methoxy-3-fluoro-4-(4-fluoro- phenyl -phenyl tranε- 4-propoxycyclohexyl)-methoxy-3-fluoro-4-(4-fluoro- phenyl -phenyl trans-(4-butoxycyclohexyl)-methoxy-3-fluoro-4-(4-«fluoro- phenyl)-phenyl trans-(4-pentoxycyclohexyl)-methoxy-3-fluoro-4-(4-fluoro¬ phenyl)-phenyl trans-(4-hexoxycyclohexyl)-methoxy-3-fluoro-4-(4-fluoro¬ phenyl)-phenyl trans-(4-heptoxycyclohexyl)-methoxy-3-fluoro-4-(4-fluoro¬ phenyl)-phenyl trans-(4-octoxycyclohexyl)-methoxy-3-fluoro-4-(4-fluoro- phenyl)-phenyl Example 11 Difluoromethoxy-3-fluoro-4-[4-propyl-biphenyl-4'-yl]- benzene is prepared analogously to example 1 from 4- difluoromethoxy-2-fluorophenyl boronic acid and 4-bromo- 4•-propylbiphenyl. The following compounds are prepared analogously: Difluoromethoxy-3-fluoro-4-[4-methyl-biphenyl-4'-yl]- benzene Difluoromethoxy-3-fluoro-4-[4-ethyl-biphenyl-4'-yl]- benzene Difluoromethoxy-3-fluoro-4-[4-butyl-biρhenyl-4'-yl]- benzene Difluoromethoxy-3-fluoro-4-[4-pentyl-biphenyl-4'-yl]- benzene Difluoromethoxy-3-fluoro-4-[4-hexyl-biphenyl-4«-yl]- benzene Difluoromethoxy-3-fluoro-4-[4-heptyl-biphenyl- '-yl]- benzene Difluoromethoxy-3-fluoro-4- 4-methoxy-biphenyl-4'-yl]- benzene Difluoromethoxy-3-fluoro-4- 4-ethoxy-biphenyl-4'-yl]- benzene Difluoromethoxy-3-fluoro-4- 4-propoxy-biphenyl-4'-yl]- benzene Difluoromethoxy-3-fluoro-4- 4-butoxy-biphenyl-4*-yl]- benzene Difluoromethoxy-3-fluoro-4- 4-pentoxy-biphenyl-4'-yl]- benzene Difluoromethoxy-3-fluoro-4- 4-hexoxy-biphenyl-4'-yl]- benzene Difluoromethoxy-3-fluoro-4- 4-heptoxy-biphenyl-4'-yl]- benzene Difluoromethoxy-2-fluoro-4- 4-ethyl-biphenyl- '-yl]- benzene Difluoromethoxy-2-fluoro-4- 4-propyl-biphenyl-4'-yl]- benzene Difluoromethoxy-2-fluoro-4- 4-butyl-biphenyl-4'-yl]- benzene Difluoromethoxy-2-fluoro-4- 4-pentyl-biphenyl-4'-yl]- benzene Difluoromethoxy-2-fluoro-4- 4-hexyl-biphenyl-4 < -yl]- benzene Difluoromethoxy-2-fluoro-4- 4-heptyl-biphenyl-4'-yl]- benzene Difluoromethoxy-2-fluoro-4- 4-ethoxy-biphenyl-4'-yl]- benzene Difluoromethoxy-2-fluoro-4- 4-propoxy-biphenyl-4'-yl]- benzene Difluoromethoxy-2-fluoro-4-[4-butoxy-biphenyl-4'-yl]- benzene Difluoromethoxy-2-fluoro-4-[4-pentoxy-biphenyl-4'-yl]- benzene Difluoromethoxy-2-fluoro-4-[4-hexoxy-biphenyl-4 -yl]- benzene Difluoromethoxy-2-fluoro-4-[4-(hex-3-enyl)-biphenyl- 4'-yl]-benzene Difluoromethoxy-2-fluoro-4-[4-(hex-5-enyl)-biphenyl- 4'-yl]-benzene Difluoromethoxy-2-fluoro-4-[4-(hept-3-enyl)-bipnenyl- 4•-yl]-benzene Difluoromethoxy-2-fluoro-4-[4-(hept-5-enyl)-biphenyl- 4«-yi]-benzene Difluoromethoxy-2-fluoro-4-[4-(hept-6-enyl)-biphenyl- 1 -yi]-benzene-. Example 12 Difluoromethoxy-4-[4-propyl-3'-fluoro-biphenyl)-4',-yl]- benzene is prepared analogously to example 1 from 4-di- fluoromethoxyphenyl boronic acid and 3-fluoro-4-bromo-4'- propylbiphenyl. This compound exhibits the following physical data: C 96 S A 153 I The following compounds are prepared analogously: Difluoromethoxy-4-[4-methyl-3'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4-[4-ethyl-3'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4-[4-butyl-3'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4- 4-pentyl-3'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4- 4-hexyl-3'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4- 4-heptyl-3'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4- 4-methoxy-3'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4- 4-ethoxy-3*-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4- 4-propoxy-3'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4- 4-butoxy-3'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4- 4-pentoxy-3*-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4- 4-heptoxy-3'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4- 4-(hex-3-enyl)-3'-fluoro-biphenyl- 4'-yl]-benzene Difluoromethoxy-4- 4-(hex-4-enyl)-3'-fluoro-biphenyl- i-yi]-benzene benzene Difluoromethoxy-4- 4-(hex-5-enyl)-3'-fluoro-biphenyl- 4'-yl]-benzene Difluoromethoxy-4- 4-(2-methylpropyl)-3"-fluoro-biphenyl- 1-yi]--benzene Difluoromethoxy-4- 4-(2-chloro-pentyl)-3'-fluoro-biphenyl- i-yi]-benzene Difluoromethoxy-4- 4-(3-chloro-pentyl)-3'-fluoro-biphenyl- 4'-yl]-benzene Difluoromethoxy-4-[4-methyl-2'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4-[4-ethyl-2 • -fluoro-biphenyl-4'-yl]- benzene, S A 147 N 161 I Difluoromethoxy-4-[4-propyl-2'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4-[4-butyl-2'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4-[4-pentyl-2'-fluoro-biphenyl-4'-ylJ- benzene Difluoromethoxy-4-[4-hexyl-2'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4-[4-heptyl-2 • -fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4-[4-methoxy-2'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4-[4-ethoxy-2'-fluoro-biphenyl-4•-yl]- benzene Difluoromethoxy-4-[4-propoxy-2'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4-[4-butoxy-2'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4-[4-pentoxy-2'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4-[4-hexoxy-2'-fluoro-biphenyl-4'-yl]- benzene Difluoromethoxy-4-[4-heptoxy-2'-fluoro-biphenyl-4'-yl]• benzene Example 13 Difluoromethoxy-4-[2-fluoro-4-ethylbiphenyl-4'-yl]- benzene is prepared analogously to example 1 from 4- difluoromethoxyphenyl boronic acid and 2-fluoro-4- ethyl-4'-bromobiphenyl. The following compounds are prepared analogously: Di f luoromethoxy-4- 2-fluoro-4-methylbiphenyl-4'-yl]- benzene Difluoromethoxy-4- 2-fluoro-4-propylbiphenyl-4'-yl]- benzene Difluoromethoxy-4- 2-fluoro-4-butylbiphenyl-4'-yl]- benzene Difluoromethoxy-4- 2-fluoro-4-pentylbiphenyl-4'-yl]- benzene Difluoromethoxy-4- 2-fluoro-4-hexylbiphenyl-4'-yl]- benzene Difluoromethoxy-4- 2-fluoro-4-heptylbiphenyl-4'-yl]- benzene Difluoromethoxy-4- 2-fluoro-4-octylbiphenyl-4'-yl]- benzene Difluoromethoxy-4- 2-fluoro-4-nonylbiphenyl-4*-yl]- benzene Difluoromethoxy-4- 2-fluoro-4-decylbiphenyl-4 f -yl]- benzene Difluoromethoxy-4- 2-fluoro-4-methoxybiphenyl-4'-yl]- benzene Difluoromethoxy-4- 2-fluoro-4-ethoxybiphenyl-4*-yl]- benzene Difluoromethoxy-4- 2-fluoro-4-propoxybiphenyl-4*-yl]- benzene Difluoromethoxy-4- 2-fluoro-4-butoxybiphenyl-4*-yl]- benzene Difluoromethoxy-4- 2-fluoro-4-pentoxybiphenyl-4'-yl]- benzene Difluoromethoxy-4- 2-fluoro-4-hexoxybiphenyl-4'-yl]- benzene Difluoromethoxy-4- 2-fluoro-4-heptoxybiphenyl-4'-yl]- benzene - 45 - Difluoromethoxy-4-[2-fluoro-4-octoxybiphenyl-4'-yl]- benzene Difluoromethoxy-4-[2-fluoro-4-(hex-3-enyl)biphenyl-4'-yl]- benzene Difluoromethoxy-4-[2-fluoro-4-(hex-4-enyl)biphenyl-4'-yl]- benzene Difluoromethoxy-4-[2-fluoro-4-(hex-5-enyl)biphenyl- '-yl]- benzene Example 14 v Difluoromethoxy-2-fluoro-4-[4-propyl-3'-fluoro-biphenyl- 4 « _yi]-benzene is prepared analogously to example 1 from 4-difluoromethoxy-3-fluorophenyl boronic acid and 4-pro^pyl- 3'-fluoro-4'-bromobiphenyl. The following compounds are prepared analogously: Difluoromethoxy-2-fluoro-4-[4-methyl-3'-fluoro-biphenyl- 4 i -yi]-benzene Difluoromethoxy-2-fluoro-4-[4-ethyl-3'-fluoro-biphenyl- 4i-yi]-benzene Difluoromethoxy-2-fluoro-4-[4-butyl-3'-fluoro-biphenyl- 4'-yl]-benzene Difluoromethoxy-2-fluoro-4-[4-pentyl-3'-fluoro-biphenyl- 4 « _yi]-benzene Difluoromethoxy-2-fluoro-4-[4-hexyl-3'-fluoro-biphenyl- 4'-yl]-benzene Difluoromethoxy-2-fluoro-4-[4-heptyl-3•-fluoro-biphenyl- 4•-yi]-benzene Difluoromethoxy-2-fluoro-4-[4-methoxy-3*-fluoro-biphenyl- 4'-yl]-benzene Difluoromethoxy-2-fluoro-4- 4-ethoxy-3'-fluoro-biphenyl- 4 » -yi]-benzene Difluoromethoxy-2-fluoro-4- 4-propoxy-3'-fluoro-biphenyl- 4'-yl]-benzene Difluoromethoxy-2-fluoro-4- 4-butoxy-3'-fluoro-biphenyl- 4'-yl]-benzene Difluoromethoxy-2-fluoro-4- 4-pentoxy-3'-fluoro-biphenyl- 4 » -yi]-benzene Difluoromethoxy-2-fluoro-4- 4-hexoxy-3'-fluoro-biphenyl- 4'-yl]-benzene Difluoromethoxy-2-fluoro-4- 4-heptoxy-3'-fluoro-biphenyl- 4'-yl]-benzene Difluoromethoxy-2-fluoro-4- 4-oxtoxy-3'-fluoro-biphenyl- 4 « -yl]-benzene Difluoromethoxy-2-fluoro-4- 4-monoxy-3'-fluoro-biphenyl- 4 » -yi]-benzene Difluoromethoxy-2-fluoro-4- 4-decoxy-3'-fluoro-biphenyl- 4'-yl]-benzene Difluorome hoxy-2-fluoro-4- 4-methyl-2'-fluoro-biphenyl- 4'-yl)-benzene Difluoromethoxy-2-fluoro-4- 4-ethyl-2*-fluoro-biphenyl- 4'-yl)-benzene Difluoromethoxy-2-fluoro-4- 4-propyl-2'-fluoro-biphenyl- 4'-yl)-benzene Difluoromethoxy-2-fluoro-4- 4-butyl-2'-fluoro-biphenyl- 4i-yi)-benzene Difluoromethoxy-2-fluoro-4- 4-pentyl-2'-fluoro-biphenyl- 4*-yl)-benzene Difluoromethoxy-2-fluoro-4- 4-hexyl-2'-fluoro-biphenyl- 4'-yl)-benzene Difluoromethoxy-2-fluoro-4- 4-heptyl-2'-fluoro-biphenyl- 4'-yl)-benzene Difluoromethoxy-2-fluoro-4- 4-methoxy-2 • -fluoro-biphenyl- 4'-yl)-benzene Difluoromethoxy-2-fluoro-4- 4-ethoxy-2*-fluoro-biphenyl- 4'-yl)-benzene Difluoromethoxy-2-fluoro-4- 4-propoxy-2'-fluoro-biphenyl- 4 i -yi)-benzene Difluoromethoxy-2-fluσro-4- 4-butoxy-2*-fluoro-biphenyl- 4'-yl)-benzene Difluoromethoxy-2-fluoro-4- 4-pentoxy-2'-fluoro-biphenyl- 4'-yl)-benzene Difluoromethoxy-2-fluoro-4- 4-hexoxy-2'-fluoro-biphenyl- 4'-yl)-benzene Difluoromethoxy-2-fluoro-4- 4-heptoxy-2'-fluoro-biphenyl- 4'-yl)-benzene Difluoromethoxy-2-fluoro-4- 4-octoxy-2'-fluoro-biphenyl- 4'-yi)-benzene Difluoromethoxy-2-fluoro-4- 4-nonoxy-2 » -fluoro-biphenyl- 4i_yi)-benzene Difluoromethoxy-2-fluoro-4- 4-decoxy-2'-fluoro-biphenyl- 4'-yl)-benzene Example 15 16.5 g of 4-pentyl-3'-fluoro-4'-bromobiphenyl in 50 ml of THF are added to a boiling mixture of 1.2 g of magnesium and 25 ml of THF. When the addition is complete, the mix- ture is heated for a further 1 hours, cooled a-αd added to a solution of 6.7 g of 2nBr 2 in 50 ml of THF at 0°-15°. After stirring for 1 hour, 12.3 g of l-bromo-4-(trifluoro- methoxy)benzene and 0.75 g of PdCl 2 (dppf) are added. The mixture is stirred at 5 ° for 15 minutes and then at room temperature for 24 hours. The mixture is poured onto 100 ml of saturated NH 4 C1 solution, and the organic phase is separated off and extracted with toluene. After work-up of the organic phase and purification by chromatography and/or crystallization, trifluoromethoxy-4-[4-penty-3'-fluoro- biphenyl-4'-yl]-benzene is obtained. The following compounds are prepared analogously: Trifluoromethoxy-4- -4-methyl-3'-fluoro-biphenyl-4'-yl]- benzene Trifluoromethoxy-4- -4-ethyl-3'-fluoro-biphenyl-4'-yl]- benzene Trifluoromethoxy-4- -4-propyl-3'-fluoro-biphenyl-4'-yl]- benzene Trifluoromethoxy-4- -4-butyl-3'-fluoro-biphenyl-4'-yl]- benzene Trifluoromethoxy-4- -4-hexyl-3'-fluoro-biphenyl-4'-yl]- benzene Trifluoromethoxy-4- -4-heptyl-3'-fluoro-biphenyl-4'-yl]- benzene Trifluoromethoxy-4- - * 4-octyl-3'-fluoro-biphenyl-4'-yl]- benzene Trifluoromethoxy-4- -4-nonyl-3'-fluoro-biphenyl-4'-yl]- benzene Trifluoromethoxy-4- -4-methoxy-3'-fluoro-biphenyl-4'-yl]- benzene Trifluoromethoxy-4- -4-propoxy-3'-fluoro-biphenyl-4'-yl]- benzene Trifluoromethoxy-4- -4-butoxy-3'-fluoro-biphenyl-4'-yl]- benzene Trifluoromethoxy-4- -4-pentoxy-3'-fluoro-biphenyl-4'-yl3- benzene Trifluoromethoxy-4- -4-hexoxy-3'-fluoro-biphenyl-4'-yl]- benzene Trifluoromethoxy-4-[-4-heptoxy-3 • -fluoro-biphenyl-4'-yl]- benzene Trifluoromethoxy-4-[-4-octoxy-3'-fluoro-biphenyl-4'-yl]- benzene Trifluoromethoxy-4-[-4-nonoxy-3*-fluoro-biphenyl-4'-yl]- benzene Trifluoromethoxy-4-[-4-(hex-3-enyl)-3'-fluoro-biphenyl- 4'-yl]-benzene + Trifluoromethoxy-4-[-4-(hex-4-enyl)-3'-fluoro-biphenyl- 4'-yl]-benzene Trif luorome thoxy-4- [ -4- (hex- 5 -enyl ) -3 ' -f luoro-biphea jfetr i 4 ' -yl] -benzene Trifluoromethoxy-4-[-4-(2-methylpropyl)-3'-fluoro-biphenyl- 4 1 -yi]-benzene ** Example 16 Trifluoromethoxy-2-fluoro-4-[4-methyl-2'-fluøro-biphenyl- 4'-yl]-benzene is obtained analogously to example 15 from 4-methyl-2'-fluoro-4•-bromobiphenyl and l-bromo-3-fl-uoro- 4-(trifluoromethoxy)-benzene. The following compounds are prepared analogously: Trifluoromethoxy-2-fluoro-4-[4-ethyl- '-fluoro-biphenyl- 4'-yl]-benzene Trifluoromethoxy-2-fluoro-4-[4-propyl-2'-fluoro-biphenyl- 4'-yl]-benzene Trifluoromethoxy-2-fluoro-4-[4-butyl-2 • - luoro-biphenyl- 4'-yl]-benzene Trifluoromethoxy-2-fluoro-4-[4-pentyl-2'-fluoro-biphenyl- 41- i]-benzene Trifluororaethσxy-2-fluoro-4-[4-hexyl-2 ' -fluoro-biphenyl- 4 ' -yl ] -benzene Trifluoromethoxy-2-fluoro-4-[4-heptyl-2*-fluoro-biphenyl- 4 i -yl]-benzene Trifluoromethoxy-2-fluoro-4-[4-methoxy-2'-fluoro-biphenyl- 4 » _yi]-benzene Trifluoromethoxy-2-fluoro-4-[4-ethoxy-2'-fluoro-biphenyl- 4 « -yi]-benzene Trifluoromethoxy-2-fluoro-4-[4-propoxy-2'-fluoro-biphenyl- 4 1 -yi]-benzene Trifluoromethoxy-2-fluoro-4-[4-butoxy-2'-fluoro-biphenyl- 4'-yl]-benzene Trifluoromethoxy-2-fluoro-4-[4-pentoxy-2'-fluoro-biphenyl- 4--yi]-benzene Trifluoromethoxy-2-fluoro-4-[4-heptoxy-2'-fluoro-biphenyl- 4'-yl]-benzene Example 17 Trifluoromethoxy-4-[2-fluoro-4-ethoxybiphenyl- '-yl]- benzene is prepared analogously to example 15 from 2-fluoro-4-ethoxy-4*-bromobiphenyl and l-bromo-4-(tri- fluoromethoxy)-benzene. The following compounds are prepared analogously: Trifluoromethoxy-4-[2-fluoro-4-methylbiphenyl-4'-yl]- benzene Trifluoromethoxy-4-[2-fluoro-4-ethylbiphenyl-4*-yl]- benzene Trifluoromethoxy-4-[2-fluoro-4-propylbiphenyl- '-yl]- benzene Trifluoromethoxy-4-[2-fluoro-4-butylbiphenyl-4'-yl]- benzene Trifluoromethoxy-4- 2-fluoro-4-pentylbiphenyl-4'-yl]- benzene Trifluoromethoxy-4- 2-fluoro-4-hexylbiphenyl-4'-yl]- benzene Trifluoromethoxy-4- 2-fluoro-4-heptylbiphenyl-4'-yl]- benzene Trifluoromethoxy-4- 2-fluoro-4-methoxybiphenyl-4'-yl]- benzene Trifluoromethoxy-4- 2-fluoro-4-propoxybiphenyl-4'-yl]- benzene Trifluoromethoxy-4- 2-fluoro-4-butoxybiphenyl-4'-yl]- benzene Trifluoromethoxy-4- 2-fluoro-4-pentoxybiphenyl-4'-yl]- benzene Trifluoromethσxy-4- 2-fluoro-4-hexoxybiphenyl-4'-yl]- benzene Trifluoromethoxy-4- 2-fluoro-4-heptoxybiphenyl-4'-yl]- benzene Trifluoromethoxy-4- 2-fluoro-4-octoxybiphenyl-4'-yl]- benzene Example 18 4-(Trifluoromethoxy)-2•-fluoro-4'-propylbiphenyl is obtained analogously to example 15 from 4-propyl-2-fluoro-bromobenzene and 1-bromo-4-(trifluoromethox )-benzene. The following compounds are prepared analogously: 4-(Trifluoromethoxy)-2'• ■fluoro-4-methylbiphenyl 4-(Trifluoromethoxy)-2* ■ ■fluoro-4-ethylbiphenyl 4-(Trifluoromethoxy)-2' • ■ luoro-4-butylbiphenyl 4-(Trifluoromethoxy)-2'< ■fluoro-4-pentylbiphenyl 4-(Trifluoromethoxy)-2' ■fluoro-4-hexylbiphenyl 4-(Trifluoromethoxy)-2 ■ f luoro-4-heptylbiphenyl 4-(Trifluoromethoxy)-2 ■fluoro-4-octylbiphenyl 4-(Trifluoromethoxy)-2 • f luoro-4-nonylbiphenyl 4-(Trifluoromethoxy)-2 ■fluoro-4-decylbiphenyl 4-(Trifluoromethoxy)-2 ■ fluoro-4-methoxybiphenyl 4-(Trifluoromethoxy)-2 ■ fluoro-4-ethoxybiphenyl 4-(Trifluoromethoxy)-2 ■ fluoro-4-propoxybiphenyl 4-(Trifluoromethoxy)-2 ■fluoro-4-butoxybiphenyl 4-(Trifluoromethoxy)-2 -fluoro-4-pentoxybiphenyl 4-(Trifluoromethoxy)-2 ■fluoro-4-hexoxybiphenyl 4-(Trifluoromethoxy)-2 ■fluoro-4-heptoxybiphenyl 4-(Trifluoromethoxy)-2 ■fluoro-4-octoxybiphenyl 4-(Trifluoromethoxy)-2 -fluoro-4-nonoxybiphenyl 4-(Trifluoromethoxy)-2 -fluoro-4-decoxybiphenyl Examples of compositions Example A A.l. A liquid crystalline medium iε prepared consisting of: 80.8 % C 5 H n- °/ "V " CN \ 10 % C 3 H 7 - - -0-F Thiε mixture has a clearing point of N 42.4 - 42.5 °C I and a viscosity of 31.9 cSt at 20 °C. A.2. A liquid crystalline medium is prepared consisting of compounds which are all known from the state of the art: This mixture exhibits a clearing point of N 38 I and has a viscosity of 35 cSt at 20 °C. A comparison of the mixtures of A.l. and A.2. clearly demonstrates the advantageous properties of the com¬ pounds according to formula I. Example B B.l A liquid crystalline medium is prepared consisting of: 29.7 % 4-methylphenyl-4-pentylphenyl carboxylate 34.9 % 4-propylphenyl-4-pentylphenyl carboxylate 17.6 % 4-pentylphenyl-4-pentylphenyl carboxylate 17.8 % trans-4-propylcyclohexyl-2-fluoro-4-(4- fluorophenyl)-phenyl carboxylate Thiε mixture haε a clearing point of N 38.3 ° C I. B.2 A liquid crystalline medium is prepared consisting of compounds which are all known from the state of the art: 29.7 % 4-methylphenyl-4-pentylphenyl carboxylate 52.7 % 4-propylphenyl-4-pentylphenyl carboxylate 17.6 % 4-pentylphenyl-4-pentylphenyl carboxylate This mixture has a clearing point of N 18 I. A comparison of the mixtures of B.l and B.2 clearly demonstrates the advantageous properties of the compounds according to formula I.

Claims: Patent claims 1. Liquid crystalline medium being a mixture of at least two compounds, characterized in that at least one com¬ pound is a fluorinated oligophenyl according to formula I or II X z wherein ι 2 one of the groups R and R is F, OCF 3 , OCHF 2 or NCS and the other group and R are independently from each other alkyl with 1 to 14 C atoms, wherein 1 or 2 CH 2 groups can be replaced by -0-, -0-CO-, -CO-O- and/or -CH=CH- with the proviso that two O atoms are not dire ly linked, X, Y, S, T and Z each denote independently from each o H or F, p is 0, 1 or 2 with the proviεo that in case p = 0 at leaεt one of X, Y and Z is F, Q is one of the groups A-E -o-o- W is -CO- or -CH 2 -, E is a single bond or -CH 2 CH 2 -, r is 0 or 1 , n is 0 or 1 with the proviso that in case n = 0 and p = 1 or 2 at least one of the groups X, Y and Z is F, and m is 0 or 1 with the proviso that in case m = 0 at least one of S and T is F and/or r = 1. 2. Fluorinated oligophenyls according to formula I the meaning of X, Y, 2, n, p, R 1 and R2 being indicated in claim 1. 3. Fluorinated oligophenyls according to formula II the meaning of R , Q, W, S, T, E and m being indicated in claim 1. Liquid crystal display device, characterized in that it contains a liquid crystalline medium according to claim 1. Electrooptical display device, characterized in that it contains a liquid crystalline medium according,to claim 1.

Inventors: COATES DAVID, DORSCH DIETER, GREENFIELD SIMON, KURMEIER HANS-ADOLF, SMITH GRAHAM, COATES, DAVID, DORSCH, DIETER, GREENFIELD, SIMON, KURMEIER, HANS-ADOLF, SMITH, GRAHAM
Applicants: MERCK PATENT GMBH, MERCK PATENT GESELLSCHAFT MIT BESCHRAENKTER HAFTUNG
Application year: 1990
Main classification: C07C43
IPC codes: C07C25, C07C43, C07C69, C07C331, C09K19, G02F1