Materials for organic electroluminescent devices

A compound of formula (1)

• where the symbols used are as follows:
• Y is O or S;
• Z is the same or different at each instance and is CR or N, with the proviso that at least two Z are N;
• Ar1 is the same or different at each instance and is an aromatic ring system which has 6 to 40 aromatic ring atoms and may be substituted by one or more R radicals, or a heteroaromatic ring system containing at least one nitrogen atom which has 5 to 40 aromatic ring atoms and which is bonded to the dibenzofuran or dibenzothiophene via the at least one nitrogen atom and which may be substituted by one or more R radicals, or a dibenzofuran or dibenzothiophene group which may be substituted by one or more R radicals;
• Ar2 is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted by one or more R radicals;
• R is the same or different at each instance and is H, D, F, Cl, Br, I, N(Ar′)2, N(R1)2, OAr′, SAr′, CN, NO2, OR1, SR1, COOR1, C(═O)N(R1)2, Si(R1)3, B(OR1)2, C(═O)R1, P(═O)(R1)2, S(═O)R1, S(═O)2R1, OSO2R1, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R1 radicals, where one or more nonadjacent CH2 groups may be replaced by Si(R1)2, C↑O, NR1, O, S or CONR1, or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms, preferably 5 to 40 aromatic ring atoms, and may be substituted in each case by one or more R1 radicals;
• at the same time, two R radicals together may also form a ring system;
• Ar′ is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted by one or more R1 radicals;
• at the same time, two Ar′ radicals bonded to the same nitrogen atom may also be bridged to one another by a single bond or a bridge selected from N(R1), C(R1)2, O and S;
• R is the same or different at each instance and is H, D, F, Cl, Br, I, N(R2)2, CN, NO2, OR2, SR2, Si(R2)3, B(OR2)2, C(═O)R2, P(═O)(R2)2, S(═O)R2, S(═O)2R2, OSO2R2, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may each be substituted by one or more R2 radicals, where one or more nonadjacent CH2 groups may be replaced by Si(R2)2, C═O, NR2, O, S or CONR2 and where one or more hydrogen atoms in the alkyl, alkenyl or alkynyl group may be replaced by D, F, Cl, Br, I or CN, or an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more R2 radicals;
• at the same time, two or more R1 radicals together may form an aliphatic ring system;
• R2 is the same or different at each instance and is H, D, F, CN or an aliphatic, aromatic or heteroaromatic organic radical, especially a hydrocarbyl radical, having 1 to 20 carbon atoms, in which one or more hydrogen atoms may also be replaced by F;
• p, q are the same or different at each instance and are 0, 1, 2 or 3;
• r is 0, 1, 2, 3 or 4, with the proviso that r is not more than (4-j);
• S is 0, 1, 2 or 3, with the proviso that s is not more than (3-k);
• j, k are the same or different at each instance and are 0, 1, 2 or 3, with the proviso that j+k≥1.