Materials for electronic devices

A compound of a formula (I)

• where the variables that occur are as follows:
• X is O, S or NR2;
• Z is the same or different at each instance and is C—R3 or N;
• Z1 is the same or different at each instance and is selected from C—R1 and C-A;
• Z2 is the same or different at each instance and is selected from C—R1 and C-A;
• where at least one group selected from the Z1 and Z2 groups in formula (I) is C-A;
• A is a group of the following formula:
• where the dashed bond is the bond to the carbon atom of the C-A unit;
• Ar1 is the same or different at each instance and is selected from aromatic ring systems which have 6 to 40 aromatic ring atoms and are substituted by R4 radicals, and heteroaromatic ring systems which have 5 to 40 aromatic ring atoms and are substituted by R4 radicals, where the two Ar1 groups in formula (A) may be bonded to one another via a bond or an E group;
• E is the same or different at each instance and is selected from C(R4)2, —C(R4)2—C(R4)2—, —C(R4)═C(R4)—, C═O, Si(R4)2, NR4, O, S, S═O, and SO2;
• R1 is the same or different at each instance and is selected from H, D, F, Cl, Br, I, C(═O)R5, CN, Si(R5)3, N(R5)2, P(═O)(R5)2, OR5, S(═O)R5, S(═O)2R5, straight-chain alkyl or alkoxy groups having 1 to 20 carbon atoms, branched or cyclic alkyl or alkoxy groups having 3 to 20 carbon atoms, alkenyl or alkynyl groups having 2 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms, and heteroaromatic ring systems having 5 to 40 aromatic ring atoms;
• where two or more R1 radicals may be joined to one another and may form an aromatic ring;
• where said alkyl, alkoxy, alkenyl and alkynyl groups and said aromatic ring systems and heteroaromatic ring systems are each substituted by R5 radicals;
• and where one or more CH2 groups in said alkyl, alkoxy, alkenyl and alkynyl groups may be replaced by —R5═CR5—, —C═C—, Si(R5)2, C═O, C═NR5, —C(═O)O—, —C(═O) NR5—, NR5, P(═O)(R5), —O—, —S—, SO or SO2;
• R2 is selected from straight-chain alkyl groups having 1 to 20 carbon atoms, branched or cyclic alkyl groups having 3 to 20 carbon atoms, alkenyl or alkynyl groups having 2 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms, and heteroaromatic ring systems having 5 to 40 aromatic ring atoms;
• where said alkyl, alkenyl and alkynyl groups and said aromatic ring systems and heteroaromatic ring systems are each substituted by R5 radicals;
• and where one or more CH2 groups in said alkyl, alkenyl and alkynyl groups may be replaced by —R5C═CR5—, —C═C—, Si(R5)2, C═O, C═NR5, —C(═O)O—, —C(═O) NR5—, NR5, P(═O)(R5), —O—, —S—, SO or SO2;
• R3 is the same or different at each instance and is selected from H, D, F, Cl, Br, I, C(═O)R5, CN, Si(R5)3, N(R5)2, P(═O)(R5)2, OR5, S(═O)R5, S(═O)2R5, straight-chain alkyl or alkoxy groups having 1 to 20 carbon atoms, branched or cyclic alkyl or alkoxy groups having 3 to 20 carbon atoms, alkenyl or alkynyl groups having 2 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms, and heteroaromatic ring systems having 5 to 40 aromatic ring atoms;
• where two or more R1 radicals may be joined to one another and may form an aromatic ring;
• where said alkyl, alkoxy, alkenyl and alkynyl groups and said aromatic ring systems and heteroaromatic ring systems are each substituted by R5 radicals;
• and where one or more CH2 groups in said alkyl, alkoxy, alkenyl and alkynyl groups may be replaced by —R5C═CR5—, —C═C—, Si(R5)2, C—O, C═NR5, —C(═O)O—, —C(═O) NR5—, NR5, P(═O)(R5), —O—, —S—, SO or SO2;
• R4 is the same or different at each instance and is selected from H, D, F, Cl, Br, I, C(═O)R5, CN, Si(R5)3, N(R5)2, P(═O)(R5)2, OR5, S(═O)R5, S(═O)2R5, straight-chain alkyl or alkoxy groups having 1 to 20 carbon atoms, branched or cyclic alkyl or alkoxy groups having 3 to 20 carbon atoms, alkenyl or alkynyl groups having 2 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms, and heteroaromatic ring systems having 5 to 40 aromatic ring atoms;
• where two or more R4 radicals may be joined to one another and may form a ring;
• where said alkyl, alkoxy, alkenyl and alkynyl groups and said aromatic ring systems and heteroaromatic ring systems are each substituted by R5 radicals;
• and where one or more CH2 groups in said alkyl, alkoxy, alkenyl and alkynyl groups may be replaced by —R5C═CR5—, —C═C—, Si(R5)2, C═O, C═NR5, —C(═O)O—, —C(═O) NR5—, NR5, P(═O)(R5), —O—, —S—, SO or SO2;
• R5 is the same or different at each instance and is selected from H, D, F, Cl, Br, I, C(═O)R6, CN, Si(R6)3, N(R6)2, P(═O)(R6)2, OR6, S(═O)R6, S(═O)2R6, straight-chain alkyl or alkoxy groups having 1 to 20 carbon atoms, branched or cyclic alkyl or alkoxy groups having 3 to 20 carbon atoms, alkenyl or alkynyl groups having 2 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms, and heteroaromatic ring systems having 5 to 40 aromatic ring atoms;
• where two or more R5 radicals may be joined to one another and may form a ring;
• where said alkyl, alkoxy, alkenyl and alkynyl groups and said aromatic ring systems and heteroaromatic ring systems are each substituted by R6 radicals;
• and where one or more CH2 groups in said alkyl, alkoxy, alkenyl and alkynyl groups may be replaced by —R6C═CR6—, —C═C—, Si(R6)2, C═O, C═NR6, —C(═O)O—, —C(═O) NR6—, NR6, P(═O)(R6), —O—, —S—, SO or SO2;
• R6 is the same or different at each instance and is selected from H, D, F, Cl, Br, I, CN, alkyl or alkoxy groups having 1 to 20 carbon atoms, alkenyl or alkynyl groups having 2 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms and heteroaromatic ring systems having 5 to 40 aromatic ring atoms;
• where two or more R6 radicals may be joined to one another and may form a ring;
• and where said alkyl, alkoxy, alkenyl and alkynyl groups, aromatic ring systems and heteroaromatic ring systems may be substituted by one or more radicals selected from F and CN;
• where, in the case that X=NR2, at least one Z2 group in formula (I) must be C-A.