Patent Publication Number: US-2023157171-A1

Title: Cyclic compounds for organic electroluminescent devices

Description:
The present invention relates to cyclic compounds for use in electronic devices, especially in organic electroluminescent devices, and to electronic devices, especially organic electroluminescent devices comprising these heterocyclic compounds. 
     Emitting materials used in organic electroluminescent devices are frequently phosphorescent organometallic complexes or fluorescent compounds. There is generally still a need for improvement in electroluminescent devices. 
     WO 2010/104047 A1 and WO 2019/132506 A1 disclose polycyclic compounds that can be used in organic electroluminescent devices. There is no disclosure of compounds according to the present invention. In addition, antiaromatic properties of compounds are examined by Wang et al., in Nature Communications 8:1948. However, there is no description of the use of these compounds in organic electroluminescent devices by Wang et al. 
     In general terms, there is still a need for improvement in these heterocyclic compounds, for example for use as emitters, especially as fluorescent emitters, particularly in relation to lifetime and color purity, but also in relation to the efficiency and operating voltage of the device. 
     It is therefore an object of the present invention to provide compounds which are suitable for use in an organic electronic device, especially in an organic electroluminescent device, and which lead to good device properties when used in this device, and to provide the corresponding electronic device. 
     More particularly, the problem addressed by the present invention is that of providing compounds which lead to a high lifetime, good efficiency and low operating voltage. 
     In addition, the compounds should have excellent processibility, and the compounds should especially show good solubility. 
     A further problem addressed by the present invention can be considered that of providing compounds suitable for use in a phosphorescent or fluorescent electroluminescent devices, especially as emitter. More particularly, a problem addressed by the present invention is that of providing emitters suitable for red, green or blue electroluminescent devices. 
     In addition, the compounds, especially when they are used as emitters in organic electroluminescent devices, should lead to devices having excellent color purity. 
     A further problem addressed by the present invention can be considered that of providing compounds suitable for use in phosphorescent or fluorescent electroluminescent devices, especially as a matrix material. 
     More particularly, a problem addressed by the present invention is that of providing matrix materials suitable for red-, yellow- and blue-phosphorescing electroluminescent devices. 
     In addition, the compounds, especially when they are used as matrix materials, as hole transport materials or as electron transport materials in organic electroluminescent devices, should lead to devices having excellent color purity. 
     A further problem can be considered that of providing electronic devices having excellent performance very inexpensively and in constant quality. 
     Furthermore, it should be possible to use or adapt the electronic devices for many purposes. More particularly, the performance of the electronic devices should be maintained over a broad temperature range. 
     It has been found that, surprisingly, this object is achieved by particular compounds described in detail below that are of very good suitability for use in preferably electroluminescent devices and lead to organic electroluminescent devices that show very good properties, especially in relation to lifetime, color purity, efficiency and operating voltage. The present invention therefore provides these compounds and electronic devices, especially organic electroluminescent devices, comprising such compounds. 
     The present invention provides a compound comprising at least one structure of the formula (I), preferably a compound of the formula (I), 
     
       
         
         
             
             
         
       
     
     where the symbols and indices used are as follows:
         Z 1 , Z 2  is the same or different at each instance and is N or B;   W 1 , W 2 , W 3 , W 4  are the same or different at each instance and are CAr, X, or two adjacent W 1 , W 2 , W 3 , W 1  groups are Ar;   Y 1  is the same or different at each instance and is N(Ar), N(R), P(Ar), P(R), P(═O)Ar, P(═O)R, P(═S)Ar, P(═S)R, B(Ar), B(R), Al(Ar), Al(R), Ga(Ar), Ga(R), C═O, C(R) 2 , Si(R) 2 , C═NR, C═NAr, C═C(R) 2 , O, S, Se, S═O, or SO 2 , preferably N(Ar), N(R), B(Ar), B(R), P(═O)R, P(═O)Ar, C═O, C(R) 2 , Si(R) 2 , O, S, Se, S═O, or SO 2 , more preferably C═O, N(Ar) or B(Ar);   Y 2  is the same or different at each instance and is a bond, N(Ar), N(R), P(Ar), P(R), P(═O)Ar, P(═O)R, P(═S)Ar, P(═S)R, B(Ar), B(R), Al(Ar), Al(R), Ga(Ar), Ga(R), C═O, C(R) 2 , Si(R) 2 , C═NR, C═NAr, C═C(R) 2 , O, S, Se, S═O, or SO 2 , preferably a bond, N(Ar), N(R), B(Ar), B(R), P(═O)R, P(═O)Ar, C═O, C(R) 2 , Si(R) 2 , O, S, Se, S═O, or SO 2 , more preferably C═O, N(Ar) or B(Ar);   Ar is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted by one or more R radicals; the Ar group here may form a ring system with at least one Ar group, R group or a further group;   X is the same or different at each instance and is N or CR, preferably CR, with the proviso that not more than two of the X, X 3  groups in one cycle are N;   X 1  is the same or different at each instance and is N, CR a  or CAr, preferably CR a , with the proviso that not more than two of the X 1 , X 2 , X 3  groups in one cycle are N;   X 2  is the same or different at each instance and is N, CR b  or CAr, preferably CR b , with the proviso that not more than two of the X 1 , X 2 , X 3  groups in one cycle are N;   X 3  is the same or different at each instance and is N, CR c , CAr or C if p is 1, preferably CR C , with the proviso that not more than two of the X, X 1 , X 2 , X 3  groups in one cycle are N;   p is the same or different and is 0 or 1, where p=1 if W 3 , W 4  are not Ar;   R, R a , R b , R c  is the same or different at each instance and is H, D, OH, F, Cl, Br, I, CN, NO 2 , N(Ar′) 2 , N(R 1 ) 2 , C(═O)OAr, C(═O)OR 1 , C(═O)N(Ar′) 2 , C(═O)N(R 1 ) 2 , C(Ar′) 3 , C(R 1 ) 3 , Si(Ar′) 3 , Si(R 1 ) 3 , B(Ar′) 2 , B(R 1 ) 2 , C(═O)Ar′, C(═O)R 1 , P(═O)(Ar′) 2 , P(═O)(R 1 ) 2 , P(Ar′) 2 , P(R 1 ) 2 , S(═O)Ar′, S(═O)R 1 , S(═O) 2 Ar′, S(═O) 2 R 1 , OSO 2 Ar′, OSO 2 R 1 , a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 carbon atoms or an alkenyl or alkynyl group having 2 to 40 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 carbon atoms, where the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group may in each case be substituted by one or more R 1  radicals, where one or more nonadjacent CH 2  groups may be replaced by R 1 C═CR 1 , C≡C, Si(R 1 ) 2 , C═O, C═S, C═Se, C═NR 1 , —C(═O)O—, —C(═O)NR 1 —, NR 1 , P(═O)(R 1 ), —O—, —S—, SO or SO 2 , or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted in each case by one or more R 1  radicals, or an aryloxy or heteroaryloxy group which has 5 to 60 aromatic ring atoms and may be substituted by one or more R 1  radicals; at the same time, two R, R a , R b , R c  radicals may also form a ring system together or with a further group;       Ar′ is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted by one or more R 1  radicals; at the same time, it is possible for two Ar′ radicals bonded to the same carbon atom, silicon atom, nitrogen atom, phosphorus atom or boron atom also to be joined together via a bridge by a single bond or a bridge selected from B(R 1 ), C(R 1 ) 2 , Si(R 1 ) 2 , C═O, C═NR 1 , C≡C(R 1 ) 2 , O, S, S═O, SO 2 , N(R 1 ), P(R 1 ) and P(═O)R 1 ;   R 1  is the same or different at each instance and is H, D, F, Cl, Br, I, CN, NO 2 , N(Ar″) 2 , N(R 2 ) 2 , C(═O)OAr″, C(═O)OR 2 , C(═O)Ar″, C(═O)R 2 , P(═O)(Ar″) 2 , P(Ar″) 2 , B(Ar″) 2 , B(R 2 ) 2 , C(Ar″) 3 , C(R 2 ) 3 , Si(Ar″) 3 , Si(R 2 ) 3 , a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 40 carbon atoms or an alkenyl group having 2 to 40 carbon atoms, each of which may be substituted by one or more R 2  radicals, where one or more nonadjacent CH 2  groups may be replaced by —R 2 C═CR 2 —, —C═C—, Si(R 2 ) 2 , C═O, C═S, C═Se, C═NR 2 , —C(═O)O—, —C(═O)NR 2 —, NR 2 , P(═O)(R 2 ), —O—, —S—, SO or SO 2  and where one or more hydrogen atoms may be replaced by D, F, Cl, Br, I, CN or NO 2 , or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms, each of which may be substituted by one or more R 2  radicals, or an aryloxy or heteroaryloxy group which has 5 to 60 aromatic ring atoms and may be substituted by one or more R 2  radicals, or an aralkyl or heteroaralkyl group which has 5 to 60 aromatic ring atoms and may be substituted by one or more R 2  radicals, or a combination of these systems; at the same time, two or more, preferably adjacent R 1  radicals together may form a ring system; at the same time, one or more R 1  radicals may form a ring system with a further part of the compound;   Ar″ is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 30 aromatic ring atoms and may be substituted by one or more R 2  radicals; at the same time, it is possible for two Ar″ radicals bonded to the same carbon atom, silicon atom, nitrogen atom, phosphorus atom or boron atom also to be joined together via a bridge by a single bond or a bridge selected from B(R 2 ), C(R 2 ) 2 , Si(R 2 ) 2 , C═O, C═NR 2 , C≡C(R 2 ) 2 , O, S, S═O, SO 2 , N(R), P(R 2 ) and P(═O)R 2 ;   R 2  is the same or different at each instance and is selected from the group consisting of H, D, F, CN, an aliphatic hydrocarbyl radical having 1 to 20 carbon atoms or an aromatic or heteroaromatic ring system which has 5 to 30 aromatic ring atoms and in which one or more hydrogen atoms may be replaced by D, F, Cl, Br, I or CN and which may be substituted by one or more alkyl groups each having 1 to 4 carbon atoms; at the same time, two or more, preferably adjacent substituents R 2  together may form a ring system.   

     In formula (I), p may be the same or different and may be 0 or 1, where p=1 if W 3 , W 4  are not Ar. Accordingly, p may only be 0 if W 3 , W 4  together form an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted by one or more R radicals. The aromatic or heteroaromatic ring system which is formed by the W 3 , W 4  groups and may be substituted by R groups binds to the Z 2  group in formula (I) if p=0. In addition, the W 3 , W 4  groups may be Ar if p=1. In this case, the W 3 , W 4  groups together form an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted by one or more R radicals, where the aromatic or heteroaromatic ring system binds to the Z 2  and Y 2  groups via two adjacent and mutually bonded carbon atoms in formula (I), such that a six ring is formed together with the Z 2  and Y 2  groups. If the W 1 , W 2  groups are Ar, the aromatic or heteroaromatic ring system binds to the Z 1  and Y 1  groups via two adjacent and mutually bonded carbon atoms in formula (I), such that a six ring is formed together with the Z 1  and Y 1  groups. 
     This is elucidated in detail hereinafter by the formulae (Ia), (Ib), (Ic) and (Id). The formulae (Ia) and (Ib) here illustrate the cases detailed above in which p=1, and the formula (Ic) illustrates the case that p=0. If the W 1 , W 2  groups together are Ar, formula (Id) is correspondingly applicable. 
     In formula (I), p may be the same or different and may be 0 or 1, where:
         when p=1, the formula (I) conforms to the formula (Ia) or (Ib);   when p=0, the formula (I) conforms to the formula (Ic):       

     
       
         
         
             
             
         
       
     
     In formula (I), the W 1 , W 2  groups together may be Ar. This results in formula (Id): 
     
       
         
         
             
             
         
       
     
     In formulae (Ia), (Ib), (Ic) and (Id), the symbols have the definition detailed above for formula (I). 
     An aryl group in the context of this invention contains 6 to 40 carbon atoms; a heteroaryl group in the context of this invention contains 2 to 40 carbon atoms and at least one heteroatom, with the proviso that the sum total 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 understood here to mean either a simple aromatic cycle, i.e. benzene, or a simple heteroaromatic cycle, for example pyridine, pyrimidine, thiophene, etc., or a fused (annelated) aryl or heteroaryl group, for example naphthalene, anthracene, phenanthrene, quinoline, isoquinoline, etc. Aromatics joined to one another by a single bond, for example biphenyl, by contrast, are not referred to as an aryl or heteroaryl group but as an aromatic ring system. 
     An electron-deficient heteroaryl group in the context of the present invention is a heteroaryl group having at least one heteroaromatic six-membered ring having at least one nitrogen atom. Further aromatic or heteroaromatic five-membered or six-membered rings may 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 in the context of this invention contains 6 to 60 carbon atoms in the ring system. A heteroaromatic ring system in the context of this invention contains 2 to 60 carbon atoms and at least one heteroatom in the ring system, with the proviso that the sum total 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 shall be understood to mean a system which does not necessarily contain only aryl or heteroaryl groups, but in which it is also possible for two or more aryl or heteroaryl groups to be joined by a non-aromatic unit, for example a carbon, nitrogen or oxygen atom. For example, systems such as fluorene, 9,9′-spirobifluorene, 9,9-diarylfluorene, triarylamine, diaryl ethers, stilbene, etc. shall also be regarded as aromatic ring systems in the context of this invention, and likewise systems in which two or more aryl groups are joined, for example, by a short alkyl group. Preferably, the aromatic ring system is selected from fluorene, 9,9′-spirobifluorene, 9,9-diarylamine or groups in which two or more aryl and/or heteroaryl groups are joined to one another by single bonds. 
     In the context of the present invention, an aliphatic hydrocarbyl radical or an alkyl group or an alkenyl or alkynyl group which may contain 1 to 20 carbon atoms and in which individual hydrogen atoms or CH 2  groups may also be substituted by the abovementioned groups is preferably understood to mean the methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl, neopentyl, cyclopentyl, n-hexyl, neohexyl, 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 radicals. An alkoxy group having 1 to 40 carbon atoms is preferably understood to mean 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 having 1 to 40 carbon atoms is understood to mean especially 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, alkyl, alkoxy or thioalkyl groups according to the present invention may be straight-chain, branched or cyclic, where one or more nonadjacent CH 2  groups may be replaced by the abovementioned groups; in addition, it is also possible for one or more hydrogen atoms to be replaced by D, F, Cl, Br, I, CN or NO 2 , preferably F, CI or CN, further preferably F or CN, especially preferably CN. 
     An aromatic or heteroaromatic ring system which has 5-60 or 5-40 aromatic ring atoms and may also be substituted in each case by the abovementioned radicals and which may be joined to the aromatic or heteroaromatic system via any desired positions is understood to mean especially 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, pyrazinimidazole, quinoxalinimidazole, 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-tetraazaperylene, pyrazine, phenazine, phenoxazine, phenothiazine, fluorubine, 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. 
     The wording that two or more radicals together may form a ring, in the context of the present description, should be understood to mean, inter alia, that the two radicals are joined to one another by a chemical bond with formal elimination of two hydrogen atoms. This is illustrated by the following scheme: 
     
       
         
         
             
             
         
       
     
     In addition, however, the abovementioned wording shall also be understood to mean that, if one of the two radicals is hydrogen, the second radical binds to the position to which the hydrogen atom was bonded, forming a ring. This will be illustrated by the following scheme: 
     
       
         
         
             
             
         
       
     
     In a preferred configuration, the compounds of the invention may comprise a structure of the formulae (IIa) to (IIk); more preferably, the compounds of the invention may be selected from the compounds of the formulae (IIa) to (IIk): 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     where W 1 , W 2 , Y 1 , Y 2 , Z 1 , Z 2 , X 1 , X 2  and X 3  have the definitions given above, especially for formula (I), and the further symbols and indices are as follows:
     X is the same or different at each instance and is N, CR or C if p is 1, preferably CR or C, with the proviso that not more than two X groups in one cycle are N;   Y 3  is the same or different at each instance and is O, S, N(Ar′), N(R), C═O, C(R) 2 , Si(R) 2 , C═NR, C═NAr, C≡C(R) 2 , B(Ar) or B(R), preferably C(R) 2 , O, S or N(Ar′);   p is 0 or 1.   

     In a further preferred embodiment, it may be the case that the compounds of the invention include a structure of the formulae (IIIa) to (IIIk), where the compounds of the invention may more preferably be selected from the compounds of the formulae (IIIa) to (IIIk) 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     where the symbols Y 1 , Y 2 , Z 1 , Z 2 , X 1 , X 2  and X 3  have the definitions given above, especially for formula (I), the symbols X, Y 3  and the index p have the definitions given above, especially for formula (IIa) to (IIk). 
     It may preferably be the case that, in formulae (I), (IIa) to (IIk) and/or (IIIa) to (IIIk), not more than four, preferably not more than two, X, X 1 , X 2  and X 3  groups are N; more preferably, all X, X 1 , X 2  and X 3  groups are CR, CR a , CR b , CR c  or C if the X and X 3  groups form a ring system via a bond. 
     In a further-preferred embodiment, it may be the case that the compounds of the invention include a structure of the formula (IV-1) to (IV-20), where the compounds of the invention may more preferably be selected from the compounds of the formulae (IV-1) to (IV-20) 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     where the symbols Y 1 , Y 2 , Z 1 , Z 2 , R, R a , R b  and R c  have the definitions given above, especially for formula (I), symbol Y 3  has the definition given above, especially for formula (IIa) to (IIk), the index I is 0, 1, 2, 3, 4 or 5, preferably 0, 1 or 2, and the index m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2, the index n is 0, 1, 2 or 3, preferably 0, 1 or 2, the index j is 0, 1 or 2, preferably 0 or 1, and the index k is 0 or 1. 
     Preference is given here to structures/compounds of the formulae (IV-1) to (1V-10) and particular preference to structures of the formulae (IV-1) to (IV-9). 
     The sum total of the indices j, l, m and n in structures/compounds of the formulae (IV-1) to (IV-20) is preferably not more than 8, especially preferably not more than 6 and more preferably not more than 4. 
     In addition, in formulae (I), (IIa) to (IIk), (IIIa) to (IIIk), (IV-1) to (IV-20) and/or in the preferred embodiments of these formulae set out hereinafter, inter alia, it may be the case that at least one, preferably two, of the Z 1  and Z 2  groups is/are N and at least one, preferably two, of the Y 1  and Y 2  groups is/are B(Ar), B(R), P(═O)Ar, P(═O)R, Al(Ar), Al(R), Ga(Ar), Ga(R), C═O, S═O or SO 2 , preferably C═O, B(Ar), B(R), P(═O)Ar, P(═O)R, C═O, S═O or SO 2 , more preferably C═O, B(R) or B(Ar). Configurations in which at least one of the Z 1  and Z 2  groups is/are N and at least one, preferably two, Y 1 , Y 2  group(s) is/are B(Ar), B(R), P(═O)Ar, P(═O)R, Al(Ar), Al(R), Ga(Ar), Ga(R), C═O, S═O or SO 2  may advantageously be used as emitter. 
     Moreover, in formulae (I), (IIa) to (IIk), (IIIa) to (IIIk), (IV-1) to (IV-20) and/or in the preferred embodiments of these formulae set out hereinafter, inter alia, it may be the case that at least one, preferably two, of the Z 1  and Z 2  groups is/are N and at least one, preferably two, of the Y 1  and Y 2  groups is/are N(Ar), N(R), P(Ar), P(R), O, S or Se, preferably N(Ar), N(R), O or S, more preferably N(Ar). 
     Embodiments in which at least one, preferably two, of the Z 1  and Z 2  groups is/are N and at least one, preferably two, of the Y 1 , Y 2  group(s) is/are N(Ar), N(R), P(Ar), P(R), O, S or Se may advantageously be used especially as hole conductor material. 
     In a further configuration, in formulae (I), (IIa) to (IIk), (IIIa) to (IIIk), (IV-1) to (IV-20) and/or in the preferred embodiments of these formulae set out hereinafter, inter alia, it may be the case that at least one, preferably two, of the Z 1  and Z 2  groups is/are B and at least one, preferably two, of the Y 1 , Y 2  groups is/are N(Ar), N(R), P(Ar), P(R), O, S or Se, preferably N(Ar), N(R), O or S, more preferably N(Ar). Configurations in which at least one of the Z 1  and Z 2  groups is B and at least one, preferably two, Y 1 , Y 2  group(s) is/are N(Ar), N(R), P(Ar), P(R), O, S or Se may advantageously be used as emitter. 
     In a further configuration, in formulae (I), (IIa) to (IIk), (IIIa) to (IIIk), (IV-1) to (IV-20) and/or in the preferred embodiments of these formulae set out hereinafter, inter alia, it may be the case that at least one, preferably two, of the Z 1  and Z 2  groups is/are B and at least one, preferably two, of the Y 1 , Y 2  groups is/are B(Ar), B(R), P(═O)Ar, P(═O)R, Al(Ar), Al(R), Ga(Ar), Ga(R), C═O, S═O or SO 2 , preferably C═O, B(Ar), B(R), P(═O)Ar, P(═O)R, C═O, S═O or SO 2 , more preferably C═O, B(R) or B(Ar). 
     Embodiments in which at least one, preferably two, of the Z 1  and Z 2  groups is/are B and at least one, preferably two, of the Y 1 , Y 2  group(s) is/are B(Ar), B(R), P(═O)Ar, P(═O)R, Al(Ar), Al(R), Ga(Ar), Ga(R), C═O, S═O or SO 2  may advantageously be used especially as electron transport material. 
     In addition, in formulae (IIa) to (IIk), (IIIa) to (IIIk), (IV-1) to (IV-20) and/or the preferred embodiments of these formulae detailed below, inter alia, it may be the case that the two Y 3  groups are the same. 
     Furthermore, in formulae (IIa) to (IIk), (IIIa) to (IIIk), (IV-1) to (IV-20) and/or the preferred embodiments of these formulae detailed below, inter alia, it may be the case that the two Y 3  groups are different. 
     More preferably, the compounds include at least one structure of the formulae (V-1) to (V-40); more preferably, the compounds are selected from compounds of the formulae (V-1) to (V-40): 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     where the symbols Z 1 , Z 2 , X, X 1  and X 2  have the definition given above, especially for formula (I), the symbol Y 3  has the definition given above, especially for formula (IIa) to (IIk), and Z 3 , Z 4  are the same or different at each instance and are N, B, P(═O) or Si(R), preferably N, B or P(═O), more preferably N or B. 
     Preference is given here to structures/compounds of the formulae (V-1) to (V-30), particular preference to structures of the formulae (V-2), (V-5) to (V-9), (V-12), (V-15) to (V-19), (V-22), (V-25) to (V-29). 
     It may further be the case that, in formulae (V-1) to (V-40), not more than four, preferably not more than two, X, X 1  and X 2  groups are N; more preferably, all X, X 1  and X 2  groups are CR, CR a , CR b  or C if a ring closure with an X group is formed by a bond. 
     More preferably, the compounds include at least one structure of the formulae (VI-1) to (VI-40), more preferably, the compounds are selected from compounds of the formulae (VI-1) to (VI-40): 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     where Z 1 , Z 2 , R, R a  and R b  have the definitions given above, especially for formula (I), the symbol Y 3  has the definition given above, especially for formula (IIa) to (IIk), Z 3 , Z 4  are the same or different at each instance and are N, B, P(═O) or Si(R), preferably N, B or P(═O), more preferably N or B, the index I is 0, 1, 2, 3, 4 or 5, preferably 0, 1 or 2, and the index m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2, and the index j is 0, 1 or 2, preferably 0 or 1. 
     Preference is given here to structures/compounds of the formulae (VI-1) to (VI-30), particular preference to structures/compounds of the formulae (VI-2), (VI-5) to (VI-9), (VI-12), (VI-15) to (VI-19), (VI-22), (VI-25) to (VI-29). 
     In addition, in formulae (V-1) to (V-20), (VI-1) to (VI-20) and/or the preferred embodiments of these formulae detailed below, inter alia, it may be the case that at least one, preferably two, of the Z 1  and Z 2  groups is/are N and at least one, preferably two, of the Z 3  and Z 4  groups is/are B. Configurations in which at least one, preferably two, of the Z 1  and Z 2  groups is/are N and at least one, preferably two, of the Z 3  and Z 4  groups is/are B may advantageously be used as emitter. 
     Moreover, in formulae (V-1) to (V-20), (VI-1) to (VI-20) and/or the preferred embodiments of these formulae detailed below, inter alia, it may be the case that at least one, preferably two, of the Z 1  and Z 2  groups is/are N and at least one, preferably two, of the Z 3  and Z 4  groups is/are N. 
     Embodiments in which many, preferably all, of the Z 1 , Z 2 , Z 3 , Z 4  groups are N can advantageously be used as hole conductor material in particular. 
     In a further configuration, in formulae (V-1) to (V-20), (VI-1) to (VI-20) and/or the preferred embodiments of these formulae detailed below, inter alia, it may be the case that at least one, preferably two, of the Z 1  and Z 2  groups is/are B and at least one, preferably two, of the Z 3  and Z 4  groups is/are N. Configurations in which at least one, preferably two, of the Z 1  and Z 2  groups is/are B and at least one, preferably two, of the Z 3  and Z 4  groups is/are N may advantageously be used as emitter. 
     In a further configuration, in formulae (V-1) to (V-20), (VI-1) to (VI-20) and/or the preferred embodiments of these formulae detailed below, inter alia, it may be the case that at least one, preferably two, of the Z 1  and Z 2  groups is/are B and at least one, preferably two, of the Z 3  and Z 4  groups is/are B. 
     Embodiments in which many, preferably all, of the Z 1 , Z 2 , Z 3 , Z 4  groups are B can advantageously be used as electron transport material in particular. 
     In a further configuration, in formulae (V-1) to (V-20), (VI-1) to (VI-20) and/or the preferred embodiments of these formulae detailed below inter alia, it may be the case that at least one, preferably two, of the Z 2 , Z 3  groups is/are N and at least one, preferably two, of the Z 4 , Z 5  groups is/are B. 
     In structures of the formulae (VI-1) to (VI-40), it may be the case that the sum total of the indices j, I and m is preferably not more than 8, especially preferably not more than 6 and more preferably not more than 4. 
     In a preferred development of the present invention, it may be the case that at least two R, R a , R b , R c  radicals together with the further groups to which the two R, R a , R b , R c  radicals bind form a fused ring, where the two R, R a , R b , R c  radicals form at least one structure of the formulae (RA-1) to (RA-12): 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     where R 1  has the definition set out above, the dotted bonds represent the sites of attachment via which the two R, R a , R b , R c  radicals bind, and the further symbols have the following definition:
     Y 4  is the same or different at each instance and is C(R 1 ) 2 , (R 1 ) 2 C—C(R 1 ) 2 , (R 1 )C≡C(R 1 ), NR 1 , NAr′, O or S, preferably C(R 1 ) 2 , (R 1 ) 2 C—C(R 1 ) 2 , (R 1 )C≡C(R 1 ), O or S;   R d  is the same or different at each instance and is F, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 carbon atoms or an alkenyl or alkynyl group having 2 to 40 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 carbon atoms, where the alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group may be substituted in each case by one or more R 2  radicals, where one or more nonadjacent CH 2  groups may be replaced by R 2 C═CR 2 , C≡C, Si(R 2 ) 2 , C═O, C═S, C═Se, C═NR 2 , —C(═O)O—, —C(═O)NR 2 —, NR 2 , P(═O)(R 1 ), —O—, —S—, SO or SO 2 , or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted in each case by one or more R 2  radicals, or an aryloxy or heteroaryloxy group which has 5 to 60 aromatic ring atoms and may be substituted by one or more R 2  radicals; at the same time, it is also possible for two R d  radicals together or one R d  radical together with an R 1  radical or together with a further group to form a ring system;   s is 0, 1, 2, 3, 4, 5 or 6, preferably 0, 1, 2, 3 or 4, more preferably 0, 1 or 2;   t is 0, 1, 2, 3, 4, 5, 6, 7 or 8, preferably 0, 1, 2, 3 or 4, more preferably 0, 1 or 2;   v is 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9, preferably 0, 1, 2, 3 or 4, more preferably 0, 1 or 2.   

     In a preferred embodiment of the invention, the at least two R, R a , R b , R c  radicals together with the further groups to which the two R, R a , R b , R c  radicals bind form a fused ring, where the two R, R a , R b , R c  radicals preferably form at least one of the structures of the formulae (RA-1a) to (RA-4f): 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     where the dotted bonds represent the sites of attachment via which the two R, R a , R b , R c  radicals bind, the index m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2, and the symbols R 1 , R 2 , R d  and the indices s and t have the definition given above, especially for formula (I) and/or formulae (RA-1) to (RA-12). 
     It may further be the case that the at least two R, R a , R b , R c  radicals that form structures of the formulae (RA-1) to (RA-12) and/or (RA-1a) to (RA-4f) and form a fused ring represent R, R a , R b , R c  radicals from adjacent X, X 1 , X 2 , X 3  groups, or represent R radicals that each bind to adjacent carbon atoms, where these carbon atoms are preferably connected via a bond. 
     In a further-preferred configuration, at least two R, R a , R b , R c  radicals together with the further groups to which the two R, R a , R b , R c  radicals bind form a fused ring, where the two R, R a , R b , R c  radicals form structures of the formula (RB): 
     
       
         
         
             
             
         
       
     
     where R 1  has the definition given above, especially for formula (I), the dotted bonds represent the bonding sites via which the two R, R a , R b , R c  radicals bind, the index m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2, and Y 5  is C(R 1 ) 2 , NR 1 , NAr, BR 1 , BAr, O or S, preferably C(R 1 ) 2 , NAr′ or O. 
     It may be the case here that the at least two R, R a , R b , R c  radicals that form structures of the formula (RB) and form a fused ring represent R, R a , R b , R c  radicals from adjacent X, X 1 , X 2 , X 3  groups, or represent R radicals that each bind to adjacent carbon atoms, where these carbon atoms are preferably connected to one another via a bond. 
     More preferably, the compounds include at least one structure of the formulae (VII-1) to (VII-50), more preferably, the compounds are selected from compounds of the formulae (VII-1) to (VII-50), where the compounds have at least one fused ring: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     where the symbols Y 1 , Y 2 , Z 1 , Z 2 , R, R a , R b  and R c  have the definitions given above, especially for formula (I), the symbol Y 3  has the definition given above, especially for formula (IIa) to (IIk), the symbol o represents the attachment sites of the fused ring, and the further symbols are defined as follows:
     l is 0, 1, 2, 3, 4 or 5, preferably 0, 1 or 2;   m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2;   n is 0, 1, 2 or 3, preferably 0, 1 or 2;   j is 0, 1 or 2, preferably 0 or 1;   k is 0 or 1.   

     Preferably, the fused ring, especially in formulae (VII-1) to (VII-50), is formed by at least two R, R a , R b , R c  radicals and the further groups to which the two R, R a , R b , R c  radicals bind, where the at least two R, R a , R b , R c  radicals form structures of the formulae (RA-1) to (RA-12), (RA-1a) to (RA-4f) and/or of the formula (RB), preferably structures of the formulae (RA-1) to (RA-12) and/or (RA-1a) to (RA-4f). 
     It may preferably be the case that the compounds have at least two fused rings, wherein at least one fused ring is formed by structures of the formulae (RA-1) to (RA-12) and/or (RA-1a) to (RA-4f) and a further ring is formed by structures of the formulae (RA-1) to (RA-12), (RA-1a) to (RA-4f) or (RB), where the compounds include at least one structure of the formulae (VIII-1) to (VIII-50), preferably where the compounds are selected from the compounds of the formulae (VIII-1) to (VIII-50): 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     where the symbols Y 1 , Y 2 , Z 1 , Z 2 , R, R a , R b  and R c  have the definitions given above, especially for formula (I), the symbol Y 3  has the definition given above, especially for formula (IIa) to (IIk), the symbol o represents the attachment sites, and the further symbols have the following definition:
     l is 0, 1, 2, 3, 4 or 5, preferably 0, 1 or 2;   m is 0, 1, 2, 3 or 4, preferably 0, 1 or 2;   n is 0, 1, 2 or 3, preferably 0, 1 or 2;   j is 0, 1 or 2, preferably 0 or 1; and   k is 0 or 1.   

     Especially in the formulae (VII-1) to (VII-50) and/or (VIII-1) to (VIII-50), the sum total of the indices k, j, l, m and n is preferably 0, 1, 2 or 3, more preferably 1 or 2. 
     It may be the case here that the formulae (VIII-1) to (VIII-50) have at least two fused rings, where the fused rings are the same and the moiety formed by two R, R a , R b , R c  radicals can be represented by at least one structure of the formulae (RA-1) to (RA-12) and/or (RA-1a) to (RA-4f). 
     It may further be the case that the formulae (VIII-1) to (VIII-50) have at least two fused rings, where the fused rings are different and the moiety formed by two R, R a , R b , R c  radicals can be represented in each case by at least one structure of the formulae (RA-1) to (RA-12) and/or (RA-1a) to (RA-4f). 
     It may additionally be the case that the formulae (VIII-1) to (VIII-50) have at least two fused rings, where the fused rings are different and one of the two fused rings has a moiety formed by two R, R a , R b , R c  radicals that can be represented by at least one of the structures of the formulae (RA-1) to (RA-12) and/or (RA-1a) to (RA-4f), and one of the two fused rings has a moiety formed by two R, R a , R b , R c  radicals that can be represented by one of the structures of the formula (RB). 
     It may additionally be the case that the substituents R, R a , R b , R c  and R d , R 1  and R 2  according to the above formulae do not form a fused aromatic or heteroaromatic ring system with the ring atoms of the ring system to which the substituents R, R a , R b , R c  and R d , R 1  and R 2  bind. This includes the formation of a fused aromatic or heteroaromatic ring system with possible substituents R 1  and R 2  that may be bonded to the R, R a , R b , R c , R d  and R 1  radicals. 
     When two radicals that may especially be selected from R, R a , R b , R c , R d , R 1  and/or R 2  form a ring system with one another, this ring system may be mono- or polycyclic, aliphatic, heteroaliphatic, aromatic or heteroaromatic. In this case, the radicals which together form a ring system may be adjacent, meaning that these radicals are bonded to the same carbon atom or to carbon atoms directly bonded to one another, or they may be further removed from one another. In addition, the ring systems provided with the substituents R, R a , R b , R c , R d , R 1  and/or R 2  may also be joined to one another via a bond, such that this can bring about a ring closure. In this case, each of the corresponding bonding sites has preferably been provided with a substituent R, R a , R b , R c , R d , R 1  and/or R 2 . 
     In a preferred configuration, a compound of the invention can be represented by at least one of the structures of formula (I), (IIa) to (IIk), (IIIa) to (IIIk), (IV-1) to (IV-20), (V-1) to (V-40), (VI-1) to (VI-40), (VII-1) to (VII-50) and/or (VIII-1) to (VIII-50). Preferably, compounds of the invention, preferably comprising structures of formula (I), (IIa) to (IIk), (IIIa) to (IIIk), (IV-1) to (IV-20), (V-1) to (V-40), (VI-1) to (VI-40), (VII-1) to (VII-50) and/or (VIII-1) to (VIII-50) have a molecular weight of not more than 5000 g/mol, preferably not more than 4000 g/mol, particularly preferably not more than 3000 g/mol, especially preferably not more than 2000 g/mol and most preferably not more than 1200 g/mol. 
     In addition, it is a feature of preferred compounds of the invention that they are sublimable. These compounds generally have a molar mass of less than about 1200 g/mol. 
     Preferred aromatic or heteroaromatic ring systems R, R a , R b , R c , R d , Ar′ and/or Ar are selected from phenyl, biphenyl, especially ortho-, meta- or para-biphenyl, terphenyl, especially ortho-, meta- or para-terphenyl or branched terphenyl, quaterphenyl, especially ortho-, meta- or para-quaterphenyl or branched quaterphenyl, fluorene which may be joined via the 1, 2, 3 or 4 position, spirobifluorene which may be joined via the 1, 2, 3 or 4 position, naphthalene, especially 1- or 2-bonded naphthalene, indole, benzofuran, benzothiophene, carbazole which may be joined via the 1, 2, 3, 4 or 9 position, dibenzofuran which may be joined via the 1, 2, 3 or 4 position, dibenzothiophene which may be joined via the 1, 2, 3 or 4 position, indenocarbazole, indolocarbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene or triphenylene, each of which may be substituted by one or more R 1  or R radicals. 
     It may preferably be the case that at least one substituent R, R a , R b , R c  is the same or different at each instance and is selected from the group consisting of H, D, a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 carbon atoms or an aromatic or heteroaromatic ring system selected from the groups of the following formulae Ar-1 to Ar-75, where the substituents R, R a , R b , R c  preferably either form a ring according to the structures of the formulae (RA-1) to (RA-12), (RA-1a) to (RA-4f) or (RB), or the substituent R, R a , R b , R c  is the same or different at each instance and is selected from the group consisting of H, D or an aromatic or heteroaromatic ring system selected from the groups of the following formulae Ar-1 to Ar-75, and/or the Ar′ group is the same or different at each instance and is selected from the groups of the following formulae Ar-1 to Ar-75: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     where R 1  is as defined above, the dotted bond represents the attachment site and, in addition:
     Ar 1  is the same or different at each instance and is a bivalent aromatic or heteroaromatic ring system which has 6 to 18 aromatic ring atoms and may be substituted in each case by one or more R 1  radicals;   A is the same or different at each instance and is C(R 1 ) 2 , NR 1 , O or S;   p is 0 or 1, where p=0 means that the Ar′ group is absent 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 A group is bonded at this position and R 1  radicals are bonded to the corresponding carbon atoms instead.   

     When the abovementioned groups for Ar have two or more A groups, possible options for these include all combinations from the definition of A. Preferred embodiments in that case are those in which one A group is NR 1  and the other A group is C(R 1 ) 2  or in which both A groups are NR 1  or in which both A groups are O. 
     When A is NR 1 , the substituent R 1  bonded to the nitrogen atom is preferably an aromatic or heteroaromatic ring system which has 5 to 24 aromatic ring atoms and may also be substituted by one or more R 2  radicals. In a particularly preferred embodiment, this R 1  substituent is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 6 to 24 aromatic ring atoms, especially 6 to 18 aromatic ring atoms, which does not have any fused aryl groups and which does not have any fused heteroaryl groups in which two or more aromatic or heteroaromatic 6-membered ring groups are fused directly to one another, and which may also be substituted in each case by one or more R 2  radicals. Preference is given to phenyl, biphenyl, terphenyl and quaterphenyl having bonding patterns as listed above for Ar-1 to Ar-11, where these structures, rather than by R 1 , may be substituted by one or more R 2  radicals, but are preferably unsubstituted. Preference is further given to triazine, pyrimidine and quinazoline as listed above for Ar-47 to Ar-50, Ar-57 and Ar-58, where these structures, rather than by R 1 , may be substituted by one or more R 2  radicals. 
     There follows a description of preferred substituents R, R a , R b , R c , and R d . 
     In a preferred embodiment of the invention, R, R a , R b , R c  are the same or different at each instance and are selected from the group consisting of H, D, F, CN, NO 2 , Si(R 1 ) 3 , B(OR 1 ) 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, where the alkyl group may be substituted in each case by one or more R 1  radicals, or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms, preferably 5 to 40 aromatic ring atoms, and may be substituted in each case by one or more R 1  radicals. 
     In a further-preferred embodiment of the invention, substituent R, R a , R b , R c  is the same or different at each instance 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, where the alkyl group may be substituted in each case by one or more R 1  radicals, or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms, preferably 5 to 40 aromatic ring atoms, and may be substituted in each case by one or more R 1  radicals. 
     It may further be the case that at least one substituent R, R a , R b , R c  is the same or different at each instance and is selected from the group consisting of H, D, an aromatic or heteroaromatic ring system which has 6 to 30 aromatic ring atoms and may be substituted by one or more R 1  radicals, or an N(Ar′) 2  group. In a further-preferred embodiment of the invention, the substituents R, R a , R b , R c  either form a ring according to the structures of the formulae (RA-1) to (RA-12), (RA-1a) to (RA-4f) or (RB), or R, R a , R b , R c  is the same or different at each instance and is selected from the group consisting of H, D, an aromatic or heteroaromatic ring system which has 6 to 30 aromatic ring atoms and may be substituted by one or more R 1  radicals, or an N(Ar′) 2  group. More preferably, substituent R, R a , R b , R c  is the same or different at each instance and is 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, more preferably having 6 to 13 aromatic ring atoms, each of which may be substituted by one or more R 1  radicals. 
     In a preferred embodiment of the invention, R d  is the same or different at each instance and is selected from the group consisting of 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 the alkyl group may be substituted in each case by one or more R 1  radicals, or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms, preferably 5 to 40 aromatic ring atoms, and may be substituted in each case by one or more R 1  radicals. 
     In a further-preferred embodiment of the invention, R d  is the same or different at each instance and is selected from the group consisting of a straight-chain alkyl group having 1 to 10 carbon atoms or a branched or cyclic alkyl group having 3 to 10 carbon atoms, where the alkyl group may be substituted in each case by one or more R 1  radicals, an aromatic or heteroaromatic ring system which has 6 to 30 aromatic ring atoms and may be substituted by one or more R 1  radicals. More preferably, R a  is the same or different at each instance and are selected from the group consisting of a straight-chain alkyl group having 1 to 5 carbon atoms or a branched or cyclic alkyl group having 3 to 5 carbon atoms, where the alkyl group may be substituted in each case by one or more R 1  radicals, or an aromatic or heteroaromatic ring system which has 6 to 24 aromatic ring atoms, preferably 6 to 18 aromatic ring atoms, more preferably 6 to 13 aromatic ring atoms, and may be substituted in each case by one or more R 1  radicals. 
     In a preferred embodiment of the invention, R d  is the same or different at each instance and is selected from the group consisting of a straight-chain alkyl group having 1 to 6 carbon atoms or a cyclic alkyl group having 3 to 6 carbon atoms, where the alkyl group may be substituted in each case by one or more R 1  radicals, or an aromatic or heteroaromatic ring system which has 6 to 24 aromatic ring atoms and may be substituted in each case by one or more R 1  radicals; at the same time, two R d  radicals together may also form a ring system. More preferably, R d  is the same or different at each instance and is selected from the group consisting of a straight-chain alkyl group 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 in each case by one or more R 1  radicals, but is preferably unsubstituted, or an aromatic ring system which has 6 to 12 aromatic ring atoms, especially 6 aromatic ring atoms, and may be substituted in each case by one or more preferably nonaromatic R 1  radicals, but is preferably unsubstituted; at the same time, two R d  radicals together may form a ring system. Most preferably, R d  is the same or different at each instance and is selected from the group consisting of a straight-chain alkyl group having 1, 2, 3 or 4 carbon atoms, or a branched alkyl group having 3 to 6 carbon atoms. Most preferably, R d  is a methyl group or is a phenyl group, where two phenyl groups together may form a ring system, preference being given to a methyl group over a phenyl group. 
     Preferred aromatic or heteroaromatic ring systems substituent R, R a , R b , R e , R d  or Ar or Ar′ are selected from phenyl, biphenyl, especially ortho-, meta- or para-biphenyl, terphenyl, especially ortho-, meta- or para-terphenyl or branched terphenyl, quaterphenyl, especially ortho-, meta- or para-quaterphenyl or branched quaterphenyl, fluorene which may be joined via the 1, 2, 3 or 4 position, spirobifluorene which may be joined via the 1, 2, 3 or 4 position, naphthalene, especially 1- or 2-bonded naphthalene, indole, benzofuran, benzothiophene, carbazole which may be joined via the 1, 2, 3 or 4 position, dibenzofuran which may be joined via the 1, 2, 3 or 4 position, dibenzothiophene which may be joined via the 1, 2, 3 or 4 position, indenocarbazole, indolocarbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene or triphenylene, each of which may be substituted by one or more R, R 1  or R 2  radicals. The structures Ar-1 to Ar-75 listed above are particularly preferred, preference being given to structures of the formulae (Ar-1), (Ar-2), (Ar-3), (Ar-12), (Ar-13), (Ar-14), (Ar-15), (Ar-16), (Ar-69), (Ar-70), (Ar-75), and particular preference to structures of the formulae (Ar-1), (Ar-2), (Ar-3), (Ar-12), (Ar-13), (Ar-14), (Ar-15), (Ar-16). With regard to the structures Ar-1 to Ar-75, it should be stated that these are shown with a substituent R 1 . In the case of the ring systems Ar, these substituents R 1  should be replaced by R, and in the case of R d , these substituents should be replaced by R 2 . 
     Further suitable R, R a , R b , R c  groups are groups of the formula —Ar 4 —N(Ar 2 )(Ar 3 ) where Ar 2 , Ar 3  and Ar 4  are the same or different at each instance and are an aromatic or heteroaromatic ring system which has 5 to 24 aromatic ring atoms and may be substituted in each case by one or more R 1  radicals. The total number of aromatic ring atoms in Ar 2 , Ar 3  and Ar 4  here is not more than 60 and preferably not more than 40. 
     In this case, Ar 4  and Ar 2  may also be bonded to one another and/or Ar 2  and Ar 3  to one another by a group selected from C(R 1 ) 2 , NR 1 , O and S. Preferably, Ar 4  and Ar 2  are joined to one another and Ar 2  and Ar 3  to one another in the respective ortho position to the bond to the nitrogen atom. In a further embodiment of the invention, none of the Ar 2 , Ar 3  and Ar 4  groups are bonded to one another. 
     Preferably, Ar 4  is an aromatic or heteroaromatic ring system which has 6 to 24 aromatic ring atoms, preferably 6 to 12 aromatic ring atoms, and may be substituted in each case by one or more R 1  radicals. More preferably, Ar 4  is 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 1  radicals, but are preferably unsubstituted. Most preferably, Ar 4  is an unsubstituted phenylene group. 
     Preferably, Ar 2  and Ar 3  are the same or different at each instance and are an aromatic or heteroaromatic ring system which has 6 to 24 aromatic ring atoms and may be substituted in each case by one or more R 1  radicals. Particularly preferred Ar 2  and Ar 3  groups are the same or different at each instance and are selected from the group consisting of benzene, ortho-, meta- or para-biphenyl, ortho-, meta- or para-terphenyl or branched terphenyl, ortho-, meta- or para-quaterphenyl 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. Most preferably, Ar 2  and Ar 3  are the same or different at each instance and are selected from the group consisting of benzene, biphenyl, especially ortho-, meta- or para-biphenyl, terphenyl, especially ortho-, meta- or para-terphenyl or branched terphenyl, quaterphenyl, especially ortho-, meta- or para-quaterphenyl or branched quaterphenyl, fluorene, especially 1-, 2-, 3- or 4-fluorene, or spirobifluorene, especially 1-, 2-, 3- or 4-spirobifluorene. 
     In a further preferred embodiment of the invention, R 1  is the same or different at each instance 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 alkyl group having 3 to 10 carbon atoms, where the alkyl group may be substituted in each case by one or more R 2  radicals, or an aromatic or heteroaromatic ring system which has 6 to 24 aromatic ring atoms and may be substituted in each case by one or more R 2  radicals. In a particularly preferred embodiment of the invention, R 1  is the same or different at each instance and is selected from the group consisting of H, a straight-chain alkyl group having 1 to 6 carbon atoms, especially 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 R 5  radicals, but is preferably unsubstituted, or an aromatic or heteroaromatic ring system which has 6 to 13 aromatic ring atoms and may be substituted in each case by one or more R 5  radicals, but is preferably unsubstituted. 
     In a further preferred embodiment of the invention, R 2  is the same or different at each instance and is H, an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms, which may be substituted by an alkyl group having 1 to 4 carbon atoms, but is preferably unsubstituted. 
     At the same time, in compounds of the invention that are processed by vacuum evaporation, the alkyl groups preferably have not more than five carbon atoms, more preferably not more than 4 carbon atoms, most preferably not more than 1 carbon atom. For compounds that are processed from solution, suitable compounds are also those substituted by alkyl groups, especially branched alkyl groups, having up to 10 carbon atoms or those substituted by oligoarylene groups, for example ortho-, meta- or para-terphenyl or branched terphenyl or quaterphenyl groups. 
     It may further be the case that the compound comprises exactly two or exactly three structures of formula (I), (IIa) to (IIk), (IIIa) to (IIIk), (IV-1) to (IV-20), (V-1) to (V-40), (VI-1) to (VI-40), (VII-1) to (VII-50) and/or (VIII-1) to (VIII-50), where preferably one of the aromatic or heteroaromatic ring systems to which at least one of the Y 1 , X 1 , X 2 , X 3  groups binds is shared by the two structures. 
     In a preferred configuration, the compounds are selected from compounds of the formula (D-1), (D-2), (D3) or (D-4): 
     
       
         
         
             
             
         
       
     
     where the L 1  group is a connecting group, preferably a bond or an aromatic or heteroaromatic ring system which has 5 to 40, preferably 5 to 30, aromatic ring atoms and may be substituted by one or more R radicals, and the further symbols and indices used have the definitions given above, especially for formula (I) and/or formula (V-1) to (V-40). 
     In a further preferred embodiment of the invention, L 1  is a bond or an aromatic or heteroaromatic ring system which has 5 to 14 aromatic or heteroaromatic ring atoms, preferably an aromatic ring system which has 6 to 12 carbon atoms, and which may be substituted by one or more R 1  radicals, but is preferably unsubstituted, where R 1  may have the definition given above, especially for formula (I). More preferably, L 1  is 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  may have the definition given above, especially for formula (I). 
     Further preferably, the symbol L 1  shown in formula (D4) inter alia is the same or different at each instance and is a bond or an aryl or heteroaryl radical having 5 to 24 ring atoms, preferably 6 to 13 ring atoms, more preferably 6 to 10 ring atoms, such that an aromatic or heteroaromatic group of an aromatic or heteroaromatic ring system is bonded to the respective atom of the further group directly, i.e. via an atom of the aromatic or heteroaromatic group. 
     It may additionally be the case that the L 1  group shown in formula (D4) comprises an aromatic ring system having not more than two fused aromatic and/or heteroaromatic 6-membered rings, preferably does not comprise any fused aromatic or heteroaromatic ring system. Accordingly, naphthyl structures are preferred over anthracene structures. In addition, fluorenyl, spirobifluorenyl, dibenzofuranyl and/or dibenzothienyl structures are preferred over naphthyl structures. 
     Particular preference is given to structures having no fusion, for example phenyl, biphenyl, terphenyl and/or quaterphenyl structures. 
     Examples of suitable aromatic or heteroaromatic ring systems L 1  are selected from the group consisting of ortho-, meta- or para-phenylene, ortho-, meta- or para-biphenylene, terphenylene, especially branched terphenylene, quaterphenylene, especially branched quaterphenylene, fluorenylene, spirobifluorenylene, dibenzofuranylene, dibenzothienylene and carbazolylene, each of which may be substituted by one or more R 1  radicals, but are preferably unsubstituted. 
     The abovementioned preferred embodiments may be combined with one another as desired within the restrictions defined in claim  1 . In a particularly preferred embodiment of the invention, the abovementioned preferences occur simultaneously. 
     Examples of preferred compounds according to the embodiments detailed above are the compounds shown in the following table: 
     
       
         
           
               
               
             
               
                   
               
             
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 1 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 2 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 3 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 4 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 5 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 6 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 7 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 8 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 9 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 10 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 11 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 12 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 13 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 14 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 15 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 16 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 17 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 18 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 19 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 20 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 21 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 22 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 23 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 24 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 25 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 26 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 27 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 28 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 29 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 30 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 31 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 32 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 33 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 34 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 35 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 36 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 37 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 38 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 39 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 40 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 41 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 42 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 43 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 44 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 45 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 46 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 47 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 48 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 49 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 50 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 51 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 52 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 53 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 54 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 55 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 56 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 57 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 58 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 59 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 60 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 61 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 62 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 63 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 64 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 65 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 66 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 67 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 68 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 69 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 70 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 71 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 72 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 73 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 74 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 75 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 76 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 77 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 78 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 79 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 80 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 81 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 82 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 83 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 84 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 85 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 86 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 87 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 88 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 89 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 90 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 91 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 92 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 93 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 94 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 95 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 96 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 97 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 98 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 99 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 100 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 101 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 102 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 103 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 104 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 105 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 106 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 107 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 108 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 109 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 110 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 111 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 112 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 113 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 114 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 115 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 116 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 117 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 118 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 119 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 120 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 121 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 122 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 123 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 124 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 125 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 126 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 127 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 128 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 129 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 130 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 131 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 132 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 133 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 134 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 135 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 136 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 137 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 138 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 139 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 140 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 141 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 142 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 143 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 144 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 145 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 146 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 147 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 148 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 149 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 150 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 151 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 152 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 153 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 154 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 155 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 156 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 157 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 157 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 158 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 159 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 160 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 161 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
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     Preferred embodiments of compounds of the invention are recited in detail in the examples, these compounds being usable alone or in combination with further compounds for all purposes of the invention. 
     Provided that the conditions specified in claim  1  are met, the abovementioned preferred embodiments can be combined with one another as desired. In a particularly preferred embodiment of the invention, the abovementioned preferred embodiments apply simultaneously. 
     The compounds of the invention are preparable in principle by various processes. However, the processes described hereinafter have been found to be particularly suitable. 
     Therefore, the present invention further provides a process for preparing the compounds of the invention, in which a base skeleton having a Z 1  group or a Z 2  group or a precursor of one of the Z 1 , Z 2  groups is synthesized, and at least one of the Y 1 , Y 2  groups is introduced by means of a nucleophilic aromatic substitution reaction or a coupling reaction. 
     Suitable compounds comprising a base skeleton having a Z 1  group or a Z 2  group are in many cases commercially available, and the starting compounds detailed in the examples are obtainable by known processes, and so reference is made thereto. 
     These compounds can be reacted with further compounds by known coupling reactions, the necessary conditions for this purpose being known to the person skilled in the art, and detailed specifications in the examples giving support to the person skilled in the art in conducting these reactions. 
     Particularly suitable and preferred coupling reactions which all lead to C—C bond formations and/or C—N bond formations are those according to BUCHWALD, SUZUKI, YAMAMOTO, STILLE, HECK, NEGISHI, SONOGASHIRA and HIYAMA. These reactions are widely known, and the examples will provide the person skilled in the art with further pointers. 
     The principles of the preparation processes detailed above are known in principle from the literature for similar compounds and can be adapted easily by the person skilled in the art for the preparation of the compounds of the invention. Further information can be found in the examples. 
     It is possible by these methods, if necessary followed by purification, for example recrystallization or sublimation, to obtain the compounds of the invention in high purity, preferably more than 99% (determined by means of  1 H NMR and/or HPLC). 
     The compounds of the invention may also be mixed with a polymer. It is likewise possible to incorporate these compounds covalently into a polymer. This is especially possible with compounds substituted by reactive leaving groups such as bromine, iodine, chlorine, boronic acid or boronic ester, or by reactive polymerizable groups such as olefins or oxetanes. These may find use as monomers for production of corresponding oligomers, dendrimers or polymers. The oligomerization or polymerization is preferably effected via the halogen functionality or the boronic acid functionality or via the polymerizable group. It is additionally possible to crosslink the polymers via groups of this kind. The compounds and polymers of the invention may be used in the form of a crosslinked or uncrosslinked layer. 
     The invention therefore further provides oligomers, polymers or dendrimers containing one or more of the above-detailed structures of the formula (I) and preferred embodiments of this formula or compounds of the invention, wherein one or more bonds of the compounds of the invention or of the structures of the formula (I) and preferred embodiments of that formula to the polymer, oligomer or dendrimer are present. According to the linkage of the structures of the formula (I) and preferred embodiments of this formula or of the compounds, these therefore form a side chain of the oligomer or polymer or are bonded within the main chain. The polymers, oligomers or dendrimers may be conjugated, partly conjugated or nonconjugated. The oligomers or polymers may be linear, branched or dendritic. For the repeat units of the compounds of the invention in oligomers, dendrimers and polymers, the same preferences apply as described above. 
     For preparation of the oligomers or polymers, the monomers of the invention are homopolymerized or copolymerized with further monomers. Preference is given to copolymers wherein the units of formula (I) or the preferred embodiments recited above and hereinafter are present to an extent of 0.01 to 99.9 mol %, preferably 5 to 90 mol %, more preferably 20 to 80 mol %. Suitable and preferred comonomers which form the polymer base skeleton are chosen from fluorenes (for example according to EP 842208 or WO 2000/022026), spirobifluorenes (for example according to EP 707020, EP 894107 or WO 2006/061181), paraphenylenes (for example according to WO 92/18552), carbazoles (for example according to WO 2004/070772 or WO 2004/113468), thiophenes (for example according to EP 1028136), dihydrophenanthrenes (for example according to WO 2005/014689), cis- and trans-indenofluorenes (for example according to WO 2004/041901 or WO 2004/113412), ketones (for example according to WO 2005/040302), phenanthrenes (for example according to WO 2005/104264 or WO 2007/017066) or else a plurality of these units. The polymers, oligomers and dendrimers may contain still further units, for example hole transport units, especially those based on triarylamines, and/or electron transport units. 
     Additionally of particular interest are compounds of the invention which feature a high glass transition temperature. In this connection, preference is given especially to compounds of the invention comprising structures of the formula (I) or the preferred embodiments recited above and hereinafter which have a glass transition temperature of at least 70° C., more preferably of at least 110° C., even more preferably of at least 125° C. and especially preferably of at least 150° C., determined in accordance with DIN 51005 (2005-08 version). 
     For the processing of the compounds of the invention from a liquid phase, for example by spin-coating or by printing methods, formulations of the compounds of the invention are required. These formulations may, for example, be solutions, dispersions or emulsions. For this purpose, it may be preferable to use mixtures of two or more solvents. Suitable and preferred solvents are, for example, toluene, anisole, o-, m- or p-xylene, methyl benzoate, mesitylene, tetralin, veratrole, THF, methyl-THF, THP, chlorobenzene, dioxane, phenoxytoluene, 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, α-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-dimethylphenyl)ethane, 2-methylbiphenyl, 3-methylbiphenyl, 1-methylnaphthalene, 1-ethylnaphthalene, ethyl octanoate, diethyl sebacate, octyl octanoate, heptylbenzene, menthyl isovalerate, cyclohexyl hexanoate or mixtures of these solvents. 
     The present invention therefore further provides a formulation or a composition comprising at least one compound of the invention and at least one further compound. The further compound may, for example, be a solvent, especially one of the abovementioned solvents or a mixture of these solvents. If the further compound comprises a solvent, this mixture is referred to herein as formulation. The further compound may alternatively be at least one further organic or inorganic compound which is likewise used in the electronic device, for example an emitter and/or a matrix material, where these compounds differ from the compounds of the invention. Suitable emitters and matrix materials are listed at the back in connection with the organic electroluminescent device. The further compound may also be polymeric. 
     The present invention therefore still further provides a composition comprising a compound of the invention and at least one further organofunctional material. Functional materials are generally the organic or inorganic materials introduced between the anode and cathode. Preferably, the organically functional material is selected from the group consisting of fluorescent emitters, phosphorescent emitters, emitters that exhibit TADF (thermally activated delayed fluorescence), host materials, electron transport materials, electron injection materials, hole conductor materials, hole injection materials, electron blocker materials, hole blocker materials, wide bandgap materials and n-dopants. 
     The present invention further provides for the use of a compound of the invention in an electronic device, especially in an organic electroluminescent device, preferably as emitter, more preferably as green, red or blue emitter. In this case, compounds of the invention preferably exhibit fluorescent properties and thus provide preferentially fluorescent emitters. In addition, compounds of the invention may as host materials, electron transport materials and/or hole conductor materials. It is especially possible here to use compounds of the invention in which many, preferably all, of the Z 1 , Z 2 , Z 3 , Z 4  groups are N advantageously as hole conductor material. It is also especially possible to use compounds of the invention in which many, preferably all, of the Z 1 , Z 2 , Z 3 , Z 4  groups are B advantageously as electron transport material. 
     The present invention still further provides an electronic device comprising at least one compound of the invention. An electronic device in the context of the present invention is a device comprising at least one layer comprising at least one organic compound. This component may also comprise inorganic materials or else layers formed entirely from inorganic materials. 
     The electronic device is preferably selected from the group consisting of More preferably, the electronic device is 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-laser), organic plasmon-emitting devices (D. M. 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.), more preferably organic light-emitting diodes (OLEDs), organic light-emitting diodes based on small molecules (sOLEDs), organic light-emitting diodes based on polymers (PLEDs), especially phosphorescent OLEDs. 
     The organic electroluminescent device comprises cathode, anode and at least one emitting layer. Apart from these layers, it may also comprise further layers, for example in each case one or more hole injection layers, hole transport layers, hole blocker layers, electron transport layers, electron injection layers, exciton blocker layers, electron blocker layers and/or charge generation layers. It is likewise possible for interlayers having an exciton-blocking function, for example, to be introduced between two emitting layers. However, it should be pointed out that not necessarily every one of these layers need be present. In this case, it is possible for the organic electroluminescent device to contain an emitting layer, or for it to contain a plurality of emitting layers. If a plurality of emission layers are present, these preferably have several emission maxima between 380 nm and 750 nm overall, such that the overall result is white emission; in other words, various emitting compounds which may fluoresce or phosphoresce are used in the emitting layers. Especially preferred are systems having three emitting layers, where the three layers show blue, green and orange or red emission. The organic electroluminescent device of the invention may also be a tandem electroluminescent device, especially for white-emitting OLEDs. 
     The compound of the invention may be used in different layers, according to the exact structure. Preference is given to an organic electroluminescent device comprising a compound of formula (I) or the above-detailed preferred embodiments in an emitting layer as emitter, preferably red, green or blue emitter. 
     When the compound of the invention is used as emitter in an emitting layer, preference is given to using a suitable matrix material which is known as such. 
     A preferred mixture of the compound of the invention and a matrix material contains between 99% and 1% by volume, preferably between 98% and 10% by volume, more preferably between 97% and 60% by volume and especially between 95% and 80% by volume of matrix material, based on the overall mixture of emitter and matrix material. Correspondingly, the mixture contains between 1% and 99% by volume, preferably between 2% and 90% by volume, more preferably between 3% and 40% by volume and especially between 5% and 20% by volume of the emitter, based on the overall mixture of emitter and matrix material. 
     Suitable matrix materials which can be used in combination with the inventive compounds are aromatic ketones, aromatic phosphine oxides or aromatic sulfoxides or sulfones, for example according to WO 2004/013080, WO 2004/093207, WO 2006/005627 or WO 2010/006680, triarylamines, carbazole derivatives, e.g. CBP (N,N-biscarbazolylbiphenyl) or the carbazole derivatives disclosed in WO 2005/039246, US 2005/0069729, JP 2004/288381, EP 1205527, WO 2008/086851 or WO 2013/041176, indolocarbazole derivatives, for example according to WO 2007/063754 or WO 2008/056746, indenocarbazole derivatives, for example according to WO 2010/136109, WO 2011/000455, WO 2013/041176 or WO 2013/056776, azacarbazole derivatives, for example according to EP 1617710, EP 1617711, EP 1731584, JP 2005/347160, bipolar matrix materials, for example according to WO 2007/137725, silanes, for example according to WO 2005/111172, azaboroles or boronic esters, for example according to WO 2006/117052, triazine derivatives, for example according to WO 2007/063754, WO 2008/056746, WO 2010/015306, WO 2011/057706, WO 2011/060859 or WO 2011/060877, zinc complexes, for example according to EP 652273 or WO 2009/062578, diazasilole or tetraazasilole derivatives, for example according to WO 2010/054729, diazaphosphole derivatives, for example according to WO 2010/054730, bridged carbazole derivatives, for example according to WO 2011/042107, WO 2011/060867, WO 2011/088877 and WO 2012/143080, triphenylene derivatives, for example according to WO 2012/048781, dibenzofuran derivatives, for example according to WO 2015/169412, WO 2016/015810, WO 2016/023608, WO 2017/148564 or WO 2017/148565, or biscarbazoles, for example according to JP 3139321 B2. 
     In addition, the co-host used may be a compound that does not take part in charge transport to a significant degree, if at all, as described, for example, in WO 2010/108579. Especially suitable in combination with the compound of the invention as co-matrix material are compounds which have a large bandgap and themselves take part at least not to a significant degree, if any at all, 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. 
     In a preferred configuration, a compound of the invention which is used as emitter is preferably used in combination with one or more phosphorescent materials (triplet emitters) and/or a compound which is a TADF (thermally activated delayed fluorescence) host material. Preference is given here to forming a hyperfluorescence and/or hyperphosphorescence system. 
     WO 2015/091716 Al and WO 2016/193243 A1 disclose OLEDs containing both a phosphorescent compound and a fluorescent emitter in the emission layer, where the energy is transferred from the phosphorescent compound to the fluorescent emitter (hyperphosphorescence). In this context, the phosphorescent compound accordingly behaves as a host material. As the person skilled in the art knows, host materials have higher singlet and triplet energies as compared to the emitters in order that the energy from the host material can also be transferred to the emitter with maximum efficiency. The systems disclosed in the prior art have exactly such an energy relation. 
     Phosphorescence in the context of this invention is understood to mean luminescence from an excited state having higher spin multiplicity, i.e. a spin state&gt;1, especially from an excited triplet state. In the context of this application, all luminescent complexes with transition metals or lanthanides, especially all iridium, platinum and copper complexes, shall be regarded as phosphorescent compounds. 
     Suitable phosphorescent compounds (=triplet emitters) are especially compounds which, when suitably excited, emit light, preferably in the visible region, and also contain at least one atom of atomic number greater than 20, preferably greater than 38 and less than 84, more preferably greater than 56 and less than 80, especially a metal having this atomic number. Preferred phosphorescence emitters used are compounds containing copper, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver, gold or europium, especially compounds containing 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 2010/102709, WO 2011/032626, WO 2011/066898, WO 2011/157339, WO 2012/007086, WO 2014/008982, WO 2014/023377, WO 2014/094961, WO 2014/094960, WO 2015/036074, WO 2015/104045, WO 2015/117718, WO 2016/015815, WO 2016/124304, WO 2017/032439, WO 2018/011186, WO 2018/001990, WO 2018/019687, WO 2018/019688, WO 2018/041769, WO 2018/054798, WO 2018/069196, WO 2018/069197, WO 2018/069273, WO 2018/178001, WO 2018/177981, WO 2019/020538, WO 2019/115423, WO 2019/158453 and WO 2019/179909. In general, all phosphorescent complexes as used for phosphorescent electroluminescent devices according to the prior art and as known to those skilled in the art in the field of organic electroluminescence are suitable, and the person skilled in the art will be able to use further phosphorescent complexes without exercising inventive skill. 
     A compound of the invention may preferably be used in combination with a TADF host material and/or a TADF emitter, as set out above. 
     The process referred to as thermally activated delayed fluorescence (TADF) is described, for example, by B. H. Uoyama et al., Nature 2012, Vol. 492, 234. In order to enable this process, a comparatively small singlet-triplet separation ΔE(S 1 −T 1 ) of less than about 2000 cm −1 , for example, is needed in the emitter. In order to open up the T 1 →S 1  transition which is spin-forbidden in principle, as well as the emitter, it is possible to provide a further compound in the matrix that has strong spin-orbit coupling, such that intersystem crossing is enabled via the spatial proximity and the interaction which is thus possible between the molecules, or the spin-orbit coupling is generated by means of a metal atom present in the emitter. 
     In a further embodiment of the invention, the organic electroluminescent device of the invention does not contain any separate hole injection layer and/or hole transport layer and/or hole blocker layer and/or electron transport layer, meaning that the emitting layer directly adjoins the hole injection layer or the anode, and/or the emitting layer directly adjoins the electron transport layer or the electron injection layer or the cathode, as described, for example, in WO 2005/053051. It is additionally possible to use a metal complex identical or similar to the metal complex in the emitting layer as hole transport or hole injection material directly adjoining the emitting layer, as described, for example, in WO 2009/030981. 
     Also preferred is an organic electroluminescent device is an organic electroluminescent device comprising a compound of formula (I) or the above-detailed preferred embodiments in a hole-conducting layer as hole conductor material. Preference is given here especially to compounds in which at least one, preferably two, of the Z 1  and Z 2  groups is/are N and at least one, preferably two, of the Y 1  and Y 2  groups is/are N(Ar), N(R), P(Ar), P(R), O, S or Se, preferably N(Ar), N(R), O or S, more preferably N(Ar). In addition, preference is given here especially to compounds in which at least one, preferably two, of the Z 1 , Z 2  groups is/are N and at least one, preferably two, of the Z 3 , Z 4  groups is/are N. 
     Also preferred is an organic electroluminescent device comprising a compound of formula (I) or the above-detailed preferred embodiments in an electron-conducting layer as electron transport material. Preference is given here especially to compounds in which at least one, preferably two, of the Z 1  and Z 2  groups is/are B and at least one, preferably two, of the Z 3  and Z 4  groups is/are B. In addition, preference is given here especially to compounds in which at least one, preferably two, of the Z 1 , Z 2  groups is/are B and at least one, preferably two, of the Z 3 , Z 4  groups is/are B. 
     In the further layers of the organic electroluminescent device of the invention, it is possible to use any materials as typically used according to the prior art. The person skilled in the art will therefore be able, without exercising inventive skill, to use any materials known for organic electroluminescent devices in combination with the inventive compounds of formula (I) or the above-recited preferred embodiments. 
     Additionally preferred is an organic electroluminescent device, characterized in that one or more layers are coated by a sublimation process. In this case, the materials are applied by vapor deposition in vacuum sublimation systems at an initial pressure of less than 10 −5  mbar, preferably less than 10 −6  mbar. However, it is also possible that the initial pressure is even lower, for example less than 10 −7  mbar. 
     Preference is likewise given to an organic electroluminescent device, characterized in that one or more layers are coated by the OVPD (organic vapor phase deposition) method or with the aid of a carrier gas sublimation. In this case, the materials are applied at a pressure between 10 −5  mbar and 1 bar. A special case of this method is the OVJP (organic vapor jet printing) method, in which the materials are applied directly by a nozzle and thus structured. 
     Preference is additionally given to an organic electroluminescent device, characterized in that one or more layers are produced from solution, for example by spin-coating, or by any printing method, for example screen printing, flexographic printing, offset printing, LITI (light-induced thermal imaging, thermal transfer printing), inkjet printing or nozzle printing. For this purpose, soluble compounds are needed, which are obtained, for example, through suitable substitution. 
     Formulations for applying a compound of formula (I) or the preferred embodiments thereof detailed above are novel. The present invention therefore further provides formulations containing at least one solvent and a compound according to formula (I) or the preferred embodiments thereof detailed above. 
     In addition, hybrid methods are possible, in which, for example, one or more layers are applied from solution and one or more further layers are applied by vapor deposition. 
     Those skilled in the art are generally aware of these methods and are able to apply them without exercising inventive skill to organic electroluminescent devices comprising the compounds of the invention. 
     The compounds of the invention and the organic electroluminescent devices of the invention have the particular feature of an improved lifetime over the prior art. At the same time, the further electronic properties of the electroluminescent devices, such as efficiency or operating voltage, remain at least equally good. In a further variant, the compounds of the invention and the organic electroluminescent devices of the invention especially feature improved efficiency and/or operating voltage and higher lifetime compared to the prior art. 
     The electronic devices of the invention, especially organic electroluminescent devices, are notable for one or more of the following surprising advantages over the prior art:
     1. Electronic devices, especially organic electroluminescent devices comprising compounds of formula (I) or the preferred embodiments as emitters that have been recited above and hereinafter have very narrow emission bands having very low FWHM (Full Width Half Maximum) values, and lead to particularly pure-color emission, recognizable by the low CIE y values. What is particularly surprising here is that both blue emitters having low FWHM values and emitters having low FWHM that emit in the green, yellow or red region of the color spectrum are provided.   2. Electronic devices, especially organic electroluminescent devices, comprising compounds of formula (I) or the preferred embodiments recited above and hereinafter, especially as emitter, as hole conductor material and/or as electron transport material, have a very good lifetime. In this context, these compounds especially bring about low roll-off, i.e. a small drop in power efficiency of the device at high luminances.   3. Electronic devices, especially organic electroluminescent devices, comprising compounds of formula (I) or the preferred embodiments that have been recited above and hereinafter, have excellent efficiency as emitter, as hole conductor material and/or as electron transport material. In this context, compounds of the invention having structures of formula (I) or the preferred embodiments recited above and hereinafter bring about a low operating voltage when used in electronic devices.   4. The inventive compounds of formula (I) or the preferred embodiments recited above and hereinafter exhibit very high stability and lifetime.   5. With compounds of formula (I) or the preferred embodiments recited above and hereinafter, it is possible to avoid the formation of optical loss channels in electronic devices, especially organic electroluminescent devices. As a result, these devices feature a high PL efficiency and hence high EL efficiency of emitters, and excellent energy transmission of the matrices to dopants.   6. Compounds of formula (I) or the preferred embodiments recited above and hereinafter have excellent glass film formation.   7. Compounds of formula (I) or the preferred embodiments recited above and hereinafter form very good films from solutions and show excellent solubility.   

     These abovementioned advantages are not accompanied by an inordinately high deterioration in the further electronic properties. 
     It should be pointed out that variations of the embodiments described in the present invention are covered by the scope of this invention. Any feature disclosed in the present invention may, unless this is explicitly ruled out, be exchanged for alternative features which serve the same purpose or an equivalent or similar purpose. Thus, any feature disclosed in the present invention, unless stated otherwise, should 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 with one another in any manner, unless particular features and/or steps are mutually exclusive. This is especially true of preferred features of the present invention. Equally, features of non-essential combinations may be used separately (and not in combination). 
     It should also be pointed out that many of the features, and especially those of the preferred embodiments of the present invention, should themselves be regarded as inventive and not merely as some of the embodiments of the present invention. For these features, independent protection may be sought in addition to or as an alternative to any currently claimed invention. 
     The technical teaching disclosed with the present invention may be abstracted and combined with other examples. 
     The invention is illustrated in more detail by the examples which follow, without any intention of restricting it thereby. The person skilled in the art will be able to use the information given to execute the invention over the entire scope disclosed and to prepare further compounds of the invention without exercising inventive skill and to use them in electronic devices or to employ the process of the invention. 
    
    
     EXAMPLES 
     The syntheses which follow, unless stated otherwise, are conducted under a protective gas atmosphere in dried solvents. The metal complexes are additionally handled with exclusion of light or under yellow light. The solvents and reagents can be purchased, for example, from Sigma-ALDRICH or ABCR. The respective figures in square brackets or the numbers quoted for individual compounds relate to the CAS numbers of the compounds known from the literature. In the case of compounds that can have multiple enantiomeric, diastereomeric or tautomeric forms, one form is shown in a representative manner. 
     Synthesis of Synthons S 
     Example S1 
     
       
         
         
             
             
         
       
     
     Procedure analogous to Chung-Chieh Lee et al., Synthesis 2008, 9, 1359. Complete procedure including workup under protective gas. 
     A mixture of 34.0 g (120 mmol) of 1-bromo-2-iodobenzene [583-55-1], 8.5 g (50 mmol) of 2,3-dihydro-1H-perimidine [69098-80-2], 20.7 g (150 mmol) of potassium carbonate, 1.9 g (10 mmol) of copper iodide [7681-65-4], 2.9 g (20 mmol) of 1R,2R—N,N-dimethylcyclohexane-1,2-diamine [67579-81-8], 50 g of glass beads and 200 ml of o-xylene is stirred at 130° C. for 24 h. After cooling, 300 ml of ethyl acetate and 500 ml of water are added to the reaction mixture, and the organic phase is removed, washed once with 500 ml of water and twice with 300 ml each time of saturated sodium chloride solution, and dried over magnesium sulfate. The mixture is filtered through a silica gel bed in the form of an ethyl acetate slurry, the filtrate is concentrated to dryness, the residue is boiled with 150 ml of ethanol, the solids are filtered off with suction, and these are washed twice with 30 ml of ethanol, dried under reduced pressure and recrystallized from acetonitrile/DCM (dichloromethane). Further purification can be effected by flash chromatography on an automated column system (Torrent, from A. Semrau). Yield: 15.8 g (33 mmol) 65%; purity about 95% by  1 H NMR. 
     The following compounds can be prepared analogously: 
     
       
         
           
               
               
               
               
             
               
                   
               
               
                 Ex.. 
                 Reactants 
                 Product 
                 Yield 
               
               
                   
               
             
            
               
                 S2 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 81% 
               
               
                   
               
               
                   
                 69098-82-4 
                   
                   
               
               
                   
               
               
                 S3 
                                   
   96843-22-0 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 61% 
               
               
                   
               
               
                 S4 
                                   
   
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 65% 
               
               
                   
                 900806-53-3 
                   
                   
               
               
                   
               
               
                 S5 
                                   
   1846603-15-3 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 59% 
               
               
                   
               
               
                 S6 
                                   
   676267-05-3 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 52% 
               
               
                   
               
               
                 S7 
                                   
   90948-03-1 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 55% 
               
               
                   
               
               
                 S8 
                                   
   93188-73-9 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 63% 
               
               
                   
               
               
                 S9 
                                   
   916747-51-8 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 67% 
               
               
                   
               
               
                 S10 
                                   
   1541101-10-3 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 50% 
               
               
                   
               
               
                 S11 
                                   
   184885-74-3 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 54% 
               
               
                   
               
               
                 S12 
                                   
   1776056-64-4 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 50% 
               
               
                   
               
               
                 S13 
                                   
   1801624-64-5 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 52% 
               
               
                   
               
               
                 S14 
                                   
   1801624-66-7 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 56% 
               
               
                   
               
               
                 S15 
                                   
   52776-05-3 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 49% 
               
               
                   
               
               
                 S16 
                                   
   103698-58-4 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 53% 
               
               
                   
               
               
                 S17 
                                   
   192865-46-6 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 46% 
               
               
                   
               
               
                 S18 
                                   
   1548470-73-0 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 50% 
               
               
                   
               
               
                 S19 
                                   
   2226847-79-4 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 56% 
               
               
                   
               
               
                 S20 
                                   
   1548471-03-9 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 55% 
               
               
                   
               
               
                 S21 
                                   
   140898-76-6 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 52% 
               
               
                   
               
               
                 S22 
                                   
   2086712-49-2 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 55% 
               
               
                   
               
               
                 S23 
                                   
   2222443-14-1 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 58% 
               
               
                   
               
               
                 S24 
                                   
   2222442-94-4 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 48% 
               
               
                   
               
               
                 S25 
                                   
   1549979-42-1 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 50% 
               
               
                   
               
               
                 S26 
                                   
   2173184-34-2 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 56% 
               
               
                   
               
               
                 S27 
                                   
   1549979-37-4 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 54% 
               
               
                   
               
               
                 S28 
                                   
   2186703-50-2 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 43% 
               
               
                   
               
            
           
         
       
     
     Example, Dopant D1 
     Steps 1 to 3 of the sequence that follows are conducted as a three-stage one-pot reaction. The workup in step 3 is effected under protective gas. 
     Step 1: Lithiation of S1: 
     
       
         
         
             
             
         
       
     
     A baked-out, argon-inertized four-neck flask with magnetic stirrer bar, dropping funnel, water separator, reflux condenser and argon blanketing is charged with 24.0 g (50 mmol) of 51 in 1700 ml of tert-butylbenzene. The reaction mixture is cooled down to −40° C., and then 110.5 ml (210 mmol) of tert-butyllithium, 1.9 M in n-pentane, is added dropwise. The mixture is stirred at −40° C. for a further 30 min, allowed to warm up to room temperature, then heated 70° C., in the course of which the n-pentane is distilled off via the water separator over about 1 h. 
     Step 2: Transmetalation and Cyclization 
     
       
         
         
             
             
         
       
     
     The reaction mixture is cooled back down to −40° C. 10.4 ml (110 mmol) of boron tribromide is added dropwise over a period of about 10 min. On completion of addition, the reaction mixture is stirred at RT for 1 h. Then the reaction mixture is cooled down to 0° C., and 19.2 ml (110 mmol) of di-iso-propylethylamine is added dropwise over a period of about 30 min. Then the reaction mixture is stirred at 160° C. for 16 h. After cooling, di-iso-propylethylammmonium hydrobromide is filtered off using a double-ended frit, and the filtrate is cooled down to −78° C. 
     Step 3: Arylation 
     
       
         
         
             
             
         
       
     
     A second baked-out, argon-inertized Schlenk flask with magnetic stirrer bar is charged with 27.8 g (150 mmol) of 2-bromo-1,3-dimethylbenzene [576-22-7] in 1000 ml of diethyl ether and cooled down to −78° C. Then 60.0 ml (150 mmol) of n-butyllithium, 2.5 M in n-hexane, is added dropwise thereto and the mixture is stirred for a further 30 min. The reaction mixture is allowed to warm up to RT and stirred for a further 1 h, and the solvent is removed completely under reduced pressure. The lithium organyl is suspended in 300 ml of toluene and transferred into the cryogenic reaction mixture from step 2. The mixture is stirred for a further 1 h, and the reaction mixture is left to warm up to RT overnight. 15 ml of acetone is added cautiously to the reaction mixture, which is concentrated to dryness. The oily residue is absorbed with DCM onto ISOLUTE® and hot-filtered through a silica gel bed with a pentane-DCM mixture (10:1). The filtrate is concentrated to dryness. The residue is subjected to flash chromatography twice, silica gel, n-heptane/ethyl acetate, Torrent automated column system from A. Semrau. 
     Step 4: Oxidation to D1 
     
       
         
         
             
             
         
       
     
     Procedure analogous to R. Doringer et al., Monatshefte für Chemie, 2006, 137, 185. The product from step 3 is taken up in 150 ml of chlorobenzene, 20 g of activated 3 A molecular sieve is added, and the mixture is stirred in the dark under air at 60° C. until oxidation is complete (about 5 h). The molecular sieve is filtered off and rinsed with a little chlorobenzene, and the mixture is concentrated to dryness under reduced pressure. The residue is subjected to flash chromatography twice, silica gel, n-heptane/ethyl acetate, Torrent automated column system from A. Semrau. Further purification is effected by repeated hot extraction crystallization with DCM/acetonitrile and final fractional sublimation or heat treatment under reduced pressure. Yield: 12.43 g (22 mmol) 44%; purity about 99.9% by  1 H NMR. 
     The following compounds can be prepared analogously: 
     
       
         
           
               
               
               
               
             
               
                   
               
               
                 Ex. 
                 Reactant 
                 Products 
                 Yield 
               
               
                   
               
             
            
               
                 D2 
                 S2                    
   3972-65-4 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 56% 
               
               
                   
               
               
                 D3 
                 S3                    
   
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 40% 
               
               
                   
                 126866-29-3 
                   
                   
               
               
                   
               
               
                 D4 
                 S4                    
   576-83-0 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 45% 
               
               
                   
               
               
                 D5 
                 S5                    
   10368-73-7 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 23% 
               
               
                   
               
               
                 D6 
                 S6                    
   90-11-9 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 38% 
               
               
                   
               
               
                 D7 
                 S7                    
   7412-67-1 Use in step 3 as ethereal standard solution 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 17% 
               
               
                   
               
               
                 D8 
                 S8                    
   23674-20-6 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 29% 
               
               
                   
               
               
                 D9 
                 S9                    
   576-83-0 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 46% 
               
               
                   
               
               
                 D10 
                 S10                    
   576-83-0 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 50% 
               
               
                   
               
               
                 D11 
                 S11                    
   23674-20-6 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 22% 
               
               
                   
               
               
                 D12 
                 S12                    
   23674-20-6 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 48% 
               
               
                   
               
               
                 D13 
                 S13                    
   576-83-0 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 42% 
               
               
                   
               
               
                 D14 
                 S14                    
   57190-17-7 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 26% 
               
               
                   
               
               
                 D15 
                 S15                    
   10368-73-7 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 24% 
               
               
                   
               
               
                 D16 
                 S16                    
   10368-73-7 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 22% 
               
               
                   
               
               
                 D17 
                 S17                    
   576-83-0 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 40% 
               
               
                   
               
               
                 D18 
                 S18                    
   576-83-0 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 23% 
               
               
                   
               
               
                 D19 
                 S19                    
   50548-45-3 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 21% 
               
               
                   
               
               
                 D20 
                 S19                    
 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 19% 
               
               
                   
               
               
                   
                 50548-45-3 
                   
                   
               
               
                   
               
               
                 D21 
                 S21                    
   942615-32-9 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 26% 
               
               
                   
               
               
                 D22 
                 S22                    
   576-83-0 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 41% 
               
               
                   
               
               
                 D23 
                 S23                    
   64248-56-2 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 16% 
               
               
                   
               
               
                 S24 
                 S24                    
   1562418-80-7 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 13% 
               
               
                   
               
               
                 D25 
                 S25                    
   2052-07-5 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 37% 
               
               
                   
               
               
                 D26 
                 S25                    
   1801624-97-4 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 42% 
               
               
                   
               
               
                 D27 
                 S27                    
   758673-19-5 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 36% 
               
               
                   
               
               
                 D28 
                 S27                    
   3972-65-4 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 17% 
               
               
                   
               
               
                 D100 
                 Steps 1, 2 &amp; 4                    
   75-44-5 1 M in toluene 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 30% 
               
               
                   
               
               
                 D200 
                 Steps 1, 2 &amp; 4                    
   
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 21% 
               
               
                   
                 824-72-6 
                 Racemate 
                   
               
               
                   
               
               
                 D300 
                 Steps 1, 2 &amp; 4                    
   10545-99-0 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 28% 
               
               
                   
               
               
                 D400 
                 Steps 1, 2 &amp; 4                    
   7791-25-5 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 31% 
               
               
                   
               
               
                 D500 
                 Steps 1, 2 &amp; 4                    
 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 17% 
               
               
                   
               
               
                   
                 103-33-3 
                   
                   
               
               
                   
               
               
                 D600 
                 Steps 1, 2 &amp; 4                    
   18395-90-9 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 34% 
               
               
                   
               
               
                 D601 
                 Steps 1, 2 &amp; 4                    
   80-10-4 
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 38% 
               
               
                   
               
            
           
         
       
     
     Example, Dopants D6PA, D6PB and D6PC 
     
       
         
         
             
             
         
       
     
     Preparation from D6 by flash vacuum pyrolysis, carrier gas: argon, reduced pressure about 10 −2  torr, pyrolysis zone temperature 550° C., catalyst: 1% PdO on alumina. Chromatography separation, DCM/n-heptane, silica gel. Yields: D100A 9%; D100B 15%, D100C 8%. 
     Production of OLED Components 
     1) Vacuum-Processed Components: 
     OLEDs of the invention and OLEDs according to the prior art are produced by a general method according to WO 2004/058911, which is adapted to the circumstances described here (variation in layer thickness, materials used). 
     In the examples which follow, the results for various OLEDs are presented. Cleaned glass plates (cleaning in Miele laboratory glass washer, Merck Extran detergent) coated with structured ITO (indium tin oxide) of thickness 50 nm are pretreated with UV ozone for 25 minutes (PR-100 UV ozone generator from UVP) and, within 30 min, for improved processing, coated with 20 nm of PEDOT:PSS (poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate), purchased as CLEVIOS™ P VP AI 4083 from Heraeus Precious Metals GmbH Deutschland, spun on from aqueous solution) and then baked at 180° C. for 10 min. These coated glass plates form the substrates to which the OLEDs are applied. 
     The OLEDs basically have the following layer structure: Substrate/hole injection layer 1 (HIL1) consisting of Ref-HTM1 doped with 5% NDP-9 (commercially available from Novaled), 20 nm/hole transport layer 1 (HTL1) composed of: 150 nm HTM1 for UV &amp; blue OLEDs; 50 nm for green and yellow OLEDs; 110 nm for red OLEDs/hole transport layer 2 (HTL2) composed of: 10 nm for blue OLEDs; 20 nm for green &amp; yellow OLEDs; 10 nm for red OLEDs/emission layer (EML): 25 nm for blue OLEDs; 40 nm for green &amp; yellow OLEDs; 35 nm for red OLEDs/hole blocker layer (HBL) 10 nm/electron transport layer (ETL) 30 nm/electron injection layer (EIL) composed of 1 nm ETM2/and finally a cathode. The cathode is formed by an aluminum layer of thickness 100 nm. 
     First of all, vacuum-processed OLEDs are described. For this purpose, all the materials are applied by thermal vapor deposition in a vacuum chamber. In this case, the emission layer always consists of at least one matrix material (host material) and an emitting dopant (emitter) which is added to the matrix material(s) in a particular proportion by volume by co-evaporation. Details given in such a form as SMB1:D1 (95:5%) mean here that the material SEB1 is present in the layer in a proportion by volume of 95% and D1 in a proportion of 5%. Analogously, the electron transport layer may also consist of a mixture of two materials. The exact structure of the OLEDs can be found in table 1. The materials used for production of the OLEDs are shown in table 3. 
     The OLEDs are characterized in a standard manner. For this purpose, the electroluminescence spectra, the current efficiency (measured in cd/A), the power efficiency (measured in Im/W) and the external quantum efficiency (EQE, measured in percent) are, as a function of luminance, calculated from current-voltage-luminance characteristics (IUL characteristics) assuming Lambertian radiation characteristics. The electroluminescent spectra are recorded at a luminance of 1000 cd/m 2 , and these are used to infer the emission color and the EL-FWHM values (ELectroluminescence-Full Width Half Maximum—width of the EL emission spectra at half the peak height in eV; for better comparability over the entire spectral range). 
     Use of compounds of the invention as materials in OLEDs: One use of the compounds of the invention can be as dopant in the emission layer and as transport or blocker materials (HBL) in OLEDs. The compounds D-Ref.1 according to table 3 are used as a comparison according to the prior art. The results for the OLEDs are collated in table 2. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Structure of the OLEDs 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Ex. 
                 EML 
                 HBL 
                 ETL 
               
               
                   
                   
               
            
           
           
               
            
               
                 Blue OLEDs (400-499 nm) 
               
            
           
           
               
               
               
               
               
            
               
                   
                 D-Ref.1 
                 SMB1:D-Ref.1 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D1 
                 SMB1:D1 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D2 
                 SMB4:D2 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D3 
                 SMB1:D3 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D4 
                 SMB1:D4 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D7 
                 SMB1:D7 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D9 
                 SMB1:D9 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (92%:8%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D10 
                 SMB1:D10 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D12 
                 SMB1:D12 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D13 
                 SMB1:D13 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D14 
                 SMB1:D14 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D17 
                 SMB1:D17 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D18 
                 SMB1:D18 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D19 
                 SMB1:D19 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D22 
                 SMB1:D22 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D23 
                 SMB1:D23 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D24 
                 SMB1:D24 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D25 
                 SMB3:D25 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D26 
                 SMB2:D26 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D100 
                 SMB4:D100 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D200 
                 SMB1:D1 
                 D200 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
            
           
           
               
            
               
                 Green &amp; yellow OLEDs (500-590 nm) 
               
            
           
           
               
               
               
               
               
            
               
                   
                 D-D300 
                 SMB1:D300 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (95%:5%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D6PA 
                 SMB1:D6PA 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (97%:3%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D6PB 
                 SMB1:D6PB 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (97%:3%) 
                   
                 (50%:50%) 
               
               
                   
                 D-D6PC 
                 SMB1:D6PC 
                 ETM1 
                 ETM1:ETM2 
               
               
                   
                   
                 (97%:3%) 
                   
                 (50%:50%) 
               
               
                   
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Results for the vacuum-processed OLEDs 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                   
                 EQE (%) 
                 Voltage (V) 
                   
                 EL-FWHM 
               
               
                   
                 Ex. 
                 1000 cd/m 2   
                 1000 cd/m 2   
                 Color 
                 [eV] 
               
               
                   
                   
               
            
           
           
               
               
            
               
                   
                 Blue OLEDs (430-475 nm) 
               
               
                   
                 Sky blue OLEDs (476-504) 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Ref.1 
                 6.1 
                 4.6 
                 blue 
                 0.17 
               
               
                   
                 D-D1 
                 6.3 
                 4.5 
                 blue 
                 0.14 
               
               
                   
                 D-D2 
                 6.5 
                 4.4 
                 blue 
                 0.16 
               
               
                   
                 D-D3 
                 6.2 
                 4.3 
                 blue 
                 0.16 
               
               
                   
                 D-D4 
                 6.5 
                 4.4 
                 blue 
                 0.16 
               
               
                   
                 D-D7 
                 6.6 
                 4.4 
                 blue 
                 0.17 
               
               
                   
                 D-D9 
                 6.4 
                 4.5 
                 blue 
                 0.15 
               
               
                   
                 D-D10 
                 6.5 
                 4.6 
                 blue 
                 0.14 
               
               
                   
                 D-D12 
                 7.0 
                 4.4 
                 blue 
                 0.16 
               
               
                   
                 D-D13 
                 6.9 
                 4.5 
                 blue 
                 0.15 
               
               
                   
                 D-D14 
                 6.4 
                 4.4 
                 blue 
                 0.15 
               
               
                   
                 D-D17 
                 7.3 
                 4.3 
                 blue 
                 0.16 
               
               
                   
                 D-D18 
                 6.5 
                 4.4 
                 blue 
                 0.17 
               
               
                   
                 D-D19 
                 7.2 
                 4.3 
                 sky blue 
                 0.17 
               
               
                   
                 D-D22 
                 5.9 
                 4.4 
                 blue 
                 0.14 
               
               
                   
                 D-D23 
                 6.6 
                 4.3 
                 sky blue 
                 0.16 
               
               
                   
                 D-D24 
                 6.6 
                 4.4 
                 sky blue 
                 0.17 
               
               
                   
                 D-D25 
                 6.4 
                 4.4 
                 blue 
                 0.14 
               
               
                   
                 D-D26 
                 6.8 
                 4.3 
                 sky blue 
                 0.15 
               
               
                   
                 D-D100 
                 6.1 
                 4.3 
                 blue 
                 0.21 
               
               
                   
                 D-D200 
                 6.4 
                 4.5 
                 blue 
                 0.15 
               
            
           
           
               
               
            
               
                   
                 Green OLEDs (505-549 nm) 
               
               
                   
                 Yellow OLEDs (550-600 nm) 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 D-D300 
                 6.9 
                 4.2 
                 green 
                 0.22 
               
               
                   
                 D-D6PA 
                 6.6 
                 4.3 
                 yellow 
                 0.21 
               
               
                   
                 D-D6PB 
                 7.1 
                 4.2 
                 yellow 
                 0.17 
               
               
                   
                 D-D6PC 
                 6.8 
                 4.4 
                 yellow 
                 0.14 
               
               
                   
                   
               
            
           
         
       
     
     2) Solution-Processed Components: 
     The production of solution-based OLEDs is fundamentally described in the literature, for example in WO 2004/037887 and WO 2010/097155. The examples that follow combined the two production processes (application from the gas phase and solution processing), such that layers up to and including emission layer were processed from solution and the subsequent layers (hole blocker layer/electron transport layer) were applied by vapor deposition under reduced pressure. For this purpose, the previously described general methods are matched to the circumstances described here (layer thickness variation, materials) and combined as follows. 
     The construction used is thus as follows:
         substrate,   ITO (50 nm),   PEDOT (20 nm),   hole transport layer (HIL2) (20 nm),   emission layer (92% host, 8% dopant) (60 nm),   electron transport layer (ETM1 50%+ETM2 50%) (20 nm),   cathode (Al).       

     Substrates used are glass plaques coated with structured ITO (indium tin oxide) of thickness 50 nm. For better processing, these are coated with the buffer (PEDOT) Clevios P VP AI 4083 (Heraeus Clevios GmbH, Leverkusen); PEDOT is at the top. Spin-coating is effected under air from water. The layer is subsequently baked at 180° C. for 10 minutes. The hole transport layer and the emission layer are applied to the glass plates thus coated. The hole transport layer is the polymer of the structure shown in table 3, which was synthesized according to WO 2010/097155. The polymer is dissolved in toluene, such that the solution typically has a solids content of about 5 g/l when, as is the case here, the layer thickness of 20 nm typical of a device is to be achieved by means of spin-coating. The layers are spun on in an inert gas atmosphere, argon in the present case, and baked at 180° C. for 60 min. 
     The emission layer is always composed of at least one matrix material (host material) and an emitting dopant (emitter). Details given in such a form as H1 (92%):D (8%) mean here that the material H1 is present in the emission layer in a proportion by weight of 92% and the dopant D in a proportion by weight of 8%. The mixture for the emission layer is dissolved in toluene or chlorobenzene. The typical solids content of such solutions is about 18 g/l when, as here, the layer thickness of 60 nm which is typical of a device is to be achieved by means of spin-coating. The layers are spun on in an inert gas atmosphere, argon in the present case, and baked at 140 to 160° C. for 10 minutes. The materials used are shown in table 3. 
     The materials for the electron transport layer and for the cathode are applied by thermal vapor deposition in a vacuum chamber. The electron transport layer, for example, may consist of more than one material, the materials being added to one another by co-evaporation in a particular proportion by volume. Details given in such a form as ETM1:ETM2 (50%:50%) mean here that the ETM1 and ETM2 materials are present in the layer in a proportion by volume of 50% each. The materials used in the present case are shown in table 3. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Results for the solution-processed OLEDs 
               
               
                 at 1000 cd/m 2   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                   
                 EQE 
                 Voltage 
                   
                 EL-FWHM 
               
               
                 Ex. 
                 Dopant 
                 (%) 
                 (V) 
                 Color 
                 [eV] 
               
               
                   
               
            
           
           
               
            
               
                 Blue OLEDs (430-475 nm) 
               
            
           
           
               
               
               
               
               
               
            
               
                 Ref.-Sol. 
                 Ref.-D1 
                 4.4 
                 4.9 
                 blue 
                 0.19 
               
               
                 Sol.-D5 
                 D5 
                 5.3 
                 4.7 
                 blue 
                 0.19 
               
               
                 Sol.-D6 
                 D6 
                 5.0 
                 4.5 
                 blue 
                 0.24 
               
               
                 Sol.-D11 
                 D11 
                 5.1 
                 4.7 
                 blue 
                 0.18 
               
               
                 Sol.-D15 
                 D15 
                 5.2 
                 4.6 
                 blue 
                 0.17 
               
               
                 Sol.-D16 
                 D16 
                 5.2 
                 4.7 
                 blue 
                 0.17 
               
               
                 Sol.-D20 
                 D20 
                 3.7 
                 4.7 
                 blue 
                 0.19 
               
               
                 Sol.-D21 
                 D21 
                 4.8 
                 4.6 
                 blue 
                 0.21 
               
               
                 Sol.-D27 
                 D27 
                 4.9 
                 4.6 
                 blue 
                 0.15 
               
               
                 Sol.-D28 
                 D28 
                 5.1 
                 4.7 
                 blue 
                 0.19 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 3 
               
               
                   
               
               
                 Structural formulae of the materials used 
               
               
                   
               
             
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 HTM1 
               
               
                 [136463-07-5] 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 HTM2 
               
               
                 [1450933-44-4] 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 SMB1 
               
               
                 [1087346-88-0] 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 SMB2 
               
               
                 [667940-34-3] 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 SMB3 
               
               
                 [1627916-48-6] 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 H1 
               
               
                 [1818872-85-3] 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 SMB4 
               
               
                 [342638-54-4] 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 [1805802-42-9] 
               
               
                 Ref.-D1 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 ETM1 
               
               
                 [1233200-52-6] 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 ETM2 
               
               
                 [25387-93-3] 
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 HIL2 
               
               
                   
               
            
           
         
       
     
     By comparison with the references, some of the compounds of the invention show narrower or comparably narrow electroluminescence spectra, recognizable by the smaller or equal EL-FWHM values (ELectroluminescence-Full Width Half Maximum—width of the EL emission spectra in eV at half the peak height). Narrower electroluminescence spectra lead to a distinct improvement in color purity (lower CIE y values). Moreover, EQE values (External Quantum Efficiencies) are distinctly greater and operating voltages are lower compared to the reference, which leads to a distinct improvement in power efficiencies of the device and hence to lower power consumption.