Electronic switching element

A compound of formula I

• R1-(A1-Z1)r—B1—(Z2-A2)s-Sp-G (I)
• in which
• Sp denotes —O(CF2)p1— or —(CF2)p1—,
• p1 denotes an integer from 1 to 12,
• R1 denotes H, an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH2 groups in these radicals may each be replaced,
• —O—, —S—, —CF2O—, —OCF2—, —CO—O—, or —O—CO—, —SiR0R00—, —NH—, —NR0— or —SO2— 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 be replaced by halogen, CN, SCN or SF5,
• R0, R00, identically or differently, denote an alkyl or alkoxy radical having 1 to 15 C atoms, in which, in addition, one or more H atoms may each be replaced by halogen,
• A1, A2 on each occurrence, identically or differently, denote an aromatic, heteroaromatic, alicyclic or heteroaliphatic ring having 4 to 25 ring atoms, which may also contain condensed rings and which may be mono- or polysubstituted by Y⋅
• Y 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,
• B1
• denotes
• where the groups may be oriented in both directions,
• L1 to L5, independently of one another, denote F, Cl, Br, I, CN, SF5, CF3 or OCF3, where L3 may alternatively also denote H,
• Z1, Z2 on each occurrence, identically or differently, denote a single bond, —CF2O—, —OCF2—, —CF2S—, —SCF2—, —CH2O—, —OCH2—, —C(O)O—, —OC(O)—, —C(O)S—, —SC(O)—, —CH2—, —(CH2)2—, —(CH2)3—, —(CH2)4—, —CF2—, —CF2—CF2—, —CF2—CH2—, —CH2—CF2—, —CH═CH—, —CF═CF—, —CF═CH—, —CH═CF—, —(CH2)3O—, —O(CH2)3—, —C≡C—, —O—, —S—, —C═N—, —N═C—, —N═N—, —N═N(O)—, —N(O)═N— or —N═C—C═N—,
• Sp denotes a spacer group or a single bond,
• G denotes —SO2OH, —OP(O)(OH)2, —PO(OH)2, —C(OH)(PO(OH)2)2, Si(ORx)3 or —SiCl3,
• Rx denotes straight-chain or branched alkyl having 1 to 6 C atoms, and
• r and s, independently of one another, denote 0, 1, 2 or 3,
• where r+s≤4;
• and
• wherein the compound of formula I is mesogenic and has negative dielectric anisotropy.