METAL COMPLEX

Description

[0001] The present invention relates to iridium complexes which are suitable for use in organic electroluminescence devices, in particular as emitters.

[0002] According to the state of the art, bis- and tris-orthometallated iridium complexes with aromatic ligands are primarily used as triplet emitters in phosphorescent organic electroluminescent devices (OLEDs). Examples of such complexes are tris(phenylpyridyl)iridium(III), as well as a variety of related complexes, for example, with 1- or 3-phenylisoquinoline ligands, with 2-phenylquinoline ligands, or with phenylcarbene ligands. Such complexes are also known with polypodal ligands, as described, for example, in US 7,332,232 and WO 2016 / 124304. WO2013 / 061850 and JP2013 168552 describe further iridium emitters for use in organic electroluminescent devices.

[0003] The object of the present invention is to provide new and, in particular, improved metal complexes which are suitable as emitters for use in OLEDs and which exhibit good lifetime and efficiency.

[0004] Surprisingly, it was found that the metal complexes described below, which contain a tetradentate tripodal ligand and a bidentate or two monodentate ligands, solve this problem and are very well suited for use in an organic electroluminescence device. These metal complexes and organic electroluminescence devices containing these complexes are therefore the subject of the present invention.

[0005] The subject of the invention is a compound of formula (1), the following applies to the symbols and indices used: L1< is a bidentate partial ligand coordinated to the iridium via one carbon atom and one nitrogen atom or via two carbon atoms; L2<, L3< are, in each occurrence, either the same or different, selected from an aryl or heteroaryl group with 5 to 14 aromatic ring atoms or a heteroalicyclic group with 5 to 7 ring atoms, each coordinated to the iridium via one carbon atom or one nitrogen atom, which is part of the aryl or heteroaryl group or the heteroalicyclic group respectively, and which may be substituted by one or more R groups; L4< is a bidentate ligand or, in each occurrence, either a monodentate ligand; ai is 1 if L4< is a bidentate ligand, and is 2 if L4< is a monodentate ligand; Vi is a group of formula (2) or (3), where the dashed bonds represent the position of the linkage of the subligands L1<, L2< and L3< and furthermore: A is the same or different at each occurrence CR2-CR2 or a group of the following formula (4): where the dashed bond represents the position of the bond of the subligands L1<, L2<, and L3< respectively, and * represents the position of the linkage of the unit of formula (4) with the central trivalent aryl or heteroaryl group in formula (2) or with the central cyclohexane group in formula (3); X1< is either CR or different from N in each occurrence; X2< is either CR or different from N in each occurrence; or two adjacent groups X2< together represent NR, O, or S, forming a five-membered ring, and the remaining groups X2< represent either CR or different from N in each occurrence; or two adjacent groups X2< together represent CR or N if one of the groups X3< represents N in the cycle, forming a five-membered ring, and the remaining groups X2< represent either CR or different from N in each occurrence; provided that a maximum of two adjacent groups X2< represent N in each ring;X 3< is C whenever it occurs in the same cycle, or one group X 3< stands for N and the other group X 3< in the same cycle stands for C; with the proviso that two adjacent groups X 2< together stand for CR or N if one of the groups X 3< stands for N in the cycle;Rist, in each occurrence the same or different H, D, F, Cl, Br, I, N(R 1< ) 2 , OR 1< , SR 1< , CN, NO 2 , COOH, C(=O)N(R 1< ) 2 , Si(R 1< ) 3 , Ge(R 1< ) 3 , B(OR 1< ) 2 , C(=O)R 1< , P(=O)(R 1< ) 2 , S(=O)R 1< , S(=O) 2 R 1< , OSO 2 R 1< , a straight-chain alkyl group with 1 to 20 C atoms or an alkenyl or alkynyl group with 2 to 20 C atoms or a branched or cyclic alkyl group with 3 to 20 C atoms, wherein the alkyl, an alkenyl or alkynyl group, each of which may be substituted with one or more R1< residues, and wherein one or more non-adjacent CH2 groups may be replaced by Si(R1<)2, C=O, NR1<, O, S or CONR1<, or an aromatic or heteroaromatic ring system with 5 to 40 aromatic ring atoms, each of which may be substituted by one or more R1< residues; two R residues may also form a ring system together;R1< is the same or different in each occurrence: H, D, F, Cl, Br, I, N(R2<)2, OR2<, SR2<, CN, NO2, Si(R2<)3, Ge(R2<)3, B(OR2<)2, C(=O)R2<, P(=O)(R2<)2, S(=O)R2<, S(=O)2R2<, OSO2R2<, a straight-chain alkyl group with 1 to 20 carbon atoms, or an alkenyl or alkynyl group with 2 to 20 carbon atoms, or a branched or cyclic alkyl group with 3 to 20 carbon atoms, wherein the alkyl, alkenyl, or alkynyl group is each linked to one or more R substituents. 2< can be substituted and wherein one or more non-adjacent CH 2 groups can be replaced by Si(R 2< ) 2 , C=O, NR 2< , O, S or CONR 2< , or an aromatic or heteroaromatic ring system with 5 to 40 aromatic ring atoms, each of which can be substituted by one or more R 2< residues; wherein two or more R 1< residues can form a ring system together;R 2< is, in each occurrence, the same or different H, D, F or an aliphatic, aromatic and / or heteroaromatic organic residue, in particular a hydrocarbon residue, with 1 to 20 C atoms, in which one or more H atoms may also be replaced by F. ;

[0006] This is therefore a complex with a tetradentate, tripodal ligand, which has one bidentate and two monodentate subligands, and with one bidentate or two monodentate ligands. "Bidentate subligand" means that the subligand in the complex coordinates to or binds to iridium via two coordination sites, and "monodentate subligand" means that the subligand in the complex coordinates to or binds to iridium via one coordination site. Tripodal means that the ligand has three subligands that are bound to bridge V or the bridge of formula (2) or (3). Since the ligand containing bridge V has one bidentate and two monodentate subligands, the result is a tetradentate ligand overall, i.e., a ligand that coordinates to or binds to iridium via four coordination sites. The term "bidentate subligand" or "monodentate subligand"In the context of this application, "monodentate partial ligand" means that L1< would be a bidentate ligand, and L2< and L3< would be monodentate ligands, if bridge V or the bridge of formula (2) or (3) were not present. However, due to the formal abstraction of a hydrogen atom from these bidentate or monodentate ligands and their attachment to bridge V or the bridge of formula (2) or (3), they are no longer separate ligands, but rather part of the resulting tetradentate ligand, hence the term "partial ligand" is used.

[0007] The bonds between the ligands or sub-ligands and the iridium can be coordination bonds or covalent bonds, and the covalent component of the bond can vary depending on the ligand. When the present application refers to the ligand or sub-ligand as coordinating or binding to the iridium, this means, within the meaning of the present application, any type of bond between the ligands or sub-ligands and the iridium, regardless of the covalent component of the bond.

[0008] When two residues R and R< ≡ 1 form a ring system, this system can be monocyclic or polycyclic, aliphatic, heteroaliphatic, aromatic, or heteroaromatic. These residues forming the ring system can be adjacent, i.e., bonded to the same carbon atom or to carbon atoms directly bonded to one another, or they can be further apart. Such ring formation is preferred when the residues are bonded to the same carbon atom or to carbon atoms directly bonded to one another.

[0009] In the context of this description, the phrase "two or more residues can form an aliphatic ring" means, among other things, that the two residues are linked to each other by a chemical bond involving the formal elimination of two hydrogen atoms. This is illustrated by the following scheme:

[0010] The formation of a condensed aromatic or heteroaromatic group is also possible, as illustrated by the following scheme:

[0011] Furthermore, the above formulation should also be understood to mean that if one of the two residues represents hydrogen, the second residue binds to the position to which the hydrogen atom was bonded, forming a ring. This is illustrated by the following diagram:

[0012] A heteroalicyclic group according to the present invention is an aliphatic cyclic group comprising at least one heteroatom as part of the cycle. Preferably, it comprises one or two heteroatoms as part of the cycle, wherein the heteroatoms are preferably selected from the group consisting of nitrogen, oxygen, and sulfur.

[0013] An aryl group according to this invention contains 6 to 40 carbon atoms; a heteroaryl group according to this invention contains 2 to 40 carbon atoms and at least one heteroatom, provided that the sum of carbon atoms and heteroatoms is at least 5. The heteroatoms are preferably selected from nitrogen, oxygen, and / or sulfur. The heteroaryl group preferably contains a maximum of three heteroatoms. An aryl group or heteroaryl group is understood to be either a simple aromatic cycle, i.e., benzene, or a simple heteroaromatic cycle, for example, pyridine, pyrimidine, thiophene, etc., or a fused aryl or heteroaryl group, for example, naphthalene, anthracene, phenanthrene, quinoline, isoquinoline, etc.

[0014] An aromatic ring system according to this invention contains 6 to 40 carbon atoms in the ring system. A heteroaromatic ring system according to this invention contains 1 to 40 carbon atoms and at least one heteroatom in the ring system, provided that the sum of carbon atoms and heteroatoms is at least 5. The heteroatoms are preferably selected from nitrogen, oxygen, and / or sulfur. An aromatic or heteroaromatic ring system according to this invention is understood to be a system that does not necessarily contain only aryl or heteroaryl groups, but in which several aryl or heteroaryl groups may also be interrupted by a non-aromatic unit (preferably less than 10% of the atoms other than hydrogen), such as a carbon, nitrogen, or oxygen atom, or a carbonyl group. For example, systems such as 9,9'-spirobifluorene, 9,9-diarylfluorene, triarylamine, diaryl ether, stilbene, etc., are also considered to be of this kind.Aromatic ring systems as defined in this invention include systems in which two or more aryl groups are interrupted, for example, by a linear or cyclic alkyl group or by a silyl group. Furthermore, systems in which two or more aryl or heteroaryl groups are directly bonded to one another, such as biphenyl, terphenyl, quaterphenyl, or bipyridine, are also to be understood as aromatic or heteroaromatic ring systems. Preferred aromatic or heteroaromatic ring systems are simple aryl or heteroaryl groups, as well as groups in which two or more aryl or heteroaryl groups are directly linked to one another, for example, biphenyl or bipyridine, and fluorene or spirobifluorene.

[0015] Within the scope of the present invention, the term alkyl group is used as a generic term for both linear or branched alkyl groups and cyclic alkyl groups. Similarly, the terms alkenyl group and alkynyl group are used as generic terms for both linear or branched alkenyl and alkynyl groups, respectively, and for cyclic alkenyl and alkynyl groups, respectively. A cyclic alkyl, alkoxy, or thioalkoxy group within the meaning of this invention is understood to be a monocyclic, a bicyclic, or a polycyclic group, respectively.

[0016] Within the scope of the present invention, the following groups, for example, are formed under a C1 to C20 alkyl group, in which individual hydrogen atoms or CH2 groups may also be substituted by the groups mentioned above: methyl, ethyl, n-propyl, i-propyl, cyclopropyl, n-butyl, i-butyl, s-butyl, t-butyl, cyclobutyl, 2-methylbutyl, n-pentyl, s-pentyl, t-pentyl, 2-pentyl, neo-pentyl, cyclopentyl, n-hexyl, s-hexyl, t-hexyl, 2-hexyl, 3-hexyl, neo-hexyl, 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-Diethyln-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- understood. Examples of alkenyl groups include ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, and cyclooctadienyl. Examples of alkynyl groups include ethinyl, propynyl, butynyl, pentinyl, hexinyl, heptinyl, and octynyl. Examples of groups with an OR of 1< include methoxy, trifluoromethoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, and 2-methylbutoxy.

[0017] An aromatic or heteroaromatic ring system with 5–40 aromatic ring atoms, which may be further substituted with the aforementioned substituents and which may be linked via any positions on the aromatic or heteroaromatic compound, includes, for example, groups derived from benzene, naphthalene, anthracene, benzanthracene, phenanthrene, benzophenanthrene, pyrene, chrysene, perylene, fluoranthene, benzfluoranthene, naphthacene, pentacene, benzopyrene, biphenyl, biphenylene, terphenyl, terphenylene, fluorene, spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- or trans-indenofluorene, cis- or trans-monobenzoindenofluorene, cis- or trans-dibenzoindenofluorene, truxene, isotruxene, spirotruxene, spiroisotruxene, furan, benzofuran, isobenzofuran, etc. Dibenzofuran, thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, indolocarbazole, indenocarbazole, pyridine, quinoline, isoquinoline, acridine, phenanthridine,Benzo-5,6-chinolin, Benzo-6,7-chinolin, Benzo-7,8-chinolin, Phenothiazin, Phenoxazin, Pyrazol, Indazol, Imidazol, Benzimidazol, Naphthimidazol, Phenanthrimidazol, Pyridimidazol, Pyrazinimidazol, Chinoxalinimidazol, Oxazol, Benzoxazol, Naphthoxazol, Anthroxazol, Phenanthroxazol, Isoxazol, 1,2-Thiazol, 1,3-Thiazol, Benzothiazol, Pyridazin, Benzopyridazin, Pyrimidin, Benzpyrimidin, Chinoxalin, 1,5-Diazaanthracen, 2,7-Diazapyren, 2,3-Diazapyren, 1,6-Diazapyren, 1,8-Diazapyren, 4,5-Diazapyren, 4,5,9,10-Tetraazaperylen, Pyrazin, Phenazin, Phenoxazin, Phenothiazin, Fluorubin, Naphthyridin, Azacarbazol, Benzocarbolin, Phenanthrolin, 1,2,3-Triazol, 1,2,4-Triazol, Benzotriazol, 1,2,3-Oxadiazol, 1,2,4-Oxadiazol, 1,2,5-Oxadiazol, 1,3,4-Oxadiazol, 1,2,3-Thiadiazol, 1,2,4-Thiadiazol, 1,2,5-Thiadiazol, 1,3,4-Thiadiazol, 1,3,5-Triazin, 1,2,4-Triazin, 1,2,3-Triazin, Tetrazol, 1,2,4,5-Tetrazin, 1,2,3,4-Tetrazin, 1,2,3,5-Tetrazin, Purin, Pteridin, Indolizin und Benzothiadiazol.,

[0018] In a preferred embodiment, the compound according to the invention is electrically neutral. The iridium is present as Ir(III). Charge neutrality is achieved by the charges of the partial ligands and ligands L1< to L4< balancing the charge of the triply positively charged iridium. L1< can be neutral, monoanionic, or dianionic. L2< and L3< can each be neutral or monoanionic. Examples of suitable combinations of the partial ligands and ligands L1< to L4< are listed in the following table: L 1< L 2< L 3< L 4< (bidentat) L 4< (monodentat) monoanionic monoanionic monoanionic neutral --- monoanionic monoanionic neutral monoanionic --- monoanionic neutral neutral Dianionian --- monoanionic monoanionic monoanionic --- 2x neutral monoanionic monoanionic neutral --- neutral + monoanionic monoanionic neutral neutral --- 2x monoanionic neutral monoanionic monoanionic monoanionic --- neutral monoanionic neutral Dianionian --- neutral monoanionic monoanionic --- neutral + monoanionic neutral monoanionic neutral --- 2x monoanionic Dianionian monoanionic neutral neutral --- Dianionian neutral neutral monoanionic --- Dianionian monoanionic neutral --- 2x neutral Dianionian neutral neutral --- neutral + monoanionic

[0019] In a preferred embodiment of the invention, L 1< is monoanionic, so that the first six entries in the table are preferred.

[0020] Preferred embodiments of the bridgehead V, i.e. the structure of formula (2) or (3), are described below.

[0021] In a preferred embodiment of the invention, all groups X 1< in the group of formula (2) represent CR, such that the central trivalent cycle of formula (2) represents a benzene, or all groups X 1< represent a nitrogen atom, such that the central trivalent cycle of formula (2) represents a triazine. Particularly preferably, all groups X 1< represent CR, whether the same or different.

[0022] For preferred residues R on the trivalent central benzene ring of formula (2) or on the central cyclohexane ring of formula (3), the following applies: Rist, in each occurrence the same or different H, D, F, CN, OR 1< , a straight-chain alkyl group with 1 to 10 C atoms, preferably with 1 to 4 C atoms, or an alkenyl group with 2 to 10 C atoms, or a branched or cyclic alkyl group with 3 to 10 C atoms, preferably with 3 to 6 C atoms, each of which may be substituted with one or more R 1< groups, but preferably is unsubstituted, or an aromatic or heteroaromatic ring system with 5 to 24 aromatic ring atoms, preferably with 6 to 12 aromatic ring atoms, each of which may be substituted by one or more R 1< groups; the R group may also form a ring system with an R group at X 2< ;R 1< is the same or different in each occurrence H, D, F, CN, OR 2< , a straight-chain alkyl group with 1 to 10 C atoms, preferably with 1 to 4 C atoms, or an alkenyl group with 2 to 10 C atoms or a branched or cyclic alkyl group with 3 to 10 C atoms, preferably with 3 to 6 C atoms, each of which may be substituted with one or more R 2< groups, but preferably is unsubstituted, or an aromatic or heteroaromatic ring system with 5 to 24 aromatic ring atoms, preferably with 6 to 12 aromatic ring atoms, each of which may be substituted by one or more R 2< groups; in this respect, two or more adjacent R 1< groups may form a ring system together;R 2< is, in each occurrence, the same or different H, D, F or an aliphatic, aromatic and / or heteroaromatic organic residue with 1 to 20 C atoms, in which one or more H atoms may also be replaced by F, preferably an aliphatic or aromatic hydrocarbon residue with 1 to 12 C atoms.

[0023] Particularly preferably, all groups X 1< in formula (2) represent CH or CD, especially CH. Furthermore, all groups R in the group of formula (3) preferably represent H or D, especially H, such that the central cycle in formula (3) represents an unsubstituted cyclohexane group.

[0024] Preferred embodiments of the group of formulas (2) and (3) are the structures of the following formulas (2a) and (3a), respectively. the symbols used have the meanings mentioned above.

[0025] In the following, preferred bivalent arylene or heteroarylene units A or the groups of formula (4) are described as they occur in the group of formulas (2) and (3).

[0026] In a preferred embodiment of the invention, the symbol X 3< in the group of formula (4) represents C, so that the group of formula (4) is represented by the following formula (4'): the symbols have the meanings listed above.

[0027] The group of formula (4) or (4') can represent a heteroaromatic five-membered ring or an aromatic or heteroaromatic six-membered ring. In a preferred embodiment of the invention, the group of formula (4) or (4') contains a maximum of two heteroatoms in the aryl or heteroaryl group, respectively, and more preferably a maximum of one heteroatom. This does not preclude the possibility that substituents, which may be bonded to this group, may also contain heteroatoms. Furthermore, this definition does not preclude the formation of aromatic or heteroaromatic structures through ring formation of substituents, such as naphthalene, benzimidazole, etc. Examples of suitable groups of formula (4) or (4') are benzene, pyridine, pyrimidine, pyrazine, pyridazine, pyrrole, furan, thiophene, pyrazole, imidazole, oxazole, and thiazole.

[0028] Preferred embodiments of the group of formula (4') are the structures of the following formulas (4a) to (4q), the symbols used have the meanings mentioned above.

[0029] If one group X 3< in formula (4) represents a carbon atom and the other group X 3< represents a nitrogen atom, preferred embodiments of the group of formula (4) are the structures of the following formulas (4r) to (4y), the symbols used have the meanings mentioned above.

[0030] Ortho-phenylene, i.e. a group of the above-mentioned formula (4a), is particularly favored.

[0031] If two or three groups of formula (4) are present, they may be identical or different. In a preferred embodiment of the invention, if two or three groups of formula (4) are present, these groups are identical and are also identically substituted.

[0032] The following combinations are preferred for Group A: all three groups A represent the same group of formula (4), in particular the same group of formula (4a); two groups A represent the same group of formula (4), in particular the same group of formula (4a), and the third group A represents CR 2 -CR 2; one group A represents a group of formula (4), in particular the same group of formula (4a), and the other two groups A represent the same group CR 2 -CR 2; or all three groups A represent the same group CR 2 -CR 2.

[0033] In this context, "the same group of formula (4)" or "the same group of formula (4a)" means that these groups have the same basic structure and are substituted in the same way. Furthermore, "the same group CR 2 -CR 2" means that these groups are substituted in the same way.

[0034] Preferred R groups on the -CR 2 -CR 2 - are selected from the group consisting of H, D, F and an alkyl group with 1 to 5 C atoms, wherein H atoms may also be replaced by D or F and wherein adjacent R groups may form a ring system with each other. Particularly preferred R groups on these groups are selected from H, D, CH 3 or CD 3, or two R groups bonding to the same carbon atom form a cyclopentane or cyclohexane ring together with the carbon atom to which they bond. Very preferred R groups on this group are selected from H or D, especially H.

[0035] Therefore, the following combinations are particularly preferred for groups A: all three groups A represent the group of formula (4a) with R = H; two groups A represent the group of formula (4a) with R = H, and the third group A represents CH 2 -CH 2 ; one group A represents a group of formula (4a) with R = H and the other two groups A represent the group CH 2 -CH 2 ; or all three groups A represent the group CH 2 -CH 2 .

[0036] The structures of formulas (2) and (3) are particularly preferred, selected from the structures of the following formulas (2a) to (2d) and (3a) to (3d). The symbols used have the meanings mentioned above. In the central benzene ring of formulas (2a) to (2d), R preferably represents H or D, particularly H. Formulas (2a) and (2c) are particularly preferred.

[0037] Particularly preferred are the substituents R in formulas (2a) to (2d) and (3a) to (3d), whether H, D, or an alkyl group with 1 to 4 carbon atoms, regardless of their occurrence. R = H or D, especially H, is particularly preferred. Therefore, particularly preferred embodiments of formulas (2a) to (2d) and (3a) to (3d) are the structures of the following formulas (2a-1) to (2d-1) and (3a-1) to (3d-1). the symbols used have the meanings mentioned above.

[0038] The bidentate partial ligand L1< is described below. As described above, L1< coordinates to the iridium via a carbon atom and a nitrogen atom or via two carbon atoms. In a preferred embodiment, the partial ligand L1< coordinates to the iridium via a carbon atom and a nitrogen atom.

[0039] It is still preferred if the metallacycle formed from the iridium and the partial ligand L1< is a five-membered ring. The formation of a five-membered ring is shown schematically below: where N represents a coordinating nitrogen atom and C a coordinating carbon atom, and the carbon atoms shown represent atoms of the sub-ligand L 1<.

[0040] In a preferred embodiment of the invention, the partial ligand L 1< represents a structure according to one of the following formulas (L 1< -1) or (L 1< -2), where the dashed bond represents the bond of the subligand L 1< to V or to the bridge of formula (2) or (3), and the following applies to the other symbols used: CyC is, in each occurrence, a substituted or unsubstituted aryl or heteroaryl group with 5 to 14 aromatic ring atoms, each coordinated to the iridium via a carbon atom and covalently bonded to CyD; CyD is, in each occurrence, a substituted or unsubstituted heteroaryl group with 5 to 14 aromatic ring atoms or a substituted or unsubstituted heteroalicyclic group with 5 to 7 ring atoms, each coordinated to the iridium via a nitrogen atom or a carbene carbon atom and covalently bonded to CyC; Several of the optional substituents can form a ring system together; the optional residues are preferably selected from the residues R mentioned above.

[0041] CyD coordinates via a neutral or anionic nitrogen atom or via a carbene carbon atom, preferably via a neutral nitrogen atom or via a carbene carbon atom. Furthermore, CyC coordinates via an anionic carbon atom.

[0042] If several of the substituents, especially several R groups, form a ring system together, the formation of a ring system from substituents bonded to directly adjacent carbon atoms is possible. Furthermore, it is also possible for the substituents on CyC and CyD to form a ring together, whereby CyC and CyD can also together form a single fused aryl or heteroaryl group as a bidentate partial ligand.

[0043] In a preferred embodiment of the present invention, CyC is an aryl or heteroaryl group with 6 to 13 aromatic ring atoms, particularly preferably with 6 to 10 aromatic ring atoms, most preferably with 6 aromatic ring atoms, which is coordinated to the iridium via a carbon atom, which may be substituted with one or more R groups and which is connected to CyD via a covalent bond.

[0044] Preferred embodiments of the CyC group are the structures of the following formulas (CyC-1) to (CyC-20), wherein the CyC group binds to CyD at the position marked by # and coordinates to the iridium at the position marked by *. where R has the meanings mentioned above and the following applies to the other symbols used: X is the same or different CR or N for each occurrence, with the proviso that a maximum of two symbols X per cycle represent N; Wist is the same or different NR, O or S for each occurrence; with the proviso that if bridge V or bridge of formula (2) or (3) is bonded to CyC, a symbol X represents C and bridge of formula (2) or (3) is bonded to this carbon atom. If the CyC group is bonded to bridge V or bridge of formula (2) or (3), the bond preferably occurs via the position marked "o" in the formulas shown above, so that the symbol X marked "o" then preferably represents C. The structures shown above that do not contain a symbol X marked "o" are preferably not directly bonded to bridge V or bridge of formula (2) or (3), since such a bond to the bridge is not advantageous for steric reasons.

[0045] Preferably, at most one symbol X in CyC represents N and particularly preferably all symbols X represent CR, with the proviso that if the bridge V or the bridge of formula (2) or (3) is bonded to CyC, one symbol X represents C and the bridge V or the bridge of formula (2) or (3) is bonded to this carbon atom.

[0046] Particularly favored groups CyC are the groups of the following formulas (CyC-1a) to (CyC-20a), The symbols used have the meanings mentioned above, and when bridge V or bridge of formula (2) or (3) is bonded to CyC, a residue R is not present, and bridge V or bridge of formula (2) or (3) is bonded to the corresponding carbon atom. When the CyC group is bonded to bridge V or bridge of formula (2) or (3), the bond preferably occurs via the position marked "o" in the formulas shown above, so that residue R is not present in this position. The structures shown above that do not contain a carbon atom marked "o" are preferably not directly bonded to bridge V or bridge of formula (2) or (3). Preferably, there are a maximum of three substituents R other than H or D, more preferably a maximum of two substituents R, and most preferably a maximum of one substituent.

[0047] Preferred groups among groups (CyC-1) to (CyC-20) are groups (CyC-1), (CyC-3), (CyC-8), (CyC-10), (CyC-12), (CyC-13) and (CyC-16), and especially preferred are groups (CyC-1a), (CyC-3a), (CyC-8a), (CyC-10a), (CyC-12a), (CyC-13a) and (CyC-16a).

[0048] In a further preferred embodiment of the invention, CyD is a heteroaryl group with 5 to 13 aromatic ring atoms, particularly preferably with 6 to 10 aromatic ring atoms, or a heteroalicyclic group with 5 or 6 ring atoms, preferably with 5 ring atoms, each of which is coordinated to the iridium via a neutral or anionic nitrogen atom or via a carbene carbon atom and which may be substituted with one or more R groups and which is connected to CyC via a covalent bond.

[0049] Preferred embodiments of the CyD group are the structures of the following formulas (CyD-1) to (CyD-23), wherein the CyD group binds to CyC at the position marked by # and coordinates to the iridium at the position marked by *. where X and R have the meanings mentioned above and W stands for CR 2 , NR, O or S, with the proviso that if bridge V or the bridge of formula (2) or (3) is bonded to CyD, then symbol X represents C and bridge V or the bridge of formula (2) or (3) is bonded to this carbon atom; or if bridge V or the bridge of formula (2) or (3) is bonded to CyD, then in formulas (CyD-7) and (CyD-8) a group R is not present and bridge V is bonded in this position. If group CyD is bonded to bridge V or the bridge of formula (2) or (3), the bonding preferably occurs via the position marked "o" in the formulas shown above, so that then the symbol X marked "o" preferably represents C. The structures shown above, which do not contain a symbol X marked with "o", are preferably not directly connected to bridge V or the bridge of formula (2).(3) bound, since such a bond to the bridge is not advantageous for steric reasons.

[0050] In this process, groups (CyD-1) to (CyD-4) and (CyD-9) to (CyD-20) coordinate to the iridium via a neutral nitrogen atom, (CyD-5) to (CyD-8) via a carbene carbon atom and (CyD-21) to (CyD-23) via an anionic nitrogen atom.

[0051] Preferably, at most one symbol X in CyD represents N, and particularly preferably all symbols X represent CR, with the proviso that if the bridge V or the bridge of formula (2) or (3) is bonded to CyD, one symbol X represents C and the bridge V or the bridge of formula (2) or (3) is bonded to this carbon atom.

[0052] Particularly favored groups CyD are the groups of the following formulas (CyD-1a) to (CyD-23a), The symbols used have the meanings mentioned above, and when bridge V or bridge of formula (2) or (3) is bonded to CyD, a residue R is not present, and bridge V or bridge of formula (2) or (3) is bonded to the corresponding carbon atom. When the group CyD is bonded to bridge V or bridge of formula (2) or (3), the bond preferably occurs via the position marked "o" in the formulas shown above, so that residue R is not present in this position. The structures shown above that do not contain a carbon atom marked "o" are preferably not directly bonded to bridge V or bridge of formula (2) or (3). Preferably, there are a maximum of three substituents R other than H or D, more preferably a maximum of two substituents R, and most preferably a maximum of one substituent.

[0053] Preferred groups among groups (CyD-1) to (CyD-12) are groups (CyD-1), (CyD-2), (CyD-3), (CyD-4), (CyD-5) and (CyD-6), in particular (CyD-1), (CyD-2) and (CyD-3), and especially preferred are groups (CyD-1a), (CyD-2a), (CyD-3a), (CyD-4a), (CyD-5a) and (CyD-6a), in particular (CyD-1a), (CyD-2a) and (CyD-3a).

[0054] In a preferred embodiment of the invention, CyC is an aryl or heteroaryl group with 6 to 13 aromatic ring atoms, and CyD is simultaneously a heteroaryl group with 5 to 13 aromatic ring atoms. Particularly preferred is CyC an aryl or heteroaryl group with 6 to 10 aromatic ring atoms, and CyD a heteroaryl group with 5 to 10 aromatic ring atoms. Most particularly preferred is CyC an aryl or heteroaryl group with 6 aromatic ring atoms and CyD a heteroaryl group with 6 to 10 aromatic ring atoms. CyC and CyD can be substituted with one or more R groups.

[0055] The above-mentioned preferred groups (CyC-1) to (CyC-20) and (CyD-1) to (CyD-21) can be combined arbitrarily, provided that at least one of the groups CyC or CyD has a suitable connection point to the bridge V or a bridge of formula (2) or (3), respectively, where suitable connection points in the above-mentioned formulas are marked with "o".

[0056] It is particularly preferred if the groups CyC and CyD mentioned above as particularly preferred, i.e., the groups of formulas (CyC-1a) to (CyC-20a) and the groups of formulas (CyD1-a) to (CyD-21a), are combined with one another, provided that at least one of the preferred groups CyC or CyD has a suitable connection point to bridge V or the bridge of formula (2) or (3), respectively, where suitable connection points in the formulas mentioned above are marked with "o". Combinations in which neither CyC nor CyD has such a suitable connection point for bridge V or the bridge of formula (2) or (3) are therefore not preferred.

[0057] It is particularly preferred if one of the groups (CyC-1), (CyC-3), (CyC-8), (CyC-10), (CyC-12), (CyC-13) and (CyC-16), and especially the groups (CyC-1a), (CyC-3a), (CyC-8a), (CyC-10a), (CyC-12a), (CyC-13a) and (CyC-16a), is combined with one of the groups (CyD-1), (CyD-2) and (CyD-3), and especially with one of the groups (CyD-1a), (CyD-2a) and (CyD-3a).

[0058] Preferred subligands (L 1< -1) are the structures of formulas (L 1< -1-1) to (L 1< -1-3), and preferred subligands (L 1< -2) are the structures of formulas (L 1< -2-1) to (L 1< -2-5) that coordinate to the iridium via the two positions marked with *. where the symbols used have the meanings mentioned above and "o" represents the position of the bond to bridge V or the bridge of formula (2) or (3).

[0059] Particularly preferred subligands (L 1< -1) are the structures of formulas (L 1< -1-1a) to (L 1< -1-3b), and particularly preferred subligands (L 1< -2) are the structures of formulas (L 1< -2-1a) to (L 1< -2-5a) that coordinate to the iridium via the two positions marked with *. where the symbols used have the meanings mentioned above and "o" represents the position of the bond to bridge V or the bridge of formula (2) or (3), respectively. Preferably, there are a maximum of three substituents R other than H or D, more preferably a maximum of two substituents R, and most preferably a maximum of one substituent.

[0060] When two R groups, one bonded to CyC and the other to CyD, form an aromatic ring system, bridged partial ligands and partial ligands that together constitute a single larger heteroaryl group can result. Ring formation between the substituents on CyC and CyD is preferentially mediated by a group according to one of the following formulas (5) to (14). where R 1< has the meanings mentioned above and the dashed bonds indicate the bonds to CyC and CyD. The unsymmetrical groups mentioned above can be incorporated in either of the two possibilities. For example, in the group of formula (14), the oxygen atom can bond to the CyC group and the carbonyl group to the CyD group, or the oxygen atom can bond to the CyD group and the carbonyl group to the CyC group.

[0061] The group of formula (11) is particularly preferred if it results in the formation of a six-membered ring, as illustrated below by formulas (L 1< -21) and (L 1< -22).

[0062] Preferred ligands formed by ring formation of two residues R on CyC and CyD are the structures listed below with formulas (L 1< -3) to (L 1< -30), where the symbols used have the meanings mentioned above and "o" indicates the position at which this sub-ligand is linked to bridge V or the bridge of formula (2) or (3).

[0063] In a preferred embodiment of the partial ligands of formulas (L 1< -3) to (L 1< -30) all symbols X stand for CR, or one symbol X stands for N and the other symbols X stand for CR.

[0064] In a further embodiment of the invention, it is preferred that, in groups (CyC-1) to (CyC-20) or (CyD-1) to (CyD-21) or in the partial ligands (L 1< -3) to (L 1< -30), if one of the atoms X represents N, a group R, which is not hydrogen or deuterium, is bonded as a substituent adjacent to this nitrogen atom. This applies analogously to the preferred structures (CyC-1a) to (CyC-20a) or (CyD-1a) to (CyD-14b), in which a group R, which is not hydrogen or deuterium, is preferably bonded as a substituent adjacent to a non-coordinating nitrogen atom.This substituent R is preferably a group selected from CF3, OCF3, alkyl groups with 1 to 10 carbon atoms, in particular branched or cyclic alkyl groups with 3 to 10 carbon atoms, OR1<, where R1< represents an alkyl group with 1 to 10 carbon atoms, in particular a branched or cyclic alkyl group with 3 to 10 carbon atoms, a dialkylamino group with 2 to 10 carbon atoms, aromatic or heteroaromatic ring systems, or aralkyl or heteroaralkyl groups. These groups are sterically demanding. Furthermore, this substituent R can preferably also form a cycle with a neighboring substituent R.

[0065] Another suitable bidentate subligand L 1< is a structure according to one of the following formulas (L 1< -31) and (L 1< -32), where R has the meanings mentioned above, * represents the position of coordination to the metal, "o" represents the position of the linkage of the partial ligand with the bridge V or the bridge of formula (2) or (3), and furthermore: X is the same or different CR or N at each occurrence, with the proviso that at most one symbol X per cycle stands for N.

[0066] If two residues R, which are bonded to adjacent carbon atoms in the partial ligands (L 1< -31) and (L 1< -32) respectively, form an aromatic cycle together, this cycle together with the two adjacent carbon atoms is preferably a structure of formula (15), where the dashed bonds symbolize the linkage of this group in the subligand and Y, whether the same or different, represents CR 1< or N at each occurrence, and preferably at most one symbol Y represents N.

[0067] In a preferred embodiment of the partial ligand (L1<-31) or (L1<-32), a maximum of one group of formula (15) is present. These are therefore preferably partial ligands of the following formulas (L1<-33) to (L1<-38). where X has the meanings mentioned above, but the residues R, when X stands for CR, do not form an aromatic or heteroaromatic ring system together, and the other symbols have the meanings mentioned above.

[0068] In a preferred embodiment of the invention, in the partial ligand of the formula (L 1< -31) to (L 1< -38) a total of 0, 1 or 2 of the symbols X and, if present, Y represent N. Particularly preferred is a total of 0 or 1 of the symbols X and, if present, Y represent N.

[0069] Preferred embodiments of formulas (L 1< -33) to (L 1< -38) are the structures of the following formulas (L 1< -33a) to (L 1< -38f), where the symbols used have the meanings mentioned above and "o" indicates the position of the linkage with bridge V or the bridge of formula (2) or (3), respectively. Preferably, there are a maximum of three substituents R other than H or D, more preferably a maximum of two substituents R, and most preferably a maximum of one substituent.

[0070] In a preferred embodiment of the invention, group X, which is in the ortho position for coordination to the metal, represents CR. In this group, residue R, which is also bound in the ortho position for coordination to the metal, is preferably selected from the group consisting of H, D, F, and methyl.

[0071] In a further embodiment of the invention, it is preferred that, if one of the atoms X or, if present, Y represents N, a substituent group R is bonded adjacent to this nitrogen atom, which is not hydrogen or deuterium. This substituent R is preferably a group selected from CF3, OCF3, alkyl groups with 1 to 10 carbon atoms, in particular branched or cyclic alkyl groups with 3 to 10 carbon atoms, OR1<, where R1< represents an alkyl group with 1 to 10 carbon atoms, in particular a branched or cyclic alkyl group with 3 to 10 carbon atoms, a dialkylamino group with 2 to 10 carbon atoms, aromatic or heteroaromatic ring systems, or aralkyl or heteroaralkyl groups. These groups are sterically demanding. Furthermore, this substituent R can preferably also form a cycle with an adjacent substituent R.

[0072] In a preferred embodiment of the invention, L 1< is a partial ligand according to one of the following formulas (L 1< -39) and (L 1< -40), which is coordinated to the iridium via the two positions marked with *, where "o" denotes the position of the connection with bridge V and the following also applies: Xist is the same or different CR or N in each occurrence; Zist is CR', CR or N, with the proviso that exactly one Z stands for CR' and the other Z stands for CR or N; where a maximum of one symbol X or Z per cycle represents N; R' is a group of the following formula (16) or (17), where the dashed bond indicates the linkage of the group to the partial ligand of formula (L 1< -39) or (L 1< -40); R" is the same or different in each occurrence: H, D, F, CN, a straight-chain alkyl group with 1 to 10 C atoms, in which one or more H atoms may also be replaced by D or F, or a branched or cyclic alkyl group with 3 to 10 C atoms, in which one or more H atoms may also be replaced by D or F, or an alkenyl group with 2 to 10 C atoms, in which one or more H atoms may also be replaced by D or F; in this case, two adjacent R" or R" substituents may also betwo R" residues on adjacent phenyl groups form a ring system together; or two R" residues on adjacent phenyl groups together represent a group selected from C(R 1< ) 2 , NR 1< , O or S, such that the two phenyl rings together with the bridging group represent a carbazole, fluorene, dibenzofuran or dibenzothiophene, and the further R" are defined as above; nist 0, 1, 2, 3, 4 or 5. .

[0073] The R 1< substituent on the nitrogen is defined as above and preferably represents an alkyl group with 1 to 10 C atoms or an aromatic or heteroaromatic ring system with 6 to 24 aromatic ring atoms, which may be substituted by one or more R 2< substituents, particularly preferably an aromatic or heteroaromatic ring system with 6 to 18 aromatic ring atoms, which may be substituted by one or more R 2< substituents, but is preferably unsubstituted.

[0074] In a preferred embodiment of the invention, n = 0, 1 or 2, preferably 0 or 1 and most preferably 0.

[0075] In a further preferred embodiment of the invention, both substituents R', which are bonded in the ortho positions to the carbon atom to which the group of formula (16) or (17) is bonded to the partial ligand L 1<, are the same or different from H or D.

[0076] In a preferred embodiment of the invention, X represents CR, either the same or different at each occurrence. More preferably, one group Z represents CR and the other group Z represents CR'. Particularly preferably, in the partial ligand (L1<-39) or (L1<-40), the groups X represent CR, either the same or different at each occurrence, and simultaneously, one group Z represents CR and the other group Z represents CR'. The partial ligand L1< preferably has a structure according to one of the following formulas (L1<-39a) or (L1<-40a), wherein the linkage to the bridge V or the bridge of formula (2) or (3) is effected via the position marked "o". the symbols used have the meanings mentioned above.

[0077] The partial ligand of formula (L 1< -39) or (L 1< -40) is particularly preferably structured according to one of the following formulas (L 1< -39a') or (L 1< -40a'), the symbols used have the meanings mentioned above.

[0078] The R groups on the partial ligand L1< of formula (L1<-39) or (L1<-40) or the preferred embodiments are preferably selected from the group consisting of H, D, CN, OR1<, a straight-chain alkyl group with 1 to 6 carbon atoms, preferably with 1, 2, or 3 carbon atoms, or a branched or cyclic alkyl group with 3, 4, 5, or 6 carbon atoms, or an alkenyl group with 2 to 6 carbon atoms, preferably with 2, 3, or 4 carbon atoms, each of which may be substituted by one or more R1< groups, or a phenyl group which may be substituted by one or more non-aromatic R1< groups. Two or more adjacent R groups may also form a ring system with each other.

[0079] The substituent R, which is bonded in the ortho position to the coordinating atom, is preferably selected from the group consisting of H, D, F or methyl, particularly preferably H, D or methyl and especially H or D.

[0080] Furthermore, it is preferred if all substituents R that are in ortho position to R' stand for H or D.

[0081] When R groups on the partial ligand L1 of formula (L1<-39) or (L1<-40) form a ring system, it is preferably an aliphatic, heteroaliphatic, or heteroaromatic ring system. Furthermore, ring formation between two R groups on the two rings of the partial ligand L1 is preferred, preferably forming a phenanthridine or a phenanthridine which may contain further nitrogen atoms. When R groups form a heteroaromatic ring system, a structure is preferably formed which is selected from the group consisting of quinoline, isoquinoline, dibenzofuran, dibenzothiophene, and carbazole, each of which may be substituted by one or more R< groups, and wherein in dibenzofuran, dibenzothiophene, and carbazole, individual carbon atoms may also be replaced by nitrogen. Quinoline, isoquinoline, dibenzofuran, and azadibenzofuran are particularly preferred.The fused structures can be bound in any possible position. Preferred partial ligands L1< with fused benzo groups are the structures listed below, formula (L1< -39b) to (L1< -40e), where the linkage to the bridge V occurs via the position marked "o": . wherein the subligands may each be substituted by one or more further residues R and the condensed structure may be substituted by one or more residues R< 1<. Preferably no further residues R or R< 1< are present.

[0082] Preferred partial ligands L 1< of formula (L 1< -39) or (L 1< -40) with fused benzofuran or azabenzofuran group are the structures listed below, formula (L 1< -39f) to (L 1< -40m), where the linkage to the bridge V occurs via the position marked by "o": wherein the ligands may each be substituted by one or more further residues R and the condensed structure may be substituted by one or more residues R< 1<. Preferably no further residues R or R< 1< are present. Likewise, O in these structures may be replaced by S or NR< 1<.

[0083] As described above, R' is a group of formula (16) or (17). The two groups differ only in that the group of formula (16) is linked to the subligand L 1< in the para-position and the group of formula (17) in the meta-position.

[0084] In a preferred embodiment of the invention, n = 0, 1 or 2, preferably 0 or 1 and most preferably 0.

[0085] In a further preferred embodiment of the invention, both substituents R", which are bonded in the ortho positions to the carbon atom to which the group of formula (16) or (17) is bonded to the phenylpyridine ligand, are the same or different H or D.

[0086] Preferred embodiments of the structure of formula (16) are the structures of formulas (16a) to (16h), and preferred embodiments of the structure of formula (17) are the structures of formulas (17a) to (17h), where E stands for O, S, C(R 1< ) 2 or NR 1< and the other symbols used have the meanings mentioned above. R 1< for E = NR 1< preferably represents an aromatic or heteroaromatic ring system with 6 to 18 aromatic ring atoms, which may be substituted by one or more R 2< groups, but is preferably unsubstituted. Furthermore, R 1< for E = C(R 1< ) 2 preferably represents, in each instance the same or different form, an alkyl group with 1 to 6 carbon atoms, preferably with 1 to 4 carbon atoms, and particularly preferably methyl groups.

[0087] Preferred substituents R' on the groups of formula (16) or (17) or the preferred embodiments are selected from the group consisting of H, D, CN and an alkyl group with 1 to 4 C atoms, particularly preferably H, D, Methyl, Cyclopentyl, 1-Methylcyclopentyl, Cyclohexyl or 1-Methylcyclohexyl, especially H, D or Methyl.

[0088] The monodentate subligands L2< and L3< are described below. L2< and L3< can be the same or different, representing either a neutral or a monoanionic subligand in each instance.

[0089] In a preferred embodiment of the present invention, L2< and L3< represent, in each instance, an aryl or heteroaryl group comprising 5 to 13 aromatic ring atoms, particularly preferably 6 to 13 aromatic ring atoms, and most preferably 6 to 10 aromatic ring atoms. This group coordinates to the iridium via a carbon or nitrogen atom, which is part of the aryl or heteroaryl group, respectively, and may be substituted with one or more R groups. If the group coordinates to the iridium via a carbon atom, this carbon atom may be anionic or a neutral carbene carbon atom. If the group coordinates to the iridium via a nitrogen atom, this nitrogen atom may be neutral or anionic.

[0090] Preferred embodiments of L 2< and L 3< are the same or different in each occurrence the structures of the following formulas (L 2< -1) respectively.

[0091] (L 3< -1) to (L 2< -55) or (L 3< -55), wherein the group is coordinated to the iridium at the position marked by * and to the bridgehead V or to the group of formula (2) or (3) at the position marked by "o", where R has the meanings mentioned above and the following applies to the other symbols used: X is the same or different CR or N for each occurrence, with the proviso that a maximum of two symbols X per cycle represent N; Wist is the same or different NR, O or S for each occurrence.

[0092] The groups (L 2< -1) and (L 3< -1) to (L 2< -22) and (L 3< -22) coordinate via an anionic carbon atom, the groups (L 2< -23) and (L 3< -23) to (L 2< -26) and (L 3< -26) and (L 2< -34) to (L 2< -50) and (L 3< -50) coordinate via a neutral nitrogen atom, the groups (L 2< -27) and (L 3< -27) to (L 2< -33) and (L 3< -33) coordinate via a neutral carbene carbon atom, and the groups (L 2< -51) and (L 3< -51) to (L 2< -55) and (L 3< -55) coordinate via a anionic nitrogen atom to the iridium.

[0093] Preferably, at most one symbol X represents N, and most preferably all symbols X represent CR.

[0094] Particularly preferred groups L 2< and L 3< are the groups of the following formulas (L 2< -1a) and (L 3< -1a) to (L 2< -55a) and (L 3< -55a), The symbols used have the meanings mentioned above. Preferably, there are a maximum of three substituents R other than H or D, particularly preferably a maximum of two substituents R, and most preferably a maximum of one substituent R.

[0095] Preferred monodentate partial ligands L 2 < and L 3 < are the structures (L 2 < -1), (L 3 < -1), (L 2 < -23), (L 3 < -23), (L 2 < -27), (L 3 < -27), (L 2 < -28), (L 3 < -28), (L 2 < -32), (L 3 < -32), (L 2 < -33) and (L 3< -33). Particularly preferred monodentate partial ligands L 2< and L 3< are the structures (L 2<-1a), (L 3<-1a), (L 2<-23a), (L 3<-23a), (L 2<-27a), (L 3<-27a), (L 2<-28a), (L 3<-28a), (L 2<-32a), (L 3< -32a), (L 2< -33a), (L 3< -33a), (L 2< -33b) and (L 3< -33b).

[0096] Preferred embodiments for ligand L4< are described below. As described above, L4< can be monodentate or bidentate. If ligand L4< is monodentate, it can be neutral or monoanionic. If ligand L4< is bidentate, it can be neutral, monoanionic, or dianionic. If ligand L4< is monodentate, it preferably coordinates via atoms that are either identical or different from the group consisting of carbon, nitrogen, oxygen, sulfur, and phosphorus. If ligand L4< is bidentate, it preferably coordinates via two atoms that are either identical or different from the group consisting of carbon, nitrogen, oxygen, sulfur, and phosphorus.

[0097] Suitable neutral, monodentate ligands L4< are selected from the group consisting of carbon monoxide (CO), nitric oxide (NO), alkyl cyanides such as acetonitrile, aryl cyanides such as benzonitrile, alkyl isocyanides such as methyl isonitrile, tert-butyl isonitrile, adamantyl isonitrile, aryl isocyanides such as phenyl isonitrile, amines such as trimethylamine, triethylamine, morpholine, phosphines, in particular halophosphines, trialkylphosphines, triarylphosphines or alkylarylphosphines such as trifluorophosphine, trimethylphosphine, tricyclohexylphosphine, tri- tert -butylphosphine, triphenylphosphine, tris(pentafluorophenyl)phosphine, dimethylphenylphosphine, methyldiphenylphosphine, bis(tert-butyl)phenylphosphine, phosphites, such as. B. trimethyl phosphite, triethyl phosphite, arsines, such as. B. trifluoroarsine, trimethylarsine, tricyclohexylarsine, tri- tert-butylarsine, triphenylarsine, tris(pentafluorophenyl)arsine, stibines, such as trifluorosibin, trimethylstibin, tricyclohexylstibin, tri- tert -butylstibine, triphenylstibine, tris(pentafluorophenyl)stibine, nitrogen-containing heterocycles such as pyridine, pyridazine, pyrazine, pyrimidine, triazine, and carbenes, especially arduengo-carbenes. Preferred monodentate neutral ligands L4< are selected from the group consisting of CO, PF3, and trialkylphosphines, wherein the alkyl groups have the same or different numbers of 1 to 10 carbon atoms in each case.

[0098] Suitable monoanionic, monodentate ligands L4< are selected from the following, either identical or different at each occurrence: hydride, deuteride, the halides F⁻, Cl⁻, Br⁻ and I⁻, alkylacetylides such as methyl C≡C⁻, tert-butyl C≡C⁻, arylacetylides such as phenyl C≡C⁻, cyanide, cyanate, isocyanate, thiocyanate, isothiocyanate, aliphatic or aromatic alcoholates such as methoxide, ethanolate, propanolate. ISO -Propanolate, tert -Butylate, phenolate, aliphatic or aromatic thioalcoholates, such as methanethiolate, ethanethiolate, propanethiolate, ISO -Propanethiolate tert- Thiobutylate, thiophenolate, amides, such as. B. dimethylamide, diethylamide, di- ISO-propylamide, morpholide, carboxylates such as acetate, trifluoroacetate, propionate, benzoate, aryl groups such as phenyl, naphthyl, and anionic, nitrogen-containing heterocycles such as pyrrolide, imidazolide, pyrazolide. The alkyl groups in these groups are preferably C1-C20 alkyl groups, particularly preferably C1-C10 alkyl groups, and most preferably C1-C4 alkyl groups. Heteroaryl groups are also considered to be aryl groups. These groups are defined as above. A preferred monodentate monoanionic ligand L4< is CN.

[0099] Preferred neutral or mono- or dianionic, bidentate ligands L4< are selected from diamines, such as ethylenediamine, N,N,N',N'-tetramethylethylenediamine, propylenediamine, N,N,N',N'-tetramethylpropylenediamine, cis- or trans-diaminocyclohexane, cis- or trans-N,N,N',N'-tetramethyldiaminocyclohexane, imines, such as 2-[1-(phenylimino)ethyl]pyridine, 2-[1-(2-methylphenylimino)ethyl]pyridine, 2-[1-(2,6-di- ISO -propyl-phenylimino)ethyl]pyridine, 2-[1-(Methylimino)ethyl]pyridine, 2-[1-(ethylimino)-ethyl]pyridine, 2-[1-( Iso -Propylimino)ethyl]pyridine, 2-[1-( Tert -Butylimino)-ethyl]pyridine, diimines, such as 1,2-bis(methylimino)ethane, 1,2-bis(ethyl-imino)ethane, 1,2-bis( ISO -propylimino)ethane, 1,2-Bis( tert -butylimino)ethane, 2,3-Bis(methylimino)butane, 2,3-Bis(ethylimino)butane, 2,3-Bis( ISO -propyl-imino)butane, 2,3-Bis( tert -butylimino)butane, 1,2-Bis(phenylimino)ethane, 1,2-Bis(2-methylphenylimino)ethane, 1,2-Bis(2,6-di- ISO -propylphenylimino)ethane, 1,2-Bis(2,6-di- tert -butylphenylimino)ethane, 2,3-Bis(phenylimino)butane, 2,3-Bis(2-methylphenylimino)butane, 2,3-Bis(2,6-di- ISO -propylphenyl-imino)butane, 2,3-bis(2,6-di- tert -butylphenylimino)butane, heterocycles containing two nitrogen atoms, such as 2,2'-bipyridine, o-phenanthroline, diphosphines, such as bis(diphenylphosphino)methane, bis(diphenylphosphino)ethane, bis(diphenylphosphino)propane, bis(diphenylphosphino)butane, bis(dimethylphosphino)methane, bis(dimethylphosphino)ethane, bis-(dimethylphosphino)propane, bis(diethylphosphino)methane, bis(diethylphosphino)ethane, bis(diethylphosphino)propane, bis(di- tert -butylphosphino)methane, Bis(di- tert -butylphosphino)ethane, Bis( tert-butylphosphino)propane, 1,3-diketonates derived from 1,3-diketones, such as acetylacetone, benzoylacetylacetone, 1,5-diphenylacetylacetone, dibenzoylmethane, bis-(1,1,1-trifluoroacetyl)methane, 3-ketoates derived from 3-ketoesters, such as ethyl acetoacetic acid ester, carboxylates derived from aminocarboxylic acids, such as pyridine-2-carboxylic acid, quinoline-2-carboxylic acid, glycine, N,N-dimethylglycine, alanine, N,N-dimethylaminoalanine, salicylimates derived from salicylic acid mints, such as methyl salicylic acid mint, ethyl salicylic acid mint, phenyl salicylic acid mint, dialcoholates derived from dialcohols, such as... B. Ethylene glycol, 1,3-propylene glycol, dithiolates derived from dithiols, such as 1,2-ethylenedithiol, 1,3-propylenedithiol, bis(pyrazolyl borates), bis-(imidazolyl)borates, 3-(2-pyridyl)diazoles or 3-(2-pyridyl)triazoles.

[0100] Preferred are bidentate monoanionic, neutral, or dianionic ligands L4<, in particular monoanionic ligands which, with the iridium, form a cyclometallated five-membered or six-membered ring with at least one iridium-carbon bond, especially a cyclometallated five-membered ring. These are, in particular, ligands such as those commonly used in the field of phosphorescent metal complexes for organic electroluminescence devices, i.e., ligands of the type phenylpyridine, naphthylpyridine, phenylquinoline, phenylisoquinoline, etc., each of which may be substituted by one or more R groups. A multitude of such ligands are known to those skilled in the art in the field of phosphorescent electroluminescence devices, and they can select further such ligands as ligand L4< for compounds according to formula (1) without any inventive effort.

[0101] Suitable bidentate ligands L 4< are selected from the ligands of the following formulas (L 4< -1), (L 4< -2) and (L 4< -3), where the following applies to the symbols used: CyC is, in each occurrence, a substituted or unsubstituted aryl or heteroaryl group with 5 to 14 aromatic ring atoms, each coordinated to the metal via a carbon atom and connected to CyD via a covalent bond; CyD is, in each occurrence, a substituted or unsubstituted heteroaryl group with 5 to 14 aromatic ring atoms, coordinated to the metal via a nitrogen atom or a carbene carbon atom and connected to CyC via a covalent bond; Several of the optional substituents can form a ring system together; the optional residues are preferably selected from the residues R mentioned above.

[0102] CyD coordinates via a neutral or anionic nitrogen atom or via a carbene carbon atom. CyC coordinates via an anionic carbon atom.

[0103] If several of the substituents, especially several R groups, form a ring system together, the formation of a ring system from substituents bonded to directly adjacent carbon atoms is possible. Furthermore, it is also possible for the substituents on CyC and CyD to form a ring together, whereby CyC and CyD can also together form a single fused aryl or heteroaryl group as a bidentate partial ligand.

[0104] In a preferred embodiment of the present invention, CyC is an aryl or heteroaryl group with 6 to 13 aromatic ring atoms, particularly preferably with 6 to 10 aromatic ring atoms, most preferably with 6 aromatic ring atoms, which is coordinated to the metal via a carbon atom, which may be substituted with one or more R groups and which is connected to CyD via a covalent bond.

[0105] Preferred embodiments of the CyC group are the structures of the following formulas (CyC-1) to (CyC-20), wherein the CyC group binds to CyD at the position marked by # and coordinates to the iridium at the position marked by *. where R has the meanings mentioned above and the following applies to the other symbols used: X is the same or different CR or N for each occurrence, with the proviso that a maximum of two symbols X per cycle represent N; Wist is the same or different NR, O or S for each occurrence.

[0106] Preferably, at most one symbol X in CyC represents N, and most preferably all symbols X represent CR.

[0107] Particularly favored groups CyC are the groups of the following formulas (CyC-1a) to (CyC-20a), where the symbols used have the meanings mentioned above. Preferably, a maximum of three substituents R are not equal to H or D, Particularly preferably a maximum of two substituents R and most preferably a maximum of one substituent.

[0108] Preferred groups among groups (CyC-1) to (CyC-20) are groups (CyC-1), (CyC-3), (CyC-8), (CyC-10), (CyC-12), (CyC-13) and (CyC-16), and especially preferred are groups (CyC-1a), (CyC-3a), (CyC-8a), (CyC-10a), (CyC-12a), (CyC-13a) and (CyC-16a).

[0109] In In another preferred embodiment of the invention, CyD is a heteroaryl group comprising 5 to 13 aromatic ring atoms, particularly preferably comprising 6 to 10 aromatic ring atoms, which is coordinated to the metal via a neutral nitrogen atom or via a carbene carbon atom and which may be substituted with one or more R groups and which is connected to CyC via a covalent bond.

[0110] Preferred embodiments of the CyD group are the structures of the following formulas (CyD-1) to (CyD-21), wherein the CyD group binds to CyC at the position marked by # and coordinates to the iridium at the position marked by *. where X, Wund R have the meanings mentioned above.

[0111] In this process, groups (CyD-1) to (CyD-4) and (CyD-7) to (CyD-18) coordinate to the metal via a neutral nitrogen atom, (CyD-5) and (CyD-6) via a carbene carbon atom and (CyD-19) to (CyD-21) via an anionic nitrogen atom.

[0112] Preferably, at most one symbol X in CyD represents N, and especially preferably all symbols X represent CR.

[0113] Particularly favored groups CyD are the groups of the following formulas (CyD-1a) to (CyD-21a), where the symbols used have the meanings mentioned above. Preferably, a maximum of three substituents R are not equal to H or D, Particularly preferably a maximum of two substituents R and most preferably a maximum of one substituent.

[0114] Preferred groups among groups (CyD-1) to (CyD-12) are groups (CyD-1), (CyD-2), (CyD-3), (CyD-4), (CyD-5) and (CyD-6), in particular (CyD-1), (CyD-2) and (CyD-3), and especially preferred are groups (CyD-1a), (CyD-2a), (CyD-3a), (CyD-4a), (CyD-5a) and (CyD-6a), in particular (CyD-1a), (CyD-2a) and (CyD-3a).

[0115] InIn a preferred embodiment of the invention, CyC is an aryl or heteroaryl group with 6 to 13 aromatic ring atoms, and CyD is simultaneously a heteroaryl group with 5 to 13 aromatic ring atoms. Particularly preferred is CyC an aryl or heteroaryl group with 6 to 10 aromatic ring atoms, and CyD a heteroaryl group with 5 to 10 aromatic ring atoms. Most particularly preferred is CyC an aryl or heteroaryl group with 6 aromatic ring atoms and CyD a heteroaryl group with 6 to 10 aromatic ring atoms. CyC and CyD can be substituted with one or more R groups.

[0116] The preferred groups (CyC-1) to (CyC-20) and (CyD-1) to (CyD-23) mentioned above can be combined with each other as desired. It is particularly preferred to combine the groups CyC and CyD mentioned above as especially preferred, i.e., the groups with formulas (CyC-1a) to (CyC-20a) and the groups with formulas (CyD1-a) to (CyD-14b). It is particularly preferred if one of the groups (CyC-1), (CyC-3), (CyC-8), (CyC-10), (CyC-12), (CyC-13) and (CyC-16), and especially the groups (CyC-1a), (CyC-3a), (CyC-8a), (CyC-10a), (CyC-12a), (CyC-13a) and (CyC-16a), is combined with one of the groups (CyD-1), (CyD-2) and (CyD-3), and especially with one of the groups (CyD-1a), (CyD-2a) and (CyD-3a).

[0117] Preferred ligands (L 4< -1) are the structures of the formulas (L 4< -1-1) to (L 4< -1-5), the symbols used have the meanings mentioned above.

[0118] Particularly favored subligands (L 4< -1) are the structures of the formulas (L 4< -1-1a) to (L 4< -1-5a), where the symbols used have the meanings mentioned above. Preferably, a maximum of three substituents R are not equal to H or D, Particularly preferably a maximum of two substituents R and most preferably a maximum of one substituent.

[0119] If two remains R, When one of the substituents is bonded to CyC and the other to CyD, forming an aromatic ring system, bridged ligands or ligands that together constitute a single larger heteroaryl group can result. Ring formation between the substituents on CyC and CyD is preferentially mediated by a group according to one of the formulas (5) to (14), as shown above for the partial ligand L1<.

[0120] Preferred ligands L 4< , which are formed by ring formation of two residues R on the different cycles, are the structures listed below with the formulas (L 4< -3) to (L 4< -16), the symbols used have the meanings mentioned above.

[0121] In a preferred embodiment of the partial ligands of formulas (L 4< -4) to (L 4< -16) one symbol X represents N and the other symbols X represent CR, or all symbols X represent CR.

[0122] In a further embodiment of the invention, it is preferred that, in groups (CyC-1) to (CyC-20) or (CyD-1) to (CyD-14) or in the partial ligands (L 4< -4) to (L 4< -16), if one of the atoms X represents N, a group R, which is not hydrogen or deuterium, is bonded as a substituent adjacent to this nitrogen atom. This applies analogously to the preferred structures (CyC-1a) to (CyC-20a) or (CyD-1a) to (CyD-14b), in which a group R, which is not hydrogen or deuterium, is preferably bonded as a substituent adjacent to a non-coordinating nitrogen atom.This substituent R is preferably a group selected from CF3, OCF3, alkyl groups with 1 to 10 carbon atoms, in particular branched or cyclic alkyl groups with 3 to 10 carbon atoms, OR1<, where R1< represents an alkyl group with 1 to 10 carbon atoms, in particular a branched or cyclic alkyl group with 3 to 10 carbon atoms, a dialkylamino group with 2 to 10 carbon atoms, aromatic or heteroaromatic ring systems, or aralkyl or heteroaralkyl groups. These groups are sterically demanding. Furthermore, this substituent R can preferably also form a cycle with a neighboring substituent R.

[0123] Another suitable bidentate ligand L 4< is a structure of the following formula (L 4< -17), where R has the meanings mentioned above, * represents the position of the coordination to iridium, and for the other symbols used: X is the same or different from CR or N in each occurrence, with the proviso that at most one symbol X per cycle stands for N.

[0124] Preferred embodiments of the ligand (L 4< -17) can be found in applications WO 2011 / 044988, WO 2014 / 094962, WO 2014 / 094961 and WO 2014 / 094960.

[0125] In a further embodiment of the invention, L is a ligand of the following formula (L 4< -18), which is coordinated to the iridium via the two positions marked with *, The symbols X, Z, R', R" and n have the same meanings as described above for the sub-ligands (L 1< -39) and (L 1< -40).

[0126] Preferred embodiments for the ligand (L 4< -18) are the same as described above for the sub-ligands (L 1< -39) and (L 1< -40).

[0127] A preferred embodiment of the ligand (L 4< -18) is the ligand of the following formula (L 4< -18a), the symbols used have the meanings mentioned above.

[0128] The ligand of formula (L 4< -18) particularly preferentially exhibits a structure according to the following formula (L 4< -18b), the symbols used have the meanings mentioned above.

[0129] The same applies to preferred residues R and R' on the ligand of formula (L 4< -18) or the preferred embodiments as described above for the partial ligands (L 1< -39) and (L 1< -40).

[0130] Preferred ligands L 4< with fused benzo groups are the following structures, formula (L 4< -18c) to (L 4< -18h): wherein the ligands may each be substituted by one or more further residues R and the condensed structure may be substituted by one or more residues R< 1<. Preferably no further residues R or R< 1< are present.

[0131] Preferred ligands L 4< of formula (L 4< -18) with fused benzofuran or azabenzofuran groups are the structures listed below, formula (L 4< -18i) to (L 4< -18y): wherein the ligands may each be substituted by one or more further residues R and the condensed structure may be substituted by one or more residues R< 1<. Preferably no further residues R or R< 1< are present. Likewise, O in these structures may be replaced by S or NR< 1<.

[0132] Preferred embodiments of the substituent R' of formula (16) or (17) in the ligand L 4< correspond to the preferred embodiments described above for (L 1< -39) and (L 1< -40).

[0133] Further embodiments of L 4< are the bidentate dianionic ligands (L 4< -19) and (L 4< -20) and the bidentate monoanionic ligands (L 4< -21) to (L 4< -24), which each coordinate to the iridium via the two atoms marked with *, where R has the meanings mentioned above and X, whether the same or different, represents CR or N in each occurrence, provided that no more than two Xs represent N. Preferably, no more than one X represents N, and most preferably, all Xs, whether the same or different, represent CR in each occurrence.

[0134] The preferred ligands are (L 4< -19a) to (L 4< -24a), where R has the meanings mentioned above. Preferably, there are a maximum of three substituents R other than H or D, particularly preferably a maximum of two substituents R, and most particularly preferably a maximum of one substituent.

[0135] Preferred substituents are described below, as they can be present on the partial ligands L1<, L2< and / or L3< or the ligand L4< described above. These substituents can also be present on the bivalent arylene or heteroarylene group in the structures of formula (4).

[0136] In a preferred embodiment of the invention, the metal complex according to the invention comprises two substituents R or two substituents R< 1< which are bonded to adjacent carbon atoms and which together form an aliphatic ring according to one of the formulas described below. The two substituents R forming this aliphatic ring can be located at bridge V or the bridge of formula (2) or (3), and / or at the bidentate partial ligand and / or at one of the monodentate partial ligands. The aliphatic ring formed by the ring formation of two substituents R together or of two substituents R< 1< is preferably described by one of the following formulas (18) to (24). where R 1< and R 2< have the meanings mentioned above, the dashed bonds indicate the linkage of the two carbon atoms in the ligand, and furthermore: Gist is an alkylene group with 1, 2 or 3 carbon atoms, which may be substituted with one or more R 2< substituents, -CR 2< =CR 2< - or an ortho-linked arylene or heteroarylene group with 5 to 14 aromatic ring atoms, which may be substituted by one or more R 2< substituents;R3< is the same or different at each occurrence H, F, a straight-chain alkyl or alkoxy group with 1 to 10 C atoms, a branched or cyclic alkyl or alkoxy group with 3 to 10 C atoms, wherein the alkyl or alkoxy group may each be substituted with one or more R2< residues, wherein one or more non-adjacent CH2 groups may be replaced by R2< C=CR2< , C=C, Si(R2< )2 , C=O, NR2< , O, S or CONR2< , or an aromatic or heteroaromatic ring system with 5 to 24 aromatic ring atoms, each of which may be substituted by one or more R2< residues, or an aryloxy or heteroaryloxy group with 5 to 24 aromatic ring atoms, which may be substituted by one or more R2< residues can be substituted; in this case, two R 3< residues, which are bonded to the same carbon atom, can form an aliphatic or aromatic ring system together and thus span a spiro system;Furthermore, R<3 can form an aliphatic ring system with a neighboring residue R or R<1.

[0137] If neighboring residues in the structures according to the invention form an aliphatic ring system, it is preferred that this system does not contain acidic benzylic protons. Benzylic protons are understood to be protons that bind to a carbon atom that is directly bonded to the ligand. This can be achieved by ensuring that the carbon atoms of the aliphatic ring system that bind directly to an aryl or heteroaryl group are fully substituted and do not contain any bonded hydrogen atoms. Thus, the absence of acidic benzylic protons in formulas (18) to (24) is achieved by ensuring that R3 is not equal to hydrogen. This can also be achieved by having the carbon atoms of the aliphatic ring system that bind directly to an aryl or heteroaryl group be the bridgeheads of a bicyclic or polycyclic structure.Due to the spatial structure of the bi- or polycyclic structure, the protons bound to bridgehead carbon atoms are significantly less acidic than benzylic protons bound to carbon atoms not in a bi- or polycyclic structure and are considered non-acidic protons within the meaning of the present invention. Thus, the absence of acidic benzylic protons in formulas (21) to (24) is achieved by using a bicyclic structure, whereby R<1, when representing H, is significantly less acidic than benzylic protons because the corresponding anion of the bicyclic structure is not resonance-stabilized. Therefore, even when R<1 represents H in formulas (21) to (24), it is a non-acidic proton within the meaning of the present application. In a preferred embodiment of the invention, R<3 is not equal to H.

[0138] Preferred embodiments of the groups of formulas (18) to (24) can be found in applications WO 2014 / 023377, WO 2015 / 104045 and WO 2015 / 117718.

[0139] If the compounds according to the invention have residues R that do not correspond to the residues R described above, these residues R are, in each occurrence, the same or different, preferably selected from the group consisting of H, D, F, Br, I, N(R 1< ) 2 , CN, Si(R 1< ) 3 , B(OR 1< ) 2 , C(=O)R', a straight-chain alkyl group with 1 to 10 C atoms or an alkenyl group with 2 to 10 C atoms or a branched or cyclic alkyl group with 3 to 10 C atoms, wherein the alkyl or alkenyl group may each be substituted with one or more residues R 1< , or an aromatic or heteroaromatic ring system with 5 to 30 aromatic ring atoms, each of which may be substituted by one or more residues R 1< ; Two adjacent residues R or R with R 1< can also form a mono- or polycyclic, aliphatic or aromatic ring system together.Particularly preferred are these residues R, in each occurrence the same or different, selected from the group consisting of H, D, F, N(R 1< ) 2 , a straight-chain alkyl group with 1 to 6 C atoms or a branched or cyclic alkyl group with 3 to 10 C atoms, wherein one or more H atoms may be replaced by D or F, or an aromatic or heteroaromatic ring system with 5 to 24 aromatic ring atoms, each of which may be substituted by one or more residues R 1< ; in this respect, two adjacent residues R or R with R 1< may also form a mono- or polycyclic, aliphatic or aromatic ring system together.

[0140] Preferred residues R 1< bonded to R are, at each occurrence, the same or different: H, D, F, N(R 2< ) 2 , CN, a straight-chain alkyl group with 1 to 10 C atoms or an alkenyl group with 2 to 10 C atoms or a branched or cyclic alkyl group with 3 to 10 C atoms, wherein the alkyl group may be substituted with one or more residues R 2<, or an aromatic or heteroaromatic ring system with 5 to 24 aromatic ring atoms, each of which may be substituted by one or more residues R 2<; in this respect, two or more adjacent residues R 1< may form a mono- or polycyclic aliphatic ring system.Particularly preferred residues R 1< bonded to R are, in each occurrence, the same or different H, F, CN, a straight-chain alkyl group with 1 to 5 C atoms or a branched or cyclic alkyl group with 3 to 5 C atoms, each of which may be substituted with one or more residues R 2<, or an aromatic or heteroaromatic ring system with 5 to 13 aromatic ring atoms, each of which may be substituted by one or more residues R 2<; in this respect, two or more adjacent residues R 1< may together form a mono- or polycyclic, aliphatic ring system.

[0141] Preferred residues R 2< are the same or different in each occurrence H, F or an aliphatic hydrocarbon residue with 1 to 5 C atoms or an aromatic hydrocarbon residue with 6 to 12 C atoms; two or more substituents R 2< can also form a mono- or polycyclic, aliphatic ring system together.

[0142] The preferred embodiments mentioned above can be combined with each other as desired. In In a particularly preferred embodiment of the invention, the above-mentioned preferred embodiments apply simultaneously.

[0143] Examples of suitable structures according to the invention are the compounds shown below. 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 79 71 72 73 74 75 76 77 78 79 80 81 82

[0144] The compounds according to the invention can, in principle, be prepared by various methods. Generally, an iridium compound is reacted in a first step with the corresponding free tetradentate ligand. The intermediate thus obtained is then reacted with the monodentate or the bidentate ligand to form the product. This is illustrated below using the example of a simple tetradentate ligand with one monoanionic partial ligand L1< and two neutral partial ligands L2< and L3< in combination with two monoanionic ligands L4< or one dianionic ligand L4<.

[0145] Therefore, a further object of the present invention is a process for the preparation of the compounds according to the invention by reacting the corresponding free tetradentate ligands with iridium alcoholates of formula (25), with iridium ketoketonates of formula (26), with iridium halides of formula (27), with iridium carboxylates of formula (28), iridium olefin cyclopentadienyl complexes of formula (29) or with iridium olefin indenyl complexes of formula (30), and subsequent reaction of the intermediate thus obtained with the ligand(s) L 4< . Here, R has the meanings given above, Hal = F, Cl, Br or I, and the iridium reactants can also exist as the corresponding hydrates. R preferably represents an alkyl group with 1 to 4 carbon atoms. Olefin in formulas (29) and (30) represents a diolefin, typically 1,5-cyclooctadiene, but also other diolefins such as cyclohexadiene or norbornadiene.

[0146] Iridium compounds bearing both alcoholate and / or halide and / or hydroxy as well as ketoketonate groups can also be used. These compounds can also be charged. Suitable iridium compounds, particularly appropriate as starting materials, are disclosed in WO 2004 / 085449. Particularly suitable are [IrCl₂(acac)₂]⁻, for example Na[IrCl₂(acac)₂], metal complexes with acetylacetonate derivatives as ligands, for example Ir(acac)₃ or Tris(2,2,6,6-tetramethylheptane-3,5-dionato)iridium, and IrCl₃·xH₂O, where x usually represents a number between 2 and 4.

[0147] The synthesis of the complexes is preferably carried out as described in WO 2002 / 060910 and WO 2004 / 085449. The synthesis can, for example, be activated thermally, photochemically, and / or by microwave radiation. Furthermore, the synthesis can also be carried out in an autoclave at elevated pressure and / or temperature.

[0148] The reactions can be carried out without the addition of solvents or melting aids in a melt of the ligands to be orthometallated. Solvents or melting aids can also be added if necessary. Suitable solvents are protic or aprotic solvents, such as aliphatic and / or aromatic alcohols (methanol, ethanol, isopropanol, t-butanol, etc.), oligo- and polyalcohols (ethylene glycol, 1,2-propanediol, glycerin, etc.), alcohol ethers (ethoxyethanol, diethylene glycol, triethylene glycol, polyethylene glycol, etc.), ethers (di- and triethylene glycol dimethyl ether, diphenyl ether, etc.), aromatic, heteroaromatic and / or aliphatic hydrocarbons (toluene, xylene, mesitylene, chlorobenzene, pyridine, lutidine, quinoline, isoquinoline, tridecane, hexadecane, etc.), amides (DMF, DMAC, etc.), lactams (NMP), sulfoxides (DMSO) or sulfones (dimethyl sulfone, sulfolane, etc.).Suitable melting aids are compounds that are solid at room temperature but melt when the reaction mixture is heated, dissolving the reactants and forming a homogeneous melt. Particularly suitable are biphenyl, m-terphenyl, triphenylene, R- or S-binaphthol or the corresponding racemate, 1,2-, 1,3- or 1,4-bisphenoxybenzene, triphenylphosphine oxide, 18-crown-6, phenol, 1-naphthol, hydroquinone, catechol, resorcinol, etc. The use of hydroquinone is especially preferred.

[0149] Furthermore, the synthesis can preferably be carried out in anhydrous medium in the presence of a carboxylic acid, as described in the unpublished application EP19187468.4, wherein the iridium starting material is preferably an iridium halide, an iridium carboxylate, a COD-iridium(I) compound, an iridium ketoketonate, or a compound according to one of the above-mentioned formulas (25) to (30). Particularly suitable carboxylic acids are selected from the group consisting of acetic acid, propionic acid, pivalic acid, benzoic acid, phenylacetic acid, adipic acid, or mixtures thereof. When using a hydrate as the iridium starting material, a water scavenger is preferably added, in particular a carboxylic anhydride, a carboxylic halide, a trialkyl orthocarboxylate, a carbodiimide, phosphorus pentoxide, thionyl chloride, or phosphoryl chloride.When using a halide as an iridium reactant, a halide scavenger is preferably added, in particular an alkali, alkaline earth, ammonium or zinc salt of a carboxylic acid.

[0150] When ligands with two identical sub-ligands L2< and L3< are used in ortho-metallation, a racemic mixture of the C1-symmetric complexes, i.e., the Δ- and A-enantiomers, is typically formed. These can be separated by common methods (chromatography on chiral materials / columns or racemate separation by crystallization).

[0151] When ligands with different sub-ligands L 2< and L 3< are used in the complexation, a diastereomeric mixture of the complexes is usually formed, which can be separated by common methods (chromatography, crystallization, etc.).

[0152] By these methods, optionally followed by purification, such as recrystallization or sublimation, the compounds according to the invention can be obtained in high purity, preferably more than 99% (determined by 1< H-NMR and / or HPLC).

[0153] The compounds according to the invention can also be made soluble by suitable substitution, for example by longer alkyl groups (approximately 4 to 20 carbon atoms), in particular branched alkyl groups, or optionally substituted aryl groups, for example xylyl, mesityl, or branched terphenyl or quaterphenyl groups. In particular, the use of fused aliphatic groups, as represented, for example, by formulas (44) to (50) disclosed above, leads to a significant improvement in the solubility of the metal complexes. Such compounds are then soluble in common organic solvents, such as toluene or xylene, at room temperature in sufficient concentration to allow the complexes to be processed from solution. These soluble compounds are particularly well suited for processing from solution, for example, by printing processes.

[0154] For processing the iridium complexes according to the invention from the liquid phase, for example by spin coating or by printing processes, formulations of the iridium complexes according to the invention are required. These formulations can be, for example, solutions, dispersions, or emulsions. It may be preferred to use mixtures of two or more solvents for this purpose. Suitable and preferred solvents include, for example, toluene, anisole, o-, m- or p-xylene, methyl benzoate, mesitylene, tetralin, veratrol, THF, methyl-THF, THP, chlorobenzene, dioxane, phenoxytoluene, in particular 3-phenoxytoluene, (-)-fenchone, 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, 1-methylnaphthalene, 2-methylbenzothiazole, 2-phenoxyethanol, 2-pyrrolidinone, 3-methylanisole, 4-methylanisole, 3,4-dimethylanisole, 3,5-dimethylanisole, acetophenone, α-terpineol, benzothiazole, butyl benzoate, cumene, cyclohexanol, cyclohexanone, cyclohexylbenzene, decalin. Dodecylbenzene, ethyl benzoate, indane, NMP, p-cymene,Phenetol, 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, Hexamethylindane, 2-Methylbiphenyl, 3-Methylbiphenyl, 1-Methylnaphthalene, 1-Ethylnaphthalene, Ethyl octanoate, Diethyl sebacic acid ester, Octyl octanoate, Heptylbenzene, Menthyl isovalerate, Cyclohexylhexanoate or mixtures of these solvents.

[0155] A further object of the present invention is therefore a formulation comprising at least one compound according to the invention and at least one further compound. The further compound can, for example, be a solvent, in particular one of the solvents mentioned above or a mixture of these solvents. The further compound can also be another organic or inorganic compound that is also used in the electronic device, for example, a matrix material. This further compound can also be polymeric.

[0156] The compound according to the invention can be used in the electronic device as an active component, preferably as an emitter in the emissive layer or as a hole or electron transport material in a hole- or electron-transporting layer, or as an oxygen sensitizer or as a photoinitiator or photocatalyst. A further object of the present invention is thus the use of a compound according to the invention in an electronic device or as an oxygen sensitizer or as a photoinitiator or photocatalyst. Enantiomerically pure iridium complexes according to the invention are suitable as photocatalysts for chiral photoinduced syntheses.

[0157] Another object of the present invention is an electronic device comprising at least one connection according to the invention.

[0158] An electronic device is understood to be a device comprising an anode, a cathode, and at least one layer, wherein this layer contains at least one organic or organometallic compound. The electronic device according to the invention thus comprises an anode, a cathode, and at least one layer containing at least one iridium complex according to the invention.Preferred electronic devices are selected from the group consisting of organic electroluminescent devices (OLEDs, PLEDs), 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), including both purely organic solar cells and dye-sensitized solar cells, organic optical detectors, organic photoreceptors, organic field-quench devices (O-FQDs), light-emitting electrochemical cells (LECs), oxygen sensors, or organic laser diodes (O-Lasers), containing at least one compound according to the invention in at least one layer. Compounds that emit in the infrared range are suitable for use in organic infrared electroluminescent devices and infrared sensors.Organic electroluminescent devices are particularly preferred. Active components are generally the organic or inorganic materials introduced between the anode and cathode, for example, charge injection, charge transport, or charge blocking materials, but especially emission materials and matrix materials. The compounds according to the invention exhibit particularly good properties as emission materials in organic electroluminescent devices. Organic electroluminescent devices are therefore a preferred embodiment of the invention. Furthermore, the compounds according to the invention can be used for the generation of singlet oxygen or in photocatalysis.

[0159] The organic electroluminescent device contains a cathode, anode, and at least one emitting layer. In addition to these layers, it may contain further layers, for example, one or more hole injection layers, hole transport layers, hole blocking layers, electron transport layers, electron injection layers, exciton blocking layers, electron blocking layers, charge generation layers, and / or organic or inorganic p / n junctions. It is possible that one or more hole transport layers are p-doped, for example with metal oxides such as MoO3 or WO3, or with (per)fluorinated electron-deficient aromatics or with electron-deficient cyano-substituted heteroaromatics (e.g., according to JP 4747558, JP 2006-135145, US 2006 / 0289882, WO 2012 / 095143), or with quinoid systems (e.g., according to EP1336208), or with Lewis acids, or with boranes (e.g.,according to US 2003 / 0006411, WO 2002 / 051850, WO 2015 / 049030) or with carboxylates of the elements of the 3rd, 4th or 5th main group (WO 2015 / 018539) and / or that one or more electron transport layers are n-doped.

[0160] Interlayers can also be inserted between two emitting layers. These interlayers may, for example, have an exciton-blocking function and / or control the charge balance in the electroluminescence device and / or generate charges (charge-generation layers, e.g., in layer systems with multiple emitting layers, such as in white-emitting OLED devices). However, it should be noted that not every one of these layers is necessarily present.

[0161] The organic electroluminescent device can contain one or more emitting layers. If multiple emission layers are present, they preferably exhibit several emission maxima between 380 nm and 750 nm, resulting in overall white emission. This means that different emitting compounds capable of fluorescence or phosphorescence are used in the emitting layers. Three-layer systems are particularly preferred, wherein the three layers exhibit blue, green, and orange or red emission (for the basic structure, see, for example, WO 2005 / 011013), as are systems comprising more than three emitting layers. A hybrid system is also possible, wherein one or more layers fluoresce and one or more other layers phosphoresce. Tandem OLEDs are a preferred embodiment.White emitting organic electroluminescent devices can be used for lighting applications or, with color filters, also for full-color displays.

[0162] In a preferred embodiment of the invention, the organic electroluminescence device contains the iridium complex according to the invention as an emitting compound in one or more emitting layers.

[0163] When the iridium complex according to the invention is used as an emitting compound in an emitting layer, it is preferably used in combination with one or more matrix materials. The mixture of the iridium complex according to the invention and the matrix material contains between 0.1 and 99 vol%, preferably between 1 and 90 vol%, particularly preferably between 3 and 40 vol%, and especially between 5 and 15 vol% of the iridium complex according to the invention, based on the total mixture of emitter and matrix material. Similarly, the mixture contains between 99.9 and 1 vol%, preferably between 99 and 10 vol%, particularly preferably between 97 and 60 vol%, and especially between 95 and 85 vol% of the matrix material, based on the total mixture of emitter and matrix material.

[0164] Suitable matrix materials for the compounds according to the invention are ketones, phosphine oxides, sulfoxides and sulfones, e.g. according to WO 2004 / 013080, WO 2004 / 093207, WO 2006 / 005627 or WO 2010 / 006680, triarylamines, carbazole derivatives, e.g. CBP (N,N-biscarba-zolylbiphenyl), m-CBP or the carbazole derivatives disclosed in WO 2005 / 039246, US 2005 / 0069729, JP 2004 / 288381, EP 1205527, WO 2008 / 086851 or US 2009 / 0134784, bridged carbazole derivatives, e.g. B. according to US 2009 / 0136779, WO 2010 / 050778, WO 2011 / 042107 or WO 2011 / 088877, biscarbazole derivatives, indolocarbazole derivatives, e.g. according to WO 2007 / 063754 or WO 2008 / 056746, indenocarbazole derivatives, e.g. according to WO 2010 / 136109 or WO 2011 / 000455, azacarbazoles, e.g. according to EP 1617710, EP 1617711, EP 1731584, JP 2005 / 347160, bipolar matrix materials, e.g. according to WO 2007 / 137725, silanes, e.g. B. according to WO 2005 / 111172, azaboroles or boron esters, e.g. according to WO 2006 / 117052, diazasyl derivatives, e.g. according to WO 2010 / 054729, diazaphosphole derivatives, e.g.according to WO 2010 / 054730, triazine derivatives, e.g. according to WO 2010 / 015306, WO 2007 / 063754 or WO 2008 / 056746, zinc complexes, e.g. according to EP 652273 or WO 2009 / 062578, dibenzofuran derivatives, e.g. according to WO 2009 / 148015, dibenzothiophene derivatives or triphenylene derivatives.

[0165] It may also be preferred to use several different matrix materials as a mixture, in particular at least one electron-conducting matrix material and at least one hole-conducting matrix material. A preferred combination is, for example, the use of an aromatic ketone, a triazine derivative, or a phosphine oxide derivative with a triarylamine derivative or a carbazole derivative as a mixed matrix for the metal complex according to the invention. Equally preferred is the use of a mixture of a charge-transporting matrix material and an electrically inert matrix material, which is not involved, or not to a significant extent, in charge transport, as described, for example, in WO 2010 / 108579.

[0166] Preferred biscarbazoles that can be used as matrix materials for the compounds according to the invention are the structures of the following formulas (31) and (32), where Ar 1< represents, equally or differently, an aromatic or heteroaromatic ring system with 5 to 40 aromatic ring atoms, preferably with 6 to 30 aromatic ring atoms, each of which may be substituted with one or more R groups, A 1< represents NR, CR 2, O or S, and R has the meanings mentioned above. In a preferred embodiment of the invention, A 1< represents CR 2.

[0167] Preferred embodiments of the compounds of formulas (31) and (32) are the compounds of the following formulas (31a) and (32a), the symbols used have the meanings mentioned above.

[0168] Examples of suitable compounds according to formula (31) or (32) are the compounds shown below.

[0169] Preferred dibenzofuran derivatives are the compounds of the following formula (33), where the oxygen can also be replaced by sulfur, resulting in a dibenzothiophene, L represents a single bond or an aromatic or heteroaromatic ring system with 5 to 30 aromatic ring atoms, which can also be substituted by one or more R groups, and R and Ar< have the meanings mentioned above. The two Ar< groups bonding to the same nitrogen atom, or an Ar< group and an L group bonding to the same nitrogen atom, can also be linked together, for example to form a carbazole.

[0170] Preferred carbazolamines are the structures of the following formulas (34), (35) and (36), where L represents an aromatic or heteroaromatic ring system with 5 to 30 aromatic ring atoms, which may be substituted with one or more R substituents, and R and Ar 1< have the meanings mentioned above.

[0171] Preferred triazine, quinazoline or pyrimidine derivatives, which can be used as a mixture together with the compounds according to the invention, are the compounds of the following formulas (37), (38) and (39), where Ar 1< and R have the meanings mentioned above.

[0172] The triazine derivatives of formula (37) and the quinazoline derivatives of formula (39) are particularly preferred, especially the triazine derivatives of formula (37).

[0173] In a preferred embodiment of the invention, Ar 1< in formulas (37), (38) and (38) is, in each occurrence, the same or different, an aromatic or heteroaromatic ring system with 6 to 30 aromatic ring atoms, in particular with 6 to 24 aromatic ring atoms, which may be substituted by one or more R groups.

[0174] Suitable aromatic or heteroaromatic ring systems Ar 1< are the same as those described above as embodiments for Ar 1< , Ar 2< and Ar 3<, in particular the structures Ar-1 to Ar-76.

[0175] Examples of suitable triazine compounds which can be used as matrix materials together with the compounds according to the invention are the compounds shown in the following table.

[0176] It is further preferred to use a mixture of two or more triplet emitters, in particular two or three triplet emitters, together with one or more matrix materials. The triplet emitter with the shorter-wavelength emission spectrum serves as a co-matrix for the triplet emitter with the longer-wavelength emission spectrum. For example, the metal complexes according to the invention can be combined with a shorter-wavelength metal complex, e.g., one emitting blue, green, or yellow light, as a co-matrix. Metal complexes according to the invention can also be used, for example, as a co-matrix for longer-wavelength emitting triplet emitters, for example, for red-emitting triplet emitters. It may also be preferred if both the shorter-wavelength and the longer-wavelength emitting metal complex are compounds according to the invention.A preferred embodiment using a mixture of three triplet emitters is in which two are used as co-hosts and one as the emitting material. These triplet emitters preferably have the emission colors green, yellow, and red or blue, green, and orange.

[0177] A preferred mixture in the emitting layer contains an electron-transporting host material, a so-called "wide bandgap" host material which, due to its electronic properties, is not involved or not significantly involved in charge transport in the layer, a co-doping agent which is a triplet transmitter which emits at a shorter wavelength than the compound according to the invention, and a compound according to the invention.

[0178] Another preferred mixture in the emitting layer contains an electron-transporting host material, a so-called "wide band gap" host material which, due to its electronic properties, is not involved or not significantly involved in charge transport in the layer, a hole-transporting host material, a co-doping element which is a triplet transmitter which emits at a shorter wavelength than the compound according to the invention, and a compound according to the invention.

[0179] The compounds according to the invention can also be used in other functions within the electronic device, for example as a hole transport material in a hole injection or transport layer, as a charge generation material, as an electron blocking material, as a hole blocking material, or as an electron transport material, for example in an electron transport layer. Likewise, the compounds according to the invention can be used as a matrix material for other phosphorescent metal complexes in an emitting layer.

[0180] Preferred cathodes include metals with low work functions, metal alloys, or multilayer structures made of different metals, such as alkaline earth metals, alkali metals, main group metals, or lanthanides (e.g., Ca, Ba, Mg, Al, In, Mg, Yb, Sm, etc.). Alloys of an alkali or alkaline earth metal and silver are also suitable, for example, a magnesium-silver alloy. In multilayer structures, additional metals with relatively high work functions, such as Ag, can be used, typically in combinations of these metals, such as Mg / Ag, Ca / Ag, or Ba / Ag. It may also be advantageous to insert a thin interlayer of a material with a high dielectric constant between a metallic cathode and the organic semiconductor.Suitable materials for this purpose include alkali metal or alkaline earth metal fluorides, as well as the corresponding oxides or carbonates (e.g., LiF, Li₂O, BaF₂, MgO, NaF, CsF, Cs₂CO₃, etc.). Organic alkali metal complexes, such as Liq (lithium quinolinate), are also suitable. The thickness of this layer is preferably between 0.5 and 5 nm.

[0181] Materials with a high work function are preferred as anodes. Preferably, the anode has a work function greater than 4.5 eV vs. vacuum. Metals with a high redox potential, such as Ag, Pt, or Au, are suitable for this purpose. Alternatively, metal / metal oxide electrodes (e.g., Al / Ni / NiO₂, Al / PtO₂) may also be preferred. For some applications, at least one of the electrodes must be transparent or semi-transparent to allow either the irradiation of the organic material (O-SC) or the extraction of light (OLED / PLED, O-LASER). Conductive mixed metal oxides are preferred anode materials in this context. Indium tin oxide (ITO) or indium zinc oxide (IZO) are particularly preferred. Conductive doped organic materials, especially conductive doped polymers such as PEDOT, PANI, or derivatives of these polymers, are also preferred.It is further preferred to apply a p-doped hole transport material as a hole injection layer to the anode, with suitable p-doping materials being metal oxides, for example MoO₃ or WO₃, or (per)fluorinated electron-deficient aromatics. Other suitable p-doping materials are HAT-CN (hexacyanohexaazatriphenylene) or the compound NPD9 from Novaled. Such a layer simplifies hole injection into materials with a deep HOMO, i.e., a large HOMO magnitude.

[0182] In the subsequent layers, all materials can generally be used as they are used for the layers according to the prior art, and the person skilled in the art can combine any of these materials in an electronic device with the materials according to the invention without inventive effort.

[0183] Suitable charge transport materials, such as those that can be used in the hole injection or hole transport layer or electron blocking layer or in the electron transport layer of the organic electroluminescence device according to the invention, are, for example, the compounds disclosed in Y. Shirota et al., Chem. Rev. 2007, 107(4), 953-1010 or other materials such as those used in these layers according to the prior art. Preferred hole transport materials that can be used in a hole transport, hole injection or electron blocking layer in the electroluminescence device according to the invention are indenofluorenamine derivatives (e.g. according to WO 06 / 122630 or WO 06 / 100896), the amine derivatives disclosed in EP 1661888, hexaazatriphenylene derivatives (e.g. according to WO 01 / 049806), amine derivatives with fused aromatics (e.g. according to US 5,061,569), the amine derivatives disclosed in WO 95 / 09147, monobenzoindenofluorenamines (e.g.according to WO 08 / 006449), dibenzoindenofluorenamines (e.g. according to WO 07 / 140847), spirobifluorene amines (e.g. according to WO 2012 / 034627, WO2014 / 056565), fluorene amines (e.g. according to EP 2875092, EP 2875699 and EP 2875004), spiro-dibenzopyran amines (e.g. EP 2780325) and dihydroacridine derivatives (e.g. according to WO 2012 / 150001).

[0184] The device is structured accordingly (depending on the application), contacted, and finally hermetically sealed, as the lifespan of such devices is drastically reduced in the presence of water and / or air.

[0185] A further preferred organic electroluminescent device is characterized in that one or more layers are coated using a sublimation process. The materials are deposited in vacuum sublimation systems at an initial pressure typically less than 10⁻⁵ mbar, preferably less than 10⁻⁶ mbar. It is also possible for the initial pressure to be even lower or higher, for example, less than 10⁻⁷ mbar.

[0186] A preferred method is an organic electroluminescence device, characterized in that one or more layers are coated using the OVPD (Organic Vapor Phase Deposition) process or by means of carrier gas sublimation. The materials are applied at a pressure between 10⁻⁵ mbar and 1 bar. A special case of this method is the OVJP (Organic Vapor Jet Printing) process, in which the materials are applied directly through a nozzle and thus structured (e.g., BMS Arnold et al., Appl. Phys. Lett. 2008, 92, 053301).

[0187] A further preferred organic electroluminescent device is characterized in that one or more layers are produced from a solution, e.g., by spin coating, or by any printing process, e.g., screen printing, flexographic printing, offset printing, or nozzle printing, but particularly preferably LITI (Light Induced Thermal Imaging, thermal transfer printing) or inkjet printing. Soluble compounds are required for this purpose, which can be obtained, for example, by suitable substitution.

[0188] The organic electroluminescence device can also be produced as a hybrid system by depositing one or more solution layers and evaporating one or more other layers. For example, it is possible to deposit an emitting layer containing a metal complex according to the invention and a matrix material from solution and then to evaporate a hole-blocking layer and / or an electron transport layer onto it in a vacuum.

[0189] These methods are generally known to those skilled in the art and can be applied by them without difficulty to organic electroluminescent devices containing compounds according to formula (1) or the preferred embodiments listed above.

[0190] The electronic devices according to the invention, in particular organic electroluminescent devices, exhibit high efficiency, a long service life, and low operating voltage. Furthermore, the compounds according to the invention are thermally very stable, and in particular those compounds with a not too high molecular weight, especially with a molecular weight up to approximately 1200 g / mol, can be sublimed readily and without decomposition.

[0191] These aforementioned advantages do not come at the expense of other electronic properties.

[0192] The invention is further explained by the following examples, without being intended to limit it. A person skilled in the art can, from these descriptions, produce further electronic devices according to the invention without any inventive effort and thus implement the invention in its entire claimed scope. Description of the characters

[0193] Figure 1 Figure 1 shows the X-ray structure of the complex Ir617 according to the invention, the synthesis of which is described in the following examples. Examples:

[0194] Unless otherwise stated, the following syntheses are carried out under a protective gas atmosphere in dried solvents. The metal complexes are additionally handled in the absence of light or under yellow light. The solvents and reagents can be obtained, for example, from Sigma-Aldrich or ABCR. The information in square brackets or the numbers given for individual compounds refer to the CAS numbers of the compounds known from the literature. For compounds that can exhibit several tautomeric, isomeric, enantiomeric, or diastereomeric forms, one form is shown as a representative example. A: Synthesis of synthons S: Example S1:

[0195]

[0196] A mixture of 18.2 g (50 mmol) 2,2'-(5-chloro-1,3-phenylene)-bis[4,4,5,5-tetramethyl-1,3,2-dioxaborolane [1417036-49-7], 28.3 g (100 mol) 1-bromo-2-iodobenzene, 31.8 g (300 mmol) sodium carbonate, 200 mL toluene, 100 mL ethanol, and 200 mL water is mixed with 788 mg (3 mmol) triphenylphosphine and then with 225 mg (1 mmol) palladium(II) acetate while stirring very well and is heated under reflux for 48 h. After cooling, the organic phase is separated, washed once with 300 mL water and once with 300 mL saturated saline solution, and dried over magnesium sulfate. The filtrate is filtered off the drying agent and concentrated completely under vacuum. The residue is flash chromatographed (Torrent column analyzer by A. Semrau). Yield: 16.5 g (39 mmol), 78%; Purity: approx. 97%, < ¹H NMR. Example S2:

[0197] Stage S2a:

[0198]

[0199] A well-stirred mixture of 23.9 g (100 mmol) 2-chloro-4-iodopyridine [153034-86-7], 19.8 g (100 mmol) biphenylboronic acid [5122-94-1], 21.2 g (200 mmol) sodium carbonate, 1.16 g (1 mmol) tetrakistriphenylphosphinopalladium(0), 150 ml toluene, 50 ml dioxane, and 100 ml water is heated under reflux for 16 minutes. After cooling, the precipitated solid is filtered off, washed three times with 100 ml of water and twice with 50 ml of methanol, and dried under vacuum. The solid is stirred hot in 150 ml of acetonitrile, filtered off, and dried under vacuum. Yield: 24.2 g (91 mmol), 91%. Purity: approx. 97% n. 1< H-NMR. Level S2b:

[0200]

[0201] A well-stirred mixture of 26.6 g (100 mmol) S2a, 15.6 g (100 mmol) 4-chlorophenylboronic acid [1679-18-1], 27.6 g (200 mmol) potassium carbonate, 702 mg (1 mmol) bis-triphenylphosphine palladium(II) chloride, 50 g glass beads (3 mmol diameter), 200 mL acetonitrile, and 100 mL methanol is heated under reflux for 16 h. After cooling, the precipitated solid is filtered off, washed three times with 100 mL water and twice with 50 mL methanol, and dried under vacuum. The solid is dissolved in 500 mL dichloromethane (DCM) and 100 mL ethyl acetate (EE) and filtered over a silica gel bed pre-flourished with DCM. The filtrate is concentrated under vacuum. The remaining solid is stirred with 150 ml of hot ethanol, filtered by suction, and dried under vacuum. Yield: 27.3 g (80 mmol), 80%; Purity: approx. 97%, < ¹H NMR. Level S2c:

[0202]

[0203] A mixture of 34.2 g (100 mmol) S₂b, 26.7 g (105 mmol) bis(pinacolato)diborane, 29.4 g (300 mmol) anhydrous potassium acetate, 50 g glass beads (3 mm diameter), and 500 ml THF is stirred with 821 mg (2 mmol) S-phosphate and then with 225 mg (1 mmol) palladium(II) acetate and heated under reflux for 16 h. While still hot, the salts and glass beads are filtered through a Celite bed pre-flourished with THF, the bed is washed with a little THF, and the filtrate is concentrated to dryness. The residue is dissolved in 100 ml MeOH, stirred while warm, filtered from the crystallized product, washed twice with 30 ml of methanol each time, and dried under vacuum. Yield: 36.4 g (84 mmol), 84%; Purity: approx. 95% n. 1< H-NMR. Level S2:

[0204] A well-stirred mixture of 21.3 g (100 mmol) S₂C, 13.6 g (100 mmol) 1-bromo-2-iodobenzene [583-55-1], 53.0 g (500 mmol) sodium carbonate, 400 ml toluene, 200 ml ethanol, and 400 ml water is treated with 1.57 g (6 mmol) triphenylphosphine and then with 449 mg (2 mmol) palladium(II) acetate and heated under reflux for 16 h. After cooling, the organic phase is separated, washed twice with 200 ml of water each time, once with 200 ml saturated saline solution, and dried over magnesium sulfate. The mixture is filtered through a Celite bed pre-flourished with toluene, the filtrate is concentrated to dryness, and the residue is recrystallized from approximately 50 ml of methanol with the addition of a small amount of ethyl acetate. Yield: 37.4 g (83 mmol), 83%; Purity: approximately 95%, < ¹H NMR.

[0205] The following connections can be represented analogously: Example. Starting materials product Yield* S3 54 % Stage a 654664-63-8 S4 47 % Stage a 395087-89-5 * over three levels Example S20:

[0206] Level S20b:

[0207]

[0208] A well-stirred mixture of 27.4 g (100 mmol) 2,5-dichloro-4-iodopyridine [796851-03-1], 19.8 g (100 mmol) biphenylboronic acid [5122-94-1], 27.6 g (200 mmol) potassium carbonate, 702 mg (1 mmol) bis-triphenylphosphine palladium(II) chloride, 50 g glass beads (3 mmol diameter), 150 mmol acetonitrile, and 150 mL methanol is heated under reflux for 16 h. After cooling, the reaction mixture is stirred into 1000 mL water. The precipitated solid is filtered off, washed three times with 100 mL of water and once with 50 mL of methanol, and dried under vacuum. Yield: 29.4 g (98 mmol), 98%. Purity: approx. 97% n. 1< H-NMR. StageS20a:

[0209]

[0210] Procedure analogous to 20a, except that 12.2 g (100 mmol) of phenylboronic acid [98-80-6] is used instead of biphenylboronic acid [5122-94-1]. The crude product is dissolved in 300 ml of DCM and 100 ml of EE and filtered through a silica gel bed. After concentration of the filtrate, the solid is stirred hot from 70 ml of acetonitrile. Yield: 27.3 g (80 mmol), 80%; Purity: approx. 97%, < ¹H NMR. Level S20:

[0211] A well-stirred mixture of 34.2 g (100 mmol) S20b, 17.2 g (110 mmol) 2-chlorophenylboronic acid [3900-89-8], 41.5 g (300 mmol) potassium carbonate, 600 ml THF, and 200 ml water is mixed with 1.64 g (4 mmol) S-Phos and 499 mg (2 mmol) palladium(II) acetate and stirred under gentle reflux for 16 h. After cooling, the organic phase is separated, washed twice with 200 ml of saturated sodium chloride solution each time, and concentrated to dryness. The residue is boiled in 100 ml ethanol for 4 h. After cooling, the solid is filtered off by filtration, washed with 50 ml ethanol, and dried. Further purification is carried out by recrystallization from approximately 200 ml ethyl acetate. Yield: 25.9 g (62 mmol), 62%; Purity: approx. 95% n. 1< H-NMR.

[0212] The following connections can be represented analogously: Example. Starting materials product Yield* S21 50 % 877993-09-4 Stage 20a S22 54 % 654664-63-8 Stage 20a S23 46 % 1383628-42-9 Stage 20a S24 48 % 364050-45-3 Stage 20a S25 50 % 395087-89-5 Stage 20a S26 52 % 845952-58-2 Stage 20a S27 44 % 313454-72-1 Level 20 S28 81 % See only level S20 display. KR 2018045695 S29 87 % 22960-25-4 Level 20 only S30 85 % 2222066-63-7 Level 20 only * over three levels Example S50:

[0213]

[0214] A mixture of 21.1 g (50 mmol) S1, 20.4 g (100 mol) 4,4,5,5-tetramethyl-2-phenyl-1,3,2-dioxaborolane [24388-23-6], 63.4 g (600 mmol) sodium carbonate, 400 mL toluene, 200 mL ethanol, and 400 mL water is stirred very well with 1.58 g (6 mmol) triphenylphosphine and then with 449 mg (2 mmol) palladium(II) acetate and heated under reflux for 48 h. After cooling, the organic phase is separated, washed once with 300 mL water and once with 300 mL saturated saline solution, and dried over magnesium sulfate. The filtrate is filtered off the drying agent and concentrated completely under vacuum. The residue was flash chromatographed (Torrent column analyzer by A. Semrau). Yield: 17.1 g (41 mmol), 82%; Purity: approx. 97% n. 1< H-NMR.

[0215] The following connections can be represented analogously: Example. Starting materials product Out of- prey S51 329214-79-1 73 % S52 1171891-42-1 70 % S53 2225172-53-0 75 % S54 1171891-07-8 77 % S55 685103-98-4 70 % S56 171364-85-5 67 % S57 20 % 2225172-53-0, 50 mmol 24388-23-6, 50 mmol Example S100:

[0216]

[0217] A well-stirred mixture of 31.4 g (200 mmol) bromobenzene [108-86-1], 16.1 g (100 mmol) 1-chloro-3,5-ethynylbenzene [1378482-52-0], 194.5 mL (1.5 mol) triethylamine, 700 mL DMF, and 2.31 g (2 mmol) tetrakistriphenylphosphinopalladium(0) is stirred for 16 h at 70 °C. While still warm, triethylammonium hydrobromide is filtered off and washed once with 50 mL DMF. The filtrate is concentrated to dryness, and the residue is dissolved in 1000 mL dichloromethane. The organic phase is washed three times with 300 mL of water and once with 300 mL saturated sodium chloride solution and dried over magnesium sulfate. The organic phase is concentrated to approximately 300 ml, mixed with 100 ml of ethyl acetate, filtered through a silica gel bed, and the solvent is removed under vacuum. The resulting solid is stirred once with 150 ml of methanol and then dried under vacuum. The solid is then dissolved in a mixture of 500 ml of THF and 100 ml of MeOH with the addition of 10.7 g (200 mmol) of ammonium chloride and 5 g of palladium (5%) were hydrogenated on carbon at 40 °C under a 2 bar hydrogen atmosphere until hydrogen uptake was complete (approx. 12 h). The mixture was filtered from the catalyst through a Celite bed pre-flourished with THF, the solvent was removed under vacuum, and the residue was flash-chromatographed on an automated column chromatograph (CombiFlashTorrent, A. Semrau).

[0218] Yield: 26.3 g (82 mmol), 82%; Purity: approx. 97% n. 1< H-NMR.

[0219] The following connections can be represented analogously: Example. Starting materials variant product yield S101 3972-64-3 78 % S102 626-55-1 80 % S103 4595-59-9 75 % S104 1209459-74-4 85 % S105 626-55-1 70 % Use of: MeOD / ND 4 Cl / D 2 Example S200:

[0220]

[0221] A mixture of 41.7 g (100 mmol) S50, 26.7 g (105 mmol) bis(pinacolato)diborane [73183-34-3], 29.4 g (300 mmol) potassium acetate (anhydrous), 50 g glass beads (3 mm diameter), and 300 ml THF is stirred with 821 mg (2 mmol) S-Phos and then with 225 mg (1 mmol) palladium(II) acetate and heated under reflux for 16 h. After cooling, the salts and glass beads are filtered off through a Celite bed pre-flourished with THF, the bed is washed with a little THF, and the filtrate is concentrated to dryness. The residue is dissolved in 100 ml of MeOH, stirred while warm, filtered off the crystallized product by suction, washed twice with 30 ml of methanol each time, and dried under vacuum. Yield: 45.8 g (90 mmol), 90%; Purity: approx. 95%, < ¹H NMR.

[0222] The following connections can be represented analogously: Example. Starting materials product yield S201 S51 88 % S202 S52 85 % S203 S53 87 % S204 S54 91 % S205 S55 90 % S206 S56 93 % S207 S57 90 % S300 S100 84 % S301 S101 81 % S302 S102 86 % S303 S103 77 % S304 S104 88 % S305 S105 80 % Example S400:

[0223]

[0224] A well-stirred mixture of 50.8 g (100 mmol) S200, 31.4 g (120 mmol) tri-isopropylsilyl ethynyl bromide [111409-79-1], 26.5 g (250 mmol) sodium carbonate, 2.31 g (2 mmol) tetrakis-triphenylphosphinopalladium(0), 600 ml toluene, 300 ml ethanol, and 100 ml water is stirred for 24 h at 80 °C. After cooling, the organic phase is separated, washed twice with 200 ml of saturated sodium chloride solution each time, and dried over magnesium sulfate. Filter off the drying agent, concentrate the filtrate under vacuum at 30 °C, dissolve the residue in 500 ml of dichloromethane, add 110 ml of TBAF (1 M in THF) [10549-76-5], stir for 1 h at room temperature, then wash twice with 300 ml of water and twice with 200 ml of saturated saline solution, concentrate at 30 °C, and chromatograph the residue on an automated column chromatograph (CombiFlashTorrent, A. Semrau). Store the product in a freezer. Yield: 29.4 g (72 mmol), 72%; Purity: approx. 97%, < ¹H NMR.

[0225] The following connections can be represented analogously: Example. Starting materials product yield S401 S201 68 % S402 S202 65 % S403 S203 71 % S500 S301 70 % S501 S302 67 % B: Synthesis of the ligands L: Example L1:

[0226]

[0227] A mixture of 50.9 g (100 mmol) S200, 31.0 g (100 mmol) 2-(2'-bromo-[1,1'-biphenyl]-4-yl)pyridine [1374202-35-3], 63.7 g (300 mmol) tripotassium phosphate, 400 ml toluene, 200 ml dioxane, and 400 ml water is stirred with 1.64 g (4 mmol) S-Phos and then with 449 mg (2 mmol) palladium(II) acetate and subsequently heated under reflux for 24 h. After cooling, the organic phase is separated, washed twice with 300 ml of water each time and once with 300 ml saturated saline solution, and dried over magnesium sulfate. The filtrate is filtered off the drying agent, concentrated under vacuum to dryness, and the glassy crude product is recrystallized at boiling temperature from acetonitrile (-150 ml) and then a second time from acetonitrile / ethyl acetate. Yield: 43.3 g (71 mmol), 71%; Purity: approx. 95%, < ¹H NMR.

[0228] The following connections can be represented analogously: Example. Starting materials variant product exploitation L2 S2 75 % S200 L3 S3 79 % S200 L4 S4 70 % S200 L5 73 % 1989597-29-6 S201 L6 1989597-32-1 70 % S201 L7 S20 77 % S201 L8 S21 72 % S202 L9 S22 67 % S203 L10 S26 69 % S204 L11 S29 76 % S205 L12 S30 75 % S206 L13 S20 65 % S207 L10 0 S24 67 % S300 L10 1 S3 78 & S301 L10 2 S21 74 % S302 L10 3 S25 70 % S303 L10 4 S23 69 % S304 L10 5 S27 72 % S304 L10 6 S28 75 % S304 L10 7 S21 72 % S305 Example L200:

[0229]

[0230] A well-stirred mixture of 23.4 g (100 mmol) 2-(4-bromophenyl)pyridine [63993-36-1], 40.7 g (100 mmol) S400, 81.5 g (250 mmol) cesium carbonate, 50 g glass beads (3 mm diameter), 787 mg (1 mmol) XPhos-Pd-G2 [1310584-14-5], 477 mg (1 mmol) XPhos [564483-18-7], and 500 ml acetonitrile is stirred for 16 h at 90 °C. The salts are filtered off while still warm and washed twice with 200 ml of DCM each time. The filtrate is concentrated to dryness. The residue is dissolved in 1000 ml of dichloromethane. The organic phase is washed three times with 300 ml of water each time and once with 300 ml of saturated sodium chloride solution and dried over magnesium sulfate. The organic phase is concentrated to approximately 500 ml, mixed with 200 ml of ethyl acetate, filtered over a silica gel bed, and the solvent is removed under vacuum. The resulting solid is stirred once with 150 ml of methanol and then dried under vacuum.The solid is hydrogenated in a mixture of 500 ml THF and 100 ml MeOH with the addition of 10.7 g (200 mmol) ammonium chloride and 5 g palladium (5%) on carbon at 40 °C under a 2 bar hydrogen atmosphere until hydrogen uptake is complete (approx. 12 h). The mixture is filtered from the catalyst through a Celite bed pre-flourished with THF, the solvent is removed under vacuum, and the residue is flash-chromatographed on an automated column chromatograph (CombiFlashTorrent, A. Semrau). Yield: 35.6 g (63 mmol), 63%; purity: approx. 97%, < 1H NMR.

[0231] The following connections can be represented analogously: Example. Starting materials product yield L201 S20b 55 % S201 L202 S22b 58 % S202 L203 S28 Educt 61 % S203 L300 S2b 57 % S501 L301 S21b 60 % S502 C: Synthesis of the complexes: C1: Neutral, monodentate co-ligands Example Ir100:

[0232]

[0233] A mixture of 6.12 g (10 mmol) L1, 4.15 g (10 mmol) [(1,2,5,6-η)-1,5-Cyclooctadiene][(1,2,3,3a,7a-η)-1 H[Inden-1-yl]-iridium (= (Ind)Ir(COD)) [102525-11-1], 100 ml glacial acetic acid, and 100 ml dioxane are stirred at 100 °C for 24 h. The red solution is concentrated to dryness, the residue is dissolved in 100 ml DCM, 5 ml triethylamine is added, and a stream of carbon monoxide is passed through the solution at 25 °C with good stirring for 3 h. The DCM is then distilled off, and the distilled DCM is continuously replaced with methanol. Finally, the solution is concentrated under vacuum to a volume of approximately 50 ml, the product is filtered off, washed three times with 30 ml of methanol each time, and dried under vacuum. Purification is carried out by two chromatographic reactions on silica gel with DCM / n-heptane (2:1, vv). The product obtained in this way can be further purified by hot extraction and annealing or fractional sublimation, as described in WO 2016 / 124304. Yield: 4.42 g (6.3 mmol); 63% of theory; purity: > 99.5% n.l. < ¹H NMR.

[0234] The following connections can be represented analogously: Example. Ligand product yield Ir101 L2 48 % Ir102 L3 45 % Ir103 L4 49 % 7188-38-7 25 mmol instead of CO Ir104 L100 37 % 931-54-4 25 mmol instead of CO Ir105 L101 55 % Ir106 L200 51 % PMe 3 504-09-2 25 mmol instead of CO Ir107 L300 37 % PF 3 7783-55-3 25 mmol instead of CO C2: Monoanionic, monodentate co-ligands Example IR200:

[0235]

[0236] A mixture of 6.14 g (10 mmol) L5 and 3.53 g (10 mmol) IrCl3 x 3 H2O [13569-57-8], 150 ml ethoxyethanol, and 50 ml water is heated under reflux for 24 h. The brown suspension is concentrated to dryness, the residue is dissolved in 50 ml DMSO, 1.08 g (22 mmol) sodium cyanide [143-33-9] is added, and the mixture is stirred for 8 h at 50 °C. After removal of the solvent under vacuum, the residue is dissolved in 200 ml DCM and chromatographed on silica gel. The yellow core fraction (Rf ~ 0.8) is removed, and the DCM is distilled off by rotary evaporation at 50 °C in a water bath at atmospheric pressure, with the distilled volume of DCM being continuously replaced by the addition of EtOH.

[0237] After completion of the DCM distillation, the solution is concentrated under vacuum to approximately 100 ml volume. The yellow solid is filtered through a reverse frit, washed twice with 50 ml of ethanol each time, and dried first under argon and then under vacuum (p ~ 10⁻³ mbar, T ~ 100 °C). The product thus obtained can be further purified by hot extraction and fractional sublimation, as described in WO 2016 / 124304. Yield: 4.06 g (4.7 mmol); 4.7% of theory; purity: > 99.5% by < ¹H NMR and HPLC.

[0238] The following connection can be represented analogously: Example. Ligand product yield Ir201 L7 43 % C3: Monoanionic and neutral, monodentate co-ligands Example IR300:

[0239]

[0240] Preparation analogous to C2. Use of 8.21 g (10 mmol) L13, 490 mg (10 mmol) NaCN and 1.03 g (10 mmol) phenyl-isonitrile [931-54-4].

[0241] Yield: 2.65 g (2.3 mmol); 23% of theory, diastereomeric mixture; Purity: > 99.0% n. 1< H-NMR. C4: Neutral, bidentate co-ligands Example IR400:

[0242]

[0243] A mixture of 7.64 g (10 mmol) L2, 4.15 g (10 mmol) [(1,2,5,6-η)-1,5-cyclooctadiene][(1,2,3,3a,7a-η)-1 H102525-11-1]-inden-1-yl-iridium (= (Ind)Ir(COD)) [102525-11-1], 100 ml glacial acetic acid, and 100 ml dioxane are stirred at 100 °C for 24 h. The red solution is concentrated to dryness, the residue is dissolved in 100 ml DCM, 5 ml triethylamine is added, followed by 1.87 g (12 mmol) of 2,2'-bipyridine [366-18-7], and the mixture is stirred for 12 h. The DCM is then distilled off, and the distilled-off DCM is continuously replaced with methanol. Finally, the mixture is concentrated under vacuum to a volume of approximately 50 ml, the product is filtered off, washed three times with 30 ml of methanol each time, and dried under vacuum. Purification is carried out by two chromatographic reactions on silica gel with DCM / EE (2:1, vv). The product obtained in this way can be further purified by hot extraction and annealing or fractional sublimation, as described in WO 2016 / 124304. Yield: 3.67 g (3.3 mmol); 33% of theory; Purity: > 99.5% n.l. < ¹H NMR. C5: Monoanionic, bidentate co-ligands Example IR500:

[0244]

[0245] A mixture of 8.21 g (10 mmol) L13 and 3.53 g (10 mmol) IrCl3 x 3 H2O [13569-57-8], 150 ml ethoxyethanol, and 50 ml water is heated under reflux for 24 h. The brown suspension is concentrated to dryness, the residue is dissolved in 100 ml 2-ethoxyethanol, 7.76 g (50 mmol) 2-phenylpyridine [1008-89-5] and then 7.71 g (30 mmol) silver trifluoromethanesulfonate [2923-28-6] are added, and the mixture is stirred for 16 h at 130 °C. The solvent is removed under vacuum, the residue is dissolved in 300 ml of DCM, filtered through a Celite bed pre-flourished with DCM, the DCM is distilled off, and it is continuously replaced with methanol. Finally, the solution is concentrated to approximately 100 ml, the precipitated product is filtered off, washed three times with 30 ml of methanol each time, and dried under vacuum. Purification is carried out by two chromatographic reactions on silica gel with toluene / DCM (9:1, vv). The product thus obtained can be processed by hot extraction and annealing, as described in WO 2016 / 124304.Further purification by fractional sublimation. Yield: Ir500a, diastereomer 1: 2.50 g (2.1 mmol); Ir500b, diastereomer 2: 2.24 g (1.9 mmol); Purity: > 99.5% n. 1< H-NMR. C6: Dianionic, bidentate co-ligands Example IR600:

[0246]

[0247] A 1000 ml three-necked flask with a magnetic stir bar, water separator with reflux condenser and argon atmosphere, internal thermometer (Pt-100 thermocouple), and dropping funnel is charged under an argon atmosphere with 6.14 g (10 mmol) of ligand L5, 3.53 g (10 mmol) of IrCl₃·3H₂O [13569-57-8], 29.45 g (300 mmol) of anhydrous potassium acetate [127-08-2], 244 g (2 mol) of benzoic acid [65-85-0], and 9.47 ml (100 mmol) of acetic anhydride [108-24-7]. The reaction mixture is rapidly heated to 250 °C and then stirred for 3 h at this temperature. The distilled acetic acid is removed via the water separator. After 3 hours, the reaction mixture is allowed to cool to 130 °C, and then 500 ml of methanol is added slowly, dropwise (caution: bumping is possible!). The precipitated product is allowed to settle, decanted from the supernatant, transferred to a reverse frit with methanol, filtered off, washed three times with 50 ml of hot methanol, and dried under vacuum.The solid is suspended in 300 ml of warm DCM for 1 h and then chromatographed with DCM on 300 g of silica gel 60 (Merck). The yellow-orange core fraction (Rf ~ 0.9) is removed, and the DCM is distilled off using a rotary evaporator at a water bath temperature of 50 °C and atmospheric pressure, with the distilled volume of DCM being continuously replaced by the addition of ethanol. After completion of the DCM distillation, the sample is concentrated under vacuum to approximately 100 ml, the yellow solid is filtered off using a reverse frit, washed twice with 50 ml of ethanol each time, and dried first under argon and then under vacuum (p ~ 10⁻³ < mbar, T ~ 100 °C). The product thus obtained can be further purified by hot extraction and fractional sublimation as described in WO 2016 / 124304. Yield: 8.5 g (9.00 mmol); 90% of theory; Purity: > 99.5% by < ¹H-NMR and HPLC.

[0248] The following connections can be represented analogously: Example. Ligand product yield Ir601 L6 67 % 98-73-3 Ir602 L7 70 % 67688-80-6 Ir603 L8 64 % 65898-38-6 Ir604 L9 34 % 126230-73-7 Ir605 L10 67 % 92-92-2 Ir606 L11 63 % 86-55-5 Ir607 L12 48 % 455-40-3 Ir608 L102 77 % 65-85-0 Ir609 L103 60 % 16317-22-9 Ir610 L104 38 % 140-10-3 Ir611 L105 55 % 7114-80-9 Ir612 L106 22 % 26537-68-8 Ir613 L201 69 % 1877288-45-3 Ir614 L202 55 % 13182-65-5 Ir615 L203 61 % 847955-90-2 Ir616 L301 67 % 98-73-3 Ir617 L7 70 % 65-85-0 Ir618 L107 77 % 65-85-0 Example: Manufacturing of OLEDs 1) Vacuum-processed devices:

[0249] The production of OLEDs according to the invention as well as OLEDs according to the prior art is carried out according to a general method according to WO 2004 / 058911, which is adapted to the conditions described here (layer thickness variation, materials used).

[0250] The following examples present the results for various OLEDs. Cleaned glass plates (cleaned in a Miele laboratory dishwasher using Merck Extran detergent) coated with 50 nm thick structured ITO (indium tin oxide) are pretreated with UV ozone for 25 minutes (UV ozone generator PR-100, UVP) and, within 30 minutes, coated with 20 nm PEDOT:PSS (poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate), sourced as CLEVIOS™< P VP Al 4083 from Heraeus Precious Metals GmbH Germany, centrifugally applied from aqueous solution) for improved processing. The coated plates are then baked out at 180 °C for 10 minutes. These coated glass plates form the substrates onto which the OLEDs are applied.

[0251] The OLEDs generally have the following layer structure: Substrate / Hole injection layer 1 (HIL1) consisting of HTM1 doped with 5% NDP-9 (commercially available from Novaled), 20 nm / Hole transport layer 1 (HTL1) consisting of HTM1, 150 nm for blue devices, 215 nm for green / yellow devices, 110 nm for red devices / Hole transport layer 2 (HTL2) / Emission layer (EML) / Hole blocking layer (HBL) / Electron transport layer (ETL) and finally a cathode. The cathode is formed by a 100 nm thick aluminum layer.

[0252] First, vacuum-processed OLEDs are described. For this process, all materials are thermally evaporated in a vacuum chamber. The emission layer always consists of at least one matrix material (host material) and an emitting dopant, which is added to the matrix material(s) by cobalt evaporation in a specific volume fraction. A specification such as M1:M2:Ir(L1) (55%:35%:10%) means that material M1 is present in the layer at a volume fraction of 55%, M2 at a volume fraction of 35%, and Ir(L1) at a volume fraction of 10%. Similarly, the electron transport layer can also consist of a mixture of two materials. The exact structure of the OLEDs can be found in Table 1. The materials used to fabricate the OLEDs are shown in Table 4.

[0253] The OLEDs are characterized according to standard procedures. This includes determining the electroluminescence spectra, current efficiency (measured in cd / A), power efficiency (measured in imp / W), and external quantum efficiency (EQE, measured in percent) as a function of luminance, calculated from current-voltage-luminance curves (IUL curves) assuming a Lambertian emission characteristic, as well as the lifetime. The electroluminescence spectra are determined at a luminance of < 1000 cd / m², and the CIE 1931 x and y color coordinates are calculated from them. The OLEDs can initially be operated at other starting luminances. The lifetime values ​​can then be converted to values ​​for other starting luminances using conversion formulas known to those skilled in the art. Use of compounds according to the invention as emitter materials in phosphorescent OLEDs

[0254] The compounds according to the invention can be used, among other things, as phosphorescent emitter materials in the emission layer of OLEDs. The results for the OLEDs are summarized in Table 2. Table 1: Structure of OLEDs Example. HTL2 thickness EML thickness HBL thickness ETL Thickness D1 HTM3 M3:M4:lr101 (30%:60%:10%) ETM1 ETM1:ETM2 (50%:50%) 20 nm 30 nm 10nm 30 nm D2 HTM2 M1:M2:lr201 (30%:60%:10%) ETM1 ETM1:ETM2 (50%:50%) 10 nm 30 nm 10nm 30 nm D3 HTM2 M1:M2:Ir500a (60%:30%:10%) ETM1 ETM1:ETM2 (50%:50%) 10 nm 30 nm 10nm 30 nm D4 HTM2 M1:M2:Ir608 (45%:45%:10%) ETM1 ETM1:ETM2 (50%:50%) 10 nm 30 nm 10nm 30 nm D5 HTM2 M1:M2:Ir617 (45%:45%:10%) ETM1 ETM1:ETM2 (50%:50%) 10 nm 30 nm 10nm 30 nm Table 2: Results of vacuum-processed OLEDs Example. EQE (%) 1000 cd / m²< Voltage (V) 1000 cd / m²< CIE x / y 1000 cd / m²< D1 23.2 3.6 0.16 / 0.35 D2 25.7 3.1 0.32 / 0.63 D3 23.8 3.0 0.51 / 0.48 D4 27.3 3.1 0.52 / 0.48 D5 27.9 3.0 0.56 / 0.43 Solution-processed devices: A: Made from low molecular weight soluble functional materials

[0255] The iridium complexes according to the invention can also be processed from solution, resulting in significantly simpler OLEDs compared to vacuum-processed OLEDs, while still exhibiting good properties. The fabrication of such components is based on the production of polymer light-emitting diodes (PLEDs), which has been extensively described in the literature (e.g., in WO 2004 / 037887). The structure consists of a substrate, an ITO layer, a hole injection layer (60 nm), an interlayer (20 nm), an emission layer (60 nm), a hole blocking layer (10 nm), an electron transport layer (40 nm), and a cathode. Substrates from Technoprint (sodalime glass) are used, onto which the ITO structure (indium tin oxide, a transparent, conductive anode) is deposited. The substrates are cleaned in the cleanroom with DI water and a detergent (Deconex 15 PF) and then activated by a UV / ozone plasma treatment.Subsequently, a 20 nm hole injection layer (PEDOT:PSS from Clevios™) is applied by spin coating, also in a cleanroom. The required spin rate depends on the dilution level and the specific spin coater geometry. To remove residual water from the layer, the substrates are baked out for 30 minutes at 200 °C on a hot plate. The interlayer used facilitates hole transport; in this case, HL-X from Merck is employed. Alternatively, the interlayer can be replaced by one or more layers, which only need to meet the requirement of not being removed by the subsequent processing step of EML deposition from solution. To produce the emission layer, the triplet emitters according to the invention are dissolved together with the matrix materials in toluene or chlorobenzene.The typical solids content of such solutions is between 16 and 25 g / L when, as in this case, the typical device layer thickness of 60 nm is to be achieved by spin coating. The solution-processed devices contain an emission layer of M5:M6:IrL (20%:55%:25%). The emission layer is spin-coated in an inert gas atmosphere, in this case argon, and baked out for 10 minutes at 160 °C. The hole-blocking layer (10 nm ETM1) and the electron transport layer (40 nm ETM1 (50%) / ETM2 (50%)) are then deposited (using Lesker e.g., deposition equipment, typical deposition pressure 5 x 10⁻⁶ < mbar). Finally, an aluminum cathode (100 nm) (high-purity metal from Aldrich) is deposited. To protect the device from air and humidity, it is encapsulated and then characterized. The OLED examples mentioned are not yet optimized. Table 3 summarizes the data obtained. Table 3: Results with materials processed from solution Example. Emitter Device EQE (%) Voltage (V) CIE x / y 1000 cd / m² 1000 cd / m² 1000 cd / m² Sol-D1 Ir107 20.0 4.6 0.28 / 0.60 Sol-D2 Ir300 19.3 4.5 0.48 / 0.51 Sol-D3 Ir400 16.2 4.7 0.56 / 0.41 Sol-D4 Ir602 21.8 4.5 0.56 / 0.43 Sol-D5 Ir606 20.7 4.4 0.66 / 0.34 Sol-D6 Ir613 19.8 4.6 0.47 / 0.49 Sol-D7 Ir616 21.5 4.4 0.49 / 0.50 Table 4: Structural formulas of the materials used HTM1 [136463-07-5] HTM2 [1450933-43-3] HTM3 [1206465-62-4] M1 [1257248-13-7] M2 [1357150-54-9] M3 [1201800-83-0] M4 [550378-78-4] M5 [1616231-60-7] M6 [1246496-85-4] ETM1 = M10 [1233200-52-6] ETM2 [25387-93-3]

Claims

1. A compound of the formula (1) wherein the symbols and indices used are as follows: L1 is a bidentate partial ligand which coordinates to the iridium via one carbon atom and one nitrogen atom or via two carbon atoms; L2, L3 are the same or different at each occurrence and are selected from an aryl or heteroaryl group having 5 to 14 aromatic ring atoms or a heteroalicyclic group having 5 to 7 ring atoms, each of which coordinates to the iridium via a carbon atom or a nitrogen atom each of which is part of the aryl or heteroaryl group or the heteroalicyclic group, and which may be substituted by one or more R radicals; L4 is a bidentate ligand or is the same or different at each occurrence and is a monodentate ligand; a is 1 when L4 is a bidentate ligand, and is 2 when L4 is a monodentate ligand; V is a group of the formula (2) or (3) wherein the dotted bonds each represent the position of linkage to the partial ligands L1, L2 and L3, and furthermore: A is the same or different at each occurrence and is CR2-CR2 or a group of the following formula (4): wherein the dotted bond in each case represents the position of the bond of the partial ligands L1, L2 or L3 and * represents the position of the linkage of the unit of the formula (4) to the central trivalent aryl or heteroaryl group in formula (2) or to the central cyclohexane group in formula (3); X1 is the same or different at each occurrence and is CR or N; X2 is the same or different at each occurrence and is CR or N; or two adjacent X2 groups together are NR, O or S, thus forming a five-membered ring, and the remaining X2 groups are the same or different at each occurrence and are CR or N; or two adjacent X2 groups together are CR or N when one of the X3 groups in the cycle is N, thus forming a five-membered ring, and the remaining X2 groups are the same or different at each occurrence and are CR or N; with the proviso that not more than two adjacent X2 groups in each ring are N; X3 is C at each occurrence in the same cycle or one X3 group is N and the other X3 group in the same cycle is C; with the proviso that two adjacent X2 groups together are CR or N when one of the X3 groups in the cycle is N; R is the same or different at each occurrence and is H, D, F, Cl, Br, I, N(R1)2, OR1, SR1, CN, NO2, COOH, C(=O)N(R1)2, Si(R1)3, Ge(R1)3, B(OR1)2, C(=O)R1, P(=O)(R1)2, S(=O)R1, S(=O)2R1, OSO2R1, a straight-chain alkyl group having 1 to 20 carbon atoms, or an alkenyl or alkynyl group having 2 to 20 carbon atoms, or a branched or cyclic alkyl group having 3 to 20 carbon atoms, wherein the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R1 radicals, and wherein one or more nonadjacent CH2 groups may be replaced by Si(R1)2, C=O, NR1, O, S or CONR1, or an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and which may each be substituted by one or more R1 radicals; optionally, two R radicals together may also form a ring system; R1 is the same or different at each occurrence and is H, D, F, Cl, Br, I, N(R2)2, OR2, SR2, CN, NO2, Si(R2)3, Ge(R2)3, B(OR2)2, C(=O)R2, P(=O)(R2)2, S(=O)R2, S(=O)2R2, OSO2R2, a straight-chain alkyl group having 1 to 20 carbon atoms, or an alkenyl or alkynyl group having 2 to 20 carbon atoms, or a branched or cyclic alkyl group having 3 to 20 carbon atoms, wherein the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R2 radicals, and wherein one or more nonadjacent CH2 groups may be replaced by Si(R2)2, C=O, NR2, O, S or CONR2, or an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and which may each be substituted by one or more R2 radicals; optionally, two or more R1 radicals together may also form a ring system; R2 is the same or different at each occurrence and is H, D, F, or an aliphatic, aromatic and / or heteroaromatic organic radical, in particular a hydrocarbyl radical, having 1 to 20 carbon atoms, in which one or more hydrogen atoms may also be replaced by F.

2. A compound as claimed in claim 1, characterized in that the group of the formula (2) is represented by formula (2a), and in that the group of the formula (3) is represented by formula (3a): wherein the symbols have the definitions given in claim 1.

3. A compound as claimed in claim 1 or 2, characterized in that the group of the formula (4) is represented by formula (4'): wherein the symbols have the definitions detailed in claim 1, and X2 is preferably the same or different at each occurrence and is CR.

4. A compound as claimed in one or more of claims 1 to 3, characterized in that all three A groups are the same group of the formula (4') with X2 = CR, or two A groups are the same group of the formula (4') with X2 = CR and the third A group is CR2-CR2, or one A group is a group of the formula (4') with X2 = CR and the two other A groups are the same CR2-CR2 group, or all three A groups are the same CR2-CR2 group.

5. A compound as claimed in one or more of claims 1 to 4, characterized in that the group of the formula (2) is selected from the groups of the formulae (2a-1) to (2d-1), and the group of the formula (3) is selected from the groups of the formulae (3a-1) to (3d-1): wherein the symbols have the definitions given in claim 1.

6. A compound as claimed in one or more of claims 1 to 5, characterized in that the partial ligand L1 has a structure of one of the following formulae (L1-1) and (L1-2): wherein the dotted bond represents the bond of the partial ligand L1 to V and the other symbols are as follows: CyC is the same or different at each occurrence and is a substituted or unsubstituted aryl or heteroaryl group which has 5 to 14 aromatic ring atoms and coordinates in each case to the iridium via a carbon atom ,and which is bonded to CyD via a covalent bond; CyD is the same or different at each occurrence and is a substituted or unsubstituted heteroaryl group which has 5 to 14 aromatic ring atoms or a substituted or unsubstituted heteroalicyclic group having 5 to 7 ring atoms, each of which coordinates to the iridium via a nitrogen atom or via a carbene carbon atom, and which is bonded to CyC via a covalent bond; wherein, optionally, two or more of the optional substituents together may form a ring system.

7. A compound as claimed in claim 6, characterized in that CyC is selected from the structures of the formulae (CyC-1) to (CyC-20), wherein the CyC group binds in each case at the position identified by # to CyD, and at the position identified by * to the iridium: and wherein CyD is selected from the structures of the formulae (CyD-1) to (CyD-23), wherein the CyD group binds in each case at the position identified by # to CyC and coordinates at the position identified by * to the iridium, wherein R has the definitions given in claim 1 and the other symbols used are as follows: X is the same or different at each occurrence and is CR or N, with the proviso that a maximum of two symbols X per ring are N; W is the same or different at each occurrence and is NR, O or S, and in CyD may additionally also be CR2; with the proviso that the symbol X bonded to the bridge V is C, where the bond to the bridge V is preferably via the position marked "o".

8. A compound as claimed in one or more of claims 1 to 7, characterized in that L1 is selected from the structures of the formulae (L1-1-1) to (L1-1-3) and (L1-2-1) to (L1-2-5) that coordinate to the iridium via the two positions identified by *: wherein the symbols have the definitions given in claims 1 and 7 and "o" represents the position of the bond to the bridge V, or L1 is selected from the structures of the formula (L1-39) or (L1-40) that coordinate to the iridium by the two positions identified by *: wherein "o" denotes the position of linkage to the bridge V, and in addition: X is the same or different at each occurrence and is CR or N; Z is CR', CR or N, with the proviso that exactly one Z is CR' and the other Z is CR or N; wherein a maximum of one symbol X or Z per cycle is N; R' is a group of the following formula (16) or (17): wherein the dotted bond indicates the linkage of the group to the partial ligands of the formula (L1-39) or (L1-40); R" is the same or different at each occurrence and is H, D, F, CN, a straight-chain alkyl group having 1 to 10 carbon atoms in which one or more hydrogen atoms may also be replaced by D or F, or a branched or cyclic alkyl group having 3 to 10 carbon atoms in which one or more hydrogen atoms may also be replaced by D or F, or an alkenyl group having 2 to 10 carbon atoms in which one or more hydrogen atoms may also be replaced by D or F; wherein, optionally, two adjacent R" radicals or two R" radicals on adjacent phenyl groups together may also form a ring system; or two R" on adjacent phenyl groups together are a group selected from C(R1)2, NR1, O or S, such that the two phenyl rings together with the bridging group are a carbazole, fluorene, dibenzofuran or dibenzothiophene, and the further R" are as defined above; n is 0, 1, 2, 3, 4 or 5.

9. A compound as claimed in one or more of claims 1 to 8, characterized in that L2 and L3 are the same or different at each occurrence and are selected from the structures of the formulae (L2-1) / (L3-1) to (L2-55) / (L3-55), wherein the groups each coordinate to the iridium at the position identified by * and to the bridgehead V at the position identified by "o": wherein R has the definitions given in claim 1 and the other symbols are as follows: X is the same or different at each occurrence and is CR or N, with the proviso that a maximum of two symbols X per ring are N; W is the same or different at each occurrence and is NR, O or S.

10. A compound as claimed in one or more of claims 1 to 9, characterized in that the monodentate ligands L4 are the same or different at each occurrence and are selected from the group consisting of carbon monoxide, nitrogen monoxide, alkyl cyanides, aryl cyanides, alkyl isocyanides, aryl isocyanides, amines, phosphines, phosphites, arsines, stibines, nitrogen heterocycles, carbenes, hydride, deuteride, fluoride, chloride, bromide, iodide, alkylacetylidene, arylacetylidene, cyanide, cyanate, isocyanate, thiocyanate, isothiocyanate, aliphatic or aromatic alkoxides, aliphatic or aromatic thioalkoxides, amides, carboxylates or aryl groups, and wherein the bidentate ligands L4 are selected from the group consisting of diamines, imines, diimines, heterocycles containing two nitrogen atoms, diphosphines, 1,3-diketonates derived from 1,3-diketones, 3-ketonates derived from 3-keto esters, carboxylates derived from aminocarboxylic acids, salicyliminates derived from salicylimines, dialkoxides derived from dialcohols, dithiolates derived from dithiols, bis(pyrazolylborates), bis(imidazolyl)borates, 3-(2-pyridyl)diazoles, or 3-(2-pyridyl)triazoles; or L4 is a ligand of one of the formulae (L4-1), (L4-2) and (L4-3): wherein the symbols used are as follows: CyC is the same or different at each occurrence and is a substituted or unsubstituted aryl or heteroaryl group which has 5 to 14 aromatic ring atoms and coordinates in each case to the metal via a carbon atom, and which is bonded to CyD via a covalent bond; CyD is the same or different at each occurrence and is a substituted or unsubstituted heteroaryl group which has 5 to 14 aromatic ring atoms and coordinates to the metal via a nitrogen atom or via a carbene carbon atom, and which is bonded to CyC via a covalent bond; wherein, optionally, two or more of the optional substituents together may form a ring system; or L4 is a ligand of one of the formulae (L4-19) to (L4-24), wherein these ligands each coordinate to the iridium via the two atoms identified by *: wherein R has the definitions given in claim 1 and X is the same or different at each occurrence and is CR or N, with the proviso that not more than two X are N.

11. A formulation comprising at least one compound as claimed in one or more of claims 1 to 10 and at least one further compound and / or a solvent.

12. The use of a compound as claimed in one or more of claims 1 to 10 in an electronic device, or as oxygen sensitizer, or as a photoinitiator, or as photocatalyst.

13. An electronic device comprising at least one compound as claimed in one or more of claims 1 to 10.

14. The electronic device as claimed in claim 13, which is an organic electroluminescent device, characterized in that the compound as claimed in one or more of claims 1 to 15 is used as emitter in an emitting layer in combination with one or more matrix materials selected from the group consisting of ketones, phosphine oxides, sulfur oxides, sulfones, triarylamines, carbazole derivatives, biscarbazoles, bridged carbazole derivatives, indolocarbazole derivatives, indenocarbazole derivatives, azacarbazoles, bipolar matrix materials, azaboroles, boronic esters, diazasilole derivatives, diazaphosphole derivatives, triazine derivatives, zinc complexes, dibenzofuran derivatives, dibenzothiophene derivatives or triphenylene derivatives.