METAL COMPLEX

Description

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

[0002] According to the state of the art, bis- and tris-orthometallated iridium complexes with aromatic ligands are primarily used as triplet transmitters 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.

[0003] In WO 2015 / 091716 A1 and WO 2016 / 193243 A1, OLEDs are disclosed which contain both a phosphorescent compound and a fluorescent emitter in the emission layer, whereby the energy is transferred from the phosphorescent compound to the fluorescent emitter (hyperphosphorescence). In this context, the phosphorescent compound behaves like a host material and itself exhibits no or at least no significant emission. In such a device structure, the phosphorescent compound is also referred to as a sensitizer.

[0004] Various emitter compounds for phosphorescent OLEDs are also described in US 9085579 B2, WO 2011053950 A1, WO 2012142387 A1, as well as in the articles by K. Dedeian et al., Inorg. Chem. 2007, 46(5):1603-11 and B. Anding et al., Organometallics 2014, 33(9):2219-2229.

[0005] The object of the present invention is to provide new and, in particular, improved metal complexes which are suitable as emitters for use in phosphorescent OLEDs or as sensitizers for use in hyperphosphorescent OLEDs and which exhibit good properties in the OLED, in particular good lifetime and efficiency.

[0006] Surprisingly, it was found that the metal complexes described below, which contain one tetradentate ligand and 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.

[0007] The invention relates to a compound of formula (1), Ir(L)(CN)(CN-R*) formula (1), wherein the symbols used are: R* is an alkyl group with 1 to 20 C atoms, which may be substituted by one or more R 1< groups, or an aromatic or heteroaromatic ring system with 5 to 30 aromatic ring atoms, which may be substituted by one or more R 1< groups; L is a tetradentate ligand of the following formula (2), wherein the tetradentate ligand is coordinated in a square-planar or approximately square-planar manner to the iridium and the cyano ligand (CN) and the isonitrile ligand (CN-R*) are arranged trans-in the (pseudo-)octahedral complex above and below the plane formed by the iridium and the tetradentate ligand; where * denotes coordination to iridium in each case, and for the other symbols and indices used: Y 1< , Y 2< , Y 3< , Y 4< is the same or different in each occurrence chosen from the group consisting of C, N or CO -< , with the proviso that at least one of the groups Y 1< , Y 2< , Y 3< and Y 4< stands for C and that two of the groups Y 1< , Y 2< , Y 3< and Y 4< coordinate to iridium via an anionic carbon atom, an anionic nitrogen atom or CO -< and the other two of the groups Y 1< , Y 2< , Y 3< and Y 4< coordinate to iridium via a neutral nitrogen atom or a carbene carbon atom;Ar 1< , Ar 2< , Ar 3< , Ar 4< is the same or different at each occurrence and together with the group Y 1< , Y 2< , Y 3< or Y 4< is an aryl group with 6 to 16 aromatic ring atoms or a heteroaryl group with 5 to 16 aromatic ring atoms or an aliphatic carbene with 5 to 10 ring atoms, wherein the aryl or heteroaryl group or the aliphatic carbene may each be substituted by one or more R groups; A1<, A2<, A3<, A4< is the same or different at each occurrence and is chosen from the group consisting of a single bond, CR2, BR, NR, O, S, CR2-CR2, CR=CR, an ortho-linked phenylene group which may be substituted with one or more R residues, C(=CR2) or -CR=N-; p is 0 or 1, where p = 0 means that the group A4< is not present and instead of A4< residues R may be bonded in the corresponding positions of Ar1< and Ar4<;R is the same or different in each occurrence 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 can also form a mono- or polycyclic, aliphatic, heteroaliphatic, aromatic or heteroaromatic 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;Two or more residues R1< can form a mono- or polycyclic, aliphatic, heteroaliphatic, aromatic, or heteroaromatic ring system; R2< 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.

[0008] The binding of A1< and, if present, A4< to Ar1< occurs in the ortho position to Y1<. The binding of A1< and A2< to Ar2< occurs in the ortho position to Y2<. The binding of A2< and A3< to Ar3< occurs in the ortho position to Y3<. The binding of A3< and, if present, A4< to Ar4< occurs in the ortho position to Y4<.

[0009] The compound according to the invention is a complex comprising a tetradentate ligand coordinated to the iridium in a square-planar or approximately square-planar manner, a monodentate cyano ligand, and a monodentate isonitrile ligand, wherein the cyano ligand and the isonitrile ligand are arranged trans-wise above and below the plane formed by the iridium and the tetradentate ligand in the (pseudo)octahedral complex. The geometry of the complex is shown schematically below:

[0010] During the deposition of the complex, the isonitrile ligand generally points towards the vacuum, while the cyano ligand aligns itself on the already deposited layer, such that the iridium and the tetradentate ligand lie approximately in the plane of the layer. This preferred orientation is a statistical distribution. Several advantages arise from this orientation: Firstly, the transition dipole moment, which lies in the plane of the tetradentate ligand and the iridium, is to a significant extent parallel, or at least approximately parallel, to the layer. Since the emission occurs perpendicular to the transition dipole moment, the emission is perpendicular to the layer plane (oriented emission), which in turn improves the extraction and thus the efficiency.Furthermore, the complex exhibits a significant permanent dipole moment, which, due to the complex's arrangement in the layer with the cyano ligand oriented towards the anode, leads to simplified hole and electron injection into the emission layer. This results in a reduction of the operating and break-in voltages, consequently improving the lifetime.

[0011] The binding of the ligands or coordinating groups to the iridium can be coordination bonds or covalent bonds, and the covalent component of the binding can vary depending on the ligand. When the present application refers to a ligand or group coordinating or binding to the iridium, this means, within the meaning of the present application, any type of binding of the ligands or group to the iridium, regardless of the covalent component of the binding.

[0012] When two R or R< substituents form a ring system, these substituents can be adjacent, meaning they are bonded to the same carbon atom or to carbon atoms that are directly bonded to each other, or they can be further apart. For example, ring formation is also possible between a R substituent at A< and a R substituent at Ar< and / or Ar<, or between a R substituent at A< and a R substituent at Ar< and / or Ar<, or between a R substituent at A< and a R substituent at Ar< and / or Ar<, or between a R substituent at A< and a R substituent at Ar< and / or Ar<, or between a R substituent at A<, if present, and a R substituent at Ar< and / or Ar<. Such ring formation is described in more detail below.

[0013] 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:

[0014] The formation of a condensed aromatic or heteroaromatic group is also possible, as illustrated by the following scheme:

[0015] 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:

[0016] 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.

[0017] 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 N,O and / or S. 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.,

[0022] The compounds according to the invention are electrically neutral. Charge neutrality is achieved by the charges of the coordinating groups balancing the charge of the triply positively charged iridium.

[0023] The cyano ligand contributes a negative charge, while the isonitrile ligand is neutral. Examples of suitable combinations of the coordinating groups Ar1<, Ar2<, Ar3<, and Ar4< within the ligand L are listed in the following table, with variants 1 and 2 being preferred: variant Ar 1< Ar 2< Ar 3< Ar 4< 1 neutral anionic anionic neutral 2 anionic neutral neutral anionic 3 anionic anionic neutral neutral 4 anionic neutral anionic neutral

[0024] Preferred embodiments of the tetradentate ligand L are described below.

[0025] For the coordinating atoms Y1< to Y4<, as described above, two of the groups Y1<, Y2<, Y3<, and Y4< coordinate to the iridium via an anionic carbon atom, an anionic nitrogen atom, or CO⁻<, and the other two of the groups Y1<, Y2<, Y3<, and Y4< coordinate to the iridium via a neutral nitrogen atom or a carbene carbon atom. Preferably, no more than one of the groups Y1< to Y4< represents CO⁻<. If a coordinating group represents CO⁻<, it is preferably Y1< or Y4<. Preferred combinations of Y1< to Y4< are listed in the following table: Y 1< Y 2< Y 3< Y 4< C (anionic) N (neutral) N (neutral) C (anionic) N (neutral) C (anionic) C (anionic) N (neutral) N (neutral) C (anionic) C (anionic) C (Carbene) C (Carbene) C (anionic) C (anionic) C (Carbene) N (neutral) C (anionic) N (neutral) C (anionic) N (neutral) C (anionic) N (neutral) CO -< C (anionic) N (neutral) N (neutral) CO -< N (neutral) N (neutral) C (anionic) CO -<

[0026] The groups Ar 1< to Ar 4< are described below. In a preferred embodiment of the invention, Ar 1<, Ar 2<, Ar 3< and Ar 4< together with the group Y 1<, Y 2<, Y 3< and Y 4< respectively, are, in each occurrence, either an aryl group with 6 to 14 aromatic ring atoms or a heteroaryl group with 5 to 14 aromatic ring atoms, wherein the aryl or heteroaryl group may each be substituted by one or more R groups. Particularly preferred are Ar 1< , Ar 2< , Ar 3< and Ar 4< together with the group Y 1< , Y 2< , Y 3< or Y 4< comprising, in each occurrence, an aryl group with 6 to 10 aromatic ring atoms, in particular with 6 aromatic ring atoms, or a heteroaryl group with 5 to 13 aromatic ring atoms, in particular with 5 to 10 aromatic ring atoms, wherein the aryl or heteroaryl group may each be substituted by one or more R groups.

[0027] In a preferred embodiment of the invention, the groups Ar 1< and Ar 4< together with the groups Y 1< and Y 4< respectively are selected from the groups of the following formulas (Ar-1) to (Ar-44), wherein the group binds to A 1< and A 3< respectively 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;

[0028] The groups (Ar-1) to (Ar-20) coordinate via an anionic carbon atom, the groups (Ar-21) to (Ar-24) and (Ar-29) to (Ar-40) via a neutral nitrogen atom, the groups (Ar-25) to (Ar-28) via a carbene carbon atom, the groups (Ar-41) to (Ar-43) via an anionic nitrogen atom to the iridium and the group (Ar-44) via an anionic oxygen atom.

[0029] If p = 1, i.e., the group A 4< is present, the binding of Ar 1< or Ar 4< to A 4< occurs via the ortho position for coordination to the iridium atom, so that in this position the group A 4< is then bound instead of a residue R.

[0030] Preferably, at most one symbol X in (Ar-1) to (Ar-44) represents N, and most preferably, all symbols X represent CR.

[0031] Preferred embodiments of groups (Ar-1) to (Ar-44) are the groups of the following formulas (Ar-1a) to (Ar-44a), 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.

[0032] In a preferred embodiment of the invention, the groups Ar 2< and Ar 3< together with the groups Y 2< and Y 3< respectively are selected from the groups of the following formulas (Ar-45) to (Ar-75), wherein the group binds to A 1< and A 2< and A 2< and A 3< respectively at the position marked by # and coordinates to the iridium at the position marked by *. where R, X and W have the meanings mentioned above.

[0033] In this process, the groups (Ar-45) to (Ar-59) coordinate to the iridium via an anionic carbon atom, the groups (Ar-60) to (Ar-62) and (Ar-66) to (Ar-72) via a neutral nitrogen atom, the groups (Ar-63) to (Ar-65) via a carbene carbon atom and the groups (Ar-73) and (Ar-74) via an anionic nitrogen atom.

[0034] Preferably, at most one symbol X in (Ar-45) to (Ar-74) represents N, and most preferably all symbols X represent CR.

[0035] Preferred embodiments of groups (Ar-45) to (Ar-74) are the groups of the following formulas (Ar-45a) to (Ar-74a), 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.

[0036] If A< represents a single bond, then in the partial ligand Ar<1< -Ar<2< two aryl or heteroaryl groups are directly bonded to each other, and if A<3< represents a single bond, then in the partial ligand Ar<3< -Ar<4< two aryl or heteroaryl groups are directly bonded to each other. If several of the substituents R in these units form a ring system together, then the formation of a ring system from substituents bonded to Ar<1< and Ar<2< or to Ar<3< and Ar<4< is also possible, whereby Ar<1< and Ar<2< or Ar<3< and Ar<4< can form a single fused aryl or heteroaryl group, respectively, as the bidentate partial ligand Ar<1< -Ar<2< or Ar<3< -Ar<4<, respectively, via the substituents R).

[0037] If A 1< or A 3< represent a single bond, the bidentate subligands Ar 1< -Ar 2< or Ar 3< -Ar 4< thus formed are preferentially selected from the structures of the following formulas (L 1< -1-1) to (L 1< -1-3) and (L 1< -2-1) to (L 1< -2-5), which coordinate to the iridium via the two positions marked with *. where the symbols used have the meanings mentioned above and # represents the position of the binding to A 2<.

[0038] 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 # represents the position of the bond to A 2<. 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 R.

[0039] If two remains R, When one of the substituents is bonded to Ar 1< and the other to Ar 2<, or one of the substituents is bonded to Ar 3< and the other to Ar 4<, forming an aromatic or heteroaromatic ring system, bridged partial ligands and partial ligands that together constitute a single larger heteroaryl group can result. This ring formation between the substituents preferably occurs through a group according to one of the following formulas (3) to (12). where R 1< has the meanings mentioned above, and the dashed bonds indicate bonds to Ar 1< and Ar 2< or to Ar 3< and Ar 4<, respectively. The asymmetrical elements of the groups mentioned above can be incorporated in either of these two possibilities.

[0040] The group of formula (9) 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).

[0041] Preferred ligands formed by ring formation of two residues R at Ar 1< and Ar 2< or at Ar 3< and Ar 4< are the structures listed below with formulas (L 1< -3) to (L 1< -28), where the symbols used have the meanings mentioned above and # indicates the position where this subligand is linked to A 2<.

[0042] In a preferred embodiment of the partial ligands of formulas (L 1< -3) to (L 1< -28) all symbols X stand for CR, or one symbol X stands for N and the other symbols X stand for CR.

[0043] In a further embodiment of the invention, it is preferred that, in groups (Ar-1) to (Ar-73) or in the partial ligands (L 1< -1) to (L 1< -28), 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 listed above, 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 C atoms, in particular branched or cyclic alkyl groups with 3 to 10 C atoms, OR1<, where R1< represents an alkyl group with 1 to 10 C atoms, in particular a branched or cyclic alkyl group with 3 to 10 C atoms, a dialkylamino group with 2 to 10 C atoms, aromatic orheteroaromatic ring systems or aralkyl or heteroaralkyl groups. These groups are sterically demanding. Furthermore, this residue R can preferably also form a cycle with a neighboring residue R.

[0044] In a preferred embodiment of the invention, two of the groups A1<, A2< and A3< each represent a single bond, and the third group represents a group other than a single bond. Preferred embodiments of the ligand L, in which two of the groups A1<, A2< and A3< represent a single bond, are the following ligands (L-1) and (L-2), where the symbols used have the meanings mentioned above, Y 1< to Y 4< stand for C or N, whether the same or different, and A 2< in formula (L-1) or A 3< in formula (L-2) do not stand for a single bond.

[0045] In this case, A 2< in formula (L-1) or A 3< in formula (L-2) preferably represents CR 2 , BR, NR, O or S, and the groups Ar 1< , Ar 2< , Ar 3< and Ar 4< each coordinate to the iridium via a six-membered ring and a carbon or nitrogen atom, or one of the groups Ar 1< or Ar 4< coordinates to the iridium via a five-membered ring and a carbon or nitrogen atom and the other members of the groups Ar 1< , Ar 2< , Ar 3< and Ar 4< each coordinate to the iridium via a six-membered ring and a carbon or nitrogen atom.

[0046] Alternatively, A 2< in formula (L-1) or A 3< in formula (L-2) preferably represents CR 2 -CR 2 , CR=CR or an ortho-phenylene group which may be substituted by one or more R groups, and at least one or preferably at least two of the groups Ar 1< , Ar 2< , Ar 3< and / or Ar 4< each coordinate to the iridium via a five-membered ring.

[0047] In a further preferred embodiment of the invention, one of the groups A1<, A2<, and A3< represents a single bond, and the other two groups represent, either identically or differently, a group other than a single bond. Preferred embodiments of the ligand L, in which exactly one of the groups A1<, A2<, and A3< represents a single bond, are the following ligands (L-3) and (L-4), where the symbols used have the meanings mentioned above and A 1< and A 3< in formula (L-3) and A 2< and A 3< in formula (L-4) do not represent single bonds.

[0048] In a preferred embodiment, A 1< and A 3< in formula (L-3) and A 2< and A 3< in formula (L-4) represent CR 2 , BR, NR, O or S, either the same or different, particularly preferably CR 2 , NR or O and most preferably O.

[0049] In a further preferred embodiment of the invention, exactly one of the groups Y' or Y4< represents CO-<. In this case, preferably either all three groups A1<, A2< and A3< represent a single bond, or A1< and A3< represent a single bond. These ligands are thus preferably the ligands of the following formulas (L-5) and (L-6), wherein the symbols used have the meanings mentioned above and A 2< in formula (L-6) stands for C=CR 2, wherein at least one residue R forms an aromatic or heteroaromatic ring system with Ar 2< or Ar 3<, or stands for CR 2 , NR or O, particularly preferably for O.

[0050] In yet another preferred embodiment of the invention, none of the groups A 1< , A 2< and A 3< represents a single bond, so that the ligand (L-7) preferably results, where the symbols used have the meanings mentioned above and A 1< , A 2< and A 3< do not stand for single bonds.

[0051] The ligands L are preferably chosen from the structures (L-1), (L-4), (L-6) and (L-7).

[0052] Preferred embodiments of the ligand (L-1) are the ligands of the following formulas (L-1-1) to (L-1-4), where X and A 2< have the meanings mentioned above and either E stands for N and the groups Y in the same cycle are the same or different at each occurrence representing CR or N, or E stands for C and the groups Y in the same cycle are the same or different at each occurrence representing CR, N, NR, O, or S, with the proviso that exactly one group Y stands for NR, O, or S, preferably for NR, and the other groups Y are the same or different at each occurrence representing CR or N. In formulas (L-1-1) and (L-1-2), A 2< preferably represents CR 2, BR, NR, O, or S, and particularly preferably CR 2, NR, or O. Furthermore, in formulas (L-1-3) and (L-1-4), A 2< preferably represents CR 2-CR 2, CR=CR, or an ortho-phenylene group, and particularly preferably CR 2-CR 2.

[0053] Ligands (L-1-1a) to (L-1-4c) are particularly favored. the symbols used have the meanings mentioned above.

[0054] Preferred embodiments of the ligands (L-4) are the ligands (L-4-1) to (L-4-3), where the symbols used have the meanings mentioned above and A 2< does not represent a single bond. Preferably, A 2< represents CR 2 , BR, NR, O or S. More preferably, in formula (L-4-3), the residue R on the nitrogen atom represents an aromatic or heteroaromatic ring system with 6 to 13 aromatic ring atoms, preferably with 6 to 12 aromatic ring atoms, each of which may be substituted with one or more residues R 1<.

[0055] Particularly preferred embodiments of ligand (L-4) are ligands (L-4-1a) to (L-4-3a), wherein the symbols have the meanings mentioned above and A 2< does not represent a single bond and preferably represents CR 2 , BR, NR, O or S. Furthermore preferably in formula (L-4-3a) the residue R on the nitrogen atom represents an aromatic or heteroaromatic ring system with 6 to 13 aromatic ring atoms, preferably with 6 to 12 aromatic ring atoms, each of which may be substituted with one or more residues R 1<.

[0056] If A 2< in formula (L-4) or in preferred embodiments represents NR, it is also possible and preferred that the residue R represents an aryl group, for example a phenyl group, and that this forms a ring with the adjacent coordinating group Ar 3<, for example a carbazole, a phenazine, or a phenoxazine. This results, for example, in the following ligands (L-4-2c), (L-4-2d), (L-4-2e), and (L-4-2f), respectively. where the symbols used have the meanings mentioned above and Q stands for a single bond, C(R 1< ) 2 , NR 2< or O, in particular for a single bond.

[0057] In a preferred embodiment of the ligand (L-6), A 2< represents C=CR 2 and one of the substituents R forms an aromatic ring system with the adjacent group Ar 2<, preferably forming a ligand of the following formula (L-6-1) or (L-6-2), where the symbols used have the meanings mentioned above and W preferably stands for NR.

[0058] A preferred embodiment of the ligand (L-6-1) is the ligand of the following formula (L-6-1a), and preferred embodiments of the ligand (L-6-2) are the ligands of the following formulas (L-6-2a) to (L-6-2c), the symbols used have the meanings mentioned above.

[0059] Preferred embodiments of the ligand (L-7) are the ligands of the following formula (L-7-1), where the symbols used have the meanings mentioned above and A 2< does not stand for a single bond.

[0060] A preferred embodiment of the ligands (L-7-1) are the ligands of the following formula (L-7-1a), where the symbols used have the meanings mentioned above and A 2< does not represent a single bond. Preferably, A represents O, NR or CR 2, in particular O.

[0061] The following describes preferred substituents as they can be found at Ar 1< , Ar 2< , Ar 3< and Ar 4< , but also at A 1< , A 2< , A 3< and, if present, A 4< .

[0062] In one embodiment of the invention, the metal complex according to the invention contains 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 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 (13) to (19), 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, R3 can form an aliphatic ring system with a neighboring residue R or R1.

[0063] 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 (13) to (19) 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 (16) to (19) 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 (16) to (19), 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.

[0064] Preferred embodiments of the groups of formulas (13) to (19) can be found in applications WO 2014 / 023377, WO 2015 / 104045 and WO 2015 / 117718.

[0065] Further preferred residues R are selected, in each occurrence the same or differently, 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 1< , 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.

[0066] Preferred substituents R1 bonded to R are, in each occurrence, the same or different: H, D, F, N(R2)2, CN, a straight-chain alkyl group with 1 to 10 carbon atoms, an alkenyl group with 2 to 10 carbon atoms, or a branched or cyclic alkyl group with 3 to 10 carbon atoms, wherein the alkyl group may be substituted by one or more substituents R2, or an aromatic or heteroaromatic ring system with 5 to 24 aromatic ring atoms, each of which may be substituted by one or more substituents R2; in this case, two or more adjacent substituents R1 may form a mono- or polycyclic aliphatic ring system. Particularly preferred substituents R1 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 R 2< groups, or an aromatic or heteroaromatic ring system with 5 to 13 aromatic ring atoms, each of which may be substituted by one or more R 2< groups; in this case, two or more adjacent R 1< groups may form a mono- or polycyclic aliphatic ring system.

[0067] Preferred substituents R 2< are, in each occurrence, the same or different 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.

[0068] Examples of suitable tetradentate ligands of formula (2) that can be used in the compounds according to the invention are the compounds shown below.

[0069] The isonitrile ligand C=NR* is described in more detail below. As described above, R* represents an alkyl group with 1 to 20 carbon atoms, which may also be substituted by one or more R1< groups, or an aromatic or heteroaromatic ring system with 5 to 30 aromatic ring atoms, which may be substituted by one or more R1< groups. The alkyl group can be linear, branched, or cyclic.

[0070] In a preferred embodiment, R* represents an alkyl group with 4 to 10 carbon atoms, in which one or more hydrogen atoms may also be replaced by D or F, or an aromatic ring system with 6 to 12 carbon atoms, preferably a phenyl group, wherein the aromatic ring system or the phenyl group may be substituted by one or more residues selected from F, D or an alkyl group with 1 to 10 carbon atoms, wherein the alkyl group may be linear, branched or cyclic and wherein one or more hydrogen atoms in the alkyl group may be replaced by D or F; several alkyl groups present as substituents on the aromatic ring system may also form a ring system together.

[0071] As described, R*, when it represents an alkyl group, can be linear, branched, or cyclic. Branched and cyclic alkyl groups are preferred, with cyclic alkyl groups being monocyclic, bicyclic, or oligocyclic and also potentially containing other alkyl groups, such as a methyl-substituted cyclohexyl group. Particularly preferred is R* a linear alkyl group with 4 to 8 carbon atoms, a branched alkyl group with 4 to 8 carbon atoms, a cyclopentyl or cyclohexyl group, each of which may be substituted with one or two methyl groups, or a bicyclic or oligocyclic alkyl group with 7 to 10 carbon atoms, such as bicyclo[2.2.1]heptane, bicyclo[2.2.2]octane, or adamantyl, wherein one or more hydrogen atoms in the alkyl group may be replaced by diol or fluorine.

[0072] Examples of suitable isonitrile ligands C=NR*, where R* represents an alkyl group, are the structures listed below:

[0073] Particularly preferred embodiments for R*, where R* represents an aromatic ring system, are a group of the following formula (20), where the dashed line indicates the linkage with the isonitrile group and R' is the same or different for H,F or an alkyl group with 1 to 10 carbon atoms, whereby adjacent alkyl groups can also form a ring system with each other. Preferably, a maximum of two groups R' are not equal to H. If the substituents R' represent an alkyl group, then this alkyl group can be linear, branched, or cyclic, whereby cyclic alkyl groups can be monocyclic, bicyclic, or oligocyclic and can also have further alkyl groups, such as a methyl-substituted cyclohexyl group. Particularly preferred, when R' represents an alkyl group, is a linear alkyl group with 1 to 6 C atoms or a branched alkyl group with 3 to 6 C atoms, a cyclopentyl or cyclohexyl group, each of which may be substituted with one or two methyl groups, or a bi- or oligocyclic alkyl group with 7 to 10 C atoms, such as bicyclo[2.2.1]heptane, bicyclo[2.2.2]octane or adamantyl, wherein two adjacent alkyl groups can also form a ring system with each other. If the group of formula (20) has only one substituent R' that is not equal to H and represents an alkyl group, then this is particularly preferentially bonded in the para position to link the isonitrile group.

[0074] Examples of suitable isonitrile ligands C=NR*, in which R* represents an optionally substituted phenyl group, are the structures listed below:

[0075] The preferred embodiments mentioned above can be combined with one another as desired. In a particularly preferred embodiment of the invention, the preferred embodiments mentioned above apply simultaneously.

[0076] 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 (step 1), whereby, in addition to a solvent, an auxiliary base, e.g., 2,6-dimethylpyridine, may also be present. The coordinating carbon monoxide can originate from the thermal decomposition of the solvent (e.g., ethylene glycol, DMF) or be added to the reaction mixture. The intermediate thus obtained (chlorocarbonyl complex) is then subjected to a successive exchange of the monodentate ligands, according to the Ir-ligand bond strength (steps 2 and 3). This is illustrated below using the example of a simple tetradentate ligand. Step 1:

[0077] Step 2: Exchange of chloride Cl-< for cyanide CN-<

[0078] Step 3: Replacement of carbon monoxide (CO) with iso-nitrile (R-NC)

[0079]

[0080] 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 (21), with iridium ketoketonates of formula (22), with iridium halides of formula (23), with iridium carboxylates of formula (24), iridium olefin cyclopentadienyl complexes of formula (25) or with iridium olefin indenyl complexes of formula (26), 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, or further weakly coordinating ligands, such as tetrahydrothiophene (THP), can be coordinated to the iridium halide. R preferably represents an alkyl group with 1 to 4 carbon atoms. Olefin in formulas (25) and (26) represents a diolefin, typically 1,5-cyclooctadiene, but also other diolefins such as cyclohexadiene or norbornadiene.

[0081] 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.

[0082] The synthesis of the complexes can be activated thermally, photochemically, and / or by microwave radiation. Furthermore, the synthesis can also be carried out in an autoclave under elevated pressure and / or temperature.

[0083] 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.

[0084] Furthermore, the synthesis can preferably be carried out in anhydrous medium in the presence of a carboxylic acid, as described in WO 2021 / 013775, 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 (21) to (26). 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.

[0085] Depending on the structure of the ligands, chiral compounds can also be formed. The invention covers both the individual enantiomers and diastereomers, as well as the racemates.

[0086] 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).

[0087] 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 (13) to (19) 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.

[0088] 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 are, for example, toluene, anisole, o-, m-, or p-xylene, methyl benzoate, mesitylene, tetralin, and veratrol. THF, Methyl-THF, THP,Chlorbenzol, Dioxan, Phenoxytoluol, insbesondere 3-Phenoxytoluol, (-)-Fenchon, 1,2,3,5-Tetramethylbenzol, 1,2,4,5-Tetramethylbenzol, 1-Methylnaphthalin, 2-Methylbenzothiazol, 2-Phenoxyethanol, 2-Pyrrolidinon, 3-Methylanisol, 4-Methylanisol, 3,4-Dimethylanisol, 3,5-Dimethylanisol, Acetophenon, α-Terpineol, Benzothiazol, Butylbenzoat, Cumol, Cyclohexanol, Cyclohexanon, Cyclohexylbenzol, Decalin, Dodecylbenzol, Ethylbenzoat, Indan, NMP, p-Cymol, Phenetol, 1,4-Diisopropylbenzol, Dibenzylether, Diethylenglycolbutylmethylether, Triethylenglycolbutylmethylether, Diethylenglycoldibutylether, Triethylenglycoldimethylether, Diethylenglycolmonobutylether, Tripropylenglycoldimethylether, Tetraethylenglycoldimethylether, 2-Isopropylnaphthalin, Pentylbenzol, Hexylbenzol, Heptylbenzol, Octylbenzol, 1,1-Bis(3,4-dimethylphenyl)ethan, Hexamethylindan, 2-Methylbiphenyl, 3-Methylbiphenyl, 1-Methylnaphthalin, 1-Ethylnaphthalin, Ethyloctanoat, Sebacinsäure-diethylester, Octyloctanoat, Heptylbenzol,Menthyl isovalerate, cyclohexylhexanoate or mixtures of these solvents.

[0089] 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 and / or another emitter, which can be fluorescent or phosphorescent.

[0090] The compound according to the invention can be used in an electronic device as an active component, preferably as an emitter in the emissive layer, as a sensitizer in the emissive layer, or as a hole or electron transport material in a hole- or electron-transporting layer, or as an oxygen sensitizer, photoinitiator, or photocatalyst. A further object of the present invention is therefore the use of a compound according to the invention in an electronic device, or as an oxygen sensitizer, photoinitiator, or photocatalyst.

[0091] A sensitizer within the meaning of the present invention is a compound which, by electrical excitation in the OLED, collects the singlet and triplet excitons and then transfers them non-radiatively, usually by a Förster transfer, to a fluorescent emitter as an acceptor, which relaxes to the ground state by emitting light.

[0092] Another object of the present invention is an electronic device comprising at least one connection according to the invention.

[0093] 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. Therefore, organic electroluminescent devices are a preferred embodiment of the invention.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] InIn a preferred embodiment of the invention, the organic electroluminescent device contains the iridium complex according to the invention in one or more emitting layers. Various applications are possible, in particular as a sensitizer for a fluorescent emitter or as a phosphorescent emitter.

[0098] When the compound according to the invention is used as a sensitizer in an emitting layer in combination with a fluorescent emitter in a hyperphosphorescent OLED, the OLED contains a fluorescent emitter in addition to the iridium complex. It is necessary that the photoluminescence spectrum of the sensitizer overlaps with the absorption spectrum of the fluorescent emitter. Furthermore, one or more host materials (matrix materials) are typically used.

[0099] In a preferred embodiment of the invention, when producing the emitting layer by vapor deposition, the compound according to the invention is present in the emitting layer in a concentration of 1 to 50 vol.%, preferably 2 to 40 vol.%, particularly preferably 3 to 30 vol.%, and most preferably 4 to 25 vol.%, wherein the specified volume % (vol.%) refer to the total volume of the emitting layer.

[0100] If the OLED is manufactured from solution, the corresponding proportions are preferred as described above, in which case they are expressed in wt.% instead of vol.%.

[0101] The fluorescent emitter used in combination with the compound according to the invention in hyperphosphorescent OLEDs can, in principle, be any fluorescent compound. A person skilled in the art will have no difficulty selecting suitable emitters from a large number of fluorescent emitters without significant effort.

[0102] The fluorescent emitters are preferably purely organic, metal-free compounds or fluorescent metal complexes. Purely organic fluorescent emitters are preferred, and these are preferably sterically shielded.

[0103] A fluorescent compound according to the present invention is a compound capable of emitting light at room temperature under optical excitation in an environment such as that present in the organic electroluminescence device, wherein the emission occurs from an excited singlet state. The compound preferably has a luminescence quantum efficiency of at least 60%, more preferably at least 80%, most preferably at least 90%, and most preferably at least 95%. In a preferred embodiment, the peak emission wavelength lies between 430 and 650 nm.

[0104] In a preferred embodiment of the invention, when producing the emitting layer by vapor deposition, the fluorescent compound is present in the emitting layer at a doping concentration of 0.1 to 25 vol.%, preferably 1 to 20 vol.%, particularly preferably 3 to 10 vol.%, and when producing the layer from solution at a doping concentration of 0.1 to 25 wt.%, preferably 1 to 20 wt.%, particularly preferably 3 to 10 wt.%.

[0105] All compounds used in fluorescent OLEDs according to the state of the art can be used as the basic framework for the fluorescent compound.

[0106] The fluorescent emitter is preferably selected from the following group of fluorescent compounds: styrylamines, indenofluorenes, polyaromatic compounds, anthracenes, tetracenes, xanthenes, perylenes, phenylenes, fluorenes, arylpyrenes, arylenevinylenes, rubrenes, coumarins, rhodamines, quinacridones, dicyanomethylenepyrans, thiopyrans, polymethines, pyrylium and thiapyrylium salts, periflanthenes, indenoperylenes, bis(azinyl)imineborones, bis(azinyl)methines, carbostyryles, monostyrylamines, distyrylamines, tristyrylamines, tetrastyrylamines, styrylphosphines, styryl ethers, arylamines, indenofluorenamines and indenofluorenediamines, benzoindenofluorenamines, benzoindenofluorenediamines. Dibenzoindenofluorenamines, dibenzoindenofluorenediamines, substituted or unsubstituted tristilbenamines, distyrylbenzenes and distyrylbiphenyls, triarylamines, triazole compounds, naphthalenes, phenanthrenes, pyrenes, triazines, chrysenes, decacyclenes, coronenes, tetraphenylcyclopentadienes,Pentaphenylcyclopentadienes, spirofluorenes, pyrans, oxazoles, benzoxazoles, benzothiazoles, benzimidazoles, pyrazines, cinnamic acid esters, diketopyrrolopyrroles and acridones.,

[0107] The steric shielding of these compounds is achieved by electronically inert, sterically demanding substituents that surround the electronically active core of the fluorescent compound and thus largely shield it from contact with neighboring molecules in the layer.

[0108] Preferred fluorescent compounds are stiff π-systems substituted with large aliphatic or cycloaliphatic groups. Aromatic substituents, which may be substituted by aliphatic or cycloaliphatic groups, are also suitable.

[0109] Examples of suitable aromatic parent materials for fluorescent compounds are the groups (1) to (40) listed below.

[0110] Examples of suitable heteroaromatic core structures of fluorescent compounds are the groups of formulas (1) to (40) mentioned above, in which one, two, three, or four carbon atoms of the condensed aromatic ring are replaced by nitrogen. Preferably, one, two, or three carbon atoms are replaced by nitrogen, more preferably one or two carbon atoms, and most preferably exactly one carbon atom.

[0111] Examples of suitable heteroaromatic parent structures of fluorescent compounds are further examples of the groups of formulas (41) to (73) listed below,

[0112] As described above, these structures are substituted by sterically demanding substituents and can also be substituted by further substituents, provided that these substituents are not electronically active or are themselves substituted by sterically shielded substituents.

[0113] The following describes suitable, sterically demanding substituents that can be used to substitute the fluorescent cores, e.g. the aromatics and heteroaromatics mentioned above, and thus to obtain sterically shielded fluorescent compounds.

[0114] Suitable sterically demanding substituents include, for example, alkyl groups, particularly with 3 to 20 carbon atoms, preferably with 4 to 10 carbon atoms, in which hydrogen atoms may also be replaced by fluorine; alkoxy groups, particularly with 3 to 20 carbon atoms, preferably with 4 to 10 carbon atoms; aralkyl groups, particularly with 7 to 30 carbon atoms; and aromatic ring systems, particularly with 6 to 30 carbon atoms, wherein in the aralkyl groups and aromatic ring systems the aryl groups may also be substituted by one or more alkyl groups with 1 to 10 carbon atoms. Several adjacent substituents may also form a ring system together.

[0115] If the substituent is an aralkyl group or an aromatic ring system, it is preferred that it does not contain any fused aryl groups with more than 10 carbon atoms in which aryl groups are directly fused to one another via a common edge. It is particularly preferred that it does not contain any fused aryl groups at all. Thus, it is preferred, for example, that the aromatic ring system does not contain anthracene or pyrene groups, and particularly preferred that the aromatic ring system also does not contain naphthalene groups. In contrast, it may contain, for example, biphenyl or terphenyl groups, since these do not contain any fused aryl groups. Furthermore, it may also contain, for example, fluorene or spirobifluorene groups, since in these groups no aryl groups are directly fused to one another via a common edge.

[0116] If the sterically demanding substituent represents an alkyl group, then this alkyl group preferably has 4 to 10 carbon atoms. Preferably, it is a secondary, tertiary, or cyclic alkyl group in which the secondary or tertiary carbon atom is either directly bonded to the fluorescent core or bonded to the fluorescent core via a CH₂ group. This alkyl group is particularly preferably selected from the structures of the following formulas (R-1) to (R-33): where the dashed line indicates the attachment of these groups to the fluorescent matrix.

[0117] If the sterically demanding substituent represents an alkoxy group, then this alkoxy group preferably has 3 to 10 carbon atoms and is preferably branched or cyclic. This alkoxy group is preferably selected from the structures of the following formulas (R-34) to (R-47): where the dashed line indicates the attachment of these groups to the fluorescent matrix.

[0118] If the sterically demanding substituent represents an aralkyl group, then this aralkyl group is preferably selected from the structures of the following formulas (R-48) to (R-61): where the dashed bond indicates the attachment of these groups to the fluorescent core and the phenyl groups can each be substituted by one or more R< substituents, where: R a< is selected, in each occurrence, from the group consisting of H, D, F, a straight-chain alkyl group with 1 to 40 C atoms or a branched or cyclic alkyl group with 3 to 40 C atoms, each of which may be substituted with one or more R b< substituents, an aromatic ring system with 5 to 60 aromatic ring atoms, each of which may be substituted with one or more R b< substituents, or an aralkyl group with 5 to 60 aromatic ring atoms, which may be substituted with one or more R b< substituents, wherein optionally two or more adjacent R a< substituents may form a ring system which may be substituted with one or more R b< substituents;R< is selected from the group consisting of H, D, F, an aliphatic hydrocarbon residue with 1 to 20 C atoms, an aromatic ring system with 5 to 30 aromatic ring atoms, wherein two or more adjacent substituents R< can form a ring system together; ;

[0119] If the sterically demanding substituent represents an aromatic ring system, then this aromatic ring system has 6 to 60, and preferably 6 to 30, aromatic ring atoms, and particularly preferably 6 to 24 aromatic ring atoms. Furthermore, this aromatic ring system preferably contains only phenyl groups. The aromatic ring system is preferably selected from the structures of the following formulas (R-62) to (R-76): where the dashed bond indicates the attachment of these groups to the fluorescent matrix and the phenyl groups can each be substituted by one or more R a< residues, where R a< is defined as above.

[0120] Examples of fluorescent emitters include aromatic anthracene, aromatic anthracenediamine, aromatic pyrene, aromatic pyrendiamine, aromatic chrysene, and aromatic chrysendiamine. An aromatic anthracene is a compound in which a diarylamine group is directly bonded to an anthracene group, preferably at the 9 position. An anthracenediamine is a compound in which two diarylamine groups are directly bonded to an anthracene group, preferably at the 9,10 position. Aromatic pyrene, pyrendiamine, chrysene, and chrysendiamine are defined analogously, with the diarylamine group preferably bonded at the 1 or 1,6 position of the pyrene.Other preferred emitters are indenofluorenamines, indenofluorenediamines, for example according to WO 2006 / 108497 or WO 2006 / 122630, benzenedofluorenamines or benzenedofluorenediamines, for example according to WO 2008 / 006449, and dibenzoindenofluorenamines or dibenzoindenofluorenediamines, for example according to WO 2007 / 140847, and indenefluorene derivatives with a fused aryl group, as disclosed in WO 2010 / 012328. Other suitable emitters are the benzanthracene derivatives according to WO 2015 / 158409, the anthracene derivatives according to WO 2017 / 036573, fluorine dimers linked via heteroaryl groups, for example according to WO 2016 / 150544, or phenoxazine derivatives, for example according to WO 2017 / 028940 or WO 2017 / 028941. Preferred are the pyrenylarylamines according to WO 2012 / 048780 or WO 2013 / 185871, the benzenedofluorenamines according to WO 2014 / 037077, the benzfluorenamines according to WO 2014 / 106522 and the indenofluorenes according to WO 2014 / 111269, WO 2017 / 036574 or WO 2018 / 007421.Emitters containing dibenzofuran or indenodibenzofuran units are also preferred, for example according to WO 2018 / 095888, WO 2018 / 095940, WO 2019 / 076789, WO 2019 / 170572, WO 2020 / 043657, WO 2020 / 043646 or WO 2020 / 043640. Border derivatives are still preferred, for example according to WO 2015 / 102118, CN 108409769, CN 107266484, WO 2017 / 195669, US 2018 / 0069182, WO 2020 / 208051, as well as according to the unpublished applications EP 19168728.4, EP 19199326.0, EP 19208643.7, EP 19206969.8, EP 19208643.7, EP 19217614.7, EP 19217948.9, EP 20163669.3, EP 20163671.9, EP 20164893.8, EP 20165809.3, EP 20168237.4, EP 20182888.6, EP 20182891.0, EP 20202318.0, EP 20202325.5, EP 20215751.7, EP 20215734.3 and EP 20215718.6. Issuers according to application WO 2020 / 064666 remain preferred.

[0121] The sensitizer, i.e., the compound according to the invention, and the fluorescent emitter can be located in the same layer of an electronic device or in different layers. In a preferred embodiment of the invention, the sensitizer and the fluorescent emitter are located in the same layer, this layer preferably being the emission layer of the OLED.

[0122] Examples of fluorescent emitters are the compounds shown in the table below.

[0123] The layer containing the sensitizer, i.e., the compound according to the invention, and the fluorescent emitter preferably contains at least one further material from the group consisting of electron transport materials, hole conductor materials, quantum materials (preferably quantum dots), bipolar hosts and wide band gap host materials, wherein wide band gap materials are materials having a band gap of 2.5 eV or more, preferably 3.0 eV or more and particularly preferably 3.5 eV or more.

[0124] Suitable matrix materials that can be used in combination with the sensitizer and the fluorescent emitter in the emission layer of the electronic device are the same materials that are described in detail below as matrix materials for phosphorescent emitters. A mixture of an electron-transporting and a hole-transporting matrix material is particularly preferred.

[0125] In a further embodiment, the compound according to the invention is used as an emitting, phosphorescent compound together with one or more host materials (matrix materials) in the emitting layer of an OLED, wherein the emission of the layer then comes from the compound according to the invention.

[0126] When the compound 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. When produced by vapor deposition, the mixture of the compound 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 compound according to the invention, based on the total mixture of emitter and matrix material. Correspondingly, 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. When produced from solution, preferred proportions are those specified above, where these are then expressed as wt% instead of vol%.

[0127] 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.

[0128] 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.

[0129] Preferred biscarbazoles that can be used as matrix materials for the compounds according to the invention are the structures of the following formulas (27) to (33), 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.

[0130] Preferred embodiments are the combinations of the following formulas (27a) to (33a), the symbols used have the meanings mentioned above.

[0131] Examples of suitable compounds according to formulas (27) to (33) are the compounds shown below.

[0132] Preferred dibenzofuran derivatives are the compounds of the following formula (34), 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.

[0133] Preferred carbazolamines are the structures of the following formulas (35), (36) and (37), 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.

[0134] Preferred triazine, pyrimidine, quinazoline or quinoxaline derivatives, which can be used as a mixture together with the compounds according to the invention, are the compounds of the following formulas (38), (39), (40) and (41), where Ar 1< and R have the meanings mentioned above.

[0135] The triazine derivatives of formula (38) and the quinazoline derivatives of formula (40) are particularly preferred, especially the triazine derivatives of formula (38).

[0136] In a preferred embodiment of the invention, Ar 1< in formulas (38) to (41) is, in each instance, the same or different 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. 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 structures Ar-1 to Ar-76.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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).

[0146] 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.

[0147] 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.

[0148] 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).

[0149] 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.

[0150] 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.

[0151] 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.

[0152] The compounds and electronic devices according to the invention, in particular organic electroluminescent devices containing the compounds according to the invention, have the following properties: 1) These compounds are very well suited as sensitizers for fluorescent (hyperphosphorescent) OLEDs. They exhibit particularly efficient energy transfer, low operating voltages, and a long lifetime. 2) When used as phosphorescent emitters, these compounds result in high efficiency, a long lifetime, and low operating voltage. Depending on the choice of ligand, emission ranging from deep blue to deep red can be achieved.

[0153] 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. Examples:

[0154] 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 have several enantiomeric, diastereomeric, or tautomeric forms, one form is shown as a representative example. Example Ir1: a) Chloro-carbonyl complex Ir1a

[0155]

[0156] A mixture of 3.50 g (10.0 mmol) 2,2'-(1-methylethylidene)bis-(6-phenylpyridine) [1056047-22-3], 5.66 g (10.0 mmol) mer-trichlorotris-(tetrahydrothiophene-κS)iridium(III) [35925-64-5], 3.5 ml (30.0 mmol) 2,6-dimethylpyridine [108-48-5], and 100 ml ethylene glycol is stirred for 70 h at 180 °C under a carbon monoxide atmosphere. The mixture is allowed to cool to 80 °C, 300 ml of water is added, and the reaction mixture is extracted three times with 200 ml of dichloromethane (DCM) each time. The combined organic phases are washed three times with 200 ml of water and once with 200 ml of saturated saline solution and dried over magnesium sulfate. The drying agent is filtered off, washed with a small amount of DCM, and concentrated to dryness. The residue is chromatographed with DCM on silica gel, resulting in a yellow spot and an Rf of approximately 0.4. The product fractions are concentrated by rotary evaporation, with the removed DCM being continuously replaced by methanol (MeOH).The yellow solid is filtered off, washed three times with 10 ml of MeOH each time, and then dried under vacuum. Yield: 2.91 g (4.8 mmol), 48%; Purity: 97% by <1H NMR. b) Cyano-carbonyl complex Ir1b

[0157]

[0158] A suspension of 6.04 g (10.0 mmol) of Ir1a in 300 ml of acetonitrile (MeCN) is treated with 38.0 ml (300 mmol) of trimethylsilyl cyanide and heated under reflux until complete conversion (reaction checked by <1H NMR, approx. 80 h). Two-thirds of the solvent is removed under vacuum, the reaction mixture is briefly reheated under strong reflux, allowed to cool to room temperature with stirring, and then stirred for 4 h while cooling in an ice bath. The precipitated microcrystalline precipitate is collected by filtration, washed twice with 20 ml of n-heptane each time, and dried under vacuum. A further product fraction can be obtained by concentration of the mother liquor. Yield: 4.64 g (7.8 mmol), 78%; Purity: 97% by <1H NMR. c) Cyano-tert-butyl-isonitrile complex Ir1

[0159]

[0160] A mixture of 5.95 g (10.0 mmol) of Ir1b, 8.31 g (100 mmol) of tert-butyl isonitrile [7188-38-7], and 100 ml of DMSO is heated to 140 °C for 18 h in a stirred autoclave. After cooling, all volatile components are removed under vacuum at 100 °C. The residue is chromatographed with DCM / n-heptane (5:1) on silica gel, resulting in a yellow spot and an Rf of approximately 0.6. The product fractions are concentrated by rotary evaporation until the DCM is removed. The product is filtered, washed twice with n-heptane, and dried under vacuum. Further purification is achieved by repeated hot extraction crystallization from DCM / acetonitrile mixtures (1:3 to 2:1) followed by fractional sublimation or annealing under high vacuum. Yield: 3.38 g (5.2 mmol), 52%; Purity: approx. 99.9% according to <1H NMR.

[0161] The following connections can be represented analogously: Example. Ligand iso-nitrile Complex yield Ir2 1056047-22-3 23 % 20600-56-0 Ir3 1777013-41-8 25 % 104876-26-8 Ir4 1801620-64-3 20 % 7188-38-7 Ir5 881829-69-2 22 % 7188-38-7 Ir6 881829-72-7 28 % 22110-53-8 Ir7 1777013-37-2 30 % 22110-53-8 Ir8 2015994-30-4 28 % 7188-38-7 Ir9 851540-91-5 19 % 20600-56-0 Ir10 1875090-77-9 33 % 104876-26-8 Ir11 2307698-74-2 30 % 344933-12-6 Ir12 1777013-15-6 25 % 7188-38-7 Ir13 2307699-06-3 27 % Ir14 1777013-19-0 29 % 7188-38-7 Ir15 851540-70-0 34 % 20600-56-0 Ir17 1777012-58-4 30 % Ir18 1446096-29-2 28 % 602262-02-2 Ir19 1566579-88-1 27 % 7188-38-7 Ir20 2054934-85-7 24 % 7188-38-7 Ir21 1619937-91-5 27 % 7188-38-7 Ir22 2305841-75-0 30 % 104876-26-8 Ir23 2054934-52-8 25 % 104876-26-8 Ir24 1700619-29-9 31 % 7188-38-7 Ir25 1393812-52-6 26 % 86559-19-5 Ir26 2230981-86-7 23 % Ir27 2244957-00-2 24 % 86559-19-5 Ir28 1777013-08-7 19 % 602262-03-3 Ir29 125142-49-9 21 % 931-54-4 Ir30 1424362-06-0 23 % 22110-53-8 Ir31 2307699-07-4 26 % 86559-21-9 Ir32 2459309-96-5 25 % 1603834-13-4 Ir33 2133338-99-3 28 % 7188-38-7 Ir34 2252376-55-7 25 % 104876-26-8 Ir35 1546890-05-4 32 % 104876-26-8 Ir36 1366293-31-3 33 % 7188-38-7 Ir37 851540-64-2 31 % 1000698-98-5 Ir38 14458295-96-2 30 % 7188-38-7 Ir39 2084131-70-2 18 % 7188-38-7 Ir40 1777013-53-2 25 % 141399-15-7 Ir41 1619937-87-9 24 % 86559-19-5 Ir42 2054935-53-2 23 % 7188-38-7 Ir43 1835794-90-5 27 % 86559-23-1 Ir44 2054935-50-9 22 % 104876-26-8 Ir45 1792967-95-3 25 % 7188-38-7 Ir46 1414372-83-0 26 % 88523-51-7 Ir47 2412026-94-7 21 % 86559-23-1 Ir48 851540-66-4 23 % 7188-38-7 Ir49 1777012-67-5 31 % 7188-38-7 Ir50 US20160285014 29 % 104876-26-8 Ir51 US20200388774 17 % 7188-38-7 Ir52 2446054-80-2 22 % 7188-38-7 Ir53 1238293-13-4 33 % 86559-23-1 Ir54 1238293-14-5 27 % 7188-38-7 Ir55 1821646-69-8 24 % 88523-50-6 Ir56 EP3266790 28 % 7188-38-7 Ir57 EP3266790 32 % 7188-38-7 Ir58 2460489-47-6 23 % 7188-38-7 Addition of 20 mmol NaO-t-Bu Ir59 2307700-20-3 21 % 86559-23-1 Addition of 20 mmol NaO-t-Bu Isonitrile:

[0162] 7188-38-7 86559-23-1 88523-50-6 86559-19-5 86559-21-9 1000698-98-5 88523-51-7 104876-26-8 22110-53-8 931-54-4 1603834-13-4 20600-56-0 141399-15-7 602262-02-2 602262-03-3 344933-12-6 Manufacturing of OLED components 1) Vacuum-processed components:

[0163] The compounds according to the invention can be used, among other things, as dopants in the emission layer in phosphorescent and hyperphosphorescent OLED components.

[0164] 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).

[0165] The following examples present the results of various OLEDs. Purified 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 AI 4083 from Heraeus Precious Metals GmbH Germany, spin-applied from aqueous solution) for improved processing. The plates are then baked out at 180 °C for 10 minutes. These coated glass plates form the substrates onto which the OLEDs are applied. After fabrication, the OLEDs are encapsulated to protect them from oxygen and water vapor. The exact layer structure of the electroluminescent OLEDs can be seen in the examples.The materials required to manufacture the OLEDs are shown in Table 8.

[0166] The OLEDs are characterized according to standard procedures. This involves calculating the electroluminescence spectra, current efficiency (measured in cd / A), power efficiency (measured in lm / W), and external quantum efficiency (EQE, measured in percent) as a function of luminance. These calculations are derived from current-voltage-luminance curves (IUL curves) assuming a Lambertian emission characteristic. The electroluminescence spectra are determined at a luminance of < 100 cd / m², and the emission color is then derived from these spectra. Phosphorescent OLED components:

[0167] All materials are thermally vapor-deposited in a vacuum chamber. The emission layer (EML) consists of at least one matrix material (host material) TMM and an emitting dopant (Ir), which is added to the matrix material(s) by co-evaporation in a specific volume fraction. A specification such as TMM:Ir (92%:8%) means that the material TMM is present in the layer at a volume fraction of 92% and the dopant Ir at a volume fraction of 8%. However, a mixture of two or more matrix materials (host materials) TMM1, TMM2, etc., and an emitting dopant (Ir) can also be used (see Table 1). The matrix materials TMM1 and TMM2 can be vapor-deposited individually from two different sources or as a mixture from a single source (premixed host).Similarly, the electron transport layer can also consist of a mixture of two materials, e.g., as shown here, of ETM2 (50%) and ETM3 (50%) (see Table 1). The materials used to manufacture the OLEDs are shown in Table 7. Blue Phosphorescent OLED Components BP:

[0168] The OLEDs have the following basic layer structure: Substrate / / Hole injection layer 1 (HIL1) made of HTM1 doped with 5% NDP-9 (commercially available from Novaled), 20 nm / / Hole transport layer 1 (HTL1), HTM1, 180 nm / / Hole transport layer 2 (HTL2), see Table 1 / / Emission layer (EML), see Table 1 / / Electron transport layer (ETL1), see Table 1 / / Electron transport layer (ETL2) made of ETM2 (50%) and ETM3 (50%), 20 nm / / Cathode made of aluminum, 100 nm. Table 1: Structure of Blue Fluorescent OLED Components Example. HTL2 EML ETL1 D-BP1 HTM2 TMM1:TMM2:Ir1 (46%:46%:8%) ETM1 20 nm 10 nm 25 nm D-BP2 HTM2 TMM1:TMM2:Ir53 (50%:42%:8%) ETM1 20 nm 10 nm 25 nm Table 2: Results Example. EQE (%) 100 cd / m²< Voltage (V) 100 cd / m²< CIE color (x / y) D-BP1 18.2 3.3 0.17 / 0.33 D-BP2 19.3 3.5 0.15 / 0.25 Hyperphosphorescent OLED components:

[0169] All materials are thermally vapor-deposited in a vacuum chamber. The emission layer (EML) or layers always consist of at least one or more matrix materials (host materials) TMM, a (phosphorescent) sensitizer Ir, and a fluorescent emitter FE. The sensitizer Ir and the fluorescent emitter FE are added to the host material(s) TMM by co-evaporation in a specific volume fraction. A specification such as TMM:Ir:FE (92%:5%:3%) means that the material TMM is present in the layer at a volume fraction of 92%, Ir at a volume fraction of 5%, and FE at a volume fraction of 3%. A specification such as TMM1:TMM2:Ir:FE (46%:46%:5%:3%) means that the material TMM1 is present in a volume fraction of 46%, the material TMM2 in a volume fraction of 46%, Ir in a volume fraction of 5% and FE in a volume fraction of 3% in the layer. Blue hyperphosphorescent OLED components BH:

[0170] The OLEDs have the following basic layer structure: Substrate / / Hole injection layer 1 (HIL1) made of HTM1 doped with 5% NDP-9 (commercially available from Novaled), 20 nm / / Hole transport layer 1 (HTL1), see Table 3 / / Emission layer (EML), see Table 3 / / Electron transport layer (ETL1), see Table 3 / / Electron transport layer (ETL2) made of ETM2 (50%) and ETM3 (50%), 20 nm / / Cathode made of aluminum, 100 nm. Table 3: Structure of blue hyperphosphorescent OLED components Example. HTL1 EML ETL1 D-BH1 HTM2 TMM1:TMM2:Ir1:FE1 (40%:50%:8%:2%) ETM1 10 nm 10 nm 25 nm D-BH2 HTM2 TMM1:TMM2:Ir53:FE2 ​​(60%:32%:6%:2%) ETM1 10 nm 10 nm 25 nm Table 4: Results Example. EQE (%) 100 cd / m²< Voltage (V) 100 cd / m²< CIE color (x / y) D-BH1 19.9 3.4 0.16 / 0.22 D-BH2 17.0 3.5 0.15 / 0.08 Green hyperphosphorescent OLED components GH:

[0171] The OLEDs have the following basic layer structure: Substrate / / Hole injection layer 1 (HIL1) made of HTM1 doped with 5% NDP-9 (commercially available from Novaled), 20 nm / / Hole transport layer 1 (HTL1) made of HTM1, 30 nm / / Hole transport layer 2 (HTL2), see Table 5 / / Emission layer (EML), see Table 5 / / Electron transport layer (ETL1), see Table 5 / / Electron transport layer (ETL2) made of ETM2 (50%) and ETM3 (50%), 30 nm / / Cathode made of aluminum, 100 nm. Table 5: Structure of green hyperphosphorescent OLED components Example. HTL2 EML ETL2 GH1 HTM2 TMM1:TMM2:Ir10:FE3 ETM1 10 nm (40%:50%:9%:1%) 10 nm 20 nm Table 6: Results Example. EQE (%) 100 cd / m²< Voltage (V) 100 cd / m²< CIE color (x / y) GH1 20.6 3.2 0.32 / 0.65 2) Solution-processed devices: Made from low molecular weight soluble functional materials

[0172] The compounds 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 / / ITO / / hole injection layer, 60 nm / / interlayer, 20 nm / / emission layer, 60 nm / / hole blocking layer, 10 nm / / electron transport layer, 40 nm / / 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 a cleanroom with DI water and a detergent (Deconex 15 PF) and then activated by 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 on a hot plate for 30 minutes at 200 °C. 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 TMM3:TMM4:Ir (w%:x%:z%), where the percentages refer to wt%, see Table 7. The emission layer is spin-deposited in an inert gas atmosphere, in this case argon, and baked out for 10 min at 160 °C. The hole-blocking layer (10 nm ETM2) and the electron transport layer (40 nm ETM2 (50%) / ETM3 (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 then encapsulated and characterized. The OLED examples mentioned are not yet optimized.Table 7 summarizes the data obtained. Table 7: Results with materials processed from solution Example. Emission layer EQE (%) Tension (V) Color 100 cd / m² 100 cd / m² Sol-D1 TMM3:TMM4: Ir23 (20%:60%:20%) 15.7 3.9 red Sol-D2 TMM3:TMM4: Ir40 (20%:60%:20%) 14.1 4.1 red Sol-D3 TMM3:TMM4: Ir41 (20%:60%:20%) 14.5 4.2 red Sol-D4 TMM3: TMM4: Ir51 (20%:60%:20%) 7.0 4.9 red Sol-D5 TMM3:TMM4:Ir12 (20%:60%:20%) 13.2 3.8 yellow Sol-D6 TMM3:TMM4: Ir13 (20%:60%:20%) 14.6 3.8 yellow Sol-D7 TMM3:TMM4: Ir14 (20%:60%:20%) 17.2 3.7 yellow Sol-D8 TMM3:TMM4: Ir7 (20%:60%:20%) 16.8 4.3 green Table 8: Structural formulas of the materials used HTM1 [1450933-44-4] TMM1 / ETM1 [1201800-83-0] HTM2 / TMM2 [1401068-29-8] TMM3 [1616231-60-7] TMM4 1246496-85-4 [2247139-17-7] FE1 [2182628-29-9] FE2 [850219-92-0] FE3 ETM2 [1233200-52-6] ETM3 [25387-93-3]

Claims

1. A compound of Formula (1),         Ir(L)(CN)(CN-R*)     Formula (1), wherein the following applies to the symbols used: R* is an alkyl group with 1 to 20 carbon atoms, which may be substituted by one or more radicals R1, or an aromatic or heteroaromatic ring system with 5 to 30 aromatic ring atoms, which may be substituted by one or more radicals R1; L is a tetradentate ligand of Formula (2), wherein the tetradentate ligand coordinates to the iridium in a square-planar or approximately square-planar manner and the cyano ligand (CN) and the isonitrile ligand (CN-R*) are arranged trans-geometrically above and below the plane formed by the iridiumand the tetradentate ligand in the (pseudo)octahedral complex; wherein * indicates coordination to the iridium the following applies to the symbols and indices: Y1, Y2, Y3, Y4 are the same or different at each occurrence and are selected from the group consisting of C, N or C-O-, with the proviso that at least one of the groups Y1, Y2, Y3 and Y4 is C and that two of the groups Y1, Y2, Y3 and Y4 coordinate to the iridium via an anionic carbon atom, an anionic nitrogen atom or C-O- and the other two of the groups Y1, Y2, Y3 and Y4 coordinate to the iridium via a neutral nitrogen atom or a carbene carbon atom; Ar1, Ar2, Ar3, Ar4 are the same or different at each occurrence and, together with the group Y1, Y2, Y3 or Y4, respectively, form an aryl group having 6 to 16 aromatic ring atoms or a heteroaryl group having 5 to 16 aromatic ring atoms, or an aliphatic carbene having 5 to 10 ring atoms, wherein the aryl or heteroaryl group or the aliphatic carbene may each be substituted by one or more radicals R; A1, A2, A3, A4 are the same or different at each occurrence and are selected from the group consisting of a single bond, CR2, BR, NR, O, S, CR2-CR2, CR=CR, an ortho-linked phenylene group which may be substituted with one or more radicals R, C(=CR2) or CR=N; p is 0 or 1, wherein p = 0 means that the group A4 is not present and instead of A4 residues R can be bound in the corresponding positions of Ar1 and Ar4; 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 be substituted by one or more radicals R1, 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 having 5 to 40 aromatic ring atoms, each of which may be substituted by one or more radicals R1; wherein two radicals R can also form a mono- or polycyclic, aliphatic, heteroaliphatic, aromatic or heteroaromatic ring system with each other; 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 each be substituted by one or more radicals R2, and wherein one or more non-adjacent CH2 groups may be replaced by Si(R2)2, C=O, NR2, O, S or CONR2, or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may each be substituted by one or more radicals R2; and wherein two or more radicals R1 may together form a mono- or polycyclic, aliphatic, heteroaliphatic, aromatic or heteroaromatic 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 hydrocarbon radical, with 1 to 20 carbon atoms, in which one or more H-atoms may also be replaced by F.

2. The compound according to claim 1, characterized in that Ar1 and Ar4 are neutral groups and Ar2 and Ar3 are monoanionic groups, or that Ar1 and Ar4 are monoanionic groups and Ar2 and Ar3 are neutral groups, or that Ar1 and Ar2 are monoanionic groups and Ar3 and Ar4 are neutral groups, or that Ar1 and Ar3 are monoanionic groups and Ar2 and Ar4 are neutral groups.

3. The compound according to claim 1 or claim 2, characterized in that Y1 and Y4 represent anionic carbon atoms and Y2 and Y3 represent neutral nitrogen atoms, or that Y1 and Y4 represent neutral nitrogen atoms and Y2 and Y3 represent anionic carbon atoms, or that Y1 represents a neutral nitrogen atom and Y2 and Y3 represent anionic carbon atoms and Y4 represents a carbene carbon atom, or that Y1 and Y4 represent carbene carbon atoms and Y2 and Y3 represent anionic carbon atoms, or that Y1 and Y3 represent neutral nitrogen atoms and Y2 and Y4 represent anionic carbon atoms, or that Y1 and Y3 represent neutral nitrogen atoms, Y2 represents an anionic carbon atom and Y4 represents C-O-, or that Y1 and Y2 represent neutral nitrogen atoms, Y3 represents an anionic carbon atom and Y4 represents C-O-, or that Y1 represents an anionic carbon atom, Y2 and Y3 represent neutral nitrogen atoms and Y4 represents C-O-.

4. The compound according to one or more of claims 1 to 3, characterized in that Ar1, Ar2, Ar3 and Ar4 together with the group Y1, Y2, Y3 and Y4, respectively, represent, identically or differently at each occurrence, an aryl group having 6 to 10 aromatic ring atoms or a heteroaryl group having 5 to 13 aromatic ring atoms, wherein the aryl or heteroaryl group may each be substituted by one or more radicals R.

5. The compound according to one or more of claims 1 to 4, characterized in that two of the groups A1, A2 and A3 are single bonds and the third group represents a group other than a single bond, and the ligand L is selected from the ligands (L-1) and (L-2), wherein the symbols used have the meanings given in claim 1, Y1 to Y4 are identical or different and represent C or N, and A2 in formula (L-1) or A3 in formula (L-2) does not represent a single bond; or that one of the groups A1, A2 and A3 represents a single bond and the other two groups are identical or different and represent a group other than a single bond and the ligand L is selected from the ligands (L-3) and (L-4), wherein the symbols used have the meanings given in claim 1, and A1 and A3 in formula (L-3) or A2 and A3 in formula (L-4) do not represent single bonds; or that exactly one of the groups Y1 or Y4 represents C-O- and either all three groups A1, A2 and A3 represent a single bond or A1 and A3 represent a single bond and A2 represents C=CR2, wherein a radical R forms an aromatic or heteroaromatic ring with an adjacent group Ar2 or Ar3, and the ligand is selected from the formulae (L-5) and (L-6), wherein the symbols used have the meanings given in claim 1, and A2 in formula (L-6) is C=CR2, wherein at least one radical R forms an aromatic or heteroaromatic ring system with Ar2 or Ar3, or A2 in formula (L-6) is CR2, NR or O; or that none of the groups A1, A2 and A3 represents a single bond and the ligand is selected from the ligands (L-7), wherein the symbols used have the meanings given in claim 1, and A1, A2 and A3 do not represent single bonds.

6. The compound according to one or more of claims 1 to 5, characterized in that Ar1 and Ar4 together with the groups Y1 and Y4, respectively, are each selected from the groups of formulae (Ar-1) to (Ar-44), wherein the group binds to A1 and A3, respectively, at the position indicated by # and coordinates to the iridium at the position indicated by *, wherein R has the meanings given in claim 1, and the following applies to the other symbols used: 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 cycle represent N; W is the same or different at each occurrence, and is NR, O or S; and that Ar2 and Ar3 together with the groups Y2 and Y3 are selected from the groups of the formulae (Ar-45) to (Ar-74), wherein the group binds to A1 and A2 or to A2 and A3 at the position indicated by # and coordinates to the iridium at the position indicated by *, wherein R is as defined in claim 1 and X and W have the meanings given above.

7. The compound according to one or more of claims 1 to 6, characterized in that A1 and / or A3 represent single bonds and the bidentate partial ligands Ar1-Ar2 and Ar3-Ar4 formed in this way are selected from the structures of the formulae (L'-1-1) to (L'-1-3) and (L1-2-1) to (L1-2-5), which coordinate to the iridium via the two positions indicated with *, wherein the symbols used have the meanings given in claims 1 and 6 and # represents the position of the bond to A2.

8. The compound according to claim 5, characterized in that the ligands (L-1) are selected from the structures of formulae (L-1-1) to (L-1-4), wherein A2 and X have the meanings given in claims 1 and 6, and either E is N and the groups Y in the same cycle are the same or different at each occurrence and represent CR or N, or E is C and the groups Y in the same cycle are the same or different at each occurrence and represent CR, N, NR, O or S, with the proviso that exactly one group Y is NR, O or S and the other groups Y are the same or different, and are CR or N; and that the ligand (L-4) is selected from the ligands (L-4-1) to (L-4-3), wherein the symbols used have the meanings given in claims 1 and 6 and above, E and Y have the meanings given above, and A2 does not represent a single bond; and that the ligand (L-6) is selected from the ligands of the formula (L-6-1) and (L-6-2), wherein the symbols used have the meanings given in claims 1 and 6, and E and Y have the meanings given above; and that the ligands (L-7) are selected from the ligands of formula (L-7-1), wherein the symbols used have the meanings given in claims 1 and 6, and A2 does not represent a single bond.

9. The compound according to claim 8, characterized in that the ligands (L-1) are selected from the structures (L-1-1a) to (L-1-4c), wherein the symbols have the meanings given in claim 1; and that the ligands (L-4) are selected from the ligands (L-4-1a) to (L-4-3a), wherein the symbols have the meanings given in claim 1, and A2 does not represent a single bond; and that the ligands (L-6) are selected from the formulae (L-6-1a) and (L-6-2a) to (L-6-2c), wherein the symbols have the meanings given in claim 1; and that the ligands (L-7) are selected from the ligands of formula (L-7-1a), wherein the symbols have the meanings given in claim 1 and A2 does not represent a single bond.

10. The compound according to one or more of claims 1 to 9, characterized in that R* is an alkyl group having 4 to 10 carbon atoms, in which one or more H atoms may also be replaced by D or F, or represents an aromatic ring system having 6 to 12 carbon atoms, wherein the aromatic ring system may be substituted by one or more radicals selected from F, D or an alkyl group having 1 to 10 carbon atoms, wherein one or more H atoms in the alkyl group may be replaced by D or F; wherein several alkyl groups present as substituents on the aromatic ring system may also form a ring system with each other.

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

12. Use of a compound according to one or more of claims 1 to 10 in an electronic device or as an oxygen sensitizer or as a photoinitiator or as a photocatalyst.

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

14. The electronic device according to claim 13, wherein it is an organic electroluminescent device, characterized in that the compound according to one or more of claims 1 to 10 is used in one or more emitting layers as a phosphorescent emitter or as a sensitizer for a fluorescent emitter.