AROMATIC ISOTHIOCYANATES

Abstract

The present invention relates to a compound of formula T

##STR00001##

as defined in claim 1, to a liquid crystal medium comprising a compound of formula T and to high-frequency components comprising these media, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, tunable filters, tunable metamaterial structures, and electronic beam steering antennas, e.g. phased array antennas.

Claims

1. A compound of formula T ##STR00224## in which X denotes SF.sub.5, SF.sub.5—C≡C— or SF.sub.5—O—; Z.sup.T1, Z.sup.T2 identically or differently, denote —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —C≡C—C≡C— or a single bond; ##STR00225##  denote 1,4-phenylene, 1,4-naphthylene, 2,6-naphthylene, tetralin-5,8-diyl, thiophene-2,5-diyl, thieno[3,2-b]thiophene-2,5-diyl or selenophene-2,5-diyl, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L; L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF.sub.5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy each having 1 to 12 C atoms; and t is 0, 1 or 2.

2. The compound according to claim 1, wherein t is 1.

3. The compound according to claim 1, wherein Z.sup.T1 and Z.sup.T2, identically or differently, denote —CF═CF—, —C≡C— or a single bond.

4. The compound according to claim 1, wherein the compound is selected from the group of compounds consisting of the formulae T-1 T-2 and T-3 ##STR00226## in which X, ##STR00227##  have the meanings given in claim 1.

5. The compound according to claim 1, wherein ##STR00228##  denote ##STR00229##  in which R.sup.L, on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, or denote ##STR00230##  in which one or more H atoms may be replaced by a group R.sup.L or F, wherein R.sup.L denotes H or alkyl having 1 to 6 C atoms, and ##STR00231##  denotes ##STR00232##

6. The compound according to claim 1, wherein the radical X in formula T denotes SF.sub.5.

7. A liquid crystal medium comprising one or more compounds of formula T according to claim 1.

8. A component for high-frequency technology, characterized in that it comprises the liquid crystal medium according to claim 7.

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

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

11. A method for the production of a compound of formula T according to claim 1, characterized in that a compound of formula N ##STR00233## in which the occurring groups and parameters have the meanings given in claim 1, is reacted with carbon disulfide or with a thionocarbonic acid derivative X′—C(═S)—Y, in which X′ and Y, identically or differently, denote a leaving group.

12. A variable dielectric comprising a compound of formula T according to claim 1.

Description

EXAMPLES

Synthesis Examples

Abbreviations

[0222] dist. distilled [0223] DMF dimethylforamide [0224] DABCO 1,4-Diazabicyclo[2.2.2]octane [0225] THF Tetrahydrofuran [0226] MTB ether Methyl-tert-butyl ether [0227] XPhos 2-Dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl [0228] XPhos Pd G2 Chloro(2-dicyclohexylphosphino-2′,4′,6′-triisopropyl-1,1′-biphenyl)[2-(2′-amino-1,1′-biphenyl)palladium (II) [0229] Pd(dppf) 1,1′ bis(diphenylphosphine)ferrocene)dichloropalladium (II)

Synthesis Example 1

Step 1.1: 2,6-Difluoro-4-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]aniline

[0230] ##STR00192##

[0231] 4′-bromo-3,5-difluoro-[1,1′-Biphenyl]-4-amine (4.86 g. 17.1 mmol) is dissolved in DMF (100 ml) under nitrogen, bis(pinacolato)diboron (5.1 g 20.2 mmol), Pd(dppf) (0.14 g, 0.17 mmol) and potassium acetate (4.1 g, 43.0 mmol) is added, and the mixture is heated at 150° C. for 5 h. Water is added, the precipitate filtered off and dried i.vac. The crude product is purified by flash column chromatography to yield 2,6-difluoro-4-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]aniline.

Step 1.2: 6-Difluoro-4-[4-[4-(pentafluorosulfanyl)phenyl]phenyl]anilin

[0232] ##STR00193##

[0233] To bromophenylpentafluorosulfur (5.9 g, 21 mmol), 2,6-difluoro-4-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]aniline (7 g, 5.2 mmol) and tetrakis(triphenylphosphine)palladium (Pd(PPh.sub.3).sub.4 (0.3 g, 0.6 mmol) in THF (500 ml) a saturated aqueous solution of potassium carbonate (11.5 g, 84 mmol) is added under nitrogen and the reaction is heated under reflux for 12 h. Water is added, the mixture is extracted with dichloromethane and the combined organic layers are dried (MgSO.sub.4), and the solvent is evaporated. The crude product is purified by flash column chromatography to yield 6-difluoro-4-[4-[4-(pentafluoro-sulfanyl)phenyl]phenyl]aniline.

Step 3: [4-[4-(3,5-Difluoro-4-isothiocyanato-phenyl)phenyl]phenyl]ylpentafluoro-sulfur

[0234] ##STR00194##

[0235] Thiophosgene (0.48 ml, 6.24 mmol) is added dropwise to a mixture of 6-difluoro-4-[4-[4-(pentafluoro-sulfanyl)phenyl]phenyl]anilin (2.3 g, 5.6 mmol) and DABCO (1.56 g, 14.16 mmol) in dichloromethane (25 ml) at 0° C., and the reaction mixture is stirred for 1 h at room temperature. Brine is added and the layers are separated. The aqueous layer is extracted with dichloromethane, and the combined organic layers are dried (sodium sulfate) and concentrated in vacuo. The residue is purified by flash chromatography (heptane) followed by crystallization from heptane to give [4-[4-(3,5-difluoro-4-isothiocyanato-phenyl)phenyl]phenyl]yl-pentafluorosulfur as colorless crystals. [0236] Phase sequence: K 131 N 141 I. [0237] Δn=0.3264 [0238] Δε=1.61

[0239] In analogy to Synthesis Example 1 the following compounds are obtained:

TABLE-US-00004 No. Compound  2 [00195]  3 [00196]  4 [00197]  5 [00198]  6 [00199]  7 [00200]  8 [00201]  9 [00202] 10 [00203] 11 [00204] 12 [00205] 13 [00206] 14 [00207] 15 [00208] 16 [00209] 17 [00210] 18 [00211] 19 [00212] 20 [00213] 21 [00214] 22 [00215] 23 [00216] 24 [00217] 25 [00218] 26 [00219] 27 [00220] 28 [00221] 29 [00222] 30 [00223]

[0240] Application Test

[0241] The nematic liquid crystal host mixture N1, example mixture M1 and comparative example mixture C1 having the compositions and properties as indicated in the following tables are prepared and characterized with respect to their general physical properties and their applicability in microwave components at 19 GHz and 20° C.

TABLE-US-00005 Mixture N1 CPG-3-F 12.0% T(N, I) [° C.]: 92.5 CPG-5-F 10.0% Δn [589 nm, 20° C.]: 0.0969 CCEP-3-OT 5.0% n.sub.e [589 nm, 20° C.]: 1.5764 CCEP-5-OT 5.0% n.sub.o [589 nm, 20° C.]: 1.4795 CGPC-3-3 2.0% Δε [1 kHz, 20° C.]: 5.3 CGPC-5-3 2.0% ε.sub.|| [1 kHz, 20° C.]: 8.4 CGPC-5-5 2.0% ε.sub.⊥ [1 kHz, 20° C.]: 3.1 CP-6-F 8.0% γ.sub.1 [mPa s, 20° C.]: 128 CP-7-F 6.0% K.sub.1 [pN, 20° C.]: 13.2 CCP-2-OT 8.0% K.sub.3 [pN, 20° C.]: 19.6 CCP-3-OT 12.0% K.sub.3/K.sub.1 [pN, 20° C.]: 1.48 CCP-4-OT 7.0% V.sub.0 [V, 20° C.]: 1.66 CCP-5-OT 11.0% τ [20° C., 19 GHz]: 0.100 CP-5-F 10.0% ε.sub.r, || [20° C., 19 GHz]: 2.49 Σ 100.0% ε.sub.r, ⊥ [20° C., 19 GHz]: 2.24 tan δ.sub.ε r, || [20° C., 19 GHz]: 0.0049 tan δ.sub.ε r, ⊥ [20° C., 19 GHz]: 0.0125 η [20° C., 19 GHz]: 8.0

[0242] Example Mixture M1 consists of 90% of the medium N1 and 10% of the compound PPU-SF5-S of Synthesis Example 1.

[0243] Comparative Example Mixture M1 consists of 90% of the medium N1 and 10% of the compound PPU-TO-S known from prior art, in which the SF.sub.5-group of Synthesis Example 1 is replaced with a CF.sub.3O-group.

[0244] The following results are obtained:

TABLE-US-00006 Mixture: ε.sub.r, || tan δ.sub.ε r, || ε.sub.r, ⊥ tan δ.sub.ε r, ⊥ τ η M1 2.598 0.0048 2.284 0.0122 0.121 9.9 C1 2.594 0.0046 2.309 0.0116 0.110 10.2

[0245] It can be seen that the compound of formula T according to the invention shows the same excellent performance as the compound from the state of the art.