Materials for organic electroluminescent devices

A compound of formula (1)

• wherein
• Z is, identically or differently on each occurrence, N, P, As, or P═O;
• X and Y
• are, identically or differently on each occurrence, CR2, C═O, O, S, NR, SiR2, PR, P(═O)R, S(═O), or SO2;
• A is, identically or differently on each occurrence, CR or N;
• Ar1 is, identically or differently on each occurrence, a monovalent aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms optionally substituted by one or more radicals R;
• Ar2 is, identically or differently on each occurrence, a divalent aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms optionally substituted by one or more radicals R;
• R is, identically or differently on each occurrence, H;
• F;
• CI;
• Br;
• I;
• CN;
• NO2;
• Si(R1)3;
• N(R1)2;
• B(OR1)2;
• a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms optionally substituted by one or more radicals R1;
• a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 40 C atoms optionally substituted by one or more radicals R1;
• wherein one or more non-adjacent CH2 groups of said straight-chain alkyl, alkoxy or thioalkoxy groups or said branched or cyclic alkyl, alkoxy or thioalkoxy groups are optionally replaced by —R1C═CR1—, —C═C—, Si(R1)2, Ge(R1)2, Sn(R1)2, C═O, C═S, C═Se, C═NR1, —O—, —S—, —N(R1)— or —CONR1— and wherein one or more H atoms of said straight-chain alkyl, alkoxy or thioalkoxy groups or said branched or cyclic alkyl, alkoxy or thioalkoxy groups are optionally replaced by F, CI, Br, I, CN, or NO2;
• an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms optionally substituted by one or more radicals;
• an aryloxy or heteroaryloxy group having 5 to 24 aromatic ring atoms optionally substituted by one or more radicals;
• or a combination of two, three, four, or five of these systems;
• and wherein two or more substituents R optionally define a mono- or poly cyclic, aliphatic or aromatic ring system with one another;
• R is, identically or differently on each occurrence, H or a hydrocarbon radical having 1 to 20 C atoms, which may be aliphatic or aromatic or a combination of aliphatic and aromatic, wherein one or more H atoms are optionally replaced by F, and wherein two or more radicals R1 optionally define a mono- or polycyclic, aliphatic or aromatic ring system with one another;
• n is 0, 1, 2, or 3;
• m is, identically or differently on each occurrence, 0 or 1, wherein when m=0, Y is not present and instead radicals R are bonded in these positions.