metal complex

Abstract

The present invention relates to dinuclear metal complexes and electronic devices, in particular organic electroluminescent devices, comprising said metal complexes.

Description

[0001] The present invention relates to dinuclear metal complexes suitable for use as emitters in organic electroluminescent devices.

[0002] According to the prior art, triplet emitters used in phosphorescent organic electroluminescent devices (OLEDs) are in particular ortho-metalated iridium complexes with aromatic ligands, wherein the ligands are bound to the metal via a negatively charged carbon atom and an uncharged nitrogen atom. WO 2018 / 041769 discloses dinuclear iridium complexes, in particular for red luminescence, which can be processed from solution.

[0003] Generally, the external quantum efficiency of an OLED assembly can be significantly increased when the transition dipole moment of the luminescence of the present emitters is arranged as level as possible, i.e. in the plane of the luminescent layer. This effect is known for vacuum-processed singlet and triplet emitters as well as for solution-processed singlet emitters. The alignment of solution-processed polymers is also known. In contrast, the orientation of triplet emitters in solution is a still unsolved technical problem. For example, it is well known that emitters which can be oriented in the case of vapor deposition cannot be oriented from solution (e.g. Lampe et al., Chem. Mater., 2016, Vol. 28, pp. 712-715). The review article of 2019 (Watanabe et al., Bull. Chem. Soc. Jpn., 2019, Vol. 92, pp. 716-728) also describes the orientation from solution as an outstanding problem. The fact that compounds which can be vapor-deposited in an oriented manner form non-oriented films from solution is here attributed to differences in the film formation mechanism with regard to the kinetic stability and molecular dynamics in solution.

[0004] In the case of vacuum-processed triplet emitters, orientation and thus the improvement of the external quantum efficiency of the OLED can be achieved by substituting the optically active ligand with groups which cause orientation via interaction with the surface during vapor deposition. Suitable substituents here are for example biphenyl groups or similar groups which are attached to the ligand in the direction of the transition dipole moment. However, in the case of vacuum-processed triplet emitters, such substituents which have ensured orientation do not lead to significant orientation in the case of solution-processed triplet emitters, so that this idea cannot be directly applied to triplet emitters which are to be processed from solution. Complexes with acetylacetonate ligands also often lead to orientation in the case of vapor deposition, but not in the case of processing from solution.

[0005] The problem addressed by the present invention is to provide novel metal complexes which can be processed from solution and are suitable for use as emitters in OLEDs. One particular problem addressed is to provide emitters which lead to orientation and thus to an improvement of the external quantum efficiency of the OLED in the case of application from solution.

[0006] It has surprisingly been found that the binuclear iridium complexes substituted with linear long chain aromatic groups described below when processed from solution lead to orientation and thus to a significant improvement of the external quantum efficiency of OLEDs. The present invention thus provides these complexes and organic electroluminescent devices comprising these complexes.

[0007] The present invention provides a compound of formula (1),

[0008]

[0009] formula (1)

[0010] The symbols and indices used are as follows:

[0011] X is the same or different at each occurrence and is a group of formula -(Ar) n -R;

[0012] Y is the same or different at each occurrence and is R or X;

[0013] Z is the same or different and is R or X;

[0014] Ar is the same or different at each occurrence and is a divalent group selected from structures (Ar1) to (Ar7),

[0015]

[0016] wherein the dotted bond indicates the attachment of the unit, and V is CR2, O, S or NR;

[0017] n is the same or different at each occurrence and is an integer from 3 to 20, with the proviso that in each -(Ar) n -R unit at least 5 phenyl and / or cyclohexyl groups are attached to each other in a linear fashion;

[0018] R can occur one or more times and is the same or different at each occurrence and is: H, D, F, Cl, Br, I, N(R 1 )2, CN, NO2, OR 1 , SR 1 , COOH, C(=O)N(R 1 )2, Si(R 1 )3, B(OR 1 )2, C(=O)R 1 , P(=O)(R 1 )2, S(=O)R 1 , S(=O)2R 1 , OSO2R 1linear alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group can in each case be substituted by one or more R 1 groups, where one or more non-adjacent CH2groups can be replaced by Si(R 1 )2, C=0, NR 1 , O, S or CONR 1 , or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms which can in each case be substituted by one or more R 1 groups; it is also possible for two R

[0019] R 1 is in each case identical or different and is: H, D, F, Cl, Br, I, N(R 2 )2, CN, N02, OR 2 , SR 2 , Si(R 2 )3, B(OR 2 )2, C(=0)R 2 , P(=0)(R 2 )2, S(=0)R 2 , S(=0)2R 2 , OS02R 2 , a linear alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group can in each case be substituted by one or more R 2 groups, where one or more non-adjacent CH2groups can be replaced by Si(R 2 )2, C=0, NR 2 , O, S or CONR 2 , or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms which can in each case be substituted by one or more R 2 groups; it is also possible for two or more R 1 groups to form a ring system;

[0020] R 2 is in each case identical or different and is: H, D, F, or an aliphatic, aromatic or heteroaromatic organic group having 1 to 20 carbon atoms, in particular a hydrocarbyl group, where one or more hydrogen atoms can also be replaced by F.

[0021] A characteristic feature of the compounds of the present application is the presence of two X groups, which are aromatic or heteroaromatic groups or cyclic aliphatic groups connected in a linear fashion. Herein the "condition that in each -(Ar) n The "condition that in each -(Ar)

[0022] When two R or R 1 groups together form a ring system, it can be a monocyclic or polycyclic aliphatic, heteroaliphatic, aromatic or heteroaromatic. In this case, the groups together forming the ring system can be adjacent, which means that these groups are bound to the same carbon atom or to carbon atoms which are directly bound to each other, or they can be further apart from each other. Preferably, such a ring is formed in groups which are directly bound to each other or to the same carbon atom.

[0023] In the context of the present specification, the expression that two or more groups can together form a ring is to be understood in particular as that the two groups are connected to each other by a chemical bond under the condition that formally two hydrogen atoms are eliminated. This is exemplified by the following way:

[0024]

[0025] However, in addition, the above expression is to be understood as meaning that if one of the two groups is hydrogen, the second group is bound in the position where the hydrogen atom is bound, forming a ring. This is exemplified by the following way:

[0026]

[0027] The formation of an aromatic or heteroaromatic ring system is exemplified by the following way:

[0028]

[0029] In the context of this invention, an aryl group contains 6 to 40 carbon atoms; in the context of this invention, a heteroaryl group contains 2 to 40 carbon atoms and at least one heteroatom, provided that the sum of the carbon atoms and the heteroatom is at least 5. The heteroatom is preferably selected from N, O, and / or S. Here, aryl group or heteroaryl group should be understood to mean: a simple aromatic ring, i.e., benzene; or a simple heteroaromatic ring, such as pyridine, pyrimidine, thiophene, etc.; or a fused aryl or heteroaryl group, such as naphthalene, anthracene, phenanthrene, quinoline, isoquinoline, etc.

[0030] In the context of this invention, an aromatic ring system contains 6 to 40 carbon atoms. In the context of this invention, a heteroaromatic ring system contains 1 to 40 carbon atoms and at least one heteroatom, provided that the total number of carbon atoms and heteroatoms is at least 5. The heteroatom is preferably selected from N, O, and / or S. In the context of this invention, an aromatic or heteroaromatic ring system should be understood to mean a system that does not necessarily contain only aryl or heteroaromatic groups, but in which multiple aryl or heteroaromatic groups may also be interrupted by non-aromatic units (preferably less than 10% of atoms other than H) such as carbon, nitrogen, or oxygen atoms, or carbonyl groups. Therefore, systems such as 9,9'-spirodifluorene, 9,9-diarylfluorene, triarylamines, diaryl ethers, piracene, etc., should also be considered aromatic ring systems in the context of this invention, as should systems in which two or more aryl groups are interrupted by, for example, straight-chain or cyclic alkyl groups or silyl groups. In addition, systems in which two or more aryl or heteroaryl groups are directly bonded to each other, such as biphenyl, terphenyl, tetraphenyl, or bipyridine, should also be considered aromatic or heteroaryl ring systems. Aromatic or heteroaryl ring systems are preferably systems in which two or more aryl or heteroaryl groups are directly linked to each other by single bonds, or systems containing fluorene, spirodifluorene, or another aryl or heteroaryl group using an optionally substituted indene group, such as indobenzotriazole.

[0031] In the context of this invention, the term "alkyl group" is used as a general term for straight-chain, branched, and cyclic alkyl groups. Similarly, the terms "alkenyl group" and "alkynyl group" are used as general terms for straight-chain, branched, and cyclic alkenyl and alkynyl groups, respectively.

[0032] In the context of this invention, individual hydrogen atoms or CH2 groups may also be replaced by the aforementioned groups in C1- to C2-. 20- an alkyl group is understood to mean, for example, a methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, 2-methylbutyl, n-pentyl, sec-pentyl, tert-pentyl, 2-pentyl, neopentyl, cyclopentyl, n-hexyl, sec-hexyl, tert-hexyl, 2-hexyl, 3-hexyl, neohexyl, cyclohexyl, 1 -methylcyclopentyl, 2-methylpentyl, n-heptyl, 2-heptyl, 3-heptyl, 4-heptyl, cycloheptyl, 1 -methylcyclohexyl, n-octyl, 2-ethylhexyl, cyclooctyl, 1 -bicyclo[2.2.2]octyl, 2-bicyclo[2.2.2]octyl, 2-(2,6-dimethyl)octyl, 3-(3,7-dimethyl)octyl, adamantyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, 1,1 -dimethyl-n-hex-1 -yl, 1,1 -dimethyl-n-hept-1 -yl, 1,1 -dimethyl-n-oct-1 -yl, 1,1 -dimethyl-n-dec-1 -yl, 1,1 -dimethyl-n-dodec-1 -yl, 1,1 -dimethyl-n-tetradec-1 -yl, 1,1 -dimethyl-n-hexadec-1 -yl, 1,1 -dimethyl-n-octadec-1 -yl, 1,1 -diethyl-n-hex-1 -yl, 1,1 -diethyl-n-hept-1 -yl, 1,1 -diethyl-n-oct-1 -yl, 1,1 -diethyl-n-dec-1 -yl, 1,1 -diethyl-n-dodec-1 -yl, 1,1 -diethyl-n-tetradec-1 -yl, 1,1 -diethyl-n-hexadec-1 -yl, 1,1 -diethyl-n-octadec-1 -yl, 1 -(n-propyl)cyclohex-1 -yl, 1 -(n-butyl)cyclohex-1 -yl, 1 -(n-hexyl)cyclohex-1 -yl, 1 -(n-octyl)cyclohex-1 -yl and 1 -(n-decyl)cyclohex-1 -yl groups. An alkenyl group is understood to mean, for example, an ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl or cyclooctadienyl group. An alkynyl group is understood to mean, for example, an ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl or octynyl group. As for OR 1 or OR 2 C1- to C 20 - an alkoxy group is understood to mean, for example, a methoxy, trifluoromethoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy or 2-methylbutoxy group.

[0033] Aromatic or heteroaromatic ring systems having 5 to 40 aromatic ring atoms and which in each case can also be substituted by the abovementioned radicals and which can be attached to the aromatic or heteroaromatic system in any desired position are to be understood as meaning, for example, radicals derived from benzene, naphthalene, anthracene, benzanthracene, phenanthrene, benzophenanthrene, pyrene, chrysene, perylene, fluoranthene, benzofluoranthene, tetracene, pentacene, benzopyrene, biphenyl, binaphthyl, terphenyl, bitolyl, fluorene, spirobifluorene, dihydrophenanthrene, dihydro- pyrene, tetrahydro-pyrene, cis- or trans-indenofluorene, cis- or trans-monobenzoindenofluorene, cis- or trans-dibenzoindenofluorene, truxene, isotruxene, spirotruxene, spiroisotruxene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, indolocarbazole, indenocarbazole, pyridine, quinoline, isoquinoline, acridine, phenanthridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, phenothiazine, phenoxazine, pyrazole, indazole, imidazole, benzoimidazole, naphthimidazole, phenanthrolimidazole, pyridylimidazole, pyrazinylimidazole, quinoxalimida- zole,

[0034] ​​​​​​​​​​​​For the sake of example, in the following a compound of the present application is described in detail: the compound contains a pyrimidine group which is coordinated to one iridium via each of the two nitrogen atoms. Two phenyl groups are bound to the pyrimidine, each of which is coordinated to one of the two iridium atoms. Bound to each of the two phenyl groups is a 1,3,5-tris(o-phenyl)phenyl group, each of which constitutes a bridgehead of the polypodal complex. There are also two further optionally substituted phenylpyridine subligands, each of which is bound to the 1,3,5-tris(o-phenyl)phenyl groups. Thus, each of the two iridium atoms is coordinated to two phenylpyridine subligands and one phenylpyrimidine subligand, wherein the pyrimidine group is coordinated to both iridium atoms.

[0035] The term "subligand" in the context of the present application with respect to the two phenylpyridine ligands means that, if the 1,3,5-tris(o-phenyl)phenyl groups were not present, this would be a bidentate ligand. However, due to the formal abstraction of the hydrogen atoms on the phenylpyridines and the attachment to the 1,3,5-tris(o-phenyl)phenyl groups, the subligand is not a single ligand, but part of a dodecidentate ligand, whereby it occurs, i.e. the ligand has a total of 12 coordination sites, and therefore the term "subligand" is used.

[0036] The bond by which the ligand is attached to iridium can be a coordinate bond or a covalent bond, or the covalent part of the bond can vary depending on the ligand. When in the present application a ligand or subligand is mentioned to be coordinated or bound to Ir, this means in the context of the present application any type of attached bond of the ligand or subligand to Ir, regardless of the covalent part of the bond.

[0037] One preferred embodiment of the present application is a compound of the following formula (1 a),

[0038]

[0039] wherein the symbols used have the definitions given above.

[0040] In one preferred embodiment of the present application, the two substituents X are identical.

[0041] In one embodiment of the present application, Y and Z are H. In another embodiment of the present application, each Y group is a group of the formula -(Ar) n a group of the formula -R, which can be the same or different from the X groups. n a group of the formula -R, which can be the same or different from the X groups.

[0042] Thus, preferred embodiments of formula (1 ) or (1 a) are structures of the following formulae (1 a-1 ), (1 a-2) or (1 a-3),

[0043]

[0044]

[0045] wherein the two groups X each are identical and wherein the Y groups in formula (1a-2) each are -(Ar) n the -R groups and are identical and wherein the Z groups in formula (1a-3) are -(Ar) n the -R groups. Particularly preferred are compounds of formula (1a-1).

[0046] -(Ar) n The R groups in the -R groups are preferably identical or different in each case and are H, a linear alkyl group having 1 to 10 carbon atoms or a branched or cyclic alkyl group having 3 to 10 carbon atoms, in particular H.

[0047] In the following preferred Ar groups forming the structures X and additionally optional Y and Z are listed. As mentioned above, they are the bivalent structures (Ar1) to (Ar7), which can each be identical or different. Common to the (Ar1) to (Ar7) groups is that they are connected via the para position, or in formula (Ar3) via a connection analogous to the para position, leading to a linear connection of the units within the X or Y or Z group. This is necessary because only then the compounds of the present application will show an orientation upon deposition from solution.

[0048] Preferred embodiments of structure (Ar1) are the following structures (Ar1a) to (Ar1f),

[0049]

[0050] wherein the dotted bond indicates the connection of the structure, W is C(R 1 )2, O, S or NR 1 and R and R 1 have the definitions given above. W here is preferably O or S.

[0051] The preferred substituents R in structures (Ar1b) to (Ar1d) are identical or different in each case and are selected from the group consisting of a linear alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, each of which can be substituted by one or more R 1 groups, but preferably are unsubstituted; or an aromatic ring system having 6 to 12 aromatic ring atoms and which can be substituted by one or more R 1 groups, wherein R 1 is preferably a linear alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms; or OR1 R is a linear alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms. 1 R is a linear alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms.

[0052] R is a linear alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms. 1 R is a linear alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms. 1 R is a linear alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms. 1 R is a linear alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms. 1 R is a linear alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms.

[0053] Preferred embodiments of structure (Ar2) are structures (Ar2a) and (Ar2b),

[0054]

[0055] wherein the dotted bond denotes the attachment of the structure, and R and V have the definitions given above.

[0056] Particularly preferred embodiments of structure (Ar2) are structures (Ar2a-1) to (Ar2a-5) and (Ar2b-1),

[0057]

[0058] wherein the dotted bond denotes the attachment of the structure, and R and R 1 have the definitions given above.

[0059] The preferred substituents R in structures (Ar2a-1) and (Ar2b-1) are in each case identical or different and are selected from the group consisting of a linear alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, each of which can be substituted by one or more R 1 groups, but are preferably unsubstituted; or an aromatic ring system having 6 to 12 aromatic ring atoms which can be substituted by one or more R 1 groups, wherein R 1 is a linear alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms.

[0060] The preferred substituents R 1 in structure (Ar2a-2) are in each case identical or different and are selected from the group consisting of H; a linear alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, each of which can be substituted by one or more R2 the group R is preferably not substituted.

[0061] The preferred substituents R in structure (Ar2a-5) are identical or different in each case and are selected from the group consisting of linear alkyl radicals having 1 to 20 carbon atoms or branched or cyclic alkyl radicals having 3 to 20 carbon atoms, each of which can be substituted by one or more R 1 aromatic or heteroaromatic ring systems, preferably having 6 to 12 aromatic ring atoms, which can be substituted by one or more R 1 aromatic ring systems, wherein R 1 is preferably a linear alkyl radical having 1 to 20 carbon atoms or a branched or cyclic alkyl radical having 3 to 20 carbon atoms.

[0062] A preferred embodiment of structure (Ar3) is the following structure (Ar3a),

[0063]

[0064] wherein the dotted bond denotes the linking of the structure.

[0065] A preferred embodiment of structure (Ar4) is the following structures (Ar4a) and (Ar4b),

[0066]

[0067] wherein the dotted bond denotes the linking of the structure and R has the definition given above.

[0068] The preferred substituents R in structure (Ar4b) are identical or different in each case and are selected from the group consisting of linear alkyl radicals having 1 to 20 carbon atoms or branched or cyclic alkyl radicals having 3 to 20 carbon atoms, each of which can be substituted by one or more R 1 aromatic or heteroaromatic ring systems, preferably having 6 to 12 aromatic ring atoms, which can be substituted by one or more R 1 aromatic ring systems, wherein R 1 is preferably a linear alkyl radical having 1 to 20 carbon atoms or a branched or cyclic alkyl radical having 3 to 20 carbon atoms.

[0069] A preferred embodiment of structure (Ar5) is the following structures (Ar5a) and (Ar5b),

[0070]

[0071] wherein the dotted bond denotes the linking of the structure and R has the definition given above.

[0072] Preferred substituents R in structure (Ar5b) are identical or different in each case and are selected from the group consisting of: H; a linear alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, each of which can be substituted by one or more R 1 groups, but are preferably unsubstituted.

[0073] A preferred embodiment of structure (Ar7) is structure (Ar7a),

[0074]

[0075] wherein the dotted bond denotes the attachment of the structure.

[0076] In a preferred embodiment of the present application, at least one Ar group, more preferably at least two Ar groups, most preferably at least 3 Ar groups, are identical or different in each case and are selected from structure (Ar1 ) and / or (Ar2). It is particularly preferred that all Ar groups are selected from structure (Ar1 ) and / or (Ar2). Structure (Ar1 ) is preferably identical or different in each case and is selected from structure (Ar1 a) to (Ar1 d), and structure (Ar2) is selected from structure (Ar2a), more preferably structure (Ar2a-1 ).

[0077] When R or R 1 groups in structures (Ar1 ) to (Ar7) or the above-mentioned preferred structures are linear, branched or cyclic alkyl groups, said alkyl groups preferably have 1 to 15 carbon atoms, more preferably 1 to 12 carbon atoms and most preferably 1 to 10 carbon atoms. As substituents R or R 1Examples of suitable alkyl groups are methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, 2-methylbutyl, n-pentyl, sec-pentyl, tert-pentyl, 2-pentyl, neopentyl, cyclopentyl, n-hexyl, sec-hexyl, tert-hexyl, 2-hexyl, 3-hexyl, neohexyl, cyclohexyl, 1 -methylcyclopentyl, 2-methylpentyl, n-heptyl, 2-heptyl, 3-heptyl, 4-heptyl, cycloheptyl, 1 -methylcyclohexyl, n-octyl, 2-ethylhexyl, cyclooctyl, 1 -bicyclo[2.2.2]octyl, 2-bicyclo[2.2.2]octyl, 2-(2,6-dimethyl)octyl, 3-(3,7-dimethyl)octyl, adamantyl, 1,1 -dimethyl-n-hex-1 -yl, 1,1 -dimethyl-n-hept-1 -yl, 1,1 -dimethyl-n-oct-1 -yl, 1,1 -dimethyl-n-dec-1 -yl, 1,1 -dimethyl-n-dodec-1 -yl, 1,1 -dimethyl-n-tetradec-1 -yl, 1,1 -dimethyl-n-hexadec-1 -yl, 1,1 -dimethyl-n-octadec-1 -yl, 1,1 -diethyl-n-hex-1 -yl, 1,1 -diethyl-n-hept-1 -yl, 1,1 -diethyl-n-oct-1 -yl, 1,1 -diethyl-n-dec-1 -yl, 1,1 -diethyl-n-dodec-1 -yl, 1,1 -diethyl-n-tetradec-1 -yl, 1,1 -diethyl-n-hexadec-1 -yl, 1,1 -diethyl-n-octadec-1 -yl, 1 -(n-propyl)cyclohex-1 -yl, 1 -(n-butyl)cyclohex-1 -yl, 1 -(n-hexyl)cyclohex-1 -yl, 1 -(n-octyl)cyclohex-1 -yl and 1 -(n-decyl)cyclohex-1 -yl. The alkyl groups can also each have one or more stereocenters, in which case the structure of the pure enantiomer or the pure diastereomer or the corresponding racemate can be used.

[0078] As mentioned above, n is an integer from 3 to 20, with the proviso that at least 5 phenyl or cyclohexane groups are connected to each other in a linear fashion. In a preferred embodiment of the present application, n is an integer from 5 to 20, in particular from 5 to 15. More preferably, n is chosen such that in total 8 to 24 phenyl or cyclohexane groups, more preferably 12 to 24 phenyl or cyclohexane groups and most preferably 15 to 20 phenyl or cyclohexane groups are connected to each other in a linear fashion. As mentioned above, the structures (Ar2), (Ar4) and (Ar5) each contribute two phenyl groups.

[0079] In the following, preferred embodiments of the phenylpyridine subligand are described. When the phenylpyridine subligand in formula (1 ) is substituted by one or more R groups, these substituents are preferably bound as shown in formula (2),

[0080]

[0081] wherein the symbols used have the definitions detailed above.

[0082] The same preferences for the position of the R groups on the phenylpyridine subligand also apply to the preferred structures.

[0083] Preferred are structures of the following formula (2a),

[0084]

[0085] wherein the symbols used have the definitions given above.

[0086] For the substituents on the phenylpyridine subligand, it is preferred that each of the four subligands has the same substitution. It is also preferred that each phenylpyridine subligand has at most three, more preferably at most two substituents R which are not H. When two substituents R which are not H are bound to the pyridine ring, it is preferred that at least one of the two substituents is an alkyl group. More preferably, no more than one substituent R on the pyridine is a group other than H. In another preferred embodiment of the present application, the phenyl group of the phenylpyridine subligand contains a substituent R bound in para position to the iridium, wherein this substituent R is preferably selected from an aromatic ring system having 6 to 24 aromatic ring atoms, preferably 6 to 12 aromatic ring atoms, and each can be substituted by one or more R 1 groups, wherein R 1 is preferably selected from a linear alkyl group having 1 to 10 carbon atoms or a branched or cyclic alkyl group having 3 to 10 carbon atoms, wherein R is especially an unsubstituted phenyl group. In another preferred embodiment of the present application, the pyridine group of the phenylpyridine subligand contains a substituent R bound in para position to the nitrogen atom, wherein this substituent R is preferably selected from a linear alkyl group having 1 to 10 carbon atoms or a branched or cyclic alkyl group having 3 to 10 carbon atoms, especially a methyl group.

[0087] The R groups on the phenylpyridine subligand of formula (1) or the preferred embodiments are preferably identical or different in each case and are selected from the group consisting of: H, D, F, OR 1 , CN, a linear alkyl group having 1 to 10 carbon atoms or a branched or cyclic alkyl group having 3 to 10 carbon atoms, wherein each alkyl group can be substituted by one or more R 1 groups, or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms and in each case can be substituted by one or more R 1 groups; while two adjacent R groups can also together form a mono- or polycyclic aliphatic or aromatic ring system. More preferably, these R groups are identical or different in each case and are selected from the group consisting of: H, D, F, OR 1A straight-chain alkyl group having 1 to 6 carbon atoms or a branched or cyclic alkyl group having 3 to 10 carbon atoms, wherein one or more hydrogen atoms may be replaced by D or F, or having 5 to 24 aromatic ring atoms, preferably 6 to 13 aromatic ring atoms, and in each case may be replaced by one or more R atoms. 1 Aromatic or heteroaromatic ring systems with substituted groups; simultaneously, two adjacent R groups may also form monocyclic or polycyclic aliphatic or aromatic ring systems. Particularly preferred aromatic ring systems are: phenyl groups, which may also be substituted with one or two alkyl groups each having 1 to 6 carbon atoms; or biphenyl groups.

[0088] Preferred R bonded to R 1 The groups may be the same or different in each case and are: 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, wherein each alkyl group may be represented by one or more R 2 Group substitution, or having 5 to 24 aromatic ring atoms and in each case being substituted with one or more R groups. 2 Aromatic or heteroaromatic ring systems with substituted groups; simultaneously, two or more adjacent R groups... 1 The groups can together form monocyclic or polycyclic aliphatic ring systems. A particularly preferred R is the one bonded to R. 1 The groups may be the same or different in each case and are: H, F, CN, straight-chain alkyl groups having 1 to 5 carbon atoms or branched or cyclic alkyl groups having 3 to 5 carbon atoms, each of which may be represented by one or more R 2 Group substitution, or having 5 to 13 aromatic ring atoms and in each case being substituted with one or more R groups. 2 Aromatic or heteroaromatic ring systems with substituted groups; simultaneously, two or more adjacent R groups... 1 The groups can work together to form monocyclic or polycyclic aliphatic ring systems.

[0089] Preferred R 2 The groups may be the same or different in each case and are: H, F, or an aliphatic hydrocarbon group having 1 to 5 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms; simultaneously, two or more R 2 Substituents can also form monocyclic or polycyclic aliphatic ring systems together.

[0090] Within the scope of the claims, the above preferred embodiments can be combined with each other as needed. In a particularly preferred embodiment of the invention, the above preferred embodiments are applied simultaneously.

[0091] The compounds of this invention have a chiral structure. Depending on the exact structure of the complex and ligands, diastereomers and several pairs of enantiomers can be formed.

[0092] In this case, the complexes of the application comprise mixtures of different diastereomeric or corresponding racemic pairs and also the individual isolated diastereomers or enantiomers. Diastereomeric pairs can be separated by customary methods, for example by chromatography or by fractional crystallization. The separation of racemates can be carried out by fractional crystallization of the diastereomeric pairs of salts or by customary methods on chiral columns.

[0093] In the following, examples of suitable compounds of the application are cited. In these example structures, the X group has the general structure as follows:

[0094]

[0095] The structures 1 to 34 cited below are suitable for A1to A 10 of the structures in the following table have a hydrogen atom instead of the dotted bond. The asymmetric groups (groups 3, 4, 6, 9, 10 and 18) can be connected to the preceding group by either of the two dotted bonds. For greater clarity, only one isomer form is given in these cases. n

[0096]

[0097]

[0098]

[0099] The suitable X groups shown in the following table can be constructed from the structures 1 to 34 shown above:

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107] For example, these X groups shown above can be connected by the dotted bond to the following double metal complex:

[0108]

[0109] ​

[0110]

[0111]

[0112] H1 to H10 in the above table are each connected to the X group by two dotted lines. All X groups shown above can be connected to any one of the complexes H1 to H10. As an example, for H1 and the groups X1 to X285 in the following table, they are shown in the following table:

[0113]

[0114]

[0115]

[0116]

[0117] The complexes of the application can be prepared, inter alia, by the routes described below. To this end, 12-dentate ligands are prepared which do not contain the X and optionally Y and / or Z groups, but in each case contain a reactive leaving group, which is then coordinated to the iridium metal by an ortho-metalation reaction. Alternatively, the metal complex can also be synthesized first, still without any reactive leaving group, and the reactive leaving group is then introduced into the complex. Suitable reactive leaving groups are, for example: halogen, in particular chlorine, bromine or iodine; triflate; tosylate; or boronic acid derivatives, such as boronic acids or boronic acid esters. The X and optionally Y and / or Z groups can then be reacted by coupling reactions with compounds A-(Ar) n -R, wherein A is a reactive leaving group, for example: halogen, in particular chlorine, bromine or iodine; triflate; tosylate; or boronic acid derivatives, such as boronic acids or boronic acid esters. In general, all C-C coupling reactions are suitable for this, in particular the Suzuki coupling. Such reactions are known to the person skilled in the art, who will have no difficulty in applying these reactions to the compounds of the application.

[0118] The application therefore also provides a process for preparing a compound of the application by reacting a compound which is substituted by a reactive leaving group instead of X and optionally Y and / or Z with a compound A-(Ar) n -R, wherein A is a reactive leaving group. This reaction is preferably a Suzuki coupling.

[0119] For processing the compounds of the present application, for example, from the liquid phase by spin coating or by printing methods, formulations of the compounds of the present application are required. These formulations can be, for example, solutions, dispersions or emulsions. For this purpose, it can be preferred to use a mixture of two or more solvents. The solvents are selected from the group consisting of hydrocarbons, alcohols, esters, ethers, ketones and amines. Suitable preferred solvents are selected from, for example, toluene, anisole, o-, m- or p-xylene, methyl benzoate, methylene, tetraline, veratrol, THF, methyl-THF, THP, chlorobenzene, dodecane, phenoxytoluene, in particular 3-phenoxytoluene, (-)-fenchone, 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, 1 -methylnaphthalene, 1 -ethylnaphthalene, decylbenzene, phenylnaphthalene, menthyl isovalerate, p-cresyl isobutyrate, cyclohexyl hexanoate, ethyl p-toluate, ethyl o-toluate, ethyl m-toluate, tetraline, ethyl 2-methoxybenzoate, dibutylbenzene, dicyclohexanone, isosorbide dimethyl ether, tetraline, 2-methylbiphenyl, ethyl octanoate, octyl octanoate, diethyl sebacate, 3,3-dimethylbiphenyl, 1,4-dimethylnaphthalene, 2,2'-dimethylbiphenyl, 2-methylbenzothiazole, 2-phenoxyethanol, 2-pyrrolidone, 3-methyl anisole, 4-methyl anisole, 3,4-dimethyl anisole, 3,5-dimethyl anisole, acetophenone, α-terpineol, benzothiazole, butyl benzoate, cumene, cyclohexanol, cyclohexanone, cyclohexylbenzene, tetraline, dodecylbenzene, ethyl benzoate, indane, NMP, p-cymene, phenetole, 1,4-diisopropylbenzene, benzyl 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-isopropyl naphthalene, amylbenzene, hexylbenzene, heptylbenzene, octylbenzene, 1,1 -bis(3,4-dimethylphenyl)ethane, or a mixture of these solvents.

[0120] The present application therefore also provides a formulation comprising at least one compound of the present application and at least one further compound. The further compound may, for example, be a solvent, in particular one of the solvents mentioned above or a mixture of these solvents. The further compound may, alternatively, be a further organic or inorganic compound which is likewise used in electronic devices, for example a matrix material. This further compound can also be polymeric.

[0121] The compounds of the present application described above or the preferred embodiments detailed above can be used as active components in electronic devices. The present application therefore also provides the use of a compound of the present application in an electronic device. The present application also additionally provides an electronic device comprising at least one compound of the present application.

[0122] ​An electronic device is understood to mean any device which comprises an anode, a cathode and at least one layer which comprises at least one organic or organometallic compound. The electronic device according to the application thus comprises an anode, a cathode and at least one layer which comprises at least one compound according to the application. Preferred electronic devices are selected from the group consisting of organic electroluminescent devices (OLED, PLED), organic infrared electroluminescent sensors, organic integrated circuits (O-IC), organic field effect transistors (O-FET), organic thin-film transistors (O-TFT), organic light-emitting transistors (O-LET), organic solar cells (O-SC) (the latter is understood to mean pure organic solar cells and dye-sensitised solar cells batteries), organic optical detectors, organic photoreceptors, organic field-quench devices (O-FQD), light-emitting electrochemical cells (LEC), oxygen sensors and organic laser diodes (O-laser), which comprise at least one compound according to the application in at least one layer. Particular preference is given to organic electroluminescent devices. Active components are generally organic or inorganic materials which are introduced between the anode and the cathode, such as charge-injection, charge-transport or charge-blocking materials, but especially light-emitting materials and matrix materials. The compounds according to the application exhibit particularly good properties as light-emitting materials in organic electroluminescent devices. The preferred embodiment of the application is thus an organic electroluminescent device.

[0123] An organic electroluminescent device comprises a cathode, an anode and at least one light-emitting layer. In addition to these layers, it can also comprise further layers, such as, in each case, one or more hole-injection layers, hole-transport layers, hole-blocking layers, electron-transport layers, electron-injection layers, exciton-blocking layers, electron-blocking layers, charge-generation layers and / or organic or inorganic p / n junctions. It is also possible for one or more hole-transport layers to be p-doped, for example with metal oxides such as Mo03or W03or with (per)fluorinated electron-deficient aromatic systems, and / or for one or more electron-transport layers to be n-doped. It is likewise possible to introduce interlayers between two light-emitting layers, which have, for example, an exciton-blocking function and / or control the charge balance in the electroluminescent device. It should be noted, however, that not all of these layers necessarily have to be present.

[0124] In this case, the organic electroluminescent device can comprise one emitting layer, or it can comprise a plurality of emitting layers. If a plurality of emitting layers is present, these emitting layers preferably together have several emission maxima between 380 nm and 750 nm such that the overall result is white emission; in other words, a plurality of luminescent compounds which can emit fluorescence or phosphorescence is used in the emitting layers. Particularly preferred are: three-layer systems in which the three layers exhibit blue, green and orange or red emission (for the basic construction, see, for example, WO 2005 / 011013); or systems having more than three emitting layers. The system can also be a hybrid system in which one or more layers emit fluorescence and one or more other layers emit phosphorescence. White-emitting organic electroluminescent devices can be used in lighting applications or together with colour filters for full-colour displays. It is also possible to achieve white-emitting OLEDs by means of tandem OLEDs. Furthermore, it is also possible to achieve white-emitting OLEDs in such a way that two or more emitters which emit different colours of light are present in the emitting layer, one of which is a compound according to the application, such that the light emitted from the individual emitters adds up to white light.

[0125] In a preferred embodiment of the application, the organic electroluminescent device comprises a compound according to the application as luminescent compound in one or more emitting layers.

[0126] Many of the compounds according to the application emit in the red spectral region. However, by suitable selection of the ligands and substitution pattern, it is also possible to shift the emission into the infrared region, or to effect a blue shift, preferably into the orange or yellow region.

[0127] When the compounds according to the application are used as luminescent compounds in the emitting layer, use in combination with one or more matrix materials is preferred; the terms "matrix material" and "host material" are used synonymously hereinafter. The mixture of the compound according to the application and the matrix material contains, based on the total mixture of emitters and matrix material, from 0.1 to 99% by weight, preferably from 3 to 90% by weight, more preferably from 5 to 40% by weight and particularly from 10 to 25% by weight of the compound according to the application. Correspondingly, the mixture contains, based on the total mixture of emitters and matrix material, from 99.9 to 1 % by weight, preferably from 97 to 10% by weight, more preferably from 95 to 60% by weight and particularly from 90 to 75% by weight of the matrix material.

[0128] The matrix material used can generally be any material known from the prior art for this purpose. The triplet level of the matrix material is preferably higher than the triplet level of the emitters.

[0129] Suitable matrix materials for the compounds according to the application are, for example, ketones, phosphinoxides, sulfoxides and sulfones according to WO 2004 / 013080, WO 2004 / 093207, WO 2006 / 005627 or WO 2010 / 006680; triaryl amines, carbazole derivatives, for example CBP (N,N-dicarbazolylbiphenyl), m-CBP or carbazole derivatives disclosed in WO 2005 / 039246, US 2005 / 0069729, JP 2004 / 288381, EP 1205527, WO 2008 / 086851 or US 2009 / 0134784; indolocarbazole derivatives, for example according to WO 2007 / 063754 or WO 2008 / 056746; indenocarbazole derivatives, for example according to WO 2010 / 136109 or WO 2011 / 000455; azacarbazoles, for example according to EP 1617710, EP 1617711, EP 1731584, JP 2005 / 347160; ambipolar matrix materials, for example according to WO 2007 / 137725; silanes, for example according to WO 2005 / 111172; borazoles or boron esters, for example according to WO 2006 / 117052; silaazacyclopentanes, for example according to WO 2010 / 054729; phosphaazacyclopentanes derivatives, for example according to WO 2010 / 054730; triazine derivatives, for example according to WO 2010 / 015306, WO 2007 / 063754 or WO 2008 / 056746; zinc complexes, for example according to EP 652273 or WO 2009 / 062578; dibenzofuran derivatives, for example according to WO 2009 / 148015 or WO 2015 / 169412; carbazol amines or bridged carbazole derivatives, for example according to US 2009 / 0136779, WO 2010 / 050778, WO 2011 / 042107 or WO 2011 / 088877.

[0130] It can also be preferred to use a plurality of different matrix materials as a mixture, in particular at least one electron-conducting matrix material and at least one hole-conducting matrix material. Preferred combinations are, for example, the use of a triazine, pyrimidine, quinazoline or quinoxaline derivative with a triarylamine derivative or a carbazole derivative as a mixed matrix for the metal complex of the application. It is likewise preferred to use a mixture of a charge-transporting matrix material and an electrically inert matrix material, which does not significantly participate in charge transport, even if it does participate in charge transport, as described, for example, in WO 2010 / 108579 or WO 2016 / 184540. It is likewise preferred to use two electron-transporting matrix materials, for example a triazine derivative and a lactam derivative, as described, for example, in WO 2014 / 094964.

[0131] Described below are examples of compounds which are suitable as matrix materials for the compounds of the application.

[0132] Preferred electron-transporting matrix materials are selected from triazine derivatives, pyrimidine derivatives, quinazoline derivatives and quinoxaline derivatives. Preferred triazine, pyrimidine, quinazoline or quinoxaline derivatives which can be used as a mixture together with the compounds of the application are the compounds of the following formulae (19), (20), (21) and (22),

[0133]

[0134] in which R and R 1 have the definitions given above and Ar 1 are identical or different in each case and are an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms and can be substituted in each case by one or more R 1 groups.

[0135] Particular preference is given to triazine derivatives of the formula (19) and quinazoline derivatives of the formula (21), in particular triazine derivatives of the formula (19).

[0136] In a preferred embodiment of the application, Ar 1 are identical or different in each case and are an aromatic or heteroaromatic ring system having 6 to 30 aromatic ring atoms, in particular 6 to 24 aromatic ring atoms, and can be substituted by one or more R 1 groups.

[0137] Examples of suitable triazine compounds which can be used as matrix materials together with the compounds of the application are the compounds described in the following table:

[0138]

[0139]

[0140]

[0141]

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148] Examples of suitable quinazoline compounds are the compounds described in the following table:

[0149]

[0150]

[0151] Preferred bis-carbazoles are the structures of the following formulae (23) and (24),

[0152]

[0153] wherein Ar 1 and R have the definitions given above and A 1 is CR2, NR, O or S. In a preferred embodiment of the present application, A 1 is CR2.

[0154] Preferred embodiments of the compounds of formula (23) and (24) are the compounds of the following formulae (23a) and (24a),

[0155]

[0156]

[0157] wherein the symbols used have the definitions given above.

[0158] Examples of suitable compounds of formula (23) and (24) are the following compounds:

[0159]

[0160]

[0161]

[0162]

[0163]

[0164] Preferred bridged carbazoles are compounds of the following formula (25),

[0165]

[0166] wherein A 1 and R have the definitions given above and A 1 are preferably identical or different in each case and are selected from the group consisting of NAr 1 and CR2.

[0167] Preferred dibenzofuran derivatives are compounds of the following formula (26),

[0168]

[0169] wherein the oxygen can also be replaced by sulfur to form a dibenzothiophene, L is a single bond or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms and can also be substituted by one or more R groups, and R and Ar 1 have the definitions given above. It is also possible here for two Ar 1 groups bound to the same nitrogen atom or for one Ar 1 group and one L group bound to the same nitrogen atom to be bound to one another, for example to give a carbazole.

[0170] Examples of suitable dibenzofuran derivatives are the compounds described below.

[0171]

[0172]

[0173] Suitable compounds which can be used as wide-bandgap matrix materials are compounds of the following formula (27),

[0174]

[0175] wherein R has the definitions given above and is preferably identical or different in each case and is: H, D, a straight-chain alkyl group having 1 to 10 carbon atoms, a branched or cyclic alkyl group having 3 to 10 carbon atoms or an aromatic ring system having 6 to 24 aromatic ring atoms, which can also be substituted by one or more alkyl groups having 1 to 10 carbon atoms, but is preferably unsubstituted.

[0176] Examples of materials which can be used as wide-bandgap matrix materials:

[0177]

[0178]

[0179] It is also preferred to use mixtures of two or more triplet emitters, in particular two triplet emitters with one or more matrix materials. In this case, the triplet emitter with the shorter wavelength emission spectrum serves as co-matrix for the triplet emitter with the longer wavelength emission spectrum. In this case, typically, the compound of formula (1) is the triplet emitter with the longer wavelength emission maximum. For example, the compounds of the present application can be combined with metal complexes that emit at shorter wavelengths as co-matrix, for example blue, green or yellow emitting metal complexes.

[0180] A preferred mixture in the light-emitting layer comprises an electron-transporting host material, i.e. a so-called "wide band gap" host material, which, if it participates in the charge transport in the layer, does so to an insignificant extent due to its electronic properties, a co-dopant, which is a triplet emitter that emits at a shorter wavelength compared to the compound of the present application, and the compound of the present application.

[0181] A further preferred mixture in the light-emitting layer comprises an electron-transporting host material, i.e. a so-called "wide band gap" host material, which, if it participates in the charge transport in the layer, does so to an insignificant extent due to its electronic properties, a hole-transporting host material, a co-dopant, which is a triplet emitter that emits at a shorter wavelength compared to the compound of the present application, and the compound of the present application.

[0182] Examples of the aforementioned emitters can be found in the following 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 / 041769, WO 2019 / 020538, WO 2018 / 178001, WO 2019 / 115423 and WO 2019 / 158453. Generally, all phosphorescent complexes known from the state of the art and the technical field of organic electroluminescence for phosphorescent OLEDs are suitable and the skilled person will be able to use further phosphorescent complexes without inventive step.

[0183] Examples of suitable triplet emitters which can be used as co-dopant for the compounds of the present application are described in the following table.

[0184]

[0185]

[0186]

[0187] Preferred cathodes are metals, metal alloys or multilayer structures with low work function, which comprise a plurality of metals, such as alkaline earth metals, alkali metals, main group metals or lanthanides (for example Ca, Ba, Mg, Al, In, Mg, Yb, Sm, etc.). Also suitable are alloys comprising alkali or alkaline earth metals and silver, for example alloys comprising magnesium and silver. In the case of multilayer structures, it is also possible to use other metals having a relatively high work function, such as Ag, in addition to the said metals, in which case combinations of the said metals are generally used, for example Mg / Ag, Ca / Ag or Ba / Ag. It can also be preferred to introduce a thin intermediate layer of a material having a high dielectric constant between the metal cathode and the organic semiconductor. Examples of materials which can be used for this purpose are alkali metal or alkaline earth metal fluorides, but also the corresponding oxides or carbonates (for example LiF, Li20, BaF2, MgO, NaF, CsF, Cs2C03, etc.). Likewise, organic alkali metal complexes, such as LiQ (lithium quinolate), are used for this purpose. The layer thickness of this layer is preferably from 0.5 to 5 nm.

[0188] Preferred anodes are materials having a high work function. Preferably, the anode has a work function of greater than 4.5 eV relative to vacuum. Firstly, metals having a high redox potential, such as Ag, Pt or Au, are suitable for this purpose. Secondly, metal / metal oxide electrodes (for example Al / Ni / NiO x , Al / PtO x ) can also be preferred. For some applications, at least one of the electrodes must be transparent or partially transparent in order to be able to irradiate the organic material (O-SC) or to emit light (OLED / PLED, O-laser). Preferred anode materials here are conductive mixed metal oxides. Particular preference is given to indium tin oxide (ITO) or indium zinc oxide (IZO). Preference is also given to conductive doped organic materials, in particular conductive doped polymers, such as PEDOT, PANI or derivatives of these polymers. Preference is also given, when a p-doped hole-transport material is applied as hole-injection layer to the anode, to suitable p-type dopants in this case being: metal oxides, such as Mo03or W03; or (per)fluorinated electron-deficient aromatic systems. Other suitable p-type dopants are HAT-CN (hexacyanohexaazatriphenylene) or the compound NPD9 from Novaled. This layer simplifies the hole injection into materials having a low HOMO, i.e. materials having a large HOMO in terms of magnitude.

[0189] In the other layers, it is generally possible to use any material which is used for these layers according to the prior art, and the person skilled in the art is able to combine any of these materials with the materials of the application for use in electronic devices without inventive step.

[0190] The device is correspondingly structured, contact-connected and finally hermetically sealed (depending on the application), since the lifetime of such a device is greatly shortened in the presence of water and / or air.

[0191] It is also preferred that an organic electroluminescent device is characterized in that one or more layers are applied by sublimation. In this case, the material is applied by vapor deposition at an initial pressure of typically less than 10 -5 millibar, preferably less than 10 -6 millibar. It is also possible for the initial pressure to be even lower or higher, for example less than 10 -7 millibar.

[0192] It is likewise preferred that an organic electroluminescent device is characterized in that one or more layers are applied by OVPD (organic vapor phase deposition) or by means of carrier gas sublimation. In this case, the material is applied at a pressure of 10 -5 millibar to 1 bar. A special case of this method is the OVJP (organic vapor jet printing) method, in which the material is applied directly through a nozzle and thus structured.

[0193] It is furthermore preferred that an organic electroluminescent device is characterized in that one or more layers are produced from solution, for example by spin coating, or by any printing method such as screen printing, flexographic printing, offset printing or nozzle printing, but more preferably LITI (light induced thermal imaging, thermal transfer printing) or inkjet printing. For this purpose, soluble compounds which are obtained, for example, by appropriate substitution are required. In a preferred embodiment of the application, the layer comprising the compounds of the present application is applied from solution.

[0194] An organic electroluminescent device can also be produced as a hybrid process by applying one or more layers from solution and one or more further layers by vapor deposition. For example, an emission layer and a hole transport layer which contain the compounds of the present application and a matrix material can be applied from solution, and a hole-blocking layer and / or an electron transport layer can be applied by vapor deposition at reduced pressure.

[0195] These methods are generally known to the person skilled in the art and the person skilled in the art is able to apply said methods without any difficulty to an organic electroluminescent device comprising a compound of the formula (1) or to the preferred embodiments detailed above.

[0196] The electronic devices, in particular organic electroluminescent devices, of the present application are remarkable with respect to the prior art in that they are able to be applied in an oriented manner even in the case of application from solution, which leads to oriented luminescence and thus to an improved external quantum efficiency. Such an improvement is achieved in comparison with complexes which have the same structure in other respects but without any X groups. This advantageous technical effect is not accompanied by any deterioration of other electronic properties.

[0197] The application is illustrated in more detail by the following examples, which are in no way intended to limit the application. The person skilled in the art will be able to use the details provided to make further inventive electronic devices without inventive labour and thus to practise the application in its full scope. Example:

[0198] Unless indicated otherwise, the subsequent syntheses are carried out in anhydrous solvents under an atmosphere of protective gas. The metal complexes are additionally handled in the dark or under yellow light. Solvents and reagents can be purchased from, for example, Sigma-ALDRICH or A BCR. The respective number in square brackets or the number quoted for the individual compounds relates to the CAS number of a compound known from the literature.

[0199] Synthesis of X groups:

[0200]

[0201] Synthesis of B1

[0202] 26 g (33.7 mmol) of A1 (CAS 2171483-83-1) are dissolved in 600 ml of dichloromethane. Subsequently, 7.2 g (44 mmol) of N-bromosuccinimide are added in portions, a drop of HBr is added and the mixture is stirred at room temperature. After 48 hours, 200 ml of an aqueous sodium bisulfite solution (30%) are added and the mixture is stirred for 1 hour. Subsequently, the two phases are separated, the organic phase is extracted with water and then concentrated under reduced pressure. The residue is mixed with 300 ml of n-heptane and refluxed for 1 hour. After the mixture has cooled, the colourless solid is filtered off and dried under reduced pressure. Yield: 25.3 g (32 mmol), corresponding to 97% of the theoretical value.

[0203] The following compounds can likewise be prepared:

[0204]

[0205]

[0206]

[0207] Synthesis of C1:

[0208] To 28.0 g (35.5 mmol) of B1, 33.6 g (35.5 mmol) of CAS 2171483-74-0 and 9.8 g (71 mmol) of potassium carbonate, 1100 ml of THF and 550 ml of water are added. Subsequently, 373 mg (1.4 mmol) of triphenylphosphine and 325 mg (0.4 mmol) of tris(dibenzylideneacetone)dipalladium are added and the mixture is refluxed for 16 hours. Subsequently, water and toluene are added to the reaction mixture and the phases are separated. The aqueous phase is extracted twice with toluene and the combined organic phases are extracted once with water. The organic phase is filtered through aluminium oxide and then concentrated under reduced pressure. The product is purified by repeated crystallization from toluene / n-hexane 1 :10 and obtained in solid form. Yield: 41.0 g (28.8 mmol); 81% of theory.

[0209] The following compounds can be prepared analogously:

[0210]

[0211]

[0212]

[0213] Synthesis of D1:

[0214] To 25.3 g (18.7 mmol) of C1, 8.6 g (33.7 mmol) of bis(pinacolato)diboron, 5.5 g (56 mmol) of potassium acetate and 830 mg (1.1 mmol) of trans-dichlorobis(tricyclohexylphosphine)palladium(II) are added 750 ml of dioxane and the mixture is refluxed for 48 hours. Subsequently, toluene and water are added to the reaction mixture and the phases are separated. The aqueous phase is extracted twice with toluene and the combined organic phases are extracted twice with water, filtered through aluminium oxide and concentrated under reduced pressure. The residue is extracted by stirring with hot ethanol, obtaining the product in solid form. Yield: 16.0 g (11.1 mmol), 60% of theory.

[0215] The following compounds can be prepared analogously:

[0216]

[0217]

[0218]

[0219] Synthesis of E1:

[0220] ​To 5 g (6.4 mmol) of B1, 9.8 g (6.8 mmol) of D1 and 1.8 g (13 mmol) of potassium carbonate, 800 ml of THF and 400 ml of water are added. Subsequently, 67 mg (0.26 mmol) of triphenylphosphine and 59 mg (0.06 mmol) of tris(dibenzylideneacetone)dipalladium are added and the mixture is refluxed for 16 hours. Subsequently, water and toluene are added to the reaction mixture and the phases are separated. The aqueous phase is extracted twice with toluene and the combined organic phases are extracted once with water. The organic phase is filtered through aluminium oxide and then concentrated under reduced pressure. The product is obtained in solid form by chromatography (SiO2, heptane / THF 1 :20 > 1 : 10) and by repeated extraction by stirring from hot toluene.

[0221] Yield: 8.5 g (4.2 mmol), 66% of theory.

[0222] The following compounds can be prepared analogously:

[0223]

[0224]

[0225]

[0226]

[0227] Synthesis of intermediate Int-1

[0228]

[0229] 3 g (13.2 mmol) of CAS 68797-61-5, 10.4 g (13.2 mmol) of D4, 3.7 g (27 mmol) of potassium carbonate and 0.76 g (0.66 mmol) of tetrakis(triphenylphosphine)palladium(0) are mixed in 500 ml of toluene / ethanol / water (2:1 :1) and heated to reflux for 18 hours. After the conversion is complete, the reaction mixture is cooled to room temperature. The organic phase is expanded with toluene, washed twice with water and once with saturated aqueous sodium chloride solution. The organic phases are combined and concentrated on a rotary evaporator. The product is purified by column chromatography (SiO2; THF / heptane). Yield: 4.3 g (5.3 mmol; 40%).

[0230] Synthesis of intermediate Int-2

[0231]

[0232] Dissolve 15.0 g (100.7 mmol) of 4,6-dichloropyrimidine, 38.5 g (4-chloro-3- methoxyphenyl)boronic acid, 55.7 g (402.7 mmol) of potassium carbonate and 2.8 g (4.0 mmol) of bis(triphenylphosphine)Pd(II)chloride in 300 ml of acetonitrile / ethanol (2:1) and heat to reflux for 16 hours. After completion of the conversion, cool the reaction mixture to room temperature. Filter off the precipitated solid and wash with toluene and methanol. Concentrate the filtrate on a rotary evaporator. Purify the obtained solid by crystallization from dichloromethane / methanol. Yield: 20.9 g (57.9 mmol; 58%)

[0233] The following compounds can be prepared analogously from the corresponding boronic acid esters:

[0234]

[0235] Synthesis of intermediate Int-3

[0236]

[0237] Dissolve 16.0 g (44.3 mmol) of Int-2, 24.3 g (95.7 mmol) of bis(pinacolato)diboron and 17.4 g (177.2 mmol) of potassium acetate in 1000 ml of THF. After addition of 1.87 g (2.2 mmol) of Xphos Pd G3, heat the reaction mixture to reflux for 48 hours. Subsequently, cool the reaction mixture to room temperature and filter off the solid. Concentrate the filtrate on a rotary evaporator and purify by column chromatography (SiO2, heptane / ethyl acetate) and isolate the product. Yield: 12.4 g (22.7 mmol; 51%).

[0238] The following compounds can be prepared analogously from the corresponding boronic acid esters:

[0239]

[0240] Synthesis of emitter backbone segment 1

[0241]

[0242] A solution of 39.2 g (81 mmol) of EC1 (2202712-51-2), 54.0 g (170 mmol) of 2-bromo-4-chloro-1-iodobenzene, 44.8 g (324 mmol) of potassium carbonate and 570 mg (0.81 mmol) of bis(triphenylphosphine)palladium(II) chloride in 600 ml of toluene was stirred at 80°C. After 16 hours, 300 ml of water were added. The phases were separated, the aqueous phase was repeatedly extracted with toluene and the organic phases were repeatedly washed with water. The organic phases were combined and concentrated under reduced pressure. The residue obtained was repeatedly stirred with hot ethanol. The solid obtained was hot extracted on alumina with toluene. The precipitated solid was filtered. Yield: 35.1 g (57.5 mmol); 71% of theory.

[0243] The following compounds can be prepared analogously from the corresponding boronic esters:

[0244]

[0245]

[0246] Synthesis of the luminescent backbone segment 2

[0247]

[0248] A suspension of 34.6 g (57 mmol) of EC2, 78.8 g (118 mmol) of 1989597-72-9 and 24 g (226 mmol) of sodium carbonate in 1.2 1 of THF / water (2:1) was prepared. After the addition of 400 mg (0.57 mmol) of Pd(amphos)Cl2, the reaction mixture was refluxed for 16 hours. The solid that precipitated upon cooling to room temperature was filtered and purified by repeated hot extraction on alumina with dichloromethane as eluent and subsequent crystallization from dichloromethane / methanol. Yield: 52.3 g (34.4 mmol), 61% of theory.

[0249] The following compounds can be prepared analogously from the corresponding boronic esters:

[0250]

[0251]

[0252]

[0253] Synthesis of the luminescent core segment 2-Int

[0254]

[0255] EC3g was dissolved in 250 ml dichloromethane. After addition of 9 ml pyridine, the mixture was cooled to 0°C and 12 ml (73 mmol) trifluoromethanesulfonic anhydride was added dropwise so that the temperature did not exceed 2°C. The mixture was stirred for another hour at this temperature and then for 16 hours at room temperature. Subsequently, the reaction mixture was poured into 600 ml ice and stirred for 30 minutes. The mixture was transferred to a separation funnel and the organic phase was expanded with dichloromethane and washed three times with water. The combined aqueous phases were extracted twice with dichloromethane. The combined organic phases were filtered through silica gel and washed with ethyl acetate. After removal of the solvent on a rotary evaporator, the residue was repeatedly extracted by stirring with ethyl acetate at 60°C. After cooling to room temperature, the solid was filtered off to yield the product. Yield: 28.1 g (15.4 mmol; 85%).

[0256] The following compounds can be prepared analogously from the corresponding boronic esters:

[0257]

[0258] Synthesis of EC3i

[0259]

[0260] EC3g-Int, 6.4 g (34.1 mmol) 4-tert-butylphenylboronic acid, 4.7 g (34.1 mmol) potassium carbonate, 0.73 g (1.7 mmol) dppb and 0.39 g (0.43 mmol) tris(dibenzylideneacetone)dipalladium(0) were dissolved in 1000 ml dichloroethane / water (3:1) and stirred at 90°C for 16 hours. After completion of the conversion, the organic phase was expanded with ethyl acetate and the phases were separated. The aqueous phase was extracted twice with ethyl acetate and the combined organic phases were washed twice with water, dried over magnesium sulfate and filtered through silica gel. The desired product was obtained after purification by column chromatography (Si02; toluene / ethyl acetate). Yield: 6.1 g (3.4 mmol; 40%). The following compounds can be prepared analogously from the corresponding boronic esters:

[0261] The following compounds can be prepared analogously from the corresponding boronic esters:

[0262]

[0263]

[0264] Synthesis of emitter backbone segment 3

[0265]

[0266] The initial charge of 52.3 g (34.4 mmol) EC3, 35 g (71.5 mmol) tris(acetylacetonato)iridium(III) and 523 g hydroquinone was heated to 260°C and stirred at this temperature for 2 h. Subsequently, the reaction mixture was allowed to cool, 500 ml ethylene glycol was added dropwise at 220°C and 2 1 methanol was added dropwise starting at 120°C. After cooling to room temperature, the precipitated solid was filtered off through a double glass frit. The diastereomeric metal complex mixture containing the ΔΔ and ΛΛ isomers (racemic) and the ΛΔ isomer (meso) in a molar ratio of 1 :1 (from 1 HNMR) was dissolved in 300 ml dichloromethane, applied to 100 g of silica gel and separated by chromatography in the form of a toluene slurry with a silica gel column, with maximum light protection. The first fractions, hereinafter referred to as isomer 1 (11), were eluted first, followed by the later eluting isomer, hereinafter referred to as isomer 2 (12). And, after removal of the solvent, deep red solids were obtained. Yield: 11 : 29 g (15.2 mmol), 45% of theory; 12: 24.3 g (12.7 mmol), 37% of theory.

[0267] The metal complexes shown below can in principle be purified by chromatography (usually using an automatic column system (Torrent from Axel Semrau), recrystallization or hot extraction). The complex images cited below usually show only one isomer. Isomer mixtures can be separated but can also be used in OLEDs as isomer mixtures. However, there are also ligand systems in which only one pair of diastereomers is formed due to steric reasons.

[0268] The following compounds can be synthesized in a similar manner. Chromatographic separation of the usually obtained diastereomeric mixtures is carried out on flash silica gel in an automatic column system (Torrent from Axel Semrau):

[0269]

[0270]

[0271]

[0272]

[0273] Synthesis of the luminescent backbone structure segment 4

[0274]

[0275] An initial charge of 11.7 g (6.2 mmol) of EC4, 3.3 g (13 mmol) of bis(pinacolato)diboron, 2.4 g (25 mmol) of potassium acetate and 453 mg (0.61 mmol) of trans-dichlorobis(tricyclohexylphosphine)palladium(II) were dissolved in 600 ml of dioxane and refluxed for 16 hours. After cooling to room temperature, 400 ml of water were added, followed by repeated extraction with dichloromethane, the organic phases were combined and repeatedly extracted with water. The organic phases were then filtered through silica gel (dichloromethane) and concentrated under reduced pressure. The residue obtained was crystallized from dichloromethane / methanol. Yield: 12.8 g (6.1 mmol), 98% of theory.

[0276] The following compounds can be prepared analogously:

[0277]

[0278]

[0279]

[0280]

[0281] Synthesis of emitter Em1

[0282]

[0283] An initial charge of 2.7 g (1.3 mmol) of EC5, 5.3 g (2.6 mmol) of E1, 0.79 g (5.2 mmol) of cesium fluoride and 97 mg (0.13 mmol) of trans-dichlorobis(tricyclohexylphosphine)palladium(II) were dissolved in 80 ml of dioxane and refluxed for 16 hours. After cooling to room temperature, dichloromethane and water were added to the reaction mixture and the organic phase was removed. The aqueous phase was extracted twice with dichloromethane and the combined organic phases were extracted with water and then concentrated under reduced pressure. The residue was repeatedly purified by chromatography (SiO2, heptane / dichloromethane) and then crystallized once more from dichloromethane / methanol. The solid obtained was dried under reduced pressure at 200°C. Yield: 2.7 g (0.47 mmol), 36% of theory.

[0284] The following compounds can be prepared analogously:

[0285]

[0286]

[0287]

[0288] ​​

[0289]

[0290]

[0291]

[0292]

[0293]

[0294]

[0295]

[0296]

[0297] Physical instance

[0298] Manufacture of OLEDs and thin films for photophysical characterisation

[0299] The complexes of the present application can be processed from solution. There are many previous descriptions in the literature of the manufacture of OLEDs based entirely on solution, for example by spin coating as in WO 2004 / 037887. There are also many previous descriptions of the manufacture of OLEDs based on vacuum, including in WO 2004 / 058911. In the examples discussed below, layers applied in both solution-based and vacuum-based ways are combined within the OLED, so that processing up to and including the light-emitting layer is carried out from solution and subsequent layers (hole-blocking and electron-transporting layers) are carried out in vacuum. To this end, the general methods described previously are adapted to the case described here (layer thickness variations, materials) and combined as described below. The general structure is as follows: substrate / ITO (50 nm) / hole-injection layer (HIL) (60 nm) / hole-transporting layer (HTL) (20 nm) / light-emitting layer (EML) (60 nm) / hole-blocking layer (HBL) (10 nm) / electron-transporting layer (ETL) (40 nm) / cathode (aluminum, 100 nm). The substrates used were glass plates coated with structured ITO (indium tin oxide) having a thickness of 50 nm. For better processing, they were coated with PEDOT:PSS (poly(3,4-ethylenedioxy-2,5-thiophene) polystyrene sulfonate, available from Heraeus Precious Metals GmbH & Co. KG, Germany). The PEDOT:PSS was spun from water in air and subsequently baked at 180 °C in air for 10 minutes to remove residual water. The hole-transporting layer and the light-emitting layer were applied to these coated glass plates. The hole-transporting layer used was cross-linkable. The polymer used had the following structure, which can be synthesized according to WO 2013 / 156130:

[0300]

[0301] The hole-transporting polymer was dissolved in toluene. The typical solid content of this solution was about 5 g / l, at which time a layer thickness of 20 nm typical for a device as here was to be achieved by spin coating. The layer was spun in an inert gas atmosphere, in this case argon, and baked at 220 °C for 30 minutes.

[0302] The light-emitting layer always contains at least one matrix material (host material) and an emitting dopant (emitter). In addition, mixtures of various matrix materials and co-dopants can be used. Details given here in the form of TMM-A (92%): dopant (8%) mean that the material TMM-A is present in the light-emitting layer in a proportion of 92% by weight and the dopant is present in a proportion of 8% by weight. The mixture used for the light-emitting layer is dissolved in toluene or optionally chlorobenzene. The typical solid content of this solution is about 17 g / l, at which, as here, a layer thickness of 60 nm typical for the device is to be achieved by spin coating. The layer is spun in an inert gas atmosphere, in this case argon, and is baked at 160°C for 10 minutes. The materials used in this case are shown in Table 1.

[0303] Table 1 : EML materials used

[0304]

[0305]

[0306] The materials used for the hole-blocking layer and the electron-transporting layer are applied in a vacuum chamber by thermal vapour deposition. The electron-transporting layer can for example be composed of more than one material, which are added to one another by co-evaporation in a specific volume ratio. Details given here in the form of ETM1 : ETM2 (50% : 50%) mean that the materials ETM1 and ETM2 are each present in the layer in a proportion of 50% by volume. The materials used in this example are shown in Table 2. In the OLED assembly described here, ETM3 is used as HBL material and ETM1 : ETM2 (50:50) as ETL mixture.

[0307] Table 2: HBL and ETL materials used

[0308]

[0309] The cathode is formed by thermal evaporation of a 100 nm aluminium layer. The samples are encapsulated.

[0310] The films for photophysical characterisation are produced as single layers on quartz glass substrates by the method described above for the light-emitting layer. B1 is used here as host material and films of 30 nm thickness are produced. The samples are encapsulated.

[0311] Characterisation:

[0312] Measurement of emitter orientation in solution-processed films

[0313] In the measurement device, the film is treated with laser light irradiation of a solution containing the complex, the molecules are excited and then the photoluminescence spectrum of the emitted light is measured in an angle-dependent manner. The optical properties of the pure matrix material measured using the laws of optical physics can be used to calculate the result of the potential 100% level and 100% vertical orientation of the molecules. Subsequently, the measured values are fitted to the calculated extreme orientations, thus determining the orientation factor (optical orientation anisotropy). Perfect horizontal orientation of the molecules is described by Θ = 0, the isotropic case by Θ = 0.33, and the case of complete vertical alignment by Θ = 1. This value reflects the average orientation of all molecules in the layer that are excited by the photoluminescence process, which means that all complex molecules are located within the measurement spot irradiated by the laser light. It is not possible to determine the orientation of individual molecules with this method. Frischeisen et al., Applied Physics Letters 96, 073302 (2010) and Schmidt et al., Phys. Rev. Appl. 8, 037001 (2017) describe the performance of this optical measurement for determining the orientation of emitters.

[0314] Table 3 summarizes the optical orientation of the comparative materials and the selected materials of the present application. The complex of the present application is used in a slightly higher weight percentage to compensate for the higher molecular weight. It can be found that the two comparative complexes have an isotropic alignment in the film, while the complex of the present application has more horizontal alignment.

[0315] Table 3: Optical orientation anisotropy Θ

[0316]

[0317]

[0318] OLED components:

[0319] The OLEDs were characterized in a standard manner. For this, the electroluminescence spectrum and the current-voltage-luminance characteristics (IUL characteristics) were determined from the Lambertian emission characteristics and the external quantum efficiency at a specific luminance was calculated as a performance indicator.

[0320] All components examined emitted red light. The EML mixtures used and the resulting results are listed in Table 4. The complex of the present application is used in a slightly higher weight percentage to compensate for the higher molecular weight. It has been found that the complex of the present application with more horizontal alignment achieves a significant increase in quantum efficiency in the OLED components. More specifically, it was found in a direct comparison that the substituents of the present application lead to an increase in quantum efficiency for the same auxiliary ligand (D2 compared to Em4; D1 compared to Em1, Em13, Em12, Em7, Em14, Em9 and Em17).

[0321] Any of the complexes of the application cited above can be used similarly and lead to roughly comparable results.

[0322] Table 4: Results for solution-processed OLEDs (at 1000 cd / m 2 measured at a luminance of

[0323]

[0324] .

Claims

1. A compound having a structure selected from the group consisting of formulae (1a-1), (1a-2) and (1a-3): wherein the symbols and indices used are as follows: Y in formula (1a-2) is identical in each case and is R or X; X is the same in each occurrence and is a formula -(Ar) n a linear long chain aromatic group of R such that a film formed from the compound by solution processing has orientation; Ar is identical or different in each case and is a divalent radical selected from the group consisting of structures (Ar1), (Ar2), (Ar5) and (Ar6), Z in formula (1a-3) is -(Ar) n - R groups; wherein the dotted bond denotes the attachment of the unit, and V is CR2, O, S or NR; structure (Ar1) is selected from the group consisting of structures (Ar1a) to (Ar1d), n is the same or different at each occurrence and is an integer of 5 to 20, provided that in each -(Ar) n in the -R unit, at least 8 phenyl rings and optional cyclohexyl rings are connected to each other in a linear fashion via the para position; R can occur one or more times, on each occurrence identically or differently, and is: H, D, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched-chain alkyl group having 3 to 20 carbon atoms, or in each case can be substituted by one or more R 1 phenyl; R 1 in each case identical or different and are: H, D, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched-chain alkyl group having 3 to 20 carbon atoms.

2. The compound of claim 1, wherein - (Ar) n the R groups in the -R groups are identical or different in each case and are H, a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms.

3. The compound of claim 1, wherein and characterized in that structure (Ar2) is selected from the group consisting of structures (Ar2a), wherein the dotted bond indicates attachment of the structure, R and R 1 having the definition given in claim 1 ; wherein the dotted bond denotes the attachment of the structure, and V has the definition given in claim 1; and characterized in that structure (Ar5) is selected from the group consisting of structures (Ar5a) and (Ar5b), wherein the dotted bond denotes the attachment of the structure, and R has the definition given in claim 1. at least one Ar radical is identical or different in each case and is selected from the group consisting of structures (Ar1) and / or (Ar2).

4. The compound of claim 1, wherein n is an integer from 5 to 15, wherein the radicals (Ar1), (Ar2), (Ar5) and (Ar6) are selected such that a total of 8 to 24 phenyl rings and optionally cyclohexane rings are attached to each other in a linear manner via the para position.

5. The compound of claim 1, wherein the compound has a structure selected from the group consisting of formulae (2a-1), (2a-2) and (2a-3):

6. The compound of claim 1, wherein wherein the symbols used have the definitions listed in claim 1. all four phenylpyridine sub-ligands have the same substitution.

7. The compound of claim 1, wherein 9. A formulation comprising at least one compound according to any one of claims 1 to 7 and at least one further compound and / or at least one solvent.

8. A process for the preparation of a compound according to any one of claims 1 to 7, said process reacting a compound substituted with a reactive leaving group in place of X and optionally Y and / or Z with a compound A-(Ar) -R, wherein A is a reactive leaving group. n -R.

10. Use of a compound according to any one of claims 1 to 7 in an electronic device.

11. An electronic device comprising at least one compound according to any one of claims 1 to 7. the compound according to any one of claims 1 to 7 is used as a light-emitting compound in one or more light-emitting layers in combination with one or more matrix materials and / or in combination with one or more further triplet emitters.

12. Electronic device according to claim 11, which is an organic electroluminescent device, characterized in that 12. A compound according to any one of claims 1 to 7 for use in an electronic device.

Images