EP4244228A1

EP4244228A1 - Sulfurous compounds for organic electroluminescent devices

Info

Publication number: EP4244228A1
Application number: EP21805960.8A
Authority: EP
Inventors: Amir Hossain Parham; Christian Ehrenreich
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2020-11-10
Filing date: 2021-11-09
Publication date: 2023-09-20
Also published as: US20230422610A1; WO2022101171A1; CN116601157A; KR20230107308A

Abstract

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

Description

Sulfur-containing compounds for organic electroluminescent devices The present invention relates to sulfur-containing compounds for use in electronic devices, in particular in organic electroluminescent devices, and electronic devices, in particular organic electroluminescent devices, containing these materials. In organic electroluminescence devices, phosphorescent organometallic complexes are frequently used as emitting materials. For quantum mechanical reasons, up to four times the energy and power efficiency is possible when using organometallic compounds as phosphorescence emitters. In general, there is still a need for improvement in the case of electroluminescent devices, in particular also in the case of electroluminescent devices which exhibit triplet emission (phosphorescence). The properties of phosphorescent electroluminescent devices are not only determined by the triplet emitters used. The other materials used, such as matrix materials, are also of particular importance here. Improvements in these materials can therefore also lead to significant improvements in the properties of the electroluminescent devices. WO 2019/022435 discloses thionylcarbazole derivatives as matrix materials for phosphorescent emitters. Furthermore, US Pat. No. 10/312455 B2 discloses compounds which are suitable as TADF (thermally activated delayed fluorescence) emitters. Furthermore, US 2019/100543 A1 discloses complexes which comprise thionylcarbazole structural elements. In general, there is still a need for improvement with these materials, for example for use as matrix materials, in particular with regard to the service life, but also with regard to the efficiency and the operating voltage of the device. 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 lead to good device properties when used in this device, and to provide the corresponding electronic device . In particular, it is the object of the present invention to provide connections that lead to a long service life, good efficiency and low operating voltage. The properties of the matrix materials in particular also have a significant influence on the service life and the efficiency of the organic electroluminescent device. A further object of the present invention can be seen as providing compounds which are suitable for use in a phosphorescent or fluorescent electroluminescent device, in particular as a matrix material. In particular, it is an object of the present invention to provide matrix materials which are suitable for red and yellow phosphorescent electroluminescent devices, in particular for red phosphorescent electroluminescent devices and optionally also for blue phosphorescent electroluminescent devices. Furthermore, the compounds should lead to devices which have excellent color purity, particularly when they are used as matrix materials, as hole-transport materials or as electron-blocking materials in organic electroluminescent devices. A further object can be seen in providing electronic devices with excellent performance as cost-effectively as possible and with constant quality. Furthermore, the electronic devices should be able to be used or adapted for many purposes. In particular, the Performance of the electronic devices are maintained over a wide temperature range. It has surprisingly been found that certain compounds described in more detail below solve this problem, are well suited for use in electroluminescent devices and lead to improvements in the organic electroluminescent device, in particular in relation to the service life, the color purity, the efficiency and the operating voltage. These compounds and electronic devices, in particular organic electroluminescent devices, which contain such compounds are therefore the subject matter of the present invention. The present invention relates to a compound comprising at least one structure of the formula (1), preferably a compound of the formula (1), where the following applies to the symbols and indices used: T stands for a heteroaromatic 5-membered ring with a sulfur atom which is fused to the azole ring via two adjacent and interconnected carbon atoms and which can be substituted by one or more groups R ³ ; L represents a linking group, preferably selected from a bond or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can be substituted with one or more radicals R ² , particularly preferably a bond; X is N, CR or C if a group L, Y ¹ or Y ² is attached thereto, with the proviso that no more than two of the groups X in a cycle are N, preferably X is C or CR; X ¹ is N, CR ¹ or C if the group L is attached thereto, with the proviso that no more than two of the groups X in a cycle are N, preferably X ¹ is CR ¹ ; Y represents NAr, NL, O, S, C(R ² )2, C(L)(R ² ), where NL means that the group L binds to the nitrogen atom of the group NL, and C(L)(R ² ) means that the group L binds to the C atom of the group C(L)(R ² ); Y ¹ represents a bond, NL, NR ² , NAr', O, S, C(R ² )2, where NL means that the group L binds to the nitrogen atom of the group NL; r is 0 or 1, where r=0 means that the group Y ¹ is absent; Y ² represents a bond, NL, NR ² , NAr', O, S, C(R ² )2, where NL means that the group L binds to the nitrogen atom of the group NL; s is 0 or 1, where s=0 means that the group Y ² is absent; Ar is identical or different on each occurrence, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can be substituted with one or more R ² radicals; R is the same or different on each occurrence H, D, F, Cl, Br, I, N(R ⁴ )2, N(Ar')2, CN, NO2, OR ⁴ , SR ⁴ , COOR ⁴ , C(= O)N(R4 ) ² , Si(R4 ) ³ , B(OR4 ) ² , C(=O)R4 , P(=O)( ^R4 ) ² , S(=O) ^R4 , S(=O)2R ⁴ , OSO2R ⁴ , a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, the Alkyl, alkenyl or alkynyl group can each be substituted with one or more radicals R ⁴ and where one or more non-adjacent CH 2 groups are replaced by Si(R ⁴ ) 2 , C═O, NR ⁴ , O, S or CONR ⁴ can be, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, preferably with 5 to 40 aromatic ring atoms, which can each be substituted by one or more radicals R ⁴ ; two radicals R or one radical R with one radical R ² , R ³ can also form an aliphatic or heteroaliphatic ring system with one another, the radicals R preferably not forming such a ring system; R ¹ is identical or different on each occurrence H, D, F, Cl, Br, I, N(R ⁴ )2, N(Ar')2, CN, NO2, OR ⁴ , SR ⁴ , COOR ⁴ , C( =O)N(R4 ) ² , Si(R4 ) ³ , B(OR4 ) ² , C(=O)R4 , P(=O)( ^R4 ) ² , S(=O) ^R4 , S(=O)2R ⁴ , OSO2R ⁴ , a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group can each be substituted with one or more radicals R ⁴ and one or more non-adjacent CH2 groups can be replaced by Si(R ⁴ )2, C=O, NR ⁴ , O, S or CONR ⁴ can be replaced, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, preferably with 5 to 40 aromatic ring atoms, which can each be substituted by one or more radicals R ⁴ ; two radicals R ¹ or one radical R ¹ with one radical R ² can also form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system with one another, the radicals R ¹ preferably not forming such a ring system; R ² is the same or different on each occurrence, H, D, F, Cl, Br, I, N(R ⁴ )2, N(Ar')2, CN, NO2, OR ⁴ , SR ⁴ , COOR ⁴ , C( =O)N(R4 ) ² , Si(R4 ) ³ , B(OR4 ) ² , C(=O)R4 , P(=O)( ^R4 ) ² , S(=O) ^R4 , S(=O)2R ⁴ , OSO2R ⁴ , a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group can each be substituted with one or more radicals R ⁴ and one or more non-adjacent CH2 groups can be replaced by Si(R ⁴ )2, C=O, NR ⁴ , O, S or CONR ⁴ can be replaced, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, preferably with 5 to 40 aromatic ring atoms, which can each be substituted by one or more radicals R ⁴ ; two radicals R ² or one radical R ² with one radical R, R ¹ , R ³ can also form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system with one another, the radicals R ² preferably not forming such a ring system; R ³ is identical or different on each occurrence H, D, F, Cl, Br, I, N(R ⁴ )2, N(Ar')2, CN, NO2, OR ⁴ , SR ⁴ , COOR ⁴ , C( =O)N(R4 ) ² , Si(R4 ) ³ , B(OR4 ) ² , C(=O)R4 , P(=O)( ^R4 ) ² , S(=O) ^R4 , S(=O)2R ⁴ , OSO2R ⁴ , a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group can each be substituted with one or more radicals R ⁴ and one or more non-adjacent CH2 groups can be replaced by Si(R ⁴ )2, C=O, NR ⁴ , O, S or CONR ⁴ can be replaced, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, preferably with 5 to 40 aromatic ring atoms, which can each be substituted by one or more radicals R ⁴ ; two radicals R ³ or one radical R ³ with one radical R, R ² can also form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system with one another, the radicals R ³ preferably not forming such a ring system; Ar' is identical or different on each occurrence, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can be substituted with one or more R ⁴ radicals; R ⁴ is the same or different on each occurrence: H, D, F, Cl, Br, I, N(R ⁵ )2, CN, NO2, OR ⁵ , SR ⁵ , Si(R ⁵ )3, B(OR ⁵ ) 2, C(=O)R ⁵ , P(=O)(R ⁵ )2, S(=O)R ⁵ , S(=O)2R ⁵ , OSO2R ⁵ , a straight-chain alkyl group with 1 to 20 C -Atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group is substituted with one or more radicals R ⁵ can be tuated, where one or more non-adjacent CH2 groups can be replaced by Si(R ⁵ )2, C═O, NR ⁵ , O, S or CONR ⁵ , or an aromatic or heteroaromatic ring system with 5 to 40 aromatic ring atoms, each of which may be substituted by one or more R ⁵ radicals; two or more radicals R ⁴ together can form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system, preferably the radicals R ⁴ do not form such a ring system; R ⁵ is identical or different on each occurrence and is H, D, F or an aliphatic, aromatic or heteroaromatic organic radical, in particular a hydrocarbon radical, having 1 to 20 carbon atoms, in which one or more H atoms can also be replaced by F ; where the sum of r and s is 1 or 2, preferably 1. An aryl group within the meaning of this invention contains 6 to 40 carbon atoms; a heteroaryl group within the meaning of this invention contains 2 to 40 carbon atoms and at least one heteroatom, with the proviso that the sum of carbon 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 either a simple aromatic cycle, ie benzene, or a simple heteroaromatic cycle, e.g. pyridine, pyrimidine, thiophene, etc., or a fused (fused) aryl or heteroaryl group, e.g. naphthalene, anthracene, phenanthrene, quinoline, isoquinoline, etc. On the other hand, aromatics linked to one another by a single bond, such as biphenyl, are not referred to as aryl or heteroaryl groups, but as aromatic ring systems. An electron-deficient heteroaryl group in the context of the present invention is a heteroaryl group which has at least one heteroaromatic six-membered ring with at least one nitrogen atom. Further aromatic or heteroaromatic five-membered rings or six-membered rings can be fused onto this six-membered ring. Examples of electron-deficient heteroaryl groups are pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, quinazoline or quinoxaline. An aromatic ring system within the meaning of this invention contains 6 to 60 carbon atoms in the ring system. A heteroaromatic ring system within the meaning of this invention contains 2 to 60 carbon atoms and at least one heteroatom in the ring system, with the proviso that the sum of carbon atoms and heteroatoms is at least 5. The heteroatoms are preferably selected from N, O and/or S. An aromatic or heteroaromatic ring system in the context of this invention is to be understood as meaning a system which does not necessarily only contain aryl or heteroaryl groups, but in which also several aryl or heteroaryl groups by a non-aromatic moiety, such as. B. a C, N or O atom may be connected. For example, systems such as fluorene, 9,9'-spirobifluorene, 9,9-diarylfluorene, triarylamine, diaryl ether, stilbene, etc. should also be understood as aromatic ring systems for the purposes of this invention, and also systems in which two or more Aryl groups are connected, for example, by a short alkyl group. The aromatic ring system is preferably selected from fluorene, 9,9'-spirobifluorene, 9,9-diarylamine or groups in which two or more aryl and/or heteroaryl groups are linked to one another by single bonds. In the context of the present invention, an aliphatic hydrocarbon radical or an alkyl group or an alkenyl or Alkynyl group which can contain 1 to 20 carbon atoms and in which individual H atoms or CH2 groups can also be substituted by the groups mentioned above, 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, Pentynyl, hexynyl, heptynyl or octynyl understood. An alkoxy group having 1 to 40 carbon atoms is preferably methoxy, trifluoromethoxy, 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, cyclooctyloxy, 2-ethylhexyloxy, pentafluoroethoxy and 2,2,2-trifluoroethoxy. A thioalkyl group with 1 to 40 carbon atoms is, in particular, methylthio, ethylthio, n-propylthio, i-propylthio, n-butylthio, i-butylthio, s-butylthio, t-butylthio, n-pentylthio, s-pentylthio, n-hexylthio, cyclohexylthio, n-heptylthio, cycloheptylthio, n-octylthio, cyclooctylthio, 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, according to the present invention, alkyl, alkoxy or thioalkyl groups can be straight-chain, branched or cyclic, it being possible for one or more non-adjacent CH2 groups to be replaced by the groups mentioned above; furthermore, one or more H atoms can also be replaced by D, F, Cl, Br, I, CN or NO2, preferably F, Cl or CN, more preferably F or CN, particularly preferably CN. An aromatic or heteroaromatic ring system with 5-60 or 5 to 40 aromatic ring atoms, which can be substituted with the above-mentioned radicals and which can be linked via any position on the aromatic or heteroaromatic, 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, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, pyridine, quinoline, isoquinoline, acridine, phenanthridine, benzo-5,6-quinoline, benzo-6,7 -quinoline, benzo-7,8-quinoline, phenothiazine, phenoxazine, pyrazole, indazole, imidazole, benzimidazole, naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazineimidazole, quinoxalineimidazole, oxazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, 1,2 -Thiazole, 1,3-thiazole, benzothiazole, pyridazine, hexaazatriphenylene, benzopyridazine, pyrimidine, benzopyrimidine, quinoxaline, 1,5-diazaanthracene, 2,7-diazapyrene, 2,3-diazapyrene, 1,6 -diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene, 4,5,9,10-tetra- azaperylene, pyrazine, phenazine, phenoxazine, phenothiazine, fluororubine, naphthyridine, azacarbazole, benzocarboline, phenanthroline, 1,2,3-triazole, 1,2,4-triazole, benzotriazole, 1,2,3-oxadiazole, 1,2, 4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1, 3,4-thiadiazole, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, tetrazole, 1,2,4,5-tetrazine, 1,2,3,4- tetrazine, 1,2,3,5-tetrazine, purine, pteridine, indolizine and benzothiadiazole or groups derived from combinations of these systems. In the context of the present description, the wording that two or more radicals can form a ring with one another is to be understood, inter alia, as meaning that the two radicals are linked to one another by a chemical bond with formal splitting off of two hydrogen atoms. This is illustrated by the following scheme. Furthermore, the above formulation should also be understood to mean that if one of the two radicals is hydrogen, the second radical is attached to the position, forming a ring, to which the hydrogen atom was bonded. This should be illustrated by the following scheme: In a preferred embodiment, the compounds according to the invention can preferably have at least one structure of the formulas (1a), (1b), (1c), (1d), (1e), (1f), (1g), (1h), (1i), (1j), (1k), (1l), (1m), (1n), (1o), (1p), (1q), (1r), (1s), (1t), (1u), (1v ), (1w), (1x), (1y), (1z) and (1za) and are particularly preferably selected from the compounds of the formulas (1a), (1b), (1c), (1d), (1e ), (1f), (1g), (1h), (1i), (1j), (1k), (1l), (1m), (1n), (1o), (1p), (1q), (1r), (1s), (1t), (1u), (1v), (1w), (1x), (1y), (1z) and (1za),

where the symbols Y, Y ¹ , Y ² , X, X ¹ , r, s and R ³ have the meanings given above, in particular for formula (1), j is 0, 1 or 2, preferably 0 or 1 and k is 0 or 1, where s + k = 0 or 1 and j + s = 0, 1 or 2. With regard to the formulas (1a), (1b), (1c), (1d), (1e), (1f), (1g), (1h), (1i), (1j), (1k) set out above , (1l), (1m), (1n), (1o), (1p), (1q), (1r), (1s), (1t), (1u), (1v), (1w), ( 1x), (1y), (1z) and (1za) it should be noted that these are partly similar, but at least partly differ in the connection points of the connection group L. Thus, the linking group L in formulas (1a), (1b), (1c) can attach to any suitable attachment site of the two structural groups linked by the linking group L. In formulas (1d), (1e), (1f), the linking group L binds to the thiofuran ring and in formulas (1g), (1h), (1i) does not bind to the thiofuran ring. In formulas (1j), (1k), (1l) the linking group L binds to an aromatic or heteroaromatic moiety of the fluorene, dibenzofuran, dibenzothiofuran or carbazole group, the linking group L binding to any suitable attachment site of the bridged thionylcarbazole moiety can. The other structures result from these differences accordingly. It can preferably be provided that in compounds of the formulas (1), (1a), (1b), (1c), (1d), (1e), (1f), (1g), (1h), (1i), (1j), (1k), (1l), (1m), (1n), (1o), (1p), (1q), (1r), (1s), (1t), (1u), (1v ), (1w), (1x), (1y), (1z) and (1za) not more than four, preferably not more than two groups X are N, particularly preferably all groups X are CR or C, with preferably at most 4, particularly preferably at most 3 and especially preferably at most 2 of the groups CR for which X stands, is not equal to the group CH. Furthermore, it can be provided that in compounds of the formulas (1), (1a), (1b), (1c), (1d), (1e), (1f), (1g), (1h), (1i), (1j), (1k), (1l), (1m), (1n), (1o), (1p), (1q), (1r), (1s), (1t), (1u), (1v ), (1w), (1x), (1y), (1z) and (1za) not more than four, preferably not more than one group X ¹ is N, more preferably all groups X ¹ are CR ¹ or C, where preferably at most 3 and particularly preferably at most 2 of the groups CR for which X ¹ stands are different from the group CH. In a further embodiment it can be provided that in compounds of the formulas (1), (1a), (1b), (1c), (1d), (1e), (1f), (1g), (1h), ( 1i), (1j), (1k), (1l), (1m), (1n), (1o), (1p), (1q), (1r), (1s), (1t), (1u) , (1v), (1w), (1x), (1y), (1z) and (1za) the index r = 1 and the index s = 0 such that the group Y ¹ is present and the group Y ² is not is available. In a further preferred embodiment it can be provided that the compounds according to the invention have a structure of the formulas (2a), (2b), (2c), (2d), (2e), (2f), (2g), (2h), ( 2i), (2j), (2k), (2l), (2m), (2n), (2o), (2p), (2q), (2r), (2s), (2t), (2u) , (2v), (2w), (2x), (2y), (2z) and (2za), where the compounds according to the invention can be particularly preferably selected from the compounds of the formulas (2a), (2b), (2c). ), (2d), (2e), (2f), (2g), (2h), (2i), (2j), (2k), (2l), (2m), (2n), (2o), (2p), (2q), (2r), (2s), (2t), (2u), (2v), (2w), (2x), (2y), (2z) and (2za),

where L, Y, R, R ¹ and R ³ have the meanings mentioned above, in particular for formula (1), the index k is 0 or 1, the index j is 0, 1 or 2, preferably 0 or 1, the index n is 0, 1, 2 or 3, preferably 0, 1 or 2 and more preferably 0 or 1 and the index m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2 and most preferably 0 or 1. With regard to the formulas (2a), (2b), (2c), (2d), (2e), (2f), (2g), (2h), (2i), (2j), (2k) set out above , (2l), (2m), (2n), (2o), (2p), (2q), (2r), (2s), (2t), (2u), (2v), (2w), ( 2x), (2y), (2z) and (2za) it should be noted that these are partly similar, but at least partly differ in the connection points of the connection group L. Thus, the linking group L in formulas (2a), (2b), (2c) can be attached to any suitable attachment site of the two linked by the linking group L bind structure groups. In formulas (2d), (2e), (2f), the linking group L binds to the thiofuran ring and in formulas (2g), (2h), (2i) does not bind to the thiofuran ring. In formulas (2j), (2k), (2l), the linking group L binds to an aromatic moiety of the fluorene, dibenzofuran, dibenzothiofuran or carbazole group, where the linking group L can bind to any suitable attachment site of the bridged thionylcarbazole moiety. The other structures result from these differences accordingly. In a preferred embodiment it can be provided that in compounds of the formulas (1), (1a), (1b), (1c), (1d), (1e), (1f), (1g), (1h), ( 1i), (1j), (1k), (1l), (1m), (1n), (1o), (1p), (1q), (1r), (1s), (1t), (1u) , (1v), (1w), (1x), (1y), (1z) and (1za) the index s = 1 and the index r = 0 such that the group Y ² is present and the group Y ¹ is not is available. In a further preferred embodiment it can be provided that the compounds according to the invention have a structure of the formulas (3a), (3b), (3c), (3d), (3e), (3f), (3g), (3h), ( 3i), (3j), (3k), (3l), (3m), (3n), (3o), (3p), (3q) and (3r), it being possible for the compounds according to the invention to be selected particularly preferably from the compounds of the formulas (3a), (3b), (3c), (3d), (3e), (3f), (3g), (3h), (3i), (3j), (3k), (3l ), (3m), (3n), (3o), (3p), (3q) and (3r), where L, Y, R, R ¹ and R ³ have the meanings mentioned above, in particular for formula (1), the index k is 0 or 1, the index n is 0, 1, 2 or 3, preferably 0, 1 or 2 and more preferably 0 or 1 and the index m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2 and most preferably 0 or 1. With regard to the formulas (3a), (3b), (3c), (3d), (3e), (3f), (3g), (3h), (3i), (3j), (3k) set out above , (3l), (3m), (3n), (3o), (3p), (3q) and (3r) it should be noted that these are partly similar, but at least partly differ in the connection points of the connection group L. Thus, the linking group L in formulas (3a), (3b) can attach to any suitable attachment site of the two structural groups linked by the linking group L. In the formulas (3c), (3d), the linking group L binds to the thiofuran ring and in the formulas (3e), (3f) does not bind to the thiofuran ring. In formulas (3g), (3h) the linking group L binds to an aromatic moiety of the fluorene, dibenzofuran, dibenzothiofuran or carbazole group, where the linking group L can bind to any suitable attachment site of the bridged thionylcarbazole moiety. The other structures result from these differences accordingly. In a further preferred embodiment it can be provided that the compounds according to the invention have a structure of the formulas (4a), (4b), (4c), (4d), (4e), (4f), (4g), (4h), ( 4i), (4j), (4k), (4l), (4m), (4n), (4o), (4p), (4q) and (4r), it being possible for the compounds according to the invention to be selected particularly preferably from the connections of Formulas (4a), (4b), (4c), (4d), (4e), (4f), (4g), (4h), (4i), (4j), (4k), (4l), ( 4m), (4n), (4o), (4p), (4q) and (4r),

where L, Y, R, R ¹ and R ³ have the meanings mentioned above, in particular for formula (1), the index k is 0 or 1, the index j is 0, 1 or 2, preferably 0 or 1, the index n is 0, 1, 2 or 3, preferably 0, 1 or 2 and more preferably 0 or 1 and the index m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2 and most preferably 0 or 1. In a preferred embodiment of the present invention it can be provided that the compound has at least one structure of the formulas (5a), (5b), (5c), (5d), (5e), (5f), (5g), (5h) and (5i), where particularly preferably a compound is selected from the compounds of the formulas (5a), (5b), (5c), (5d), (5e), (5f), (5g), (5h ) and (5i),

where L, Y, R, R ¹ and R ³ have the meanings mentioned above, in particular for formula (1), the index k is 0 or 1, the index j is 0, 1 or 2, preferably 0 or 1, the index n is 0, 1, 2 or 3, preferably 0, 1 or 2 and more preferably 0 or 1 and the index m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2 and most preferably 0 or 1. With regard to the formulas (5a), (5b), (5c), (5d), (5e), (5f), (5g), (5h) and (5i) presented above, it should be noted that some of these are similar , but at least partially differ in the connection points of the connection group L. Thus, the linking group L in formulas (5a), (5b), (5c) can attach to any suitable attachment site of the thionylcarbazole moiety. In formulas ((5d), (5e), (5f) the linking group L binds to the thiofuran ring and in formulas (5g), (5h) and (5i) does not bind to the thiofuran ring. In a preferred embodiment of the invention, the Compounds preferably at least one structure of the formulas (6a), (6b), (6c), (6d), (6e), (6f), (6g) and (6h), where the compounds are particularly preferably selected from the Compounds of formulas (6a), (6b), (6c), (6d), (6e), (6f), (6g) and (6h), where L, Y, R, R ¹ and R ³ have the meanings mentioned above, in particular for formula (1), the index k is 0 or 1, the index j is 0, 1 or 2, preferably 0 or 1, the index n is 0, 1, 2 or 3, preferably 0, 1 or 2 and more preferably 0 or 1 and the index m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2 and most preferably 0 or 1. The sum of the indices k, j, m and n in structures/compounds of formulas (2a) to (2za), (3a) to (3r), (4a) to (4r), (5a) to (5i) and ( 6a) to (6h) is preferably at most 6, particularly preferably at most 4 and particularly preferably at most 2. The group L represents a linking group, which is preferably selected from a bond, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms which may be substituted with one or more R ² radicals, or an N-containing group, preferably a mono -, di- or triarylamine group. In a preferred embodiment, the linking group L is particularly preferably selected from a bond or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can be substituted by one or more R ² radicals, L particularly preferably being a bond. In a further embodiment, the group L is a radical which links the two structural elements via a nitrogen-containing group, in particular via a mono-, di- or triarylamine group. For example, the group L may represent a group of the formula -N(Ar ^a )-, -N(Ar ^a )-Ar ^b - or -Ar ^c -N(Ar ^a )-Ar ^b - where Ar ^a , Ar ^b and Ar ^c are identical or different on each occurrence and are an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms, which can each be substituted by one or more R ² radicals. The total number of aromatic ring atoms of Ar ^a , Ar ^b and Ar ^c is at most 60 and preferably at most 40. Ar ^c and Ar ^a can be connected to one another and/or Ar ^a and Ar ^b can also be connected to one another by a group selected from C(R ² )2, NR ² , O or S can be connected. Ar ^c and Ar ^a are preferably linked to one another or Ar ^a and Ar ^b are linked to one another in each case ortho to the position of the linkage to the nitrogen atom. In a further embodiment of the invention, none of the groups Ar ^a , Ar ^b or Ar ^c are connected to one another. Ar ^c is preferably an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, preferably having 6 to 12 aromatic ring atoms, which can each be substituted by one or more R ² radicals. Ar ^c is particularly preferably selected from the group consisting of ortho-, meta- or para-phenylene or ortho-, meta- or para-biphenyl, each of which may be substituted by one or more R ⁴ radicals, but is preferably unsubstituted. Most preferably, Ar ^c is an unsubstituted phenylene group. Ar ^a and Ar ^b are preferably identical or different on each occurrence and are an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, which can each be substituted by one or more R ² radicals. Particularly preferred groups Ar ^a or Ar ^b are identical or different on 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 -, 3- or 4-carbazole, 1-, 2-, 3- or 4-dibenzofuran, 1-, 2-, 3- or 4-dibenzothiophene, indenocarbazole, indolocarbazole, 2-, 3- or 4-pyridine, 2 -, 4- or 5-pyrimidine, pyrazine, pyridazine, triazine, phenanthrene or triphenylene, each of which may be substituted by one or more R ² radicals. Ar ^a and Ar ^b are very particularly preferably identical or different 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 ver- 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 . The group L can preferably form a continuous conjugation with the groups to which the group L according to formula (1) or the preferred embodiments of this formula is bonded. Continuous conjugation of the aromatic or heteroaromatic systems is formed as soon as direct bonds are formed between adjacent aromatic or heteroaromatic rings. A further linkage between the aforementioned conjugated groups, which takes place for example via an S, N or O atom or a carbonyl group, does not damage a conjugation. In a fluorene system, the two aromatic rings are bonded directly, with the sp ³ hybridized carbon atom in position 9 preventing a condensation of these rings, but a Conjugation can take place since this sp ³ hybridized carbon atom in position 9 does not necessarily lie between the groups which are connected via the linking group L. In contrast, in a second spirobifluorene structure, continuous conjugation can be formed if the linkage between the groups linked through the linking group L is through the same phenyl group of the spirobifluorene structure or through phenyl groups of the spirobifluorene structure that are bonded directly to each other and in a plane lying, takes place. If the linkage between the groups linked through linking group L is through different phenyl groups of the second spirobifluorene structure linked through the sp ³ hybridized carbon atom at position 9, the conjugation is disrupted. In a further preferred embodiment of the invention, L represents a bond or 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 can be substituted by one or more R ² radicals, but is preferably unsubstituted, where R ² can have the meaning given above, in particular for formula (1). L particularly preferably represents a bond or 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 may be substituted by one or more R ² radicals, but is preferably unsubstituted, where R ² can have the meaning mentioned above, in particular for formula (1). Furthermore, the symbol L set out in formula (1), among other things, is the same 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. Furthermore, it can be provided that the group L set out in formula (1) comprises an aromatic ring system with at most two fused aromatic and/or heteroaromatic 6-rings, preferably no fused aromatic or heteroaromatic ring system. Accordingly, naphthyl structures are preferred over anthracene structures. Furthermore, fluorenyl, spirobifluorenyl, dibenzofuranyl and/or dibenzothienyl structures are preferred over naphthyl structures. Particularly preferred are structures that do not exhibit condensation, such as phenyl, biphenyl, terphenyl and/or quaterphenyl structures. Examples of suitable aromatic or heteroaromatic ring systems L are selected from the group consisting of ortho-, meta- or para-phenylene, ortho-, meta- or para-biphenylene, terphenylene, in particular branched terphenylene, quaterphenylene, in particular branched quaterphenylene, fluorenylene, spirobifluorenylene , Dibenzofuranylene, dibenzothienylene and carbazolylene, each of which may be substituted by one or more radicals R ² , but are preferably unsubstituted. Furthermore, it can be provided that the group L set out in formula (1), inter alia, has at most 1 nitrogen atom, preferably at most 2 heteroatoms, particularly preferably at most one heteroatom and particularly preferably no heteroatom. Furthermore, it can be provided that the group L does not form a fused aromatic or heteroaromatic ring system with the groups to which the group L binds, this including the radicals R, R ¹ , R ² or R ³ through which the group L or a of the groups to which the group L binds may be substituted. Preference is given to compounds comprising structures of the formula (1), preferably representable by structures of the formula (1), in which the group L represents a bond or a group selected from the formulas (L ¹ -1) to ( ^L1-16 ) where the dashed bonds mark the attachment positions, Y ³ is the same or different on each occurrence, preferably O, S, NAr', NR ² , preferably O or S; the subscript k is 0 or 1, the subscript l is 0, 1 or 2, the subscript j is independently 0, 1, 2 or 3 for each occurrence; the subscript h is independently 0, 1, 2, 3 or 4 on each occurrence; the subscript g is 0, 1, 2, 3, 4 or 5; and the symbol R ² has the meaning given above, in particular for formula (1), where L is preferably a bond or an aromatic ring system having 5 to 40 aromatic ring atoms which does not include any heteroatoms. Furthermore, it can be provided that the group L in formula (1) is a bond and Y is selected from NR ² , NAr, O, S, preferably Y is NAr. For preferred embodiments of the structures/compounds of the formula (1), which are set out above and below, the statements made in relation to the radical L apply accordingly. Preferred aromatic or heteroaromatic ring systems 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 can be linked via the 1-, 2-, 3- or 4-position, spirobifluorene, which can be linked via the 1-, 2-, 3- or 4-position, naphthalene , in particular 1- or 2- linked naphthalene, indole, benzofuran, benzothiophene, carbazole, which can be linked via the 1-, 2-, 3-, 4- or 9-position, dibenzofuran, which via the 1-, 2- , 3- or 4-position, dibenzothiophene, which can 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 with one or more radicals R ² s can be substituted. Furthermore, it can be provided that the substituents R, R ¹ , R ² and R ³ according to the above formulas with the ring atoms of the ring system are not a fused aromatic or heteroaromatic ring system, preferably do not form a fused ring system. This includes the formation of a fused ring system with possible substituents R ⁴ , R ⁵ which can be attached to the radicals R, R ¹ , R ² , R ³ . If two radicals, which can be selected in particular from R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and/or R ¹¹ , form a ring system with one another, this can be mono- or polycyclic, aliphatic, heteroaliphatic, aromatic or heteroaromatic. The radicals which form a ring system with one another can be adjacent, ie these radicals are attached to the same carbon atom or to carbon atoms which are bonded directly to one another, or they can be further apart. Furthermore, the ring systems provided with the substituents R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and/or R ¹¹ can also be connected to one another via a bond, so that in this way a ring closure can be effected. In this case, each of the corresponding binding sites is preferably provided with a substituent R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and/or R ¹¹ . Provision can also be made for R, R ¹ , R ² and/or R ³ to be 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-75 and/or the group Ar and/or Ar' is selected identically or differently on each occurrence from the groups of the following formulas Ar-1 to Ar-75, where R ⁴ has the meanings given above, the dashed bond represents the point of attachment and the following also applies: Ar ¹ is identical or different on each occurrence, a bivalent aromatic or heteroaromatic ring system having 6 to 18 aromatic ring atoms, each with one or several radicals R ⁴ may be substituted; A is, identically or differently, on each occurrence C(R ⁴ )2, NR ⁴ , O 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 bonded directly to the corresponding radical; q is 0 or 1, where q=0 means that no group A is bonded to this position and radicals R ⁴ are bonded to the corresponding carbon atoms instead. The structures of the formulas (Ar-1) to (Ar-75) presented above represent preferred configurations of the radical Ar, as defined for example in structures of the formula (1), in which case the substituents R ⁴ in formulas (Ar -1) to (Ar-75) are to be replaced by R ² , where R ² is as defined above, in particular for formula (1). The structures of the formulas (Ar-1) to (Ar-75) set out above represent preferred configurations of the radicals Ar ^a , Ar ^b and Arc ^c , as defined for example for preferred connecting groups L, in which case the substituents R ⁴ in formulas (Ar-1) to (Ar-75) are to be replaced by R ² , where R ² has the meaning given above, in particular for formula (1). Furthermore, the radicals Ar ^b and Ar ^c include a further attachment point. Here, 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-75), preferred and structures of formulas (Ar-1), (Ar-2), (Ar-3), (Ar-12), (Ar-13), (Ar-14), (Ar-15), (Ar-16) are particularly preferred. If the groups mentioned above have several groups A for Ar, then all combinations from the definition of A are suitable for this. Preferred embodiments are then those in which one group A is NR ⁴ and the other group A is C(R ⁴ ) 2 or in which both groups A are NR ⁴ or in which both groups A are O. If A is NR ⁴ , the substituent R ⁴ which is bonded to the nitrogen atom is preferably an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms, which can also be substituted by one or more R ⁵ radicals. In a particularly preferred embodiment, this substituent R ⁴ is identical or different on each occurrence for an aromatic or heteroaromatic ring system with 6 to 24 aromatic ring atoms, in particular with 6 to 18 aromatic ring atoms, which has no fused aryl groups and which no fused heteroaryl groups in which two or more aromatic or heteroaromatic 6-ring groups are fused directly to one another, and which can each also be substituted by one or more R ⁵ radicals. Preference is given to phenyl, biphenyl, terphenyl and quaterphenyl with linkage patterns as listed above for Ar-1 to Ar-11, these structures being substituted by one or more R ⁵ radicals instead of R ⁴ can be, but are preferably unsubstituted. Triazine, pyrimidine and quinazoline are also preferred, as listed above for Ar-47 to Ar-50, Ar-57 and Ar-58, it being possible for these structures to be substituted by one or more R ⁵ radicals instead of by R ⁴ . If A is C(R ⁴ ) 2 , the substituents R ⁴ bonded to this carbon atom are preferably identical or different each time they occur for a linear alkyl group having 1 to 10 carbon atoms or for a branched or cyclic alkyl group 3 to 10 carbon atoms or an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms, which can also be substituted by one or more R ⁵ radicals. R ⁴ is very particularly preferably a methyl group or a phenyl group. The R ⁴ radicals can also form a ring system with one another, which leads to a spiro system. Preferred substituents R, R ¹ , R ² and R ³ are described below. In a preferred embodiment of the invention, R, R ¹ , R ² and R ³ are the same or different on each occurrence selected from the group consisting of H, D, F, CN, NO2, Si(R ⁴ )3, B(OR ⁴ )2, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, it being possible for each alkyl group to be substituted by one or more radicals R ⁴ , or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, preferably having 5 to 40 aromatic ring atoms, each of which may be substituted by one or more R ⁴ radicals. In a further preferred embodiment of the invention, R, R ¹ , R ² and R ³ are identical or different on each occurrence selected from the group consisting of H, D, F, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where each alkyl group may be substituted by one or more R ⁴ radicals, or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, preferably having 5 to 40 aromatic ring atoms, each may be substituted by one or more R ⁴ radicals. In a further preferred embodiment of the invention, R, R ¹ , R ² and R ³ are the same or different on each occurrence selected from the group consisting of H, D, an aromatic or heteroaromatic ring system having 6 to 30 aromatic ring atoms, which with one or several radicals R ⁴ can be substituted, or a group N(Ar')2. R, R ¹ , R ² are particularly preferably selected identically or differently on each occurrence 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 may be substituted by one or more R ⁴ radicals. Preferred aromatic or heteroaromatic ring systems R, R ¹ , R ² , R ³ 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 can be linked via the 1-, 2-, 3- or 4-position, spirobifluorene, which can be linked via the 1-, 2-, 3- or 4-position can be linked, naphthalene, in particular 1- or 2-linked naphthalene, indole, benzofuran, benzothiophene, carbazole, which can be linked via the 1-, 2-, 3- or 4-position, dibenzofuran, which can be linked via the 1-, 2-, 3- or 4-position, dibenzothiophene, which can 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 with one or more en radicals R ⁴ may be substituted. The structures Ar-1 to Ar-75 listed above are particularly preferred, 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-75), preferred and structures of formulas (Ar-1), (Ar-2 ), (Ar-3), (Ar-12), (Ar-13), (Ar-14), (Ar-15), (Ar-16) are particularly preferred. Other suitable groups R, R ¹ , R ² and R ³ are groups of the formula -Ar ⁴ -N (Ar ² ) (Ar ³ ), where Ar ² , Ar ³ and Ar ⁴ are identical or different on each occurrence for an aromatic or heteroaromatic ring system with 5 to 24 aromatic ring atoms, which each may be substituted with one or more R ⁴ groups. The total number of aromatic ring atoms of Ar ² , Ar ³ and Ar ⁴ is a maximum of 60 and preferably a maximum of 40. Ar ⁴ and Ar ² can be connected to one another and/or Ar ² and Ar ³ can also be connected to one another by a group selected from C(R ⁴ )2, NR ⁴ , O or S can be connected. Ar ⁴ and Ar ² are preferably linked to one another or Ar ² and Ar ³ to one another in each case 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 are connected to one another. Ar ⁴ is preferably an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, preferably having 6 to 12 aromatic ring atoms, which can each be substituted by one or more R ⁴ radicals. Ar ⁴ is particularly preferably selected from the group consisting of ortho-, meta- or para-phenylene or ortho-, meta- or para-biphenyl, which can each be substituted by one or more radicals R ⁴ , but are preferably unsubstituted. Most preferably Ar ⁴ is an unsubstituted phenylene group. Ar ² and Ar ³ are preferably identical or different on each occurrence and are an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, which can each be substituted by one or more R ⁴ radicals. Particularly preferred Ar ² and Ar ³ groups are identical or different on each occurrence and are 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-, 3- or 4-carbazole, 1-, 2-, 3- or 4-dibenzofuran, 1-, 2-, 3- or 4-dibenzothiophene, indenocarbazole, indolocarbazole, 2-, 3 - or 4-pyridine, 2-, 4- or 5-pyrimidine, pyrazine, pyridazine, triazine, phenanthrene or triphenylene, each of which may be substituted by one or more R ¹ radicals. Ar ² and Ar ³ are very particularly preferably the same or different 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 ter - phenyl, 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. In a further preferred embodiment of the invention, R ⁴ is selected identically or differently on each occurrence from the group consisting of H, D, F, CN, a straight-chain alkyl group having 1 to 10 carbon atoms or a branched or cyclic alkyl group having 3 to 10 carbon atoms, it being possible for the alkyl group to be substituted by one or more R ² radicals, or an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, each of which can be substituted by one or more R ⁵ radicals. In a particularly preferred embodiment of the invention, R ⁴ is identical or different on each occurrence selected from the group consisting of H, a straight-chain alkyl group having 1 to 6 carbon atoms, in particular having 1, 2, 3 or 4 carbon atoms, or a branched or cyclic alkyl group having 3 to 6 carbon atoms, where the alkyl group may be substituted by one or more radicals R ⁵ , but is preferably unsubstituted, or an aromatic or heteroaromatic ring system having 6 to 13 aromatic ring atoms, each of which is substituted by one or more radicals R ⁵ may be substituted, but is preferably unsubstituted. In a further preferred embodiment of the invention, R ⁵ is the same or different on each occurrence of H, an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms which is substituted with an alkyl group having 1 to 4 carbon atoms may be, but is preferably unsubstituted. In compounds according to the invention which are processed by vacuum evaporation, the alkyl groups preferably have no more than five carbon atoms, particularly preferably no more than 4 carbon atoms, very particularly preferably no more than 1 carbon atom. Also suitable for compounds which are processed from solution are compounds which are substituted with alkyl groups, in particular branched alkyl groups, having up to 10 carbon atoms or which are substituted with oligoarylene groups, for example ortho-, meta-, para- or branched terphenyl - or quaterphenyl groups, are substituted. If the compounds of the formula (1) or the preferred embodiments are used as matrix material for a phosphorescent emitter or in a layer which is directly adjacent to a phosphorescent layer, it is also preferred if the compound does not contain any Contains fused aryl or heteroaryl groups in which more than two six-membered rings are fused directly to one another. An exception to this are phenanthrene and triphenylene, which can be preferred due to their high triplet energy despite the presence of fused aromatic six-membered rings. Furthermore, preferred compounds according to the invention are characterized in that they can be sublimed. These compounds generally have a molar mass of less than about 1200 g/mol. Furthermore, it can be provided that the compound comprising structures according to formula (1), preferably the compound according to formula (1) or a preferred embodiment of this structure/compound is not in direct contact with a metal atom, preferably is not a ligand for a metal complex. The preferred embodiments mentioned above can be combined with one another at will within the limitations defined in claim 1. In a particularly preferred embodiment of the invention, the preferences mentioned above occur simultaneously. Examples of preferred compounds according to the embodiments listed above are the compounds listed in the table below.

The basic structure of the compounds according to the invention can be represented according to the routes outlined in the following schemes. The individual synthesis steps, such as CC coupling reactions according to Suzuki, CN coupling reactions according to Hartwig-Buchwald or cyclization reactions, are known in principle to those skilled in the art. Further information on the synthesis of the compounds according to the invention can be found in the synthesis examples. A possible synthesis of the basic structure is shown in Scheme 1. This can take place in accordance with the reactions set out in US 10/312455 B2. Alternatively, coupling can be done with the amino group of an optionally substituted carbazole, followed by a ring closure reaction. Schemes 3 to 5 show various ways of introducing the fluorene, dibenzofuran, dibenzothiophene or carbazole group. A fluorene, dibenzofuran, dibenzothiophene or carbazole compound substituted with a suitable reactive group, for example a boron-containing group, can be introduced in a Suzuki coupling reaction, as shown in Schemes 3 to 5. Scheme 1 Scheme 2

Scheme 3 Scheme 4 Scheme 5

Scheme 6 The meaning of the symbols used in Schemes 1 to 6 essentially corresponds to that which was defined for formula (1), with numbering and a complete representation of all symbols being dispensed with for reasons of clarity. A further subject of the present invention is therefore a process for preparing a compound according to the invention, in which a thiofuran compound is reacted with an aromatic or heteroaromatic nitrogen compound by means of a coupling reaction. Formulations of the compounds according to the invention are required for the processing of the compounds according to the invention from the liquid phase, for example by spin coating or by printing processes. These formulations can be, for example, solutions, dispersions or be emulsions. It may be preferable to use mixtures of two or more solvents for this. Examples of suitable and preferred solvents are toluene, anisole, o-, m- or p-xylene, methyl benzoate, mesitylene, tetralin, veratrol, THF, methyl THF, THP, chlorobenzene, dioxane, phenoxytoluene, especially 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, ^-terpineol, benzothiazole, butyl benzoate, cumene, cyclohexanol, cyclohexanone, cyclohexylbenzene, decalin, dodecylbenzene, ethyl benzoate, indane, NMP, p-cymene , phenetole, 1,4-diisopropylbenzene, dibenzyl ether, diethylene glycol butyl methyl ether, triethylene glycol butyl methyl 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-dimethylph enyl)ethane, 2-methylbiphenyl, 3-methylbiphenyl, 1-methylnaphthalene, 1-ethylnaphthalene, ethyl octanoate, sebacic acid diethyl ester, octyl octanoate, heptyl benzene, menthyl isovalerate, cyclohexyl hexanoate or mixtures of these solvents. A further object of the present invention is therefore a formulation or a composition containing at least one compound according to the invention and at least one further compound. The further connection can be, for example, a solvent, in particular one of the abovementioned solvents or a mixture of these solvents. If the further compound comprises a solvent, then this mixture is referred to herein as a formulation. However, the further compound can also be at least one further organic or inorganic compound which is also used in the electronic device, for example an emitting compound and/or a further matrix material. Suitable emitting compounds and other matrix materials are listed below in connection with the organic electroluminescent device. The further connection can also be polymeric. Another object of the present invention is the use of a compound according to the invention in an electronic device, in particular in an organic electroluminescent device. Yet another subject matter of the present invention is an electronic device containing at least one connection according to the invention. An electronic device within the meaning of the present invention is a device which contains at least one layer which contains at least one organic compound. In this case, the component can also contain inorganic materials or also layers which are made up entirely of inorganic materials. Electronic device selected from the group consisting of organic electroluminescent devices (OLEDs, sOLED, 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, sOLED, 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. The organic electroluminescent device contains cathode, anode and at least one emitting layer. In addition to these layers, it can also contain other 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. Likewise, interlayers can be introduced between two emitting layers, which have an exciton-blocking function, for example. However, it should be pointed out that each of these layers does not necessarily have to be present. In this case, the organic electroluminescent device can contain an emitting layer, or it can contain a plurality of emitting layers. If a plurality of emission layers are present, these preferably have a total of a plurality of emission maxima between 380 nm and 750 nm, resulting in white emission overall, ie different emitting compounds which can fluoresce or phosphorescence are used in the emitting layers. Systems with three emitting layers are particularly preferred, with the three layers showing blue, green and orange or red emission. The organic electroluminescent device according to the invention can also be a tandem electroluminescent device, in particular for white-emitting OLEDs. The connection according to the invention can be used in different layers, depending on the precise structure. Preference is given to an organic electroluminescent device containing a compound of the formula (1) or the preferred embodiments outlined above in an emitting layer as matrix material for phosphorescent emitters or for emitters which exhibit TADF (thermally activated delayed fluorescence), in particular for phosphorescent emitters. Furthermore, the compound according to the invention can also be used in an electron transport layer and/or in a hole transport 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 or yellow, preferably green phosphorescent emitters, in an emitting layer or as a hole-transport or electron-blocking material in a hole-transport or electron-blocking layer preferably as a matrix material in an emitting layer. If the compound according to the invention is used as matrix material for a phosphorescent compound in an emitting layer, it is preferably used in combination with one or more phosphorescent materials (triplet emitters). Phosphorescence within the meaning of this invention is understood as meaning luminescence from an excited state with a higher spin multiplicity, ie 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 regarded as phosphorescent compounds. The mixture of the compound according to the invention and the emitting compound contains between 99 and 1% by volume, preferably between 98 and 10% by volume, particularly preferably between 97 and 60% by volume, in particular between 95 and 80% by volume. -% of the compound according to the invention based on the total mixture of emitter and matrix material. Correspondingly, the mixture contains between 1 and 99% by volume, preferably between 2 and 90% by volume, particularly preferably between 3 and 40% by volume, in particular between 5 and 20% by volume, of the emitter, based on the total mixture emitter and matrix material. In one embodiment of the invention, the compound according to the invention is used as the only matrix material (“single host”) for the phosphorescent emitter. 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 a further matrix material. Suitable matrix materials which 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. B. according to WO 2004/013080, WO 2004/093207, WO 2006/005627 or WO 2010/006680, triarylamines, carbazole derivatives, z. B. CBP (N, N-biscarbazolylbiphenyl) or in WO 2005/039246, US 2005/0069729, JP 2004/288381, EP 1205527, WO 2008/086851 or WO 2013/041176, indolocarbazole derivatives, z. B. according to WO 2007/063754 or WO 2008/056746, indenocarbazole derivatives, z. B. according to WO 2010/136109, WO 2011/000455, WO 2013/041176 or WO 2013/056776, azacarbazole derivatives, e.g. according to EP 1617710, EP 1617711, EP 1731584, JP 2005/347160, bipolar matrix materials, e.g. B. according to WO 2007/137725, silanes, z. B. according to WO 2005/111172, azaborole or boron ester, z. B. according to WO 2006/117052, triazine derivatives, z. 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. B. according to EP 652273 or WO 2009/062578, diazasilol or tetra azasilol derivatives, z. B. according to WO 2010/054729, diazaphosphole derivatives, z. B. according to WO 2010/054730, bridged carbazole derivatives, z. B. according to WO 2011/042107, WO 2011/060867, WO 2011/088877 and WO 2012/143080, triphenylene derivatives, z. B. according to WO 2012/048781, dibenzofuran derivatives, z. B. according to WO 2015/169412, WO 2016/015810, WO 2016/023608, WO 2017/148564 or WO 2017/148565 or biscarbazoles, z. B. according to JP 3139321 B2. A further phosphorescent emitter, which emits at a shorter wavelength than the actual emitter, can also be present in the mixture as a co-host. Particularly good results are achieved when a red phosphorescent emitter is used as the emitter and a yellow phosphorescent emitter is used as the co-host in combination with the compound according to the invention. Furthermore, a compound can be used as a co-host that does not participate, or does not participate to a significant extent, in charge transport, as described, for example, in WO 2010/108579. In particular, in combination with the compound according to the invention, suitable co-matrix material are compounds which have a large band gap and do not themselves 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 in WO 2010/006680. Particularly preferred co-host materials which can be used in combination with the compounds according to the invention are compounds according to one of the formulas (7), (8), (9) or (10), where the following applies to the symbols and indices used: R ⁶ is identical or different on each occurrence, H, D, F, Cl, Br, I, N(R ⁷ )2, N(Ar″)2, CN, NO2, OR ⁷ , SR ⁷ , COOR ⁷ , C(=O)N(R ⁷ )2, Si(R ⁷ )3, B(OR ⁷ )2, C(=O)R ⁷ , P(=O)(R ⁷ )2, S(=O)R ⁷ , S(=O)2R ⁷ , OSO2R ⁷ , a straight-chain alkyl group with 1 to 20 carbon atoms or an alkenyl or alkynyl group with 2 to 20 carbon atoms or a branched or cyclic one Alkyl group with 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group can each be substituted with one or more radicals R ⁴ and where one or more non-adjacent CH2 groups are replaced by Si(R ⁷ )2, C =O, NR ⁷ , O, S or CONR ⁷ can be replaced, or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, preferably having 5 to 40 aromatic ring atoms, each of which can be substituted by one or more R ⁷ radicals; two radicals R ⁶ can also form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system with one another, the radicals R ⁶ preferably not forming such a ring system; Ar'' is identical or different on each occurrence, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can be substituted by one or more radicals R ⁷ ; A ¹ is C(R ⁷ )2, NR ⁷ , O or S; Ar ⁵ is identical or different on each occurrence and is an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can be substituted with one or more R ⁷ radicals; R ⁷ is the same or different on each occurrence: H, D, F, Cl, Br, I, N(R ⁸ )2, CN, NO2, OR ⁸ , SR ⁸ , Si(R ⁸ )3, B(OR ⁸ ) 2, C(=O)R ⁸ , P(=O)(R ⁸ )2, S(=O)R ⁸ , S(=O)2R ⁸ , OSO2R ⁸ , a straight-chain alkyl group with 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, it being possible for the alkyl, alkenyl or alkynyl group to be substituted in each case by one or more radicals R ⁸ , with one or more non-adjacent CH2 groups by Si (R ⁸ ) 2, C = O, NR ⁸ , O, S or CONR ⁸ can be replaced, or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, each by one or more radicals R ⁸ may be substituted; two or more radicals R ⁷ can together form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system, preferably the radicals R ⁷ do not form such a ring system; R ⁸ is identical or different on each occurrence and is H, D, F or an aliphatic, aromatic or heteroaromatic organic radical, in particular a hydrocarbon radical, having 1 to 20 carbon atoms, in which one or more H atoms can also be replaced by F ; s is the same or different on each occurrence and is 0, 1, 2, 3 or 4, preferably 0 or 1 and very preferably 0; t is the same or different on each occurrence and is 0, 1, 2 or 3, preferably 0 or 1 and very preferably 0; u is the same or different on each occurrence and is 0, 1 or 2, preferably 0 or 1 and very preferably 0. The sum of the indices s, t and u in compounds of the formulas (7), (8), (9) or (10 ) is preferably at most 6, particularly preferably at most 4 and particularly preferably at most 2. In a preferred embodiment of the invention, R ⁶ is the same or different on each occurrence selected from the group consisting of H, D, F, CN, NO2, Si(R ⁷ )3, B(OR ⁷ )2, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, it being possible for the alkyl group to be substituted by one or more radicals R ⁷ in each case, or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, preferably having 5 to 40 aromatic ring atoms, which can each be substituted by one or more R ⁷ radicals. In a further preferred embodiment of the invention, R ⁶ is identical or different on each occurrence selected from the group consisting of H, D, F, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms. Atoms, it being possible for the alkyl group to be substituted by one or more R ⁷ radicals, or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, preferably having 5 to 40 aromatic ring atoms, which can each be substituted by one or more R ⁷ radicals . In a further preferred embodiment of the invention, R ⁶ is identical or different on each occurrence selected from the group consisting of H, D, an aromatic or heteroaromatic ring system having 6 to 30 aromatic ring atoms, which can be substituted by one or more radicals R ⁷ , or a group N(Ar'')2. R ⁶ is particularly preferably the same or different on each occurrence selected from the group consisting of H or one 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 can be substituted by one or more R ⁷ radicals. Preferred aromatic or heteroaromatic ring systems R ⁶ 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 can be linked via the 1-, 2-, 3- or 4-position, spirobifluorene, which can be linked via the 1-, 2-, 3- or 4- Position can be linked, naphthalene, in particular 1- or 2-linked naphthalene, indole, benzofuran, benzothiophene, carbazole, which can be linked via the 1-, 2-, 3- or 4-position, dibenzofuran, which via the 1-, 2-, 3- or 4-position can be linked, dibenzothiophene, which can 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 having one or more radicals R ⁷ may be substituted. The structures Ar-1 to Ar-75 listed above are particularly preferred, 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-75), preferred and structures of formulas (Ar-1), (Ar-2 ), (Ar-3), (Ar-12), (Ar-13), (Ar-14), (Ar-15), (Ar-16) are particularly preferred. In the structures Ar-1 to Ar-75 presented above, the substituents R ⁴ in relation to the radicals R ⁶ and Ar'' are to be replaced by the corresponding radicals R ⁷ . The preferences set out above for the groups R ² and R ³ apply correspondingly to the group R ⁶ . Further suitable groups R ⁶ are groups of the formula -Ar ⁴ -N(Ar ² )(Ar ³ ), where Ar ² , Ar ³ and Ar ⁴ are identical or different on each occurrence for an aromatic or heteroaromatic ring system having 5 to 24 aromatic matic ring atoms, each of which may be substituted by one or more R ⁴ radicals. The total number of aromatic ring atoms of Ar ² , Ar ³ and Ar ⁴ is a maximum of 60 and preferably a maximum of 40. Other preferences for the groups Ar ² , Ar ³ and Ar ⁴ have been explained above and apply accordingly. Provision can furthermore be made for the substituents R ⁶ according to the above formulas to form no fused aromatic or heteroaromatic ring system, preferably no fused ring system, with the ring atoms of the ring system. This includes the formation of a fused ring system with possible substituents R ⁷ , R ⁸ which can be attached to the R ⁶ radicals. If A ¹ is NR ⁷ , the substituent R ⁷ which is bonded to the nitrogen atom is preferably an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms, which can also be substituted by one or more R ⁸ radicals. In a particularly preferred embodiment, this substituent R ⁷ is identical or different on each occurrence for an aromatic or heteroaromatic ring system with 6 to 24 aromatic ring atoms, in particular with 6 to 18 aromatic ring atoms, which has no fused aryl groups and which no fused heteroaryl groups in which two or more aromatic or heteroaromatic 6-ring groups are fused directly to one another, and which can also be substituted by one or more R ⁸ radicals. Preference is given to phenyl, biphenyl, terphenyl and quaterphenyl with linkage patterns as listed above for Ar-1 to Ar-11, it being possible for these structures to be substituted by one or more R ⁸ radicals instead of R ⁴ , but they are preferably unsubstituted. Triazine, pyrimidine and quinazoline are also preferred, as listed above for Ar-47 to Ar-50, Ar-57 and Ar-58, it being possible for these structures to be substituted by one or more R ⁸ radicals instead of by R ⁴ . If A ¹ is C(R ⁷ ) 2 , the substituents R ⁷ bonded to this carbon atom are preferably identical or different on each occurrence and are a linear alkyl group having 1 to 10 carbon atoms or a branched or cyclic alkyl group with 3 to 10 carbon atoms or for an aromatic or heteroaromatic ring system with 5 to 24 aromatic ring atoms, which can also be substituted by one or more radicals R ⁸ . R ⁷ is very particularly preferably a methyl group or a phenyl group. The R ⁷ radicals can also form a ring system with one another, which leads to a spiro system. Furthermore, preferred co-host materials which can be used in combination with the compounds according to the invention are compounds according to one of the formulas (11), (12), (13), (14), (15), (16), (17) or (18), where the following applies to the symbols and indices used: X ² represents N or CR ⁹ , with the proviso that no more than two of the groups X ² in a cycle represent N, preferably at least one X ² represents N; L ² represents a linking group, which is preferably selected from a bond or an aromatic or heteroaromatic Ring system with 5 to 40 aromatic ring atoms, which can be substituted with one or more radicals R ⁹ , particularly preferably a bond; A ² is C(R ¹⁰ )2, NR ¹⁰ , O or S; Ar ⁶ is identical or different on each occurrence and is an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can be substituted with one or more R ¹⁰ radicals; R ⁹ is identical or different on each occurrence H, D, F, Cl, Br, I, N(R ¹⁰ )2, N(Ar''')2, CN, NO2, OR ¹⁰ , SR ¹⁰ , COOR ¹⁰ , C(=O)N( ^R10 )2, Si( ^R10 )3, B( ^OR10 )2, C(=O) ^R10 , P(=O)( ^R10 )2, S(=O) R ¹⁰ , S(=O)2R ¹⁰ , OSO2R ¹⁰ , a straight-chain alkyl group with 1 to 20 carbon atoms or an alkenyl or alkynyl group with 2 to 20 carbon atoms or a branched or cyclic alkyl group with 3 to 20 carbon atoms -Atoms, where the alkyl, alkenyl or alkynyl group can each be substituted by one or more radicals R ⁴ and where one or more non-adjacent CH2 groups are replaced by Si(R ¹⁰ )2, C=O, NR ¹⁰ , O, S or CONR ¹⁰ can be replaced, or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, preferably having 5 to 40 aromatic ring atoms, which can each be substituted by one or more R ¹⁰ radicals; two radicals R ⁹ can also form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system with one another, the radicals R ⁹ preferably not forming such a ring system; Ar''' is the same or different on each occurrence and is an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can be substituted with one or more R ¹⁰ radicals. R ¹⁰ is the same or different on each occurrence, H, D, F , Cl, Br, I, N(R ¹¹ )2, CN, NO2, OR ¹¹ , SR ¹¹ , Si(R ¹¹ )3, B(OR ¹¹ )2, C(=O)R ¹¹ , P(=O )(R ¹¹ )2, S(=O)R ¹¹ , S(=O)2R ¹¹ , OSO2R ¹¹ , a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, the alkyl, alkenyl or alkynyl group each having one or several radicals R ¹¹ can be substituted, in which case one or more non-adjacent CH2 groups can be replaced by Si(R ¹¹ )2, C═O, NR ¹¹ , O, S or CONR ¹¹ , or an aromatic or heteroaromatic ring system with 5 up to 40 aromatic ring atoms, each of which can be substituted by one or more radicals R ¹¹ ; two or more radicals R ¹⁰ can together form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system, preferably the radicals R ¹⁰ do not form such a ring system; R ¹¹ is the same or different on each occurrence and is H, D, F or an aliphatic, aromatic or heteroaromatic organic radical, in particular a hydrocarbon radical, having 1 to 20 carbon atoms, in which one or more H atoms can also be replaced by F v is the same or different on each occurrence and is 0, 1, 2, 3 or 4, preferably 0 or 1 and very preferably 0; t is the same or different on each occurrence and is 0, 1, 2 or 3, preferably 0 or 1 and very preferably 0; x is the same or different on each occurrence and is 0, 1, 2, 3 or 4, preferably 0 or 1 and very preferably 0; z is the same or different on each occurrence and is 0, 1 or 2, preferably 0 or 1 and very preferably 0, the sum of x and 2z being at most 4, preferably at most 2. The sum of the indices v, t, x and z in compounds of the formulas (11), (12), (13), (14), (15), (16), (17) or (18) is preferably at most 6 , particularly preferably at most 4 and particularly preferably at most 2. The group L ² represents a linking group, which is preferably selected from a bond or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can be substituted by one or more radicals R ⁹ , particularly preferably a bond. Preferably, the group L ² with the groups to which the group L ² according to formulas (11), (12), (13), (14), (15), (16), (17) or (18) or is bound to the preferred embodiments of this formula form a continuous conjugation. In a further preferred embodiment of the invention, L represents a bond or 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 can be substituted by one or more R ⁹ radicals, but is preferably unsubstituted, where R ⁹ can have the meaning mentioned above, in particular for formulas (11), (12), (13), (14), (15), (16), (17) or (18). L ² particularly preferably represents a bond or an aromatic ring system having 6 to 10 aromatic ring atoms or a heteroaromatic ring system having 6 to 13 heteroaromatic ring atoms, which can each be substituted by one or more radicals R ⁹ , but is preferably unsubstituted, where R ⁹ can have the meaning mentioned above, in particular for formulas (11), (12), (13), (14), (15), (16), (17) or (18). Furthermore, the symbol L ² set out, inter alia, in formulas (11), (12), (13), (14), (15), (16), (17) or (18) is preferably identical or different on each occurrence 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 directly, ie via an atom of the aromatic or heteroaromatic group , is bound to the respective atom of the further group. Furthermore, it can be provided that the group L ² set out in formulas (11), (12), (13), (14), (15), (16), (17) or (18) is an aromatic ring system with at most two fused aromatic and/or heteroaromatic 6-rings, preferably no fused aromatic or heteroaromatic ring system. Accordingly, naphthyl structures are preferred over anthracene structures. Furthermore, fluorenyl, spirobifluorenyl, dibenzofuranyl and/or dibenzothienyl structures are preferred over naphthyl structures. Particularly preferred are structures that do not exhibit condensation, such as phenyl, biphenyl, terphenyl and/or quaterphenyl structures. Examples of suitable aromatic or heteroaromatic ring systems L ² are selected from the group consisting of ortho-, meta- or para-phenylene, ortho-, meta- or para-biphenylene, terphenylene, in particular branched terphenylene, quaterphenylene, in particular branched quaterphenylene, fluorenylene, Spirobifluorenylene, dibenzofuranylene, dibenzothienylene and carbazolylene, each of which may be substituted by one or more R ⁹ radicals, but are preferably unsubstituted. Furthermore, it can be provided that the group L ² set out, inter alia, in formulas (11), (12), (13), (14), (15), (16), (17) or (18) has at most 1 nitrogen atom, preferably at most 2 heteroatoms, particularly preferably at most one heteroatom and particularly preferably no heteroatom. Furthermore, it can be provided that the group L ² does not form a fused aromatic or heteroaromatic ring system with the groups to which the group L ² binds, this including the radicals R ⁹ , R ¹⁰ or R ¹¹ through which the group L ² or one of the groups to which the group L ² binds may be substituted. The group L ² is particularly preferably a bond or a group which is selected from the formulas (L ¹ -1) to (L ¹ -13), such as these were previously defined, wherein the substituents R ² in the structures of formulas (L ¹ -1) to (L ¹ -13) are to be replaced by R ⁹ . In a preferred embodiment of the invention, R ⁹ is the same or different on each occurrence selected from the group consisting of H, D, F, CN, NO2, Si(R ¹⁰ )3, B(OR ¹⁰ )2, a straight-chain alkyl group with 1 to 20 carbon atoms or a branched or cyclic alkyl group with 3 to 20 carbon atoms, where the alkyl group can be substituted with one or more radicals R ¹⁰ , or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, preferably with 5 to 40 aromatic ring atoms, each of which may be substituted by one or more R ¹⁰ radicals. In a further preferred embodiment of the invention, R ⁹ is the same or different on each occurrence and is selected from the group consisting of H, D, F, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms. Atoms, where the alkyl group can be substituted by one or more radicals R ¹⁰ , or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, preferably with 5 to 40 aromatic ring atoms, which can each be substituted by one or more radicals R ¹⁰ . In a further preferred embodiment of the invention, R ⁹ is identical or different on each occurrence selected from the group consisting of H, D, an aromatic or heteroaromatic ring system having 6 to 30 aromatic ring atoms, which can be substituted by one or more radicals R ¹⁰ , or a group N(Ar''')2. R ⁹ is particularly preferably the same or different 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 may be substituted by one or more R ¹⁰ radicals. Preferred aromatic or heteroaromatic ring systems R ⁹ 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 has the 1-, 2-, 3- or 4-position can be linked, spirobifluorene, which can be linked via the 1-, 2-, 3- or 4-position, naphthalene, in particular 1- or 2-linked naphthalene, indole, benzofuran, benzothiophene, carbazole, which via the 1-, 2-, 3- or 4-position can be linked, dibenzofuran, which can be linked via the 1-, 2-, 3- or 4-position, dibenzothiophene, which can be linked via the 1-, 2-, 3- or 4-position can be linked, indenocarbazole, indolocarbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene or triphenylene, each of which can be substituted with one or more radicals R ¹⁰ . The structures Ar-1 to Ar-75 listed above are particularly preferred, 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-75), preferred and structures of formulas (Ar-1), (Ar-2 ), (Ar-3), (Ar-12), (Ar-13), (Ar-14), (Ar-15), (Ar-16) are particularly preferred. In the structures Ar-1 to Ar-75 presented above, the substituents R ⁴ in relation to the radicals R ⁶ and Ar'' are to be replaced by the corresponding radicals R ¹⁰ . The preferences set out above for the groups R ² and R ³ apply correspondingly to the group R ⁹ . Further suitable groups R ⁹ are groups of the formula -Ar ⁴ -N(Ar ² )(Ar ³ ), where Ar ² , Ar ³ and Ar ⁴ are identical or different on each occurrence for an aromatic or heteroaromatic ring system having 5 to 24 aromatic matic ring atoms, each of which may be substituted by one or more R ⁴ radicals. The total number of aromatic ring atoms of Ar ² , Ar ³ and Ar ⁴ is a maximum of 60 and preferably a maximum of 40. Other preferences for the groups Ar ² , Ar ³ and Ar ⁴ have been explained above and apply accordingly. Provision can furthermore be made for the substituents R ⁹ according to the above formulas to form no fused aromatic or heteroaromatic ring system, preferably no fused ring system, with the ring atoms of the ring system. This includes the formation of a fused ring system with possible substituents R ¹⁰ , R ¹¹ which can be attached to the R ⁹ groups. If A ² is NR ¹⁰ , the substituent R ¹⁰ which is bonded to the nitrogen atom is preferably an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms, which can also be substituted by one or more R ¹¹ radicals. In a particularly preferred embodiment, this substituent R ¹⁰ is identical or different on each occurrence for an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, in particular having 6 to 18 aromatic ring atoms, which has no fused aryl groups and which has no fused heteroaryl groups in which two or more aromatic or heteroaromatic 6-ring groups are fused directly to one another, and which in each case can also be substituted by one or more radicals R ¹¹ . Preference is given to phenyl, biphenyl, terphenyl and quaterphenyl with linkage patterns as listed above for Ar-1 to Ar-11, it being possible for these structures to be substituted by one or more radicals R ¹¹ instead of by R ⁴ , but they are preferably unsubstituted. Triazine, pyrimidine and quinazoline are also preferred, as listed above for Ar-47 to Ar-50, Ar-57 and Ar-58, it being possible for these structures to be substituted by one or more R ¹¹ radicals instead of by R ⁴ . If A ² is C(R ¹⁰ ) 2 , the substituents R ¹⁰ bonded to this carbon atom are preferably identical or different on each occurrence for a linear alkyl group having 1 to 10 carbon atoms or for a branched or cyclic alkyl group with 3 to 10 carbon atoms or for an aromatic or heteroaromatic ring system with 5 to 24 aromatic ring atoms, which can also be substituted by one or more radicals R ¹¹ . R ¹⁰ very particularly preferably represents a methyl group or a phenyl group. The R ¹⁰ radicals can also form a ring system with one another, which leads to a spiro system. Preferred aromatic or heteroaromatic ring systems Ar ⁵ and/or Ar ⁶ 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 via the 1-, 2-, 3- or 4-position, spirobifluorene, which can be linked via the 1-, 2-, 3- or 4-position, naphthalene, in particular 1- or 2-linked naphthalene, indole, benzofuran, benzothiophene, carbazole, which via the 1-, 2-, 3- or 4-position can be linked, dibenzofuran, which can be linked via the 1-, 2-, 3- or 4-position, dibenzothiophene, which can be linked via the 1-, 2-, 3- - or 4-position can be linked, indenocarbazole, indolocarbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene or triphenylene, each of which can be substituted with one or more radicals R ⁷ or R ¹⁰ . The groups Ar ⁵ and/or Ar ⁶ are particularly preferably selected independently of one another from the groups of the formulas Ar-1 to Ar-75 set out 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-75) , 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. In the structures Ar-1 to Ar-75 presented above, the substituents R ⁴ in relation to the radicals Ar ⁵ are to be replaced by the corresponding radicals R ⁷ or R ¹⁰ . In another preferred embodiment of the invention, R ⁷ and/or R ¹⁰ is the same or different on each occurrence and is selected from the group consisting of H, D, F, CN, a straight-chain alkyl group having 1 to 10 carbon atoms or a branched or cyclic one Alkyl group with 3 to 10 carbon atoms, where the alkyl group can be substituted with one or more radicals R ⁸ or R ¹¹ , or an aromatic or heteroaromatic ring system with 6 to 24 aromatic ring atoms, each of which is substituted by one or more radicals R ⁸ or R ¹¹ may be substituted. In a particularly preferred embodiment of the invention, R ⁷ and/or R ¹⁰ is the same or different on each occurrence and is selected from the group consisting of H, a straight-chain alkyl group having 1 to 6 carbon atoms, in particular having 1, 2, 3 or 4 carbon atoms -Atoms, or a branched or cyclic alkyl group having 3 to 6 carbon atoms, wherein the alkyl group may be substituted by one or more radicals R ⁸ or R ¹¹ , but is preferably unsubstituted, or an aromatic or heteroaromatic ring system having 6 to 13 aromatic ring atoms, which can each be substituted by one or more radicals R ⁸ or R ¹¹ , but is preferably unsubstituted. In a further preferred embodiment of the invention, R ⁸ and/or R ¹¹ is the same or different on each occurrence of H, an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms, which with an alkyl group having 1 to 4 carbon atoms may be substituted, but is preferably unsubstituted. Preferred embodiments of the compounds of the formulas (7) and (8) are the compounds of the following formulas (7a) and (8a), where R ⁶ , Ar ⁵ and A ¹ have the meanings mentioned above, in particular for formula (7) or (8). In a preferred embodiment of the invention, A ¹ in formula (8a) is C(R ⁷ )2. Preferred embodiments of the compounds of the formulas (7a) or (8a) are the compounds of the following formulas (7b) or (8b),

where R ⁶ , Ar ⁵ and A ¹ have the meanings mentioned above, in particular for formula (7) or (8). In a preferred embodiment of the invention, A ¹ in formula (8b) is C(R ⁷ )2. Examples of suitable compounds of the formula (7), (8), (9) or (10) are the compounds shown below.

Surprising advantages can be achieved by combining at least one compound of the formula (1) or its preferred embodiments described above with a compound of one of the formulas (7), (8), (9) or (10). Another subject of The present invention is therefore a composition containing at least one compound according to formula (1) or the preferred embodiments thereof set out above and at least one further matrix material, wherein the further matrix material is selected from compounds according to one of the formulas (7), (8), (9 ) or (10). Provision can preferably be made for the composition to consist of at least one compound of the formula (1) or the preferred embodiments thereof set out above and at least one compound of one of the formulas (7), (8), (9) or (10). These compositions are particularly suitable as so-called premix mixtures, which can be vaporized together. By combining at least one compound of the formula (1) or the preferred embodiments thereof set out above with a compound of one of the formulas (11), (12), (13), (14), (15), (16), (17 ) or (18) surprising advantages can be achieved. A further subject of the present invention is therefore a composition containing at least one compound according to formula (1) or the preferred embodiments thereof set out above and at least one further matrix material, wherein the further matrix material is selected from compounds according to one of the formulas (11), (12 ), (13), (14), (15), (16), (17) or (18). It can preferably be provided that the composition consists of at least one compound according to formula (1) or the preferred embodiments thereof set out above and at least one compound according to one of the formulas (11), (12), (13), (14), (15) , (16), (17) or (18). These compositions are particularly suitable as so-called premix mixtures, which can be vaporized together. Furthermore, it can preferably be provided that the composition consists of at least one compound according to formula (1) or the preferred embodiments thereof set out above and at least one compound according to one of the formulas (7), (8), (9), (10), (11 ), (12), (13), (14), (15), (16), (17) or (18). These compositions are suitable in particular as so-called premix mixtures that can be vaporized together. The compounds of one of the formulas (7), (8), (9), (10), (11), (12), (13), (14), (15), (16), (17 ) or (18) are each used individually or as a mixture of two, three or more compounds of the respective structures. Furthermore, the compounds of the formulas (7), (8), (9), (10), (11), (12), (13), (14), (15), (16), (17) or (18) used singly or as a mixture of two, three or more compounds of different structures. The compound of the formula (1) or its preferred embodiments described above preferably has a mass fraction in the composition in the range from 10% by weight to 95% by weight, preferably in the range from 15% by weight to 90% by weight. , and more preferably in the range of 40% to 70% by weight based on the total weight of the composition. Furthermore, it can be provided that the compounds according to one of the formulas (7), (8), (9), (10), (11), (12), (13), (14), (15), (16 ), (17) or (18) in the composition a mass fraction in the range from 5% to 90% by weight, preferably in the range from 10% to 85% by weight, more preferably in the range of 20% to 85% by weight, more preferably in the range of 30% to 80% by weight, most preferably in the range of 20% to 60% by weight and most preferably in the range of 30% to 50% by weight based on the total composition. Furthermore, it can be provided that the further matrix material is a hole-transporting matrix material according to at least one of the formulas (7), (8), (9) or (10) and the hole-transporting matrix material has a mass fraction in the range from 10% by weight to 95% by weight %, preferably in the range from 15% to 90% by weight, more preferably in the range from 15% to 80% by weight, even more preferably in the range from 20% to 70% by weight % by weight, very particularly preferably in the range of 40% by weight to 80% by weight and most preferably in the range of 50% to 70% by weight of the total composition. Furthermore, it can be provided that the further matrix material is an electron-transporting matrix material according to at least one of the formulas (11), (12), (13), (14), (15), (16), (17) or (18) and the electron-transporting matrix material has a mass fraction in the range from 10% by weight to 95% by weight, preferably in the range from 15% by weight to 90% by weight, more preferably in the range from 15% by weight to 80% by weight. -%, even more preferably in the range from 20% to 70% by weight, very particularly preferably in the range from 40% to 80% by weight and most preferably in the range from 50% by weight to 70% by weight, based on the total composition. In addition, it can be provided that the composition consists exclusively of the formula (1) or the preferred embodiments thereof set out above and one of the other matrix materials mentioned, preferably compounds according to at least one of the formulas (7), (8), (9) or (10 ) consists. Furthermore, it can be provided that the composition consists exclusively of the formula (1) or the preferred embodiments thereof set out above and one of the other matrix materials mentioned, preferably compounds according to at least one of the formulas (11), (12), (13), (14) , (15), (16), (17) or (18). Furthermore, it can be provided that the composition consists exclusively of the formula (1) or the preferred embodiments thereof set out above and one of the other matrix materials mentioned, preferably compounds according to at least one of the formulas (7), (8), (9), (10) , (11), (12), (13), (14), (15), (16), (17) or (18). Particularly suitable phosphorescent compounds (=triplet emitters) are compounds which, when suitably excited, emit light, preferably in the visible range, and also 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 included, in particular a metal with this atomic number. The phosphorescence emitters used are preferably compounds which contain copper, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver, gold or europium, in particular compounds which contain iridium or platinum. Examples of the emitters described above can be found in 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 2010/102609, WO 2011/ WO02011/ 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 127018/61 015815, WO 2016/124304, WO 2017/032439 and WO 2018/011186. In general, all phosphorescent complexes are suitable as are used according to the prior art for phosphorescent electroluminescent devices and as are known to the person skilled in the field of organic electroluminescence, and the person skilled in the art can use further phosphorescent complexes without any inventive activity. Examples of phosphorescent dopants are listed in the table below. The compounds according to the invention are also particularly suitable as matrix materials for phosphorescent emitters in organic electroluminescent devices, such as are used, for. as described in WO 98/24271, US 2011/0248247 and US 2012/0223633. In these multicolored display components, an additional blue emission layer is vapor-deposited over the entire surface of all pixels, including those with a color other than blue. In a further embodiment of the invention, the organic electroluminescent device according to the invention contains no separate hole injection layer and/or hole transport layer and/or hole blocking layer and/or electron transport layer, ie the emitting layer is directly adjacent to the hole injection layer or the anode and/or the emitting layer is directly adjacent to the electron transport layer or the electron injection layer or the cathode, as described for example in WO 2005/053051. It is also possible to use a metal to use 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, such as. B. described in WO 2009/030981. In the further layers of the organic electroluminescent device according to the invention it is possible to use all the materials which are customarily used in accordance with the prior art. The person skilled in the art can therefore use all materials known for organic electroluminescent devices in combination with the compounds according to the invention of the formula (1) or the preferred embodiments described above without any inventive step. Also preferred is an organic electroluminescence device, characterized in that one or more layers are coated using a sublimation process. The materials are vapour-deposited 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 for the initial pressure to be even lower, for example less than 10 ^-7 mbar. An organic electroluminescent device is also preferred, characterized in that one or more layers are coated using the OVPD (organic vapor phase deposition) method or with the aid of carrier gas sublimation. The materials are applied 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. Also preferred is an organic electroluminescent device, characterized in that one or more layers of solution, such as. B. by spin coating, or with any printing method, such as. B. screen printing, flexographic printing, offset printing, LITI (Light Induced Thermal Imaging, thermal transfer printing), ink-jet printing (ink jet printing) or nozzle printing. For this are soluble compounds necessary, which are obtained, for example, by suitable substitution. Formulations for applying a compound according to formula (1) or its or its preferred embodiments outlined above are new A further subject of the present invention is therefore a formulation containing at least one solvent and a compound according to formula (1) or its preferred embodiments outlined above. Furthermore, a formulation containing at least one solvent and a compound of the formula (1) or the preferred embodiments thereof set out above and a compound of at least one of the formulas (7), (8), (9) or (10) is a subject of the present invention . Furthermore, a formulation containing at least one solvent and a compound of the formula (1) or the preferred embodiments thereof set out above and a compound of at least one of the formulas (11), (12), (13), (14), (15) , (16), (17) or (18) subject of the present invention. Furthermore, it can be provided that the formulations contain at least one solvent and a compound according to formula (1) or the preferred embodiments thereof set out above and a compound according to at least one of the formulas (7), (8), (9), (10) (11 ), (12), (13), (14), (15), (16), (17) or (18). Hybrid processes are also possible, in which, for example, one or more layers are applied from solution and one or more further layers are vapor-deposited. These methods are generally known to the person skilled in the art and can be applied to organic electroluminescent devices containing the compounds according to the invention without any inventive step. The compounds according to the invention and the organic electroluminescent devices according to the invention are distinguished in particular by an improved service life compared to the prior art. The other electronic properties of the electroluminescent devices, such as efficiency or operating voltage, remain at least as good. In a further variant, the compounds according to the invention and the organic electroluminescent devices according to the invention are distinguished, compared with the prior art, in particular by improved efficiency and/or operating voltage and a longer service life. The electronic devices according to the invention, in particular organic electroluminescent devices, are distinguished by one or more of the following surprising advantages over the prior art: 1. Electronic devices, in particular organic electroluminescent devices containing compounds of the formula (1) or the preferred embodiments described above and below , especially as a matrix material or as hole-conducting materials, have a very good service life. In this case, these connections bring about, in particular, a low roll-off, ie a low drop in the power efficiency of the device at high luminance levels. 2. Electronic devices, in particular organic electroluminescent devices containing compounds of the formula (1) or the preferred embodiments described above and below as hole-conducting materials and/or matrix materials, have excellent efficiency. In this connection, compounds according to the invention of the formula (1) or the preferred embodiments described above and below bring about a low operating voltage when used in electronic devices. 3. The compounds according to the invention of the formula (1) or the preferred embodiments described above and below exhibit very high stability and durability. 4. With compounds of the formula (1) or the preferred embodiments described above and below, in electronic devices, in particular organic electroluminescent devices, the formation of optical loss channels can be avoided. As a result, these devices are characterized by a high PL and thus high EL efficiency of emitters and excellent energy transfer from the matrices to dopants. 5. Compounds of the formula (1) or the preferred embodiments described above and below exhibit excellent glass film formation. 6. Compounds of the formula (1) or the preferred embodiments described above and below form very good films from solutions. 7. The compounds of the formula (1) or the preferred embodiments described above and below have a low triplet level T1, which can be, for example, in the range from −2.22 eV to −2.9 eV. These advantages mentioned above do not go hand in hand with an excessively high deterioration in the other electronic properties. It should be noted that variations of the embodiments described in the present invention are within the scope of this invention. Each feature disclosed in the present invention may, unless explicitly excluded, be substituted with alternative features serving the same, equivalent or similar purpose. Thus, unless otherwise stated, each feature disclosed in the present invention is to be considered as an example of a generic series or as an equivalent or similar feature. All features of the present invention may be combined in any manner, unless certain features and/or steps are mutually exclusive. This applies in particular to preferred features of the present invention. Equally can Features of non-essential combinations are used separately (and not in combination). It should also be noted that many of the features, and particularly those of the preferred embodiments of the present invention, are inventive in their own right and are not to be considered merely part of the embodiments of the present invention. Independent protection may be sought for these features in addition to or as an alternative to any presently claimed invention. The teaching on technical action disclosed with the present invention can be abstracted and combined with other examples. The invention is explained in more detail by the examples below, without intending to limit it thereby. From the descriptions, the person skilled in the art can carry out the invention in the entire disclosed range and produce further compounds according to the invention without any inventive step and use these in electronic devices or apply the method according to the invention.

EXAMPLES Unless stated otherwise, the syntheses below are carried out under a protective gas atmosphere in dried solvents. The solvents and reagents can e.g. B. from Sigma-ALDRICH or ABCR. The corresponding CAS numbers are also given for the compounds known from the literature. Synthesis Examples a) Bromination A solution of 37 g (150 mmol) thieno[2',3':4,5]pyrrolo[3,2,1-jk]carbazole in chloroform (900 mL) is treated in portions at -10 °C in the dark with N -bromosuccinimide (26.6 g, 150 mmol) and stirred at this temperature for 2 h. The reaction is terminated by adding sodium sulfite solution and stirred at room temperature for a further 30 minutes. After phase separation, the organic phase is washed with water and the aqueous phase is extracted with dichloromethane. The combined organic phases are dried over sodium sulfate and concentrated in vacuo. The residue is dissolved in toluene and filtered through silica gel. The crude product is then recrystallized from toluene/heptane. Yield: 34 g (106 mmol), 70% of theory. Th., colorless solid. Analogously, the following connections are made: b) Suzuki reaction 51.4 g (150 mmol) of compound a, 50 g (160 mmol) of N-phenylcarbazole-3-boronic acid and 36 g (340 mmol) of sodium carbonate are suspended in 1000 mL of ethylene glycol dimethyl ether and 280 mL of water. 1.8 g (1.5 mmol) of tetrakis(triphenylphosphine)- palladium(0) is added and the reaction mixture is refluxed for 16 h. After cooling, the organic phase is separated off, filtered through silica gel, washed three times with 200 mL water and then evaporated to dryness. The residue is extracted hot with toluene and recrystallized from toluene/n-heptane and finally sublimated under high vacuum. The yield is 51 g (104 mmol), corresponding to 67% of theory. Analogously, the following connections are made:



c) Copper-catalyzed condensation Under protective gas and without solvent, 10.6 g (44 mmol) 3,4-dibromothiophene, 9-phenyl-3,3'-bi-9H-carbazole 18 g (40 mmol), 6 g (44 mmol) K2CO3 and 500 mg (2 mmol) CuSO4-5H2O stirred in a reaction vessel. equipped with a stir bar and purged three times with argon. The reaction mixture is stirred under reflux (250°C) for 24 h. After cooling, the mixture is treated with 100 ml of dichloromethane and 100 ml of water and the organic phase is separated, dried over MgSO4 and filtered and the solvent is removed in vacuo. The residue is purified by column chromatography over silica gel (mobile phase: DCM/heptane (1:3). The yield is 7 g (12.5 mmol), corresponding to 48% of theory. The following connections can be made analogously:

d) CH activated cyclization In a round-bottomed flask, 20.8 g (63.7 mmol) of compound b, 17.3 g (126 mmol) of K2CO3, 1.8 g (3.21 mmol) of (NHC)Pd(allyl)Cl are added and then degassed and then filled with argent. 200 ml of degassed dimethylacetamide with a water content of less than 1000 ppm are added under an argon atmosphere. The mixture is heated to 130°C for 24 hours under an argon countercurrent and stirred until complete. After cooling, the mixture is treated with 100 ml of dichloromethane and 100 ml of water and the organic phase is separated, dried over MgSO4 and filtered and the solvent is removed in vacuo. The residue is purified by column chromatography over silica gel (mobile phase: DCM/heptane (1:3). The residue is extracted hot with toluene and recrystallized from toluene/n-heptane and finally sublimed under high vacuum. The yield is 10.5 (21. 9 mmol) of the mixture A+B, corresponding to 60% of theory. After column chromatography and subsequent work-up, 22% A and 38% B are obtained. The following compounds can be prepared analogously:

Production of the Electroluminescent Devices The use of the materials according to the invention in electroluminescent devices is presented in the following examples E1 to E20 (see Table 1). Pretreatment for Examples E1-E20: Glass flakes coated with structured ITO (indium tin oxide) with a thickness of 50 nm are first treated with an oxygen plasma, followed by an argon plasma, before the coating. These plasma-treated glass flakes form the substrates on which the OLEDs are applied. In principle, the electroluminescence devices have the following layer structure: substrate/hole injection layer (HIL)/hole transport layer (HTL)/electron blocking layer (EBL)/emission layer (EML)/optional hole blocking layer (HBL)/electron transport layer (ETL)/optional electron injection layer (EIL) and finally one Cathode. The cathode is formed by a 100 nm thick aluminum layer. The precise structure of the OLEDs can be found in Table 1. The materials required to fabricate the electroluminescent devices are shown in Table 2. The data of the electroluminescent devices are listed in Table 3. All materials are thermally evaporated in a vacuum chamber. In this case, the emission layer always consists of at least one matrix material (host material, host material), at least within the meaning of the invention two matrix materials, and an emitting dopant (dopant, emitter), which is added to the matrix material or matrix materials by co-evaporation in a specific volume fraction. A specification such as 2b:BisC1:TEG1 (45%:45%:10%) means that the material 2b accounts for 45% by volume, BisC1 for 45% and TEG1 for 10% in the layer present. Analogously, the electron transport layer can also consist of a mixture of two materials. The electroluminescent devices are characterized in a standard way. For this purpose, the electroluminescence spectra, the current efficiency (SE, measured in cd/A) and the external quantum efficiency (EQE, measured in %) are determined as a function of the luminance, calculated from current-voltage-luminance characteristics assuming a Lambertian radiation characteristic, and the lifetime . The electroluminescence spectra are determined at a luminance of 1000 cd/m² and the CIE 1931 x and y color coordinates are calculated from this. The specification U1000 in Table 18 describes the voltage required for a luminance of 1000 cd/m². SE1000 and EQE1000 denote the current efficiency and external quantum efficiency, respectively, achieved at 1000cd/m².

Use of Mixtures According to the Invention in Electroluminescent Devices The material combinations according to the invention can be used in the emission layer in phosphorescent OLEDs. The compounds 2b and 9b according to the invention are used as green matrix material in the emission layer in examples E1 to E2, and 10b and 18b are used as red matrix material in the emission layer in examples E16 to E17. The combinations according to the invention of compound BisC1 with corresponding compound b, 2b and 9b are used as matrix material in the emission layer in examples E3 to E5. Further combinations according to the invention of the compounds 24a and 2dB with the compounds Tz1 to Tz8 are used as matrix material in the emission layer in Examples E6 to E15. A further combination according to the invention of the compounds 18b with the compound BisC2 is used in example E18 as the red matrix material in the emission layer. In example E19, compound 9b according to the invention is used as electron blocking material in the EBL. In example E20, compound 28b according to the invention is used as hole transport material. Table 1: Structure of the electroluminescent devices

Table 2 Structural formulas of the materials for the electroluminescent devices

Table 3: Performance data of the electroluminescent devices

Claims

Claims 1. A compound comprising at least one structure of formula (1), preferably a compound according to formula (1), where the following applies to the symbols and indices used: T stands for a heteroaromatic 5-membered ring with a sulfur atom which is fused to the azole ring via two adjacent and interconnected carbon atoms and which can be substituted by one or more groups R ³ ; L represents a linking group, which is preferably selected from a bond or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can be substituted with one or more radicals R ² , particularly preferably a bond; X is N, CR or C if a group L, Y ¹ or Y ² is attached thereto, with the proviso that no more than two of the groups X in a cycle are N, preferably X is C or CR; X ¹ is N, CR ¹ or C if the group L is attached thereto, with the proviso that no more than two of the groups X in a cycle are N, preferably X ¹ is CR ¹ ; Y represents NAr, NL, O, S, C(R ² )2, C(L)(R ² ), where NL means that the group L binds to the nitrogen atom of the group NL, and C(L)(R ² ) means that the group L binds to the C atom of the group C(L)(R ² ); Y ¹ represents a bond, NL, NR ² , NAr', O, S, C(R ² )2, where NL means that the group L binds to the nitrogen atom of the group NL; r is 0 or 1, where r=0 means that the group Y ¹ is absent; Y ² represents a bond, NL, NR ² , NAr', O, S, C(R ² )2, where NL means that the group L binds to the nitrogen atom of the group NL; s is 0 or 1, where s=0 means that the group Y ² is absent; Ar is identical or different on each occurrence and is an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can be substituted by one or more R ² radicals; R is the same or different on each occurrence H, D, F, Cl, Br, I, N(R ⁴ )2, N(Ar')2, CN, NO2, OR ⁴ , SR ⁴ , COOR ⁴ , C(= O)N(R4 ) ² , Si(R4 ) ³ , B(OR4 ) ² , C(=O)R4 , P(=O)( ^R4 ) ² , S(=O) ^R4 , S (= O) 2R ⁴ , OSO2R ⁴ , a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, the Each alkyl, alkenyl or alkynyl group can be substituted by one or more R ⁴ radicals and one or more non-adjacent CH 2 groups are replaced by Si(R ⁴ ) 2 , C═O, NR ⁴ , O, S or CONR ⁴ can be, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, preferably with 5 up to 40 aromatic ring atoms, each of which can be substituted by one or more radicals R ⁴ ; two radicals R or one radical R with one radical R ² , R ³ can also form an aliphatic or heteroaliphatic ring system with one another, the radicals R preferably not forming such a ring system; R ¹ is identical or different on each occurrence H, D, F, Cl, Br, I, N(R ⁴ )2, N(Ar')2, CN, NO2, OR ⁴ , SR ⁴ , COOR ⁴ , C( =O)N(R4 ) ² , Si(R4 ) ³ , B(OR4 ) ² , C(=O)R4 , P(=O)( ^R4 ) ² , S(=O) ^R4 , S(=O)2R ⁴ , OSO2R ⁴ , a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group can each be substituted with one or more radicals R ⁴ and one or more non-adjacent CH 2 groups can be replaced by Si(R ⁴ ) 2 , C=O, NR ⁴ , O, S or CONR ⁴ can be replaced, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, preferably with 5 to 40 aromatic ring atoms, which can each be substituted by one or more radicals R ⁴ ; two radicals R ¹ or one radical R ¹ with one radical R ² can also form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system with one another, the radicals R ¹ preferably not forming such a ring system; R ² is the same or different on each occurrence, H, D, F, Cl, Br, I, N(R ⁴ )2, N(Ar')2, CN, NO2, OR ⁴ , SR ⁴ , COOR ⁴ , C( =O)N(R4 ) ² , Si(R4 ) ³ , B(OR4 ) ² , C(=O)R4 , P(=O)( ^R4 ) ² , S(=O) ^R4 , S(=O)2R ⁴ , OSO2R ⁴ , a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group can each be substituted with one or more radicals R ⁴ and one or more non-adjacent CH 2 groups can be replaced by Si(R ⁴ ) 2 , C=O, NR ⁴ , O, S or CONR ⁴ may be replaced, or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, preferably having 5 to 40 aromatic ring atoms, each of which may be substituted by one or more R ⁴ radicals; two radicals R ² or one radical R ² with one radical R, R ¹ , R ³ can also form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system with one another, the radicals R ² preferably not forming such a ring system; R ³ is identical or different on each occurrence H, D, F, Cl, Br, I, N(R ⁴ )2, N(Ar')2, CN, NO2, OR ⁴ , SR ⁴ , COOR ⁴ , C( =O)N(R4 ) ² , Si(R4 ) ³ , B(OR4 ) ² , C(=O)R4 , P(=O)( ^R4 ) ² , S(=O) ^R4 , S(=O)2R ⁴ , OSO2R ⁴ , a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group can each be substituted with one or more radicals R ⁴ and one or more non-adjacent CH 2 groups can be replaced by Si(R ⁴ ) 2 , C=O, NR ⁴ , O, S or CONR ⁴ can be replaced, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, preferably with 5 to 40 aromatic ring atoms, which can each be substituted by one or more radicals R ⁴ ; two radicals R ³ or one radical R ³ with one radical R, R ² can also form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system with one another, the radicals R ³ preferably not forming such a ring system; Ar' is identical or different on each occurrence, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can be substituted by one or more R ⁴ radicals; R ⁴ is the same or different on each occurrence: H, D, F, Cl, Br, I, N(R ⁵ )2, CN, NO2, OR ⁵ , SR ⁵ , Si(R ⁵ )3, B(OR ⁵ ) 2, C(=O)R ⁵ , P(=O)(R ⁵ )2, S(=O)R ⁵ , S(=O)2R ⁵ , OSO2R ⁵ , a straight-chain alkyl group with 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group can each be substituted by one or more radicals R ⁵ , where one or more non-adjacent CH2 groups are replaced by Si(R ⁵ )2, C= O, NR ⁵ , O, S or CONR ⁵ can be replaced, or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can each be substituted by one or more radicals R ⁵ ; two or more radicals R ⁴ together can form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system, preferably the radicals R ⁴ do not form such a ring system; R ⁵ is identical or different on each occurrence and is H, D, F or an aliphatic, aromatic or heteroaromatic organic radical, in particular a hydrocarbon radical, having 1 to 20 carbon atoms in which one or more H atoms have also been replaced by F could be; where the sum of r and s is 1 or 2, preferably 1. 2. A compound according to claim 1 comprising at least one structure of formulas (1a), (1b), (1c), (1d), (1e), (1f), (1g), (1h), (1i), ( 1j), (1k), (1l), (1m), (1n), (1o), (1p), (1q), (1r), (1s), (1t), (1u), (1v) , (1w), (1x), (1y), (1z) and (1za), preferably selected from the compounds of the formulas (1a), (1b), (1c), (1d), (1e), (1f ), (1g), (1h), (1i), (1j), (1k), (1l), (1m), (1n), (1o), (1p), (1q), (1r), (1s), (1t), (1u), (1v), (1w), (1x), (1y), (1z) and (1za),

where Y, Y ¹ , Y ² , X, X ¹ , r, s and R ³ are as defined in claim 1, j is 0, 1 or 2, preferably 0 or 1 and k is 0 or 1, where s + k = 0 or 1 and j + s = 0, 1 or 2. 3. A compound according to claim 1 or 2, comprising at least one structure of the formulas (2a), (2b), (2c), (2d), (2e), (2f), (2g), (2h), (2i) , (2j), (2k), (2l), (2m), (2n), (2o), (2p), (2q), (2r), (2s), (2t), (2u), ( 2v), (2w), (2x), (2y), (2z) and (2za), preferably selected from the compounds of the formulas (2a), (2b), (2c), (2d), (2e ), (2f), (2g), (2h), (2i), (2j), (2k), (2l), (2m), (2n), (2o), (2p), (2q), (2r), (2s), (2t), (2u), (2v), (2w), (2x), (2y), (2z) and (2za),

where L, Y, R, R ¹ and R ³ have the meanings mentioned in claim 1, the index k is 0 or 1, the index j is 0, 1 or 2, preferably 0 or 1, the index n is 0, 1, 2 or 3, preferably 0, 1 or 2 and very preferably 0 or 1 and the index m is 0, 1,

2,

3 or 4, preferably 0, 1 or 2 and most preferably 0 or 1.

4. A compound according to one or more of claims 1 to 3, comprising at least one structure of the formulas (3a), (3b), (3c), (3d), (3e), (3f), (3g), (3h) , (3i), (3j), (3k), (3l), (3m), (3n), (3o), (3p), (3q) and (3r), preferably selected from the compounds of the formulas (3a ), (3b), (3c), (3d), (3e), (3f), (3g), (3h), (3i), (3j), (3k), (3l), (3m), (3n), (3o), (3p), (3q) and (3r),

where L, Y, R, R ¹ and R ³ are as defined in claim 1, the index k is 0 or 1, the index n is 0, 1, 2 or 3, preferably 0, 1 or 2 and very preferably 0 or is 1 and the index m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2 and most preferably 0 or 1.

5. A compound according to one or more of claims 1 to 4, comprising at least one structure of the formulas (4a), (4b), (4c), (4d), (4e), (4f), (4g), (4h) , (4i), (4j), (4k), (4l), (4m), (4n), (4o), (4p), (4q) and (4r), preferably selected from the compounds of the formulas (4a ), (4b), (4c), (4d), (4e), (4f), (4g), (4h), (4i), (4j), (4k), (4l), (4m), (4n), (4o), (4p), (4q) and (4r), where L, Y, R, R ¹ and R ³ have the meanings mentioned in claim 1, the index k is 0 or 1, the index j is 0, 1 or 2, preferably 0 or 1, the index n is 0, 1, is 2 or 3, preferably 0, 1 or 2 and more preferably 0 or 1 and the index m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2 and most preferably 0 or 1

6. A compound according to one or more of claims 1 to 5, comprising at least one structure of the formulas (5a), (5b), (5c), (5d), (5e), (5f), (5g), (5h) and (5i), preferably selected from the compounds of the formulas (5a), (5b), (5c), (5d), (5e), (5f), (5g), (5h) and (5i),

where L, Y, R, R ¹ and R ³ have the meanings mentioned in claim 1, the index k is 0 or 1, the index j is 0, 1 or 2, preferably 0 or 1, the index n is 0, 1, is 2 or 3, preferably 0, 1 or 2 and more preferably 0 or 1 and the index m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2 and most preferably 0 or 1.

7. A compound according to one or more of claims 1 to 6, comprising at least one structure of the formulas (6a), (6b), (6c), (6d), (6e), (6f), (6g) and (6h) , preferably selected from the compounds of the formulas (6a), (6b), (6c), (6d), (6e), (6f), (6g) and (6h),

8. A compound according to one or more of claims 1 to 7, characterized in that L is a bond or represents a group selected from the formulas (L ¹ -1) to (L ¹ -16),

where the dashed bonds mark the attachment positions, Y ³ is the same or different on each occurrence, preferably O, S, NAr', NR ² , preferably O or S; the subscript k is 0 or 1, the subscript l is 0, 1 or 2, the subscript j is independently 0, 1, 2 or 3 for each occurrence; the subscript h is independently 0, 1, 2, 3 or 4 on each occurrence; the subscript g is 0, 1, 2, 3, 4 or 5; and the symbol R ² is as defined in claim 1, where L is preferably a bond or an aromatic ring system having 5 to 40 aromatic ring atoms which does not include any heteroatoms

9. A compound according to one or more of claims 1 to 8, characterized in that L is a bond and Y is selected from NAr, O, S, preferably Y is NAr.

10. A compound as claimed in one or more of claims 1 to 9, characterized in that R, R ¹ , R ² and/or R ³ 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-75 and/or the group Ar, identical or different on each occurrence, is selected from the groups of the following formulas Ar-1 to Ar-75

where R ⁴ has the meanings given above, the dashed bond represents the bond to the corresponding group and the following also applies: Ar ¹ is identical or different on each occurrence, a bivalent aromatic or heteroaromatic ring system having 6 to 18 aromatic ring atoms, which each may be substituted with one or more R ⁴ groups; A is, identically or differently, on each occurrence C(R ⁴ )2, NR ⁴ , O 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 bonded directly to the corresponding radical; q is 0 or 1, where q = 0 means that no group A is bonded to this position and radicals R ⁴ are bonded to the corresponding carbon atoms instead, 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 -75), 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.

11. A process for the preparation of a compound according to one or more of claims 1 to 14, characterized in that a thiofuran compound is reacted by means of a coupling reaction with an aromatic or heteroaromatic nitrogen compound.

12. Composition containing at least one compound according to one or more of claims 1 to 10 and at least one further matrix material, wherein the further matrix material is selected from compounds according to one of the formulas (7), (8), (9) or (10) , where the following applies to the symbols and indices used: R ⁶ is identical or different on each occurrence, H, D, F, Cl, Br, I, N(R ⁷ )2, N(Ar″)2, CN, NO2, OR ⁷ , SR ⁷ , COOR ⁷ , C(=O)N(R ⁷ )2, Si(R ⁷ )3, B(OR ⁷ )2, C(=O)R ⁷ , P(=O)(R ⁷ )2, S(=O)R ⁷ , S(=O)2R ⁷ , OSO2R ⁷ , a straight-chain alkyl group with 1 to 20 carbon atoms or an alkenyl or alkynyl group with 2 to 20 carbon atoms or a branched or cyclic one Alkyl group with 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group can each be substituted with one or more radicals R ⁷ and where one or more non-adjacent CH 2 groups are replaced by Si(R ⁷ ) 2 , C=O , NR ⁷ , O, S or CONR ⁷ can be replaced, or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, preferably having 5 to 40 aromatic ring atoms, each of which can be substituted by one or more R ⁷ radicals; in this case, two radicals R ⁶ can also together form an aromatic, form a heteroaromatic, aliphatic or heteroaliphatic ring system, preferably the radicals R ⁶ do not form such a ring system; Ar'' is identical or different on each occurrence, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can be substituted by one or more R ⁷ radicals; A ¹ is C(R ⁷ )2, NR ⁷ , O or S; Ar ⁵ is the same or different on each occurrence and is an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms which may be substituted by one or more R ⁷ radicals; R ⁷ is the same or different on each occurrence: H, D, F, Cl, Br, I, N(R ⁸ )2, CN, NO2, OR ⁸ , SR ⁸ , Si(R ⁸ )3, B(OR ⁸ ) 2, C(=O)R ⁸ , P(=O)(R ⁸ )2, S(=O)R ⁸ , S(=O)2R ⁸ , OSO2R ⁸ , a straight-chain alkyl group with 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, it being possible for the alkyl, alkenyl or alkynyl group to be substituted in each case by one or more radicals R ⁸ , with one or more non-adjacent CH2 groups can be replaced by Si(R ⁸ )2, C═O, NR ⁸ , O, S or CONR ⁸ , or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, each substituted by one or several radicals R ⁸ can be substituted; two or more radicals R ⁷ together can form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system, preferably the radicals R ⁷ do not form such a ring system; R ⁸ is identical or different on each occurrence H, D, F or an aliphatic, aromatic or heteroaromatic organic radical, in particular a hydrocarbon radical, with 1 to 20 C atoms, in which one or more H atoms can also be replaced by F; s is the same or different on each occurrence and is 0, 1, 2, 3 or 4, preferably 0 or 1 and very preferably 0; t is the same or different on each occurrence and is 0, 1, 2 or 3, preferably 0 or 1 and very preferably 0; u is the same or different on each occurrence and is 0, 1 or 2, preferably 0 or 1 and very preferably 0.

13. Composition containing at least one compound according to one or more of claims 1 to 10 and at least one further matrix material, wherein the further matrix material is selected from compounds according to one of the formulas (11), (12), (13), (14) , (15), (16), (17) or (18),

where the following applies to the symbols and indices used: X ² represents N or CR ⁹ , with the proviso that no more than two of the groups X ² in a cycle represent N, preferably at least one X ² represents N; L ² represents a linking group, which is preferably selected from a bond or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can be substituted with one or more radicals R ⁹ , particularly preferably a bond; Ar ⁶ is the same or different on each occurrence and is an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may be substituted by one or more R ¹⁰ radicals; R ⁹ is identical or different on each occurrence H, D, F, Cl, Br, I, N(R ¹⁰ )2, N(Ar''')2, CN, NO2, OR ¹⁰ , SR ¹⁰ , COOR ¹⁰ , C(=O)N( ^R10 )2, Si( ^R10 )3, B( ^OR10 )2, C(=O) ^R10 , P(=O)( ^R10 )2, S(=O) R ¹⁰ , S(=O)2R ¹⁰ , OSO2R ¹⁰ , a straight-chain alkyl group with 1 to 20 carbon atoms or an alkenyl or alkynyl group with 2 to 20 carbon atoms or a branched or cyclic alkyl group with 3 to 20 carbon atoms , where the alkyl, alkenyl or alkynyl group can each be substituted by one or more radicals R ⁴ and where one or more non-adjacent CH 2 groups are substituted by Si(R ¹⁰ ) 2 , C═O, NR ¹⁰ , O, S or CONR ¹⁰ may be replaced, or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, preferably having 5 to 40 aromatic ring atoms, which can each be substituted by one or more radicals R ¹⁰ ; two radicals R ⁹ can also form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system with one another, the radicals R ⁹ preferably not forming such a ring system; Ar''' is identical or different on each occurrence, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which can be substituted by one or more radicals R ¹⁰ ; A ² is C(R ¹⁰ )2, NR ¹⁰ , O or S; R ¹⁰ is the same or different on each occurrence: H, D, F, Cl, Br, I, N(R ¹¹ )2, CN, NO2, OR ¹¹ , SR ¹¹ , Si(R ¹¹ )3, B(OR ¹¹ ) 2, C(=O)R ¹¹ , P(=O)(R ¹¹ )2, S(=O)R ¹¹ , S(=O)2R ¹¹ , OSO2R ¹¹ , a straight-chain alkyl group with 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, it being possible for the alkyl, alkenyl or alkynyl group to be substituted in each case with one or more radicals R ¹¹ , with one or more non-adjacent CH2 groups can be replaced by Si(R ¹¹ )2, C═O, NR ¹¹ , O, S or CONR ¹¹ , or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, each of which is substituted by one or several radicals R ¹¹ can be substituted; two or more radicals R ¹⁰ can together form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system, preferably the radicals R ¹⁰ do not form such a ring system; R ¹¹ is identical or different on each occurrence and is H, D, F or an aliphatic, aromatic or heteroaromatic organic radical, in particular a hydrocarbon radical, having 1 to 20 carbon atoms in which one or more H atoms have also been replaced by F could be; v is the same or different on each occurrence and is 0, 1, 2, 3 or 4, preferably 0 or 1 and very preferably 0; t is the same or different on each occurrence and is 0, 1, 2 or 3, preferably 0 or 1 and very preferably 0; x is the same or different on each occurrence and is 0, 1, 2, 3 or 4, preferably 0 or 1 and very preferably 0; z is the same or different on each occurrence and is 0, 1 or 2, preferably 0 or 1 and very preferably 0, the sum of x and 2z being at most 4, preferably at most 2.

14. The composition as claimed in claim 12 or 13, characterized in that the compound of claims 1 to 10 in the composition has a mass fraction in the range from 10% by weight to 95% by weight, preferably in the range from 15% by weight to 90% by weight, and more preferably ranging from 40% to 70% by weight, based on the total weight of the composition.

15. Composition according to any one of claims 12 to 14, characterized in that the compounds according to one of the formulas (7), (8), (9), (10), (11), (12), (13), ( 14), (15), (16), (17) or (18) in the composition a mass fraction in the range from 5% by weight to 90% by weight, preferably in the range from 10% by weight to 85% by weight %, more preferably in the range from 20% by weight to 85% by weight, even more preferably in the range from 30% by weight to 80% by weight, very particularly preferably in the range from 20% by weight to 60% by weight and most preferably in the range of 30% to 50% by weight of the total composition.

16. Formulation containing at least one compound according to one or more of claims 1 to 10 and / or at least one composition according to one or more of claims 12 to 15 and at least one other compound, wherein the other Compound is preferably selected from one or more solvents.

17. Use of a compound according to one or more of claims 1 to 10 and/or a composition according to one or more of claims 12 to 15 in an electronic device.

18. Electronic device containing at least one compound according to one or more of claims 1 to 10 and/or a composition according to one or more of claims 12 to 15, wherein the electronic device is preferably an electroluminescence device.

19. The electronic device as claimed in claim 18, which is an organic electroluminescence device, characterized in that the compound as claimed in one or more of claims 1 to 19 is present as matrix material in an emitting layer and/or in an electron transport layer and/or or in a hole blocking layer and/or in a hole transport layer and/or in an electron blocking layer, preferably as matrix material in an emitting layer and/or in a hole transport layer and/or in an electron blocking layer, particularly preferably as matrix material in an emitting layer.

20. Electronic device according to claim 19, characterized in that the compound according to one or more of claims 1 to 10 is used as matrix material for phosphorescent emitters in combination with a further matrix material, wherein the further matrix material is selected from compounds according to one of Formulas (7), (8), (9) or (10),

where the symbols A ¹ , Ar ⁵ and R ⁶ and the indices s, t and u have the meanings given in claim 12, and/or the further matrix material is selected from compounds according to one of the formulas (11), (12), (13), (14), (15), (16), (17) or (18),

Symbols X ² , L ² , A ² , Ar ⁶ and R ⁹ and the indices v, t, x and z have the meanings given in claim 13.