Cyclic nitrogen compounds for organic electroluminescent devices

Abstract

The present invention relates to cyclic nitrogen compounds which are suitable for use in electronic devices, and to electronic devices, in particular organic electroluminescent devices containing said cyclic nitrogen compounds.

Description

[0001] CYCLIC NITROGEN COMPOUNDS FOR ORGANIC ELECTROLUMINESCENT DEVICES

[0002] The present invention relates to cyclic nitrogen compounds for use in electronic devices, in particular in organic electroluminescent devices, and to electronic devices, in particular organic electroluminescent devices, containing these materials.

[0003] Electronic devices containing organic compounds are widely known and commercially available. These devices can, for example, each comprise one or more hole-injection layers, hole-transport layers, hole-blocking layers, electron-transport layers, electron-injection layers, exciton-blocking layers, electron-blocking layers, and / or charge-generation layers. In general, there is a need for improvement regarding the properties of these devices, with the compounds used in the previously described layers having a particularly significant influence on the properties of the devices.

[0004] Furthermore, phosphorescent organometallic complexes are frequently used as emitting materials in organic electroluminescent devices. For quantum mechanical reasons, up to four times the energy and power efficiency is possible when using organometallic compounds as phosphorescent emitters. In general, there is still room for improvement in electroluminescent devices, especially in electroluminescent devices that exhibit triplet emission (phosphorescence). The properties of phosphorescent electroluminescent devices are not only determined by the triplet emitters used. The other materials used, such as matrix materials, are also of particular importance. Improvements to these materials can therefore also lead to significant improvements in the properties of the electroluminescent devices.Similar statements also apply to organic electroluminescent devices based on fluorescent emitters or emitters exhibiting TADF (thermally activated delayed fluorescence).

[0005] Documents WO 2021 / 230653 A1, EP 3885350 A1, EP 4123735 A1, and WO 2021 / 230653 A1 disclose heterocycles that can be used in organic electroluminescent devices. Compounds according to the present invention that can be used as matrix materials or as hole-transport materials are not disclosed.

[0006] In general, there is still room for improvement in these materials, for example for use as matrix materials and / or hole transport materials, particularly with regard to efficiency and operating voltage, but also with regard to the lifetime of the device.

[0007] The object of the present invention is therefore to provide compounds which are suitable for use in an organic electronic device, in particular in an organic electroluminescent device, and which, when used in this device, lead to good device properties, as well as to provide the corresponding electronic device.

[0008] In particular, the object of the present invention is to provide compounds that result in a long lifetime, good efficiency, and low operating voltage. The properties of the matrix materials, in particular, have a significant influence on the lifetime and efficiency of the organic electroluminescent device.

[0009] A further object of the present invention can be seen in providing compounds suitable for use in phosphorescent or fluorescent electroluminescent devices, in particular as matrix materials. In particular, it is an object of the present invention to provide matrix materials suitable for blue, green, yellow, and red phosphorescent electroluminescent devices, in particular for blue phosphorescent electroluminescent devices.

[0010] Furthermore, the compounds, especially when used as matrix materials or as hole transport materials in organic electroluminescent devices, should lead to devices that exhibit excellent lifetime and efficiency.

[0011] Another task can be seen in providing electronic devices with excellent performance as cost-effectively as possible and in consistent quality

[0012] Furthermore, the electronic devices should be able to be used or adapted for a variety of purposes. In particular, the performance of the electronic devices should be maintained over a wide temperature range.

[0013] Surprisingly, it has been found that certain compounds, described in more detail below, achieve this objective, are well suited for use in electroluminescent devices, and lead to organic electroluminescent devices that exhibit very good properties, particularly with regard to lifetime, color purity, efficiency, and operating voltage. These compounds, as well as electronic devices, in particular organic electroluminescent devices, containing such compounds, are therefore the subject of the present invention.

[0014] The present invention relates to a compound comprising at least one structure of formula (I), preferably a compound according to formula (I),

[0015] Formula (I) where the symbols are:

[0016] Z represents, the same or different at each occurrence, C(R a ), Si(R b ) or Ge(R b ), preferably for C(Ra ) or Si(R b ) and particularly preferably for C(R a );

[0017] W 1 represents, in each occurrence, the same or different, a group - C(R C ) 2-, -C(R C ) 2-C(R C )2- or -C(R C )2-C(R c )2-C(R c )2-;

[0018] W 2 represents, in each occurrence, the same or different, a group - C(R d ) 2-, -C(R d ) 2-C(R d )2- or -C(R d )2-C(R c )2-C(R d )2-;

[0019] X represents, identically or differently at each occurrence, N or C(R), preferably C(R), with the proviso that not more than two of the groups X in a cycle represent N;

[0020] RH, D, OH, F, CI, Br, I, CN, NO2, N(Ar)2, N(R e )2, C(=O)N(Ar)2, C(=O)N(R e )2, C(Ar)3, C(R e )3, Si(Ar)3, Si(R e )3, Ge(Ar)3, Ge(R e )3, B(Ar)2, B(R e)2, C(=O)Ar, C(=O)R e , P(=O)(Ar)2, P(=O)(R e )2, P(Ar)2, P(R e )2, S(=O)Ar, S(=O)R e , S(=O)2Ar, S(=O)2R e , OSO2Ar, OSO2R e , a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 C atoms, wherein the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group is each substituted by one or more radicals R e may be substituted, wherein one or more non-adjacent CH2 groups are substituted by R e C=CR e , C=C, Si(R e )2, C=O, C=S, C=Se, C=NR e , -C(=O)O-, -C(=O)NR e -, NR e , P(=O)(R e ), -O-, -S-, SO or SO2, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each of which is substituted by one or more radicals R emay be substituted, or an arylalkyl or heteroarylalkyl group having 5 to 60 aromatic ring atoms and 1 to 10 C atoms in the alkyl radical, which may be substituted by one or more radicals R e may be substituted; two radicals R may also be substituted with each other or at least one radical R may be substituted with another group, preferably R c or R d form a ring system;

[0021] Ar is at each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which is substituted by one or more radicals R e may be substituted, whereby two radicals Ar which bind to the same C-atom, Si-atom, N-atom, P-atom or B-atom may also be connected by a single bond or a bridge selected from B(R e ), C(R e )2, Si(R e )2, C=O, C=NR e , C=C(R e )2, O, S, S=O, SO2, N(R e ), P(R e ) and P(=O)R e , be bridged together;

[0022] R a is, at each occurrence, identically or differently, H, D, a straight-chain alkyl group having 1 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, where the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group is each substituted by one or more radicals R 1 may be substituted, wherein one or more non-adjacent CH2 groups are substituted by R 1 C=CR 1 , C=C, Si(R 1 )2, NR 1 , -O- or -S-, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each of which is substituted by one or more radicals R 1 may be substituted; a radical R a with another group, preferably R c or R d form an aliphatic or heteroaliphatic ring system;

[0023] R bis at each occurrence, identically or differently, H, D, a straight-chain alkyl group having 1 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, where the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group is each substituted by one or more radicals R 1 may be substituted, wherein one or more non-adjacent CH2 groups are substituted by R 1 C=CR 1 , C=C, Si(R 1 )2, NR 1 , -O- or -S-, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each of which is substituted by one or more radicals R 1 may be substituted; a radical R b with another group, preferably R c or R d form an aliphatic or heteroaliphatic ring system;

[0024] R cis, at each occurrence, identically or differently, H, D, a straight-chain alkyl group having 1 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, where the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group is each substituted by one or more radicals R 1 may be substituted, wherein one or more non-adjacent CH2 groups are substituted by R 1 C=CR 1 , C=C, Si(R 1 )2, NR 1 , -O- or -S-, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each of which is substituted by one or more radicals R 1 can be substituted; two radicals R c also with each other or at least one residue R c with another group, preferably R or R e form an aliphatic or heteroaliphatic ring system;

[0025] R dis, at each occurrence, identically or differently, H, D, a straight-chain alkyl group having 1 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, where the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group is each substituted by one or more radicals R 1 may be substituted, wherein one or more non-adjacent CH2 groups are substituted by R 1 C=CR 1 , C=C, Si(R 1 )2, NR 1 , -O- or -S-, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each of which is substituted by one or more radicals R 1 can be substituted; two radicals R d also with each other or at least one residue R d with another group, preferably R or R e form an aliphatic or heteroaliphatic ring system; R eis, at each occurrence, the same or different: H, D, OH, F, Cl, Br, I, CN, NO2, N(Ar')2, N(R 1 )2, C(=O)N(Ar')2, C(=O)N(R 1 )2, C(Ar')3, C(R 1 )3, Si(Ar')3, Si(R 1 )3, Ge(Ar')3, Ge(R 1 )3, B(Ar')2, B(R 1 )2, C(=O)Ar', C(=O)R 1 , P(=O)(Ar')2, P(=O)(R 1 )2, P(Ar')2, P(R 1 )2, S(=O)Ar', S(=O)R 1 , S(=O)2Ar', S(=O)2R 1 , OSO2Ar', OSO2R 1 , a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 C atoms, wherein the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group is each substituted by one or more radicals R 1 may be substituted, wherein one or more non-adjacent CH2 groups are substituted by R 1 C=CR 1 , C≡C, Si(R 1 )2, Ge(R 1 )2, C=O, C=S, C=Se, C=NR1 , -C(=O)O-, -C(=O)NR 1 -, NR 1 , P(=O)(R 1 ), -O-, -S-, SO or SO2, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each of which is substituted by one or more radicals R 1 may be substituted, or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R 1 can be substituted; two radicals R e also with each other or at least one radical R e with another group, preferably R c or R d form a ring system; Ar' is at each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which is reacted with one or more radicals R 1may be substituted, whereby two radicals Ar' which bind to the same C-atom, Si-atom, N-atom, P-atom or B-atom may also be connected by a single bond or a bridge selected from B(R 1 ), C(R 1 )2, Si(R 1 )2, C=O, C=NR 1 , C=C(R 1 )2, O, S, S=O, SO2, N(R 1 ), P(R 1 ) and P(=O)R 1 , be bridged together; R 1 is, at each occurrence, the same or different: H, D, F, Cl, Br, I, CN, NO2, N(Ar'')2, N(R 2 )2, C(=O)Ar'', C(=O)R 2 , P(=O)(Ar'')2, P(Ar'')2, B(Ar'')2, B(R 2 )2, C(Ar'')3, C(R 2 )3, Si(Ar'')3, Si(R 2 )3, Ge(Ar'')3, Ge(R 2 )3, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 40 C atoms or an alkenyl group having 2 to 40 C atoms, each of which is substituted by one or more radicals R 2may be substituted, with one or more non-adjacent CH2 groups being replaced by -R 2 C=CR 2 -, -C≡C-, Si(R 2 )2, Ge(R 2 )2, C=O, C=S, C=Se, C=NR 2 , -C(=O)O-, -C(=O)NR 2 -, NR 2 , P(=O)(R 2 ), -O-, -S-, SO or SO2 and where one or more H atoms can be replaced by D, F, Cl, Br, I, CN or NO2, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each of which is substituted by one or more radicals R 2 may be substituted, or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R 2 may be substituted, or an aralkyl or heteroaralkyl group having 5 to 60 aromatic ring atoms which may be substituted with one or more radicals R 2 may be substituted, or a combination of these systems; two or more, preferably adjacent, radicals R1 form a ring system, whereby one or more residues R 1 form a ring system with another part of the compound; Ar'' is at each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which with one or more radicals R 2 may be substituted, whereby two radicals Ar'' which bind to the same C-atom, Si-atom, N-atom, P-atom or B-atom may also be connected by a single bond or a bridge selected from B(R 2 ), C(R 2 )2, Si(R 2 )2, C=O, C=NR 2 , C=C(R 2 )2, O, S, S=O, SO2, N(R 2 ), P(R 2 ) and P(=O)R 2 , be bridged together; R 2is selected, identically or differently at each occurrence, from the group consisting of H, D, F, CN, an aliphatic hydrocarbon radical having 1 to 20 C atoms or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, in which one or more H atoms may be replaced by D, F, CI, Br, I or CN and which may be substituted by one or more alkyl groups each having 1 to 4 carbon atoms, where two or more, preferably adjacent, substituents R 2form a ring system with each other; wherein the structure of formula (I) does not comprise a six-membered ring in which a boron atom is arranged in the para-position to a nitrogen atom, and compounds with the CAS numbers CAS 1187049-34-8, CAS 1644382-05-7, CAS 1187049-50-8, CAS 1187049-48-4, CAS 1187049-54-2, CAS 1187049-57-5, CAS 1187049-56-4, CAS 1187049-46-2, CAS 1187049-52-0, CAS 941598-79-4, CAS 136638-71-6, CAS 2576721-78-1, CAS 2241934-41-6, CAS 1211481-23-0, CAS 1211481-22-9, CAS 1211481-21-8, CAS 1211481-11-6, CAS 1211481-14-9, CAS 1211481-13-8, CAS 2429897-27-6, CAS 2738960-82-0, CAS 2429897-26-5, CAS 2576721-65-6 CAS 2290579-28-9 and CAS 2429897-25-4 are exempt from protection.

[0026] The compounds with the above mentioned CAS numbers, which are

[0027]

[0028] Furthermore, in a preferred embodiment, the compound may not comprise a boron atom. Furthermore, the compound may not be ionically charged and / or may not be a salt.

[0029] An aryl group within the meaning of this invention contains 6 to 40 C atoms; a heteroaryl group within the meaning of this invention contains 3 to 40 C atoms and at least one heteroatom, with the proviso that the sum of C atoms and heteroatoms is at least 5. The heteroatoms are preferably selected from N, O and / or S. An aryl group or heteroaryl group is understood to be either a simple aromatic cycle, i.e. benzene, or a simple heteroaromatic cycle, for example pyridine, pyrimidine, thiophene, etc., or a condensed (fused) aryl or heteroaryl group, for example naphthalene, anthracene, phenanthrene, quinoline, isoquinoline, etc. Aromatics linked to one another by a single bond, such as biphenyl, are not referred to as aryl or heteroaryl groups, but as an aromatic ring system.

[0030] An electron-deficient heteroaryl group within the meaning of the present invention is a heteroaryl group that has at least one heteroaromatic six-membered ring with at least one nitrogen atom. Further aromatic or heteroaromatic five-membered rings or six-membered rings can be fused to this six-membered ring. Examples of electron-deficient heteroaryl groups are pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, quinazoline, or quinoxaline. An aromatic ring system within the meaning of this invention contains 6 to 60 C atoms in the ring system. A heteroaromatic ring system within the meaning of this invention contains 3 to 60 C atoms and at least one heteroatom in the ring system, with the proviso that the sum of C atoms and heteroatoms is at least 5. The heteroatoms are preferably selected from N, O, and / or S.An aromatic or heteroaromatic ring system within the meaning of this invention is understood to mean a system that does not necessarily contain only aryl or heteroaryl groups, but in which several aryl or heteroaryl groups can also be connected by a non-aromatic unit, such as a C, N, or O atom. For example, systems such as fluorene, 9,9'-spirobifluorene, 9,9-diarylfluorene, triarylamine, diaryl ether, stilbene, etc. are also understood to be aromatic ring systems within the meaning of this invention, as are systems in which two or more aryl groups are connected, for example, by a short alkyl group. The aromatic ring system is preferably selected from fluorene, 9,9'-spirobifluorene, 9,9-diarylamine, or groups in which two or more aryl and / or heteroaryl groups are linked to one another by single bonds.

[0031] In the context of the present invention, an aliphatic hydrocarbon radical or an alkyl group or an alkenyl or alkynyl group which may contain 1 to 20 C atoms and in which individual H atoms or CH2 groups may be substituted by the above-mentioned groups, preferably the radicals methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl, neo-pentyl, cyclopentyl, n-hexyl, neo-hexyl, cyclohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, ethenyl, propenyl, butenyl, pentenyl, Cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, ethynyl, propynyl, butynyl, pentinyl, hexynyl, heptynyl or octynyl.Unter einer Alkoxygruppe mit 1 bis 40 C-Atomen werden bevor- zugt Methoxy, Trifluormethoxy, Ethoxy, n-Propoxy, i-Propoxy, n-Butoxy, i-Butoxy, s-Butoxy, t-Butoxy, n-Pentoxy, s-Pentoxy, 2-Methylbutoxy, n- Hexoxy, Cyclohexyloxy, n-Heptoxy, Cycloheptyloxy, n-Octyloxy, Cyclo- octyloxy, 2-Ethylhexyloxy, Pentafluorethoxy und 2,2,2-Trifluorethoxy ver- standen. Unter einer Thioalkylgruppe mit 1 bis 40 C-Atomen werden ins- besondere Methylthio, Ethylthio, n-Propylthio, i-Propylthio, n-Butylthio,.

[0032] 1-Butylthio, s-Butylthio, t-Butylthio, n-Pentylthio, s-Pentylthio, n-Hexylthio, Cyclohexylthio, n-Heptylthio, Cycloheptylthio, n-Octylthio, Cyclooctylthio,

[0033] 2-Ethylhexylthio, trifluoromethylthio, pentafluoroethylthio, 2,2,2-trifluoroethylthio, ethenylthio, propenylthio, butenylthio, pentenylthio, cyclopentenylthio, hexenylthio, cyclohexenylthio, heptenylthio, cycloheptenylthio, octenylthio, cyclooctenylthio, ethynylthio, propynylthio, butynylthio, pentynylthio, hexynylthio, heptynylthio, or octynylthio. In general, alkyl, alkoxy, or thioalkyl groups according to the present invention can be straight-chain, branched, or cyclic, where one or more non-adjacent CH2 groups can be replaced by the above-mentioned groups; Furthermore, one or more H atoms can be replaced by D, F, Cl, Br, I, CN or NO2, preferably F, Cl or CN, more preferably F or CN, particularly preferably CN.

[0034] An aromatic or heteroaromatic ring system with 5 - 60 or 5 to 40 aromatic ring atoms, which may also be substituted with the above-mentioned radicals and which may be linked to the aromatic or heteroaromatic ring via any position, is understood to mean, in particular, groups derived from benzene, naphthalene, anthracene, benzanthracene, phenanthrene, pyrene, chrysene, perylene, fluoranthene, naphthacene, pentacene, benzopyrene, biphenyl, biphenylene, terphenyl, triphenylene, fluorene, spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- or trans-indenofluorene, cis- or trans-indenocarbazole, cis- or trans-indolocarbazole, truxene, isotruxene, spirotruxene, spiroisotruxene, furan, benzofuran, iso- benzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, pyridine, quinoline, iso-quinoline, acridine, phenanthridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-chinolin, Phenothiazin, Phenoxazin, Pyrazol, Indazol, Imidazol, Benzimidazol, Naphthimidazol, Phenanthrimidazol, Pyridimidazol, Pyrazin- imidazol, Chinoxalinimidazol, Oxazol, Benzoxazol, Naphthoxazol, Anthroxazol, Phenanthroxazol, Isoxazol, 1 ,2-Thiazol, 1 ,3-Thiazol, Benzo- thiazol, Pyridazin, Hexaazatriphenylen, Benzopyridazin, Pyrimidin, Benz- pyrimidin, Chinoxalin, 1 ,5-Diazaanthracen, 2,7-Diazapyren, 2,3-Diaza- pyren, 1 ,6-Diazapyren, 1 ,8-Diazapyren, 4,5-Diazapyren, 4,5,9, 10-Tetra- azaperylen, Pyrazin, Phenazin, Phenoxazin, Phenothiazin, Fluorubin, Naphthyridin, Azacarbazol, Benzocarbolin, Phenanthrolin, 1 ,2,3-Triazol, 1 ,2,4-Triazol, Benzotriazol, 1 ,2,3-Oxadiazol, 1 ,2,4-Oxadiazol, 1 ,2,5-Oxa- diazol, 1 ,3,4-Oxadiazol, 1 ,2,3-Thiadiazol, 1 ,2,4-Thiadiazol, 1 ,2,5-Thiadi- azol, 1 ,3,4-Thiadiazol, 1 ,3,5-Triazin, 1 ,2,4-Triazin, 1 ,2,3-Triazin, Tetrazol, 1 ,2,4,5-Tetrazin, 1 ,2,3,4-Tetrazin, 1 ,2,3,5-Tetrazin, Purin, Pteridin, Indolizin und Benzothiadiazol oder Gruppen,which are derived from combinations of these systems.,

[0035] For the purposes of this description, the phrase "two or more residues can form a ring" is understood to mean, among other things, that the two residues are linked by a chemical bond with the formal elimination of two hydrogen atoms. This is illustrated by the following scheme.

[0036] Furthermore, the above formulation should also be understood to mean that if one of the two residues represents hydrogen, the second residue binds to the position to which the hydrogen atom was bonded, forming a ring. This is illustrated by the following scheme:

[0037] In a preferred embodiment, the compounds according to the invention can preferably comprise at least one structure of the formulas (I-1) to (I-6), and are particularly preferably selected from the compounds of the formulas (I-1) to (I-6),

[0038] where the symbols X, Z, R c and R d have the meanings given above, in particular for formula (I).

[0039] Structures / compounds of the formulas (I-1) to (I-4) are preferred and structures / compounds of the formulas (I-1) to (I-3) are particularly preferred and structures / compounds of the formula (I-1) are very particularly preferred.

[0040] Preferably, it can be provided that the radical R is selected, identically or differently, at each occurrence from H, D, C(Ar)s, C(R e )3, Si(Ar)s, Si(R e )3, Ge(Ar)3, Ge(R e)3, , a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 C atoms, wherein the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group is each substituted with one or more radicals R e may be substituted, wherein one or more non-adjacent CH2 groups are substituted by R e C=CR e , C=C, Si(R e )2, NR e , -O-, or -S-, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each of which is substituted by one or more radicals R e may be substituted, or an arylalkyl or heteroarylalkyl group having 5 to 60 aromatic ring atoms and 1 to 10 C atoms in the alkyl radical, which may be substituted by one or more radicals R emay be substituted; two radicals R may also be substituted with each other or at least one radical R may be substituted with another group, preferably R c or R d form a ring system.

[0041] Preferably, the radical Ar or at least one radical R represents an aromatic or heteroaromatic ring system having 5 to 18, preferably 5 to 13, particularly preferably 6 to 13 aromatic ring atoms, which is substituted by one or more radicals R e can be substituted.

[0042] Furthermore, it can be provided that the radical Ar is selected, identically or differently on each occurrence, from phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene, naphthalene, indole, benzofuran, benzothiophene, carbazole, dibenzofuran, dibenzothiophene, indenocarbazole, indolocarbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene or triphenylene, which are each substituted with one or more radicals R emay be substituted, preferably phenyl, biphenyl, fluorene, dibenzofuran, triphenylene, carbazole, indolocarbazole. In a preferred embodiment, it can be provided that at least one radical R is selected from phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene, naphthalene, indole, benzofuran, benzothiophene, carbazole, dibenzofuran, dibenzothiophene, indenocarbazole, indolocarbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene or triphenylene, which are each substituted with one or more radicals R e may be substituted, preferably phenyl, biphenyl, fluorene, dibenzofuran, triphenylene, carbazole, indolocarbazole.

[0043] The radical Ar or R can preferably represent a phenyl group which is substituted with at least one radical R eis substituted, wherein the substituent is in the ortho-, meta-, or para-position relative to the bonding site to the nitrogen atom. For example, in the case where the radical R e is a phenyl group, an ortho-, meta-, para-biphenyl group can be formed.

[0044] In the event that the radical Ar or R represents a triazine group, it can preferably be provided that the triazine group has two radicals R e which are not equal to H or D, where the two radicals R e preferably an aromatic or heteroaromatic ring system having 5 to 60, preferably 6 to 30 aromatic ring atoms, each represented by one or more radicals R 1 can be substituted.

[0045] Furthermore, the radical Ar or R can preferably represent a phenyl group which is reacted with at least one radical R eis substituted, wherein the substituent together with the phenyl group represented by the group Ar forms a fluorene residue which can be linked via the 1-, 2-, 3- or 4-position, a spirobifluorene residue which can be linked via the 1-, 2-, 3- or 4-position, an indole residue, a benzofuran residue, a benzothiophene residue, a carbazole residue which can be linked via the 1-, 2-, 3- or 4-position, a dibenzofuran residue which can be linked via the 1-, 2-, 3- or 4-position, a dibenzothiophene residue which can be linked via the 1-, 2-, 3- or 4-position, an indenocarbazole residue or an indolocarbazole residue. In a further embodiment, it can be provided that the structure / compound according to the present invention comprises at least one electron transport group, preferably a triazine group.Electron-transport groups are widely known in the art and enhance the ability of compounds to transport and / or conduct electrons. Examples of electron-transport groups include pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinazoline, quinoxaline, quinoline, isoquinoline, imidazole, and / or benzimidazole groups, with triazine groups being particularly preferred.

[0046] Furthermore, it can be provided that the structure / compound according to the present invention does not comprise a phosphine oxide residue, preferably an electron-withdrawing residue. Electron-withdrawing residues include, in particular, S(=O)2Ar', S(=O)2R e , B(R e ), B(Ar'), P(R e )O, P(Ar')O, which may be present, for example, as a substituent of the groups Ar or R. Furthermore, these electron-withdrawing residues may also be present as a substituent R a , R b , R c , R d , R ebe contained in the structure / compound according to formula (I) and / or formulas (I-1) to (I-6), for example as substituents B(Ar')2, B(R 1 )2, P(=O)(Ar')2, P(=O)(R 1 )2, S(=O)2Ar', S(=O)2R 1 . Furthermore, electron-withdrawing residues also include, for example, C=O groups or CN residues, which can be included as substituents in the structures, for example as substituents C(=O)Ar, C(=O)Ar', C(=O)R e , C(=O)R e or C(=O)R 1 .

[0047] In a further embodiment, the structure / compound according to the present invention may contain at least one hole-transport group. Hole-transport groups are also known in the art, and these preferably comprise triarylamine or carbazole groups.

[0048] The present compounds are particularly suitable as host material for emitters, preferably as host material for singlet, triplet, and TADF emitters, electron-transport material, electron-injection material, hole-conductor material, hole-injection material, electron-blocking material, and hole-blocking material in an electronic device. The specific properties of the compounds depend on the type and number of the respective functional groups. Compounds that comprise one, two, or more electron-transport groups, but no hole-transport group, are particularly suitable as host material. Compounds that comprise one, two, or more hole-transport groups, but no electron-transport group, are particularly suitable as host material, hole-conductor material, hole-injection material, and / or electron-blocking material.Compounds comprising one, two or more hole transport groups and one, two or more electron transport groups and / or electron withdrawing residues are preferably suitable as host material.

[0049] Furthermore, it can be provided that at least one of the radicals R, R c , R d , R e is / are not equal to H, preferably not equal to H, D, OH, NO2, F, CI, Br, I. Furthermore, it can be provided that none of the radicals R, R a , R b , R c , R d , R e equals OH, NO2, F, CI, Br, I.

[0050] In a further preferred embodiment, it can be provided that the compounds according to the invention have a structure of the formulas (II-1) to

[0051] (II-26), wherein the compounds according to the invention can particularly preferably be selected from the compounds of the formulas (II-1) to (II-26),

[0052] where the symbols Z, R c and R d have the meanings given above, in particular for formula (I) and the following applies to the other symbols:

[0053] Y e represents, the same or different at each occurrence, C(R e )2, Si(R e )2, Ge(R e )2, C=O, C=NR e , C=C(R e )2, 0, S, S=0, SO2, N(R e ), P(R e ) or P(=O)R e , preferably for N(R e ), 0, S, C(R e )2 or Si(R e )2, particularly preferably for N(R e ), 0 or S, where R e has the meaning given in claim 1, or in the case that a group binds to the structure, represents N-, C(R e )-, Si(R e )- or Ge(R e )-;

[0054] X e stands for N, CR, the same or different at each occurrence eor C, in case a group binds to the structure, preferably for CR e or C, provided that no more than three of the groups X e in a cycle for N, where R e has the meaning given in claim 1; n is 0, 1, 2 or 3, preferably 0, 1 or 2, m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2.

[0055] Structures / compounds of the formulas (II-1) to (II-5), (II-9), (II-11), (II-12), (II-16), (II-19) and (II-23) are preferred and structures / compounds of the formulas (II-1), (II-5), (II-9), (II-12) and (II-16) are particularly preferred.

[0056] In formulas (11-1 ) to (II-26) it can be provided that X e represents C if a group binds to the respective structure. This group is in particular the one shown in formulas (II-5) to (II-8) and formulas (II-12) to (II-18), with a radical Y eThis ring structure can be linked here via a residue X e or via Y e bind, where in the latter case Y e for N-, C(R e )-, Si(R e )- or Ge(R e )- stands.

[0057] In one embodiment, it can be provided that in structures / compounds of the formulas (II-1) to (II-26) at most three, preferably two groups X e per ring for N, preferably all X e for CR e preferably at least one, particularly preferably at least two of the groups X e per ring are selected from CH and CD.

[0058] Furthermore, it can be provided that at least one, preferably at least two and particularly preferably three groups X eper ring represents N, whereby these groups are preferably not adjacent. These structures / compounds preferably comprise electron-transport groups and are therefore particularly suitable as matrix materials.

[0059] In a further preferred embodiment, it can be provided that the compounds according to the invention comprise a structure of the formulas (III-1) to (III-34), wherein the compounds according to the invention can particularly preferably be selected from the compounds of the formulas (III-1) to (III-34),

[0060] where the symbols Z, R c , R d and R e have the meanings given above, in particular for formula (I) and the following applies to the other symbols:

[0061] Y e represents, the same or different at each occurrence, C(R e )2, Si(R e )2, Ge(R e )2, C=O, C=NR e , C=C(Re )2, 0, S, S=0, SO2, N(R e ), P(R e ) or P(=O)R e , preferably for N(R e ), 0, S, C(R e )2 or Si(R e )2, particularly preferably for N(R e ), 0 or S, where R e has the meaning given in claim 1, or in the case that a group binds to the structure, represents N-, C(R e )-, Si(R e )- or Ge(R e)-; j is 0, 1 or 2; n is 0, 1, 2 or 3, preferably 0, 1 or 2; m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2; l is 0, 1, 2, 3, 4 or 5, preferably 0, 1 or 2. Structures / compounds of the formulas (III-1) to (III-5), (III-9), (III-11), (III-12), (III-16), (III-19) and (III-23) are preferred and structures / compounds of the formulas (III-1) to (III-5), (III-9), (III-11), (III-12), (III-16) and (III-19) are particularly preferred and structures / compounds of the formulas (III-9), (III-12) and (III-19) are very particularly preferred. The sum of the indices j, m, n and l in structures / compounds of the formulas (III-1) to (III-34) is preferably at most 6, particularly preferably at most 4 and particularly preferably at most 2.Furthermore, in a particularly preferred embodiment, it can be provided that the compounds according to the invention comprise a structure of the formulas (IV-1) to (IV-48), wherein the compounds according to the invention can particularly preferably be selected from the compounds of the formulas (IV-1) to (IV-48).

[0062] where the symbols Z, R c , R d and R e have the meanings given above, in particular for formula (I) and the following applies to the other symbols: Y e represents, the same or different at each occurrence, C(R e )2, Si(R e )2, Ge(R e )2, C=O, C=NR e , C=C(R e )2, O, S, S=O, SO2, N(R e ), P(R e ) or P(=O)R e , preferably for N(R e ), O, S, C(R e )2 or Si(R e )2, particularly preferably for N(R e), O or S; n is 0, 1, 2 or 3, preferably 0, 1 or 2; m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2; l is 0, 1, 2, 3, 4 or 5, preferably 0, 1 or 2. Structures / compounds of the formulas (IV-1) to (IV-8), (IV-17) to (IV-24) and (IV-33) to (IV-40) are preferred, structures / compounds of the formulas (IV-1), (IV-4), (IV-5), (IV-8), (IV-17), (IV-20), (IV-21), (IV-24), (IV-33), (IV-36), (IV-37) and (IV-40) are particularly preferred and structures / compounds of the formulas IV-1), (IV-5), (IV-17), (IV-21), (IV-33) and (IV-37) are very particularly preferred.

[0063] The sum of the indices m, n and I in structures / compounds of the formulas (IV-1) to (IV-48) is preferably at most 6, particularly preferably at most 4 and particularly preferably at most 2.

[0064] When two residues, which can be selected in particular from R, R e , R 1 and / or R 2, form a ring system, this can be mono- or polycyclic, aliphatic, heteroaliphatic, aromatic or heteroaromatic. In the case that residues with a group R a , R b , R c and / or R d form a ring system, this can be mono- or polycyclic, aliphatic or heteroaliphatic. Two radicals R c and / or R d represent an aromatic or heteroaromatic ring system which is linked, for example two residues R c and / or R d a fluorene group or a phenanthrenyl group, etc. The residues that form a ring system with each other can be adjacent, ie these residues are bonded to the same carbon atom or to carbon atoms that are directly bonded to each other, or they can be further apart.

[0065] In a preferred development of the present invention, it can be provided that at least two, preferably adjacent, radicals R c , R d , R e with the other groups to which the two residues R c , R d , R ebind, form a condensed ring. In a preferred embodiment, it can be provided that ring structures are formed which are described in the document WO 2022 / 079068 A1, filed on October 13, 2021 with the European Patent Office under application number PCT7EP2021 / 078240, wherein for disclosure purposes the description of the condensed ring structures set out in these documents, which are described by the ring elements of the formulas (RA-1) to (RA-12), (RA-1 a) to (RA-4f) and / or (RB) on pages 37 to 40 of the document WO 2022 / 079068 A1, is incorporated into the present application by reference hereto. The ring structures set out above and detailed in the document WO 2022 / 079068 A1, which preferably comprise the ring elements of the formulae (RA-1) to (RA-12) and (RA-1 a) to (RA-4f), lead in particular to structures / compounds according to the invention which have a surprisingly low refractive index.

[0066] Furthermore, it can be provided that the substituents R, R a , R b , R c , R d , R e , R 1 and R 2 according to the above formulas with the ring atoms of the ring system to which the substituents R, R a , R b , R c , R d , R e , R 1 and R 2 bind, do not form a fused aromatic or heteroaromatic ring system, particularly preferably no ring system. This includes the formation of a fused aromatic or heteroaromatic ring system with possible substituents R 2 which are attached to the substituents R a , R b , R c , R d , R e and R 1 may be bound.

[0067] Furthermore, it can be provided that at least one radical R a , R b , R c , R d , R eis selected, identically or differently on each occurrence, from the group consisting of H, D, a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 C atoms or an aromatic or heteroaromatic ring system selected from the groups of the following formulas Ar-1 to Ar-76, preferably the radical R e is selected, identically or differently on each occurrence, from the group consisting of H, D or an aromatic or heteroaromatic ring system selected from the groups of the following formulas Ar-1 to Ar-76, and / or the group Ar' is selected, identically or differently on each occurrence, from the groups of the following formulas Ar-1 to Ar-76,

[0068] where R 1 has the meanings given above, the dashed bond represents the bond to the corresponding group and furthermore:

[0069] Ar 1 is at each occurrence, identically or differently, a bivalent aromatic or heteroaromatic ring system having 6 to 18 aromatic ring atoms, each of which is substituted by one or more radicals R 1 can be substituted;

[0070] A is the same or different at each occurrence C(R 1 )2, NR 1 , 0 or S; p is 0 or 1 , where p = 0 means that the group Ar 1 is not present and that the corresponding aromatic or heteroaromatic group is directly bonded to the corresponding residue; q is 0 or 1, where q = 0 means that no group A is bonded to this position and that the corresponding carbon atoms are bonded instead to residues R 1 are bound.

[0071] Structures of the formulas (Ar-1), (Ar-2), (Ar-3), (Ar-12), (Ar-13), (Ar-14), (Ar-15), (Ar-16), (Ar-40), (Ar-41), (Ar-42), (Ar-43), (Ar-44), (Ar-45), (Ar-46), (Ar-69), (Ar-70), (Ar-76) are preferred and structures of the formulas (Ar-1), (Ar-2), (Ar-3), (Ar-12), (Ar-13), (Ar-14), (Ar-15), (Ar-16) are particularly preferred.

[0072] If the above-mentioned groups for structures of the formulas (Ar-1) to (Ar-76) have several groups A, all combinations from the definition of A are possible. Preferred embodiments are then those in which a group A represents NR 1 and the other group A for C(R 1 )2 or in which both groups A for NR 1 or in which both groups A stand for 0.

[0073] If A for NR 1 the substituent R 1which is bonded to the nitrogen atom, preferably represents an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms, which can also be substituted by one or more radicals R 2 In a particularly preferred embodiment, this substituent R 1 identical or different on each occurrence for an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, in particular having 6 to 18 aromatic ring atoms, which has no condensed aryl groups and which has no condensed heteroaryl groups in which two or more aromatic or heteroaromatic 6-ring groups are directly fused to one another, and which in each case also by one or more radicals R 2may be substituted. Phenyl, biphenyl, terphenyl and quaterphenyl are preferred. Triazine, pyrimidine and quinazoline are also preferred, as listed above for Ar-47 to Ar-50, Ar-57 and Ar-58, where these structures are substituted by R 1 by one or more residues R 2 can be substituted.

[0074] If A for C(R 1 )2, the substituents R 1 which are bonded to this carbon atom, preferably identically or differently on each occurrence, represent a linear alkyl group having 1 to 10 C atoms or a branched or cyclic alkyl group having 3 to 10 C atoms or an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms, which can also be substituted by one or more radicals R 2 R is particularly preferably 1 represents a methyl group or a phenyl group. The radicals R 1also form a ring system with each other, which leads to a spiro system.

[0075] In a preferred embodiment, the group Z can be used for C(R a ) and the group R a is selected from H, D, a straight-chain alkyl group having 1 to 10 C atoms, a branched or cyclic alkyl group having 3 to 15 C atoms, wherein the alkyl groups are each substituted by one or more radicals R 1 may be substituted or an aromatic or heteroaromatic ring system with 5 to 20 aromatic ring atoms, each substituted by one or more radicals R 1 may be substituted, preferably H, D, a straight-chain alkyl group having 1 to 10 C atoms, a branched or cyclic alkyl group having 3 to 15 C atoms or a phenyl group, each substituted by one or more radicals R 1 can be substituted, preferably deuterated.

[0076] Furthermore, it can be provided that the group Z represents Si(R b ) or Ge(R b ), preferably for Si(R b ) and the group R b is selected from a straight-chain alkyl group having 1 to 10 C atoms, a branched or cyclic alkyl group having 3 to 15 C atoms, wherein the alkyl groups are each substituted by one or more radicals R 1 may be substituted or an aromatic or heteroaromatic ring system with 5 to 20 aromatic ring atoms, each substituted by one or more radicals R 1 may be substituted, preferably a straight-chain alkyl group having 1 to 10 C atoms, a branched or cyclic alkyl group having 3 to 15 C atoms or a phenyl group, each substituted by one or more radicals R 1 can be substituted, preferably deuterated.

[0077] In the following, preferred residues R c and R dPreferably, the groups R bonded to a C atom c are equal.

[0078] Furthermore, it can be provided that the groups R bonded to different C atoms c are equal.

[0079] Furthermore, it can preferably be provided that the groups R bonded to a C atom d are equal.

[0080] Furthermore, it can be provided that the groups R bonded to different C atoms d are equal.

[0081] In addition, it can be provided that the groups R bonded to different C atoms c or R d are different.

[0082] In a preferred embodiment, it can be provided that the groups R c , R d stand for H or D.

[0083] Furthermore, it can be provided that the groups R bonded to a C atom c or the groups R bonded to a C atomd are selected from straight-chain alkyl groups having 1 to 10 C atoms or branched or cyclic alkyl groups having 3 to 10 C atoms, each of which is substituted by one or more radicals R 1 may be substituted, preferably deuterated, two or more, preferably adjacent, substituents R c , R d form a ring system with each other.

[0084] In addition, it can be provided that the groups R bonded to a C atom c , R d are selected from aromatic or heteroaromatic ring systems having 5 to 20 aromatic ring atoms, each of which is substituted by one or more radicals R 1 may be substituted, preferably phenyl groups, each of which is substituted by one or more radicals R 1 may be substituted, preferably deuterated, two or more, preferably adjacent, substituents R c , R dform a ring system with each other. In a preferred embodiment of the invention, R c and R d identically or differently on each occurrence selected from the group consisting of H, D, a straight-chain alkyl group having 1 to 20 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, where the alkyl group is in each case substituted with one or more radicals R 1 may be substituted, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, preferably with 5 to 40 aromatic ring atoms, each substituted by one or more radicals R 1 can be substituted.

[0085] Furthermore, it can be provided that at least one radical R c and / or R d , preferably a substituent R c and / or R dis selected, identically or differently at each occurrence, from the group consisting of H, D, an aromatic or heteroaromatic ring system having 6 to 30 aromatic ring atoms, which is reacted with one or more radicals R 1 may be substituted, or a group N(Ar')2, particularly preferably at least one substituent R c and / or R d is selected, identically or differently on each occurrence, from the group consisting of an aromatic or heteroaromatic ring system having 6 to 30 aromatic ring atoms, which is substituted with one or more radicals R 1 In a further preferred embodiment of the invention, the substituents R c and / or R d either a condensed ring or the residue R c and / or R dis selected, identically or differently at each occurrence, from the group consisting of H, D, an aromatic or heteroaromatic ring system having 6 to 30 aromatic ring atoms, which is reacted with one or more radicals R 1 may be substituted, or a group N(Ar')2. Particularly preferred is the radical R c and / or R d , preferably the substituent R c and / or R d identically or differently on each occurrence selected from the group consisting of H, D or an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, preferably having 6 to 18 aromatic ring atoms, particularly preferably having 6 to 13 aromatic ring atoms, each of which is substituted with one or more radicals R 1 can be substituted.

[0086] In the following, preferred residues R e In a preferred embodiment of the invention, R eidentically or differently at each occurrence selected from the group consisting of H, D, F, CN, Si(R 1 )s, Ge(R 1 )s, a straight-chain alkyl group having 1 to 20 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, wherein the alkyl group is in each case substituted with one or more radicals R 1 may be substituted, or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, preferably having 5 to 40 aromatic ring atoms, each substituted by one or more radicals R 1 can be substituted.

[0087] In a further preferred embodiment of the invention, radical R e identically or differently on each occurrence selected from the group consisting of H, D, F, a straight-chain alkyl group having 1 to 20 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, where the alkyl group is in each case substituted with one or more radicals R 1may be substituted, or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, preferably having 5 to 40 aromatic ring atoms, each substituted by one or more radicals R 1 can be substituted.

[0088] Furthermore, it can be provided that at least one radical R e , preferably a substituent R e is selected, identically or differently at each occurrence, from the group consisting of H, D, an aromatic or heteroaromatic ring system having 6 to 30 aromatic ring atoms, which is reacted with one or more radicals R 1 may be substituted, or a group N(Ar')2, particularly preferably at least one substituent R e is selected, identically or differently on each occurrence, from the group consisting of an aromatic or heteroaromatic ring system having 6 to 30 aromatic ring atoms, which is substituted with one or more radicals R 1In a further preferred embodiment of the invention, the substituents R e either a condensed ring or the residue R e is selected, identically or differently at each occurrence, from the group consisting of H, D, an aromatic or heteroaromatic ring system having 6 to 30 aromatic ring atoms, which is reacted with one or more radicals R 1 may be substituted, or a group N(Ar')2. Particularly preferred is the radical R e , preferably the substituent R e identically or differently on each occurrence selected from the group consisting of H or an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, preferably having 6 to 18 aromatic ring atoms, particularly preferably having 6 to 13 aromatic ring atoms, each of which is substituted with one or more radicals R 1 can be substituted.

[0089] Furthermore, it can be provided that at least one radical R c , R d and / or R e , preferably at least one radical R e , represents an aromatic or heteroaromatic ring system with 5 to 13 aromatic ring atoms, which is substituted with one or more radicals R 1 can be substituted.

[0090] Preferably, it can be provided that at least one radical, preferably a substituent R c , R d and / or R e , particularly preferably at least one radical R e , is selected from phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene, naphthalene, indole, benzofuran, benzothiophene, carbazole, dibenzofuran, dibenzothiophene, indenocarbazole, indolocarbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene or triphenylene, each of which is substituted with one or more radicals R 1may be substituted. The term substituent means in particular that R c , R d and / or R e are not equal to H, preferably not equal to H and not equal to D. Furthermore, the substituents R c , R d and / or R e be the same or different if two or more substituents are present which are selected from the aromatic or heteroaromatic group mentioned.

[0091] Preferred aromatic or heteroaromatic ring systems for which the radicals R, R a , R b , R c , R d and R eor Ar or Ar' are selected from phenyl, biphenyl, in particular ortho-, meta- or para-biphenyl, terphenyl, in particular ortho-, meta-, para- or branched terphenyl, quaterphenyl, in particular ortho-, meta-, para- or branched quaterphenyl, fluorene, which may be linked via the 1-, 2-, 3- or 4-position, spirobifluorene, which may be linked via the 1-, 2-, 3- or 4-position, naphthalene, in particular 1- or -linked naphthalene, indole, benzofuran, benzothiophene, carbazole, which may be linked via the 1-, 2-, 3- or 4-position, dibenzofuran, which may be linked via the 1-, 2-, 3- or 4-position, dibenzothiophene, which may be linked via the 1-, 2-, 3- or 4-position, Indenocarbazole, indolocarbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene or triphenylene, each of which is substituted with one or more radicals R e , R 1or R 2 Particularly preferred aromatic or heteroaromatic ring systems for which the radicals R, R a , R b , R c , R d and R e or Ar or Ar' are the structures (Ar-1) to (Ar-76) listed above, with structures of the formulas (Ar-1), (Ar-2), (Ar-3), (Ar-12), (Ar-13), (Ar-14), (Ar-15), (Ar-16), (Ar-69), (Ar-70), (Ar-76) being preferred and structures of the formulas (Ar-1), (Ar-2), (Ar-3), (Ar-12), (Ar-13), (Ar-14), (Ar-15), (Ar-16) being particularly preferred. With regard to the structures (Ar-1) to (Ar-76), it should be noted that these can be substituted with a possible R 1 In the case of the ring systems Ar or R, these possible substituents are R 1 by R e to replace.

[0092] Other suitable groups R, R a , R b , R c , R d and R eare groups of the formula -Ar 4 -N(Ar 2 )(Ar 3 ), where Ar 2 , Ar 3 and Ar 4 identically or differently on each occurrence represent an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms, each of which is substituted by one or more radicals R 1 The total number of aromatic ring atoms of Ar 2 , Ar 3 and Ar 4 maximum 60 and preferably maximum 40.

[0093] Ar 4 and Ar 2 with each other and / or Ar 2 and Ar 3 with each other also by a single bond or a group selected from C(R 1 )2, NR 1 , O or S. Preferably, the linking of Ar 4 and Ar 2 with each other or from Ar 2 and Ar 3are ortho to the position of the linkage to the nitrogen atom. In a further embodiment of the invention, none of the groups Ar 2 , Ar 3 or Ar 4 connected to each other. Ar is preferred 4 an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, preferably having 6 to 12 aromatic ring atoms, each of which is substituted by one or more radicals R 1 may be substituted. Particularly preferred is Ar 4 selected from the group consisting of ortho-, meta- or para-phenylene or ortho-, meta- or para-biphenyl, each of which is substituted by one or more radicals R 1 may be substituted, but are preferably unsubstituted. Ar is particularly preferred 4 an unsubstituted phenylene group.

[0094] Preference is given to Ar 2 and Ar 3identically or differently on each occurrence, an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, each substituted by one or more radicals R 1 Particularly preferred groups Ar 2 or Ar 3 are, identically or differently at each occurrence, selected from the group consisting of benzene, ortho-, meta- or para-biphenyl, ortho-, meta-, para- or branched terphenyl, ortho-, meta-, para- or branched quaterphenyl, 1-, 2-, 3- or 4-fluorenyl, 1-, 2-, 3- or 4-spiro-bifluorenyl, 1- or 2-naphthyl, indole, benzofuran, benzothiophene, 1-, 2-

[0095] 3- or 4-carbazole, 1-, 2-, 3- or 4-dibenzofuran, 1-, 2-, 3- or 4-di-benzothiophene, indenocarbazole, indolocarbazole, 2-, 3- or 4-pyridine, 2-,

[0096] 4- or 5-pyrimidine, pyrazine, pyridazine, triazine, phenanthrene or triphenylene, each of which is substituted with one or more radicals R 1may be substituted. Particularly preferred are Ar 2 and Ar 3 identically or differently on each occurrence selected from the group consisting of benzene, biphenyl, in particular ortho-, meta- or para-biphenyl, terphenyl, in particular ortho-, meta-, para- or branched terphenyl, quaterphenyl, in particular ortho-, meta-, para- or branched quaterphenyl, fluorene, in particular 1-, 2-, 3- or 4-fluorene, or spirobifluorene, in particular 1-, 2-, 3- or 4-spirobifluorene.

[0097] With the limitations set out in claim 1, the conditions for the radicals R e preferences also the residues R a , R b , R c and R d .

[0098] In a further preferred embodiment of the invention, R 1identically or differently on each occurrence selected from the group consisting of H, D, F, CN, a straight-chain alkyl group having 1 to 10 C atoms or a branched or cyclic alkyl group having 3 to 10 C atoms, where the alkyl group is in each case substituted with one or more radicals R 2 may be substituted, or an aromatic or heteroaromatic ring system with 6 to 24 aromatic ring atoms, each substituted by one or more radicals R 2 may be substituted. In a particularly preferred embodiment of the invention, R 1 identically or differently on each occurrence selected from the group consisting of H, a straight-chain alkyl group having 1 to 6 C atoms, in particular having 1, 2, 3 or 4 C atoms, or a branched or cyclic alkyl group having 3 to 6 C atoms, where the alkyl group is substituted with one or more radicals R 2may be substituted, but is preferably unsubstituted, or an aromatic or heteroaromatic ring system having 6 to 13 aromatic ring atoms, each substituted by one or more radicals R 2 can be substituted, but is preferably unsubstituted.

[0099] In a further preferred embodiment of the invention, R 2 identical or different on each occurrence H, an alkyl group having 1 to 4 C atoms or an aryl group having 6 to 10 C atoms, which may be substituted by an alkyl group having 1 to 4 C atoms, but is preferably unsubstituted.

[0100] In compounds according to the invention that are processed by vacuum evaporation, the alkyl groups preferably have no more than five carbon atoms, particularly preferably no more than 4 carbon atoms, and most preferably no more than 1 carbon atom. Also suitable for compounds that are processed from solution are compounds that are substituted by alkyl groups, particularly branched alkyl groups, with up to 10 carbon atoms, or that are substituted by oligoarylene groups, for example ortho-, meta-, para-, or branched terphenyl or quaterphenyl groups.

[0101] In a preferred embodiment, the structures / compounds according to the invention have a high degree of deuteration. It can preferably be provided that the degree of deuteration is at least 50%, preferably at least 80%, especially preferably at least 90%, and most preferably at least 95%. The degree of deuteration is determined from the numerical ratio of deuterium to the sum of deuterium and 1 H-hydrogen (D / (D+H)*100). The compounds are particularly preferably fully deuterated.

[0102] The compounds of the invention are particularly suitable for use in blue-emitting electroluminescent devices. Depending on the layer, these require materials with a high triplet level. However, many substituents with fused aromatic or heteroaromatic groups can lead to a reduction in the triplet level.

[0103] Accordingly, naphthyl structures are preferred over anthracene structures. Furthermore, fluorenyl, spirobifluorenyl, dibenzofuranyl, and / or dibenzothienyl structures are preferred over naphthyl structures.

[0104] Particularly preferred are structures which do not exhibit condensation, such as phenyl, biphenyl, terphenyl and / or quaterphenyl structures.

[0105] Particularly preferably, it can further be provided that the radical Ar or R does not comprise an anthracene group, preferably none of the radicals Ar, R, R a , R b , R c , R d , R e an anthracene group.

[0106] It can also be provided, very particularly preferably, that the radical Ar or R does not comprise an aromatic or heteroaromatic ring system which has three linearly condensed aromatic 6 rings, wherein preferably none of the radicals Ar, R, R a , R b , R c , R d, R e an aromatic or heteroaromatic ring system which has three linearly condensed aromatic 6 rings.

[0107] If the compound according to the invention is reacted with aromatic or heteroaromatic groups R a , R b , R c , R d , R e , R 1 or R 2is substituted, it is preferred if these do not contain any aryl or heteroaryl groups with more than two directly fused aromatic six-membered rings. Particularly preferably, the substituents do not contain any aryl or heteroaryl groups with directly fused six-membered rings. This preference is due to the low triplet energy of such structures. Condensed aryl groups with more than two directly fused aromatic six-membered rings that are nevertheless also highly suitable for the invention are phenanthrene and triphenylene, since these also have a high triplet level.

[0108] Furthermore, it can be provided that none of the radicals Ar, R, R a , R b , R c , R d and R e , preferably none of the residues Ar, R, R a , R b , R c , R d , R e , R 1 and R 2comprises or forms a fluorenone group. This includes substituents attached to the radicals Ar, R, R a , R b , R c , R d , R e , etc. A fluorenone comprises a 5-membered ring with a CO group to which two aromatic 6-membered rings are fused.

[0109] When the compounds of formula (I) or the preferred embodiments are used as matrix material for a phosphorescent emitter or in a layer directly adjacent to a phosphorescent layer, it is further preferred if the compound does not contain any condensed aryl or heteroaryl groups in which more than two six-membered rings are directly condensed to one another. Exceptions to this are phenanthrene and triphenylene, which may be preferred due to their high triplet energy despite the presence of condensed aromatic six-membered rings.

[0110] Preferably, it can be provided that the compound according to the invention has an energy of the lowest triplet state Ti of at least 2.7 eV, preferably at least 2.9 eV, particularly preferably at least 3.1 eV.

[0111] Molecular orbitals, in particular the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), their energy levels, and the energy of the lowest triplet state Ti or the lowest excited singlet state Si of the materials are determined using quantum chemical calculations. To calculate organic substances, a geometry optimization is first performed using the "Ground State / Semi-empirical / Default Spin / AM1 / Charge O / Spin Singlet" method. Subsequently, an energy calculation is performed based on the optimized geometry. The "TD-SCF / DFT / Default Spin / B3PW91" method is used with the "6-31 G(d)" basis set (Charge 0, Spin Singlet). The energy calculation yields the HOMO energy level HEh or LUMO energy level LEh in Hartree units. From this, the HOMO and LUMO energy levels calibrated using cyclic voltammetry measurements are determined in electronvolts as follows:

[0112] HOMO(eV) = ((HEh*27.212)-0.9899) / 1 .1206

[0113] LUMO(eV) = ((LEh*27.212)-2.0041 ) / 1.385

[0114] For the purposes of this application, these values ​​are to be regarded as HOMO or LUMO energy levels of the materials.

[0115] The lowest triplet state Ti is defined as the energy of the triplet state with the lowest energy resulting from the described quantum chemical calculation.

[0116] The lowest excited singlet state Si is defined as the energy of the excited singlet state with the lowest energy resulting from the described quantum chemical calculation.

[0117] The method described here is independent of the software package used and always produces the same results. Examples of commonly used programs for this purpose are "GaussianO9W" (Gaussian Inc.) and Q-Chem 4.1 (Q-Chem, Inc.).

[0118] Furthermore, it can be provided that the compound comprises exactly two or exactly three structures according to formula (I), (I-1) to (I-6), (II-1) to (II-26), (III-1) to (III-34) and / or (IV-1) to (IV-48).

[0119] In a preferred embodiment, the compounds are selected from compounds of formula (D-1),

[0120] where group L 1 represents a linking group, preferably a bond or an aromatic or heteroaromatic ring system having 5 to 40, preferably 5 to 30 aromatic ring atoms, which is substituted by one or more radicals R e may be substituted, and the further symbols and indices used have the meanings given in claim 1, wherein the group L 1 forms a bond to the basic structure instead of a hydrogen atom or a substituent, preferably the group L 1 binds to the residues X.

[0121] In a further preferred embodiment of the invention, L 1 for a bond or for an aromatic or heteroaromatic ring system having 5 to 14 aromatic or heteroaromatic ring atoms, preferably an aromatic ring system having 6 to 12 carbon atoms, which is substituted by one or more radicals R e may be substituted, but is preferably unsubstituted, where R e may have the meaning given above, in particular for formula (I). L is particularly preferably 1 represents an aromatic ring system with 6 to 10 aromatic ring atoms or a heteroaromatic ring system with 6 to 13 heteroaromatic ring atoms, each represented by one or more radicals R 1 may be substituted, but is preferably unsubstituted, where R 1 which may have the meaning given above, in particular for formula (I).

[0122] Furthermore, the symbol L shown inter alia in formula (D1 ) is preferably 1 identical or different on each occurrence for a bond or an aryl or heteroaryl radical having 5 to 24 ring atoms, preferably 6 to 13 ring atoms, particularly preferably 6 to 10 ring atoms, so that an aromatic or heteroaromatic group of an aromatic or heteroaromatic ring system is bonded directly, ie via an atom of the aromatic or heteroaromatic group, to the respective atom of the further group.

[0123] Furthermore, it can be provided that the group L shown in formula (D1 ) 1 an aromatic ring system with at most four, preferably at most three, particularly preferably at most two fused aromatic and / or heteroaromatic 6-membered rings, preferably no fused aromatic or heteroaromatic ring system.

[0124] Examples of suitable aromatic or heteroaromatic ring systems L 1 are selected from the group consisting of ortho-, meta- or para-phenylene, ortho-, meta- or para-biphenylene, terphenylene, in particular branched terphenylene, quaterphenylene, in particular branched quaterphenylene, fluorenylene, spirobifluorenylene, dibenzofuranylene, dibenzothienylene and carbazolylene, each of which is substituted by one or more radicals R 1 may be substituted, but are preferably unsubstituted.

[0125] According to a preferred embodiment, a compound according to the invention can be prepared by at least one of the structures according to formulas (I), (I-1) to (I-6), (II-1) to (II-26), (III-1) to (III-34) and / or (IV-1) to (IV-48). Compounds according to the invention, preferably comprising structures according to formulas (I), (I-1) to (I-6), (II-1) to (II-26), (III-1) to (III-34) and / or (IV-1) to (IV-48), preferably have a molecular weight of less than or equal to 5000 g / mol, preferably less than or equal to 4000 g / mol, particularly preferably less than or equal to 3000 g / mol, especially preferably less than or equal to 2000 g / mol, more especially preferably less than or equal to 1200 g / mol and very particularly preferably less than or equal to 900 g / mol.

[0126] Furthermore, preferred compounds according to the invention are characterized by the fact that they are sublimable. These compounds generally have a molecular weight of less than approximately 1200 g / mol. Furthermore, it can be provided that the compound comprising structures according to formula (I), preferably the compound according to formula (I) or a preferred embodiment of this structure / compound, is not in direct contact with a metal atom, preferably does not represent a ligand for a metal complex. The above-mentioned preferred embodiments can be combined with one another as desired within the restrictions defined in claim 1. In a particularly preferred embodiment of the invention, the above-mentioned preferences occur simultaneously. Examples of preferred compounds according to the above-mentioned embodiments are the compounds listed in the following table.

[0127]

[0128]

[0129] The basic structure of the compounds of the invention can be prepared according to the methods outlined in the schemes below. The individual synthesis steps, such as coupling reactions leading to C–C and / or C–N bond formations, are known in principle to those skilled in the art. These include, among others, reactions according to BUCHWALD, SUZUKI, YAMAMOTO, STILLE, HECK, NEGISHI, SONOGASHIRA, and HIYAMA. Further information on the synthesis of the compounds of the invention can be found in the synthesis examples.

[0130] For example, the preparation of compounds according to the invention, in particular of unsubstituted and aliphatically or aromatically substituted 10a, 11-dihydro-10H-indolo[1,2-a]indoles, can be carried out in accordance with processes described in detail in the literature (see, for example, ES Sherman et al., Adv. Synth. Catal. 2009, 351, 467 and W. Du et al., J. Am. Chem. Soc. 2015, 137, 1130), whereby the processes can be carried out by using correspondingly aliphatically substituted with R a , R c and / or R d or aromatically substituted with R 2-(2-propen-1-yl)-N-phenylanilines to aliphatic with R a , R° and / or R dor aromatically substituted 10a, 11-dihydro-10H-indolo[1,2-a]indoles (see general Scheme 1a and 1b). The copper-catalyzed process of ES Sherman et al. is particularly suitable for the preparation of aromatic halogen-substituted derivatives with R = F, CI, Br, while the palladium-catalyzed process of W. Du et al. is suitable for the introduction of aliphatic or aromatic radicals R a = Me, Et, t-Bu, neo-pentyl, Ph, biphenyl, etc.

[0131] Scheme 1 a: ES Sherman et al., Adv. Synth. Catal. 2009, 351, 467

[0132] Scheme 1b: W. Du et al., J. Am. Chem. Soc.2015, 137, 1130 The 10a,11-dihydro-10H-indolo[1,2-a]indoles obtained by the above-mentioned processes can be further functionalized using common electrophilic aromatic substitution methods. Depending on the chosen stoichiometry, sequential mono-, di-, tri-, and tetra-halogenation is particularly successful, for example, preferably as bromination with N-bromosuccinimide (NBS) in dichloromethane, trifluoroethanol, THF, or DMF, first in the para and then in the ortho position to the nitrogen atom (Scheme 2). Scheme 2: 1eq 1eq NBS NBS

[0133] The resulting halogen compounds can be further functionalized by conventional methods such as CC coupling (Suzuki, Negishi, Sonogashira, Grignard-Cross, etc.) or CN coupling (Buchwald-Hartwig, Ullmann, etc.), as exemplified for the monobromide in Scheme 3. Di-, tri-, and tetrahalides can be reacted analogously. The group Ar / HetAr represents an aromatic or heteroaromatic ring system. C–N coupling of the Buchwald-Hartwig type: The groups Ar 1 / Ar 2represent an aromatic or heteroaromatic ring system. Reactive leaving groups or their precursors, e.g., methoxy groups, can be incorporated into the synthesis of 10a,11-dihydro-10H-indolo[1,2-a]indole. The regioisomer mixture obtained during the cyclization can be separated by conventional methods (chromatography, fractional crystallization) (see ES Sherman et al., Adv. Synth. Catal. 2009, 351, 467). The methoxy groups can then be saponified by conventional methods, e.g., in a pyridinium hydrochloride melt, and the resulting bisphenols can be esterified with trifluoromethanesulfonic anhydride. The triflate leaving group thus introduced can then be further functionalized by CC coupling (Suzuki, Negishi, Sonogashira, Grignard-Cross, etc.) or CN coupling (Buchwald-Hartwig, Ullmann, etc.). Scheme 4: ES Sherman et al., Adv. Synth. Catal. 2009, 351, 467 The functionalized 10a,11-dihydro-10H-indolo[1,2-a]indoles described above can be converted into fluorenes using methods known from the literature (L. Zhang et al., Organic Process Research & Development (2020), 24(10), 2078;

[0134] I. Abdellah et al..Catalysis Science & Technology (2018), 8(24), 6486;

[0135] Campeau et al., J. Am. Chem. Soc., 2006), dibenzofurans & dibenzothiophenes (Campeau et al., J. Am. Chem. Soc., 2006, 128, 593.) or carbazoles (Campeau et al., J. Am. Chem. Soc., 2006, 128, 593; K. Suzuki et al., Adv. Synth. & Catal., 2008, 350(5), 652, AW Freeman et al., J. Org. Chem. 2005, 70, 5014), whereby regioisomers of the cyclization can be separated chromatographically or by fractional crystallization, see Scheme 5.

[0136]

[0137] Further functionalization of the can be shown in Scheme 5

[0138] Compounds can be prepared using the methods shown in Schemes 2 and 3.

[0139] The literature-known 5,6,6a,7-tetrahydroindolo[1,2-a]quinolines (see J.-S. Li et al., Chem. Commun., 2018, 54, 9151) and 6,6a,7,8-tetrahydro-5H-dibenzo[c,f]-quinolizines (see M. Warsitz et al., Eur. J. Org. Chem. 2020, 6997) can be sequentially halogenated according to the methods described in Scheme 2, Scheme 3 and Scheme 5 and then further functionalized to the compounds of the invention by CC coupling (Suzuki, Negishi, Sonogashira, Grignard Cross, etc.) or CN coupling (Buchwald-Hartwig, Ullmann, etc.), see Scheme 6.

[0140] Scheme 6:

[0141]

[0142] The 10a,11-dihydro-10a-sila-10H-indolo[1,2-a]indoles can be prepared starting from bis(2-alkylphenyl)amines and primary alkyl- or arylsilanes according to Q. Li et al., Angew. Chem. Int. Ed. 2014, 53, 8471, see Scheme 7.

[0143] The 6,6a,7,8-tetrahydro-5-sila-5H-dibenzo[c,f]quinolizines can be prepared starting from bis(2-alkenylphenyl)amines and primary alkyl- or arylsilanes according to Z.-Y. Liu et al., Angew. Chem. Int. Ed. 2017, 56, 5817 and H. Nagashima et al., Organometallics, 1989, 8, 10 (see Scheme 8).

[0144]

[0145] The meaning of the symbols used in the schemes presented above corresponds essentially to that defined for formula (I), although for reasons of clarity, numbering and a complete representation of all symbols have been omitted.

[0146] Germanium compounds can be obtained in particular according to the processes shown in Schemes 7 and 8.

[0147] A further object of the present invention is therefore a process for preparing a compound according to the invention, wherein a heterocyclic basic structure having an amino group is synthesized and at least one aromatic or heteroaromatic radical is introduced, preferably by means of a nucleophilic aromatic substitution reaction or a coupling reaction.

[0148] By these processes, optionally followed by purification, such as recrystallization or sublimation, the compounds according to the invention can be obtained in high purity, preferably more than 99% (determined by 1 H-NMR and / or HPLC).

[0149] The compounds of the invention can also be mixed with a polymer. It is also possible to covalently incorporate these compounds into a polymer. This is particularly possible with compounds substituted by reactive leaving groups, such as bromine, iodine, chlorine, boronic acid, or boronic acid esters, or by reactive, polymerizable groups, such as olefins or oxetanes. These can be used as monomers to produce corresponding oligomers, dendrimers, or polymers. The oligomerization or polymerization preferably takes place via the halogen functionality or the boronic acid functionality, or via the polymerizable group, respectively. It is also possible to crosslink the polymers via such groups. The compounds and polymers of the invention can be used as crosslinked or uncrosslinked layers.

[0150] The invention therefore further provides oligomers, polymers or dendrimers comprising one or more of the above-listed structures of the formula (I) and preferred embodiments of this formula or compounds according to the invention, wherein one or more bonds of the compounds according to the invention or of the structures of the formula (I) and preferred embodiments of this formula to the polymer, oligomer or dendrimer are present. Depending on the linkage of the structures of the formula (I) and preferred embodiments of this formula or of the compounds, these therefore form a side chain of the oligomer or polymer or are linked in the main chain. The polymers, oligomers or dendrimers can be conjugated, partially conjugated or non-conjugated. The oligomers or polymers can be linear, branched or dendritic.The same preferences as described above apply to the repeating units of the compounds according to the invention in oligomers, dendrimers and polymers.

[0151] To prepare the oligomers or polymers, the monomers according to the invention are homopolymerized or copolymerized with other monomers. Copolymers are preferred, wherein the units according to formula (I) or the preferred embodiments described above and below are present in amounts of 0.01 to 99.9 mol%, preferably 5 to 90 mol%, particularly preferably 20 to 80 mol%. Suitable and preferred comonomers which form the polymer backbone are selected from fluorenes (e.g. according to EP 842208 or WO 2000 / 022026), spirobifluorenes (e.g. according to EP 707020, EP 894107 or WO 2006 / 061181), para-phenylenes (e.g. according to WO 92 / 18552), carbazoles (e.g. according to WO 2004 / 070772 or WO 2004 / 113468), thiophenes (e.g. according to EP 1028136), dihydrophenanthrenes (e.g. according to WO 2005 / 014689), cis- and trans-indenofluorenes (e.g. according to WO 2004 / 041901 or WO 2004 / 113412), ketones (e.g. according to WO 2005 / 040302), phenanthrenes (e.g.according to WO 2005 / 104264 or WO 2007 / 017066) or several of these units. The polymers, oligomers, and dendrimers may contain further units, for example hole-transport units, in particular those based on triarylamines, and / or electron-transport units.

[0152] Of particular interest are also compounds according to the invention that are characterized by a high glass transition temperature. In this context, particular preference is given to compounds according to the invention comprising structures according to formula (I) or the preferred embodiments described above and below, which have a glass transition temperature of at least 70°C, more preferably of at least 110°C, most preferably of at least 125°C, and especially preferably of at least 150°C, determined according to DIN 51005 (version 2005-08).

[0153] For processing the compounds of the invention from the liquid phase, for example by spin coating or printing processes, formulations of the compounds of the invention are required. These formulations can be, for example, solutions, dispersions, or emulsions. It may be preferred to use mixtures of two or more solvents for this purpose. Suitable and preferred solvents are, for example, toluene, anisole, o-, m- or p-xylene, methyl benzoate, mesitylene, tetralin, veratrole, THF, methyl-THF, THP, chlorobenzene, dioxane, phenoxytoluene, in particular 3-phenoxytoluene, (-)-fenchone, 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, 1-methylnaphthalene, 2-methylbenzothiazole, 2-phenoxyethanol, 2-pyrrolidinone, 3-methylanisole, 4-methylanisole, 3,4-dimethylanisole, 3,5-dimethylanisole, acetophenone, a-terpineol, benzothiazole, butylbenzoate, cumene, cyclohexanol, cyclohexanone, Cyclohexylbenzene, decalin, dodecylbenzene, ethyl benzoate, indane, NMP,p-Cymene, phenetole, 1,4-diisopropylbenzene, dibenzyl ether, diethylene glycol butylmethyl ether, triethylene glycol butylmethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, diethylene glycol monobutyl ether, tripropylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 2-isopropylnaphthalene, pentylbenzene, hexylbenzene, heptylbenzene, octylbenzene, 1,1-bis(3,4-dimethylphenyl)ethane, 2-methylbiphenyl, 3-methylbiphenyl, 1-methylnaphthalene, 1-ethylnaphthalene, ethyl octanoate, diethyl sebacate, octyloctanoate, heptylbenzene, menthyl isovalerate, cyclohexylhexanoate or mixtures of these solvents.

[0154] The present invention therefore further provides a formulation or a composition comprising at least one compound according to the invention and at least one further compound. The further compound can, for example, be a solvent, in particular one of the abovementioned solvents or a mixture of these solvents. If the further compound comprises a solvent, this mixture is referred to herein as a formulation. However, the further compound can also be at least one further organic or inorganic compound which is likewise used in the electronic device, for example an emitter and / or a matrix material, wherein these compounds differ from the compounds according to the invention. Suitable emitters and matrix materials are listed below in connection with the organic electroluminescent device. The further compound can also be polymeric.

[0155] Yet another subject of the present invention is therefore a composition comprising at least one compound of formula (I) where the symbols used have the meanings given above, where the structure of formula (I) does not comprise a six-membered ring in which a boron atom is arranged para to a nitrogen atom, preferably at least one compound according to the invention or an oligomer, polymer, or dendrimer comprising structures according to formula (I) and at least one further organically functional material. Functional materials are generally the organic or inorganic materials that are introduced between the anode and cathode. The organically functional material is preferably selected from the group consisting of fluorescent emitters, phosphorescent emitters, emitters that exhibit TADF (thermally activated delayed fluorescence), host materials, electron-transport materials, electron-injection materials, hole-conductor materials, hole-injection materials, electron-blocking materials, and hole-blocking materials, preferably host materials.

[0156] Another object of the present invention is the use of a compound according to formula (I) wherein the symbols used have the meanings given above, wherein the structure of formula (I) does not comprise a six-membered ring in which a boron atom is arranged in the para-position to a nitrogen atom, preferably a compound according to the invention or an oligomer, polymer or dendrum comprising structures according to formula (I) in an electronic device, preferably in an organic electroluminescent device, preferably as host material, hole conductor material, hole injection material or electron blocking material.

[0157] Furthermore, it can be provided that a compound according to formula (I), preferably a compound according to the invention, is used as host material, hole conductor material, hole injection material or electron blocking material and this compound according to the invention comprises at least one hole transport group, wherein preferred hole transport groups have been defined above.

[0158] Furthermore, it can be provided that a compound according to formula (I), preferably a compound according to the invention, is used as host material and this compound according to the invention comprises both at least one hole transport group and at least one electron transport group, wherein preferred hole transport groups and / or electron transport groups have been defined previously.

[0159] A further subject of the present invention is an electronic device comprising at least one compound of formula (I) where the symbols used have the meanings given above, where the structure of formula (I) does not comprise a six-membered ring in which a boron atom is arranged para to a nitrogen atom, preferably at least one compound according to the invention or an oligomer, polymer, or dendrimer comprising structures according to formula (I). An electronic device within the meaning of the present invention is a device which contains at least one layer containing at least one organic compound. The component can also contain inorganic materials or layers composed entirely of inorganic materials.

[0160] Particularly preferably, the electronic device is selected from the group consisting of organic electroluminescent devices (OLEDs, sOLEDs, PLEDs, LECs, etc.), preferably organic light-emitting diodes (OLEDs), organic light-emitting diodes based on small molecules (sOLEDs), organic light-emitting diodes based on polymers (PLEDs), light-emitting electrochemical cells (LECs), organic laser diodes (O-lasers), “organic plasmon emitting devices” (DM Koller et al., Nature Photonics 2008, 1- 4); organic integrated circuits (O-ICs), organic field-effect transistors (O-FETs), organic thin-film transistors (O-TFTs), organic light-emitting transistors (O-LETs), organic solar cells (O-SCs), organic optical detectors, organic photoreceptors, organic field-quench devices (O-FQDs) and organic electrical sensors, preferably organic electroluminescent devices (OLEDs, sOLEDs, PLEDs, LECs, etc.), particularly preferably organic light-emitting diodes (OLEDs), organic light-emitting diodes based on small molecules (sOLEDs), organic light-emitting diodes based on polymers (PLEDs), in particular phosphorescent OLEDs.

[0161] The organic electroluminescent device contains a cathode, an anode, and at least one emitting layer. In addition to these layers, it may contain further layers, for example, one or more hole-injection layers, hole-transport layers, hole-blocking layers, electron-transport layers, electron-injection layers, exciton-blocking layers, electron-blocking layers, and / or charge-generation layers. Interlayers, which, for example, have an exciton-blocking function, may also be inserted between two emitting layers. It should be noted, however, that not all of these layers are necessarily present. The organic electroluminescent device may contain one emitting layer or it may contain multiple emitting layers.If multiple emission layers are present, they preferably have a total of multiple emission maxima between 380 nm and 750 nm, resulting in overall white emission. This means that different emitting compounds that can fluoresce or phosphoresce are used in the emitting layers. Systems with three emitting layers are particularly preferred, with the three layers exhibiting blue, green, and orange or red emission. The organic electroluminescent device according to the invention can also be a tandem electroluminescent device, particularly for white-emitting OLEDs.

[0162] The compound according to formula (I), preferably the compound according to the invention, can be used in different layers, depending on the precise structure. Preference is given to an organic electroluminescent device comprising a compound according to formula (I) or the preferred embodiments described above in an emitting layer as a host material for fluorescent emitters, phosphorescent emitters or for emitters which exhibit TADF (thermally activated delayed fluorescence), in particular for phosphorescent emitters. Furthermore, the compound according to the invention can also be used in a hole transport layer, hole injection layer and / or in an exciton blocking layer. The compound according to the invention is particularly preferably used as a matrix material for phosphorescent emitters, in particular for red, orange, green, yellow or blue phosphorescent emitters, in an emitting layer, as a hole transport orElectron-blocking material in a hole-transport or electron-blocking layer, or hole-injection material in a hole-injection layer. The suitability of the various compounds according to formula (I) has been previously explained in connection with preferred uses.

[0163] When the compound according to the invention is used as a matrix material for a phosphorescent compound in an emitting layer, it is preferably used in combination with one or more phosphorescent materials (triplet emitters).

[0164] For the purposes of this invention, phosphorescence refers to luminescence from an excited state with higher spin multiplicity, i.e., a spin state > 1, in particular from an excited triplet state. For the purposes of this application, all luminescent complexes with transition metals or lanthanides, in particular all iridium, platinum, and copper complexes, are to be considered phosphorescent compounds.

[0165] The mixture of the compound according to the invention and the emitting compound contains between 99 and 1 vol.%, preferably between 98 and 10 vol.%, particularly preferably between 97 and 60 vol.%, in particular between 95 and 80 vol.% of the compound according to the invention, based on the total mixture of emitter and matrix material. Accordingly, the mixture contains between 1 and 99 vol.%, preferably between 2 and 90 vol.%, particularly preferably between 3 and 40 vol.%, in particular between 5 and 20 vol.% of the emitter, based on the total mixture of emitter and matrix material.

[0166] In one embodiment of the invention, the compound according to the invention is used as the only matrix material (“single host”) for the phosphorescent emitter.

[0167] A further embodiment of the present invention is the use of the compound according to the invention as a matrix material for a phosphorescent emitter in combination with another matrix material. Suitable matrix materials that can be used in combination with the compounds according to the invention are aromatic ketones, aromatic phosphine oxides or aromatic sulfoxides or sulfones, e.g., according to WO 2004 / 013080, WO 2004 / 093207, WO 2006 / 005627, or WO 2010 / 006680, triarylamines, carbazole derivatives, e.g., B. CBP (N,N-biscarbazolylbiphenyl) or those in WO 2005 / 039246, US 2005 / 0069729, JP 2004 / 288381, EP 1205527, WO 2008 / 086851 or WO 2013 / 041176, indolocarbazole derivatives, e.g. according to WO 2007 / 063754 or WO 2008 / 056746, indenocarbazole derivatives, e.g. according to WO 2010 / 136109, WO 2011 / 000455, WO 2013 / 041176 or WO 2013 / 056776, azacarbazole derivatives, e.g. B. according to EP 1617710, EP 1617711 , EP 1731584, JP 2005 / 347160, bipolar matrix materials, e.g.according to WO 2007 / 137725, silanes, e.g. according to WO 2005 / 111172, azaboroles or boronate esters, e.g. according to WO 2006 / 117052, triazine derivatives, e.g. according to WO 2007 / 063754, WO 2008 / 056746, WO 2010 / 015306, WO 2011 / 057706, WO 2011 / 060859 or WO 2011 / 060877, zinc complexes, e.g. according to EP 652273 or WO 2009 / 062578, diazasilole or tetraazasilole derivatives, e.g. according to WO 2010 / 054729, diazaphosphole derivatives, e.g. B. according to WO 2010 / 054730, bridged carbazole derivatives, e.g. according to WO 2011 / 042107, WO 2011 / 060867, WO 2011 / 088877 and WO 2012 / 143080, triphenylene derivatives, e.g. according to WO 2012 / 048781, dibenzofuran derivatives, e.g. according to WO 2015 / 169412, WO 2016 / 015810, WO 2016 / 023608, WO 2017 / 148564 or WO 2017 / 148565 or biscarbazoles, e.g. according to JP 3139321 B2.

[0168] In a preferred embodiment, a compound containing a structure / compound according to formula (I) or the preferred embodiments described above, which is used as a host material, is preferably used in combination with one or more phosphorescent materials (triplet emitters) and / or a compound that represents a TADF (thermally activated delayed fluorescence) host material. This preferably forms a hyperfluorescence system as described in WO 2012 / 133188 and / or a hyperphosphorescence system as described in US 2017271611. This combination represents a preferred composition according to the present invention.

[0169] WO 2015 / 091716 A1 and WO 2016 / 193243 A1 disclose OLEDs containing both a phosphorescent compound and a fluorescent emitter in the emission layer, with the energy being transferred from the phosphorescent compound to the fluorescent emitter (hyperphosphorescence). In this context, the phosphorescent compound therefore behaves like a host material. As those skilled in the art know, host materials have higher singlet and triplet energies than the emitters, so that the energy of the host material is transferred to the emitter as optimally as possible. The systems disclosed in the prior art exhibit precisely such an energy relationship.

[0170] Preferred emitters that can be used in combination with a compound according to the invention are described, inter alia, by Sungho Nam et al., Adv. Sci. 2021, 2100586 and Eungdo Kin et al., Sci. Adv. 2022, 8, eabq 1641. Furthermore, preferred triplet emitters or triplet emitter classes, also called sensitizers in connection with hyperfluorescence systems, are described in EP 3 435 438 A2, with emitters 2 and 3 on page 21 being preferred; in CN 109111487, with the compounds set out on pages 76 and 77 being preferred; in US 2020 / 0140471, with the compounds set out on pages 166 to 175 being preferred; in KR2020108705, wherein the compounds set forth on pages 8 to 14 are preferred; in US 2019 / 0119312, wherein the compounds set forth on pages 114 to 121 are preferred; and in US 2020 / 0411775, wherein the compounds set forth on pages 123 to 128 are preferred.Furthermore, preferred fluorescent emitters or classes of fluorescent emitters are set out in WO 2021 / 090932, wherein the compounds set out on pages 129 to 133, 157 to 166, 171 to 187, 200 to 211, 222 to 227, 236 to 252, 255 are preferred; in WO 2020 / 054676, wherein the compounds set out on pages 44 to 104 are preferred; in WO 2020 / 017931, wherein the compounds set out on pages 17 to 39 are preferred; in WO 2020 / 218079, wherein the compounds set out on pages 64 to 258 are preferred; in WO 2018 / 212169, wherein the compounds set out on pages 33 to 42 are preferred. in WO 20192 / 35452, wherein the compounds set forth on pages 46 to 168 are preferred; in US 10,249,832, wherein the compounds set forth on pages 19 to 106 are preferred; and in WO 2021 / 014001, wherein the compounds set forth on pages 107 to 129 are preferred.

[0171] Likewise, another phosphorescent emitter, which emits at a shorter wavelength than the actual emitter, can be present in the mixture as a co-host. Particularly good results are achieved when a red-phosphorescent emitter is used as the emitter and a yellow-phosphorescent emitter is used as the co-host in combination with the compound according to the invention.

[0172] Furthermore, a compound can be used as co-host which does not participate, or does not participate to a significant extent, in charge transport, as described, for example, in WO 2010 / 108579. In particular, compounds which have a large band gap and themselves do not participate, or at least do not participate to a significant extent, in the charge transport of the emitting layer are suitable as co-matrix material in combination with the compound according to the invention. Such materials are preferably pure hydrocarbons. Examples of such materials can be found, for example, in WO 2009 / 124627 or WO 2010 / 006680. In this context, it should be noted that compounds according to the invention without special functional groups, for example hole transport groups and / or electron transport groups, have advantageous properties.

[0173] Particularly suitable phosphorescent compounds (= triplet emitters) are compounds that emit light upon suitable excitation, preferably in the visible range, and also contain at least one atom with an atomic number greater than 20, preferably greater than 38 and less than 84, particularly preferably greater than 56 and less than 80, in particular a metal with this atomic number. Compounds containing copper, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver, gold, or europium are preferably used as phosphorescent emitters, in particular compounds containing iridium or platinum.

[0174] Examples of the emitters described above can be found in the applications WO 00 / 70655, WO 2001 / 41512, WO 2002 / 02714, WO 2002 / 15645, EP 1191613, EP 1191612, EP 1191614, WO 05 / 033244, WO 05 / 019373, US 2005 / 0258742, WO 2009 / 146770, WO 2010 / 015307, WO 2010 / 031485, WO 2010 / 054731, WO 2010 / 054728, WO 2010 / 086089, WO 2010 / 099852, WO 2010 / 102709, WO 2011 / 032626, WO 2011 / 066898, WO 2011 / 157339, WO 2012 / 007086, WO 2014 / 008982, WO 2014 / 023377, WO 2014 / 094961, WO 2014 / 094960, WO 2015 / 036074, WO 2015 / 104045, WO 2015 / 117718, WO 2016 / 015815, WO 2016 / 124304, WO 2017 / 032439 and WO 2018 / 011186. In general, all phosphorescent complexes as used according to the prior art for phosphorescent electroluminescent devices and as known to the person skilled in the art in the field of organic electroluminescence are suitable, and the person skilled in the art can use further phosphorescent complexes without inventive step.

[0175] Examples of phosphorescent dopants are listed in the following table.

[0176]

[0177] The compounds of the invention are also particularly suitable as matrix materials for phosphorescent emitters in organic electroluminescent devices, as described, for example, in WO 98 / 24271, US 2011 / 0248247, and US 2012 / 0223633. In these multi-color display components, an additional blue emission layer is vapor-deposited over the entire surface of all pixels, even those with a color other than blue.

[0178] In a further embodiment of the invention, the organic electroluminescent device according to the invention does not contain a separate hole injection layer and / or hole transport layer and / or hole blocking layer and / or electron transport layer, i.e. the emitting layer directly adjoins the hole injection layer or the anode, and / or the emitting layer directly adjoins the electron transport layer or the electron injection layer or the cathode, as described, for example, in WO 2005 / 053051. Furthermore, it is possible to use a metal complex that is the same as or similar to the metal complex in the emitting layer as a hole transport or hole injection material directly adjacent to the emitting layer, as described, for example, in WO 2009 / 030981.

[0179] In the further layers of the organic electroluminescent device according to the invention, all materials can be used as they are commonly used according to the prior art. Therefore, the person skilled in the art can, without inventive step, use all materials known for organic electroluminescent devices in combination with the compounds according to the invention according to formula (I) or the preferred embodiments described above. Furthermore, an organic electroluminescent device is preferred, characterized in that one or more layers are coated using a sublimation process. The materials are coated in vacuum sublimation systems at an initial pressure of less than 10' 5 mbar, preferably less than 10' 6 mbar. However, it is also possible that the initial pressure is even lower, for example less than 10- 7 mbar.

[0180] Also preferred is an organic electroluminescent device, characterized in that one or more layers are coated using the OVPD (Organic Vapor Phase Deposition) process or by means of carrier gas sublimation. The materials are sublimated at a pressure between 10' 5 mbar and 1 bar. A special case of this process is the OVJP (Organic Vapor Jet Printing) process, in which the materials are applied directly through a nozzle and thus structured.

[0181] Also preferred is an organic electroluminescent device characterized in that one or more layers are produced from solution, such as by spin coating, or by any printing process, such as screen printing, flexographic printing, offset printing, LITI (Light Induced Thermal Imaging, thermal transfer printing), inkjet printing, or nozzle printing. Soluble compounds are required for this, which are obtained, for example, by suitable substitution.

[0182] Formulations for applying a compound according to formula (I) or the preferred embodiments thereof set out above are novel. A further subject of the present invention is therefore a formulation comprising at least one solvent and a compound according to formula (I) or the preferred embodiments thereof set out above.

[0183] Furthermore, hybrid processes are possible, in which, for example, one or more layers are applied from solution and one or more further layers are vapor-deposited. These processes are generally known to the person skilled in the art and can be applied by him without inventive step to organic electroluminescent devices containing the compounds of the invention.

[0184] The compounds according to the invention and the organic electroluminescent devices according to the invention are distinguished from the prior art in particular by improved efficiency and / or operating voltage. Furthermore, these compounds and the organic electroluminescent devices obtainable therefrom exhibit an improved lifetime. In a particular variant, the compounds according to the invention and the organic electroluminescent devices according to the invention are distinguished from the prior art in particular by a low refractive index (RI). Furthermore, preferred compounds according to the invention exhibit a high triplet Ti level, so that these compounds are particularly suitable as host material for blue-emitting triplet emitters.

[0185] The electronic devices according to the invention, in particular organic electroluminescent devices, are characterized by one or more of the following surprising advantages over the prior art:

[0186] 1. Electronic devices, in particular organic electroluminescent devices comprising compounds of the formula (I) or the preferred embodiments set out above and below, in particular as matrix material or as hole-conducting materials, have excellent efficiency. Compounds of the invention according to formula (I) or the preferred embodiments set out above and below result in a low operating voltage when used in electronic devices. 2. Electronic devices, in particular organic electroluminescent devices comprising compounds of the formula (I) or the preferred embodiments set out above and below, in particular as matrix material or as hole-conducting materials, have a very good lifetime. These compounds result in particular in low roll-off, i.e. a low drop in the power efficiency of the device at high luminance levels.

[0187] 3. The compounds according to the invention according to formula (I) or the preferred embodiments described above and below show a very high stability and lifetime.

[0188] 4. Electronic devices, in particular organic electroluminescent devices comprising compounds according to formula (I) or the preferred embodiments described above and below, in particular as matrix material or as hole-conducting materials, have a high T1 level.

[0189] 5. Using compounds according to formula (I) or the preferred embodiments described above and below, the formation of optical loss channels can be avoided in electronic devices, particularly organic electroluminescent devices. As a result, these devices are characterized by high PL and thus high EL efficiency of emitters and excellent energy transfer from the matrices to dopants.

[0190] 6. Compounds according to formula (I) or the preferred embodiments described above and below have excellent glass film formation.

[0191] 7. Compounds according to formula (I) and the preferred embodiments described above and below form very good films from solutions. These aforementioned advantages are not accompanied by an excessive deterioration in other electronic properties.

[0192] It should be noted that variations of the embodiments described in the present invention fall within the scope of this invention. Any feature disclosed in the present invention may, unless explicitly excluded, be replaced by alternative features serving the same, equivalent, or similar purpose. Thus, unless otherwise stated, any feature disclosed in the present invention is to be considered an example of a generic series or an equivalent or similar feature.

[0193] All features of the present invention may be combined with each other in any way, unless certain features and / or steps are mutually exclusive. This applies in particular to preferred features of the present invention. Likewise, features of non-essential combinations may be used separately (and not in combination).

[0194] It should further be noted that many of the features, and in particular those of the preferred embodiments of the present invention, are inventive in their own right and should not be considered merely part of the embodiments of the present invention. Independent protection may be sought for these features in addition to or alternatively to any presently claimed invention.

[0195] The teaching of technical action disclosed in the present invention can be abstracted and combined with other examples.

[0196] The invention is further illustrated by the following examples, without intending to limit it. From these descriptions, one skilled in the art can practice the invention within the entire disclosed scope and, without inventive step, prepare further compounds according to the invention and use them in electronic devices or apply the method according to the invention.

[0197] Examples:

[0198] Unless otherwise stated, the following syntheses are carried out under a protective gas atmosphere in dried solvents. The metal complexes are also handled in the absence of light or under yellow light. The solvents and reagents can be obtained, for example, from Sigma-ALDRICH or ABCR. The respective information in square brackets or the numbers given for individual compounds refer to the CAS numbers of the known compounds. For compounds that can exhibit multiple enantiomeric, diastereomeric, or tautomeric forms, one form is shown as a representative example.

[0199]

[0200] LS5 and LS6 are obtained analogously to ES Sherman et al., Adv. Synth. Catal. 2009, 351 , 467, compound 4g and 4h, using 3-chlorophenylboronic acid [63503-60-6].

[0201] A) Representation of synthons S

[0202] A well-stirred solution of 20.7 g (100 mmol) LS1 in 500 ml dichloromethane (DCM) cooled to 0 °C is treated in portions with

[0203] 17.8 g (100 mmol) of N-bromosuccinimide (NBS) are added. The mixture is stirred for 2 h at 0 °C, allowed to warm to room temperature overnight, washed three times with 300 ml of water each time, once with 300 ml of saturated sodium chloride solution, and dried over magnesium sulfate. The drying agent is removed by filtration, the filtrate is evaporated to dryness, and the residue is chromatographed (Torrent column machine from A. Semrau). Yield:

[0204] 21.9 g (76 mmol) 76%; Purity: approx. 97% n. 1 H-NMR.

[0205] Analogously, the following compounds can be obtained by adjusting the stoichiometry of the reactants.

[0206] B) Preparation of the compounds according to the invention B Example B1:

[0207]

[0208] A well-stirred solution of 28.6 g (100 mmol) of S1, 39.6 g (110 mmol) of 9,9'-spirobi[9H-fluoren]-2-ylboronic acid [236389-21-2], 42.4 g (200 mmol) of tripotassium phosphate [7778-53-2], 1.16 g (1 mmol) of tetrakis(triphenylphosphine)palladium(O) [14221-01-3], 300 ml of toluene, 100 ml of dioxane, and 300 ml of water was heated under reflux for 16 h. After cooling, the organic phase was separated, washed three times with 300 ml of water each time, once with 300 ml of saturated sodium chloride solution, and dried over magnesium sulfate. The desiccant is filtered off, the filtrate is concentrated to dryness, and the residue is chromatographed (a Torrent column system from A. Semrau). Further purification of the crude product is carried out by chromatography and / or repeated hot extraction crystallization (common organic solvents or combinations thereof, preferably acetonitrile-DCM, 1:3 to 3:1 vv) as well as fractional sublimation or annealing under high vacuum. Yield: 36.0 g (69 mmol) 69%; Purity: approximately 99.9% by HPLC.

[0209] Analogously, the following compounds can be prepared by adjusting the stoichiometry of the reactants, whereby when using chlorides such as LS5 or LS6, 1 mmol palladium acetate and 2 mmol S-Phos are used. A solution of 20.7 g (100 mmol) of S1 and 38.6 g (120 mmol) of bis-p-biphenylamine [102113-98-4] in 500 ml of toluene is treated with 4.0 ml (4 mmol) of a 1.0 M tri-tert-butylphosphine solution in toluene, 449 mg (2 mmol) of palladium acetate, and 15.4 g of sodium tert-butoxide (160 mmol) and heated under reflux for 16 h. The reaction mixture is filtered while still warm through a bed of Celite pre-slurried with toluene. The filtrate is concentrated in vacuo, and the residue is stirred with 300 ml of hot ethanol. The crude product is purified by hot extraction crystallization (typical organic solvents, preferably acetonitrile or acetonitrile / dichloromethane mixtures 4:1 to 1:4 vv) or chromatography (Torrent column machine from A. Semrau) and by fractional sublimation in vacuum (p ~ 10 -5 mbar, T ~ 280 °C). Yield: 40.0 g (72 mmol) 72%. Purity by HPLC >99.9%.

[0210]

[0211] A mixture of 36.2 g (100 mmol) S101, 14.2 g (110 mmol) 2-chlorophenol [95-57-8], 42.5 g (200 mmol) anhydrous tripotassium phosphate, 1.23 g (10 mmol) picolinic acid, 952 mg (5 mmol) copper(I) iodide, 100 g glass beads (3 mm diameter) and 300 ml DMSO is stirred for 20 h at 100° C. The filtrate is filtered off while still hot with suction through a bed of Celite pre-slurried with DMSO, the filtrate is largely concentrated, the residue is stirred with 300 ml of a methanol / water mixture (1:1 vv) while hot, the crude product is filtered off with suction, washed twice with 50 ml of methanol each time, dried in vacuo and recrystallized from acetonitrile. Yield: 25.2 g (62 mmol), 62%; Purity: approximately 95%. 1 H-NMR.

[0212] B) Cyclization

[0213] Procedure analogous to Campeau et al., J. Am. Chem. Soc., 2006, 128, 593. A mixture of 41.0 g (100 mmol) B700 (step A), 27.6 g (200 mmol) potassium carbonate, 3.68 g (10 mmol) tricyclohexylphosphonium tetrafluoroborate [58656-04-5], 1.12 g (5 mmol) palladium(II) acetate, 100 g glass beads (3 mm diameter) and 300 ml dimethylacetamide (DMA) is stirred for 20 h at 140°C. The mixture is filtered off while still hot through a Celite bed pre-slurried with DMA, the filtrate is largely concentrated, the residue is stirred hot with 300 ml of a methanol / water mixture (1:1 vv), the crude product is filtered off while still hot, washed twice with 50 ml of methanol each time, and dried in vacuo. The regioisomers B700a and B700b are separated by chromatography (Torrent column system from A. Semrau). Further purification of the individual regioisomers is carried out by repeated hot extraction crystallization (conventional organic solvents or chromatography).combinations thereof, preferably acetonitrile-DCM, 1:3 to 3:1 vv) and fractional sublimation or annealing under high vacuum. Yield: B700a: 9.7 g (26 mmol) 26%; Purity: approx. 99.9% by HPLC.

[0214] B700b: 12.5 g (33 mmol) 33%; Purity: approx. 99.9% according to HPLC.

[0215] Synthesis analogous to Q. Li et al., Angew. Chem. Int. Ed. 2014, 53, 8471, compound 6a. Instead of 2,5-dimethyl-N-methylaniline, 3-methyl-N-(3-methyl[1,1′-biphenyl]-4-yl)[1,1′-biphenyl]-4-amine [2410698-02-9] (10 mmol) was used, and neo-pentylsilane [1186524-08-2] was used instead of diethylsilane. The other reagents were adjusted accordingly. Purification was carried out by chromatography and repeated hot extraction crystallization (conventional organic solvents or combinations thereof, preferably acetonitrile-DCM, 1:3 to 3:1 vv) and fractional sublimation or annealing under high vacuum. Yield: 1.7 g (3.8 mmol), 38%; Purity: approximately >99.9% by HPLC.

[0216]

[0217] Preparation according to Z.-Y. Liu et al., Angew. Chem. Int. Ed. 2017, 56, 5817, Step 1 coupling of 2.21 g (10 mmol) 2-ethenyl-N-(2-ethenylphenyl)benzenamine [2172900-84-2] with 1.84 g (10 mmol) biphenylsilane [51919-05-2], according to the procedure footnote 17, then Step 2 intermolecular bis-hydrosilylation according to H. Nagashima et al., Organometallics, 1989, 8, 10, Example 7. Purification is carried out in each case by chromatography and repeated hot extraction crystallization (usual organic solvents or combinations thereof, preferably acetonitrile-DCM, 1:3 to 3:1 vv) and fractional sublimation or

[0218] Annealed under high vacuum. Yield: 942 mg (3.1 mmol), 31%; Purity: approximately >99.9% by HPLC.

[0219]

[0220] Example: Production of OLEDs

[0221] 1) Vacuum-processed devices:

[0222] The production of OLEDs according to the invention as well as OLEDs according to the prior art is carried out according to a general process according to WO 2004 / 058911 , which is adapted to the conditions described here (layer thickness variation, materials used).

[0223] The following examples present the results of various OLEDs. Cleaned glass plates (cleaned in a Miele laboratory dishwasher using Merck Extran cleaner) coated with 50 nm thick structured ITO (indium tin oxide) are pretreated with UV ozone for 25 minutes (UV ozone generator PR-100, UVP). These coated glass plates form the substrates onto which the OLEDs are applied.

[0224] 1a) Blue Fluorescence OLED Components - BF:

[0225] The compounds B according to the invention can be used in the hole injection layer (HIL), hole transport layer (HTL), and electron blocking layer (EBL). All materials are thermally vapor-deposited in a vacuum chamber. The emission layer (EML) always consists of at least one matrix material (host material) SMB (see Table 1) and an emitting dopant (dopant, emitter) D, which is admixed to the matrix material(s) by co-evaporation in a specific volume fraction. A specification such as SMB:D (97:3%) means that the SMB material is present in the layer in a volume fraction of 97% and the dopant D in a volume fraction of 3%. Analogously, the electron transport layer can also consist of a mixture of two materials, see Table 1. The materials used to produce the OLEDs are shown in Table 5 or refer to the previously presented synthesis examples.

[0226] The OLEDs are characterized as standard. For this purpose, the electroluminescence spectra, current efficiency (measured in cd / A), power efficiency (measured in λ / W), and external quantum efficiency (EQE, measured in percent) are determined as a function of luminance, calculated from current-voltage-luminance characteristics (IUL characteristics) assuming a Lambertian curve. The EQE is expressed in (%) and the voltage in (V) at a luminance of 1000 cd / m². 2 .

[0227] The OLEDs have the following layer structure:

[0228] Substrat

[0229] Hole injection layer (HIL) made of HTM1 doped with 5% NDP-9 (commercially available from Novaled), 20 nm. Hole transport layer (HTL), see Table 1. Electron blocking layer (EBL), see Table 1. Emission layer (EML), see Table 1. Electron transport layer (ETL), see Table 1. Electron injection layer (EIL) made of ETM2, 1 nm. Cathode made of aluminum, 100 nm. 1b) Phosphorescent OLED components: The compounds B according to the invention can be used as matrix material (host material) in the hole injection layer (HIL), the hole transport layer (HTL), the electron blocking layer (EBL), and in the emission layer (EML). For this purpose, all materials are thermally vapor-deposited in a vacuum chamber. The emission layer always consists of at least one or more matrix materials M and a phosphorescent dopant Ir, which is added to the matrix material(s) by co-evaporation in a specific volume fraction. A specification such as M1:M2:Ir (55%:35%:10%) means that the material M1 is present in the layer in a volume fraction of 55%, M2 in a volume fraction of 35%, and Ir in a volume fraction of 10%. Analogously, the electron transport layer can also consist of a mixture of two materials. The exact structure of the OLEDs can be found in Table 3.The materials used to manufacture the OLEDs are shown in Table 5 or refer to the synthesis examples presented above. The OLEDs are characterized as standard. For this purpose, the electroluminescence spectra, the current efficiency (measured in cd / A), the power efficiency (measured in lm / W), and the external quantum efficiency (EQE, measured in percent) are determined as a function of luminance, calculated from current-voltage-luminance characteristics (IUL characteristics) assuming a Lambertian radiation pattern. The EQE (%) and the voltage (V) are given at a luminance of 1000 cd / m². 2The OLEDs have the following layer structure: Substrate Hole injection layer (HIL) made of HTM1 doped with 5% NDP-9 (commercially available from Novaled), 20 nm Hole transport layer (HTL), see Table 3 Electron blocking layer (EBL), see Table 3 Emission layer (EML), see Table 3 Hole blocking layer (HBL), see Table 3 Electron transport layer (ETL), made of ETM1:ETM2 (50%:50%), 30 nm Electron injection layer (EIL) made of ETM2, 1 nm Cathode made of aluminum, 100 nm 15 Table 4: Results of phosphorescent OLED devices

[0230]

[0231] Table 5: Structural formulas of the materials used

Claims

Patent claims 1 . A compound comprising at least one structure of formula (I), where the symbols are: Z represents, the same or different at each occurrence, C(R a ), Si(R b ) or Ge(R b ); W 1 represents, at each occurrence, the same or different, a group -C(R C ) 2-, -C(R C )2-C(R c )2- or -C(R C )2-C(R c )2-C(R c )2-; W 2 represents, at each occurrence, the same or different, a group -C(R d ) 2-, -C(R d )2-C(R d )2- or -C(R d )2-C(R c )2-C(R d )2-; X represents, identically or differently at each occurrence, N or C(R), with the proviso that not more than two of the groups X in a cycle represent N; RH, D, OH, F, CI, Br, I, CN, NO2, N(Ar)2, N(R e )2, C(=O)N(Ar)2, C(=O)N(R e)2, C(Ar)3, C(R e )3, Si(Ar)3, Si(R e )3, Ge(Ar)3, Ge(R e )3, B(Ar)2, B(R e )2, C(=O)Ar, C(=O)R e , P(=O)(Ar)2, P(=O)(R e )2, P(Ar)2, P(R e )2, S(=O)Ar, S(=O)R e , S(=O)2Ar, S(=O)2R e , OSO2Ar, OSO2R e , a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 C atoms, where the alkyl, alkoxy, thioalkoxy, alkenyl or Alkynyl group with one or more radicals R e may be substituted, wherein one or more non-adjacent CH2 groups are substituted by R e C=CR e , C=C, Si(R e )2, C=O, C=S, C=Se, C=NR e , -C(=O)O-, -C(=O)NR e -, NR e , P(=O)(R e), - O-, -S-, SO or SO2, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each of which is substituted by one or more radicals R e may be substituted, or an arylalkyl or heteroarylalkyl group having 5 to 60 aromatic ring atoms and 1 to 10 C atoms in the alkyl radical, which may be substituted by one or more radicals R e may be substituted; two R radicals may also form a ring system with each other or at least one R radical of another group; Ar is at each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which is substituted by one or more radicals R e may be substituted, whereby two radicals Ar which bind to the same C-atom, Si-atom, N-atom, P-atom or B-atom may also be connected by a single bond or a bridge selected from B(R e ), C(R e )2, Si(R e )2, C=O, C=NR e, C=C(R e )2, 0, S, S=O, SO2, N(R e ), P(R e ) and P(=O)R e , be bridged together; R a is, at each occurrence, identically or differently, H, D, a straight-chain alkyl group having 1 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, where the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group is each substituted by one or more radicals R 1 may be substituted, wherein one or more non-adjacent CH2 groups are substituted by R 1 C=CR 1 , C=C, Si(R 1 )2, NR 1 , -O- or -S-, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each of which is substituted by one or more radicals R 1 may be substituted; a radical R a with another group form an aliphatic or heteroaliphatic ring system; R b is, at each occurrence, identically or differently, H, D, a straight-chain alkyl group having 1 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, where the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group is each substituted by one or more radicals R 1 may be substituted, wherein one or more non-adjacent CH2 groups are substituted by R 1 C=CR 1 , C=C, Si(R 1 )2, NR 1 , -O- or -S-, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each of which is substituted by one or more radicals R 1 may be substituted; a radical R b form an aliphatic or heteroaliphatic ring system with another group; R cis, at each occurrence, identically or differently, H, D, a straight-chain alkyl group having 1 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, where the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group is each substituted by one or more radicals R 1 may be substituted, wherein one or more non-adjacent CH2 groups are substituted by R 1 C=CR 1 , C=C, Si(R 1 )2, NR 1 , -O- or -S-, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each of which is substituted by one or more radicals R 1 can be substituted; two radicals R c also with each other or at least one residue R c another group form an aliphatic or heteroaliphatic ring system; R dis at each occurrence, identically or differently, H, D, a straight-chain alkyl group having 1 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, wherein the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group is each substituted by one or more radicals R 1 may be substituted, wherein one or more non-adjacent CH2 groups are substituted by R 1 C=CR 1 , C=C, Si(R 1 )2, NR 1 , -O- or -S-, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each of which is substituted by one or more radicals R 1 can be substituted; two radicals R d also with each other or at least one residue R d another group form an aliphatic or heteroaliphatic ring system; R eis, at each occurrence, the same or different: H, D, OH, F, CI, Br, I, CN, NO2, N(Ar')2, N(R 1 )2, C(=O)N(Ar')2, C(=O)N(R 1 )2, C(Ar')3, C(R 1 )3, Si(Ar')3, Si(R 1 )3, Ge(Ar')3, Ge(R 1 )3, B(Ar')2, B(R 1 )2, C(=O)Ar', C(=O)R 1 , P(=O)(Ar')2, P(=O)(R 1 )2, P(Ar')2, P(R 1 )2, S(=O)Ar', S(=O)R 1 , S(=O)2Ar', S(=O)2R 1 , OSO2Ar', OSO2R 1 , a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 C atoms, wherein the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group is each substituted with one or more radicals R 1 may be substituted, wherein one or more non-adjacent CH2 groups are substituted by R 1 C=CR 1 , C=C, Si(R 1 )2, Ge(R 1)2, C=O, C=S, C=Se, C=NR 1 , -C(=O)O-, -C(=O)NR 1 - NR 1 , P(=O)(R 1 ), -O-, -S-, SO or SO2, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each of which is substituted by one or more radicals R 1 may be substituted, or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R 1 can be substituted; two radicals R e also with each other or at least one radical R e another group form a ring system; Ar' is at each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which is substituted with one or more radicals R 1may be substituted, whereby two radicals Ar' which bind to the same C-atom, Si-atom, N-atom, P-atom or B-atom may also be substituted by a single bond or a bridge selected from B(R 1 ), C(R 1 )2, Si(R 1 )2, C=O, C=NR 1 , C=C(R 1 )2, 0, S, S=O, SO2, N(R 1 ), P(R 1 ) and P(=O)R 1 , be bridged together; R 1 is, at each occurrence, the same or different: H, D, F, CI, Br, I, CN, NO2, N(Ar”)2, N(R 2 )2, C(=O)Ar”, C(=O)R 2 , P(=O)(Ar”)2, P(Ar”)2, B(Ar”)2, B(R 2 )2, C(Ar”)3, C(R 2 )3, Si(Ar”)3, Si(R 2 )3, Ge(Ar”)3, Ge(R 2 )3, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 40 C atoms or an alkenyl group having 2 to 40 C atoms, each of which is substituted by one or more radicals R 2may be substituted, with one or more non-adjacent CH2 groups being replaced by -R 2 C=CR 2 -, -C^C-, Si(R 2 )2, Ge(R 2 )2, C=O, C=S, C=Se, C=NR 2 , -C(=O)O-, -C(=O)NR 2 -, NR 2 , P(=O)(R 2 ), -O-, -S-, SO or SO2 and where one or more Fl atoms can be replaced by D, F, CI, Br, I, CN or NO2, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each of which is substituted by one or more radicals R 2 may be substituted, or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R 2 may be substituted, or an aralkyl or heteroaralkyl group having 5 to 60 aromatic ring atoms which may be substituted with one or more radicals R 2 may be substituted, or a combination of these systems; two or more radicals R 1form a ring system, whereby one or more residues R 1 form a ring system with another part of the compound; Ar” is at each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which is substituted by one or more radicals R 2 may be substituted, whereby two radicals Ar” which bind to the same C-atom, Si-atom, N-atom, P-atom or B-atom can also be linked by a single bond or a bridge selected from B(R 2 ), C(R 2 )2, Si(R 2 )2, C=O, C=NR 2 , C=C(R 2 )2, 0, S, S=O, SO2, N(R 2 ), P(R 2 ) and P(=O)R 2 , be bridged together; R 2is selected, identically or differently at each occurrence, from the group consisting of H, D, F, CN, an aliphatic hydrocarbon radical having 1 to 20 C atoms or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, in which one or more H atoms may be replaced by D, F, CI, Br, I or CN and which may be substituted by one or more alkyl groups each having 1 to 4 carbon atoms, where two or more substituents R 2form a ring system with each other; wherein the structure of formula (I) does not comprise a six-membered ring in which a boron atom is arranged in the para-position to a nitrogen atom, and compounds with the CAS numbers CAS 1187049-34-8, CAS 1644382-05-7, CAS 1187049-50-8, CAS 1187049-48-4, CAS 1187049-54-2, CAS 1187049-57-5, CAS 1187049-56-4, CAS 1187049-46-2, CAS 1187049-52-0, CAS 941598-79-4, CAS 136638-71-6, CAS 2576721-78-1, CAS 2241934-41-6, CAS 1211481-23-0, CAS 1211481-22-9, CAS 1211481-21-8, CAS 1211481-11-6, CAS 1211481-14-9, CAS 1211481-13-8, CAS 2429897-27-6, CAS 2738960-82-0, CAS 2429897-26-5, CAS 2576721-65-6 CAS 2290579-28-9 and CAS 2429897-25-4 are exempt from protection.

2. A compound according to claim 1, comprising at least one structure of formulas (I-1) to (I-6), where the symbols X, Z, R c and R d have the meanings given in claim 1.

3. A compound according to claim 1 or 2, characterized in that the radical Ar or R represents an aromatic or heteroaromatic ring system having 5 to 13 aromatic ring atoms, which is substituted by one or more radicals R e can be substituted..

4. A compound according to one or more of claims 1 to 3, comprising at least one structure of formulas (II-1) to (II-26), where the symbols Z, R c and R d have the meanings given in claim 1 and the following applies to the other symbols used: Y e represents, the same or different at each occurrence, C(R e )2, Si(R e )2, Ge(R e )2, C=O, C=NR e , C=C(R e )2, 0, S, S=O, SO2, N(R e ), P(R e ) or P(=O)R e , where R ehas the meaning given in claim 1, or in the case that a group binds to the structure, represents N-, C(R e )-, Si(R e )- or Ge(R e )-; X e stands for N, CR, the same or different at each occurrence e or C, in the case of a group binding to the structure, with the proviso that not more than three of the groups X e in a cycle for N, where R e has the meaning given in claim 1; n is 0, 1, 2 or 3; m is 0, 1, 2, 3 or 4.

5. A compound according to one or more of claims 1 to 4, comprising at least one structure of the formulas (III-1) to (III-34), where the symbols Z, R c , R d and R e have the meanings given in claim 1 and the following applies to the other symbols used: Y e represents, the same or different at each occurrence, C(R e )2, Si(R e )2, Ge(R e )2, C=O, C=NR e , C=C(R e )2, 0, S, S=0, SO2, N(R e ), P(R e ) or P(=O)R e , where R e the one mentioned in claim 1 meaning, or in case a group binds to the structure, for N-, C(R e )-, Si(R e )- or Ge(R e )-; j is 0, 1 or 2; n is 0, 1, 2 or 3; m is 0, 1, 2, 3 or 4; I is 0, 1, 2, 3, 4 or 5.

6. A compound according to one or more of claims 1 to 5, comprising at least one structure of the formulas (IV-1) to (IV-48), where the symbols Z, R c , R d and R ehave the meanings given in claim 1 and the following applies to the other symbols used: Y e represents, the same or different at each occurrence, C(R e )2, Si(R e )2, Ge(R e )2, C=O, C=NR e , C=C(R e )2, O, S, S=O, SO2, N(R e ), P(R e ) or P(=O)R e ; n is 0, 1, 2 or 3; m is 0, 1, 2, 3 or 4; I is 0, 1, 2, 3, 4 or 5.

7. A compound according to at least one of the preceding claims, characterized in that the groups R c , R d stand for H or D.

8. A compound according to at least one of the preceding claims 1 to 6, characterized in that the groups R bonded to a C atom c or the groups R bonded to a C atom dare selected from straight-chain alkyl groups having 1 to 10 C atoms or branched or cyclic alkyl groups having 3 to 10 C atoms, each of which is substituted by one or more radicals R 1 may be substituted, preferably deuterated, wherein two or more substituents R c , R d form a ring system with each other.

9. A compound according to at least one of the preceding claims, characterized in that the group Z is C(R a ) and the group R a is selected from H, D, a straight-chain alkyl group having 1 to 10 C atoms, a branched or cyclic alkyl group having 3 to 15 C atoms, wherein the alkyl groups are each substituted by one or more radicals R 1 may be substituted or an aromatic or heteroaromatic ring system with 5 to 20 aromatic ring atoms, each substituted by one or more radicals R 1 can be substituted.

10. A compound according to at least one of the preceding claims, characterized in that the group Z represents Si(R b ) or Ge(R b ) and the group R b is selected from a straight-chain alkyl group having 1 to 10 C atoms, a branched or cyclic alkyl group having 3 to 15 C atoms, wherein the alkyl groups are each substituted by one or more radicals R 1 may be substituted or an aromatic or heteroaromatic ring system with 5 to 20 aromatic ring atoms, each substituted by one or more radicals R 1 can be substituted.

11. A compound according to at least one of the preceding claims, characterized in that the compound does not comprise a boron atom.

12. Oligomer, polymer or dendrimer containing one or more compounds according to one of claims 1 to 11, wherein instead of a hydrogen atom or a substituent, one or more bonds of the compounds to the polymer, oligomer or dendrimer are present.

13. A formulation comprising at least one compound according to one or more of claims 1 to 11 or an oligomer, polymer or dendrimer according to claim 12 and at least one further compound, wherein the further compound is selected from one or more solvents.

14. Composition containing at least one compound of formula (I) wherein the symbols used have the meanings given in claim 1, wherein the structure of formula (I) does not comprise a six-membered ring in which a boron atom is arranged in the para position to a nitrogen atom, and at least one further compound selected from the group consisting of fluorescent emitters, phosphorescent emitters, emitters exhibiting TADF, host materials, electron transport materials, electron injection materials, hole conductor materials, hole injection materials, electron blocking materials and hole blocking materials.

15. A process for preparing a compound according to one or more of claims 1 to 11, characterized in that a basic structure with an amino group is synthesized and at least one aromatic or heteroaromatic radical is introduced.

16. Use of a compound according to formula (I) wherein the symbols used have the meanings given in claim 1, wherein the structure of formula (I) does not comprise a six-membered ring in which a boron atom is arranged in the para position to a nitrogen atom, in an electronic device.

17. Electronic device containing at least one compound of formula (I) wherein the symbols used have the meanings given in claim 1, wherein the structure of formula (I) does not comprise a six-membered ring in which a boron atom is arranged in the para position to a nitrogen atom.

18. Electronic device according to claim 17, which is an organic electroluminescent device, characterized in that the compound according to formula (I) is used as host material, hole conductor material, hole injection material, electron blocking material.

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