Method for producing ortho-metallated metal compounds

Abstract

To address the problem underlying the present invention, i.e. providing a broadly applicable process by which cyclometalated iridium complexes, especially polypodal cyclometalated iridium complexes, and corresponding polynuclear complexes can be synthesized in a simple manner from readily obtainable iridium reactants, for example iridium(III) halide hydrate or iridium(III) acetate, under mild conditions and in high yield.SOLUTION: The present invention relates to a method for producing cyclo-metallated metal compounds which, in their capacity as functional materials, are used as colouring components in a range of diverse applications attributable in the widest sense to the electronics industry.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for preparing cyclometallated iridium compounds from simple iridium reactants. [Background technology]

[0002] Organometallic iridium compounds are used as functional materials in many diverse and widely applicable applications in the electronics industry, in particular as phosphorescent emitters in organic electroluminescent devices. This requires efficient chemical synthesis to the corresponding high-purity organometallic compounds. Considering the scarcity of Ir, resource-conserving use of these compounds is of great importance.

[0003] Various methods are known for the preparation of cyclometallated organoiridium compounds. What they have in common is that they are carried out in organic solvents or mixtures of organic solvents and water, often at high temperatures and long reaction times. When chlorine-containing iridium reactants are used, silver salts are often used to remove the chlorine, but this creates purity problems for the iridium complexes. Therefore, the use of silver salts is not preferred.

[0004] For example, methods are known in the melt using high-melting protic compounds, such as hydroquinone, phenol, naphthol, resorcinol, catechol, polyethylene glycol and mixtures thereof. These compounds have been found to be good reaction media, especially for cyclometallation reactions with polypodal ligands (e.g. WO2016 / 124304) or other corresponding binuclear complexes (e.g. WO2018 / 041769). Above 240° C. in the melt, the orthometallation reaction proceeds rapidly, selectively and without significant side reactions. The removal of water- and alcohol-soluble reaction media is excellent, since the reaction products are insoluble in these media. In laboratory operations, the reaction is therefore carried out with very good space, time and yield. In contrast, it is technically difficult to scale up this method to a production-scale batch reaction operation, since it is technically very difficult to heat relatively large volumes rapidly and without overheating to the required temperatures above 240° C., or to cool them again after the reaction. Furthermore, it has been found to be disadvantageous that the reaction mixture solidifies as it cools, which leads to problems with stirring and work-up. A further factor is the particular safety requirements in such high-temperature processes, which in practice put very high demands on the plant and building infrastructure (e.g. separate buildings due to the large ex-zones). Furthermore, in the scale-up of the process, pyrophoric iridium has been observed in some cases, which leads to self-ignition when the crude product is sucked dry under air, thus representing a major safety risk. Therefore, improvements are still required. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] WO2016 / 124304 [Patent Document 2] WO2018 / 041769 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem underlying the present invention is therefore to provide a broadly applicable method by which cyclometallated iridium complexes, in particular polypodal cyclometallated iridium complexes, and the corresponding polynuclear complexes, can be synthesized in a simple manner, in mild conditions and in high yields from easily obtainable iridium reactants, such as iridium(III) halide hydrates or iridium(III) acetate. It is a particular problem to provide a broadly applicable method for the synthesis of polypodal cyclometallated complexes and the corresponding polynuclear complexes without the addition of silver salts. Moreover, in this method, no pyrophoric by-products are formed. Moreover, the reactants and reaction media are non-toxic and commercially readily available. A further problem solved by the present invention is to provide a method that can proceed not only from iridium halides, but also from halogen-free, in particular chlorine-free, reactants. The reaction in this case should be carried out in an inert reactor, for example glass or enamel, in the case of the use of chlorine-containing reactants, although stainless steel reactors are also possible. [Means for solving the problem]

[0007] Surprisingly, it has been found that the synthesis of cyclometallated iridium complexes proceeding from a variety of iridium(III) or iridium(I) reactants (e.g., iridium halides, iridium acetate, or other iridium reactants) can be carried out in high yields and purity in anhydrous organic carboxylic acids, where the reactions proceed under relatively mild conditions, i.e., temperatures below 190° C. and at low pressures.

[0008] The invention therefore relates to a process for the preparation of a cyclometallated iridium complex by reacting an iridium compound with one or more ligands which coordinate to the iridium under cyclometallation, characterized in that the process is carried out in the presence of a carboxylic acid and in an anhydrous medium.

[0009] In the sense of the present invention, a cyclometallated iridium complex is an iridium complex having at least one bidentate cyclometallated ligand or subligand. Here, the iridium complex may be mononuclear or polynuclear, for example dinuclear or trinuclear. Preferably, it is a triscyclometallated iridium complex having three bidentate cyclometallated ligands or subligands. In the sense of the present invention, the term "cyclometallated iridium complex" also includes iridium complexes in which three bidentate ligands, at least one of which is cyclometallated, are covalently linked to each other via a bridge, thereby forming a tripodal hexadentate ligand. The same applies to multipodal complexes. In the sense of the present invention, a cyclometallated ligand is a ligand that forms a metal cycle with a metal and is coordinated to the metal such that at least one metal-carbon bond exists between the ligand and the metal.

[0010] Depending on the ligands, either homoleptic or heteroleptic metal complexes can be synthesized. Homoleptic complexes are understood to mean compounds in which only identical ligands are bound to the metal. Heteroleptic complexes are those in which different ligands are bound to the metal. This applies to ligands with different basic structures as well as ligands with the same basic structure but different substitutions.

[0011] In a preferred form of the invention, the cyclometallated iridium complex is a homoleptic complex when the three bidentate ligands are not covalently linked via bridges to form a tripodal hexadentate ligand. When the three bidentate ligands are covalently linked via bridges to form a tripodal hexadentate ligand, it is likewise preferred that the bidentate subligands of each of the tripodal ligands are different from each other.

[0012] In a further preferred embodiment of the invention, the cyclometallated iridium complex is a facial isomer of the complex. In the sense of the invention, facial or meridional coordination refers to an octahedral environment of iridium with six donor atoms. Facial coordination occurs when three identical donor atoms occupy a triangular face in a (pseudo)octahedral coordination polyhedron, and three identical donor atoms different from the first occupy another triangular face in the (pseudo)octahedral coordination polyhedron. In meridional coordination, three identical donor atoms occupy one meridian in the (pseudo)octahedral coordination polyhedron, and three identical donor atoms different from the first occupy the other meridian in the (pseudo)octahedral coordination polyhedron. This is illustrated below by an example of the coordination of three donor nitrogen atoms and three donor carbon atoms (Scheme 1). Since this definition relates to the donor atoms and not to the bidentate ligands that donate these donor atoms, the three bidentate cyclometalating ligands may be identical or different, nevertheless corresponding to facial or meridional coordination within the meaning of the present invention. Identical donor atoms are understood to be those consisting of identical elements (e.g. carbon or nitrogen), regardless of whether these elements are incorporated into different structures. Scheme 1: [ka]

[0013] The iridium complex obtained by the method of the present invention preferably has a structure represented by the following formula (1), (2) or (3). [ka] Where: L is the same or different at each occurrence and is a bidentate cyclometallated ligand in formula (2), or a bidentate cyclometallated ancillary ligand in formulas (1) and (3); L' is the same or different at each occurrence and is a bidentate ligand in formula (2) or a bidentate ancillary ligand in formulas (1) and (3); L″ is a bisbidentate cyclometallated ancillary ligand coordinated to both iridium atoms; V is the same or different in each occurrence and is a bridging unit which links the ancillary ligands L and L′ to one another to form a tripodal hexadentate ligand in formula (1) and which links the ancillary ligands L and L′ to one another to form an overall dodecadentate ligand in formula (3).

[0014] The ligand used in the process of the present invention, in the complex of formula (1), corresponds to a compound of formula (4). [ka] where the symbols have the definitions given above, the ancillary ligand L has a carbon-hydrogen bond rather than a carbon-iridium bond, and the ancillary ligand L' has a hydrogen atom rather than a bond to iridium.

[0015] The ligands used in the methods of the invention correspond to L and L' in the complex of formula (2), where ligand L has a carbon-hydrogen bond rather than a carbon-iridium bond, and ligand L' has a hydrogen atom rather than a bond to iridium.

[0016] The ligand used in the process of the present invention, in the complex of formula (3), corresponds to a compound of formula (5). [ka] where the symbols have the definitions given above, the ancillary ligand L'' has a carbon-hydrogen bond rather than a carbon-iridium bond, and the ancillary ligand L' has a hydrogen atom rather than a bond to iridium.

[0017] Here, the bidentate or ancillary ligand L' may be cyclometallated or non-cyclometallated, and L and L' in formulae (1) and (2) may be the same when L' is a cyclometallated ligand.

[0018] In a preferred form of the invention, L and L' are monoanionic ligands and L'' is a dianionic ligand.

[0019] The ligand of formula (4) in the complex of formula (1) is a tripodal hexadentate ligand with three bidentate subligands L and L', which may be the same or different. "Bidentate" means that the particular subligand in the complex coordinates or bonds to the iridium via two coordination sites. "Tripodal" means that the ligand has three subligands, which are attached to a bridge V. Since the ligand has three bidentate subligands, overall it is a hexadentate ligand, i.e. a ligand that coordinates or bonds to the iridium via six coordination sites. In the sense of the present invention, the expression "bidentate subligand" means that in the absence of the bridge V, L and L' are bidentate in each case. However, with the hydrogen atom formally removed from this bidentate ligand and its connection to bridge V, it is no longer a separate ligand but is instead part of a hexadentate ligand, hence the term "ancillary ligand".

[0020] The ligand of formula (5) in the ligand of formula (3) is a dodecadent bistripodal ligand coordinated to two iridium atoms, where the ligand contains two bidentate antimetas L' in each of the two halves, each coordinated to one of the two iridium atoms, and a bisbidentate antimetas L'' coordinated to both iridium atoms.

[0021] In a preferred embodiment of the invention, the ligand L' is a bidentate cyclometallated ligand or an ancillary ligand. Thus, the metal complexes obtainable by the process of the invention preferably have the structure of formula (1a), (2a) or (3a) below: [ka] Here, the symbols used have the definitions given above.

[0022] Below, the bidentate cyclometallated ligand or ancillary ligand L is described. When L' is a bidentate cyclometallated ligand or ancillary ligand, the following preferences also apply to L'. The ligand or ancillary ligand L coordinates to iridium via one carbon atom and one nitrogen atom, or via two carbon atoms. When L coordinates to iridium via two carbon atoms, one of the two carbon atoms is a carbene carbon atom. In a preferred embodiment of the present invention, at least two ligands or ancillary ligands L and L' are identical. In the complex of formula (2), preferably, all ligands L and L' are identical, and the complex is a homoleptic complex.

[0023] More preferably, each ligand or subligand L and L' has one carbon atom and one nitrogen atom as coordination atoms.

[0024] It is further preferred if the metallocycle formed from iridium and the ligands or subligands L and L' is a five-membered ring, as shown diagrammatically hereinafter. [ka] where N is a coordinating nitrogen atom, C is a coordinating carbon atom and the carbon atom shown is an atom of a ligand or subligand L or L'.

[0025] In a preferred embodiment of the invention, the ligands or ancillary ligands L and, where appropriate, L', which are identical or different on each occurrence, are of the structures of the following formulae (L-1) and (L-2): [ka] where the dotted line is the attachment of the ancillary ligand to bridge V in formula (1) or (3) and is not present in formula (2), and where the other symbols used are: CyC, which may be the same or different at each occurrence, is a substituted or unsubstituted aryl or heteroaryl group having 5 to 14 aromatic ring atoms, which in each case is coordinated to the metal via a carbon atom and bonded to CyD via a covalent bond; CyD, which may be the same or different at each occurrence, is a substituted or unsubstituted heteroaryl group having 5-14 aromatic ring atoms, coordinated to the metal through a nitrogen atom or through a carbene carbon atom, and bonded to CyC through a covalent bond; At the same time, two or more optional substituents may together form a ring system; the optional radicals are preferably selected from the R radicals defined below.

[0026] CyD coordinates via an uncharged nitrogen atom or via a carbene carbon atom, and CyC coordinates via an anionic carbon atom.

[0027] The R radicals on CyC and CyD are preferably: R is the same or different at each occurrence and is H, D, F, Cl, Br, I, N(R 1 )2, OR 1 , S.R. 1 , CN, NO2, COOR 1 , C(=O)N(R 1 )2, Si(R 1 )3, B(OR 1 )2, C(=O)R 1 , P(=O)(R 1 )2, S(=O)R 1 , S(=O)2R 1 , OSO2R 1 , a linear alkyl group having 1 to 20 carbon atoms, or an alkenyl or alkynyl group having 2 to 20 carbon atoms, or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group is in each case composed of one or more R 1 radical, where one or more non-adjacent CH groups are Si(R 1 )2, C=O, NR 1 , O, S or CONR1 or having 5 to 40 aromatic ring atoms, in each case having one or more non-aromatic R 1 an aromatic or heteroaromatic ring system, optionally substituted by a radical; at the same time, two R radicals may together form a ring system; R 1 are the same or different for each occurrence and are H, D, F, Cl, Br, I, N(R 2 )2, OR 2 , S.R. 2 , CN, NO2, Si(R 2 )3, B(OR 2 )2, C(=O)R 2 , P(=O)(R 2 )2, S(=O)R 2 , S(=O)2R 2 , OSO2R 2 , a linear alkyl group having 1 to 20 carbon atoms, or an alkenyl or alkynyl group having 2 to 20 carbon atoms, or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group is in each case composed of one or more R 2 radical, where one or more non-adjacent CH groups are Si(R 2 )2, C=O, NR 2 , O, S or CONR 2 or having 5 to 40 aromatic ring atoms, in each case having one or more R 2 an aromatic or heteroaromatic ring system, optionally substituted by radicals; 1 the radicals together may form a ring system; R 2 is the same or different at each occurrence and is H, D, F, or an aliphatic organic radical, especially a hydrocarbyl radical, having 1 to 20 carbon atoms, in which one or more hydrogen atoms may be replaced by F.

[0028] Two R's or R's 1When the radicals together form a ring system, this may be monocyclic or polycyclic, aliphatic, heteroaliphatic, aromatic or heteroaromatic. In this case, the radicals together forming a ring system may be adjacent, meaning that they are attached to the same carbon atom or to carbon atoms directly adjacent to each other, and they may further be removed from each other. Furthermore, the substituents on CyC and CyD may together form a ring, so that CyC and CyD together form a single fused aryl or heteroaryl group as a bidentate ligand.

[0029] In the sense of the present invention, the term two or more radicals may together form a ring is understood to mean, inter alia, that two radicals are linked to each other by a chemical bond with the formal deletion of two hydrogen atoms, as illustrated by the following scheme: [ka]

[0030] Furthermore, the above terms are also understood to mean that when one of the two radicals is hydrogen, the second radical is attached at the position where the hydrogen atom is attached to form a ring, as shown by the following scheme: [ka]

[0031] Furthermore, the above terms are understood to mean that when two radicals are alkenyl groups, the radicals together form a ring to form a fused aryl group. Similarly, in the case of an aryloxy substituent, the formation of a fused benzofuran group is also possible, and in the case of an arylamino substituent, the formation of a fused indole group is also possible. These are illustrated by the following schemes: [ka]

[0032] In the sense of the present invention, the term "alkyl group" is a generic term that includes both linear or branched alkyl groups and cyclic alkyl groups. Similarly, "alkenyl group" and "alkynyl group" are generic terms that include linear or branched alkenyl or alkynyl groups and cyclic alkynyl groups.

[0033] In the sense of the present invention, a cyclic, alkyl, alkoxy or thioalkoxy group is taken to mean a mono-, bi- or polycyclic group.

[0034] In the sense of the present invention, C1- to C 20-Alkyl groups (furthermore, each of the hydrogen atoms or CH2 groups may be replaced by the groups mentioned above) are, for example, 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, neopentyl, cyclopentyl, n-hexyl, s-hexyl, t-hexyl, 2-hexyl, 3-hexyl, neohexyl, cyclohexyl, 1- Methylcyclopentyl, 2-methylpentyl, n-heptyl, 2-heptyl, 3-heptyl, 4-heptyl, cycloheptyl, 1-methylcyclohexyl, n-octyl, 2-ethylhexyl, cyclooctyl, 1-bicyclo[2.2.2]octyl, 2-bicyclo[2.2.2]octyl, 2-(2,6-dimethyl)octyl, 3-(3,7-dimethyl)octyl, adamantyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, 1,1-dimethyl-n-hexyl 1,1-dimethyl-n-hept-1-yl, 1,1-dimethyl-n-oct-1-yl, 1,1-dimethyl-n-dec-1-yl, 1,1-dimethyl-n-dodec-1-yl, 1,1-dimethyl-n-tetradec-1-yl, 1,1-dimethyl-n-hexadec-1-yl, 1,1-dimethyl-n-octadec-1-yl, 1,1-diethyl-n-hex-1-yl, 1,1-diethyl-n-hept-1-yl, 1,1-diethyl-n-oct-1-yl, 1,1-diethyl-n -dec-1-yl, 1,1-diethyl-n-dodec-1-yl, 1,1-diethyl-n-tetradec-1-yl, 1,1-diethyl-n-hexadec-1-yl, 1,1-diethyl-n-octadec-1-yl, 1-(n-propyl)cyclohex-1-yl, 1-(n-butyl)cyclohex-1-yl, 1-(n-hexyl)cyclohex-1-yl, 1-(n-octyl)cyclohex-1-yl- and 1-(n-decyl)cyclohex-1-yl radicals. Alkenyl groups are understood to mean, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl or cyclooctadienyl.An alkynyl group is understood to mean, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl or octynyl. OR. 1 The radicals are taken to mean, for example, methoxy, trifluoromethoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy or 2-methylbutoxy.

[0035] An aryl group, in the sense of the present invention, contains 6 to 30 carbon atoms; a heteroaryl group, in the sense of the present invention, contains 2 to 30 carbon atoms and at least one heteroatom, with the proviso that the sum of carbon atoms and heteroatoms is at least 5. The heteroatoms are preferably selected from N, O and / or S. An aryl or heteroaryl group is understood here to mean a single aromatic ring, i.e. benzene, or a single heteroaromatic ring, such as pyridine, pyrimidine, thiophene, etc., or a condensed aryl or heteroaryl group, such as naphthalene, anthracene, phenanthrene, quinoline, isoquinoline, etc. Aromatic systems linked to one another by a single bond (for example biphenyl), in contrast, are not referred to as aryl or heteroaryl groups, but as aromatic ring systems.

[0036] In the sense of the present invention, aromatic ring systems have 6 to 40 carbon atoms, preferably 6 to 30 carbon atoms, in the ring system. In the sense of the present invention, heteroaromatic ring systems contain 2 to 40 carbon atoms, preferably 2 to 30 carbon atoms, and at least one heteroatom in the ring system, with the proviso that the sum of carbon atoms and heteroatoms is at least 5. The heteroatoms are preferably selected from N, O and / or S. In the sense of the present invention, aromatic or heteroaromatic ring systems should be understood to mean systems which do not necessarily contain only aryl or heteroaryl groups, but in which two or more aryl or heteroaryl groups can also be linked by non-aromatic units, such as carbon, nitrogen or oxygen atoms. These are likewise understood to mean systems in which two or more aryl or heteroaryl groups are directly bonded to each other, such as biphenyls, terphenyls, bipyridines or phenylpyridines. For example, systems such as fluorene, 9,9'-spirobifluorene, 9,9-diarylfluorene, triarylamine, diaryl ether, stilbene, etc. are also considered as aromatic ring systems in the sense of the present invention, as are systems in which two or more aryl groups are linked, for example by short alkyl groups. Preferred aromatic or heteroaromatic ring systems are simple aryl or heteroaryl groups, and groups in which two or more aryl or heteroaryl groups are directly linked to each other (for example biphenyl or bipyridine), and fluorene or spirobifluorene.

[0037] having 5 to 40 aromatic ring atoms, in each case as defined above for R 2The aromatic or heteroaromatic ring systems, which may be substituted by radicals or hydrocarbyl radicals and which may be linked to the aromatic or heteroaromatic ring system via any position, are in particular benzene, naphthalene, anthracene, benzanthracene, phenanthrene, pyrene, chrysene, perylene, fluoranthene, benzofluoranthene, naphthacene, pentacene, benzopyrene, biphenyl, biphenylene, terphenyl, terphenylene, fluorene, spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, propylene, cis- or trans-indenofluorene, cis- or trans-indenocarbazole, cis- or trans-indolocarbazole, truxene, isotruxene, spirotruxene, spiroisotruxene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, pyridine, quinoline, isoquinoline, acridine, phenanthridine, benzo-5,6-quinoline, benzo-6, 7-Quinoline, Benzo-7,8-quinoline, Phenothiazine, Phenoxazine, Pyrazole, Indazole, Imidazole, Benzimidazole, Naphthoimidazole, Phenanthrimidazole, Pyridimidazole, Pyrazinimidazole, Quinoxalinimidazole, Oxazole, Benzoxazole, Naphthoxazole, Anthroxazole, Phenanthroxazole, Isoxazole, 1,2-Thiazole, 1,3-Thiazole, Benzothiazole, Pyridazine, Hexaazatriphenylene, Benzopyridazine, Pyrimidine, Benzopyrimidine , quinoxaline, 1,5-diazaanthracene, 2,7-diazapyrene, 2,3-diazapyrene, 1,6-diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene, 4,5,9,10-tetraazapyrylene, pyrazine, phenazine, phenoxazine, phenothiazine, fluorubine, naphthyridine, azacarbazole, benzocarboline, phenanthroline, 1,2,3-triazole, 1,2,4-triazole, benzotriazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,It is understood to mean radicals derived from 4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, tetrazole, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, purine, pteridine, indolizine and benzothiadiazole, or radicals derived from combinations of these systems.

[0038] Preferably, all of the ligands or ancillary ligands L and, where appropriate, L' have the structure of formula (L-1) or all of the ligands or ancillary ligands L and, where appropriate, L' have the structure of formula (L-2).

[0039] In a preferred form of the invention, CyC is an aryl or heteroaryl group having 6 to 13 aromatic ring atoms, more preferably having 6 to 10 aromatic ring atoms, most preferably having 6 aromatic ring atoms, which coordinates to the metal via a carbon atom, which may be substituted by one or more R radicals, and is attached to CyD via a covalent bond.

[0040] Preferred forms of the CyC group are the structures of the following formulae (CyC-1) to (CyC-20), where in each case the CyC group is bonded to CyD at the position marked with # and coordinates to iridium at the position marked with *. [ka] where R is as described above, and further: X is the same or different at each occurrence and is CR or N, with the proviso that up to two symbols X per ring are N; W is the same or different at each occurrence and is NR, O, S or BR; However, if a bridge V is bonded to a CyC in formula (1) or (3), one symbol X is C and the bridge V is bonded to this carbon atom. If a CyC group is bonded to the bridge V, the bond is preferably via the position marked with "o" in the above formula, in which case the symbol X marked with "o" is preferably C. The above structures not containing any symbol X marked with "o" are preferably not bonded directly to the bridge V, since a bond to such a bridge is not advantageous for bulky reasons.

[0041] Preferably, not more than one of the symbols X in CyC is N, and more preferably, all of the symbols X are CR, with the proviso that when a bridge V in formula (1) is attached to CyC, one symbol X is C and the bridge V is attached to this carbon atom.

[0042] Preferred CyC groups are those of the following formulae (CyC-1a) to (CyC-20a):

[0043] [ka]

[0044] [ka]

[0045] wherein the symbols used have the meanings described above, and in case the bridge V is bonded to CyC in formula (1) or (3), one R radical is absent and the bridge V is bonded to the corresponding carbon atom. In case the CyC group is bonded to the bridge V, the bond is preferably via the position marked with "o" in the above formula, in which case the R radical in this position is preferably absent. The above structures which do not contain any carbon atom marked with "o" are preferably not bonded directly to the bridge V.

[0046] Among the (CyC-1) to (CyC-19) groups, preferred are (CyC-1), (CyC-3), (CyC-8), (CyC-10), (CyC-12), (CyC-13) and (CyC-16) groups, and particularly preferred are (CyC-1a), (CyC-3a), (CyC-8a), (CyC-10a), (CyC-12a), (CyC-13a) and (CyC-16a) groups.

[0047] In a further preferred embodiment of the invention, CyD is a heteroaryl group having 5-13 aromatic ring atoms, more preferably 6-10 aromatic ring atoms, coordinated via an uncharged nitrogen atom or via a carbene carbon atom, optionally substituted by one or more R radicals, and attached to CyC via a covalent bond.

[0048] Preferred forms of the CyD group are structures of the following formulae (CyD-1) to (CyD-12), in which the CyD group is in each case bonded to CyC at the position indicated by # and to iridium at the position indicated by *.

[0049] [ka] where X, W and R have the meanings given above, with the proviso that if the bridge V in formula (1) or (3) is linked to CyD, then one symbol X is C and the bridge V is linked to this carbon atom. If a CyD group is linked to the bridge V, then the linkage is preferably via the position marked "o" in the above formula, so that in this case the symbol X marked "o" is preferably C. The above structures not containing the symbol X marked "o" are preferably not linked directly to the bridge V, since a linkage to such a bridge is not favoured for steric reasons.

[0050] In this case, the (CyD-1) to (CyD-4) and (CyD-7) to (CyD-12) groups coordinate to iridium via uncharged nitrogen atoms, and the (CyD-5) and (CyD-6) groups coordinate to iridium via carbene carbon atoms.

[0051] Preferably, not more than one of the symbols X in CyD is N, more preferably all of the symbols X are CR, with the proviso that when a bridge V in formula (1) or (3) is attached to CyD, one symbol X is C and the bridge V is attached to this carbon atom.

[0052] Particularly preferred CyD groups are those of the following formulae (CyD-1a) to (CyD-12b): [ka] wherein the symbols used have the meanings described above, and in case the bridge V is linked to CyD in formula (1) or (3), one R radical is absent and the bridge V is linked to the corresponding carbon atom. In case the CyD group is linked to the bridge V, the linkage is preferably via the position indicated by "o" in the above formula, in which case the R radical in this position is preferably absent. The above structures not containing the carbon atom indicated by "o" are preferably not directly linked to the bridge V.

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

[0054] In a preferred embodiment of the invention, CyC is an aryl or heteroaryl group having 6 to 13 aromatic ring atoms and CyD is a heteroaryl group having 5 to 13 aromatic ring atoms. More preferably, CyC is an aryl or heteroaryl group having 6 to 10 aromatic ring atoms and CyD is a heteroaryl group having 5 to 10 aromatic ring atoms. Most preferably, CyC is an aryl or heteroaryl group having 6 aromatic ring atoms and CyD is a heteroaryl group having 6 to 10 aromatic ring atoms. At the same time, CyC and CyD may be substituted by one or more R radicals.

[0055] The above preferred groups (CyC-1) to (CyC-20) and (CyD-1) to (CyD-12) may be optionally linked to each other, where in the compound of formula (1) or (3), it is necessary that at least one of the CyC or CyD groups has a suitable linkage site to the bridge V, the suitable linkage site in the above formula being marked with "o".

[0056] It is particularly preferred that the CyC and CyD groups described as being preferred (i.e. groups of formulae (CyC-1a) to (CyC-20a) and (CyD1-a) to (CyD-14b)) are linked to one another.

[0057] It is particularly preferred that one of the (CyC-1), (CyC-3), (CyC-8), (CyC-10), (CyC-12), (CyC-13) and (CyC-16) groups, in particular the (CyC-1a), (CyC-3a), (CyC-8a), (CyC-10a), (CyC-12a), (CyC-13a) and (CyC-16a) groups, is bound to one of the (CyD-1), (CyD-2) and (CyD-3) groups, in particular to one of the (CyD-1a), (CyD-2a) and (CyD-3a) groups.

[0058] Preferred ancillary ligands (L-1) are structures represented by formulae (L-1-1) and (L-1-2), and preferred ancillary ligands (L-2) are structures represented by formulae (L-2-1) to (L-2-4). [ka] wherein the symbols used have the definitions given above, and "o" in the compounds of formula (1) or (3) indicates the point of attachment to the bridge V, in this case the corresponding X is C.

[0059] Particularly preferred ancillary ligands (L-1) are structures represented by formulae (L-1-1a) and (L-1-2b), and particularly preferred ancillary ligands (L-2) are structures represented by formulae (L-2-1a) to (L-2-4a). [ka] Here, the symbols used have the meanings described above, and "o" in formula (1) or (3) indicates the position of attachment to the bridge V, in which case the corresponding R is absent.

[0060] When the two R radicals, one attached to CyC and the other to CyD, together form a ring system, this results in a bridged ligand or subligand L or L', in which case several of these bridged subligands together form one larger heteroaryl group, such as benzo[h]quinoline. The ring between the substituents on CyC and CyD is preferably formed by a group of one of the following formulae (6) to (15): [ka] Here, R 1 has the meaning described above, and the dotted bond denotes the bond to CyC and CyD, where each of the asymmetric groups mentioned above may be incorporated in two possible ways. For example, in the group of formula (15), the oxygen atom may be bonded to the CyC group and the carbonyl group to the CyD group, or the oxygen atom may be bonded to the CyD group and the carbonyl group to the CyC group.

[0061] At the same time, the group of formula (12) is particularly preferred when it forms a 6-membered ring, for example, as shown in formulae (L-21) and (L-22).

[0062] Preferred ligands resulting from ring formation between two R radicals on different rings are structures of formulae (L-3) to (L-30) shown below. [ka]

[0063] [ka] wherein the symbols used have the definitions given above, and "o" in formula (1) or (3) indicates the position at which the ancillary ligand is attached to the V group, and the corresponding symbol X is C.

[0064] In a preferred embodiment of the ligands or ancillary ligands of formulae (L-3) to (L-30), in total one symbol X is N and another symbol X is CR, or all symbols X are CR.

[0065] In a further embodiment of the invention, it is preferred that in the (CyC-1) to (CyC-20) or (CyD-1) to (CyD-14) groups or in the ligands or ancillary ligands (L-1-1) to (L-30), one of the atoms X is N, if the R group attached as a substituent adjacent to the nitrogen atom is not hydrogen or deuterium. This applies analogously to the preferred structures (CyC-1a) to (CyC-20a) or (CyD-1a) to (CyD-14b), where the substituent attached adjacent to the non-coordinating nitrogen atom is preferably an R group which is not hydrogen or deuterium. In this case, this substituent R is preferably CF3, OCF3, an alkyl group having 1 to 10 carbon atoms, in particular a branched or cyclic alkyl group having 3 to 10 carbon atoms, OR 1 (where R 1is a group selected from an alkyl group having 1 to 10 carbon atoms, particularly a branched or cyclic alkyl group having 3 to 10 carbon atoms, a dialkylamino group having 2 to 10 carbon atoms, or an aryl or heteroaryl group having 5 to 10 aromatic ring atoms. These groups are sterically bulky groups. More preferably, this R radical may form a ring with the adjacent R radical.

[0066] Further preferred bidentate ligands or ancillary ligands are those of the formula (L-31) or (L-32) below: [ka] Here, R has the meaning described above, * indicates the coordination position to iridium, "о" in formula (1) or (3) indicates the attachment position of the ancillary ligand to V, and other symbols used are as follows: X is the same or different at each occurrence and is CR or N, with the proviso that not more than one symbol X per ring is N. When two R radicals attached to adjacent carbon atoms in the ligands or ancillary ligands (L-31) and (L-32) form an aromatic ring together, this ring together with the two adjacent carbon atoms is preferably a structure of formula (16) below. [ka] where the dotted bond indicates the attachment of this group within a ligand or subligand, Y may be the same or different at each occurrence, and CR 1 or N, preferably not more than one occurrence of the symbol Y is N.

[0067] In preferred forms of the ligand or ancillary ligand (L-31) or (L-32), not more than one such condensed group is present. Thus, the ligand or ancillary ligand is preferably of the following formulae (L-33) to (L-38). [ka] wherein X is the same or different at each occurrence and is CR or N, provided that the R radicals together do not form an aromatic or heteroaromatic ring system, and the further symbols have the meanings given above.

[0068] In a preferred embodiment of the invention, in the ligands or ancillary ligands of formulae (L-31) to (L-38), the symbols X, in total, 0, 1 or 2, and Y, if present, are N. More preferably, the symbols X, in total, 0 or 1, and Y, if present, are N.

[0069] Preferred embodiments of formulae (L-33) to (L-38) are structures of the following formulae (L-33a) to (L-38f).

[0070] [ka]

[0071] [ka]

[0072] [ka] wherein the symbols used have the definitions given above, and "o" in formula (1) or (3) indicates the position of attachment to the bridge V, in which case the corresponding R group is absent.

[0073] In a preferred form of the invention, the X group which coordinates to the metal at the ortho position is CR. The R radical which is bonded for coordination to the metal at the ortho position is preferably selected from the group consisting of H, D, F and methyl.

[0074] In a further embodiment of the invention, it is preferred that one of the atoms X is N, provided that the substituent bonded adjacent to this nitrogen atom is an R group which is not hydrogen or deuterium. In this case, the substituent R is preferably CF3, OCF3, an alkyl group having 1 to 10 carbon atoms, in particular a branched or cyclic alkyl group having 3 to 10 carbon atoms, OR 1 (where R 1 is a group selected from an alkyl group having 1 to 10 carbon atoms, in particular a branched or cyclic alkyl group having 3 to 10 carbon atoms, a dialkylamino group having 2 to 10 carbon atoms, or an aryl or heteroaryl group having 5 to 10 aromatic ring atoms. These groups are sterically bulky groups. More preferably, this R radical may also form a ring together with the adjacent R radical.

[0075] In a preferred form of the invention, exactly one of the ligands or subligands L or L' is a ligand or subligand of formula (L-39) below, which coordinates to iridium via two D groups. [ka] where "o" in formula (1) or (3) indicates the position of the bond to the bridge V, in which case the corresponding X is C, and further D is C or N, with the proviso that one D is C and the other D is N; X is identical or different at each occurrence and is CR or N; Z is CR', CR or N, with the proviso that exactly one Z is CR' and the other Z is CR or N; where at most one symbol X or Z per whole ring is N; R' is a group of formula (17) or (18): [ka] where the dotted lines indicate radical attachment; R″ is the same or different at each occurrence and is H, D, F, CN, a straight chain alkyl group having 1 to 10 carbon atoms (wherein one or more hydrogen atoms may be replaced by D or F), a branched or cyclic alkyl group having 3 to 10 carbon atoms (wherein one or more hydrogen atoms may be replaced by D or F), or an alkenyl group having 2 to 10 carbon atoms (wherein one or more hydrogen atoms may be replaced by D or F); at the same time, two adjacent R″ radicals or two R″ radicals on adjacent phenyl groups may together form a ring system; or two R″ on adjacent phenyl groups may together form C(R 1 )2, NR 1 is a group selected from O and S, where the two phenyl rings together with the bridging group are carbazole, fluorene, dibenzofuran or dibenzothiophene, and further R″ is as defined above; n is 0, 1, 2, 3, 4 or 5.

[0076] In the case of ring formation by two substituents R″ on adjacent phenyl groups, the result may be fluorene or phenanthrene or triphenylene. Similarly, as above, two R″ on adjacent phenyl groups together may be NR 1 , O and S, and it is possible for the two phenyl groups together with the bridging group to be a carbazole, dibenzofuran or dibenzothiophene.

[0077] In a preferred embodiment of the invention, X is the same or different at each occurrence and is CR. More preferably, one Z group is CR and the other Z group is CR'. More preferably, in the ligand or subligand of formula (L-39), X is the same or different at each occurrence and is CR, and at the same time, one Z group is CR and the other Z is CR'. The ligand or subligand L or L' preferably has a structure of one of the following formulae (L-39a) or (L-39b), in which the bond to the bridge V for the multipod structure of formula (L-39) is via the position marked "o", and there is no R radical bonded at this position. [ka] wherein the symbols used have the definitions given above, and when the ancillary ligand in formula (1) or (3) is attached to the bridgehead V through the position marked with "o", the R radical is absent.

[0078] More preferably, the ancillary ligand L of formula (L-39) has a structure according to one of the following formulae (L-39a') or (L-39b'), in which the bond to the bridge V for the multipod structure of formula (L-39) is via the position marked "o" and there is no R radical bonded at this position. [ka] Here, the symbols used have the definitions given above.

[0079] The R radical in the ancillary ligand L of formula (L-39) or formulae (L-39a), (L-39b), (L-39a') and (L-39d') is preferably H, D, CN, OR 1 a linear alkyl group having 1 to 6 carbon atoms, preferably having 1, 2 or 3 carbon atoms, or a branched or cyclic alkyl group having 3, 4, 5 or 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, preferably having 2, 3 or 4 carbon atoms (each of which may be selected from the group consisting of one or more R 1 radicals), one or more non-aromatic R1 phenyl groups, optionally substituted by R radicals, where two or more adjacent R radicals may together form a ring system.

[0080] In this case, the substituent R attached to the coordination atom in the ortho position is preferably selected from the group consisting of H, D, F and methyl, more preferably H, D and methyl, in particular H and D.

[0081] Additionally, it is preferred that all substituents R that are ortho to R' are H or D.

[0082] If the R radicals in the ancillary ligand L of formula (L-39) together form a ring system, it is preferably an aliphatic, heteroaliphatic or heteroaromatic ring system. Furthermore, it is preferably a ring formation between two R radicals on two rings of ancillary ligand L or L', preferably forming a phenanthridine or a phenanthridine which may further contain a nitrogen atom. If the R radicals together form a heteroaromatic ring system, this is preferably quinoline, isoquinoline, dibenzofuran, dibenzothiophene and carbazole (each of which may contain one or more R 1 radicals and wherein each carbon atom in dibenzofuran, dibenzothiophene and carbazole may be replaced by N). Particularly preferred are quinoline, isoquinoline, dibenzofuran and azadibenzofuran. Here, the fused structure can be bonded at any possible position. Preferred ancillary ligands L or L' having fused benzo groups are structures of the following formulae (L-39c) to (L-39j), where the bond to the bridge V for the multipod structure of formula (L-39) is via the position specified by "o". [ka] wherein each ligand may be optionally substituted with one or more further R radicals and the fused structure may be one or more R 1Preferably, the further R or R 1 No radicals are present.

[0083] Preferred ancillary ligands L or L' of formula (L-39) bearing a fused benzofuran or azabenzofuran group are structures of formulae (L-39k) to (L-39z) below, in which the bond to the bridge V for the multipod structure of formula (L-39) is via the position specified by "o". [ka] wherein each ligand may be optionally substituted with one or more further R radicals and the fused structure may be one or more R 1 Preferably, the further R or R 1 There are no radicals. Similarly, O in these structures is not S or NR 1 can be replaced by:

[0084] As above, R' is a group of formula (17) or (18), where the two groups differ simply in that the group of formula (17) is attached at the para position to the ligand or subligand L or L', and the group of formula (18) is attached at the meta position.

[0085] In a preferred embodiment of the invention, n=0, 1 or 2, preferably 0 or 1, and most preferably 0.

[0086] In a further preferred form of the invention, both substituents R″ attached at the ortho position to the carbon atom by which the group of formula (17) or (18) is attached to the phenylpyridine ligand are the same or different and are H or D.

[0087] Preferred embodiments of the structure of formula (17) are structures of formulae (17a) to (17h), and preferred embodiments of the structure of formula (18) are structures of formulae (18a) to (18h).

[0088] [ka]

[0089] [ka] Here, E is C(R 1 )2, NR 1 , O or S, and further symbols used have the above definitions. 1 is E=C(R 1 )2, it is preferably an alkyl group, which may be the same or different at each occurrence, having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, more preferably methyl. 1 If R 1 is preferably an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, preferably 6 to 24 aromatic ring atoms, more preferably 6 to 12 aromatic ring atoms, in particular phenyl.

[0090] Preferred substituents R″ on the radicals or preferred forms of formula (17) or (18) are selected from the group consisting of H, D, CN and alkyl radicals having 1 to 4 carbon atoms, more preferably H, D or methyl.

[0091] The ancillary ligand L″ is a bis-bidentate cyclometallated ancillary ligand coordinated to both iridium atoms. In a preferred form of the invention, the ancillary ligand is of formula (19) or (20) below: [ka] where X has the definition given above, the dotted line indicates the bond to V, the * indicates coordination to the iridium atom, and further: D is the same or different at each occurrence and is C or N; Q in formula (19) is a group selected from formulas (Q-1) to (Q-3), and Q in formula (20) is a group selected from formulas (Q-4) to (Q-15), [ka] where the dotted line indicates in each case the bond in formula (19) or (20), the * marks the position at which the group is coordinated to the iridium atom, and X has the definition given above.

[0092] In formulas (Q-1) to (Q-15), preferably no more than two X groups per Q group that are not directly bonded to each other are N, more preferably no more than one X group is N. Most preferably, all X are CR, especially CH, and all R in (Q-1) to (Q-3) and (Q-7) to (Q-9) are H or D, especially H.

[0093] In the compound of formula (20), preferred are groups (Q-4), (Q-5) and (Q-7) to (Q-9).

[0094] In a preferred embodiment of the invention, the ancillary ligand of formula (19) or (20) is coordinated to each of the two iridium atoms with exactly one carbon atom and one nitrogen atom available as a coordinating atom in Q and as a coordinating atom D. Thus, when the Q group represents a group of formula (Q-1), (Q-4), (Q-7), (Q-10) or (Q-13), i.e., when it is coordinated to each of the two iridium atoms via a nitrogen atom, the two D groups are preferably carbon atoms. When the Q group represents a group of formula (Q-2), (Q-5), (Q-8), (Q-11) or (Q-14), i.e., when it is coordinated to each of the two iridium atoms via a carbon atom, the two D groups are preferably nitrogen atoms. When the Q group represents a group of formula (Q-3), (Q-6), (Q-9), (Q-12) or (Q-15), i.e. is coordinated to two iridium atoms via one carbon atom and one nitrogen atom, preferably one of the two D groups is a nitrogen atom and the other D group is a carbon atom, and each iridium atom is coordinated by one carbon atom and one nitrogen atom.

[0095] In a further preferred embodiment of the invention, the symbol X shown in formula (19) or (20) is, identically or differently on each occurrence, CR, in particular CH or CD.

[0096] When L' is a non-cyclometallated ligand or ancillary ligand, preferred forms of L' are acetylacetonate or a derivative thereof, picolinic acid or a derivative thereof, pyrazolyl borate or hydroxyquinoline or a derivative thereof.

[0097] The complexes of formula (1) and (3) are hexadentate or dodecadentate ligands, in which the three ancillary ligands L and L' of formula (1) are covalently linked to each other by one bridging unit V, and the three ancillary ligands L' and L'' of formula (3) are covalently linked to each other by two bridging units V.

[0098] In a preferred form of the invention, the bridging unit V is a group of formula (21) below, where the dotted bonds indicate the position of the ancillary ligands L or L' in formula (1) and L'' in formula (3). [ka] Where: X 1 is the same or different at each occurrence and is CR or N; X 2 is the same or different at each occurrence and is CR or N; A is the same or different at each occurrence and is CR2-CR2, CR2-O, CR2-NR, C(=O)-O, C(=O)-NR or a group of formula (22): [ka] where in each case the dotted line indicates the point of attachment of the bidentate ancillary ligand L or L' in formula (1) or L' and L'' in formula (3) to this structure, and the * indicates the point of attachment to the central trivalent aryl or heteroaryl group of the unit of formula (21).

[0099] X 2 Preferred substituents for the group of formula (22) when =CR are selected from the R substituents described above.

[0100] In a preferred embodiment of the invention, A is identical or different at each occurrence and is CR2-CR2 or a group of formula (22), preferably in the following form: - all three A groups are the same group of formula (22); - two A groups are identical groups of formula (22) and the third A group is CR2-CR2; - one A group is identical groups of formula (22) and the other two A groups are identical CR2-CR2 groups; or - all three A groups are identical CR2-CR2 groups.

[0101] Here, "the same group of formula (22)" means that all of these groups have the same basic skeleton and the same substituents. Furthermore, "the same CR2-CR2 group" means that all of these groups have the same substituents.

[0102] When A is CR2-CR2, R is preferably the same or different at each occurrence and is H or D, more preferably H.

[0103] The group of formula (22) is an aromatic or heteroaromatic 6-membered ring. In a preferred embodiment of the invention, the group of formula (22) contains not more than one heteroatom in the aryl or heteroaryl group. This does not mean that the substituents attached to this group cannot contain heteroatoms. Furthermore, this definition does not mean that the ring formation by the substituents does not form a fused aromatic or heteroaromatic structure (e.g. naphthalene, benzimidazole, etc.). The group of formula (22) is preferably selected from benzene, pyridine, pyrimidine, pyrazine and pyridazine, especially benzene.

[0104] Preferred embodiments of the group of formula (22) are structures of the following formulae (22a) to (22h). [ka] Here, the symbols used have the definitions given above.

[0105] Particularly preferred are the optionally substituted 6-membered aromatic and 6-membered heteroaromatic rings of the formulae (22a) to (22h). Very preferred is ortho-phenylene, i.e. the group of formula (22a).

[0106] At the same time, as described above for the substituents, adjacent substituents may together form a ring system to form a fused structure containing fused aryl and heteroaryl groups (e.g., naphthalene, quinoline, benzimidazole, carbazole, dibenzofuran, or dibenzothiophene).

[0107] Preferred forms of the bridgehead V, that is, the structure of formula (21), are described below. Preferred forms of the group of formula (21) are the structures of the following formulae (23) to (26). [ka] Here, the symbols used have the definitions given above.

[0108] More preferably, all substituents R in the central ring of formulae (23) to (26) are H, and thus the structures are preferably selected from formulae (23a) to (26a). [ka] Here, the symbols used have the definitions given above.

[0109] More preferably, the groups of formulae (23) to (26) are selected from the structures of formulae (23b) to (26b) below. [ka] wherein R is the same or different at each occurrence and is H or D, preferably H.

[0110] Further examples of suitable bridgeheads V are the structures shown below. [ka]

[0111] A description of preferred substituents that may be present on the ancillary ligands L, L', and L'' above, as well as on the divalent arylene or heteroarylene group of the structure of formula (21), i.e., the structure of formula (22), follows.

[0112] In one aspect of the invention, the metal complex comprises two R substituents or two R groups bonded to adjacent carbon atoms which together form an alicyclic ring according to one of the formulae shown below: 1 In this case, the two R substituents forming the alicyclic ring may be present in the bridge of formula (21) and / or in one or more bidentate ancillary ligands or ligands. The alicyclic ring formed by two R substituents together forming a ring is preferably represented by one of the following formulae (27) to (33): [ka] Here, R 1 and R 2 has the above definition, the dotted bond indicates the attachment of two carbon atoms in the ligand, and further: G has 1, 2 or 3 carbon atoms and one or more R 2 an alkylene group optionally substituted by a radical, -CR 2 =CR 2 - or 5 or 6 aromatic ring atoms and one or more R 2 an ortho-linked arylene or heteroarylene group optionally substituted by a radical; R 3 are the same or different for each occurrence, H, F, OR 2 , a linear alkyl group having 1 to 10 carbon atoms, a branched or cyclic alkyl group having 3 to 10 carbon atoms, where the alkyl group is in each case composed of one or more R 2 one or more non-adjacent CH groups may be replaced by R 2C=CR 2 , C≡C, Si(R 2 )2, C=O, NR 2 , O, S or CONR 2 or 5 or 6 aromatic ring atoms, in each case one or more R 2 an aryl or heteroaryl group, optionally substituted by a radical; and at the same time, two R 3 The radicals together may form an aliphatic or aromatic ring system, forming a spiro system; further, R 3 is adjacent to R or R 1 The radicals may also form an aliphatic ring system.

[0113] In the structures of formulas (27) to (33) above, a double bond is formed in a formal sense between two carbon atoms. This is a simplification of the chemical structure in which two carbon atoms are incorporated into an aromatic or heteroaromatic ring system, and the bond between these two carbon atoms is formally between the bond order of a double bond and the bond order of a single bond.

[0114] Preferred forms of the radicals of formulae (27) to (33) can be found in applications WO2014 / 023377, WO2015 / 104045 and WO2015 / 117718.

[0115] When R radicals are attached in a bidentate or ancillary ligand L, L' or L'', or in a divalent arylene or heteroarylene group of formula (22) attached in formula (21) or in a preferred form, these R radicals are the same or different at each occurrence and are preferably H, D, F, Br, I, N(R 1 )2, CN, Si(R 1 )3, B(OR 1 )2, C(=O)R 1 , a linear alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a branched or cyclic alkyl group having 3 to 10 carbon atoms (wherein the alkyl or alkoxy group is in each case composed of one or more R1 or 6 to 24 aromatic ring atoms, in each case one or more of R 1 and R is selected from the group consisting of an aromatic or heteroaromatic ring system, optionally substituted by an aryl group; and at the same time, two adjacent R radicals together or R is selected from the group consisting of an aromatic or heteroaromatic ring system, optionally substituted by an aryl group; 1 Together with R, they may form a monocyclic or polycyclic, aliphatic or aromatic ring system. More preferably, these R radicals are the same or different at each occurrence and are selected from H, D, F, N(R 1 2, a linear alkyl group having 1 to 6 carbon atoms, a branched or cyclic alkyl group having 3 to 10 carbon atoms, in which one or more hydrogen atoms may be replaced by D or F, or a cyclic alkyl group having 6 to 18 aromatic ring atoms, in particular 6 to 13 aromatic ring atoms, and containing one or more R 1 and R is selected from the group consisting of an aromatic or heteroaromatic ring system, optionally substituted by an aryl group; and at the same time, two adjacent R radicals together or R is selected from the group consisting of an aromatic or heteroaromatic ring system, optionally substituted by an aryl group; 1 Together with the radicals they may form a mono- or polycyclic, aliphatic or aromatic ring system.

[0116] Preferred R 1 The radicals may be the same or different at each occurrence and are H, D, F, N(R 2 ) 2, CN, a linear alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a branched or cyclic alkyl group having 3 to 10 carbon atoms (wherein the alkyl group is in each case one or more R 2 or having 6 to 24 aromatic ring atoms and one or more R 2 an aromatic or heteroaromatic ring system, optionally substituted by a radical; at the same time, two or more adjacent R 1 The radicals together may form a monocyclic or polycyclic aliphatic ring system. Particularly preferred R 1The radicals may be the same or different at each occurrence and may be H, F, CN, a straight chain alkyl group having 1 to 5 carbon atoms, a branched or cyclic alkyl group having 3 to 5 carbon atoms, each of which may be represented by one or more radicals R 2 or having 6 to 18 aromatic ring atoms, particularly 6 to 13 aromatic ring atoms, and one or more R 2 an aromatic or heteroaromatic ring system, optionally substituted by a radical; at the same time, two or more adjacent R 1 The radicals may together form a mono- or polycyclic, aliphatic ring system.

[0117] Preferred R 2 The radicals are identical or different at each occurrence and are H, F, or an aliphatic hydrocarbyl radical having 1 to 5 carbon atoms, or an aromatic hydrocarbyl radical having 6 to 12 carbon atoms, and at the same time, two or more R 2 The substituents together may form a mono- or polycyclic, aliphatic ring system.

[0118] The preferred aspects described above may be combined with one another if desired within the scope of claim 1. In a particularly preferred embodiment of the invention, the preferred aspects described above are applied simultaneously.

[0119] In general, the method of the present invention can provide all cyclometallated iridium complexes used by the prior art in organic electroluminescent devices.For example, the complexes described in the applications WO00 / 70655, WO2001 / 41512, WO2002 / 02714, WO2002 / 15645, EP1191613, EP1191612, EP1191614, WO05 / 033244, WO05 / 019373, US2005 / 0258742, WO2009 / 146770, WO2010 / 015307, WO2010 / 0314 85, WO2010 / 054731, WO2010 / 054728, WO2010 / 086089, WO2010 / 099852, WO2010 / 102709, WO2011 / 032626, W O2011 / 066898, WO2011 / 157339, WO2012 / 007086, WO2014 / 008982, WO2014 / 023377, WO2014 / 094961, WO201 4 / 094960, WO2015 / 036074, WO2015 / 104045, WO2015 / 117718, WO2016 / 015815, WO2016 / 124304, WO2017 / 03 2439, WO2018 / 011186, WO2018 / 001990, WO2018 / 019687, WO2018 / 019688, WO2018 / 041769, WO2018 / 054798 , WO2018 / 069196, WO2018 / 069197, WO2018 / 069273, WO2018 / 178001, WO2018 / 177981, WO2019 / 020538, WO2019 / 115423, WO2019 / 158453, WO2019 / 179909 and US2020 / 0048290, and the unpublished publication EP19156381.6.

[0120] In general, all ligands which are usually used in cyclometallated complexes used in organic electroluminescent devices can be used in the method according to the invention.

[0121] Useful iridium compounds that may be used as reactants in the method of the present invention include a variety of compounds. Preferred iridium reactants are iridium halides, particularly iridium chloride, iridium carboxylates, particularly iridium acetate, iridium-COD complexes, iridium ketoketonates, and the compounds described below.

[0122] Preferred iridium compounds which may be used as reactants in the process of the present invention are compounds of formulae (34) to (39) below. [ka] where R, CyC and CyD have the definitions given above, and other symbols used are as follows: Hal is identical or different at each occurrence and is F, Cl, Br or I; Kat is the same or different at each occurrence and is an alkali metal cation, an ammonium cation, a tetraalkylammonium cation having 4 to 40 carbon atoms, or a tetraalkylphosphonium cation having 4 to 40 carbon atoms; z is 0 to 100; y is between 0 and 100.

[0123] Also suitable are COD-iridium(I) compounds such as [(COD)IrCl]2 (CAS[12112-67-3]) or (COD)Ir(Ind) (CAS[102525-11-1]), where COD denotes cyclooctadiene and Ind denotes indenyl.

[0124] Iridium halide hydrates of formula (34), in particular iridium chloride hydrates, are not defined compounds since they are hygroscopic compounds that may contain varying amounts of HCl and / or water, where the water content of the batch is typically reported by the iridium content. In the sense of the present invention, the term "iridium halide" or "iridium halide hydrate" includes all these compounds, regardless of the amount of water and hydrogen halide present.

[0125] Iridium carboxylates of formula (36) (e.g., iridium acetate) are also not completely stoichiometric or defined compounds, and useful compounds include various carboxylates that may contain varying amounts of acetate, water, hydroxide, such as compounds with CAS [37598-27-9], [126310-98-3], or [52705-52-9]. In the sense of the present invention, the term "iridium carboxylate" includes all these compounds, regardless of their exact composition.

[0126] R in formulas (36), (37) and (38) is preferably an alkyl group having 1 to 10 carbon atoms or an aromatic ring atom having 5 to 12 and one or more R 1 More preferably, R in formulae (36), (37) and (38) is an alkyl group preferably having 1 to 5 carbon atoms, in particular methyl or tert-butyl.

[0127] Preferred compounds of formula (34) are those in which the index z is 1 to 10, more preferably 2 to 4. Preferred compounds of formula (34) are also those in which the index y is 0 to 10, more preferably 0 to 3. More preferably, z=2 to 4 and y=0 to 3 at the same time.

[0128] Preferred compounds of formula (35) are those in which the subscript z is 0 to 10, more preferably 0 to 3. Preferred compounds of formula (35) are also those in which the subscript y is 0 to 10, more preferably 0 to 3, and even more preferably 0. More preferably, z=0 to 3 and y=0 to 3 at the same time.

[0129] The subscripts z and y do not have to be integers because the reactants may contain non-stoichiometric amounts of water and hydrogen halides. The water content will vary from batch to batch, especially since hygroscopic metal salts are included.

[0130] Preferred compounds of formulae (34), (35), (38) and (39) are also those in which the symbol Hal, which may be the same or different on each occurrence, is Cl or Br, more preferably Cl.

[0131] The process is carried out according to the invention in an anhydrous medium in the presence of at least one carboxylic acid. A carboxylic acid is an organic compound having one or more carboxy groups (-COOH). Suitable carboxylic acids are both those that are liquid at room temperature and those that are solid at room temperature but dissolve under the reaction conditions.

[0132] A preferred embodiment of the present invention is a compound of formula R 4 Monocarboxylic acids of the formula -COOH, or HOOC-R 5 -COOH, where R 4 is a linear alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl group is in each case one or more R 1 or having 2 to 20 carbon atoms and one or more R 1 an alkenyl or alkynyl group having 5 to 40 aromatic ring atoms, optionally substituted by a radical, 1 an aromatic or heteroaromatic ring system or a ring system having 5 to 20 aromatic ring atoms, optionally substituted by radicals, in each case one or more R 1 R is selected from the group consisting of aralkyl and heteroaralkyl groups, optionally substituted by radicals. 5 is a linear alkylene group having 1 to 20 carbon atoms or a branched or cyclic alkylene group having 3 to 20 carbon atoms, where the alkylene group is in each case one or more R 1 radicals), having 2 to 20 carbon atoms and one or more R 1 an alkenyl or alkynyl group having 5 to 40 aromatic ring atoms, and in each case one or more non-aromatic R1 a divalent aromatic or heteroaromatic ring system, or a divalent ring system having 5 to 20 aromatic ring atoms, optionally substituted by radicals, in each case one or more R 1 R is selected from the group consisting of divalent aralkyl or heteroaralkyl groups, optionally substituted by radicals. 1 has the definition given above.

[0133] In a preferred embodiment of the invention, R 4 is selected from the group consisting of straight-chain alkyl groups having 1 to 10 carbon atoms, more preferably having 1, 2, 3 or 4 carbon atoms, or branched or cyclic alkyl groups having 3 to 10 carbon atoms, more preferably having 3, 4, 5 or 6 carbon atoms, where the alkyl groups may in each case be substituted by a phenyl group, or aromatic or heteroaromatic ring systems having 6 to 12 aromatic ring atoms, preferably a phenyl group which may in each case be substituted by one or more alkyl groups having 1 to 4 carbon atoms, or an aralkyl group having 6 to 12 aromatic ring atoms.

[0134] In a further preferred embodiment of the invention, R 5 is selected from the group consisting of a straight-chain alkylene group having 1 to 10 carbon atoms, more preferably having 1, 2, 3 or 4 carbon atoms, a branched or cyclic alkylene group having 3 to 10 carbon atoms, more preferably having 3, 4, 5 or 6 carbon atoms, where the alkylene group may in each case be substituted by a phenyl group, or a divalent aromatic or heteroaromatic ring system having 6 to 12 aromatic ring atoms, preferably a phenylene group which may in each case be substituted by one or more alkyl groups having 1 to 4 carbon atoms, or an aralkyl group having 6 to 12 aromatic carbon atoms.

[0135] Preferred carboxylic acids are acetic acid, propionic acid, pivalic acid, benzoic acid, phenylacetic acid, adipic acid, and mixtures thereof. Particularly preferred are acetic acid, pivalic acid, benzoic acid, salicylic acid, or phenylacetic acid, and mixtures thereof.

[0136] The ligand may be poorly soluble, for example, in glacial acetic acid. In this case, the use or addition of a carboxylic acid having an aromatic moiety, such as benzoic acid, salicylic acid or phenylacetic acid, is advantageous.

[0137] Also suitable are dicarboxylic acids, such as, for example, maleic acid, fumaric acid, malonic acid, phthalic acid, isophthalic acid, terephthalic acid.Further suitable carboxylic acids are, in particular, α-, β-, γ- or ε-amino acids, such as glycine, alanine, phenylalanine or ε-aminocaproic acid, and hydroxycarboxylic acids, in particular α-, β-, γ- or ε-hydroxycarboxylic acids, such as malic acid, D-, L- or meso-tartaric acid, citric acid, glycolic acid, D- or L-mandelic acid or lactic acid.

[0138] In one embodiment of the present invention, a carboxylic acid or a mixture of two or more carboxylic acids is used as a single solvent. In a further embodiment of the present invention, the solvent used is a mixture of one or more carboxylic acids and one or more inert organic solvents (e.g., dioxane, toluene, anisole, xylene, mesitylene or various ethylene glycol ethers). Here, "inert" means that the solvent does not react with the carboxylic acid used and does not have any acidic protons, especially hydroxy groups. Inert solvents are characterized by a pKa>15. The use of an organic solvent is useful to improve the solubility of the ligand. Furthermore, the use of an organic solvent simplifies the reaction system, especially on a production scale.

[0139] The amount of carboxylic acid used is preferably 1 to 100 g per mmol of iridium reactant, more preferably 10 to 50 g per mmol of iridium reactant.

[0140] It may be preferred to add a further additive to the reaction mixture depending on the iridium reactant.

[0141] It is preferable to add a water scavenger, especially when the iridium reactant used is a hydrate (e.g. iridium chloride hydrate). In the sense of the present invention, a water scavenger is a compound that chemically reacts with water under reaction conditions, thereby removing water from the reaction mixture. Here, it is preferable that the water scavenger is selected so that it chemically reacts with water under reaction conditions sufficient to react, where the water content of the reaction mixture (determined, for example, by Karl Fischer titration, as described in Chemie, unserer Zeit 2000, No. 3) is less than 10 ppm. The skilled person generally knows which compounds react with water and can remove water from the reaction mixture.

[0142] Suitable water scavengers are, for example, carboxylic acid anhydrides, carbonyl halides, especially carbonyl chlorides, trialkyl orthocarboxylates or carbodiimides, but also inorganic compounds which react with water, such as phosphorus pentoxide (PO 10 ), thionyl chloride, or phosphoryl chloride). Examples of suitable carboxylic acid anhydrides and carbonyl halides are those which correspond to the carboxylic acid used in the reaction mixture, i.e., for example, acetic anhydride or acetyl chloride when acetic acid is used, pivalic anhydride or pivaloyl chloride when pivalic acid is used, benzoic anhydride or benzoyl chloride when benzoic acid is used, phenylacetic anhydride or phenylacetic chloride when phenylacetic acid is used, etc. A further suitable carbonyl chloride is oxalyl chloride. For example, it is also possible to use acetic anhydride or acetyl chloride simultaneously with a high-melting or high-boiling carboxylic acid. Here, it is preferred to distill off the acetic acid formed during the reaction. Examples of suitable trialkyl orthocarboxylates are trimethyl orthoformate and triethyl orthoacetate. An example of a suitable carbodiimide is dicyclohexylcarbodiimide (DCI). All these compounds are water scavengers in the sense of the present invention.

[0143] The amount of water scavenger is preferably 3 to 30 equivalents, more preferably 5 to 20 equivalents, and most preferably 10 to 20 equivalents, where equivalents are based on the molar amount of iridium reactant used.

[0144] In the case of anhydrous iridium reactants, there is no additional benefit from the addition of a water scavenger.

[0145] The addition of a salt is also beneficial, especially when a halide is used as an iridium reactant, for example an iridium halide hydrate or [(COD)IrCl]2. The salt is considered to act as a halide scavenger, and in the sense of the present invention, a halide scavenger is a compound which forms a sparingly soluble salt with the halide of the iridium reactant in the reaction medium. However, in contrast to the prior art, the addition of a silver salt is not required, since many salts are sparingly soluble in carboxylic acid salts and it is possible to avoid the formation of silver halides which are difficult to separate. Suitable halide scavenger are, for example, alkali metal, alkaline earth metal, ammonium or zinc salts, in particular the corresponding salts of the carboxylic acid used in the reaction medium. Furthermore, even if a high-melting or high-boiling carboxylic acid is used, the corresponding acetate salts are also suitable, in which case the acetic acid formed is preferably distilled off during the reaction. Suitable alkali metal salts are preferably lithium, sodium or potassium salts, preferably sodium or potassium salts, more preferably potassium salts. Thus, it is preferred not only to use potassium acetate when acetic acid is used, but also to use potassium pivalate when pivalic acid is used, potassium benzoate when benzoic acid is used, and potassium salicylate when salicylic acid is used, all of which are halide scavengers within the meaning of the present invention.

[0146] The amount of added salt used as a halide scavenger is preferably 10 to 100 equivalents, more preferably 10 to 50 equivalents, and most preferably 20 to 40 equivalents, where equivalents are based on the molar amount of iridium reactant used.

[0147] In the case of halide-free iridium reactants, there is no additional benefit from the addition of a halide scavenger.

[0148] The reaction is preferably carried out at a temperature range of room temperature to 250°C, preferably 60 to 230°C, more preferably 80 to 200°C, even more preferably 100 to 180°C, and particularly preferably 120 to 160°C. Here, this temperature is the jacket temperature of the reaction vessel. The reaction temperature also depends on the iridium reactant used. For example, in the case of a reactive iridium reactant, such as (COD)Ir(Ind), a reaction temperature of less than 100°C is sufficient to obtain very good yields, whereas, for example, in the case of using iridium chloride hydrate, a reaction temperature in the range of 120 to 160°C achieves much better yields.

[0149] In a preferred embodiment of the invention, the reaction is carried out under a protective gas atmosphere, in particular nitrogen or argon.

[0150] In one embodiment of the invention, the reaction is carried out under reflux at normal pressure. In a further embodiment, the reaction is carried out in a closed system, such as a closed ampoule or autoclave, under reflux, where the pressure corresponds to the vapor pressure above the solution.

[0151] The preferred molar ratio of iridium to ligand used in the reaction medium depends on the iridium reactant used and the ligand used. When a tripodal hexadentate ligand is used in the complex of formula (1), a ratio of Ir to ligand of 1:0.9 to 1:5 is preferred, in particular a ratio of 1:1 to 1:1.05. In the complex of formula (2), the ratio of Ir to ligand is preferably 1:1 to 1:20, more preferably 1:3 to 1:15, most preferably 1:10 to 1:13. In the complex of formula (3), the ratio of Ir to ligand is preferably 1.5:1 to 10:1, preferably 1.9:1 to 3:1, most preferably 1.9:1 to 2:1.

[0152] The reaction is carried out preferably for 1 to 1000 hours, more preferably for 5 to 500 hours, and most preferably for 10 to 200 hours.

[0153] When halogen-containing iridium reactants are used, it is further preferred that the reaction vessel used is not a steel tank, but rather a reaction vessel made, for example, of glass, enamel or Teflon.

[0154] Further acceleration of the reaction can be achieved by using microwave irradiation: methods by which cyclometallation reactions are typically carried out in microwaves are disclosed, for example, in WO 2004 / 108738.

[0155] The work-up of the reaction mixture is simple in the process of the present invention, since the cyclometallated iridium compound usually partially or completely precipitates during the reaction. This can be accomplished by precipitation using a solvent that does not require the iridium compound, such as an alcohol (e.g. ethanol), water, or a mixture of alcohol and water. In addition, it is also useful to add an organic solvent (e.g. toluene, xylene or dioxane) to dissolve excess ligands from the product. The product is then separated and purified by filtration and washing with a solvent that does not require the ligand (e.g. water, an alcohol (e.g. ethanol), or a mixture of alcohol and water). If necessary, further purification can be performed by methods commonly used for iridium complexes, such as recrystallization, chromatography, thermal extraction, sublimation and / or heat treatment.

[0156] The complex obtained by the method of the present invention is a chiral compound, typically obtained in racemic form. It is also possible to synthesize enantiomerically enriched or enantiomerically pure complexes by using chiral enantiomerically pure carboxylic acids. A suitable example for this purpose is the use of α-amino carboxylic acids (such as alanine, phenylalanine, and a variety of them are available). Also suitable are hydroxy carboxylic acids (such as maleic acid or tartaric acid).

[0157] The method according to the invention offers the following advantages over the prior art: 1. The process of the present invention makes it possible to obtain cyclometallated iridium complexes, in particular tris-cyclometallated iridium complexes, in one step and in very high yields from other iridium reactants, also from readily available iridium halides, whereas many prior art processes start from more complex reactants (e.g. iridium ketoketonate complexes or chloro-bridged dimeric iridium complexes) and / or have low yields. 2. The carboxylic acids used in the process of the present invention may be used in standard manner in organic manufacturing without the need for special safety precautions beyond those of normal organic manufacturing. 3. Process temperatures up to 190 ° C and pressures up to 6 bar are within the usual range in organic production and no special technical measures are required for this purpose. This applies in particular to the reaction regime in the preferred region of about 120 ° C and atmosphere under reflux. 4. Heating and cooling times can be performed without difficulty in normal organic manufacturing and are not process critical. 5. Post-treatment includes typical simple process steps such as filtration, centrifugation, washing and / or drying, as well as purification by recrystallization, chromatography, sublimation and / or heat treatment. 6. No formation of metallic iridium in the form of iridium mirror or iridium black is observed. More specifically, no formation of pyrophoric elemental iridium is observed, which is a major improvement in reaction safety.

[0158] More specifically, the advantages detailed above make the method of the present invention very well suited for the preparation of cyclometallated iridium complexes not only on a laboratory scale but also on a manufacturing scale.

[0159] The present invention is explained in more detail by the following examples, which are not intended to limit the present invention. Those skilled in the art of organic and organometallic synthesis can carry out the reaction of the present invention in other systems without further inventive effort. In particular, the method can be carried out in systems of different substitution or systems containing other aryl or heteroaryl groups as ligands instead of phenyl or pyridine without further inventive effort. Similarly, those skilled in the art can carry out the method of the present invention by adding carboxylic acids, other water scavengers and / or other bases. EXAMPLES

[0160] Working Example: The following syntheses are carried out in dry solvents under a protective gas atmosphere unless otherwise stated. Metal complexes are further treated with the exclusion of light or under yellow light. Solvents and reagents are available, for example, from Sigma-Aldrich or ABCR. The respective numbers in square brackets or the numbers given for the individual compounds refer to the CAS numbers of the compounds known from the literature. In the case of compounds which may have multiple enantiomers, diastereomers or tautomers, they are indicated in a representative manner.

[0161] 1) General procedure A mixture of tripodal hexadentate ligand, iridium reactant and reaction medium R, and, where appropriate, additive A (desiccant, water scavenger) and additive B (carboxylate, used as halide scavenger), is first placed in a sealable pressure-resistant reaction vessel (e.g., a crimp-neck bottle with a septum cap) under argon atmosphere and heated to a specific temperature (=heat to block temperature) in a heating block. Samples are taken at specific times, 1 Analyzed by H NMR spectroscopy and / or HPLC. 1 For H NMR spectroscopy analysis, two drops of the reaction mixture are diluted with 0.75 ml of DMSO-D6, the mixture is heated until a clear solution is obtained, and then analyzed as usual. The spectrum of the reaction mixture is then compared with that of the corresponding ligand and complex in DMSO-D6 and quantified by integration. The error of the method is estimated to be ±5%. HPLC is performed in the standard manner (HPLC column: Chromolith-Performance RP-18e, 100-4.6 mm, gradient: water-acetonitrile, detection 254 nm). Conversions reported are based on the area % of the ligand and complex peaks. The experiments specified below are performed with a molar amount of 1 eq = 100 μmol.

[0162] The results are shown in Table 1. Each heading indicates which parameter was changed. Abbreviations are explained below the table.

[0163] [Table 1-1]

[0164] [Table 1-2]

[0165] [Table 1-3]

[0166] [Table 1-4]

[0167] 1) Δ, Δ- / Λ, Λ-&Δ, Λ-diastereomer mixture, approximately 1:1 2) Addition of 100 eq alanine for chiral induction, Δ, Δ- / Λ, Λ-&Δ, Λ-diastereomer mixture ca. 1:4 Abbreviation: HOAc: Acetic anhydride, glacial acetic acid [64-19-7] HOPiv: Pivalic acid [75-98-9] HOBnz: Benzoic acid [65-85-0] HOPhe: Phenylacetic acid [103-82-2] Ac2O: Acetic anhydride [108-24-7] Pivalic anhydride [1538-75-6] Bnz2O: Benzoic anhydride [93-97-0] AcCl: Acetyl chloride [75-36-5] TMOF: Trimethyl orthoformate [149-73-5] TEOA: Triethyl orthoacetate [78-39-7] P4O 10 :Tetraphosphorus decaoxide [1314-56-3] LiOAc: Lithium acetate, anhydrous [546-89-4] NaOAc: Sodium acetate, anhydrous [127-09-3] KOAc: Potassium acetate, anhydrous [127-08-2] NH4OAc: Ammonium acetate [631-61-8] Zn(OAc)2: Zinc acetate, anhydrous [557-34-6] Potassium pivalate, anhydrous [19455-23-3] KOBnz: Potassium benzoate, anhydrous [582-25-2] L-alanine: L-alanine [56-41-7] IrCl3xH2O: iridium trichloride hydrate, within the meaning of the present invention, a generic name for the compounds shown below, stoichiometrically adjusted depending on the Ir content of the compound used: IrCl3x3H2O:[13569-57-8] IrCl3xXH2O:[14996-61-3] IrCl3x4H2O:[16938-21-9] IrCl3x1H2O:[1542203-90-6] IrCl3x2H2O:[1593479-74-3] IrCl3xHClxH2O: [717927-65-6] Ir(OAc)3: Iridium acetate, within the meaning of the present invention, a general term for the compounds shown below, stoichiometrically adjusted depending on the Ir content of the compound used: Ir(OAc) X :[37598-27-9] [Ir3C 12 H 24 O 16 ]CH3O2:[52705-52-8][Ir(COD)Cl)2:Cyclo-1,5-octadienyl iridium(I) chloride dimer[12112-67-3] (Ind)Ir(COD): (1,5-cyclooctadiene)(η5-indenyl)iridium(I) [102525-11-1] AP: In a closed reaction vessel at a given temperature and under the autogenous pressure of the reaction mixture VA: Crimp neck bottle blanketed with argon for laboratory, for atmosphere; Temperature number: temperature measured in the reaction mixture

[0168] Performance of the method on a preparative scale using the example of L1: [ka] A: in glacial acetic acid with acetic anhydride and potassium acetate An autoclave with a Teflon insert, stirred under argon, is charged with 9.18 g (10 mmol) of ligand L1, 3.53 g (10 mmol) of IrCl3x3H2O, 29.45 g (300 mmol) of potassium acetate, anhydrous, 300 ml of glacial acetic acid and 9.47 ml (100 mmol) of acetic anhydride, sealed and heated with good stirring at 160 ° C for 48 h (pressure: 4.3 bar). After cooling, the yellow suspension is poured into 1000 ml of demineralized water with stirring and the yellow solid is filtered with suction, washed three times with 200 ml of water each time and twice with 50 ml of ethanol each time and dried under reduced pressure. The solid is suspended in 300 ml of warm dichloromethane (DCM) for 1 h and chromatographed on 300 g of silica gel 60 (Merck). The main yellow fraction (Rf ~0.9) is selected and the DCM is evaporated on a rotary evaporator at standard pressure in a water bath at 50 °C, continuously replacing the volume of evaporated DCM by the addition of EtOH. When the DCM evaporation is complete, the mixture is concentrated under reduced pressure to a volume of about 100 ml, the yellow solid is filtered through a double-ended frit, and the residue is washed twice with 50 ml each of ethanol, first dried with an argon stream, then dried under reduced pressure (p ~10 -3 mbar, T~100 °C). Yield: 10.19 g (9.20 mmol); 92% of theory; Purity: >99.5% 1 By H NMR and HPLC. The product thus obtained is further purified by thermal extraction and fractional sublimation as disclosed in WO2016 / 124304.

[0169] B: In pivalic acid with pivalic anhydride and potassium pivalate Procedure as described in A) except using pivalic acid instead of acetic acid, pivalic anhydride instead of acetic anhydride, and potassium pivalate instead of potassium acetate, and carrying out the reaction in a 2 L four-neck round-bottom flask with precision glass stirrer, reflux condenser and argon blanket. Internal temperature ∼165°C. Yield: 10.44 g (9.43 mmol); 94% of theory; Purity: >99.5%. 1 By H NMR and HPLC.

[0170] C: In pivalic acid with acetic anhydride and potassium acetate Procedure as described in B) except that acetic anhydride is used instead of pivalic anhydride and potassium acetate is used instead of potassium pivalate, and the reaction is carried out in a 2 L four-neck round-bottom flask with precision glass stirrer, reflux condenser and argon blanket. Acetic acid collected in the water separator is discarded from time to time. Internal temperature ∼155°C. Yield: 10.51 g (9.50 mmol); 95% of theory; Purity: >99.5%. 1 By H NMR and HPLC.

[0171] D: In benzoic acid with benzoic anhydride and potassium benzoate Procedure as described in A) except that benzoic acid is used instead of acetic acid, benzoic anhydride instead of acetic anhydride, and potassium benzoate instead of potassium acetate, and the reaction is carried out in a 2 L four-neck round-bottom flask with precision glass stirrer, reflux condenser and argon blanket. Internal temperature .about.168°C. For workup, the warm, still liquid reaction mixture is poured into water. Yield: 10.51 g (9.49 mmol); 95% of theory; Purity: >99.5%. 1 By H NMR and HPLC.

[0172] In phenylacetic acid with acetic anhydride and potassium acetate Procedure as described in C) using phenylacetic acid instead of pivalic acid. Internal temperature ∼152 °C. For workup the warm, still liquid reaction mixture is poured into water. Yield: 10.84 g (9.80 mmol); 98% of theory; Purity: >99.5%1 By H NMR and HPLC.

[0173] Ir(OAc)3 in salicylic acid / mesitylene A 500 ml four-neck round-bottom flask equipped with a precision glass stirrer, a water separator (10 ml tank), a reflux condenser and an argon blanket is charged with 9.18 g (10 mmol) of the ligand L1, 3.69 g (10 mmol) of iridium (III) acetate Ir(OAc)3, 40 g of salicylic acid and 40 ml of mesitylene under argon atmosphere and heated under reflux for 22 hours (internal temperature about 158 ​​° C). The initial blue solution becomes a yellow suspension over time; some acetic acid is also initially separated and discarded. After 22 hours, the mixture is cooled to 90 ° C, 200 ml of ethanol is carefully added dropwise, the mixture is cooled to 40 ° C with stirring, and the yellow solid is suction filtered, washed three times with 30 ml of methanol each and dried under reduced pressure. Further purification is disclosed in A. Yield: 10.86 g (9.20 mmol); 98% of theory; Purity: >99.5% 1 By H NMR and HPLC. The product thus obtained is further purified by thermal extraction and fractional sublimation as disclosed in WO2016 / 124304.

[0174] Besides mesitylene, anisole can also be used.

[0175] Ligand: Table 2 shows the ligands used.

[0176] [Table 2-1]

[0177] [Table 2-2]

[0178] [Table 2-3]

Claims

1. 1. A process for preparing a cyclometallated iridium complex by reacting an iridium compound with one or more ligands which coordinate to said iridium under cyclometallation, comprising the steps of:

4. A process characterized in that the process is carried out in an anhydrous medium in the presence of at least one carboxylic acid.

2. 2. The method of claim 1, wherein the cyclometallated iridium complex has the structure of formula (1), (2) or (3). 【Chemistry 1】 (where: L is the same or different at each occurrence and is a bidentate cyclometallated ligand in formula (2), or a bidentate cyclometallated ancillary ligand in formulas (1) and (3); L' is the same or different at each occurrence and is a bidentate ligand in formula (2) or a bidentate ancillary ligand in formulas (1) and (3); L″ is a bisbidentate cyclometallated ancillary ligand coordinated to both iridium atoms; V is the same or different at each occurrence and is a bridging unit which links the ancillary ligands L and L′ together to form a tripodal hexadentate ligand in formula (1) and which links the ancillary ligands L and L′ together to form an overall dodecadentate ligand in formula (3).

3. 3. The method of claim 1 or 2, wherein the cyclometallated iridium complex has a structure of one of formulas (1a), (2a) or (3a): 【Chemistry 2】 (wherein the symbols used have the definitions set out in claim 2)

4. 4. The method according to claim 1, wherein the ligand or ancillary ligand is coordinated to iridium via one carbon atom and one nitrogen atom, or via two carbon atoms.

5. The method according to any one of claims 2 to 4, wherein L and / or L' are identical or different at each occurrence and are of the structure of formula (L-1) or (L-2). 【Chemistry 3】 (where the dotted line is the attachment of the ancillary ligand to bridge V in formula (1) or (3) and is not present in formula (2), and where the other symbols used are: CyC, which is the same or different at each occurrence, is a substituted or unsubstituted aryl or heteroaryl group having 5 to 14 aromatic ring atoms, which in each case coordinates to the metal via a carbon atom and is bonded to CyD via a covalent bond; CyD is the same or different at each occurrence and is a substituted or unsubstituted heteroaryl group having 5-14 aromatic ring atoms, coordinated to the metal through a nitrogen atom or through a carbene carbon atom and bonded to CyC via a covalent bond; At the same time, any two or more of the substituents may together form a ring system.

6. The method according to any one of claims 2 to 5, characterized in that L and / or L' are identical or different at each occurrence and are one of the structures of formulae (L-1-1), (L-1-2) and (L-2-1) to (L-2-4). 【Chemistry 4】 where "o" in the compound of formula (1) or (3) indicates the point of attachment to the bridge V, in which case the corresponding X is C, and where the symbols used are: X is the same or different at each occurrence and is CR or N, with the proviso that at most two symbols X per ring are N; R is the same or different at each occurrence and is H, D, F, Cl, Br, I, N (R １ ) ２ , OR １ , S.R. １ , C.N., N.O. ２ , COOR １ , C(=O)N(R １ ) ２ , Si(R １ ) ３ , B(OR １ ) ２ , C(=O)R １ , P(=O)(R １ ) ２ , S(=O)R １ , S(=O) ２ R １ , OSO ２ R １ , a linear alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group is in each case one or more R １ radicals, and wherein one or more non-adjacent CH ２ The group is Si(R １ ) ２ , C=O, NR １ , O, S or CONR １ or 5 to 40 aromatic ring atoms, in each case one or more non-aromatic R １ an aromatic or heteroaromatic ring system, optionally substituted by a radical; at the same time, two R radicals may together form a ring system; R １ are the same or different for each occurrence, H, D, F, Cl, Br, I, N (R ２ ) ２ , OR ２ , S.R. ２ , C.N., N.O. ２ , Si(R ２ ) ３ , B(OR ２ ) ２ , C(=O)R ２ , P(=O)(R ２ ) ２ , S(=O)R ２ , S(=O) ２ R ２ , OSO ２ R ２ , a linear alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group is in each case one or more R ２ radicals, and wherein one or more non-adjacent CH ２ The group is Si(R ２ ) ２ , C=O, NR ２ , O, S or CONR ２ or 5 to 40 aromatic ring atoms, in each case one or more R ２ an aromatic or heteroaromatic ring system, optionally substituted by a radical; １ The radicals together may form a ring system; R ２ is the same or different at each occurrence and is H, D, F, or an aliphatic organic radical, especially a hydrocarbyl radical, having 1 to 20 carbon atoms, in which one or more hydrogen atoms may be replaced by F.

7. 7. The method according to any one of claims 2 to 6, characterized in that exactly one of the ligands or ancillary ligands L or L' is a ligand or ancillary ligand of formula (L-39) which coordinates to iridium via two D groups and which, when the complex is a complex of formula (1) or (3), is bonded to V via the position marked with "o" (in which case the corresponding X is C). 【Chemistry 5】 (where: D is C or N, with the proviso that one D is C and the other D is N; X is the same or different at each occurrence and is CR or N; Z is CR', CR or N, with the proviso that exactly one Z is CR' and the other Z is CR or N; wherein at most one symbol X or Z per ring is N; R' is a group of formula (17) or (18) 【Chemistry 6】 where the dotted lines indicate the linking of groups; R″ is the same or different at each occurrence and is H, D, F, CN, a straight chain alkyl group having 1 to 10 carbon atoms (wherein one or more hydrogen atoms may be replaced by D or F), or a branched or cyclic alkyl group having 3 to 10 carbon atoms (wherein one or more hydrogen atoms may be replaced by D or F), or an alkenyl group having 2 to 10 carbon atoms (wherein one or more hydrogen atoms may be replaced by D or F); at the same time, two adjacent R″ radicals or two R″ radicals on adjacent phenyl groups may together form a ring system; or two R″ on adjacent phenyl groups may together form C(R １ ) ２ , N.R. １ , O and S, the two phenyl groups together with the bridging group being a carbazole, dibenzofuran or dibenzothiophene, and the further group R″ is as defined above; n is 0, 1, 2, 3, 4 or 5.

8. The method of any one of claims 2 to 7, wherein the ancillary ligand L'' has the structure of formula (19) or (20): 【Chemistry 7】 wherein X has the definition as defined in claim 6, the dotted line indicates the bond to V, the * indicates coordination to the iridium atom, and further comprising: D is the same or different at each occurrence and is C or N; Q in formula (19) is a group selected from formulas (Q-1) to (Q-3), and Q in formula (20) is a group selected from formulas (Q-4) to (Q-15), 【Chemistry 8】 where the dotted line indicates in each case a bond in formula (19) or (20), * marks the position of coordination of this group to the iridium atom, and X has the definition given in claim 6.

9. 9. The method according to claim 2, wherein L' is identical to or different from L, or L' is selected from the group acetylacetonate, picolinic acid derivatives, pyrazolyl borate, or hydroxyquinolinate.

10. A process according to any one of claims 1 to 9, characterized in that V represents a group of formula (21) in which the dotted lines indicate the points of attachment of the ancillary ligands L and L'. 【Chemistry 9】 (where: X １ is the same or different at each occurrence and is CR or N; X ２ is the same or different at each occurrence and is CR or N; A is the same or different for each occurrence, CR ２ -CR ２ , C.R. ２ -O, CR ２ -NR, C(=O)-O, C(=O)-NR, or a group of formula (22): 【Chemistry 10】 where the dotted line indicates in each case the point of attachment of the bidentate ancillary ligand L or L' to this structure, and the * indicates the point of attachment to the central trivalent aryl or heteroaryl group of the unit of formula (21).

11. 11. The method according to claim 1, wherein the iridium reactant used is an iridium halide, an iridium carboxylate, a COD-iridium(I) compound, an iridium ketoketonate, or a compound of one of the formulae (34) to (39). 【Chemistry 11】 where R, CyC and CyD have the definitions set out in claims 5 and 6, and further symbols and subscripts are as follows: Hal is the same or different at each occurrence and is F, Cl, Br or I; Kat is the same or different at each occurrence and is an alkali metal cation, an ammonium cation, a tetraalkylammonium cation having 4 to 40 carbon atoms, or a tetraalkylphosphonium cation having 4 to 40 carbon atoms; z is 0 to 100; y is 0 to 100.

12. The carboxylic acid has the formula R ４ -COOH or HOOC-R ５ The structure of —COOH (wherein R ４ is a linear alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl group is in each case one or more R １ radicals), or having 2 to 20 carbon atoms and one or more R １ an alkenyl or alkynyl group having 5 to 40 aromatic ring atoms, optionally substituted by a radical, １ an aromatic or heteroaromatic ring system or a ring system having 5 to 20 aromatic ring atoms, optionally substituted by radicals, in each case one or more R １ aryl or heteroaryl groups, optionally substituted by radicals, wherein R ５ is a linear alkylene group having 1 to 20 carbon atoms or a branched or cyclic alkylene group having 3 to 20 carbon atoms, where the alkylene group is in each case composed of one or more R １ radicals), having 2 to 20 carbon atoms and one or more R １ an alkenyl or alkynyl group having 5 to 40 aromatic ring atoms, in each case one or more non-aromatic R １ a divalent aromatic or heteroaromatic ring system or a divalent ring system having 5 to 20 aromatic ring atoms, optionally substituted by radicals, in each case one or more R １ The method according to any one of claims 1 to 11, characterized in that the aryl group is selected from the group consisting of divalent aralkyl or heteroaralkyl groups, optionally substituted by radicals.

13. 13. The process according to any one of claims 1 to 12, characterized in that the carboxylic acid used is acetic acid, propionic acid, pivalic acid, benzoic acid, salicylic acid, phenylacetic acid, adipic acid, or mixtures thereof.

14. 14. The method according to claim 1, characterized in that when a hydrate is used as the iridium reactant, a water scavenger is added, in particular a carboxylic acid anhydride, a carbonyl halide, a trialkyl orthocarboxylate, a carbodiimide, phosphorus pentoxide, thionyl chloride or phosphoryl chloride.

15. 15. The method according to any one of claims 1 to 14, characterized in that when a halide is used as the iridium reactant, a halide scavenger is added, in particular an alkali metal, alkaline earth metal, ammonium or zinc salt of a carboxylate.

16. 16. The process according to any one of claims 1 to 15, characterized in that a chiral, enantiomerically pure carboxylic acid is used.

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