Nitrogenous heterocycles for organic electroluminescent devices

Abstract

The present invention relates to nitrogenous heterocycles that are suitable for use in electronic devices, and to electronic devices, in particular organic electroluminescent devices, containing these heterocycles.

Description

[0001] Nitrogen-containing heterocycles for organic electroluminescent devices. The present invention relates to nitrogen-containing heterocycles for use in electronic devices, in particular in organic electroluminescent devices, as well as to electronic devices, in particular organic electroluminescent devices, containing these materials. 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 room for improvement regarding the properties of these devices, with the compounds used in the previously discussed layers having a particularly significant influence on the properties of the devices. Furthermore, phosphorescent organometallic complexes are often used as emitting materials in organic electroluminescent devices. For quantum mechanical reasons, up to four times the energy and power efficiency is possible using organometallic compounds as phosphorescence 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 solely determined by the triplet emitters used.The other materials used, such as matrix materials, are particularly important here. 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 phosphorescent emitters or emitters exhibiting TADF (thermally activated delayed fluorescence).

[0002] EP 3 070 144 A1 and WO 2017 / 178864 A1 disclose nitrogen-containing heterocycles that can be used in organic electroluminescent devices. Compounds according to the present invention are not disclosed.

[0003] In general, there is still room for improvement in these materials, for example for use as matrix materials, hole and / or electron transport materials, particularly with regard to efficiency and operating voltage, but also with regard to the lifetime of the device.

[0004] 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.

[0005] 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.

[0006] 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.

[0007] Furthermore, the compounds, especially when used as matrix materials, as hole transport materials or as electron transport materials in organic electroluminescent devices, should lead to devices that exhibit excellent lifetime and efficiency.

[0008] Another task can be seen in providing electronic devices with excellent performance as cost-effectively as possible and in consistent quality

[0009] 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.

[0010] 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.

[0011] The present invention relates to a compound comprising at least one structure of formula (I), preferably a compound according to formula (I),

[0012] where the symbols are:

[0013] A stands, identically or differently at each occurrence, for B(R), B(Ar), P(R)O, P(Ar)O, C(R)2, C(Ar)2, Si(R)2, Si(Ar)2, Ge(R)2, Ge(Ar)2, Ti(R)2, Ti(Ar)2, Zr(R)2, Zr(Ar)2, Hf(R)2, Hf(Ar)2, SO2 or SO, preferably for B(R), B(Ar), P(R)O, P(Ar)O, C(R)2, C(Ar)2, Si(R)2, Si(Ar)2, Ge(R)2 or Ge(Ar)2, particularly preferably for C(R)2, C(Ar)2, Si(R)2, Si(Ar)2, Ge(R)2 or Ge(Ar)2, and very particularly preferably for Si(Ar)2 or Si(R)2;

[0014] Z represents, the same or different at each occurrence, N(R a ), N(Ar a ), 0 or S, preferably for N(R a ) or N(Ar a ) and particularly preferred for N(Ar a );

[0015] X 1 represents N or CR, the same or different at each occurrence b , preferably for N with the proviso that not more than two of the groups X 1 , X 2 , X 3 in a cycle for N, or the group X 1 forms with a group X 2an ortho-linked aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, which is linked to one or more radicals R b can be substituted;

[0016] X 2 represents N or CR, the same or different at each occurrence b preferably for CR b provided that no more than two of the groups X 1 , X 2 , X 3 stand for N in a cycle;

[0017] X 3 represents N or CR, the same or different at each occurrence b , provided that no more than two of the groups X 1 , X 2 , X 3 in a cycle for N, or the group X 3 forms with a group X 2 an ortho-linked aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, which is linked to one or more radicals R b may be substituted, where the group X2 with a maximum of one group X 1 or X 3 forms an aromatic or heteroaromatic ring system in a cycle;

[0018] R is, at each occurrence, the same or different: H, D, OH, F, CI, Br, I, CN, NO2, N(Ar)2, N(R C )2, C(=O)N(Ar)2, C(=O)N(R c )2, C(Ar)3, C(R C )3, Si(Ar)3, Si(R c )3, Ge(R c )2, Ge(Ar)3, B(Ar)2, B(R C )2, C(=O)Ar, C(=O)R C , P(=O)(Ar)2, P(=O)(R C )2, P(Ar)2, P(R C )2, S(=O)Ar, S(=O)R C , S(=O)2Ar, S(=O)2R C , OSO2Ar, OSO2R C , 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 cmay be substituted, wherein one or more non-adjacent CH2 groups are represented by R c C=CR c , C=C, Si(R c )2, Ge(R c )2, C=O, C=S, C=Se, C=NR C , -C(=O)O-, -C(=O)NR C -, NR C , P(=O)(R C ), -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 c 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 c may be substituted, or an arylthio or heteroarylthio group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R c may be substituted, or a diarylamino, arylheteroarylamino, diheteroarylamino group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R cmay 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 c may be substituted; a radical R may be substituted with another group, preferably R b form a ring system; Ar is, identically or differently at each occurrence, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which is reacted with one or more radicals R c can be substituted, whereby two radicals Ar which bind to the same C-atom, Si-atom, Ge-atom, Ti-atom, Zr-atom, Hf-atom can also be connected by a single bond or a bridge selected from B(R c ), C(R c )2, Si(R c )2, Ge(R c )2, C=O, C=NR c , C=C(R c )2, O, S, S=O, SO2, N(R c ), P(R c ) and P(=O)R c , be bridged together; Ar ais 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 a may be substituted; R a , R b , R c is, 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 represented 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 1can be substituted; two radicals R a , R b , R c also with each other or with another group, preferably R, form a ring system; Ar' is, identically or differently at each occurrence, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which reacts with one or more radicals R 1 may be substituted, whereby two radicals Ar' which bind to the same C-atom, Si-atom, Ge-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, 0, S, S=O, SO2, N(R 1 ), P(R 1 ) and P(=O)R 1 , be bridged together;

[0019] 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, 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 2 may be substituted, with one or more non-adjacent CH2 groups being replaced by -R 2 C=CR 2 -, -C=C-, Si(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, 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 2may 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 R 1 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 linked by a single bond or a bridge selected from B(R 2 ), C(R2 )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;

[0020] R 2 is 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 2 form a ring system with each other.

[0021] Preferably, it can be provided that exactly one group X 1 , X 3 in a cycle represents N, particularly preferably the group X 1 .

[0022] 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.An electron-poor heteroaryl group within the meaning of the present invention is a heteroaryl group that has at least one heteroaromatic six-membered ring containing 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-poor heteroaryl groups are pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, quinazoline, or quinoxaline.

[0023] 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 understood as aromatic ring systems within the meaning of this invention, as are systems in which two or more aryl groups are linked, 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 by single bonds.

[0024] 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,.

[0025] 1-Butylthio, s-Butylthio, t-Butylthio, n-Pentylthio, s-Pentylthio, n-Hexylthio, Cyclohexylthio, n-Heptylthio, Cycloheptylthio, n-Octylthio, Cyclooctylthio,

[0026] 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.

[0027] 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.,

[0028] 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.

[0029] 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:

[0030] In a preferred embodiment, the compounds according to the invention can preferably comprise at least one structure of the formulas (1-1) to (1-11), and are particularly preferably selected from the compounds of the formulas (1-1) to (1-11),

[0031] where the symbols Z, A and R b have the meanings given above, in particular for formula (I) and X is N or C(R b ), preferably for C(R b ). Preferably, at most 3, particularly preferably at most two, of the groups X represent N.

[0032] Structures / compounds of the formulas (I-1) to (I-4) are preferred, structures / compounds of the formulas (I-1) and / or (I-2) are particularly preferred and structures / compounds of the formula (I-1) are very particularly preferred.

[0033] Preferably, the group Z represents N(Ar a ), whereby preferred embodiments of the group Ar awill also be explained below in connection with the group Ar, which can be part of the residue Z.

[0034] Preferably, the group A represents B(Ar), P(Ar)O, C(Ar)2, Si(Ar)2 or Ge(Ar)2, wherein preferred embodiments of the group Ar are also described below in connection with the group Ar a which may be part of the remainder A.

[0035] Preferably, it can be provided that the residue Ar, Ar a and / or R represents an aromatic or heteroaromatic ring system having 5 to 18, preferably 6 to 13 aromatic ring atoms, which is substituted by one or more radicals R a or R c can be substituted.

[0036] Furthermore, it may be provided that the group Ar and / or Ar ais selected, identically or differently at 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, anthacene, phenanthrene or triphenylene, which are each substituted with one or more radicals R c or R a may be substituted, preferably phenyl, biphenyl, fluorene, dibenzofuran, triphenylene, carbazole, indolocarbazole.

[0037] The group Ar a and / or the group Ar may preferably represent a phenyl group which is substituted with at least one radical R a or R c is substituted, wherein the substituent is in the ortho-, meta-, para-position relative to the nitrogen atom of the group N(Ar a) or the B, P, C, Si or Ge atom of group A. For example, if the radical R a or R c is a phenyl group, an ortho-, meta-, or para-biphenyl group can be formed. In the case that the group Ar a and / or the group Ar represents a triazine group, it can preferably be provided that the triazine group has two radicals R a or R c which are not equal to H or D, where the two radicals R a or R c 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.

[0038] Furthermore, the group Ar a and / or the group Ar may preferably represent a phenyl group which is substituted with at least one radical R a or R cis substituted, wherein the substituents together with the phenyl group formed by the group Ar a and / or the group Ar, 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-,

[0039] 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-,

[0040] 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 is formed.

[0041] In a further preferred embodiment, it can be provided that the group A stands for C(R)2, Si(R)2 or Ge(R)2, wherein preferred radicals R are selected from straight-chain alkyl groups having 1 to 40 C atoms or alkenyl or alkynyl groups having 2 to 40 C atoms or branched or cyclic alkyl groups having 3 to 20 C atoms, wherein this group is in each case substituted with one or more radicals R c can be substituted.

[0042] In a further embodiment, it can be provided that the structure / compound according to the present invention comprises at least one electron transport group and / or one electron-withdrawing radical. Electron transport groups are widely known in the art and promote the ability of compounds to transport and / or conduct electrons. Examples of electron transport groups are pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinazoline, quinoxaline, quinoline, isoquinoline, imidazole and / or benzimidazole groups, with triazine groups being particularly preferred. The electron-withdrawing radicals include, in particular, SO2, B(R), B(Ar), P(R)O, P(Ar)O, which can be present, for example, as group A. Furthermore, these electron-withdrawing radicals can also be present as substituent R a , R b , R c be contained in the structure / compound according to formula (I) and / or formulas (1-1) to (1-11), for example as substituents B(Ar')2, B(R1 )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 C , C(=O)R a or C(=O)R 1 .

[0043] 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.

[0044] The present compounds are particularly suitable as host materials for emitters, preferably as host materials for singlet, triplet, and TADF emitters, as electron transport materials, electron injection materials, hole conductor materials, hole injection materials, electron blocking materials, and hole blocking materials 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 and / or electron-withdrawing moieties, but no hole transport group, are particularly suitable as host materials, electron transport materials, electron injection materials, and / or hole blocking materials.Compounds that comprise one, two, or more hole-transport groups, but no electron-transport groups and / or electron-withdrawing moieties, are particularly suitable as host materials, hole-conducting materials, hole-injecting materials, and / or electron-blocking materials. Compounds that comprise one, two, or more hole-transport groups and one, two, or more electron-transport groups and / or electron-withdrawing moieties are particularly suitable as host materials.

[0045] Furthermore, it can be provided that at least one, preferably all of the radicals R, R a is / are not equal to H, preferably not equal to H, D, OH, NO2, F, CI, Br, I.

[0046] In a further preferred embodiment, it can be provided that the compounds according to the invention comprise a structure of the formulas (II-1) to (II-8), wherein the compounds according to the invention can particularly preferably be selected from the compounds of the formulas (II-1) to (II-8),

[0047] where the symbols A and R b have the meanings given above, in particular for formula (I) and the following applies to the other symbols:

[0048] X a stands for N, CR, the same or different at each occurrence a or C, in case a group binds to the structure preferably for CR a or C, provided that no more than three of the groups X a in a cycle for N, where R a has the meaning given above, in particular for formula (I);

[0049] Y represents, the same or different at each occurrence, B(R a ), C(R a )2, Si(R a )2, Ge(R a )2, C=O, C=NR a , C=C(R a )2, 0, S, S=0, S02, N(R a ), P(R a ) or P(=O)R a , preferably for N(R a ), 0, S, B(R a ), C(R a )2, Si(R a )2 or Ge(R a)2, particularly preferably for N(R a ), 0 or S, where R a has the meaning given in claim 1, or in the case that a group binds to the structure, for C(R a )-, Si(R a )-, Ge(R a )-; n is 0, 1, 2 or 3, preferably 0, 1 or 2; and m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2. Structures / compounds of the formulas (II-1), (II-2) and (II-3) are preferred, structures / compounds of the formulas (II-1) and (II-2) are particularly preferred and structures / compounds of the formula (II-1) are very particularly preferred.

[0050] In formulas (II-1 ) to (II-8) it can be provided that X a represents C if a group binds to the respective structure. This group is in particular the ring structure shown in formulas (II-2) or (II-4) provided with a radical Y. This ring structure can be linked here via a radical X. a or via Y, where in the latter case Y stands for C(R a)-, Si(R a )-, Ge(R a )- stands.

[0051] In one embodiment, it can be provided that in structures / compounds of the formulas (II-1) to (II-8) at most three, preferably two groups X a per ring for N, preferably all X a for CR a preferably at least one, particularly preferably at least two of the groups X a per ring selected from CH and CD.

[0052] Furthermore, it can be provided that at least one, preferably at least two and particularly preferably three groups X a per ring represents N, whereby these groups are preferably not adjacent. These structures / compounds preferably comprise electron transport groups and are therefore particularly suitable as electron transport materials and / or matrix materials.

[0053] 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-12), wherein the compounds according to the invention can particularly preferably be selected from the compounds of the formulas (III-1) to (III-12),

[0054] where the symbols A, R a and R b have the meanings given above, in particular for formula (I) and the following applies to the other symbols:

[0055] Y represents, the same or different at each occurrence, B(R a ), C(R a )2, Si(R a )2, Ge(R a )2, C=O, C=NR a , C=C(R a )2, 0, S, S=0, SO2, N(R a ), P(R a ) or P(=O)R a , preferably for N(R a ), 0, S, B(R a ), C(R a )2, Si(R a )2 or Ge(R a )2, particularly preferably for N(R a), 0 or S; 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;

[0056] I is 0, 1, 2, 3, 4 or 5, preferably 0, 1 or 2.

[0057] Structures / compounds of the formulas (III-1) to (III-8) are preferred, structures / compounds of the formulas (III-1), (III-2), (III-5) and (III-6) are particularly preferred and structures / compounds of the formulas (III-1) and (III-2) are very particularly preferred.

[0058] The sum of the indices j, m, n and I in structures / compounds of the formulas (II 1-1) to (III-12) is preferably at most 6, particularly preferably at most 4 and particularly preferably at most 2.

[0059] In a further 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), where the symbols R a , R b and R c have the meanings given above, in particular for formula (I), and the following applies to the further symbols: M is, identically or differently, C, Si, Ge, Ti, Zr or Hf, preferably C, Si or Ge, particularly preferably Si; Y is, identically or differently, B(R a ), C(R a )2, Si(R a )2, Ge(R a )2, C=O, C=NR a , C=C(R a )2, O, S, S=O, SO2, N(R a ), P(R a ) or P(=O)R a, preferably for N(R a ), O, S, B(R a ), C(R a )2, Si(R a )2 or Ge(R a )2, particularly preferably for N(R a ), O or S; 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;

[0060] I is 0, 1, 2, 3, 4 or 5, preferably 0, 1 or 2.

[0061] Structures / compounds of the formulas (IV-1) to (IV-8), (IV-13) to (IV-20), (IV-25), (IV-26), (IV-29), (IV-30) and (IV-38) are preferred, structures / compounds of the formulas (IV-1), (IV-2), (IV-5), (IV-6), (IV-13), (IV-14), (IV-25) and (IV-26) are particularly preferred and structures / compounds of the formulas (IV-1), (IV-2), (IV-13) and (IV-14) are very particularly preferred.

[0062] The sum of the indices j, 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.

[0063] When two residues, which can be selected in particular from R, R a , R b , R c , R 1 and / or R 2 , form a ring system with each other, this can be mono- or polycyclic, aliphatic, heteroaliphatic, aromatic or heteroaromatic. The radicals forming a ring system can be adjacent, ie these radicals are bonded to the same carbon atom or to carbon atoms that are directly bonded to each other, or they can be further apart. Furthermore, the radicals bonded to the substituents R, R a , R b , R c , R 1 and / or R 2provided ring systems can also be connected to each other via a bond, so that a ring closure can be achieved.

[0064] In a preferred development of the present invention, it can be provided that at least two, preferably adjacent radicals R, R a , R b , R c with the other groups to which the two residues R, R a , R b , R c bind, 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 13.10.2021 with the European Patent Office under the application number PCT7EP2021 / 078240, wherein for disclosure purposes the description of the condensed ring structures set out in these documents, which are formed 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

[0065] WO 2022 / 079068 A1 are incorporated into the present application by reference thereto. The ring structures described above and further described in WO 2022 / 079068 A1, which preferably comprise the ring elements of the formulas (RA-1) to (RA-12) and (RA-1a) 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 a , R b , R c , R 1 and R 2 according to the above formulas with the ring atoms of the ring system to which the substituents R a , R b , R c , 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 R2 which are attached to the substituents R a , R b , R c and R 1 may be bound.

[0067] Furthermore, it can be provided that at least one radical R a , R b , R c is 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, or the radical R a , R b , R c 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 1is 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(R1 )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 1 which 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 1identical 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 2 may 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 1which 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 1 also form a ring system with each other, which leads to a spiro system.

[0075] In the following, preferred residues R a , R b and R c described.

[0076] In a preferred embodiment of the invention, R a , R b and R c identically or differently at each occurrence selected from the group consisting of H, D, F, CN, NO2, Si(R 1 )3, B(OR 1)2, 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.

[0077] In a further preferred embodiment of the invention, radical R a , R b and R c 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.

[0078] Furthermore, it can be provided that at least one radical R a , R b and R c , preferably a substituent R a , R b and R c 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 a , R b and R cis 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 a , R b and R c either a condensed ring or the residue R a , R b and R c 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 a , R b and R c , preferably the substituent R a , R b and R cidentically 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.

[0079] Furthermore, it can be provided that at least one radical R a , R b and R c represents an aromatic or heteroaromatic ring system with 5 to 13 aromatic ring atoms, which is substituted by one or more radicals R 1 can be substituted.

[0080] Preferably, it can be provided that at least one radical, preferably a substituent R a , R b and R cis 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 1 The term substituent means in particular that R a , R b and R c are not H, preferably not H and not D. Furthermore, the substituents R a , R b and R c be the same or different if two or more substituents are present which are selected from the aromatic or heteroaromatic group mentioned.

[0081] Preferred aromatic or heteroaromatic ring systems for which substituent R, R a , R b and R cor Ar, Ar a 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 a, R c , R 1 or R 2 can be substituted.

[0082] Particularly preferred aromatic or heteroaromatic ring systems for which substituent R, R a , R b and R c or Ar, Ar a 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 a these possible substituents R 1 by R a and in the case of Ar these possible substituents are R 1 by R c to replace.

[0083] Other suitable groups R a , R b , R c are 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.

[0084] 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.

[0085] 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.

[0086] 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-spirobifluorenyl, 1- or 2-naphthyl, indole, benzofuran, benzothiophene, 1-, 2-

[0087] 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-,

[0088] 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.

[0089] In a further preferred embodiment of the invention, R 1 identically 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 2may 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 2 may 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.

[0090] In a further preferred embodiment of the invention, R 2identical 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.

[0091] 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.

[0092] In a preferred embodiment, the structures / compounds according to the invention are deuterated. The structures / compounds according to the invention preferably have a high degree of deuteration. The degree of deuteration can preferably be 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.

[0093] 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.

[0094] Accordingly, naphthyl structures are preferred over anthracene structures. Furthermore, fluorenyl, spirobifluorenyl, dibenzofuranyl, and / or dibenzothienyl structures are preferred over naphthyl structures.

[0095] Particularly preferred are structures which do not exhibit condensation, such as phenyl, biphenyl, terphenyl and / or quaterphenyl structures.

[0096] Particularly preferably, it can further be provided that the radical Ar, R does not comprise an anthracene group, preferably none of the radicals Ar, Ar a , R, R a , R b and R c , particularly preferably none of the radicals Ar, Ar a , R, R a , R b , R c , R 1 and R 2 an anthracene group.

[0097] Very particularly preferably, it can further be provided that the radicals Ar, R do not comprise an aromatic or heteroaromatic ring system which has three linearly condensed aromatic 6 rings, wherein preferably none of the radicals Ar, Ar a , R, R a , R b and R c , particularly preferably none of the radicals Ar, Ar a , R, R a , R b , R c , R 1 and R 2 an aromatic or heteroaromatic ring system which has three linearly condensed aromatic 6 rings.

[0098] If the compound according to the invention is reacted with aromatic or heteroaromatic groups R a , R b , R c , 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.

[0099] Furthermore, it can be provided that none of the residues Ar, Ar a , R, R a , R b and R c , preferentially none of the residues Ar, Ar a , R, R a , R b , R c , R 1 and R 2comprises or forms a fluorenone group. This includes substituents attached to the radicals Ar, Ar 3 , R, R a , R b , R c , etc. A fluorenone comprises a 5-membered ring with a CO group to which two aromatic 6-membered rings are fused.

[0100] 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. Furthermore, it can be provided that the compound comprises exactly two or exactly three structures according to formula (I), (I-1) to (I-11), (I-1) to (I-8), (I-1) to (I-12) and / or (IV-1) to (IV-48).

[0101] In a preferred embodiment, the compounds are selected from compounds of formula (D-1), where the group L 1represents 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 a may be substituted, and the other symbols used have the meanings given above, in particular for formula (I), where 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 Z, A.

[0102] 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 a may be substituted, but is preferably unsubstituted, where Ra may have the meaning given above, in particular for formula (I). L is particularly preferably 1 represents an aromatic ring system having 6 to 10 aromatic ring atoms or a heteroaromatic ring system having 6 to 13 heteroaromatic ring atoms, each of which is substituted 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).

[0103] Furthermore, the symbol L shown inter alia in formula (D1 ) is preferably 1identical 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.

[0104] 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.

[0105] Examples of suitable aromatic or heteroaromatic ring systems L 1are 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.

[0106] According to a preferred embodiment, a compound according to the invention can be represented by at least one of the structures according to formulas (I), (1-1) to (1-11), (11-1) to (II-8), (111-1) to (111-12) and / or (IV-1) to (IV-48). Preferably, compounds according to the invention, preferably comprising structures according to formulas (I), (1-1) to (1-11), (11-1) to (II-8), (III-1) to (III-12) and / or (IV-1) to (IV-48) 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.

[0107] Furthermore, preferred compounds according to the invention are characterized by their sublimability. These compounds generally have a molecular weight of less than approximately 1200 g / mol.

[0108] 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.

[0109] The above-mentioned preferred embodiments can be combined with each other as desired within the limitations defined in claim 1. In a particularly preferred embodiment of the invention, the above-mentioned advantages occur simultaneously.

[0110] Examples of preferred compounds according to the embodiments listed above are the compounds listed in the following table.

[0111]

[0112] The basic structure of the compounds of the invention can be prepared according to the methods outlined in the following schemes. 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.

[0113] Further information on the synthesis of the compounds according to the invention can be found in the synthesis examples.

[0114] The following schemes describe the preparation of compounds of the formula (I-1) according to the invention by way of example, so that further compounds of the invention, in particular compounds of the formulas (I-2) to (I-11), can be obtained via similar synthetic routes starting from other basic structures. Reference is made in particular to the examples in which compounds of the formulas (I-2) and (I-3) are described. The person skilled in the art will use corresponding amine compounds to prepare compounds of the formulas (I-4) to (I-11).

[0115] For example, compounds according to the invention can be prepared in three steps from building blocks known from the literature, N-benzylated 2-chloroimidazoles (1 ) and anilines (2) (Scheme 1 ).

[0116] These are first converted in step 1 to the N,N-bisbenzylated bis(2-imidazolyl)amines (3) in the presence of lithium tert-butoxide in m-xylone at 120 °C according to W. Sang et al., Adv. Synth. Catal., 2021, 363, 1408. Subsequently, according to AA Haddach et al., Tetrahedron Letters, 2002, 43, 399, the benzyl protecting groups are cleaved by the action of potassium tert-butoxide and oxygen in DMSO / THF (step 2), yielding the free bis(2-imidazolyl)amines (4). Alternatively, the cleavage can be accomplished by hydrogenolysis using reactions known to those skilled in the art, e.g., in the tetrahydrofuran / methanol / Pd-carbon / H2 system. Finally, in step 3, after deprotonation of the bis(2-imidazolyl)amines (4) with n-BuLi, coupling with the electrophiles E takes place. Dihalides such as RBCl2, R2CCl2, R2SiCl2, R2GeCl2, SiCl4, GeCl4, RP(O)Cl2, SO2Cl2, SeO2Cl2 (R = alkyl, aryl, heteroaryl) can be used as electrophiles. N-benzylated 2-chloroimidazoles and 3-chloropyrazoles, as well as 3-chlorobenzpyrazoles, can be reacted analogously. Starting from the literature-known 2,2'-oxo- or -thio-imidazoles or -benzimidazoles (6), the compounds (7) according to the invention can be obtained (Scheme 2).

[0117] 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.

[0118] A further object of the present invention is therefore a process for preparing a compound according to the invention, wherein a basic structure having an aromatic 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.

[0119] In a preferred embodiment of the process, it can be provided that the at least one aromatic or heteroaromatic radical represents an imidazole or benzimidazole compound, wherein the imidazole or benzimidazole compound is symmetrical with respect to the two nitrogen atoms.

[0120] This design can, in particular, avoid the formation of isomers, since the intermediates described above can show tautomerism.

[0121] 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).

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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).

[0126] 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.

[0127] 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 that is also used in the electronic device, for example an emitting compound and / or a further matrix material.Preferably, it can be provided that at least one further compound is 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, preferably host materials.

[0128] The present invention further relates to the use of a compound according to the invention in an electronic device, in particular in an organic electroluminescent device. Preferably, the compound according to the invention can be used in an electronic device as a host material, electron transport material, electron injection material, hole conductor material, hole injection material, electron blocking material, or hole blocking material.

[0129] Furthermore, it can be provided that a compound according to the invention is used as a host material, electron transport material, electron injection material or hole blocking material and this compound according to the invention comprises at least one electron transport group and / or one electron-withdrawing radical, wherein preferred electron transport groups and / or electron-withdrawing radicals have been defined previously.

[0130] Furthermore, it can be provided that a compound according to the invention is used as a host material, hole conductor material, hole injection material or electron blocking material and this compound according to the invention has at least one hole transport group, wherein preferred electron transport groups and / or electron-withdrawing radicals have been defined previously.

[0131] Furthermore, it can be provided that 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 and / or an electron-withdrawing radical.

[0132] The present invention further relates to an electronic device comprising at least one compound according to the invention. An electronic device within the meaning of the present invention is a device that contains at least one layer containing at least one organic compound. The component may also contain inorganic materials or layers composed entirely of inorganic materials.

[0133] 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.

[0134] 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.

[0135] 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 exhibiting TADF (thermally activated delayed fluorescence), in particular for phosphorescent emitters. Furthermore, the compound according to the invention can also be used in an electron-transport layer, electron-injection layer, and / or in a hole-transport layer, hole-injection layer, and / or in an exciton-blocking layer and / or in a hole-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 an electron-transport or hole-blocking material in an electron-transport or hole-blocking layer, or as a hole-transport or electron-blocking material in a hole-transport or electron-blocking layer. The suitability of the various compounds according to formula (I) has been explained above in connection with preferred uses.

[0136] 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).

[0137] 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.

[0138] 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.

[0139] In one embodiment of the invention, the compound according to the invention is used as the sole matrix material (“single host”) for the phosphorescent emitter.

[0140] 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.

[0141] In a preferred embodiment, a compound containing a structure / compound according to formula (I) or the preferred embodiments described above, which is used as host material, is preferably used in combination: with one or more phosphorescent materials (triplet emitters); and / or

[0142] - with one or more fluorescent materials; and / or with a compound that has TADF properties, where TADF stands for "Thermally Activated Delayed Fluorescence".

[0143] In this case, a hyperfluorescence system as described in WO 2012 / 133188 and / or a hyperphosphorescence system as described in US 2017271611 is preferably formed. This combination represents a preferred composition according to the present invention.

[0144] WO 2015 / 091716 A1 and WO 2016 / 193243 A1 disclose OLEDs containing both a phosphorescent compound and a fluorescent emitter in the emission layer, wherein the energy is transferred from the phosphorescent compound to the fluorescent emitter (hyperphosphorescence). As the skilled person knows, host materials have higher singlet and triplet energies compared to 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 have precisely such an energy relationship. The present invention also relates to electronic devices containing an organic layer, preferably a light-emitting layer, wherein the organic layer comprises:

[0145] - a compound containing a structure / compound according to formula (I) or the preferred embodiments described above as host material;

[0146] - optionally a second compound as co-host material; a sensitizer; and a fluorescent emitter, wherein the sensitizer is a phosphorescent compound (triplet emitter) or a TADF compound.

[0147] 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 hyperphosphorescence 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 2019 / 235452, wherein the compounds set out on pages 46 to 168 are preferred; in US 10,249,832, wherein the compounds set out on pages 19 to 106 are preferred; and in WO 2021 / 014001, wherein the compounds set out on pages 107 to 129 are preferred.

[0148] Likewise, another phosphorescent emitter, which emits at a shorter wavelength than the actual emitter, can be present in the mixture as a co-host material. 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 material in combination with the compound according to the invention.

[0149] Furthermore, a compound that does not participate or does not participate to a significant extent in charge transport can be used as co-host material, as described, for example, in WO 2010 / 108579.

[0150] Particularly suitable co-matrix materials in combination with the compound according to the invention are compounds that have a large band gap and do not participate, or at least not to a significant extent, in the charge transport of the emitting layer. 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.

[0151] 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 indium or platinum.

[0152] 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.

[0153] Examples of phosphorescent dopants are listed in the following table.

[0154]

[0155]

[0156] The compounds according to 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 area of ​​all pixels, even those with a color other than blue. 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, ie 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 or similar to the metal complex in the emitting layer directly adjacent to the emitting layer as a hole transport or hole injection material, as described, for example, in WO 2009 / 030981.

[0157] In the further layers of the organic electroluminescent device according to the invention, all materials commonly used in the prior art can be used. Therefore, the skilled person can, without inventive step, use all materials known for organic electroluminescent devices in combination with the compounds according to formula (I) according to the invention or the preferred embodiments described above.

[0158] Also preferred is an organic electroluminescent device, characterized in that one or more layers are coated using a sublimation process. The materials are sublimated 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.

[0159] 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.

[0160] 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.

[0161] 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.

[0162] Furthermore, hybrid processes are possible, in which, for example, one or more layers are applied from solution and one or more further layers are deposited by vapor deposition.

[0163] 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 according to the invention.

[0164] 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.

[0165] 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:

[0166] 1. Electronic devices, in particular organic electroluminescent devices containing compounds of formula (I) or the preferred embodiments described above and below, in particular as matrix material, as electron-conducting materials, or as hole-conducting materials, exhibit excellent efficiency. Compounds of the invention according to formula (I) or the preferred embodiments described above and below achieve a low operating voltage when used in electronic devices.

[0167] 2. Electronic devices, in particular organic electroluminescent devices containing compounds according to formula (I) or the preferred embodiments described above and below, in particular as matrix material, as electron-conducting materials, or as hole-conducting materials, exhibit a very long lifetime. These compounds, in particular, result in low roll-off, i.e., a low drop in the power efficiency of the device at high luminance levels.

[0168] 3. The compounds of formula (I) according to the invention or the preferred embodiments described above and below exhibit very high stability and longevity. 4. Electronic devices, in particular organic electroluminescent devices containing compounds of formula (I) or the preferred embodiments described above and below, in particular as matrix material, as electron-conducting materials, or as hole-conducting materials, exhibit a high T1 level.

[0169] 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.

[0170] 6. Compounds according to formula (I) or the preferred embodiments described above and below have excellent glass film formation.

[0171] 7. Compounds according to formula (I) or the preferred embodiments described above and below form very good films from solutions.

[0172] These advantages mentioned above are not accompanied by an excessive deterioration of the other electronic properties.

[0173] 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.

[0174] 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).

[0175] 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.

[0176] The teaching of technical action disclosed in the present invention can be abstracted and combined with other examples.

[0177] 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.

[0178] Examples:

[0179] 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.

[0180] A) Representation of synthons S Example S1 : a) Level 1 :

[0181] Procedure analogous to W. Sang et al., Adv. Synth. Catal., 2021, 363, 1408, see p. 1415, "The LiOtBu promoted reactions." Batch: 5.34 g (22 mmol) 2-chloro-1-(phenylmethyl)-1 H-benzimidazole [43181-78-8], 931 mg

[0182] (10 mmol) aniline [62-53-3], 3.20 g (40 mmol) lithium tert-butoxide [1907-33-1], 20 ml m-xylene, 30 h, 120 °C. Removal of volatile components under vacuum, chromatographic purification (Torrent column chromatography system from A. Semrau). Yield: 3.85 g (7.6 mmol) 76%; Purity: approx. 97% pure. 1 H-NMR. b) Step 1: Alternative variant

[0183] Procedure analogous to W. Sang et al., Chem. Asian J., 2020, 15, 129. Preparation: 5.34 g (22 mmol) 2-bromo-1-(phenylmethyl)-1H-benzimidazole [161885-73-0], 931 mg (10 mmol) aniline [62-53-3], 13.0 g (40 mmol) cesium carbonate, 112 mg (0.5 mmol) palladium(II) acetate, 50 ml toluene, 16 h, 110 °C. Removal of volatile components under vacuum, chromatographic purification (Torrent column machine from A.

[0184] Semrau). Yield: 4.05 g (8 mmol) 80%; Purity: approx. 97% according to 1H NMR. c) Step 2: Hydrogenolysis

[0185] Preparation: 5.06 g (10 mmol) of step 1, 2.0 g of Pd / C, dry, 10 wt. %, 5 ml of HCl, 4M in dioxane, 120 ml of MeOH, stir for 4 h under a hydrogen atmosphere at atmospheric pressure at 25 °C. Filter the catalyst through a bed of Celite, rinse with MeOH, and concentrate the filtrate. Take up the hydrochloride in dichloromethane (DCM), adjust to pH 7 with 1 N NaOH, filter off the precipitated FS with suction, separate the phases of the ML, and concentrate the DCM phase. Combine the FS and concentrated DCM phase, take up in 100 ml of MeOH, remove EtOH in vacuo (azeotrope drying), and dry the FS in vacuo. Yield: 3.03 g (9.3 mmol), 93%; Purity: approx. 97% pure. 1 H-NMR.

[0186] The following connections can be represented analogously.

[0187]

[0188] B) Preparation of the compounds according to the invention:

[0189] Example B1:

[0190] A solution of 3.25 g (10 mmol) of S1 in 100 mL of THF is treated dropwise at -78 °C with 12.5 mL (20 mmol) of n-BuLi 1.6 M in n-hexane and stirred for 30 min. A solution of 1.59 g (10 mmol) of dichlorophenylborane [873-51-8] in 30 mL of THF is then added dropwise, stirred for 1 h, and then allowed to slowly warm to room temperature. After 12 h, the THF is removed in vacuo, the residue is taken up in 50 mL of dichloromethane, and the lithium chloride is filtered off. The filtrate is concentrated to isolute and chromatographed (Torrent column system from A. Semrau). The resulting product is purified by 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: 2.91 g (7.1 mmol) 71%; Purity: approximately 99.9% by HPLC.

[0191] Analogously, the following compounds can be prepared in yields of typically 40 - 90% by adapting the respective stoichiometry to the reactants used.

[0192] Example: Production of OLEDs

[0193] 1) Vacuum-processed devices:

[0194] The production of OLEDs according to the invention and 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). The following examples present the results for 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.

[0195] 1a) Blue Fluorescence OLED Components - BF:

[0196] The compounds 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 a volume fraction of 97% and the dopant D is present in a volume fraction of 3% in the layer. 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.

[0197] 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 radiation pattern, as well as the lifetime. The EQE is specified in (%) and the voltage in (V) at a luminance of 1000 cd / m². 2 The lifetime is determined at a starting luminance of 10000 cd / m 2 The measured time during which the brightness of the reference decays to 80% of the initial brightness is set to 100%. The lifetime of the OLED components containing the compounds of the invention is expressed as a percentage of the reference.

[0198] The OLEDs have the following layer structure:

[0199] Substrat

[0200] Hole injection layer (HIL) made of HTM1 doped with 5% NDP-9 (commercially available from Novaled), 20 nm

[0201] Hole transport layer (HTL), see Table 1

[0202] Electron blocking layer (EBL), see Table 1

[0203] Emission layer (EML), see Table 1

[0204] Electron transport layer (ETL), see Table 1

[0205] Electron injection layer (EIL) made of ETM2, 1 nm

[0206] Cathode made of aluminum, 100 nm

[0207] Table 1 : Structure of blue fluorescent OLED device

[0208] Table 2: Results of blue fluorescent OLED devices

[0209] 1 b) Phosphorescent OLED components:

[0210] The compounds A according to the invention can be used in the hole injection layer (HIL), the hole transport layer (HTL), the electron blocking layer (EBL), and in the emission layer (EML) as matrix material (host material) M (see Table 5) or A (see materials according to the invention). 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 admixed 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 fabricate the OLEDs are shown in Table 5 or refer to the synthesis examples presented previously.

[0211] 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 radiation pattern, as well as the lifetime. The EQE is specified in (%) and the voltage in (V) at a luminance of 1000 cd / m². 2 The lifetime is determined at a starting luminance of 1000 cd / m 2 for blue and red and 10000 cd / m 2for green and yellow. The measured time in which the brightness of the reference decays to 80% of the initial brightness is set to 100%. The lifetime of the OLED components containing the compounds according to the invention is given as a percentage of the respective reference.

[0212] The OLEDs have the following layer structure:

[0213] Substrat

[0214] Hole injection layer (HIL) made of HTM1 doped with 5% NDP-9 (commercially available from Novaled), 20 nm

[0215] Hole transport layer (HTL), see Table 3

[0216] Electron blocking layer (EBL), see Table 3

[0217] Emission layer (EML), see Table 3

[0218] Hole blocking layer (HBL), see Table 3

[0219] Electron transport layer (ETL), made of ETM1:ETM2 (50%:50%), 30 nm

[0220] Electron injection layer (EIL) made of ETM2, 1 nm

[0221] Cathode made of aluminum, 100 nm

[0222] Table 3: Structure of phosphorescent OLED components

[0223]

[0224] Table 4: Results of phosphorescent OLED devices

[0225]

[0226] 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: In each occurrence, A represents B(R), B(Ar), P(R)O, P(Ar)O, C(R)2, C(Ar)2, Si(R)2, Si(Ar)2, Ge(R)2, Ge(Ar)2, Ti(R)2, Ti(Ar)2, Zr(R)2, Zr(Ar)2, Hf(R)2, Hf(Ar)2, SO2 or SO; Z represents, the same or different at each occurrence, N(R a ), N(Ar a ), 0 or S; X 1 represents N or CR, the same or different at each occurrence b provided that no more than two of the groups X 1 , X 2 , X 3 in a cycle for N, or the group X 1 forms with a group X 2 an ortho-linked aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, which is linked to one or more radicals R b can be substituted; X 2represents N or CR, the same or different at each occurrence b provided that no more than two of the groups X 1 , X 2 , X 3 stand for N in a cycle; X 3 represents N or CR, the same or different at each occurrence b , provided that no more than two of the groups X 1 , X 2 , X 3 in a cycle for N, or the group X 3 forms with a group X 2 an ortho-linked aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, which is linked to one or more radicals R b may be substituted, where the group X 2 with a maximum of one group X 1 or X 3 forms an aromatic or heteroaromatic ring system in a cycle; R is, at each occurrence, the same or different: H, D, OH, F, CI, Br, I, CN, NO2, N(Ar)2, N(R C)2, C(=O)N(Ar)2, C(=O)N(R c )2, C(Ar)3, C(R C )3, Si(Ar)3, Si(R c )3, Ge(R c )2, Ge(Ar)3, B(Ar)2, B(R C )2, C(=O)Ar, C(=O)R C , P(=O)(Ar)2, P(=O)(R C )2, P(Ar)2, P(R C )2, S(=O)Ar, S(=O)R C , S(=O)2Ar, S(=O)2R C , OSO2Ar, OSO2R C , 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 c may be substituted, wherein one or more non-adjacent CH2 groups are substituted by R c C=CR c , C=C, Si(R c )2, Ge(R c )2, C=O, C=S, C=Se, C=NR C , -C(=O)O-, -C(=O)NR C -, NR C , P(=O)(R C), -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 c 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 c may be substituted, or an arylthio or heteroarylthio group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R c may be substituted, or a diarylamino, arylheteroarylamino, diheteroarylamino group with 5 to 60 aromatic ring atoms, which can be substituted by one or more radicals R c 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 c substituted can be; a radical R can form a ring system with 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 c can be substituted, whereby two radicals Ar which bind to the same C atom, Si atom, Ge atom, Ti atom, Zr atom, Hf atom can also be connected by a single bond or a bridge selected from B(R C ), C(R C )2, Si(R c )2, Ge(R c )2, C=O, C=NR C , C=C(R C )2, 0, S, S=O, SO2, N(R C ), P(R C ) and P(=O)R C , be bridged together; Ar a 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 a can be substituted; R a , R b , R cis, 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 can be substituted, or a Aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which are substituted by one or more radicals R 1 can be substituted; two radicals R a , R b , R c also form a ring system with each other or with 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 with one or more radicals R 1may be substituted, whereby two radicals Ar' which bind to the same C atom, Si atom, Ge 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, 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, 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, wherein one or more non-adjacent CH2 groups are substituted by - R 2 C=CR 2 -, -CEC-, Si(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, 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 can 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 2 form a ring system with each other.

2. A compound according to claim 1, comprising at least one structure of formulas (1-1) to (1-11), where the symbols Z, A and R b have the meanings given in claim 1 and X is N or C(R b ) stands.

3. A compound according to claim 1 or 2, characterized in that Ar and / or Ar ais selected, identically or differently at 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 c or R a 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-8), where the symbols A and R b have the meanings given in claim 1 and the following applies to the other symbols used: Y represents, the same or different at each occurrence, B(R a ), C(R a )2, Si(R a )2, Ge(R a )2, C=O, C=NR a , C=C(Ra )2, 0, S, S=0, SO2, N(R a ), P(R a ) or P(=O)R a , where R a has the meaning given in claim 1, or in the case that a group binds to the structure, for C(R a )-, Si(R a )-, Ge(R a )-; X a stands for N, CR, the same or different at each occurrence a or C, in the case of a group binding to the structure, with the proviso that not more than three of the groups X a in a cycle for N, where R a 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-12), where the symbols A, R a and R bhave the meanings given in claim 1 and the following applies to the other symbols used: Y represents, the same or different at each occurrence, B(R a ), C(R a )2, Si(R a )2, Ge(R a )2, C=O, C=NR a , C=C(R a )2, 0, S, S=0, SO2, N(R a ), P(R a ) or P(=O)R a , 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 R a , R b and R chave the meanings given in claim 1 and the following applies to the other symbols used: M, the same or different at each occurrence, represents C, Si, Ge, Ti, Zr or Hf; Y represents, the same or different at each occurrence, B(R a ), C(R a )2, Si(R a )2, Ge(R a )2, C=O, C=NR a , C=C(R a )2, 0, S, S=O, SO2, N(R a ), P(R a ) or P(=O)R a ; 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.

7. A compound according to one or more of claims 1 to 6, characterized in that at least one radical R a , R b , R c is selected, identically or differently at 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 a aromatic or heteroaromatic ring system selected from the groups of the following formulas Ar-1 to Ar-76, or the radical R a , R b , R c 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 where R 1 has the meanings given above, the dashed bond represents the bond to the corresponding group and furthermore: Ar 1 is at each occurrence, identically or differently, a bivalent aromatic or heteroaromatic ring system with 6 to 18 aromatic ring atoms, each of which is linked to one or more radicals R 1 can be substituted; 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 the corresponding carbon atoms are bonded instead to residues R 1 are bound.

8. A compound according to at least one of the preceding claims, characterized in that the compound comprises at least one electron transport group and / or one electron withdrawing radical.

9. A compound according to at least one of the preceding claims, characterized in that the compound comprises at least one hole transport group.

10. Oligomer, polymer or dendrimer containing one or more compounds according to any one of claims 1 to 9, wherein instead of a hydrogen atom or a substituent, one or more bonds of the compounds to the polymer, oligomer or dendrimer are present.

11. A formulation comprising at least one compound according to one or more of claims 1 to 9 or an oligomer, polymer or dendrimer according to claim 10 and at least one further compound, wherein the further compound is selected from one or more solvents.

12. A composition comprising at least one compound according to one or more of claims 1 to 9 or an oligomer, polymer or dendrimer according to claim 10 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.

13. A process for preparing a compound according to one or more of claims 1 to 9, characterized in that a basic structure with an aromatic amino group is synthesized and at least one aromatic or heteroaromatic radical is introduced.

14. Use of a compound according to one or more of claims 1 to 9 or an oligomer, polymer or dendrimer according to claim 10 in an electronic device.

15. An electronic device comprising at least one compound according to one or more of claims 1 to 9 or an oligomer, polymer or dendrimer according to claim 10.

16. Electronic device according to claim 15, which is an organic electroluminescent device, characterized in that the compound according to one or more of claims 1 to 9 or the oligomer, polymer or dendrimer according to claim 10 is used as host material, electron transport material, electron injection material, hole conductor material, hole injection material, electron blocking material, hole blocking material.

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