Materials for electronic devices

1. An organic electroluminescent device comprising at least one compound of the formula (I) as hole-transport material in a hole-transport layer or hole-injection layer or as matrix material in an emitting layer,

where the following applies to the symbols and indices occurring:

X 1 , X 2 and X 3 are on each occurrence, identically or differently, C(R 2 ) 2 , C═O, C═NR 2 , Si(R 2 ) 2 , NR 1 , PR 1 , P(═O)R 1 , O, S, S═O or S(═O) 2 ;

Z is on each occurrence, identically or differently, CR 2 or N, where not more than two adjacent groups Z may simultaneously be equal to N;

R 1 is on each occurrence, identically or differently, C(═O)R 3 , CR 3 ═C(R 3 ) 2 , C(═O)OR 3 , C(═O)NR 3 2 , P(=O)(R 3 ) 2 , OR 3 , S(═O)R 3 , S(═O) 2 R 3 , or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which optionally in each case be substituted by one or more radicals R 3 , or a combination of these systems, where two or more radicals R 1 is optionally linked to one another and may form an aliphatic or aromatic ring;

R 2 is on each occurrence, identically or differently, H, D, F, Cl, Br, I, B(OR 3 ) 2 , CHO, C(═O)R 3 , CR 3 ═C(R 3 ) 2 , CN, C(═O)OR 3 , C(═O)NR 3 2 , Si(R 3 ) 3 , N(R 3 ) 2 , NO 2 , P(═O)(R 3 ) 2 , OS(═O) 2 R 3 , OH, S(═O)R 3 , S(═O) 2 R 3 , a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms, where the above-mentioned groups may each be substituted by one or more radicals R 3 and where one or more non-adjacent CH 2 groups in the above-mentioned groups is optionally replaced by —R 3 C=CR 3 —, —C≡C—, Si(R 3 ) 2 , Ge(R 3 ) 2 , Sn(R 3 ) 2 , C═O, C═S, C═Se, C═NR 3 , —C(═O)O—, —C(═O)NR 3 —, NR 3 , P(═O)(R 3 ), —O—, —S—, S═O or S(═O) 2 and where one or more H atoms in the above-mentioned groups is optionally replaced by D, F, Cl, Br, I, CN or NO 2 , or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R 3 , or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which is optionally substituted by one or more radicals R 3 , or a combination of these systems, where two or more radicals R 2 is optionally linked to one another and may form an aliphatic or aromatic ring;

R 3 is on each occurrence, identically or differently, H, D, F, Cl, Br, I, B(OR 4 ) 2 , CHO, C(═O)R 4 , CR 4 ═C(R 4 ) 2 , CN, C(═O)OR 4 , C(═O)NR 4 2 , Si(R 4 ) 3 , N(R 4 ) 2 , NO 2 , P(═O)(R 4 ) 2 , OS(═O) 2 R 4 , OH, S(═O)R 4 , S(═O) 2 R 4 , a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms, where the above-mentioned groups may each be substituted by one or more radicals R 4 and where one or more non-adjacent CH 2 groups in the above-mentioned groups is optionally replaced by —R 4 C═CR 4 —, —C≡C—, Si(R 4 ) 2 , Ge(R 4 ) 2 , Sn(R 4 ) 2 , C═O, C═S, C═Se, C═NR 4 , —C(═O)O—, —C(═O)NR 4 —, NR 4 , P(═O)(R 4 ), —O—, —S—, S═O or S(═O) 2 and where one or more H atoms in the above-mentioned groups is optionally replaced by D, F, Cl, Br, I, CN or NO 2 , or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R 4 , or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which is optionally substituted by one or more radicals R 4 , or a combination of these systems, where two or more radicals R 3 is optionally linked to one another and may form an aliphatic or aromatic ring;

R 4 is, identically or differently on each occurrence, H, D, F or an aliphatic, aromatic and/or heteroaromatic organic radical having 1 to 20 C atoms, in which, in addition, one or more H atoms is optionally replaced by D or F; two or more substituents R 4 here may also be linked to one another and form an aliphatic or aromatic ring; and

n has a value of 0, 1 or 2;

where the case where all groups X 1 , X 2 and X 3 are identical is excluded.

2. The device according to claim 1 , wherein n is equal to 0 or 1.

3. The device according to claim 1 , wherein at least one of the groups X 1 , X 2 and X 3 represents a group NR 1 .

4. The device according to claim 1 , wherein 0, 1 or 2 groups Z per aromatic or heteroaromatic six-membered ring are equal to N.

5. The device according to claim 1 , wherein the groups X 1 , X 2 and X 3 are selected, identically or differently, from C(R 2 ) 2 , C═O, Si(R 2 ) 2 , NR 1 , PR 1 , P(═O)R 1 , O and S.

6. The device according to claim 1 , wherein R 1 represents on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which optionally in each case be substituted by one or more radicals R 3 .

7. The device according to claim 1 , wherein at least one group is present as substituent R 1 or R 2 which is selected from electron-deficient heteroaryl groups, aromatic or heteroaromatic ring systems having 10 to 30 aromatic ring atoms and from arylamine groups, each of which is optionally substituted by one or more radicals as defined in claim 1 .

8. The device according to claim 1 , wherein the compound of formula (I) conforms to the compounds of one of the following formulae

groups Z and R 1 are as defined in claim 1 .

9. A process for the preparation of the compound of the formula (I) as defined in claim 1 which comprises ring-closure reacting one or more condensed heteroaromatic five-membered rings.

10. An oligomer, polymer or dendrimer comprising one or more compounds of the formula (I) as defined in claim 1 , where the bond(s) to the polymer, oligomer or dendrimer is optionally localised at any position in formula (I) substituted by R 1 or R 2 .

11. A formulation comprising at least one compound of the formula (I) as defined in claim 1 and at least one solvent.

12. A formulation comprising at least one one polymer, oligomer or dendrimer according to claim 10 and at least one solvent.

13. An organic electroluminescent device which comprises the polymer, oligomer or dendrimer according to claim 10 is employed as hole-transport material in a hole-transport layer or hole-injection layer and/or is employed as matrix material in an emitting layer and/or as electron-transport material in an electron-transport layer.