Liquid-crystalline medium

A liquid-crystalline medium comprising:

• at least one compound of formula I,
• in which
• R1 and
• R1* each, independently of one another, denote an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH2 groups in these radicals may each optionally be replaced, independently of one another, by —C≡C—, —CF2O—, —CH═CH—,
• —O—, —CO—O—, —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 each optionally be replaced by halogen,
• Z1 and Z2 each, independently of one another, denote a single bond, —CH2CH2—, —CH═CH—, —CH2O—, —OCH2—, —CF2O—, —OCF2—, —COO—, —OCO—, —C2F4—, —C≡C—, —CF═CF—, or —CH═CHCHO—, and
• L1-3 each, independently of one another, denote F, Cl, CF3, OCF3 or CHF2;
• and
• at least one compound selected from formulas IIA-13 to IIA-31, IIA-44 to IIA-52, IIB-7 to IIB-10, L-1 to L-11, T-1 to T-12, T-14 to T-21, BC, CR, PH-1, PH-2, BF-1, BF-2, BS-1, BS-2, O-6, P-1 to P-4, Z-1 to Z-9, and B-1a:
• wherein
• alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms,
• alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms, and
• (O) denotes a single bond or —O—;
• wherein
• R, R1 and R2 each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, or monosubstituted by CN or CF3 or at least monosubstituted by halogen, where, in addition, one or more CH2 groups in these radicals may each optionally be replaced by —O—, —S—,
• —C≡C—, —CF2O—, —OCF2—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another,
• (O) denotes a single bond or —O—,
• alkyl denotes an alkyl radical having 1-6 C atoms, and
• s denotes 1 or 2;
• wherein
• R denotes a straight-chain alkyl or alkoxy radical having 1-7 C atoms or alkenyl having 2-6 C atoms,
• (O) denotes a single bond or —O—,
• m=0, 1, 2, 3, 4, 5 or 6, and
• n denotes 0, 1, 2, 3 or 4;
• wherein
• RB1, RB2, RCR1, RCR2, R1, R2 each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, or monosubstituted by CN or CF3 or at least monosubstituted by halogen, where, in addition, one or more CH2 groups in these radicals may each optionally be replaced by —O—, —S—,
• —C≡C—, —CF2O—, —OCF2—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another,
• c is 0, 1 or 2, and
• d is 1 or 2;
• wherein
• R1 and R2 each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, or monosubstituted by CN or CF3 or at least monosubstituted by halogen, where, in addition, one or more CH2 groups in these radicals may each optionally be replaced by —O—, —S—,
• —C≡C—, —CF2O—, —OCF2—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another;
• wherein
• R denotes straight-chain alkyl, alkoxy or alkenyl, each having up to 6 C atoms respectively, and
• X denotes F, Cl, CF3, OCF3, OCHFCF3 or CCF2CHFCF3;
• in which
• R denotes H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, or monosubstituted by CN or CF3 or at least monosubstituted by halogen, where, in addition, one or more CH2 groups in these radicals may each optionally be replaced by —O—, —S—,
• —C≡C—, —CF2O—, —OCF2—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another,
• (O) denotes a single bond or —O—, and
• alkyl denotes an alkyl radical having 1-6 C atoms;
• wherein
• alkyl* denotes an alkyl radical having 1 6 C atoms.