Compounds and liquid-crystalline medium

A compound of the formula I

• in which
• R11 on each occurrence, independently of one another, denotes H, F, a straight-chain or branched alkyl chain having 1-20 C atoms, in which one —CH2— group or, if present, a plurality of —CH2— groups may be replaced by —O— or —C(═O)—, but two adjacent —CH2— groups cannot be replaced by —O—, and one or, if present, a plurality of —CH2— groups may be replaced by —CH═CH— or —C≡C—, and in which one H atom or a plurality of H atoms may be replaced by F, OR13, N(R13)(R14) or R15,
• R12 on each occurrence, independently of one another, denotes H, a straight-chain or branched alkyl chain having 1-20 C atoms, in which one —CH2— group or a plurality of —CH2— groups may be replaced by —O— or —C(═O)—, but two adjacent —CH2— groups cannot be replaced by —O—, a hydrocarbon radical which contains a cycloalkyl or alkylcycloalkyl unit and in which one —CH2— group or a plurality of —CH2— groups may be replaced by —O— or —C(═O)—, but two adjacent —CH2— groups cannot be replaced by —O—, and in which one H atom or a plurality of H atoms may be replaced by F, OR13, N(R13)(R14) or R15, or an aromatic or heteroaromatic hydrocarbon radical, in which one H atom or a plurality of H atoms may be replaced by OR13, N(R13)(R14) or R15,
• R13 on each occurrence, independently of one another, denotes a straight-chain or branched alkyl or acyl group having 1 to 10 C atoms or an aromatic hydrocarbon or carboxylic acid radical having 6-12 C atoms,
• R14 on each occurrence, independently of one another, denotes a straight-chain or branched alkyl or acyl group having 1 to 10 C atoms or an aromatic hydrocarbon or carboxylic acid radical having 6-12 C atoms,
• R15 on each occurrence, independently of one another, denotes a straight-chain or branched alkyl group having 1 to 10 C atoms, in which one —CH2— group or a plurality of —CH2— groups may be replaced by —O— or —C(═O)—, but two adjacent —CH2— groups cannot be replaced by —O—,
• S11 and S12 on each occurrence, independently of one another, denote an alkylene group having 1 to 20 C atoms, in which one —CH2— group or, if present, a plurality of —CH2— groups may be replaced by —O— or —C(═O)—, but two adjacent —CH2— groups cannot be replaced by —O—, and in which one H atom or a plurality of H atoms may be replaced by F, OR13, N(R13)(R14) or R15, or denote a single bond,
• Y11 to Y14 each, independently of one another, denote methyl or ethyl,
• Z11 to Z14 on each occurrence, independently of one another, denote —O—, —(C═O)—, —O—(C═O)—, —(C═O)—O—, —O—(C═O)—O—, —(N—R13)—, or ˜N—R13—(C═O)—, or additionally a single bond if S11 is a single bond, provided that both Z11 and Z12 do not simultaneously denote —O—, and, provided that, if S12 is a single bond, both Z13 and Z14 do not simultaneously denote —O—, and, provided that if —X11[—R11]o— is a single bond, both Z12 and Z13 do not simultaneously denote —O—,
• X11 denotes C,
• p denotes 1 or 2,
• o for formula I, denotes (3−p), and,
• if p is 2,
• n for formula I, denotes an integer from 2 to 4, and
• m for formula I, denotes (4−n), and,
• if p is 1,
• n for formula I, denotes an integer from 5 to 10, and
• m for formula I, denotes (10−n), and
• denotes an organic radical having (m+n) bonding sites,
• and where, in the case where p=1, —X11[—R11]o— may alternatively also denote a single bond.

A liquid-crystalline medium which comprises:

• one or more compounds of the formulae I-1 to I-9:
• and
• b) one or more compounds selected from the group of the compounds of the formula B,
• in which
• RB1 and RB2 each, independently of one another, denote an unsubstituted alkyl radical, alkoxy radical, oxaalkyl radical or alkoxyalkyl radical having 1 to 7 C atoms, or an alkenyl radical or alkenyloxy radical having 2 to 7 C atoms, and
• LB1 and LB2 each, independently of one another, denote F or Cl.

A liquid-crystalline medium comprising:

• a) one or more compounds of the formula I
• in which
• R11 on each occurrence, independently of one another, denotes H, F, a straight-chain or branched alkyl chain having 1-20 C atoms, in which one —CH2— group or, if present, a plurality of —CH2— groups may be replaced by —O— or —C(═O)—, but two adjacent —CH2— groups cannot be replaced by —O—, and one or, if present, a plurality of —CH2— groups may be replaced by —CH═CH— or —C≡C—, and in which one H atom or a plurality of H atoms may be replaced by F, OR3, N(R13)(R14) or R15,
• R12 on each occurrence, independently of one another, denotes H, a straight-chain or branched alkyl chain having 1-20 C atoms, in which one —CH2— group or a plurality of —CH2— groups may be replaced by —O— or —C(═O)—, but two adjacent —CH2— groups cannot be replaced by —O—, a hydrocarbon radical which contains a cycloalkyl or alkylcycloalkyl unit and in which one —CH2— group or a plurality of —CH2— groups may be replaced by —O— or —C(═O)—, but two adjacent —CH2— groups cannot be replaced by —O—, and in which one H atom or a plurality of H atoms may be replaced by F, OR13, N(R13)(R14) or R15, or an aromatic or heteroaromatic hydrocarbon radical, in which one H atom or a plurality of H atoms may be replaced by OR13, N(R13)(R14) or R15,
• R13 on each occurrence, independently of one another, denotes H, a straight-chain or branched alkyl or acyl group having 1 to 10 C atoms or an aromatic hydrocarbon or carboxylic acid radical having 6-12 C atoms,
• R14 on each occurrence, independently of one another, denotes H, a straight-chain or branched alkyl or acyl group having 1 to 10 C atoms or an aromatic hydrocarbon or carboxylic acid radical having 6-12 C atoms,
• R15 on each occurrence, independently of one another, denotes a straight-chain or branched alkyl group having 1 to 10 C atoms, in which one —CH2— group or a plurality of —CH2— groups may be replaced by —O— or —C(═O)—, but two adjacent —CH2— groups cannot be replaced by —O—,
• S11 and S12 on each occurrence, independently of one another, denote an alkylene group having 1 to 20 C atoms, in which one —CH2— group or, if present, a plurality of —CH2— groups may be replaced by —O— or —C(═O)—, but two adjacent —CH2— groups cannot be replaced by —O—, and in which one H atom or a plurality of H atoms may be replaced by F, OR13, N(R13)(R14) or R15, or denote a single bond,
• Y11 to Y14 each, independently of one another, denote methyl or ethyl,
• Z11 to Z14 on each occurrence, independently of one another, denote —O—, —(C═O)—, —O—(C═O)—, —(C═O)—O—, —O—(C═O)—O—, —(N—R13)—, or ˜N—R13—(C═O)—, or additionally a single bond if S11 is a single bond, provided that both Z11 and Z12 do not simultaneously denote —O—, and, provided that, if S12 is a single bond, both Z13 and Z14 do not simultaneously denote —O—, and, provided that if —X11[—R11]o— is a single bond, both Z12 and Z13 do not simultaneously denote —O—,
• X11 denotes C,
• O. denotes an oxide radical,
• p denotes 1 or 2,
• o for formula I, denotes (3−p), and,
• if p is 2,
• n for formula I, denotes an integer from 2 to 4, and
• m for formula I, denotes (4−n), and,
• if p is 1,
• n for formula I, denotes an integer from 3 to 10, and
• m for formula I, denotes (10−n),
• provided that either:
• p=1 and n denotes an integer from 5 to 8, or
• p=2 and n denotes an integer from 2 to 3, and
• denotes an organic radical having (m+n) bonding sites,
• and where, in the case where p=1, —X11[—R11]o— may alternatively also denote a single bond, and
• b) one or more compounds selected from the group of the compounds of the formula B,
• in which
• RB1 and RB2 each, independently of one another, denote an unsubstituted alkyl radical, alkoxy radical, oxaalkyl radical or alkoxyalkyl radical having 1 to 7 C atoms, or an alkenyl radical or alkenyloxy radical having 2 to 7 C atoms, and
• LB1 and LB2 each, independently of one another, denote F or Cl.