Isothiocyanato compounds, including tolanes
Liquid-crystalline media comprising one or more compounds of formula T as defined in claim 1 , and 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.
1. A compound of formula T
in which
R T denotes halogen, CN, NCS, R F , R F —O— or R F —S—, wherein R F denotes fluorinated alkyl having 1 to 12 C atoms or fluorinated alkenyl having 2 to 12 C atoms,
on each occurrence, independently of one another, denote
where
alternatively denote
in which one or two H atoms, identically or differently, are optionally replaced by a radical L 1 ;
L 1 and L 2 identically or differently, denote F, Cl straight chain alkyl having 1 to 12 C atoms, branched or cyclic alkyl having 3 to 12 C atoms or alkenyl having 2 to 12 C atoms;
Z T1 , Z T2 identically or differently, denote —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C— or a single bond, wherein at least one of Z T1 and Z T2 denotes —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH— or —C≡C—, and
t is 0 or 1.
2. The compound according to claim 1 , wherein Z T1 and Z T2 denote a single bond or —C≡C— and wherein at least one of Z T1 and Z T2 denotes —C≡C—.
3. The compound according to claim 1 , wherein the compound is selected from the compounds of the formulae T-1 to T-4
in which
L 11 and L 12 identically or differently, denote H, F, Cl, methyl or ethyl,
L 13 , L 14 and L 15 identically or differently, denote H, F, Cl, methyl, ethyl, n-propyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclopentenyl,
R T denotes halogen, CN, NCS, R F , R F —O— or R F —S—, wherein R F denotes fluorinated alkyl having 1 to 12 C atoms or fluorinated alkenyl having 2 to 12 carbon atoms.
4. The compound according to claim 1 , wherein R T denotes CF 3 or CF 3 O.
5. A liquid crystal medium comprising one or more compounds of formula T according to claim 1 .
6. The liquid crystal medium according to claim 5 , wherein the medium further comprises one or more compounds selected from the group of compounds of the formulae I, II and III,
in which
R 1 denotes H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17 C atoms, or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms, in which one or more CH 2 -groups are optionally replaced by
n is 0, 1 or 2,
on each occurrence, independently of one another, denote
in which R L , on each occurrence identically or differently, denotes H or alkyl having 1 to 6 C atoms,
and wherein
alternatively denotes
R 2 denotes H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17 C atoms, or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms, in which one or more CH 2 -groups are optionally replaced by
Z 21 denotes trans-CH═CH—, trans-CF═CF— or and
independently of one another, denote
in which R L , on each occurrence identically or differently, denotes H or alkyl having 1 to 6 C atoms;
R 3 denotes H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17 C atoms, or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms, in which one or more CH 2 -groups are optionally replaced by
one of Z 3′ and Z 32 , denotes trans-CH═CH—, trans-CF═CF— or —C≡C— and the other one, independently thereof, denotes trans-CH═CH—, trans-CF═CF— or a single bond, and
independently of one another, denote
in which R L , on each occurrence identically or differently, denotes H or alkyl having 1 to 6 C atoms, and wherein
alternatively denotes
7. The liquid-crystal medium according to claim 6 , wherein the medium comprises one or more compounds selected from the group of compounds of the formulae I-1 to I-5:
in which
L 1 , L 2 and L 3 on each occurrence, identically or differently, denote H or F, and
R 1 ,
have the meanings given for formula I in claim 6 .
8. The liquid-crystal medium according to claim 6 , wherein the medium comprises one or more compounds selected from the group of compounds of the formulae II-1 to II-3:
in which
R 2 ,
have the meanings given in claim 6 for formula II.
9. The liquid-crystal medium according to claim 6 , wherein the medium comprises one or more compounds selected from the group of compounds of the formulae III-1 to III-6:
in which
R 3 ,
have the meanings given in claim 6 for formula III, and
Z 31 and Z 32 independently of one another, denote trans-CH═CH— or trans-CF═CF—, and in formula III-6 alternatively one of Z 31 and Z 32 may denote —C≡C—.
10. The liquid-crystal medium according to claim 5 , wherein the medium further comprises one or more compounds of formula TA:
in which t is 0 or 1 and R T
have the meanings given for formula T.
11. The liquid-crystal medium according to claim 5 , wherein the medium further comprises one or more chiral compounds.
12. The liquid-crystal medium according to claim 5 , wherein the clearing temperature of the medium is 90° C. or more.
13. A component for high-frequency technology, which comprises the liquid crystal medium according to claim 5 .
14. The component according to claim 13 , 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.
15. A microwave antenna array, which comprises one or more components according to claim 13 .