Liquid-crystalline medium and high-frequency components comprising same

A liquid-crystal medium comprising:

• one or more pleochroic compounds
• one or more compounds selected from the group of compounds of formulae I, II and III
• in which
• L11 denotes R11 or X11,
• L12 denotes R12 or X12,
• R11 and R12, independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 15 C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms,
• X11 and X12, independently of one another, denote H, F, Cl, —CN, —NCS, —SF5, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated or fluorinated alkoxyalkyl having 2 to 7 C atoms, and
• independently of one another, denote
• in which
• L21 denotes R21 and, in the case where Z21 and/or Z22 denote trans-CH═CH— or trans-CF═CF—, alternatively denotes X21,
• L22 denotes R22 and, in the case where Z21 and/or Z22 denote trans-CH═CH— or trans-CF═CF—, alternatively denotes X22,
• R21 and R22, independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17, C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15,
• X21 and X22, independently of one another, denote F or Cl, —CN, —NCS, —SF5, 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,
• one of
• Z21 and Z22 denotes trans-CH═CH—, trans-CF═CF— or —C≡C— and the other, independently thereof, denotes trans-CH═CH—, trans-CF═CF— or a single bond, and
• independently of one another, denote
• in which
• L31 denotes R31 or X31,
• L32 denotes R32 or X32,
• R31 and R32, independently of one another, denote 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,
• X31 and X32, independently of one another, denote H, F, Cl, —CN, —NCS, —SF5, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, unfluorinated or fluorinated alkenyloxy or unfluorinated or fluorinated alkoxyalkyl having 2 to 7 C atoms,
• Z31 to Z33, independently of one another, denote trans-CH═CH—, trans —CF═CF—, —C≡C— or a single bond, and
• independently of one another, denote
• optionally one or more chiral compounds,
• and
• optionally one or more polymerisable compounds of formula P
• Pa—(Spa)s1-(A1-Z1)n1-A2-Q-A3-(Z4-A4)n2-(Spb)s2-Pb P
• wherein the individual radicals have the following meanings:
• Pa, Pb each, independently of one another, are a polymerisable group,
• Spa, Spb each, independently of one another, denote a spacer group,
• s1, s2 each, independently of one another, denote 0 or 1,
• n1, n2 each, independently of one another, denote 0 or 1,
• Q denotes a single bond, —CF2O—, —OCF2—, —CH2O—, —OCH2—, —(CO)O—, —O(CO)—, —(CH2)4—, —CH2—CH2—, —CF2—CF2—, —CF2—CH2—, —CH2—CF2—, —CH═CH—, —CF═CF—, —CF═CH—, —(CH2)3O—, —O(CH2)3—, —CH═CF—, —C≡C—, —O—, —CH2—, —(CH2)3—, or —CF2—,
• Z1, Z4 denote a single bond, —CF2O—, —OCF2—, —CH2O—, —OCH2—, —(CO)O—, —O(CO)—, —(CH2)4—, —CH2—CH2—, —CF2—CF2—, —CF2—CH2—, —CH2—CF2—, —CH═CH—, —CF═CF—, —CF═CH—, —(CH2)3O—, —O(CH2)3—, —CH═CF—, —C≡C—, —O—, —CH2—, —(CH2)3—, —CF2—, where Z1 and Q or Z4 and Q do not simultaneously denote a group selected from —CF2O— and —OCF2—,
• A1, A2, A3, A4
• each, independently of one another, denote a diradical group selected from the following groups:
• a) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene and 1,4′-bicyclohexylene, in which, in addition, one or more non-adjacent CH2 groups may be replaced by —O— and/or —S— and in which, in addition, one or more H atoms may be replaced by F,
• b) the group consisting of 1,4-phenylene and 1,3-phenylene, in which, in addition, one or two CH groups may be replaced by N and in which, in addition, one or more H atoms may be replaced by L,
• c) the group consisting of tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl and selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L,
• d) the group consisting of saturated, partially unsaturated or fully unsaturated, and optionally substituted, polycyclic radicals having 5 to 20 cyclic C atoms, one or more of which may, in addition, be replaced by heteroatoms,
• where, in addition, one or more H atoms in these polycyclic radicals may be replaced by L,
• and A3, alternatively may be a single bond,
• L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms.