Heteroaromatic isothiocyanates

A liquid-crystal medium comprising:

• one or more compounds of formula N
• in which
• RN denotes H, alkyl or alkoxy having 1 to 12 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 12 C atoms, in which one or more CH2-groups may be replaced by,
• or denotes a group RP,
• RP denotes halogen, CN, NCS, RF, RF—O—, or RF—S—, wherein RF denotes fluorinated alkyl having 1 to 9 C atoms or fluorinated alkenyl having 2 to 9 C atoms,
• ZN1 and ZN2, identically or differently, denote —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —C≡C—C≡C—, or a single bond,
• W denotes N, C—F or C—Cl,
• X1 and X2, identically or differently, denote H, Cl, F, methyl, or ethyl,
• on each occurrence, identically or differently, denote a radical selected from:
• a) the group consisting of 1,4-phenylene, 1,4-naphthylene, and 2,6-naphthylene, in which one or two CH groups may each be replaced by N and in which one or more H atoms may each be replaced by L,
• b) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, bicyclo[1.1.1]pentane-1,3-diyl, 4,4′-bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl, and spiro[3.3]heptane-2,6-diyl, in which one or more non-adjacent CH2 groups may each be replaced by —O— or —S— and in which one or more H atoms may each be replaced by F, and
• c) the group consisting of thiophene-2,5-diyl, thieno[3,2-b]thiophene-2,5-diyl and selenophene-2,5-diyl, each of which may be mono- or polysubstituted by L,
• L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF5, or straight-chain, in each case optionally fluorinated, alkyl having 1 to 12 C atoms, alkoxy having 1 to 12 C atoms, alkylcarbonyl having 2 to 12 C atoms, alkoxycarbonyl having 2 to 12 C atoms, alkylcarbonyloxy having 2 to 12 C atoms, or alkoxycarbonyloxy having 2 to 12 C atoms, or branched, in each case optionally fluorinated, alkyl having 3 to 12 C atoms, alkoxy having 3 to 12 C atoms, alkylcarbonyl having 4 to 12 C atoms, alkoxycarbonyl having 4 to 12 C atoms, alkylcarbonyloxy having 4 to 12 C atoms, or alkoxycarbonyloxy having h to 12 C atoms, and
• n is 0, 1 or 2;
• and
• one or more compounds selected from the group of compounds consisting of the compounds of formulae I, II and III,
• in which
• R1 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 CH2-groups may each be replaced by,
• n is 0, 1 or 2,
• on each occurrence, independently of one another, denote
• in which RL, on each occurrence identically or differently, denotes H or alkyl having 1 to 6 C atoms,
• and wherein
• alternatively denotes
• R2 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 CH2-groups may each be replaced by,
• Z21 denotes trans-CH═CH—, trans-CF═CF— or —C≡C—, and
• independently of one another, denote
• in which RL, on each occurrence identically or differently, denotes H or alkyl having 1 to 6 C atoms;
• R3 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 CH2-groups may each be replaced by,
• one of Z31 and Z32, denotes trans-CH═CH—, trans-CF═CF—, or —C≡C— and the other one, independently thereof, denotes —C≡C—, trans-CH═CH—, trans-CF═CF—, or a single bond, and
• independently of one another, denote
• in which RL, on each occurrence identically or differently,
• denotes H or alkyl having 1 to 6 C atoms,
• and wherein
• alternatively denotes