Organic electroluminescent device

A compound of formulae (27), (27a), or (28)

• wherein
• B is a boron atom;
• X is, identically or differently on each occurrence, OR2, SR2, N(R2)2, NHR2, or OBAr2;
• Y is, identically or differently on each occurrence, Ar or X;
• Ar is, identically or differently on each occurrence, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms optionally substituted by one or more R1;
• Ar1 is, identically or differently on each occurrence, an aryl or heteroaryl group having 5 to 40 aromatic ring atoms, which may be substituted by R1;
• R1 is, identically or differently on each occurrence, F, Cl, Br, I, CN, a straight-chain alkyl, alkoxy, or thioalkoxy chain having up to 40 C atoms optionally substituted by R3, or a branched or cyclic alkyl, alkoxy, or thioalkoxy chain having 3 to 40 C atoms, optionally substituted by R3, wherein one or more non-adjacent C atoms of said straight-chain, branched, or cyclic alkyl, alkoxy, or thioalkoxy chain is optionally replaced by N—R3, O, S, CO, O—CO—O,CO—O, —CR3═CR3—, or —C≡C—and wherein one or more H atoms of said straight-chain, branched, or cyclic alkyl, alkoxy, or thioalkoxy chain is optionally replaced by F, Cl, Br, I, CN, or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms optionally substituted by one or more R3, or a combination of two, three or four of these systems;
• and wherein two or more R1 optionally define a mono- or polycyclic, aliphatic, or aromatic ring system;
• R3 is, identically or differently on each occurrence, H or an aliphatic or aromatic hydrocarbon radical having up to 20 C atoms.
• v is, identically or differently on each occurrence, 0 or 1;
• Z is, identically or differently on each occurrence, O, S, NR2, or NH;
• L is, identically or differently on each occurrence, an organic group having 4 to 60 C atoms, to which at least four groups Z are bonded in such a way that they are able, with the boron atom, to form a cyclic system;
• R2 is, identically or differently on each occurrence, a straight-chain alkyl chain having up to 40 C atoms optionally substituted by R3 or a branched or cyclic alkyl chain having 3 to 40 C atoms optionally substituted by R3;
• wherein one or more non-adjacent C atoms is optionally replaced by N—R3, O, S, CO, O—CO—O, CO—O, —CR3═CR3—, or —C≡C—with the proviso that a heteroatom is not bonded directly to the oxygen or sulfur or nitrogen of the group X or Y;
• and wherein one or more H atoms is optionally replaced by F, Cl, Br, I, CN, or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms optionally substituted by one or more radicals R3, or a combination of two, three or four of these systems;
• and wherein two or more radicals R2 optionally define a mono- or polycyclic, aliphatic, or aromatic ring system;
• Ar2 is, identically or differently on each occurence, a fused aryl or heteroaryl group having 9 to 20 C atoms;
• Ar3 is, identically or differently on each occurence, a flourene or spirobiflourene group optionally substituted by R1;
• Q is, identically or differently on each occurrence, a divalent unit selected from Ar, O, S, SO, SO2, Se, SeO, SeO2, Te, TeO, TeO2, NAr, PAr, P(═O)Ar, AsAr, As(═O)Ar, SbAr, Sb(═O)Ar, C(R1)2, C═O, Si(R1)2, and O—BAr—O;
• p is, identically or differently on each occurrence, 1, 2, 3, 4, 5, or 6;
• is 0 or 1;
• t is 1, 2, 3, 4, or 5;
• w is, identically or differently on each occurrence, 1, 2, 3, 4, 5, or 6;
• with the proviso that Ar2 in formula (27) is not naphthyl on each occurrence if all p equal 1 and at the same time s equals 0 and t equals 1, and with the proviso that boronic acid esters of formula (28) formed with pinacol, 1,2-ethanediol, 2,2-dimethyl-1,3-propanediol, 2,3-butanediol, and isopropanol are excluded.