DIBENZOFURANS AND DIBENZOTHIOPHENES

Abstract

The present invention relates to dibenzofuans and dibenzothiophenes thiophenes of formula I

##STR00001##

in which the occurring groups and parameters have the meanings as indicated in claim 1, to liquid-crystalline media comprising same and to high-frequency components comprising these media, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, in particular for microwave phased-array antennas.

Claims

1. A compound of formula I ##STR00101## in which W denotes O or S, R.sup.1 and R.sup.2 denote H, an alkyl radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by —C≡C—, —CF.sub.2O—, —OCF.sub.2—, —CH═CH—, ##STR00102##  —O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen, where at least one of R.sup.1 and R.sup.2 is different from H, L on each occurrence, identically or differently, denotes alkyl, alkoxy, alkenyl, alkenyloxy or alkoxyalkyl, each having up 10 C atoms and in which one or more H atoms may be replaced by fluorine; or cycloalkyl or cycloalkenyl each having 3 to 6 C atoms; or halogen, CN, OH, SF.sub.5, r and s identically or differently, are 0, 1, 2 or 3, preferably 0 or 1, particularly preferably 0.

2. The compound according to claim 1, where the compound is selected from the group of compounds of the sub-formulae Ia-1 to Ia-4 ##STR00103## in which the occurring groups have the meanings given for formula I.

3. The compound according to claim 1, where the compound is selected from the group of compounds of the sub-formulae Ib-1 to Ib-4 ##STR00104## in which the occurring groups have the meanings given for formula I.

4. The compound according to claim 1, where R.sup.1 and R.sup.2 denote alkyl or alkenyl having up to 7 C atoms, and L on each occurrence, identically or differently, denotes F, Cl, CF.sub.3, OCF.sub.3, methyl, ethyl, n-propyl, isopropyl, cyclopropyl, or cyclobutyl.

5. A liquid-crystal medium, characterised in that it comprises one or more compounds according to claim 1.

6. The medium according to claim 5, where the medium comprises one or more compounds of formula II ##STR00105## in which L.sup.11 denotes R.sup.11 or X.sup.11, L.sup.12 denotes R.sup.12 or X.sup.12, R.sup.11 and R.sup.12, independently of one another, denote unfluorinated alkyl or unfluorinated alkoxy having 1 to 17, preferably having 3 to 10, C atoms or unfluorinated alkenyl, unfluorinated alkynyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, preferably alkyl or unfluorinated alkenyl, X.sup.11 and X.sup.12, independently of one another, denote F, Cl, Br, —CN, —NCS, —SCN, SF.sub.5, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, fluorinated alkenyloxy or fluorinated alkoxyalkyl having 2 to 7 C atoms, preferably CF.sub.3, OCF.sub.3, Cl, F or NCS, p, q, independently of one another, denote 0 or 1, Z.sup.11 to Z.sup.13, independently of one another, denote trans-CH═CH—, trans-CF═CF—, —C≡C— or a single bond, ##STR00106## independently of one another, denote ##STR00107## and L.sup.13 on each occurrence, independently of one another, denotes branched or unbranched alkyl, alkenyl or alkynyl having 1 to 12 C atoms, in which, independently of one another, one or more “—CH.sub.2—” groups may also be replaced by O, or denotes C.sub.3-C.sub.6 cycloalkyl, C.sub.3-C.sub.6 cycloalkenyl, fluorinated alkyl or alkenyl, fluorinated alkoxy or alkenyloxy, F, Cl, Br, CN, NCS, SCN or SF.sub.5.

7. (canceled)

8. A process for the preparation of a compound of formula I according to claim 1, characterised in that a compound of formula I′ ##STR00108## in which L, r and s have the meanings defined for formula I and X.sup.1 and X.sup.2 denote Cl, Br, I, alkanesulfonate, arylsulfonate or perfluoroalkanesulfonate, is reacted in a Sonogashira reaction with terminal alkynes.

9. A component for high-frequency technology, characterised in that it comprises a liquid crystal medium according to claim 5.

10. The component according to claim 9, where the component is suitable for operation in the microwave range.

11. The component according to claim 9, where the component is a tunable phase shifter, tunable filter, tunable matching network, tunable varactor or a LC based antenna element operable in the microwave region.

12. A microwave antenna array, characterised in that it comprises one or more components according to claim 9.

Description

SYNTHESIS EXAMPLES

Example 1: 3,7-Bis(n-hex-1-ynyl)dibenzothiophene (1)

[0118] ##STR00095##

[0119] A solution of 3,7-dibromodibenzothiophene (1.7 g, 5.0 mmol) and diisopropyl amine (27 mL) in THF (25 mL) are heated to 70° C. and XPhos Pd G2 (3.9 mg, 0.005 mmol), XPhos (0.006 mmol) and Cul (0.95 mg, 0.005 mmol) are added followed by n-1-hexyne (0.94 g, 11.4 mmol) after 10 min. The reaction mixture is stirred overnight at 70° C., filtered and concentrated i. vac. The residue is filtered through at pad of silica (n-heptane) and purified by flash chromatography (heptane). The product is recrystalized from heptane to give bis(n-hex-1-ynyl)dibenzothiophene as colourless crystals.

[0120] .sup.1H NMR (400 MHz, Chloroform-d) δ=7.79 ppm (d, J=8.2 Hz, 2H), 7.66 (d, J=1.3 Hz, 2H), 7.26 (dd, J=8.2, 1.4 Hz, 2H), 2.26 (t, J=7.0 Hz, 4H), 1.48-1.38 (m, 4H), 1.38-1.26 (m, 4H), 0.78 (t, J=7.3 Hz, 6H). EI-MS: 344.2.

[0121] Phase sequence: K 52 I

Δε: 2.6
Δn: 0.3220

Clp: 76.3° C.

[0122] γ.sub.1: 265 mPa s
(all values extrapolated from 10% in ZLI-4792)

[0123] In analogy to the synthesis of Example 1 are obtained:

Example 2: bis(n-oct-1-ynyl)dibenzothiophene

[0124] ##STR00096##

[0125] .sup.1H NMR (400 MHz, Chloroform-d) δ=8.02 ppm (d, J=8.2 Hz, 2H), 7.88 (d, J=1.3 Hz, 2H), 7.49 (dd, J=8.2, 1.4 Hz, 2H), 2.47 (t, J=7.1 Hz, 4H), 1.72-1.60 (m, 4H), 1.51 (dq, J=9.8, 6.9 Hz, 4H), 1.37 (tt, J=7.5, 3.5 Hz, 8H), 0.99-0.91 (m, 6H). EI-MS: 400.1.

[0126] Phase sequence: K 30 I

Δε: 1.5
Δn: 0.2756

Clp: 52.3° C.

[0127] γ.sub.1:316 mPa s
(all values extrapolated from 10% in ZLI-4792).

[0128] In analogy to the above described syntheses are obtained:

Example 3: 3,7-Bis(n-hex-1-ynyl)dibenzofuran (3)

[0129] ##STR00097##

Example 4: 3,7-Bis(n-hex-1-ynyl)dibenzofuran (4)

[0130] ##STR00098##

[0131] Under the same reaction conditions the corresponding 3-bromo-7-iododibenzofuran or 3-bromo-7-iododibenzothiophen can be reacted stepwise by using first half an equivalent of one homologue of a terminal alkyne followed by a second half equivalent of another homologue of a terminal alkyne to yield the following compounds:

Example 5: 3-(n-Hex-1-ynyl)-7-oct-1-ynyldibenzothiophene (5)

[0132] ##STR00099##

Example 6: 3-(n-Hex-1-ynyl)-7-oct-1-ynyldibenzofuran (5)

[0133] ##STR00100##

USE EXAMPLES

[0134] A nematic liquid-crystal medium N-1 having the composition and properties as indicated in the following table is prepared.

TABLE-US-00006 Composition Compound No. Abbreviation Physical properties 1 BCH-3F.F  12.0% T(N, I) = 92° C. 2 BCH-5F.F  10.0% Δn (20° C., 589.3 nm) = 0.0969 3 ECCP-30CF3  5.0% Δε (20° C., 1 kHz) = 5.2 4 ECCP-50CF3  5.0% γ.sub.1 (20° C.) = 134 mPa .Math. s 5 CBC-33F  2.0% 6 CBC-53F  2.0% 7 CBC-55F  2.0% 8 PCH-6F  8.0% 9 PCH-7F  6.0% 10 CCP-20CF3  8.0% 11 CCP-30CF3  12.0% 12 CCP-40CF3  7.0% 13 CCP-50CF3  11.0% 14 PCH-5F  10.0% Σ 100.0%

MIXTURE EXAMPLES

[0135] The Mixture Example M-1 is prepared from liquid-crystal host material N-1 above and the compound 1 of Synthesis Example 1 and consists of 90% by weight of N-1 and 10% by weight of compound 1. Accordingly, the Mixture Examples M-2 are prepared from liquid-crystal host material N-1 (90%) and Example 2 (10%), and Mixture Examples M-3 to M-6 are prepared from liquid-crystal host material N-1 (90%) and Examples 3 to 6 (10%), respectively.

TABLE-US-00007 TABLE 1 Properties of Mixture Examples, and N-1 (comparison) at 19 GHz (20° C.) Example Mixture ε.sub.r, ∥ tan δ.sub.εr, ∥ ε.sub.r, ⊥ tan δ.sub.εr, ⊥ τ η 1 M-1 2.5950 0.0044 2.2953 0.0118 0.1155 9.8 2 M-2 2.5620 0.0043 2.2770 0.0115 0.1112 9.7 3 M-3 4 M-4 5 M-5 6 M-6 Comparative N-1 2.56 0.0049 2.29 0.0126 0.107 8.5 Example

[0136] As can be seen from the data in Table 1, the use of a compound of formula I according to the invention results in an improvement of the material quality (η) of the medium N-1 due to a decrease of the dielectric loss (tan δ.sub.εr,∥) and an improvement of the tunability (τ).