Metal complexes

Abstract

The present invention relates to iridium complexes suitable for use in organic electroluminescent devices, especially as emitters.

Claims

1. Compound of the formula (1) ##STR00403## where the symbols used are as follows: L.sup.1 is a sub-ligand of the formula (2) which coordinates to the iridium via the two nitrogen atoms identified by * and which is bonded to V via the dotted bond, ##STR00404## where: A is the same or different at each instance and is CR or N, where not more than one A group per ring is N; R.sup.B is the same or different at each instance and is F, OR.sup.1, a straight-chain alkyl group having 1 to 10 carbon atoms or a branched or cyclic alkyl group having 3 to 10 carbon atoms, where the alkyl group in each case may be substituted by one or more R.sup.1 radicals, or an aromatic ring system which has 5 to 24 aromatic ring atoms and may be substituted in each case by one or more R.sup.1 radicals; at the same time, the two R.sup.B radicals together may also form a ring system; L.sup.2 is a bidentate, monoanionic sub-ligand which coordinates to the iridium via one carbon atom and one nitrogen atom or via two carbon atoms; L.sup.3 is a bidentate, monoanionic sub-ligand which coordinates to the iridium via one carbon atom and one nitrogen atom or via two carbon atoms, or is a sub-ligand of the formula (2) which may be the same as or different from L.sup.1; V is a group of the formula (3), where the dotted bonds each represent the bonds to the sub-ligands L.sup.1, L.sup.2 and L.sup.3, ##STR00405## X.sup.1 is the same or different at each instance and is CR or N; X.sup.2 is the same or different at each instance and is CR or N, or two adjacent X.sup.2 groups together are NR, O or S, thus forming a five-membered ring; or two adjacent X.sup.2 groups together are CR or N when one of the X.sup.3 groups in the cycle is N, thus forming a five-membered ring; with the proviso that not more than two adjacent X.sup.2 groups in each ring are N; X.sup.3 is C at each instance in one cycle or one X.sup.3 group is N and the other X.sup.3 group in the same cycle is C, where the X.sup.3 groups in the three cycles may be selected independently, with the proviso that two adjacent X.sup.2 groups together are CR or N when one of the X.sup.3 groups in the cycle is N; R is the same or different at each instance and is H, D, F, Cl, Br, I, N(R.sup.1).sub.2, OR.sup.1, SR.sup.1, CN, NO.sub.2, COOH, C(═O)N(R.sup.1).sub.2, Si(R.sup.1).sub.3, B(OR.sup.1).sub.2, C(═O)R.sup.1, P(═O)(R.sup.1).sub.2, S(═O)R.sup.1, S(═O).sub.2R.sup.1, OSO.sub.2R.sup.1, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R.sup.1 radicals and where one or more nonadjacent CH.sub.2 groups may be replaced by Si(R.sup.1).sub.2, C═O, NR.sup.1, O, S or CONR.sup.1, or an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more R.sup.1 radicals; at the same time, two R radicals together may also form a ring system; R.sup.1 is the same or different at each instance and is H, D, F, Cl, Br, I, N(R.sup.2).sub.2, OR.sup.2, SR.sup.2, CN, NO.sub.2, Si(R.sup.2).sub.3, B(OR.sup.2).sub.2, C(═O)R.sup.2, P(═O)(R.sup.2).sub.2, S(═O)R.sup.2, S(═O).sub.2R.sup.2, OSO.sub.2R.sup.2, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R.sup.2 radicals and where one or more nonadjacent CH.sub.2 groups may be replaced by Si(R.sup.2).sub.2, C═O, NR.sup.2, O, S or CONR.sup.2, or an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more R.sup.2 radicals; at the same time, two or more R.sup.1 radicals together may form a ring system; R.sup.2 is the same or different at each instance and is H, D, F or an aliphatic, aromatic and/or heteroaromatic organic radical having 1 to 20 carbon atoms, in which one or more hydrogen atoms may also be replaced by F; at the same time, the three bidentate ligands L.sup.1, L.sup.2 and L.sup.3, apart from by the V group, may also be closed by a further bridge to form a cryptate.

2. Compound according to claim 1, wherein the group of the formula (3) is selected from the structures of the formulae (4b) to (7b) ##STR00406## where the symbols have definitions as given in claim 1.

3. Compound according to claim 1, wherein the group of the formula (3) is selected from the structures of the formulae (4c) and (5c): ##STR00407## where the symbols have definitions as given in claim 1.

4. Compound according to claim 1, wherein the sub-ligand L.sup.1 has a structure of the formula (2a) ##STR00408## where the symbols have definitions as given in claim 1 and the substituents R adjacent to the coordinating nitrogen atom are the same or different at each instance and are selected from the group consisting of H, D, F, methyl, ethyl and phenyl.

5. Compound according to claim 1, wherein the sub-ligand L.sup.1 has a structure of the formula (2c) ##STR00409## where the symbols have definitions as given in claim 1.

6. Compound according to claim 1, wherein the substituents R.sup.B are the same or different at each instance and are selected from the group consisting of OR.sup.3 where R.sup.3 is an alkyl group having 1 to 5 carbon atoms, a straight-chain alkyl group having 1 to 5 carbon atoms, a branched or cyclic alkyl group having 3 to 6 carbon atoms, and an aryl group which has 6 to 10 carbon atoms and may be substituted by one or more R.sup.1 radicals, where the two R.sup.B radicals together may also form a ring system; or in that the two R.sup.B radicals together with the boron atom to which they are bonded represent a group of one of the following formulae (B-1) to (B-8): ##STR00410## where R.sup.1 and R.sup.2 have definitions given in claim 1, the dotted bonds to the boron atom each represent the bond to the pyrazolyl ring or, when A=N, the triazolyl ring, and the negative charge on the boron atom is not shown.

7. Compound according to claim 1, wherein L.sup.3 represents a sub-ligand of the formula (2), where the sub-ligands L.sup.1 and L.sup.3 may be the same or different.

8. Compound according to claim 1, wherein L.sup.2 has one carbon atom and one nitrogen atom as coordinating atoms.

9. Compound according to claim 1, wherein the sub-ligand L.sup.2 is a structure of one of the formulae (L-1) or (L-2), and in that the sub-ligand L.sup.3, when it coordinates to the iridium via one carbon atom and one nitrogen atom or two carbon atoms, is a structure of one of the formulae (L-1) and (L-2) ##STR00411## where the dotted bond represents the bond of the sub-ligand to the group of the formula (3) and the other symbols used are as follows: CyC is the same or different at each instance and is a substituted or unsubstituted aryl or heteroaryl group which has 5 to 14 aromatic ring atoms and coordinates in each case to the metal via a carbon atom and which is bonded to CyD via a covalent bond; CyD is the same or different at each instance and is a substituted or unsubstituted heteroaryl group which has 5 to 14 aromatic ring atoms and coordinates to the metal via a nitrogen atom or via a carbene carbon atom and which is bonded to CyC via a covalent bond; at the same time, two or more substituents together may form a ring system.

10. Compound according to claim 9, wherein CyC represents an aryl or heteroaryl group which has 6 to 13 aromatic ring atoms and coordinates to the metal via a carbon atom and which may be substituted by one or more R radicals and which is bonded to CyD via a covalent bond, and in that CyD represents a heteroaryl group which has 5 to 13 aromatic ring atoms and coordinates to the metal via an uncharged nitrogen atom or via a carbene carbon atom and which may be substituted by one or more R radicals and which is bonded to CyC via a covalent bond.

11. Compound according to claim 1, wherein the sub-ligand L.sup.2 is substituted by a substituent of the formula (52) or (53) ##STR00412## where the dotted bond indicates the linkage of the group to the sub-ligand L.sup.2 and, in addition: R′ is the same or different at each instance and is selected from the group consisting of H, D, F, CN, a straight-chain alkyl group having 1 to 10 carbon atoms in which one or more hydrogen atoms may also be replaced by D or F, or a branched or cyclic alkyl group having 3 to 10 carbon atoms in which one or more hydrogen atoms may also be replaced by D or F, or an alkenyl group having 2 to 10 carbon atoms in which one or more hydrogen atoms may also be replaced by D or F; at the same time, two adjacent R′ radicals or two R′ radicals on adjacent phenyl groups together may also form a ring system; or two R′ on adjacent phenyl groups together are a group selected from O and S, such that the two phenyl rings together with the bridging group are a dibenzofuran or dibenzothiophene, and the further R′ are as defined above; n is 0, 1, 2, 3, 4 or 5.

12. Process for preparing a compound according to claim 1, wherein an iridium salt is reacted with a ligand precursor in the presence of a pyrazolylborate synthon and in the presence of a halogen scavenger.

13. Formulation comprising at least one compound according to claim 1 and at least one solvent and/or at least one further organic or inorganic compound.

14. A method of preparing an electronic device including an anode, a cathode and at least one layer, said method comprising incorporating a compound according to claim 1 in the at least one layer of the electronic device.

15. Electronic device comprising at least one compound according to claim 1.

16. Electronic device according to claim 15, wherein the electronic device is an organic electroluminescent device and the compound according to claim 1 is present together with a matrix material in one or more emitting layers.

17. Compound according to claim 6, wherein the substituents R.sup.B are the same or different at each instance and include in at least one instance an aryl group which has 6 to 10 carbon atoms and substituted by one or more R.sup.1 radicals, wherein R.sup.1 is selected from H, D, F, Cl, Br, I, N(R.sup.2).sub.2, OR.sup.2, SR.sup.2, CN, NO.sub.2, Si(R.sup.2).sub.3, B(OR.sup.2).sub.2, C(═O)R.sup.2, P(═O)(R.sup.2).sub.2, S(═O)R.sup.2, S(═O).sub.2R.sup.2, OSO.sub.2R.sup.2, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R.sup.2 radicals and where one or more nonadjacent CH.sub.2 groups may be replaced by Si(R.sup.2).sub.2, C═O, NR.sup.2, O, S or CONR.sup.2.

Description

EXAMPLES

(1) The syntheses which follow, unless stated otherwise, are conducted under a protective gas atmosphere in dried solvents. The metal complexes are additionally handled with exclusion of light or under yellow light. The solvents and reagents can be purchased, for example, from Sigma-ALDRICH or ABCR. The respective figures in square brackets or the numbers quoted for individual compounds relate to the CAS numbers of the compounds known from the literature. In the case of compounds that can have multiple tautomeric forms, one tautomeric form is shown in a representative manner.

A: Synthesis of the Synthons S

Example S1

(2) ##STR00304##

(3) To a well-stirred mixture of 11.2 g (100 mmol) of 1H-pyrazole-4-boronic acid [763120-58-7], 28.3 g (100 mmol) of 2-bromoiodobenzene [583-55-1] and 21.2 g (200 mmol) of sodium carbonate in 300 ml of dioxane and 50 ml of water are added 1.63 g (2 mmol) of dichloro[1,1′-bis(diphenylphosphino)ferrocene]palladium(II)×CH.sub.2Cl.sub.2, and the mixture is then heated under reflux for 16 h. After cooling, 300 ml of saturated sodium chloride solution are added, and the organic phase is removed and dried over magnesium sulfate. The desiccant is filtered out of the mixture using a silica gel bed in a dioxane slurry, the filtrate is concentrated under reduced pressure and the residue is subjected to flash chromatography (Torrent automatic column system from A. Semrau). Yield: 12.0 g (54 mmol), 54%. Purity: about 95% by .sup.1H NMR.

(4) In an analogous manner, it is possible to prepare the following compounds:

(5) TABLE-US-00001 Ex. Reactants Product Yield S2 05 06 57% S3 07 08 51% S4 09 0 45% S5 50% S6 48% S7 52% S8 53% S9 0 45%

Example S30

(6) ##STR00321##

(7) A well-stirred mixture of 66.3 g (100 mmol) of 2,2′-[5″-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-[1,1′:2′,1″:3″,1′″:2′″,1″″-quinquephenyl]-4,4″″-diyl]bispyridine [1989597-72-9], 22.3 g (100 mmol) of S1, 21.2 g (200 mmol) of sodium carbonate, 1.23 g (3 mmol) of SPhos, 449 mg (2 mmol) of palladium(II) acetate, 300 ml of toluene, 100 ml of ethanol and 300 ml of water is heated under reflux for 16 h. After cooling, the mixture is extended with 300 ml of toluene, and the organic phase is removed, washed once with 500 ml of water and once with 500 ml of saturated sodium chloride solution and dried over magnesium sulfate. After the desiccant has been filtered off using a Celite bed in a toluene slurry and the solvent has been removed under reduced pressure, the residue is recrystallized from acetonitrile/ethyl acetate. Yield: 49.6 g (73 mmol), 73%. Purity: about 97% by .sup.1H NMR.

(8) In an analogous manner, it is possible to prepare the following compounds:

(9) TABLE-US-00002 Ex. Reactants Product Yield S31 70% S32 75% S33 72% S34 70% S35 0 67% S36 76% S37 78% S38 64% S39 77% S40 0 73% S41 69% S42 76%

Example S50

(10) ##STR00346##

(11) To a well-stirred mixture of 18.2 g (50 mmol) of 2,2′-(5-chloro-1,3-phenylene)bis[4,4,5,5-tetramethyl-1,3,2-dioxaborolane [1417036-49-7], 22.3 g (100 mmol) of S1 and 21.2 g (200 mmol) of sodium carbonate in 300 ml of toluene, 200 ml of ethanol and 300 ml of water are added 1.6 g (6 mmol) of triphenylphosphine and then 449 mg (2 mmol) of palladium(II) acetate, and the mixture is then heated under reflux for 24 h. After cooling, the toluene phase is removed and washed once with 300 ml of water and once with 300 ml of saturated sodium chloride solution, and then dried over magnesium sulfate. The mixture is filtered through a Celite bed in a toluene slurry, the toluene is removed under reduced pressure and the residue is recrystallized from acetonitrile/methanol. Yield: 12.7 g (32 mmol), 64%. Purity: about 95% by .sup.1H NMR.

Example S51

(12) ##STR00347##

(13) To a mixture of 19.8 g (50 mmol) of S50, 14.0 g (55 mmol) of bis(pinacolato)diborane [78183-34-3], 8.2 g (100 mmol) of sodium acetate and 50 g of glass beads (diameter 3 mm) in 300 ml of THE are successively added 534 mg (1.3 mmol) of SPhos and then 224 mg (1 mmol) of palladium(II) acetate, and the mixture is stirred under reflux for 16 h. After cooling, the reaction mixture is filtered through a Celite bed in a THE slurry. The filtrate is concentrated to dryness under reduced pressure, and the residue is extracted by stirring in 200 ml of warm methanol. The product is filtered off with suction, washed twice with 50 ml each time of methanol and dried under reduced pressure. Yield: 23.0 g (47 mmol), 94%. Purity: about 95% by .sup.1H NMR.

Example S60

(14) ##STR00348##

(15) A well-stirred mixture of 48.8 g (100 mmol) of S51, 31.0 g (100 mmol) of 2-(2′-bromo[1,1′-biphenyl]-4-yl)pyridine [1374202-35-3], 21.2 g (200 mmol) of sodium carbonate, 1.23 g (3 mmol) of SPhos, 449 mg (2 mmol) of palladium(II) acetate, 300 ml of toluene, 100 ml of ethanol and 300 ml of water is heated under reflux for 16 h. After cooling, the mixture is extended with 300 ml of toluene, and the organic phase is removed, washed once with 500 ml of water and once with 500 ml of saturated sodium chloride solution and dried over magnesium sulfate. After the desiccant has been filtered off using a Celite bed in a toluene slurry and the solvent has been removed under reduced pressure, the residue is recrystallized from acetonitrile/ethyl acetate. Yield: 37.3 g (63 mmol), 63%. Purity: about 97% by .sup.1H NMR.

(16) In an analogous manner, it is possible to prepare the following compounds:

(17) TABLE-US-00003 Ex. Reactants Product Yield S61 0 66% S62 60% S63 61% S64 60% S65 64% S66 0 68% S67 68% S68 70% S69 66%

B: Synthesis of the Complexes

Example Ir(L30)

(18) ##STR00367##

(19) To a well-stirred solution of 6.79 g (10 mmol) S30 in 200 ml of dry benzonitrile are added, at 60° C., 8.27 g (30 mmol) of silver carbonate [534-16-7] and 50 g of glass beads (diameter 3 mm), and the mixture is stirred for 5 min. Then 3.22 g (10 mmol) of tris(acetonitrile)trichloroiridium(III) [85835-70-7] are added, and the reaction mixture is heated to 130° C. on a water separator for 6 h, in the course of which the acetonitrile is distilled off. The mixture is allowed to cool down to 60° C., 2.8 g (12 mmol) of 1,5-cyclooctanediyl(N,N-dimethylamine)(1H-pyrazolato-N.sup.1)borane [125050-95-5] are added, and the mixture is stirred at 60° C. for 16 h. The benzonitrile is removed under reduced pressure, the residue is dissolved in 300 ml of dichloromethane (DCM), and then the DCM is distilled off on a rotary evaporator, with simultaneous dropwise addition of MeOH until the crude product crystallizes. The crude product is filtered off with suction, washed three times with 30 ml each time of MeOH and dried under reduced pressure. The crude product thus obtained is dissolved in 200 ml of dichloromethane and filtered through about 1 kg of silica gel in the form of a dichloromethane slurry (column diameter about 18 cm) with exclusion of air in the dark, leaving dark-coloured components at the start. The core fraction is cut out and concentrated on a rotary evaporator, with simultaneous continuous dropwise addition of MeOH until crystallization.

(20) After removal with suction, washing with a little MeOH and drying under reduced pressure, the orange product is purified further by continuous hot extraction five times with dichloromethane/acetonitrile 1:1 (v/v) (amount initially charged in each case about 200 ml, extraction thimble: standard Soxhlet thimbles made from cellulose from Whatman) with careful exclusion of air and light. The loss into the mother liquor can be adjusted via the ratio of dichloromethane (low boilers and good dissolvers):acetonitrile (high boilers and poor dissolvers). It should typically be 3-6% by weight of the amount used. Hot extraction can also be accomplished using other solvents or solvent mixtures such as toluene, xylene, ethyl acetate, butyl acetate, i-PrOH etc. Finally, the product is fractionally sublimed at 380-440° C. under high vacuum. Yield: 3.82 g (3.6 mmol), 36%. Purity: >99.9% by HPLC.

(21) In an analogous manner, it is possible to prepare the following compounds:

(22) TABLE-US-00004 Ex. Reactants Product Yield Ir(L31) S31 24% Ir(L32) S32 [56953-94-7] 0 35% Ir(L33) S33 32% Ir(L34) S34 [125050-95-5] 74% Ir(L35) S35 [125050-95-5] 34% Ir(L36) S36 [125050-95-5] 33% Ir(L37) S37 [125050-95-5] 29% Ir(L38) S38 [125050-95-5] 34% Ir(L39) S39 [125050-95-5] 37% Ir(L40) S40 [125050-95-5] 0 43% Ir(L41) S41 [125050-95-5] 45% Ir(L42) S42 [125050-95-5] 40%

Example Ir(L60)

(23) ##STR00383##

(24) To a well-stirred solution of 5.92 g (10 mmol) S60 in 200 ml of dry benzonitrile are added, at 60° C., 8.27 g (30 mmol) of silver carbonate [534-16-7] and 50 g of glass beads (diameter 3 mm), and the mixture is stirred for 5 min. Then 3.22 g (10 mmol) of tris(acetonitrile)trichloroiridium(III) [85835-70-7] are added, and the reaction mixture is heated to 130° C. on a water separator for 6 h, in the course of which the acetonitrile is distilled off. The mixture is allowed to cool down to 60° C., 4.98 g (25 mmol) of sodium [dimethylbis(1H-pyrazolato-N.sub.1)]borate [56953-94-7] are added, and the mixture is stirred at 60° C. for 16 h. The benzonitrile is removed under reduced pressure, the residue is dissolved in 300 ml of dichloromethane (DCM), and then the DCM is distilled off on a rotary evaporator, with simultaneous dropwise addition of MeOH until the crude product crystallizes. The crude product is filtered off with suction, washed three times with 30 ml each time of MeOH and then dried under reduced pressure. The crude product thus obtained is purified and sublimed as described in Example Ir(L30). Yield: 3.01 g (3 mmol), 30%. Purity: >99.9% by HPLC.

(25) In an analogous manner, it is possible to prepare the following compounds:

(26) TABLE-US-00005 Ex. Reactants Product Yield Ir(L61) S61 [16453-63-7] 29% Ir(L62) S62 [125050-95-5] 34% Ir(L63) S63 [125050-95-5] 30% Ir(L64) S64 [125050-95-5] 29% Ir(L65) S65 [125050-95-5] 37% Ir(L66) S66 [125050-95-5] 35% Ir(L67) S67 [125050-95-5] 0 27% Ir(L68) S68 [56953-94-7] 31% Ir(L69) S69 [56953-94-7] 33%
Hydrolysis Stability of the Complexes:

(27) For processing from solution (see example: Production of the OLEDs, solution-processed devices), the complexes must have very good hydrolysis stability since the residual water present in the solvent can otherwise result in hydrolytic breakdown. Even hydrolytic breakdown to a slight degree can have a very adverse effect on the component properties of the OLEDs with regard to efficiency and in particular lifetime. To verify hydrolysis stability, 15 mg of the complex are dissolved in 0.75 ml of DMSO-d6, 50 μl of H.sub.2O are added, and the mixture is stored at 60° C. for 8 h. Thereafter, a 1H NMR spectrum (1024 scans) is recorded and compared with the 1H NMR spectrum of the complex in dry DMSO-d6, the solution likewise having been stored at 60° C. for 8 h. Hydrolysis is perceptible by the occurrence of new signals. These can be assigned to the free ligand, hydrolysis products of the ligand and aquo complexes. The results are compiled in Table 1 below.

(28) TABLE-US-00006 TABLE 1 Hydrolysis properties Ex. Complex Observation of hydrolysis H1 Ref-Ir1 yes see (Table 4) H2 Ir(L31) no H3 Ir(L60) no

Example: Production of the OLEDs

1) Vacuum-Processed Devices

(29) OLEDs of the invention and OLEDs according to the prior art are produced by a general method according to WO 2004/058911, which is adapted to the circumstances described here (variation in layer thickness, materials used). In the examples which follow, the results for various OLEDs are presented. Cleaned glass plaques (cleaning in Miele laboratory glass washer, Merck Extran detergent) coated with structured ITO (indium tin oxide) of thickness 50 nm are pretreated with UV ozone for 25 minutes (PR-100 UV ozone generator from UVP) and, within 30 min, for improved processing, coated with 20 nm of PEDOT:PSS (poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate), purchased as CLEVIOS™ P VP Al 4083 from Heraeus Precious Metals GmbH Deutschland, spun on from aqueous solution) and then baked at 180° C. for 10 min. These coated glass plaques form the substrates to which the OLEDs are applied. The OLEDs basically have the following layer structure: substrate/hole injection layer 1 (HIL1) consisting of HTM doped with 5% NDP-9 (commercially available from Novaled), 20 nm/hole transport layer 1 (HTL1) consisting of HTM, 160 nm for blue devices, 220 nm for green/yellow devices/electron blocker layer (EBL)/emission layer (EML)/hole blocker layer (HBL)/electron transport layer (ETL)/optional electron injection layer (EIL) and finally a cathode. The cathode is formed by an aluminium layer of thickness 100 nm.

(30) For vacuum-processed OLEDs, all materials are applied by thermal vapour deposition in a vacuum chamber. In this case, the emission layer always consists of at least one matrix material (host material) and an emitting dopant (emitter) which is added to the matrix material(s) in a particular proportion by volume by co-evaporation. Details given in such a form as M1:M2:Ir(L2) (55%:35%:10%) mean here that the material M1 is present in the layer in a proportion by volume of 55%, M2 in a proportion by volume of 35% and Ir(L1) in a proportion by volume of 10%. Analogously, the electron transport layer may also consist of a mixture of two materials. The exact structure of the OLEDs can be found in Table 2. The materials used for production of the OLEDs are shown in Table 5.

(31) The OLEDs are characterized in a standard manner. For this purpose, the electroluminescence spectra, the current efficiency (measured in cd/A), the power efficiency (measured in Im/W) and the external quantum efficiency (EQE, measured in percent) as a function of luminance, calculated from current-voltage-luminance characteristics (IUL characteristics) assuming Lambertian emission characteristics, and also the lifetime are determined. The electroluminescence spectra are determined at a luminance of 1000 cd/m.sup.2, and the CIE 1931 x and y colour coordinates are calculated therefrom. The lifetime LT80 is defined as the time after which the luminance drops to 80% of the starting luminance in the course of operation with a constant current of 40 mA/cm.sup.2.

(32) Use of Compounds of the Invention as Emitter Materials in Phosphorescent OLEDs

(33) One use of the compounds of the invention is as phosphorescent emitter materials in the emission layer in OLEDs. The results for the OLEDs are collated in Table 3.

(34) TABLE-US-00007 TABLE 2 Structure of the OLEDs EBL EML HBL ETL Ex. thickness thickness thickness thickness D1 EBM1 M1:Ir(L30) ETM1 ETM1:ETM2 10 nm (83%:17%) 10 nm (50%:50%) 30 nm 30 nm D2 EBM1 M1:M2:Ir(L30) ETM1 ETM1:ETM2 10 nm (50%:38%:12%) 10 nm (50%:50%) 30 nm 30 nm D3 EBM1 M1:Ir(L31) ETM1 ETM1:ETM2  5 nm (78%:22%) 10 nm (50%:50%) 30 nm 30 nm D4 EBM2 M1:M2:Ir(L67) ETM1 ETM1:ETM2 10 nm (50%:38%:12%) 10 nm (50%:50%) 30 nm 30 nm D5 EBM2 M1:M2:Ir(L68) ETM1 ETM1:ETM2 10 nm (50%:38%:12%) 10 nm (50%:50%) 30 nm 30 nm

(35) TABLE-US-00008 TABLE 3 Results for the vacuum-processed OLEDs EQE (%) Voltage (V) CIE x/y LT80 (h) Ex. 1000 cd/m.sup.2 1000 cd/m.sup.2 1000 cd/m.sup.2 40 mA/cm.sup.2 D1 23.6 3.1 0.36/0.61 220 D2 23.9 2.9 0.36/0.62 250 D3 21.4 3.3 0.18/0.35 90 D4 23.0 3.0 0.38/0.60 360 D5 26.3 3.1 0.39/0.60 330
Solution-Processed Devices:
From Soluble Functional Materials of Low Molecular Weight

(36) The iridium complexes of the invention may also be processed from solution and lead therein to OLEDs which are much simpler in terms of process technology compared to the vacuum-processed OLEDs, but nevertheless have good properties. The production of such components is based on the production of polymeric light-emitting diodes (PLEDs), which has already been described many times in the literature (for example in WO 2004/037887). The structure is composed of substrate/ITO/hole injection layer (60 nm)/interlayer (20 nm)/emission layer (60 nm)/hole blocker layer (10 nm)/electron transport layer (40 nm)/cathode. For this purpose, substrates from Technoprint (soda-lime glass) are used, to which the ITO structure (indium tin oxide, a transparent conductive anode) is applied. The substrates are cleaned in a cleanroom with DI water and a detergent (Deconex 15 PF) and then activated by a UV/ozone plasma treatment. Thereafter, likewise in a cleanroom, a 20 nm hole injection layer is applied by spin-coating. The required spin rate depends on the degree of dilution and the specific spin-coater geometry. In order to remove residual water from the layer, the substrates are baked on a hotplate at 200° C. for 30 minutes. The interlayer used serves for hole transport. In the present case, an HL-X from Merck is used. The interlayer may alternatively also be replaced by one or more layers which merely have to fulfil the condition of not being leached off again by the subsequent processing step of EML deposition from solution. For production of the emission layer, the triplet emitters of the invention are dissolved together with the matrix materials in toluene or chlorobenzene. The typical solids content of such solutions is between 16 and 25 g/I when, as here, the layer thickness of 60 nm which is typical of a device is to be achieved by means of spin-coating. The solution-processed devices of type 1 contain an emission layer composed of M3:M4:IrL (20%:60%:20%), and those of type 2 contain an emission layer composed of M3:M4:rLa:IrLb (30%:34%:30%:6%); in other words, they contain two different Ir complexes. The emission layer is spun on in an inert gas atmosphere, argon in the present case, and baked at 160° C. for 10 min. Vapour-deposited above the latter are the hole blocker layer (10 nm ETM1) and the electron transport layer (40 nm ETM1 (50%)/ETM2 (50%)) (vapour deposition systems from Lesker or the like, typical vapour deposition pressure 5×10.sup.−6 mbar). Finally, a cathode of aluminium (100 nm) (high-purity metal from Aldrich) is applied by vapour deposition. In order to protect the device from air and air humidity, the device is finally encapsulated and then characterized. The OLED examples cited have not yet been optimized. Table 4 summarizes the data obtained.

(37) TABLE-US-00009 TABLE 4 Results with materials processed from solution Voltage EQE (%) (V) LT50 (h) Emitter 1000 1000 1000 Ex. Device cd/m.sup.2 cd/m.sup.2 CIE x/y cd/m.sup.2 Sol-D1 Ir(L33) 21.3 4.4 0.30/0.63 270000 Type 1 Sol-D2 Ir(L63) 19.8 4.3 0.65/0.34 300000 Ir(L213) Type 2

(38) TABLE-US-00010 TABLE 5 Structural formulae of the materials used 00 01 02