EMITTER MATERIAL FOR OLEDS

Description

[0001] The present invention relates to an emitter layer for an OLED, which, for example, emits circularly polarized light, wherein the emitter layer comprises a defined metal complex. The present invention further relates to an OLED comprising such an emitter layer, a method for generating light, and the use of a metal complex for generating light in an emitter layer of an OLED. Furthermore, the present invention includes a ligand for a corresponding metal complex.

[0002] OLEDs are now known for a wide variety of applications. Particularly in TVs or displays, and generally in display devices, they offer advantages due to their energy-efficient operation combined with good image quality and high contrast.

[0003] OLED-based displays are equipped with filters designed to reduce reflections from other light sources, such as daylight, thus preventing contrast loss. Linear polarizers combined with quarter-wave plates are used as filters, but this means that only about 50% of the light emitted by the emitter layer can pass through and be perceived by the user. Therefore, a high electrical power is required to compensate for this light loss and achieve the desired brightness. In contrast, the circularly polarized luminescence (CPL) generated by chiral emitter materials with a high asymmetry factor (g lumen) can pass through the filters completely, resulting in significantly higher energy efficiency. However, these technologies are not yet sufficiently well-established.

[0004] Efficient commercial OLEDs currently require phosphorescent triplet emitters, mostly in the form of metal complexes of the expensive elements iridium or platinum, to efficiently convert all excitons generated during electron-hole recombination into light. An alternative is luminescence via thermally activated delayed fluorescence (TADF), which can be achieved with complexes of the significantly cheaper element copper or inexpensive organic compounds. While green-emitting OLEDs show good performance, efficient electroluminescence in the deep red color range remains a challenge.

[0005] The use of cyclic (amino)(aryl) carbenes as chromophore ligands is described, for example, in Gernert Markus et al: "Cyclic (Amino) (aryl) carbenes Enter the Field of Chromophore Ligands: Expanded [pi] System Leads to Unusually Deep Red Emitting Cu I Compounds", JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol. 142, No. 19, April 17, 2020 (2020-04-17), pages 8897-8909, XP93033249, ISSN: 0002-7863, DOI: 10.1021 / jacs.0c02234.

[0006] The object of the present invention is therefore to overcome at least one disadvantage of the prior art, at least partially. In particular, the object of the present invention is to provide an emitter layer that enables efficient electroluminescence in the deep red color range.

[0007] This problem is at least partially solved by a compound according to claim 1. This problem is further solved at least partially by a use according to claim 8, by a metal complex according to claim 9, by a use according to claim 12, by an emitter layer for an organic light-emitting diode having the features of claim 13, by an organic light-emitting diode having the features of claim 14, and by a method having the features of claim 15. Preferred embodiments of the invention are described in the dependent claims, in the description, or in the figures, wherein further features described or shown in the dependent claims, in the description, or in the figures may, individually or in any combination, constitute an object of the invention unless the context clearly indicates otherwise.

[0008] A paracyclophane-carbene compound is described, characterized in that the paracyclophane-carbene compound corresponds to the following structure (I): where R1< is selected from aryl, heteroaryl, alkyl, perfluoroalkyl, perfluoroaryl, wherein R2< and R3< are the same or different and are independently selected from aryl, heteroaryl, alkyl, alkenyl, alkynyl, perfluoroalkyl, perfluoroaryl, wherein R4<, R5<, R6<, R7<, R8<, R9<, R10<, R11< are the same or different and are independently selected from hydrogen, deuterium, halogen, silyl, alkyl, alkenyl, alkynyl, perfluoroalkyl, aryl, heteroaryl, alkoxy, wherein R12<, R13<, R14<, R15<, R16<, R17< are the same or different and are independently selected from hydrogen, deuterium, halogen, alkyl, alkenyl, alkynyl, perfluoroalkyl, aryl, Heteroaryl, alkoxy, COR 18< , CO 2 R 19< , CONR 20< , cyano, nitro, SO 3 R 21< , PO 3 R 22< 2 , wherein R 18< R 19< , R 20< , R 21< , R 22< are the same or different and are independently selected from hydrogen, deuterium, halogen, silyl, alkyl, alkenyl, alkynyl,Perfluoroalkyl, aryl, heteroaryl, alkoxy, and where An-< is an anion.

[0009] The compound shown in structure (I) is depicted as a salt, with the cation serving as a ligand capable of forming a bond with a metal. Therefore, it is immediately clear to those skilled in the art that when the present invention refers to a corresponding ligand, it means the paracyclophane-carbene cation, which can then be, or is, bound to a metal atom, as is usual for ligands.

[0010] Basically, for example, C1 alkyl is intended to denote an alkyl group with one carbon atom, with the corresponding designations for the other groups being understood accordingly, so that, for example, C12 alkoxy denotes an alkoxy group with 12 carbon atoms.

[0011] Furthermore, the term An-< generally describes an anion regardless of its valence. The paracyclophane-carbene cation and the anion are intended to form a neutral salt. Depending on the chosen anion, one, two, or more cations may be present to form the paracyclophane-carbene compound according to structure (I), which is a neutral salt overall.

[0012] Such a paracyclophane-carbene compound according to structure (I) serves in a particularly advantageous way to form a ligand for a metal complex that serves as an emitter material in an OLED.

[0013] Regarding its use in OLEDs, thermally activated delayed fluorescence (TADF) represents an alternative to state-of-the-art solutions that can be realized with complexes of very inexpensive metals, such as copper, or with inexpensive organic compounds. While green-emitting OLEDs show good performance, efficient electroluminescence in the deep red color range remains a challenge.

[0014] The ligand according to the invention allows for the production of racemic metal complexes, such as copper(I) complexes, from commercial starting materials, in contrast to established iridium emitters. These complexes exhibit the highest radiation constants in the red range reported to date for molecular emitters, up to 2x10 6< s -1<, and have also been successfully used in a test OLED.

[0015] When used as ligands in metal complexes in emitter materials for OLEDs, the described ligands can thus enable very high luminous efficacy and significantly improve the quality of OLEDs. Furthermore, they can be operated with comparatively very low energy consumption.

[0016] Due to their chiral nature, these compounds, in their enantiomerically pure form, are also suitable in principle for use in circularly polarized luminescence (CPL) OLEDs to pass through the antireflection filters of the displays with maximum efficiency. This new class of emitters thus shows potential for commercially viable, energy-efficient applications. The positive properties can likely be further improved with continued optimization of both the molecular structure and the OLED assembly.

[0017] In principle, an emitter layer according to the present invention thus offers the possibility of being tailored for specific applications.

[0018] Furthermore, the possible synthesis routes can make the production significantly cheaper and / or simpler compared to the iridium or platein complexes used in the prior art, for example.

[0019] Thus, according to the invention, low-energy operation of an OLED can be combined with high luminous efficacy and therefore high quality at moderate costs, with a particularly high luminous efficacy in the red spectral range being possible. With regard to the paracyclophane-carbene compound, which can serve as a ligand in a metal complex of an emitter layer of an OLED, it may be particularly advantageous that R1< is selected from C5 to C18 aryl, C5 to C18 heteroaryl, C1 to C18 alkyl, C1 to C18 perfluoroalkyl, C5 to C18 perfluoroaryl, wherein R2< and R3< are the same or different and are independently selected from C5 to C18 aryl, C5 to C18 perfluoroaryl, C5 to C18 heteroaryl, C1 to C12 alkyl, C1 to C12 alkenyl, C1 to C12 alkynyl, C1 to C12 perfluoroalkyl, wherein R4<, R5<, R6<, R7<, R8<, R9<, R10<, R11< are the same or different and are independently selected from hydrogen, deuterium, halogen, silyl, C1 to C12 alkyl, C1 to C12 alkenyl, C1 to C12 alkynyl and C1 up to C12 perfluoroalkyl, C5 to C18 aryl, C5 to C18 perfluoroaryl, C5 to C18 heteroaryl, C1 to C12 alkoxy, wherein R 12< , R 13< , R 14< , R 15< , R 16< , R 17< are the same or different and are independently selected from hydrogen, C1 to C18 alkyl, C1 to C18 alkenyl, C1 to C18 alkynyl, and C1 to C18 perfluoroalkyl, C5 to C18 aryl,C5 to C18 perfluoroaryl, C5 to C18 heteroaryl, C1 to C18 alkoxy, COR 18< , CO 2 R 19< , CONR 20< , cyano, nitro, SO 3 R 21< , PO 3 R 22< 2 , wherein R 18< R 19< , R 20< , R 21< , R 22< are the same or different and are independently selected from hydrogen, deuterium, halogen, silyl, C1 to C18 alkyl, C1 to C18 alkenyl, C1 to C18 alkynyl, C1 to C18 perfluoroalkyl, C5 to C18 aryl, C5 to C18 heteroaryl, C1 to C18 alkoxy, and wherein An -< is an anion selected from halide, triflate, sulfate, phosphate, silicate, tetrafluoroborate, Hexafluorophosphate, tetraaryl borate. ,

[0020] Particularly preferably, R 1< can be selected from C9 to C18 aryl, C9 to C18 heteroaryl, C1 to C12 alkyl, C1 to C12 perfluoroalkyl, C9 to C18 perfluoroaryl, wherein R 2< and R 3< are the same or different and are independently selected from C5 to C6 aryl and C5 to C6 heteroaryl. R4<, R5<, R6<, R7<, R8<, R9<, R10<, R11< are the same or different and are independently selected from hydrogen, deuterium, halogen and silyl, C1 to C4 alkyl, C1 to C4 alkenyl, C1 to C4 alkynyl and C1 to C4 perfluoroalkyl, C5 to C6 aryl, C5 to C6 heteroaryl, C5 to C6 perfluoroaryl, C1 to C4 alkoxy, wherein R12<, R13<, R14<, R15<, R16<, R17< are the same or different and are independently selected from hydrogen, C1 to C4 alkyl, C1 to C4 alkenyl, C1 to C4 alkynyl, and C1 to C4 perfluoroalkyl, C5 to C6 aryl, C5 to C6 perfluoroaryl. C5 to C6 heteroaryl, C1 to C4 alkoxy, COR 18< , CO 2 R 19< , CONR 20< , cyano, nitro, SO 3 R 21< , PO 3 R 22< 2 , wherein R 18< R 19< , R 20< , R 21< , R 22< are the same or different and are independently selected from hydrogen, deuterium, halogen, silyl, C1 to C4 alkyl, C1 to C4 alkenyl, C1 to C4 alkynyl, C1 to C4 perfluoroalkyl, C5 to C12 aryl,C5 to C12 heteroaryl, C1 to C4 alkoxy, and where An -< is an anion selected from halide, triflate, sulfate, phosphate, silicate, tetrafluoroborate, hexafluorophosphate, tetraarylborate.

[0021] R< 1 is particularly preferably a dialkylphenyl. For example, the dialkylphenyl can be 2,6-di-isopropylphenyl.

[0022] It may still be preferred that R2< and R3< are phenyl. In principle, the phenyl rings can be substituted, but it is also possible for the phenyl rings to be unsubstituted.

[0023] It is further preferably provided that R 4< , R 5< , R 6< , R 7< , R 8< , R 9< , R 10< and R 11< are hydrogen.

[0024] Additionally or alternatively, it may be advantageous that R 12< R 13< , R 14< , R 15< , R 16< and R 17< are hydrogen.

[0025] In a specific embodiment of the present invention, it may be provided that the paracyclophane-carbene compound has the following structure (II):

[0026] In this structure, the residue "dipp" is said to represent 2,6-di-isopropylphenyl and the anion OTF-< is said to be a triflate group, which can also be called a trifluoromethanesulfonate group.

[0027] According to the foregoing, an object of the present invention is further a use of a paracyclophane-carbene compound, as described above, for the production of a metal complex for an emitter material of an emitter layer of an organic light-emitting diode.

[0028] In summary, as described in detail above with regard to the paracyclophane-carbene compound, this allows for the combination of low-energy operation of an OLED with high luminous efficacy and thus high quality at moderate costs, whereby in particular high luminous efficacy in the red spectral range is possible.

[0029] Regarding further advantages and technical features of the paracyclophane-carbene compound as well as its use, reference is made to the description of the metal complex, its use as an emitter material in an emitter layer, the emitter layer, the organic light-emitting diode, the process, the figures as well as the description of the figures.

[0030] Furthermore, a metal complex is described. The metal complex is characterized by the fact that it corresponds to the following structure (III): L 1< Me[L 2< ] m [L 3< ] m (III), where L1< is a paracyclophane-carbene ligand as described above, where L2< and L3< are the same or different and are independently selected from NR23< 2 , NR24< 3 , PR25< 2 , PR26< 3 , OR27< 2 , OR28< , SR29< , SR30< 2 , SR31< , SeR32< 2 , SeR34< , TeR35< 2 , TeR36< , silyl, aryl, heteroaryl, alkenyl, alkynyl, isonitrile, cyclopentadienyl, halogen, where m is a number selected from 0, 1 or 2 with the proviso that at least one m is non-zero, where R23< , R24< , R25< , R26< , R 27< , R 28< , R 29< , R 30< , R 31< , R 32< , R 33< , R 34< , R 35< , R 36< are the same or different and are independently selected from aryl, heteroaryl, alkenyl, alkynyl, alkyl, perfluoroalkyl, perfluoroaryl; and wherein Me is a metal selected from copper, silver and gold.

[0031] Regarding the description of ligand L1< as a paracyclophane-carbene ligand, the following should be noted. As is comprehensively described and generally known for carbenes, the paracyclophane-carbene-based salt reacts with a base, and the resulting neutral carbene ligand binds to the metal. In other words, the paracyclophane-carbene compound can also be described as the corresponding ligand salt with the paracyclophane-carbene structural unit as the ligand.

[0032] In principle, in addition to ligand L1, the metal in the metal complex can have either only one ligand L2 but no ligand L3, only one ligand L3 but no ligand L2, or both ligands L2 and L3. Furthermore, ligands L2 and L3 can be separated, or there can be one ligand L2 that binds to the metal with two bonds and can therefore be described as a bridging ligand or chelating ligand.

[0033] Such a metal complex serves in particular as an emitter material in the emitter layer of an organic light-emitting diode (OLED). This offers the particular advantage of enabling efficient electroluminescence, especially in the deep red color range. This is often still a challenge with prior art solutions.

[0034] The metal complex according to the invention allows for the production of racemic metal complexes from commercial starting materials, in contrast to established iridium emitters, which, due to TADF, exhibit the highest radiation constants in the red range reported to date for molecular emitters, up to 2x10 6< s -1<, and have also been successfully applied in a test OLED.

[0035] In summary, a very high luminous efficacy can be achieved, thus significantly increasing the quality of OLEDs. Furthermore, they can be operated with comparatively very low energy consumption.

[0036] Thus, according to the invention, low-energy operation of an OLED can be combined with high luminous efficacy and therefore high quality at moderate costs, with a particularly high luminous efficacy in the red spectral range being possible.

[0037] It may be preferable that L 1< is a paracyclophane-carbene ligand as described above, wherein Me is a metal selected from copper, silver and gold, and wherein L 2< is a ligand selected from a heteroaryl and a halogen.

[0038] For example, it may be preferable to L 1< is a paracyclophane-carbene ligand as described above, wherein Me is copper, and wherein L 2< is a ligand selected from a carbazole ligand and a halogen.

[0039] In particular, using a copper complex, cost-effective complexes can be formed compared to prior art iridium complexes. Accordingly, the advantages in this respect can be particularly pronounced.

[0040] In a specific embodiment, the metal complex may be selected from structures (IV), (V), (VI), (VII), (VIII) and (IX) as shown below:

[0041] Following the foregoing, a further object of the present invention is the use of a metal complex as described above as an emitter material in an emitter layer of an organic light-emitting diode.

[0042] In summary, as described above in detail with regard to the paracyclophane-carbene compound and the corresponding metal complex, this allows for the combination of low-energy operation of an OLED with high luminous efficacy and thus high quality at moderate costs, whereby in particular high luminous efficacy in the red spectral range is possible.

[0043] Regarding further advantages and technical features of the metal complex and its use as an emitter material in an emitter layer, reference is made to the description of the paracyclophane-carbene compound as well as its use, the emitter layer, the organic light-emitting diode, the process, the figures as well as the description of the figures.

[0044] Furthermore, an emitter layer for an organic light-emitting diode is described, comprising a metal complex for emitting light, characterized in that the metal complex is formed as described above.

[0045] This document describes an emitter layer for an organic light-emitting diode (OLED). In principle, the OLED can be constructed using methods known from the prior art. Therefore, no special requirements need to be met to implement the emitter layer described above in an OLED.

[0046] The emitter layer is characterized by the fact that it contains a metal complex as the active emitter material, as described above. In a general form, the emitter layer contains a metal complex corresponding to the following structure (III): L1< Me[L2< ] m [L3< ] m (III), where L1< is a paracyclophane-carbene ligand as described above, where L2< and L3< are the same or different and are independently selected from NR23< 2 , NR24< 3 , PR25< 2 , PR26< 3 , OR27< 2 , OR28< , SR29< , SR30< 2 , SR31< , SeR32< 2 , SeR34< , TeR35< 2 , TeR36< , silyl, aryl, heteroaryl, alkenyl, alkynyl, isonitrile, cyclopentadienyl, halogen, where m is a number selected from 0, 1 or 2 with the proviso that at least one m is non-zero, where R23< , R24< , R25< , R26< , R 27< , R 28< , R 29< , R 30< , R 31< , R 32< , R 33< , R 34< , R 35< , R 36< are the same or different and are independently selected from aryl, heteroaryl, alkenyl, alkynyl, alkyl, perfluoroalkyl, perfluoroaryl; and wherein Me is a metal selected from copper, silver and gold.

[0047] In principle, it may be preferred that L 1< is a paracyclophane-carbene ligand as described above, wherein Me is a metal selected from copper, silver and gold, and wherein L 2< is a ligand selected from a heteroaryl and a halogen.

[0048] For example, it may be preferable to L 1< is a paracyclophane-carbene ligand as described above, wherein Me is copper, and wherein L 2< is a ligand selected from a carbazole ligand and a halogen.

[0049] In particular, using a copper complex, cost-effective complexes can be formed compared to prior art iridium complexes. Accordingly, the advantages in this respect can be particularly pronounced.

[0050] In a specific embodiment, the metal complex may be selected from structures (IV), (V), (VI), (VII), (VIII) and (IX) as shown below:

[0051] In summary, the ligand according to the invention allows for the production of racemic metal complexes, such as copper(I) complexes, from commercially available starting materials, in contrast to established iridium emitters. These complexes exhibit the highest radiation constants in the red range reported to date for molecular emitters, up to 2x10 6< s -1<, and have also been successfully used in a test OLED.

[0052] When used as ligands in metal complexes in emitter materials for OLEDs, the described ligands can thus enable very high luminous efficacy and significantly improve the quality of OLEDs. Furthermore, they can be operated with comparatively very low energy consumption.

[0053] Thus, according to the invention, low-energy operation of an OLED can be combined with high luminous efficacy and therefore high quality at moderate costs, with a particularly high luminous efficacy in the red spectral range being possible.

[0054] Regarding further advantages and technical features of the emitter layer, reference is made to the description of the paracyclophane-carbene compound as well as its use, the metal complex, its use as an emitter material in an emitter layer, the organic light-emitting diode, the process, the figures as well as the description of the figures.

[0055] Furthermore, an organic light-emitting diode (OLED) is described, comprising a cathode, an emitter layer, a hole conduction layer and an anode, characterized in that the emitter layer is designed as described above.

[0056] Accordingly, the metal complex forming the emitter material and located in the emitter layer can correspond to the following structure (III): L 1< Me[L 2< ] m [L 3< ] m (III), where L1< is a paracyclophane-carbene ligand as described above, where L2< and L3< are the same or different and are independently selected from NR23< 2 , NR24< 3 , PR25< 2 , PR26< 3 , OR27< 2 , OR28< , SR29< , SR30< 2 , SR31< , SeR32< 2 , SeR34< , TeR35< 2 , TeR36< , silyl, aryl, heteroaryl, alkenyl, alkynyl, isonitrile, cyclopentadienyl, halogen, where m is a number selected from 0, 1 or 2 with the proviso that at least one m is non-zero, where R23< , R24< , R25< , R26< , R 27< , R 28< , R 29< , R 30< , R 31< , R 32< , R 33< , R 34< , R 35< , R 36< are the same or different and are independently selected from aryl, heteroaryl, alkenyl, alkynyl, alkyl, perfluoroalkyl, perfluoroaryl; and wherein Me is a metal selected from copper, silver and gold.

[0057] The metal complex of the emitter layer may be further developed, as described above in detail with reference to the description of the metal complex.

[0058] As described above in greater detail with regard to the emitter layer, the use of the copper complex as the emitter material in the emitter layer offers the advantages of low-energy operation of a suitably equipped OLED in combination with high luminous efficacy, especially in the red spectral range, while also enabling cost-effective manufacturing.

[0059] The structure of the OLED, comprising the layers cathode, emitter layer, hole conduction layer and anode, can in principle be designed as is known from the prior art.

[0060] For example, the cathode can be made of or consist of a metal or metal alloy, so that the cathode or its material has a low work function. Examples include calcium, aluminum, barium, ruthenium, or a magnesium-silver alloy.

[0061] The anode can be, for example, a metallic oxide, such as indium tin oxide (ITO).

[0062] The hole transport layer (HTL) can be a molecular or polymeric material, such as poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS).

[0063] The emitter layer comprises, in particular, the copper complex described above as the emitter material. This is preferably present in a dilute form, with concentrations of, for example, 1–10 wt%, preferably 1–5 wt%, in a suitable matrix, the proportions described above referring to the entire emitter layer. A suitable matrix material can, for example, be 1,3-bis(N-carbazolyl)benzene (mCP).

[0064] Regarding the matrix material, a wide range of options is generally available, as long as the energy levels allow for energy transfer or direct recombination on the emitter. The precise material must be selected based on the chosen Cu complex energies, i.e., the specific ligands selected.

[0065] Furthermore, the layer structure described above can be applied to a substrate, such as a glass substrate.

[0066] The manufacturing and construction of OLEDs can, in principle, correspond to those of the state of the art.

[0067] In principle, the OLED can consist only of the layers described above; however, further layers are not excluded but are intended to be encompassed by the present invention. For example, optimized, doped charge transport layers or charge / exciton blocking layers are conceivable. The additional layers can, for example, serve to tailor the energy of the successive functional layers, such as balancing the charge carrier injection asymmetry, generating targeted energy cascades to optimize energy transfer to the emitter, etc.

[0068] It may be preferred that the organic light-emitting diode further incorporates a filter to reduce reflections from external light sources, wherein the filter is at least partially opaque to linearly polarized light.

[0069] In addition to the layers described above, the layer structure or the OLED preferably includes a filter or filter combination designed to reduce reflections from external light sources. This filter combination consists, in particular, of a linear polarizer and a quarter-wave plate. Such a filter combination is characterized by the fact that it filters out at least some linearly polarized light from the beam path, thereby filtering out, for example, daylight. While in standard OLEDs, some of the generated linearly polarized light is blocked by this filter arrangement and does not contribute to light generation, with the proposed emitters, which emit, in particular, circularly polarized light, every generated light particle can, in principle, be extracted and contribute to light generation.This results in a significant reduction in daylight reflections, while the internally generated light passes completely through the filter arrangement, thus significantly improving the contrast of an image emitted by an OLED, especially under traditionally difficult usage situations such as strong sunlight outdoors.

[0070] Such a filter can offer particular advantages in the case of an OLED as described above, since an OLED equipped with a linear polarizer as a filter does not reduce the luminous efficacy of circularly polarized light. Therefore, a high-quality image can be achieved, especially in the case of an OLED according to the invention.

[0071] Regarding further advantages and technical features of the organic light-emitting diode, reference is made to the description of the paracyclophane-carbene compound as well as its use, the metal complex, its use as emitter material in an emitter layer, the emitter layer, the process, the figures as well as the description of the figures.

[0072] Furthermore, a method for generating particularly circularly polarized light using an organic light-emitting diode is described, comprising the following process steps: a) Providing an organic light-emitting diode as described above; and b) Applying a voltage between the anode and the cathode to inject charge carriers and to generate, in particular, circularly polarized light.

[0073] With reference to process step a) and in particular with regard to the training and further development of the OLED or especially the emitter material in the emitter layer, full reference is made to the corresponding description of the OLED or the emitter layer.

[0074] By applying a voltage between the anode and cathode, which is feasible within the parameters known to those skilled in the art of OLEDs, the emitter material in the emitter layer can be excited to emit, in particular, circularly polarized light. This is surprisingly possible with the high-luminous-efficiency copper complex described above, which offers significant advantages.

[0075] The OLED can be operated in a voltage range of a few volts and a current density range of up to 1 A / cm², which is typical for established OLED architectures, for example at 10 mA / cm². This allows the OLED, with its particularly circularly emitting active layer, to be controlled by established electrical circuits and implemented in existing designs (e.g., display units).

[0076] In summary, it can be permitted that images with high light yield, especially in the red spectral range, and good contrast can be generated using the metal complexes described above as emitter material, while also enabling energy-efficient operation.

[0077] Regarding further advantages and technical features of the process, reference is made to the description of the paracyclophane-carbene compound as well as its use, the metal complex, its use as an emitter material in an emitter layer, the emitter layer, the organic light-emitting diode, the figures as well as the description of the figures.

[0078] The invention is explained below by way of example with reference to the accompanying drawings and examples, wherein the features shown below can each individually or in combination represent an aspect of the invention, and wherein the invention is not limited to the following drawing, the following description and the following embodiment.

[0079] They show: Fig. 1 a schematic representation of the structure of an OLED in an embodiment according to the present invention; Fig. 2a schematic representation of the structure of an OLED in a further embodiment according to the present invention; Fig. 3 a reaction scheme for the preparation of the paracyclophane-carbene compound according to the invention; Fig. 4 a < 1 H-NMR spectrum of compound 6; Fig. 5 a 13< C-NMR spectrum of compound 6; Fig. 6 a < 1 H-NMR spectrum of compound 7; Fig. 7 a 13< C-NMR spectrum of compound 7; Fig. 8 a < 1H NMR spectrum of compound 9; Fig. 9 a 13< C-NMR spectrum of compound 9; Fig. 10 a 1 H-NMR spectrum of compound 10; Fig. 11 a 13 C-NMR spectrum of compound 10; Fig. 12 a 1 H-NMR spectrum of compound 11; Fig. 13 a 13< C-NMR spectrum of compound 11; Fig. 14 a 1 H-NMR spectrum of compound 12; Fig. 15 a 13 C-NMR spectrum of compound 12; Fig. 16normalized excitation and emission spectra of compounds 6, 7 and 8; Fig. 17 normalized excitation and emission spectra of compounds 9, 10, 11 and 12; Fig. 18 normalized excitation and emission spectra of compounds 9, 10, 11 and 12; Fig. 19 an EL spectrum of an exemplary OLED; and Fig. 20 The current-voltage characteristic curve at positive voltage of an example OLED.

[0080] In the Figure 1 Figure 10 shows an embodiment of a layer structure for an OLED according to an embodiment of the present invention. The layer structure 10 comprises an anode 14, a cathode 16, and an emitter layer 18. The anode 14 can be made of a material with a moderate work function, such as ITO, and the cathode 16 can be made of a material with a low work function, such as calcium. The emitter layer 18 comprises a metal complex as described below.

[0081] Furthermore, layer 20 is shown, which represents a hole-conducting layer. This can be realized, for example, by the hole-conducting polymer poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS).

[0082] In principle, further layers can be present without departing from the scope of the invention. For example, a hole transport layer can be provided between emitter layer 18 and hole conduction layer 20, and / or an electron transport layer can be present between emitter layer 18 and cathode 16. In principle, the transport layers can also function as exciton and charge carrier blocking layers, or, due to their energetic properties, fulfill several functions in one.

[0083] In the Figure 2Furthermore, a cover layer 22, such as a cover glass, is shown, which delimits the layer structure 10 from above. A sealant 24 is shown between the cover layer 22 and the substrate 12, which may consist of an adhesive, such as an epoxy adhesive. The substrate 12, the cover layer 22, and the sealant thus encapsulate the layer structure 10 and protect it from external influences. This minimizes, for example, the degradation of calcium and organic matter. A protective gas, such as nitrogen, may be present within the encapsulation.

[0084] What the various designs have in common is... Figures 1 and 2 that the emitter layer 18 has a defined copper complex as the emitter material. It is provided that the metal complex corresponds to the following structure (III): L 1< Mre[L 2< ][L 3< ] m (III), wherein L 1< is a paracyclophane-carbene ligand according to any one of claims 1 to 8, wherein L 2< and L 3< are the same or different and are independently selected from NR 23< 2 , NR 24< 3 , PR 25< 2 , PR 26< 3 , OR 27< 2 , OR 28< , SR 29< , SR 30< 2 , SR 31< , SeR 32< 2 , SeR 34< , TeR 35< 2 , TeR 36< , silyl, aryl, heteroaryl, alkenyl, alkynyl, isonitrile, cyclopentadienyl, halogen, wherein m is a number selected from 0, 1 or 2 with the proviso that at least one m is non-zero, wherein R 23< , R 24< , R 25< , R 26< , R 27< , R 28< , R 29< , R 30< , R 31< , R 32< , R 33< , R 34< , R 35< , R 36< are the same or different and are independently selected from aryl, heteroaryl, alkenyl, alkynyl, alkyl, perfluoroalkyl, perfluoroaryl; and wherein Me is a metal selected from copper, silver and gold.

[0085] For example, the metal complex may be selected from structures (IV), (V), (VI), (VII), (VIII) and (IX) as shown below:

[0086] The following section presents synthesis examples for the emitter materials defined above, which are present in emitter layer 18. First, the synthesis of the ligands is discussed, in particular that of ligand L1<. Subsequently, the synthesis of various metal complexes is described.

[0087] As shown below, structure (II) corresponds to compound 6, structure (IV) to compound 7, structure (VI) to compound 9, structure (VII) to compound 10, structure (VIII) to compound 11, structure (IX) to compound 12, structure (IV) to compound 7, structure (IV) to compound 7. Synthesis examples for the ligand contained in the copper complex

[0088] The synthesis of the paracyclophane-carbene ligand or the paracyclophane-carbene compound can proceed according to Scheme 1, which is described as Figure 3 shown.

[0089] In detail, the synthesis proceeds as follows: rac-4-Formyl[2.2]paracyclophan (compound 1)

[0090]

[0091] In a 500 mL Schlenk flask, 2.00 g (9.60 mmol, 1.0 eq.)-[2.2]paracyclophane were cooled to 0°C in 150 mL DCM. 0.90 mL (10 mmol, 1.05 eq.) titanium(IV) chloride and 2.1 mL (19 mmol, 2 eq.) dichloromethoxymethane were carefully added and the mixture stirred overnight. The black reaction solution was placed on 200 mL of ice. The turquoise suspension was stirred for 2 h. The colorless organic phase was separated, and the colorless aqueous phase was extracted twice with 50 mL DCM. The combined organic phase was dried with Na₂SO₄, filtered, and all volatile components were removed under reduced pressure. The product was obtained as a colorless solid (2.10 g, 8.89 mmol, 93%) after washing with pentane.

[0092] The spectroscopic data are known from the literature. rac-4-Formyl[2.2]paracyclophan-O-methylaldoximes (compound 3)

[0093]

[0094] In a 100 mL Schlenk flask, 424 mg (5.08 mmol, 1.2 eq.) of methoxyamine hydrochloride, 0.67 mL (8.4 mmol, 2 eq.) of pyridine, and 0.5 g of molecular sieve (4 Å) were stirred in 12 mL of DCM for 5 min. 1.00 g (4.23 mmol, 1 eq.) of rac-4-formyl[2,2]paracyclophane was added, and the mixture was stirred overnight. The yellow reaction mixture was extracted three times with 20 mL of DCM and filtered over silica, with all volatile components removed under reduced pressure. The product was obtained by column chromatography (silica; pentane:ethyl acetate 100:0 → 50:1) as a colorless solid (660 mg, 2.49 mmol, 59%).

[0095] The spectroscopic data are known from the literature. rac-4-Bromo-5-formy[2.2]paracyclophan-O-methylaldoximes (compound xx)

[0096]

[0097] 200 mg (754 µmol, 1 eq.) were added to a 100 ml Young tube. rac-4-Formyl[2,2]paracyclophan-O-methylaldoxime, 34 mg (0.15 mmol, 0.2 eq.) palladium(II) acetate, 33 mg (0.15 mmol, 0.2 eq.) silver(I) trifluoroacetate, and 161 mg (905 pmol, 1.2 eq.) N-bromsuccinimide were stirred in 25 mL of DCE for 6 h at 100°C. The reaction mixture was cooled to room temperature and treated with 25 mL of DCM and 20 mL of distilled water. The aqueous phase was extracted twice with 20 mL of DCM. The organic phase was dried with magnesium sulfate, filtered through Celite, and all volatile components were removed under reduced pressure. The crude product was used without further work-up.

[0098] The spectroscopic data are known from the literature. rac-4-Bromo-5-forrnyl[2.2]paracyclophan (compound 4)

[0099]

[0100] In a 10 ml microwave vial, 160 mg (465 µmol, 1 eq.) rac-4-Bromo-5-formyl[2.2]paracyclophan-O-methylaldoximes, 180 mg (946 µmol, 2.0 eq.) para-Toluenesulfonic acid monohydrate and 0.35 ml (4.7 mmol, 10 eq., 37% in water) formaldehyde in 5 ml THF and 1 ml water were irradiated with microwaves at 70 W (120°C) for 4 h. The reaction mixture was cooled to room temperature and all volatile components were removed under reduced pressure. The product was obtained by column chromatography (silica; cyclohexane:ethyl acetate 100:0 → 50:1) as a colorless solid (140 mg, 0.444 mmol, 96%).

[0101] The spectroscopic data are known from the literature. rac-4-Bromo-5-formyl[2.2]paracyclophan-N-(2,6-diisopropylphenyl)methanimine (Compound 5)

[0102]

[0103] To a solution of 100 mg (317 pmol, 1.0 eq.) rac-4-bromo-5-formyl[2,2]paracyclophan and 0.60 mg (0.34 mmol, 1.1 eq.) N-(2,6-diisopropylphenylamine) in 1 ml toluene, 0.07 ml (0.6 mmol, 2 eq.) titanium(IV) chloride was carefully added at 0°C and heated to reflux for 2 h. The orange reaction mixture was added to 3 ml isopropanol. 3 ml distilled water and 4 ml diethyl ether were added. The aqueous phase was extracted twice with 5 ml diethyl ether. The combined organic phase was dried with Na₂SO₄, decanted, and all volatile components were removed under reduced pressure. The product was identified by column chromatography (silica; cyclohexane:ethyl acetate 100:0 → 50:1) as a yellow Oil 100 mg, 0.211 mmol, 66%) obtained.

[0104] The <1H NMR data are as follows: (500 MHz, CDCl 3 ) δ8.26 (s, 1H), 7.21 (m, 2H), 7.15 m, 1H), 6.98 (m, 1H), 6.67 (m, 2H), 6.58 (m, 3H), 4.26 (m, 1H), 3.56 (m, 1H), 3.19 (m, 5H), 3.10 (m, 1H), 2.93 (m, 2H), 1.28 (d, J = 6.8 Hz, 6H), 1.24 (d, J = 6.9 Hz, 6H). (HiPC)(OTf) (Connection 6)

[0105]

[0106] At -80°C, a solution of 5.40 g (11.4 mmol, 1.0 eq.) rac-4-Bromo-5-formyl[2.2]paracyclophan-N-(2,6-diisopropylphenyl)methanimine in 15 ml diethyl ether was slowly dissolved in 4.8 ml (2.5 M, 12 mmol, 1.05 eq.) n< Butyllithium was added. The red solution was stirred for 1 h at -80°C. A solution of 2.20 g (12.1 mmol, 1.05 eq.) of benzophenone in 10 mL of Et₂O was added at -80°C, causing the solution to change color from green to violet. Stirring continued for 30 min at -80°C and 30 min at room temperature. To the yellow-orange solution, 2.0 mL (12 mmol, 1.05 eq.) of trifluoromethanesulfonic anhydride was added at -80°C and warmed to room temperature overnight. The precipitated yellow solid was filtered off and washed three times with 5 mL of diethyl ether. The product was obtained as yellow crystals (3.60 g, 5.07 mmol, 45%) by sublimation of diethyl ether into a THF solution.

[0107] The spectroscopic data are as follows and in the Figures 4 ( 1< H-NMR) and 5 ( 13< C-NMR) shown: 1< H-NMR (600 MHz, CD 2 Cl 2 ) δ9.65 (s, 1H), 8.10 (bs, 1H), 7.71 (bs, 1H), 7.56 (m, 1H), 7.45 (bs, 1H), 7.37 (m, 1H), 7.33 (m, 1H), 7.30 (m, 1H), 7.17 (bs, 1H), 7.05 (bs, 1H), 6.93 (m, 1H), 6.85 (m, 1H), 6.82 (m, 1H), 6.80 (m, 1H), 6.78 (m, 1H), 6.61 (m, 1H), 5.29 (m, 1H), 3.99 (m, 1H), 3.75 (m, 1H), 3.56 (m, 1H), 3.31 (sept, J = 6.7 Hz, 1H), 3.17 (m, 1H), 2.97 (m, 1H), 2.78 (m, 1H), 2.60 (m, 1H), 2.40 (m, 1H), 1.31 (d, J = 6.7 Hz, 3H), 0.86 (sept., J = 6.7 Hz, 1H), 0.70 (d, J = 6.8 Hz, 3H), 0.49 (d, J = 6.7 Hz, 3H), -0.12 (d, J = 6.6 Hz, 3H).

[0108] 13< C-NMR (151 MHz, CD 2 Cl 2 ) δ 174.0 (s), 148.6 (s), 147.2 (s), 146.8 (s), 146.7 (s), 143.3 (s), 140.6 (s), 138.9 (s), 137.9 (s), 137.1 (s), 133.6 (s), 133.0 (s), 132.7 (s), 132.0 (s), 131.9 (s), 131.6 (s), 131.2 (s), 130.8 (s), 130.54 (d, J= 1.5 Hz), 130.2 (s), 130.1 (s), 128.8 (s), 126.6 (s), 124.8 (s), 95.7 (s), 35.1 (s), 34.5 (s), 32.8 (s), 31.1 (s), 29.8 (s), 26.2 (s), 25.4 (s), 22.9 (s), 21.7 (s).

[0109] 15<N-NMR (60.8 MHz, CD 2 Cl 2 ) δ -163.4.

[0110] 19< F-NMR (565 MHz, THF) δ -78.55.

[0111] Elemental analysis: Calculated: C, 72.76; H, 5.96; N, 1.97; Measured: C, 72.8; H, 6.2; N, 1.9. Synthesis examples of various copper complexes that can serve as emitter material [CuCl(iPC)] (Compound 7)

[0112]

[0113] At -85°C, a solution of 69 mg (0.43 mmol, 1 eq.) of KHMDS in 2 ml of THF was slowly added to a suspension of 300 mg (423 pmol, 1.0 eq.) of [iPCH](OTf) and 70 mg of copper(I) chloride · dimethyl sulfide (0.44 mmol, 1.05 eq.) in 20 ml of THF. The yellow-orange suspension was warmed to room temperature overnight. All volatile components of the yellow-green suspension were removed under reduced pressure. After extraction with DCM and filtration over basic aluminum oxide, the crude product was precipitated by the addition of pentane and washed twice with 2 ml of pentane. The product was obtained as orange crystals (112 mg, 170 pmol, 40%) by sublimation of pentane into a THF / cyclohexane solution as a 1:1 adduct with THF.

[0114] The spectroscopic data are as follows and in the Figure 6 ( 1< H-NMR) and 7 ( 13< C-NMR) shown: 1< H-NMR (600 MHz, THF) δ7.82 (m, 1H), 7.67 (m, 1H), 7.43 (m, 1H), 7.34 (m, 1H), 7.24 (m, 3H), 7.11 (bs, 2H), 6.95 (m, 1H), 6.90 (m, 1H), 6.79 (m, 1H), 6.74 (m, 1H), 6.67 (m, 1H), 6.58 (m, 1H), 6.38 (m, 1H), 5.00 (m, 1H), 4.81 (m, 1H), 3.54 (sept., J = 6.7 Hz, 1H), 3.48 (m, 1H), 3.23 (m, 1H), 2.94 (m, 1H), 2.71 (m, 1H), 2.54 (m, 1H), 2.41 (m, 1H), 1.35 (d, J = 6.8 Hz, 3H), 1.10 (sept., J = 6.8 Hz, 1H), 0.81 (d, J = 6.7 Hz, 3H), 0.49 (d, J = 6.7 Hz, 3H), -0.20 (d, J = 6.7 Hz, 3H).

[0115] 13< C-NMR (151 MHz, THF) δ 229.4 (s), 149.6 (s), 145.9 (s), 144.8 (s), 143.1 (s), 143.1 (s), 140.4 (s), 139.6 (s), 139.3 (s), 138.9 (s), 136.4 (s), 136.1 (s), 134.7 (s), 133.5 (s), 132.9 (s), 132.8 (s), 132.7 (s), 132.6 (s), 131.6 (s), 131.0 (s), 130.3 (s), 129.5 (s), 129.2 (s), 129.1 (s), 128.3 (s), 125.9 (s), 124.4 (s), 95.8 (s), 35.6 (s), 34.8 (s), 34.4 (s), 30.6 (s), 30.3 (s), 29.9 (s), 27.1 (s), 23.2 (s), 21.3 (s). Elementary analysis: Calculated: C, 75.17; H, 6.97; N, 1.83; Measured: C, 75.1; H, 6.9; N, 1.9. [CuBr(iPC)] (Connection 8)

[0116]

[0117] At -85°C, a solution of 69 mg (0.43 mmol, 1 eq.) of KHMDS in 2 ml of THF was slowly added to a suspension of 300 mg (423 pmol, 1.0 eq.) of [iPCH](OTf) and 87 mg of copper(I) bromide · dimethyl sulfide (0.42 mmol, 1.05 eq.) in 20 ml of THF. The yellow-orange suspension was warmed to room temperature overnight. All volatile components of the yellow-orange suspension were removed under reduced pressure. After extraction with DCM and filtration over basic aluminum oxide, the crude product was precipitated by the addition of pentane and washed twice with 2 ml of pentane. The product was obtained as orange crystals (21 mg, 30 µmol, 7%) by sublimation of pentane into a THF / cyclohexane solution.

[0118] The spectroscopic data are as follows: 1< H-NMR (600 MHz, THF) δ7.82 (m, 1H), 7.67 (m, 1H), 7.43 (m, 1H), 7.34 (m, 1H), 7.24 (m, 3H), 7.11 (bs, 2H), 6.95 (m, 1H), 6.90 (m, 1H), 6.79 (m, 1H), 6.74 (m, 1H), 6.67 (m, 1H), 6.58 (m, 1H), 6.38 (m, 1H), 5.00 (m, 1H), 4.81 (m, 1H), 3.54 (sept., J = 6.7 Hz, 1H), 3.48 (m, 1H), 3.23 (m, 1H), 2.94 (m, 1H), 2.71 (m, 1H), 2.54 (m, 1H), 2.41 (m, 1H), 1.35 (d, J = 6.8 Hz, 3H), 1.10 (sept., J = 6.8 Hz, 1H), 0.81 (d, J = 6.7 Hz, 3H), 0.49 (d, J = 6.7 Hz, 3H), -0.20 (d, J = 6.7 Hz, 3H). Elementar Analyse: Berechnet: C, 71.73; H, 5.88; N, 1.99; Gemessen: C, 71.4; H, 6.0; N, 1.8. [Cu(Cbz)(iPC)] (Connection 9)

[0119]

[0120] In a 20 mL screw-top vial, 16 mg (78 pmol, 1.03 eq.) of KCbz were added to a solution of 50 mg (76 pmol, 1.0 eq.) of [CuCl(iPC)] in 4 mL of THF and stirred overnight. The deep red suspension was treated with 2 mL of diethyl ether and filtered through basic aluminum oxide under reduced pressure to one-quarter of its original volume. The product was obtained by sublimation of a mixture of cyclohexane and pentane into the solution as a 2:3 adduct with THF, forming yellow crystals (45 mg, 57 pmol, 75%).

[0121] The spectroscopic data are as follows and in the Figure 8 ( 1< H-NMR) and 9 ( 13< C-NMR) shown: 1< H-NMR (600 MHz, THF) δ 7.96 m, 1H), 7.83 m, 2H), 7.67 (m, 1H), 7.49 (m, 1H), 7.45 (m, 1H), 7.38 (m, 2H), 7.29 (m, 1H), 7.17 (bs, 21H), 7.01 (m, 1H), 6.97 (m, 4H), 6.80 (m, 3H), 6.73 (m, 3H), 6.62 (m, 1H), 6.50 (m, 1H), 5.13 (m, 2H), 3.90 (m, 1H), 3.72 (m, 1H), 3.64 (Sept., J= 6.8 Hz, 1H), 3.37 (m, 1H), 2.98 (m, 1H), 2.74 (m, 1H), 2.61 (m, 1H), 2.43 (m, 1H), 1.26 (m, 1H), 1.13 (d, J = 6.7 Hz, 3H), 0.87 (d, J = 6.8 Hz, 3H), 0.51 (d, J = 6.7 Hz, 3H), - 0.16 (d, J = 6.7 Hz, 3H).

[0122] 13< C-NMR (151 MHz, THF) δ 230.9 (s), 151.0 (s), 150.3 (s), 146.4 (s), 144.7 (s), 143.3 (s), 143.3 (s), 140.2 (s), 139.9 (s), 139.4 (s), 136.4 (s), 136.3 (s), 134.9 (s), 133.6 (s), 133.1 (s), 132.9 (s), 132.8 (s), 132.6 (s), 131.6 (s), 131.1 (s), 130.5 (s), 129.6 (s), 129.3 (s), 129.2 (s), 128.2 (s), 126.5 (s), 125.4 (s), 125.1 (s), 123.5 (s), 119.4 (s), 115.6 (s), 115.0 (s), 96.0 (s), 35.7 (s), 35.1 (s), 30.8 (s), 30.4 (s), 30.1 (s), 26.8 (s), 26.2 (s), 25.5 (s), 23.2 (s), 21.7 (s). Elementaranalyse: Berechnet: C, 80.28; H, 6.85; N, 3.12; Gemessen: C, 79.9; H, 6.9; N, 3.3. [Cu(Cbz tBu< )(ipC)l (Connection 10)

[0123]

[0124] In a 20 mL screw-top vial, 28 mg (77 µmol, 1 eq.) of [KCbz tBu< · (Et₂O) 2 / 3 ] were added to a solution of 50 mg (76 pmol, 1.0 eq.) of [CuCl(iPC)] in 4 mL of THF and stirred overnight. The deep red suspension was treated with 2 mL of diethyl ether and filtered through basic aluminum oxide under reduced pressure to one-quarter of its original volume. The product was obtained by sublimation of a mixture of cyclohexane and pentane into the solution as a 4:5 adduct with THF, forming yellow crystals (51 mg, 57 pmol, 75%).

[0125] The spectroscopic data are as follows and in the Figures 10 ( 1< H-NMR) and 11 ( 13< C-NMR) shown: 1< H-NMR (600 MHz, THF) δ7.94 (m, 1H), 7.91 (m, 2H), 7.66 (m, 1H), 7.50 (m, 1H), 7.44 (m, 1H), 7.39 (m, 1H), 7.36 (m, 1H), 7.28 (m, 1H), 7.16 (bs, 2H), 7.08 (m, 2H), 6.99 (m, 1H), 6.97 (m, 1H), 6.91 (m, 1H), 6.76 (m, 1H), 6.68 (m, 2H), 6.61 (m, 1H), 6.53 (m, 1H), 5.12 (m, 1H), 5.09 (m, 1H), 3.82 (m, 1H), 3.67 (m, 1H), 3.29 (m, 1H), 2.94 (m, 1H), 2.70 (m, 1H), 2.58 (m, 1H), 2.41 (m, 1H), 1.41 (s, 18H), 1.26 (m, 1H), 1.12 (d, J = 6.7 Hz, 3H), 0.84 (d, J = 6.7 Hz, 3H), 0.50 (d, J = 6.7 Hz, 3H), -0.17 (d, J = 6.7 Hz, 3H).

[0126] 13< C-NMR (151 MHz, THF) δ231.0 (s), 150.3 (s), 149.6 (s), 146.3 (s), 144.7 (s), 143.3 (s), 143.2 (s), 140.2 (s), 139.8 (s), 139.8 (s), 139.4 (s), 137.6 (s), 136.4 (s), 136.2 (s), 135.0 (s), 133.7 (s), 133.0 (s), 132.9 (s), 132.8 (s), 132.6 (s), 131.5 (s), 131.0 (s), 130.4 (s), 129.5 (s), 129.3 (s), 129.1 (s), 128.2(s), 126.4 (s), 125.3 (s), 125.0 (s), 121.1 (s), 115.3 (s), 114.5 (s), 95.9 (s), 35.6 (s), 35.0 (s), 34.9 (s), 32.6 (s), 30.8 (s), 30.4 (s), 30.1 (s), 26.9 (s), 23.2 (s), 21.7 (s).

[0127] Elemental analysis: Calculated: 81.13; H, 7.62; N, 2.82; Measured: C, 81.0; H, 7.3; N, 3.1. [Cu( Me< Cbz)(iPC)] (Connection 11)

[0128]

[0129] In a 20 mL screw-top vial, 17 mg (78 µmol, 1 eq.) of KMeCbz were added to a solution of 50 mg (76 pmol, 1.0 eq.) of [CuCl(iPC)] in 4 mL of THF and stirred overnight. The deep red suspension was treated with 2 mL of diethyl ether and filtered through basic aluminum oxide under reduced pressure to one-quarter of its original volume. The product was obtained by sublimation of a mixture of cyclohexane and pentane into the solution as a 2:3 adduct with THF, forming yellow crystals (48 mg, 60 pmol, 79%).

[0130] The spectroscopic data are as follows and in the Figure 12 (1< H-NMR) and 13 ( 13< C-NMR) shown: 1< H-NMR (600 MHz, THF) δ 7.95 (m, 1H), 7.87 (m, 1H), 7.78 (m, 1H), 7.74 (m, 1H), 7.60 (bs, 1H), 7.48 (m, 1H), 7.39 (m, 1H), 7.29 (m, 3H), 7.22 (m, 2H), 7.02 (m, 3H), 6.93 (m, 1H), 6.90 (m, 1H), 6.86 (m, 1H), 6.82 (m, 1H), 6.79 (m, 1H), 6.78 (m, 1H), 6.69 (m, 1H), 6.61 (m, 1H), 6.40 (m, 1H), 5.06 (m, 1H), 4.97 (m, 1H), 3.64 (sept.,J = 6.7 Hz, 1H), 3.60 (m, 1H), 3.53 (m, 1H), 3.18 (m, 1H), 2.99 (m, 1H), 2.74 (m, 1H), 2.65 (m, 1H), 2.61 (s, 3H), 2.42 (m, 1H), 1.25 (m, 1H), 1.09 (d, J = 6.8 Hz, 3H), 0.94 (d, J = 6.7 Hz, 3H), 0.47 (d, J = 6.7 Hz, 3H). 13< C-NMR (151 MHz, THF) δ 231.4 (s), 151.2 (s), 149.8 (s), 149.6 (s), 145.9 (s), 144.8 (s), 143.5 (s), 143.0 (s), 140.3 (s), 140.0 (s), 139.7 (s), 139.5 (s), 136.5 (s), 136.4 (s), 135.1 (s), 133.7 (s), 133.0 (s), 132.7 (s), 132.7 (s), 132.5 (s), 131.8 (s), 131.0 (s), 130.6 (s), 129.6 (s), 129.4 (s), 129.3 (s), 128.2 (s), 126.3 (s), 125.9 (s), 125.3 (s), 124.8 (s), 124.6 (s), 123.2 (s), 121.5 (s), 119.5 (s), 117.6 (s), 115.8 (s), 115.8 (s), 115.7 (s), 96.1 (s), 35.7 (s), 34.6 (s), 30.8 (s), 30.5 (s), 30.2 (s), 27.0 (s), 26.2 (s), 23.5 (s), 21.7 (s), 20.9 (s).

[0131] Elementaranalyse: Berechnet: C, 80.36; H, 6.97; N, 3.07; Gemessen: C, 80.4; H, 6.9; N, 3.3. [Cu( OMe< Cbz)(iPC)] (Connection 12)

[0132]

[0133] In a 20 mL screw-top vial, 20 mg (76 µmol, 1 eq.) of [K₂OMe<CBz · (Et₂O)₁ / 3] were added to a solution of 50 mg (76 pmol, 1.0 eq.) of [CuCl(iPC)] in 4 mL of THF and stirred overnight. The deep red suspension was treated with 2 mL of diethyl ether and filtered through basic aluminum oxide under reduced pressure to one-quarter of its original volume. The product was obtained by sublimation of a mixture of cyclohexane and pentane into the solution as a 2:3 adduct with THF, forming yellow crystals (46 mg, 56 pmol, 74%).

[0134] The spectroscopic data are as follows and in the Figure 14 ( 1< H-NMR) and 15 ( 13< C-NMR) shown: 1< H-NMR (600 MHz, THF) δ 8.01 (m, 1H), 7.81 (m, 1H), 7.73 (m, 1H), 7.55 (m, 1H), 7.47 (m, 1H), 7.38 (m, 1H), 7.28 (m, 1H), 7.26 (m, 1H), 7.24 (d, J= 2.8 Hz, 1H), 7.23 (m, 1H), 7.01 (m, 1H), 6.89 (m, 2H), 6.84 (m, 1H), 6.80 (m, 3H), 6.75 (m, 2H), 6.68 (m, 1H), 6.59 (m, 1H), 6.40 (m, 1H), 5.03 (m, 1H), 4.94 (m, 1H), 4.05 (s, 3H), 3.71 (sept., J = 6.7 Hz, 1H), 3.55 (m, 1H), 3.45 (m, 1H), 3.14 (m, 1H), 2.98 (m, 1H), 2.73 (m, 1H), 2.63 (m, 1H), 2.45 (m, 1H), 1.30 (sept., J = 6.7 Hz, 1H), 1.28 (d, J = 6.8 Hz, 3H), 0.98 (d, J = 6.7 Hz, 3H), 0.52 (d, J = 6.7 Hz, 3H), -0.13 (d, J = 6.7 Hz, 3H).

[0135] 13< C-NMR (151 MHz, THF) δ232.0 (s), 150.5 (s), 149.8 (s), 148.2 (s), 146.0 (s), 145.4 (s), 143.8 (s), 143.2 (s), 141.1 (s), 140.4 (s), 139.6 (s), 139.5 (s), 139.4 (s), 136.4 (s), 135.9 (s), 135.2 (s), 133.7 (s), 132.9 (s), 132.7 (s), 132.6 (s), 131.7 (s), 130.9 (s), 130.3 (s), 129.5 (s), 129.2 (s), 128.1 (s), 126.6 (s), 126.0 (s), 125.5 (s), 124.6 (s), 123.1 (s), 119.4 (s), 116.2 (s), 115.5 (s), 115.4 (s), 113.1 (s), 103.7 (s), 96.0 (s), 55.5 (s), 35.8 (s), 34.9 (s), 34.8 (s), 30.8 (s), 30.5 (s), 30.1 (s), 26.9 (s), 23.4 (s), 21.7 (s).

[0136] Elemental analysis: Calculated: C, 79.47; H, 6.67; N, 3.14; Measured: C, 79.4; H, 6.3; N, 3.4. The following describes the photophysical properties of compounds according to the invention. UV-Vis spectra were recorded on a PerkinElmer LAMBDA™ < 265 instrument. Lifetime determinations and recordings of excitation and emission spectra were performed using an Edinburgh Instruments FLSP920 spectrometer. The emission radiation was recorded at a 90° angle to the excitation radiation. Quantum yields were determined using an integrating sphere. All measurements were performed in 1 cm³ quartz glass cuvettes.

[0137] Figure 16Figure 1 shows normalized excitation and emission spectra of compounds 6, 7, and 8, with the corresponding curves labeled with the numbers of the respective compounds. Normalized excitation and emission spectra are shown in the ground solid (line) or in a PMMA matrix (dashes). The band in the emission spectra at 425 nm represents scattering of the light used to excite the sample.

[0138] Selected photophysical data of compounds 6, 7 and 8 under argon at room temperature are further shown in Table 1.

[0139] Figure 17 Figure 1 shows normalized excitation (left) and emission spectra (right) of compounds 9, 10, 11 and 12 in THF solution (below) or PMMA matrix (above), with the corresponding curves labelled with the numbers of the respective compound.

[0140] Figure 18Figure 1 shows normalized excitation (left) and emission spectra (right) of compounds 9, 10, 11 and 12 in ground (bottom) or microcrystalline (top) state, with the corresponding curves labelled with the numbers of the respective compound.

[0141] Selected photophysical data for compounds 9, 10, 11 and 12 under argon at room temperature or under helium at 77 K and under vacuum at 6 K are further shown in Table 2.

[0142] λ The maximum value (PL) indicates the maximum photoluminescence and is therefore an important parameter for the resulting color perceived by the eye. The wavelengths found here are in the near-infrared range, up to 785 nm, making them interesting for various luminescence applications.

[0143] The quantum yield ΦPL is a measure of the efficiency of a luminophore. It indicates what proportion of excited states radiate into the ground state and can be understood as the ratio of emitted to absorbed photons. Although the ΦPL given here refers to PL, this value is also an interesting measure of the efficiency of electroluminescence within an electrically driven component. The lifetime τ is a measure of how quickly the luminophores return to their ground state after excitation (emitting a photon when Φ PL = 1). τ It should be as small as possible to avoid "efficiency roll-off" effects in OLEDs. The radiating rate constant k can be determined from Φ PL and τ. R = Φ PL / τ. This allows the complexes to be compared with other emitters. The highest value determined here of kR = 19 x 10⁵ s⁻¹ already exceeds many currently used Ir or Pt emitters. Generally, there are hardly any emitter materials that exhibit such a high radiative rate constant.

[0144] The chiroptical properties of compounds according to the invention are described below.

[0145] The anisotropy factors gabs and glum are a measure of how much left- or right-handed photons dominate over the others during absorption or emission. The following applies: g lum = 2 Δ I I = I L − I R 1 2 I L + I R where IL and IR represent the intensity of left-handed (L) and right-handed (R) photons, respectively. The equation yields maxima of +2 for pure left-handed and -2 for pure right-handed emitted light. For octahedral transition metal complexes (such as Ir(III)) and comparable known copper complexes, these values ​​rarely exceed 10⁻³.

[0146] Similarly g abs = Δϵ ϵ = ϵ L − ϵ R 1 2 ϵ L + ϵ R from the extinction coefficients ε L and ε Rfor the respective absorbed photons. g abs is actually less important for us. An anisotropy factor was used for the lowest energy absorption. g abs ≈ 2x10 -3< calculated. The g abs The lowest energy band should be of the same order of magnitude as the g lum Value, since the same electronic states should be involved in the emission of a TADF mechanism as in the lowest-energy absorption (cf. Einstein coefficients). According to the invention, a value of g lum Approximately 2x10 -3< is expected. This is then quite comparable to those of phosphorescent or TADF emitters.

[0147] Regarding the application in organic light-emitting diodes, the following should be noted.

[0148] By integrating a molecular emitter into an organic light-emitting diode (OLED), electrical excitation of the molecule is possible, analogous to optical excitation (PL), a process known as electroluminescence (EL). OLEDs are particularly relevant for display / screen applications. The described TADF emission characteristics of the emitters according to the invention, combined with high quantum efficiencies ΦPL, make these materials especially interesting for use in OLED devices, as theoretically high external quantum efficiencies (EQE) can be achieved. The EQE is defined by the number of photons coupled out of the OLED per injected charge carrier. A key influencing factor is the internal quantum efficiency (IQE), which can reach a maximum of 100% for phosphorescent and TADF emitters.

[0149] To test the electroluminescent operation of the iPC emitters, compound 10 was integrated into a simple proof-of-concept OLED. The component architecture can be used in conjunction with Figure 1 The following can be described: Indium tin oxide (ITO) acts as the transparent anode 14 (hole-injecting contact), PEDOT:PSS as the hole injection / transport material, and calcium / aluminum as the electron-injecting top contact. The emitter is embedded in a matrix material (mCP) via solution processing at a rate of 10 wt%, based on the layer. This emitting layer (consisting of the emitter and matrix) is located between the PEDOT:PSS layer and the top contact. Upon bipolar charge carrier injection into the emitting layer, excitons (excited states) are generated on the emitter, which can decay radiatively (EL) and result in light extraction via the transparent ITO anode.

[0150] Figure 19Furthermore, it shows that the measured EL spectra agree with the PL spectra with respect to their spectral position and shape, demonstrating that the emitter according to compound 10 can be electrically driven in OLED devices. The current density is within the typical range for OLEDs. As expected, the EL intensity scales with increasing current density. Curve A shows a current density of 33 mA / cm² and curve B shows a current density of 17 mA / cm².

[0151] Figure 20 The graph shows the current-voltage characteristic at positive voltage (forward bias) and exhibits typical diode behavior. It becomes clear that the current flow in the OLED is dominated by the injection across the contact interfaces.

Claims

1. A paracyclophane-carbene compound, characterized in that the paracyclophane-carbene compound corresponds to the following structure (I): wherein R1 is selected from aryl, heteroaryl, alkyl, perfluoroalkyl, perfluoroaryl, wherein R2 and R3 are the same or different and are independently selected from aryl, heteroaryl, alkyl, alkenyl, alkynyl, perfluoroalkyl, perfluoroaryl, wherein R4, R5, R6, R7, R8, R9, R10, R11 are the same or different and are independently selected from hydrogen, deuterium, halogen, silyl, alkyl, alkenyl, alkynyl, perfluoroalkyl, aryl, heteroaryl, alkoxy, wherein R12, R13, R14, R15, R16, R17 are the same or different and are independently selected from hydrogen, deuterium, halogen, alkyl, alkenyl, alkynyl, perfluoroalkyl, aryl, heteroaryl, alkoxy, COR18, CO2R19, CONR20, cyano, nitro, SO3R21, PO3R222, wherein R18, R19, R20, R21, R22 are the same or different and are independently selected from hydrogen, deuterium, halogen, silyl, alkyl, alkenyl, alkynyl, perfluoroalkyl, aryl, heteroaryl, alkoxy, and wherein An- is an anion.

2. Paracyclophane-carbene compound according to claim 1, characterised in that R1 is selected from C5 to C18 aryl, C5 to C18 heteroaryl, C1 to C18 alkyl, C1 to C18 perfluoroalkyl, C5 to C18 perfluoroaryl, wherein R2 and R3 are the same or different and are independently selected from C5 to C18 aryl, C5 to C18 perfluoroaryl, C5 to C18 heteroaryl, C1 to C12 alkyl, C1 to C12 alkenyl, C1 to C12 alkynyl, C1 to C12 perfluoroalkyl, wherein R4, R5, R6, R7, R8, R9, R10, R11 are the same or different and are independently selected from hydrogen, deuterium, halogen, silyl, C1 to C12 alkyl, C1 to C12 alkenyl, C1 to C12 alkynyl and C1 to C12 perfluoroalkyl, C5 to C18 aryl, C5 to C18 perfluoroaryl, C5 to C18 heteroaryl, C1 to C12 alkoxy, wherein R12 R13, R14, R15, R16, R17 are the same or different and are independently selected from hydrogen, C1 to C18 alkyl, C1 to C18 alkenyl, C1 to C18 alkynyl, and C1 to C18 perfluoroalkyl, C5 to C18 aryl, C5 to C18 perfluoroaryl, C5 to C18 heteroaryl, C1 to C18 alkoxy, COR18, CO2R19, CONR20, cyano, nitro, SO3R21, PO3R222, wherein R18 R19, R20, R21, R22 are the same or different and are independently selected from hydrogen, deuterium, halogen, silyl, C1 to C18 alkyl, C1 to C18 alkenyl, C1 to C18 alkynyl, C1 to C18 perfluoroalkyl, C5 to C18 aryl, C5 to C18 heteroaryl, C1 to C18 alkoxy, and wherein An- is an anion selected from halide, triflate, sulphate, phosphate, silicate, tetrafluoroborate, hexafluorophosphate, tetraarylborate.

3. Paracyclophane-carbene compound according to claim 1 or 2, characterized in that R1 is selected from C9 to C18 aryl, C9 to C18 heteroaryl, C1 to C12 alkyl, C1 to C12 perfluoroalkyl, C9 to C18 perfluoroaryl, wherein R2 und R3 are the same or different and are independently selected from C5 to C6 aryl and C5 to C6 heteroaryl, R4, R5, R6, R7, R8, R9, R10, R11 are the same or different and are independently selected from hydrogen, deuterium, halogen and silyl, C1 to C4 alkyl, C1 to C4 alkenyl, C1 to C4 alkinyl and C1 to C4 perfluoroalkyl, C5 to C6 aryl, C5 to C6 heteroaryl, C5 to C6 perfluoroaryl, C1 to C4 alkoxy, wherein R12 R13, R14, R15, R16, R17 are the same or different and are independently selected from hydrogen, C1 to C4 alkyl, C1 to C4 alkenyl, C1 to C4 alkynyl, and C1 to C4 perfluoroalkyl, C5 to C6 aryl, C5 to C6 perfluoroaryl, C5 to C6 heteroaryl, C1 to C4 alkoxy, COR18, CO2R19, CONR20, cyano, nitro, SO3R21, PO3R222, wherein R18 R19, R20, R21, R22 are the same or different and are independently selected from hydrogen, deuterium, halogen, silyl, C1 to C4 alkyl, C1 to C4 alkenyl, C1 to C4 alkynyl, C1 to C4 perfluoroalkyl, C5 to C12 aryl, C5 to C12 heteroaryl, C to C4 alkoxy, and wherein An- is an anion selected from halide, triflate, sulphate, phosphate, silicate, tetrafluoroborate, hexafluorophosphate, tetraarylborate.

4. Paracyclophane-carbene compound according to any one of claims 1 to 3, characterized in that R1 is dialkylphenyl.

5. Paracyclophane-carbene compound according to any one of claims 1 to 4, characterized in that R2 and R3 are phenyl.

6. Paracyclophane-carbene compound according to any one of claims 1 to 5, characterized in that R4, R5, R 6 , R7, R8, R9, R10 and R11 and / or that R12 R13, R14, R15, R16 and R17 are hydrogen.

7. Paracyclophane-carbene compound according to any one of claims 1 to 6, characterized in that the paracyclophane-carbene compound has the following structure (II):

8. Use of a paracyclophane-carbene compound according to any one of claims 1- 7 for preparing a metal complex for an emitter material of an emitter layer of an organic light-emitting diode.

9. Metal complex, characterized in that the metal complex corresponds to the following structure (III):         L1Me[L2]m[L3]m     (III), wherein L1 is a paracyclophane-carbene ligand according to any one of claim 1 to 8, wherein L2 and L3 are the same or different and are independently selected from NR232, NR243, PR252, PR263, OR272, OR28, SR29, SR302, SR31, SeR322, SeR34, TeR352, TeR36, silyl, aryl, heteroaryl, alkenyl, alkynyl, isonitrile, cyclopentadienyl, halogen, wherein m is a number selected from 0, 1 or 2, with the proviso that at least one m is not equal to zero, wherein R23, R24, R25, R26, R27, R28, R29, R30, R31, R32, R33, R34, R35, R36 are the same or different and are independently selected from aryl, heteroaryl, alkenyl, alkynyl, alkyl, perfluoroalkyl, perfluoroaryl; and wherein Me is a metal selected from copper, silver and gold.

10. Metal complex according to claim 9, characterized in that L1 is a paracyclophane-carbene ligand according to any one of claims 1 to 7, wherein Me is a metal selected from copper, silver and gold, and wherein L2 is a ligand selected from a heteroaryl and a halogen or that Me is copper, wherein L2 is a ligand selected from a carbazole-ligand and a halogen.

11. Metal complex according to any one of claim 9 to 10, characterized in that the metal complex is selected from the structures (IV), (V), (VI), (VII), (VIII) and (IX) as shown below:

12. Use of a metal complex as emitter material in an emitter layer of an organic light-emitting diode, characterized in that the metal complex is formed according to any one of claims 9 to 11.

13. Emitter layer for an organic light-emitting diode, having a metal complex for emitting light, characterized in that the metal complex is formed according to any one of claims 9 to 11.

14. Organic light-emitting diode comprising a cathode, an emitter layer, a hole transport layer and an anode, characterized in that the emitter layer is formed according to claim 13 and, optionally, the presence of a filter for the reduction of reflexions from external light sources, wherein the filter is at least partially not permeable for polarized light.

15. A method for generating light by means of an organic light-emitting diode, comprising the steps of: a) providing an organic light-emitting diode according to claim 14, and b) applying a voltage between the anode and the cathode to inject charge carriers and generate light.