Metal complexes

Abstract

The present invention relates to binuclear metal complexes and electronic devices, in particular organic electroluminescent devices containing said metal complexes of the formula (1): ##STR00001##

Claims

1. A compound of formula (1): ##STR00516## wherein M.sup.1 and M.sup.2 is the same or different and is iridium or rhodium; V is a group of formula (2) or (3): ##STR00517## wherein the dotted bonds in the 1, 3, and 5 positions denote bonds to L.sup.1 and the dotted bonds in the 2, 4, and 6 positions denote bonds to L.sup.2; L.sup.1 and L.sup.2 is the same or different at each instance and is a bidentate monoanionic sub-ligand; A is the same or different in each instance and is —CR═CR—, —C(═O)—NR′—, —C(═O)—O—, —CR.sub.2—CR.sub.2—, —CR.sub.2—O—, or a group of formula (4): ##STR00518## wherein the dotted bond denotes the position of the bond of one bidentate sub-ligand L.sup.1 or L.sup.2 to this structure and * denotes the position of the linkage of the unit of formula (4) to the benzene or cyclohexane group in formula (2) or (3); X.sup.1 is the same or different in each instance and is CR or N or two adjacent X.sup.1 groups together are NR, O, or S, so as to define a five-membered ring, and the remaining X.sup.1 are the same or different in each instance and are CR or N; or two adjacent X.sup.1 groups together are CR or N when one of the X.sup.2 groups in the cycle is N, so as to define a five-membered ring; with the proviso that not more than two adjacent X.sup.1 groups are N; X.sup.2 is C in each instance or one X.sup.2 group is N and the other X.sup.2 group in the same cycle is C; with the proviso that two adjacent X.sup.1 groups together are CR or N when one of the X.sup.2 groups in the cycle is N; R is the same or different in each instance and is H, D, F, Cl, Br, I, N(R.sup.1).sub.2, CN, NO.sub.2, OR.sup.1, SR.sup.1, 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, COO(cation), SO.sub.3(cation), OSO.sub.3(cation), OPO.sub.3(cation).sub.2, O(cation), N(R.sup.1).sub.3(anion), P(R.sup.1).sub.3(anion), a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, wherein the alkyl, alkenyl, or alkynyl group in each case is optionally substituted by one or more R.sup.1 radicals, wherein one or more nonadjacent CH.sub.2 groups is optionally 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 is optionally substituted in each case by one or more R.sup.1 radicals; and wherein two R radicals together optionally define a ring system; R′ is the same or different in each instance and is H, D, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, wherein the alkyl group in each case is optionally substituted by one or more R.sup.1 radicals and wherein one or more nonadjacent CH.sub.2 groups is optionally replaced by Si(R.sup.1).sub.2, or an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and is optionally substituted in each case by one or more R.sup.1 radicals; R.sup.1 is the same or different in each instance and is H, D, F, Cl, Br, I, N(R.sup.2).sub.2, CN, NO.sub.2, OR.sup.2, SR.sup.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, COO(cation), SO.sub.3(cation), OSO.sub.3(cation), OPO.sub.3(cation).sub.2, O(cation), N(R.sup.2).sub.3(anion), P(R.sup.2).sub.3(anion), a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, wherein the alkyl, alkenyl, or alkynyl group in each case is optionally substituted by one or more R.sup.2 radicals, wherein one or more nonadjacent CH.sub.2 groups are optionally 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 is optionally substituted in each case by one or more R.sup.2 radicals; and wherein two or more R.sup.1 radicals together optionally define a ring system; R.sup.2 is the same or different in each instance and is H, D, F, or an aliphatic, aromatic, or heteroaromatic organic radical having 1 to 20 carbon atoms, wherein one or more hydrogen atoms is also optionally replaced by F; cation is the same or different in each instance and is selected from the group consisting of proton, deuteron, alkali metal ions, alkaline earth metal ions, ammonium, tetraalkylammonium, and tetraalkylphosphonium; and anion is the same or different at each instance and is selected from the group consisting of halides, carboxylates R.sup.2—COO.sup.−, cyanide, cyanate, isocyanate, thiocyanate, thioisocyanate, hydroxide, BF.sub.4.sup.−, PF.sub.6.sup.−, B(C.sub.6F.sub.5).sub.4.sup.−, carbonate, and sulfonates.

2. The compound of claim 1, wherein M.sup.1 and M.sup.2 are Ir(III) and the compound is uncharged.

3. The compound of claim 1, wherein the group of formula (4) is selected from the group consisting of structures of Formulae (5) through (29): ##STR00519## ##STR00520## ##STR00521## ##STR00522##

4. The compound of claim 1, wherein the group of formula (2) is selected from the group consisting of Formulae (2a) through (2e) and wherein the group of formula (3) is selected from the group consisting of Formulae (3a) through (3e): ##STR00523## ##STR00524## ##STR00525## ##STR00526##

5. The compound of claim 1, wherein the group of formula (2) is selected from the group consisting of Formula (2a′) and the group of Formula (3) is selected from the group consisting of Formula (3a′): ##STR00527##

6. The compound of claim 1, wherein the group of formula (2) is selected from the group consisting of Formula (2a″) and the group of formula (3) is selected from the group consisting of Formula (3a″): ##STR00528##

7. The compound of claim 1, wherein all three sub-ligands L.sup.1 are the same and all three sub-ligands L.sup.2 are the same, wherein L.sup.1=L.sup.2 or L.sup.1≠L.sup.2.

8. The compound of claim 1, wherein all sub-ligands L.sup.1 and L.sup.2 have one carbon atom and one nitrogen atom or two carbon atoms as coordinating atoms.

9. The compound of claim 1, wherein at least two of sub-ligands L.sup.1 and at least two of sub-ligands L.sup.2 are the same or different in each instance and are selected from the group consisting of structures of Formulae (L-1), (L-2), and (L-3): ##STR00529## wherein the dotted bond denotes the bond of sub-ligand L.sup.1 or L.sup.2 to V; CyC is the same or different in each instance and is a substituted or unsubstituted aryl or heteroaryl group which has 5 to 14 aromatic ring atoms and coordinates to M via a carbon atom and is bonded to CyD via a covalent bond; CyD is the same or different in each instance and is a substituted or unsubstituted heteroaryl group which has 5 to 14 aromatic ring atoms and coordinates to M via a nitrogen atom or via a carbene carbon atom and is bonded to CyC via a covalent bond; and wherein two or more of the substituents together optionally define a ring system.

10. The compound of claim 9, wherein the CyC group is selected from the group consisting of structures of formulae (CyC-1) through (CyC-20) and wherein the CyD group is selected from the group consisting of structures of formulae (CyD-1) through (CyD-14): ##STR00530## ##STR00531## ##STR00532## ##STR00533## ##STR00534## wherein the CyC and CyD groups each bind at the position denoted by # and coordinate to the metal at the position denoted by *, and “o” denotes the possible position of the bond to V if this group is bonded to V; and X is the same or different in each instance and is CR or N, with the proviso that not more than two X per cycle are N; W is NR, O, or S; with the proviso that the X in CyC or CyD via which the sub-ligand is bonded to V is C and V is bonded to this carbon atom.

11. The compound of claim 1, wherein the sub-ligands L.sup.1 and L.sup.2 are the same or different in each instance and are selected from the group consisting of structures of formulae (L-1-1), (L-1-2), (L-2-1) through (L-2-3), and (L-4) through (L-38): ##STR00535## ##STR00536## ##STR00537## ##STR00538## ##STR00539## ##STR00540## ##STR00541## ##STR00542## wherein * denotes the position of coordination to the iridium and “o” denotes the position of the bond to V; X is the same or different in each instance and is CR or N, with the proviso that not more than two X per cycle are N; and wherein the sub-ligands (L-34) through (L-36) each coordinate via the nitrogen atom explicitly shown and the negatively charged oxygen atom and the sub-ligands (L-37) and (L-38) coordinate via the two oxygen atoms.

12. A process for preparing the compound of claim 1 comprising reacting the ligand with metal alkoxides of formula (48), with metal ketoketonates of formula (49), with metal halides of formula (50), or with metal carboxylates of formula (51), or with iridium compounds or rhodium compounds bearing both alkoxide and/or halide and/or hydroxyl radicals and ketoketonate radicals: ##STR00543## wherein M is iridium or rhodium; Hal is F, Cl, Br, or I; and the iridium reactants or rhodium reactants are optionally in the form of their corresponding hydrates.

13. A formulation comprising at least one compound of claim 1 and at least one further compound, wherein the at least one further compound is selected from the group consisting of at least one solvent and at least one matrix material.

14. An electronic device comprising at least one compound of claim 1.

15. The electronic device of claim 14, wherein the electronic device is selected from the group consisting of organic electroluminescent devices, organic integrated circuits, organic field-effect transistors, organic thin-film transistors, organic light-emitting transistors, organic solar cells, organic optical detectors, organic photoreceptors, organic field-quench devices, light-emitting electrochemical cells, oxygen sensors, and organic laser diodes.

16. The electronic device of claim 15, wherein the electronic device is an organic electroluminescent device and wherein the compound of formula (1) is present in the electroluminescent device as an emitting compound in one or more emitting layers.

17. The compound of claim 1, wherein R.sup.2 is a hydrocarbyl radical.

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.

A: Preparation of the Synthons

Example S1

(2) ##STR00356##

(3) A mixture of 28.1 g (100 mmol) of 2-phenyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine [789291-27-7], 28.2 g (100 mmol) of 1-bromo-2-iodobenzene [583-55-1], 31.8 g (300 mmol) of sodium carbonate, 787 mg (3 mmol) of triphenylphosphine, 225 mg (1 mmol) of palladium(II) acetate, 300 ml of toluene, 150 ml of ethanol and 300 ml of water is heated under reflux for 60 h. After cooling, the mixture is extended with 500 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 solvent has been removed, the residue is recrystallized from ethyl acetate/n-heptane or chromatographed on silica gel (toluene/ethyl acetate, 9:1 v/v). Yield: 22.7 g (73 mmol), 73%. Purity: about 97% by .sup.1H NMR.

(4) The compounds which follow can be prepared in an analogous manner, and recrystallization can be accomplished using solvents such as ethyl acetate, cyclohexane, toluene, acetonitrile, n-heptane, ethanol or methanol, for example. It is also possible to use these solvents for hot extraction, or to purify by chromatography on silica gel in an automated column system (Torrent from Axel Semrau).

(5) TABLE-US-00002 Ex. Boronic ester Product Yield  S2 56%  S3 0 72%  S4 71%  S5 70%  S6 69%  S7 67%  S8 0 63%  S9 70% S10 73% S11 72% S12 48% S13 0 65% S14 65% S15 68% S16 77% S17 70% S18 0 66% S19 71% S20 64% S21 58% S22 62% S23 00 75% S24 01 02 78% S25 03 04 82% Bromides known from literature S26 05 S27 06 S28 07

Example S100

(6) ##STR00408##

(7) A mixture of 41.8 g (100 mmol) of 1,3,5-tribromo-2,4,6-trichlorobenzene [13075-02-0], 91.4 g (360 mmol) of bis(pinacolato)diborane [73183-34-3], 88.3 g (900 mmol) of potassium acetate, [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) [72287-26-4], 1300 ml of 1,4-dioxane and 100 g of glass beads (diameter 3 mm) is heated under reflux for 50 h. The dioxane is removed by rotary evaporation on a rotary evaporator, and the black residue is worked up by extraction in a separating funnel with 1000 ml of ethyl acetate and 500 ml of water. The organic phase is washed once with 300 ml of water and once with 150 ml of saturated sodium chloride solution, and filtered through a silica gel bed. The silica gel is washed twice with 250 ml each time of ethyl acetate. The filtrate is dried over sodium sulfate and concentrated. The residue is chromatographed with heptane/ethyl acetate on silica gel. Yield: 10.6 g (19 mmol), 19%. Purity: about 98% by .sup.1H NMR.

Example S200

(8) ##STR00409##

(9) a) S200a—Suzuki Coupling:

(10) ##STR00410##

(11) A mixture of 55.9 g (100 mmol) of S100, 102.4 g (330 mmol) of S1, 63.3 g (600 mmol) of sodium carbonate, 4.6 g (4 mmol) of tetrakis(triphenylphosphine)palladium(0), 1500 ml of 1,2-dimethoxyethane and 750 ml of water is heated under reflux for 48 h. After cooling, the precipitated solids are filtered off with suction and washed twice with 20 ml of ethanol. The solids are dissolved in 500 ml of dichloromethane and filtered through a Celite bed. The filtrate is concentrated down to 100 ml, then 400 ml of ethanol are added and the precipitated solids are filtered off with suction. The crude product is recrystallized once from ethyl acetate. Yield: 24.3 g (28 mmol), 28%. Purity: about 96% by .sup.1H NMR.

(12) b) S200—Borylation:

(13) A well-stirred mixture of 17.4 g (20 mmol) of S200a, 16.8 g (66 mmol) of bis(pinacolato)diborane [73183-34-3], 19.6 g (120 mmol) of potassium acetate (anhydrous), 50 g of glass beads (diameter 3 mm), 1027 mg (2.4 mmol) of SPhos [657408-07-6], 270 g (1.2 mmol) of palladium(II) acetate and 300 ml of 1,4-dioxane is heated under reflux for 16 h. The dioxane is removed by rotary evaporation on a rotary evaporator, and the black residue is worked up by extraction in a separating funnel with 300 ml of toluene and 200 ml of water. The organic phase is washed once with 100 ml of water and once with 50 ml of saturated sodium chloride solution, and filtered through a Celite bed. The filtrate is dried over sodium sulfate and then concentrated to dryness. The residue is chromatographed with dichloromethane/ethyl acetate on silica gel (Torrent automated column system from A. Semrau). Yield: 13.8 g (12 mmol), 60%. Purity: about 95% by .sup.1H NMR.

(14) The compounds which follow can be prepared in an analogous manner, and recrystallization can be accomplished using solvents such as ethyl acetate, cyclohexane, toluene, acetonitrile, n-heptane, ethanol or methanol, for example. It is also possible to use these solvents for hot extraction, or to purify purified by chromatography on silica gel in an automated column system (Torrent from Axel Semrau).

(15) TABLE-US-00003 Ex. Bromide Yield S201  S2 16% S202  S3 19% S203  S4 15% S204  S5 17% S205  S6 22% S206  S7 20% S207  S8 18% S208  S9 17% S209 S10 0 22% S210 S11 23% S211 S12 21% S212 S13 20% S213 S14 17% S214 S15 21% S215 S16 20% S216 S17 18% S217 S18 20% S218 S19 20% S219 S20 0 23% S220 S21 17% S221 S22 19% S222 S23 19% S223 S24 22% S224 S25 20%

B: Synthesis of the Ligands

Example L1

(16) ##STR00436##

(17) A mixture of 11.4 g (10.0 mmol) of S200, 12.4 g (40.0 mmol) of S1, 20.7 g (90 mmol) of potassium phosphate monohydrate, 507 mg (0.6 mmol) of XPhos palladacycle Gen.3 [1445085-55-1], 200 ml of tetrahydrofuran and 100 ml of water is heated under reflux for 20 h. After cooling, the precipitated solids are filtered off with suction and washed twice with 30 ml each time of water and twice with 30 ml each time of ethanol. The solids are dissolved in 200 ml of dichloromethane (DCM) and filtered through a silica gel bed in the form of a DCM slurry. The filtrate is concentrated, and the residue is chromatographed with dichloromethane/ethyl acetate on silica gel (Torrent automated column system from A. Semrau). Yield: 2.5 g (2.2 mmol) 22%. Purity: about 95% by .sup.1H NMR.

(18) The compounds which follow can be prepared in an analogous manner, and recrystallization can be accomplished using solvents such as ethyl acetate, cyclohexane, toluene, acetonitrile, n-heptane, ethanol or methanol, for example. It is also possible to use these solvents for hot extraction, to purify purified by chromatography on silica gel in an automated column system (Torrent from Axel Semrau).

(19) TABLE-US-00004 Ex. Reactants Product Yield L2 S200 S3 26% L3 S201 S2 25% L4 S202 S3 27% L5 S203 S4 0 20% L6 S204 S5 22% L7 S205 S5 25% L8 S206 S10 23% L9 S207 S5 19% L10 S208 S4 26% L11 S209 S4 21% L12 S210 S4 20% L13 S211 S5 22% L14 S212 S6 20% L15 S213 S17 0 26% L16 S214 S5 25% L17 S215 S6 23% L18 S216 S4 19% L19 S217 S5 20% L20 S218 S15 23% L21 S219 S4 24% L22 S220 S5 21% L23 S221 S4 20% L24 S222 S9 24% L25 S223 S9 0 25% L26 S224 S25 18% L27 S204 S26 21% L28 S205 S27 23% L29 S205 S28 20%

C: Synthesis of the Metal Complexes

(20) Ir.sub.2(L1)

(21) ##STR00465##

(22) A mixture of 14.6 g (10 mmol) of ligand L1, 9.9 g (20 mmol) of trisacetylacetonatoiridium(III) [15635-87-7] and 150 g of hydroquinone [123-31-9] is initially charged in a 1000 ml two-neck round-bottom flask with a glass-sheathed magnetic bar. The flask is provided with a water separator (for media of lower density than water) and an air condenser with argon blanketing and placed into a metal heating bath. The apparatus is purged with argon from the top via the argon blanketing system for 15 min, allowing the argon to flow out of the side neck of the two-neck flask. Through the side neck of the two-neck flask, a glass-sheathed Pt-100 thermocouple is introduced into the flask and the end is positioned just above the magnetic stirrer bar. Then the apparatus is thermally insulated with several loose windings of domestic aluminum foil, the insulation being run up to the middle of the riser tube of the water separator. Then the apparatus is heated rapidly with a heated laboratory stirrer system to 250° C., measured with the Pt-100 thermal sensor which dips into the molten stirred reaction mixture. Over the next 2 h, the reaction mixture is kept at 250° C., in the course of which a small amount of condensate is distilled off and collects in the water separator. The reaction mixture is left to cool down to 190° C., then 100 ml of ethylene glycol are added dropwise. The mixture is left to cool down further than to 80° C., then 500 ml of methanol are added dropwise and the mixture is heated at reflux for 1 h. The suspension thus obtained is filtered through a double-ended frit, and the solids are washed twice with 50 ml of methanol and then dried under reduced pressure. Further purification is effected by hot extraction five times with dichloromethane (amount initially charged in each case about 350 ml, extraction thimble: standard Soxhlet thimbles made from cellulose from Whatman) with careful exclusion of air and light. Finally, heat treatment is effected at 300° C. under high vacuum. Yield: 10.5 g (5.7 mmol), 57%. Purity: >99.9% by .sup.1H NMR.

(23) ΔΔ and ∧∧ isomers are obtained, which are enantiomeric and form a racemate. Racemate separation into the two enantiomers is possible by standard methods, such as chromatography on chiral media or fractional crystallization, for example with chiral acids (e.g. camphorsulfonic acid).

(24) The compounds shown below can be synthesized in an analogous manner. The compounds can in principle be purified by chromatography (typically use of an automated column system (Torrent from Axel Semrau), recrystallization or hot extraction). Residual solvents can be removed by heat treatment under high vacuum at typically 250-330° C.

(25) TABLE-US-00005 Product Ex. Ligand Hot extractant Yield Ir.sub.2(L2) L2 55% Rh.sub.2(L2) L2 40% Ir.sub.2(L3) L3 Ir.sub.2(L3) toluene Ir.sub.2(L4) L4 60% Ir.sub.2(L5) L5 Ir.sub.2(L5) 57% o-xylene Ir.sub.2(L6) L6 Ir.sub.2(L6) 53% toluene Ir.sub.2(L7) L7 61% Ir.sub.2(L8) L8 Ir.sub.2(L8) 55% toluene Ir.sub.2(L9) L9 Ir.sub.2(L9) 57% toluene Ir.sub.2(L10) L10 Ir.sub.2(L10) 51% o-xylene Ir.sub.2(L11) L11 Ir.sub.2(L11) 49% toluene Ir.sub.2(L12) L12 0 36% Ir.sub.2(L13) L13 63% Ir.sub.2(L14) L14 Ir.sub.2(L14) 57% toluene Ir.sub.2(L15) L15 Ir.sub.2(L15) 54% toluene Ir.sub.2(L16) L16 50% Ir.sub.2(L17) L17 52% Ir.sub.2(L18) L18 Ir.sub.2(L18) 57% toluene Ir.sub.2(L19) L19 Ir.sub.2(L19) 58% toluene Ir.sub.2(L20) L20 53% Ir.sub.2(L21) L21 Ir.sub.2(L21) 53% toluene Ir.sub.2(L22) L22 Ir.sub.2(L22) 59% o-xylene Ir.sub.2(L23) L23 57% Ir.sub.2(L24) L24 Ir.sub.2(L24) 54% toluene Ir.sub.2(L25) L25 Ir.sub.2(L25) 48% toluene Ir.sub.2(L26) L26 Ir.sub.2(L26) 51% o-xylene Ir.sub.2(L27) L27 Ir.sub.2(L27) 56% toluene Ir.sub.2(L28) L28 Ir.sub.2(L28) 50% chlorobenzene Ir.sub.2(L29) L29 Ir.sub.2(L29) 61% butyl acetate * if different from standard method.

(26) In an analogous manner, by the addition of first 10 mmol of Ir(acac).sub.3 and conducting the reaction at 250° C. for 1 h and then addition of 10 mmol of Rh(acac).sub.3 [14284-92-5] and continuing the reaction at 250° C. for 1 h and subsequent workup and purification as described above, it is possible to obtain mixed metallic Rh—Ir complexes.

(27) TABLE-US-00006 Rh-Ir(L4) L4 1) 10 mmol lr(acac).sub.3 [15635-87-7] 2) 10 mmol Rh(acac).sub.3 [14284-92-5] 61%

D: Functionalization of the Metal Complexes

(28) 1) Halogenation of the Iridium Complexes:

(29) To a solution or suspension of 1 mmol of a complex bearing A×C—H groups (with A=1-6) in the para position to the iridium in the bidentate sub-ligand in 200 ml to 2000 ml of dichloromethane according to the solubility of the metal complexes is added, in the dark and with exclusion of air, at −30 to +30° C., A×1.05 mmol of N-halosuccinimide (halogen: Cl, Br, I), and the mixture is stirred for 20 h. Complexes of sparing solubility in DCM may also be converted in other solvents (TCE, THF, DMF, chlorobenzene, etc.) and at elevated temperature. Subsequently, the solvent is substantially removed under reduced pressure. The residue is extracted by boiling with 30-100 ml of methanol, and the solids are filtered off with suction, washed three times with 20 ml of methanol and then dried under reduced pressure. This gives the iridium complexes brominated/halogenated in the para position to the iridium. Complexes having a HOMO (CV) of about −5.1 to −5.0 eV and of smaller magnitude have a tendency to oxidation (Ir(III).fwdarw.Ir(IV)), the oxidizing agent being bromine released from NBS. This oxidation reaction is apparent by a distinct green hue or brown hue in the otherwise yellow to red solutions/suspensions of the emitters. In such cases, 1-2 further equivalents of NBS are added. For workup, 30-100 ml of methanol and 0.5 ml of hydrazine hydrate as reducing agent are added, which causes the green or brown solution or suspension to turn yellow or red (reduction of Ir(IV).fwdarw.Ir(III)). Then the solvent is substantially drawn off under reduced pressure, 50 ml of methanol are added, and the solids are filtered off with suction, washed three times with 20 ml each time of methanol and dried under reduced pressure.

(30) Substoichiometric brominations, for example mono-, dibrominations etc., of complexes having 6 C—H groups para position the iridium atoms usually proceed less selectively than the stoichiometric brominations. The crude products of these brominations can be separated by chromatography (CombiFlash Torrent from A. Semrau).

Synthesis of Ir.SUB.2.L1-6Br

(31) ##STR00477##

(32) To a suspension of 1.61 g (1.0 mmol) of Ir.sub.2(L1) in 200 ml of DCM are added 1.16 g (6.5 mmol) of N-bromosuccinimide (NBS) all at once and then the mixture is stirred for 20 h. 0.5 ml of hydrazine hydrate in 30 ml of MeOH is added. After removing about 180 ml of the solvent under reduced pressure, the yellow solids are filtered off with suction, washed three times with about 20 ml of methanol and then dried under reduced pressure. Yield: 2.02 g (0.97 mmol), 97%; purity: >99.5% by NMR.

(33) The following compounds can be synthesized in an analogous manner:

(34) TABLE-US-00007 Ex. Reactants Product Yield Ir.sub.2(L2-Br6) Ir.sub.2(L2) 95% Ir.sub.2(L4-Br6) Ir.sub.2(L4) 95% Ir.sub.2(L6-Br6) Ir.sub.2(L6) 0 96% Ir.sub.2(L7-Br6) Ir.sub.2(L7) 95% Ir.sub.2(L10-Br3) Ir.sub.2(L10) 3.3 eq NBS 97% Ir.sub.2(L14-Br6) Ir.sub.2(L14) 94% Ir.sub.2(L16-Br6) Ir.sub.2(L16) 89% Ir.sub.2(L17-Br3) Ir.sub.2(L17) 3.3 eq NBS 94% Ir.sub.2(L18-Br6) Ir.sub.2(L18) 96% Ir.sub.2(L22-Br3) Ir.sub.2(L22) 3.3 eq NBS 91% Ir.sub.2(L28-Br6) Ir.sub.2(L28) 88% Ir.sub.2(L29-Br6) Ir.sub.2(L29) 94

(35) 2) Suzuki Coupling with the Brominated Iridium Complexes:

(36) Variant A, Biphasic Reaction Mixture

(37) To a suspension of 1 mmol of a brominated complex, 1.2-2 mmol of boronic acid or boronic ester per Br function and 6-10 mmol of tripotassium phosphate in a mixture of 50 ml of toluene, 20 ml of dioxane and 50 ml of water are added 0.36 mmol of tri-o-tolylphosphine and then 0.06 mmol of palladium(II) acetate, and the mixture is heated under reflux for 16 h. After cooling, 50 ml of water and 50 ml of toluene are added, the aqueous phase is removed, and the organic phase is washed three times with 50 ml of water and once with 50 ml of saturated sodium chloride solution and dried over magnesium sulfate. The mixture is filtered through a Celite bed in the form of a toluene slurry and washed through with toluene, the toluene is removed almost completely under reduced pressure, 50 ml of methanol are added, and the precipitated crude product is filtered off with suction, washed three times with 30 ml each time of methanol and dried under reduced pressure. The crude product is columned on silica gel in an automated column system (Torrent from Semrau). Subsequently, the complex is purified further by hot extraction in solvents such as ethyl acetate, toluene, dioxane, acetonitrile, cyclohexane, ortho- or para-xylene, n-butyl acetate, chlorobenzene etc. Alternatively, it is possible to recrystallize from these solvents and high boilers such as dimethylformamide, dimethyl sulfoxide or mesitylene. The metal complex is finally heat-treated or sublimed. The heat treatment is effected under high vacuum (p about 10.sup.−6 mbar) within the temperature range of about 200-300° C.

(38) Variant B, Monophasic Reaction Mixture:

(39) To a suspension of 1 mmol of a brominated complex, 1.2-2 mmol of boronic acid or boronic ester per Br function and 2-4 mmol of the base per Br function (potassium fluoride, tripotassium phosphate (anhydrous, monohydrate or trihydrate), potassium carbonate, cesium carbonate etc.) and 10 g of glass beads (diameter 3 mm) in 30-50 ml of an aprotic solvent (THF, dioxane, xylene, mesitylene, dimethylacetamide, NMP, DMSO, etc.) is added 0.01 mmol per Br function of tetrakis(triphenylphosphine)palladium(0) [14221-01-3], and the mixture is heated under reflux for 24 h. Alternatively, it is possible to use other phosphines such as triphenylphosphine, tri-tert-butylphosphine, SPhos, XPhos, RuPhos, XanthPhos, etc. in combination with Pd(OAc).sub.2, the preferred phosphine:palladium ratio in the case of these phosphines being 3:1 to 1.2:1. The solvent is removed under reduced pressure, the product is taken up in a suitable solvent (toluene, dichloromethane, ethyl acetate, etc.) and purification is effected as described in Variant A.

(40) In the case of sparingly soluble reactant complexes, it may be advantageous first to conduct the Suzuki coupling by variant B and to subject the crude product obtained to another Suzuki coupling by variant A in order to achieve maximum conversion. After the crude product has been isolated, trace contaminations by remaining bromine can be removed by boiling the crude product in 100 ml of toluene with addition of 10 mg of palladium(II) acetate and 1 ml of hydrazine hydrate for 16 h. Thereafter, the crude product is purified as described above.

Synthesis of Ir.SUB.2.1

(41) ##STR00490##

(42) Variant B:

(43) Use of 2.08 g (1.0 mmol) of Ir(L1-6Br) and 2.31 g (12.0 mmol) of [4-(2,2-dimethylpropyl)phenyl]boronic acid [186498-04-4], 4.15 g (18.0 mmol) of tripotassium phosphate monohydrate, 70 mg (0.06 mmol) of tetrakis(triphenylphosphine)palladium(0), 50 ml of dry dimethyl sulfoxide, 100° C., 16 h. Chromatographic separation on silica gel with DCM/n-heptane (automated column system, Torrent from Axel Semrau), followed by hot extraction five times with toluene. Yield: 1.44 g (0.53 mmol), 53%. Purity: about 99.9% by HPLC.

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

(45) TABLE-US-00008 Reactants Product Ex. Variant Hot extraction solvent Yield Ir.sub.22 Ir.sub.2(L2-Br6) 912844-88-4 B 48% Ir.sub.23 Ir.sub.2(L4-Br6) 912844-88-4 B, then A, then debromination with hydrazine hydrate 44% Ir.sub.24 Ir.sub.2(L6-Br6) 627526-15-2 B 53% Ir.sub.25 Ir.sub.2(L7-Br6) 888330-89-0 B, then A, then debromination with hydrazine hydrate 49% Ir.sub.26 Ir.sub.2(L10-Br3) 6 eq 1257248-43-3 B 51% Ir.sub.27 Ir.sub.2(L14-Br6) 796071-96-0 B 55% Ir.sub.28 Ir.sub.2(L16-Br6) 84110-40-7 A S-Phos / Pd(ac).sub.2 2/1 47% Ir.sub.29 Ir.sub.2(L17-Br3) 6 eq 1126522-69-7 A 54% Ir.sub.210 Ir.sub.2(L18-Br6) 186498-04-4 B 49% Ir.sub.211 Ir.sub.2(L22-Br3) 6 eq 912844-88-4 B 00 55% Ir.sub.212 Ir.sub.2(L28-Br6) 912844-88-4 B, then A, then debromination with hydrazine hydrate 01 57% Ir.sub.214 Ir.sub.2(L29-Br6) 98-80-6 B, then A, then debromination with hydrazine hydrate 02 51% Ir.sub.215 Ir.sub.2(L29-Br6) 1126522-69-7 B, then A, then debromination with hydrazine hydrate 03 49%

Example: Thermal and Photophysical Properties and Oxidation and Reduction Potentials

(46) Table 1 summarizes the thermal and photochemical properties and oxidation potentials of the comparative materials and the selected materials of the invention. The compounds of the invention have improved thermal stability and photostability compared to the non-polypodal materials according to the prior art. While non-polypodal materials according to the prior art exhibit brown discoloration and ashing after thermal storage at 380° C. for 7 days and secondary components in the region of >2 mol % can be detected in the .sup.1H NMR, the complexes of the invention are inert under these conditions. In addition, the compounds of the invention have very good photostability in anhydrous C.sub.6D.sub.6 solution under irradiation with light of wavelength about 455 nm. More particularly, in contrast to non-polypodal prior art complexes containing bidentate ligands, no facial-meridional isomerization is detectable in the .sup.1H NMR. As can be inferred from Table 1, the compounds of the invention in solution show universally very high photoluminescence quantum efficiencies (PLQE).

(47) TABLE-US-00009 TABLE 1 PL- max Therm. [nm]. stability HOMO FWHM PLQE Decay time Photochem. Complex [eV] [nm] Solvent τ [μs] stab. Comparative examples, for structures see device examples, table 2 Ref1 −5.10 509 0.97 1.3 decomp. IrPPy 67 toluene decomp. Ref2 −5.12 520 0.98 1.6 no decomp. 64 toluene no decomp. Inventive examples Ir.sub.2(L1) −5.17 540 0.98 1.2 no decomp. 65 toluene no decomp. Ir.sub.2(L4) −5.02 528 0.99 1.1 no decomp. 62 toluene no decomp. Ir.sub.23 −5.01 527 0.97 1.2 no decomp. 56 toluene no decomp. Legend: Therm. stab. (thermal stability): Storage in ampoules closed by fusion under reduced pressure, 7 days at 380° C. Visual assessment for color change/brown discoloration/ashing and analysis by means of .sup.1H NMR spectroscopy. Photo. stab. (photochemical stability): Irradiation of about 1 mmolar solutions in anhydrous C.sub.6D.sub.6 (degassed NMR tubes closed by fusion) with blue light (about 455 nm, 1.2 W Lumispot from Dialight Corporation, USA) at room temperature. PL-max.: Maximum of the PL spectrum in [nm] of a degassed about 10.sup.−5 molar solution at RT, excitation wavelength 370 nm, for solvent see PLQE column. FWHM: Half-height width of the PL spectrum in [nm] at RT. PLQE.: Absolute photoluminescence quantum efficiency of a degassed, about 10.sup.−5 molar solution in the solvent specified measured at RT as an absolute value via Ulbricht sphere. Decay time: T.sub.1 lifetime measurements are determined by time-correlated single photon counting of a degassed 10.sup.−5 molar solution in toluene at room temperature. HOMO, LUMO: in [eV] vs. vacuum, determined in dichloromethane solution (oxidation) or THF (reduction) with internal ferrocene reference (−4.8 eV vs. vacuum).

DEVICE EXAMPLES

(48) Production of the OLEDs

(49) The complexes of the invention can be processed from solution and lead, compared to vacuum-processed OLEDs, to more easily producible OLEDs having properties that are nevertheless good. There are already many descriptions of the production of completely solution-based OLEDs in the literature, for example in WO 2004/037887. There have likewise been many previous descriptions of the production of vacuum-based OLEDs, including in WO 2004/058911. In the examples discussed hereinafter, layers applied in a solution-based and vacuum-based manner are combined within an OLED, and so the processing up to and including the emission layer is effected from solution and the subsequent layers (hole blocker layer and electron transport layer) from vacuum. For this purpose, the previously described general methods are matched to the circumstances described here (layer thickness variation, materials) and combined as follows. The general structure is as follows: substrate/ITO (50 nm)/hole injection layer (HIL)/hole transport layer (HTL)/emission layer (EML)/hole blocker layer (HBL)/electron transport layer (ETL)/cathode (aluminum, 100 nm). Substrates used are glass plates coated with structured ITO (indium tin oxide) of thickness 50 nm. For better processing, they are coated with PEDOT:PSS (poly(3,4-ethylenedioxy-2,5-thiophene) polystyrenesulfonate, purchased from Heraeus Precious Metals GmbH & Co. KG, Germany). PEDOT:PSS is spun on from water under air and subsequently baked under air at 180° C. for 10 minutes in order to remove residual water. The hole transport layer and the emission layer are applied to these coated glass plates. The hole transport layer used is crosslinkable. A polymer of the structures shown below is used, which can be synthesized according to WO 2010/097155 or WO 2013/156130:

(50) ##STR00504##

(51) The hole transport polymer is dissolved in toluene. The typical solids content of such solutions is about 5 g/I when, as here, the layer thickness of 20 nm which is typical of a device is to be achieved by means of spin-coating. The layers are spun on in an inert gas atmosphere, argon in the present case, and baked at 180° C. for 60 minutes.

(52) The emission layer is always composed of at least one matrix material (host material) and an emitting dopant (emitter). In addition, mixtures of a plurality of matrix materials and co-dopants may occur. Details given in such a form as TMM-A (92%):dopant (8%) mean here that the material TMM-A is present in the emission layer in a proportion by weight of 92% and dopant in a proportion by weight of 8%. The mixture for the emission layer is dissolved in toluene or optionally chlorobenzene. The typical solids content of such solutions is about 17 g/l 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 layers are spun on in an inert gas atmosphere, argon in the present case, and baked at 150° C. for 10 minutes. The materials used in the present case are shown in Table 2.

(53) TABLE-US-00010 TABLE 2 EML materials used 05 A-1 06 A-2 07 B-1 08 G-1 09 Ref1 0 Ref2 G-2 R-1 R-2

(54) The materials for the hole blocker layer and electron transport layer are applied by thermal vapor deposition in a vacuum chamber. The electron transport layer, for example, may consist of more than one material, the materials being added to one another by co-evaporation in a particular proportion by volume. Details given in such a form as ETM1:ETM2 (50%:50%) mean here that the ETM1 and ETM2 materials are present in the layer in a proportion by volume of 50% each. The materials used in the present case are shown in Table 3.

(55) TABLE-US-00011 TABLE 3 HBL and ETL materials used ETM1 ETM2

(56) The cathode is formed by the thermal evaporation of a 100 nm aluminum layer. The OLEDs are characterized in a standard manner. For this purpose, the electroluminescence spectra, current-voltage-luminance characteristics (IUL characteristics) assuming Lambertian radiation characteristics and the operating lifetime are determined. The IUL characteristics are used to determine parameters such as the operating voltage (in V) and the efficiency (cd/A) at a particular brightness. The electroluminescence spectra are measured at a luminance of 1000 cd/m.sup.2, and the CIE 1931 x and y color coordinates are calculated therefrom. The lifetime is defined as the time after which the luminance has fallen from a particular starting luminance to a certain proportion. The figure LT90 means that the lifetime specified is the time at which the luminance has dropped to 90% of the starting luminance, i.e. from, for example, 1000 cd/m.sup.2 to 900 cd/m.sup.2. According to the emission color, different starting brightnesses are chosen. The values for the lifetime can be converted to a figure for other starting luminances with the aid of conversion formulae known to those skilled in the art. In this context, the lifetime for a starting luminance of 1000 cd/m.sup.2 is a standard figure. Alternatively, lifetimes can be determined for a particular initial current, e.g. 60 mA/cm.sup.2. The EML mixtures and structures of the OLED components examined are shown in tables 4 and 5. The corresponding results can be found in table 6.

(57) TABLE-US-00012 TABLE 4 EML mixtures of the OLED components examined Matrix Co-matrix Co-dopant A B C Dopant D Ex. material % material % material % material % red VR1 A-2 30 B-1 47 G-1 17 R-1 6 VR2 A-2 30 B-1 34 G-1 30 R-2 6 ER1 A-2 30 B-1 47 Ir.sub.21 17 R-1 6 ER2 A-2 30 B-1 34 Ir.sub.21 30 R-2 6 green-yellow VG1 A-2 20 B-1 60 — — G1 20 VG2 A-2 20 B-1 60 — — G2 20 EG1 A-2 20 B-1 60 — — Ir.sub.2(L5) 20 EG2 A-2 20 B-1 60 — — Ir.sub.2(L27) 20 EG3 A-2 20 B-1 60 — — Ir.sub.21 20 EG4 A-2 20 B-1 60 — — Ir.sub.23 20 EG5 A-2 20 B-1 60 — — Ir.sub.24 20 EG6 A-1 20 B-1 60 — — Ir.sub.26 20 EG7 A-1 20 B-1 60 — — Ir.sub.29 20 EG8 A-1 20 B-1 60 — — Ir.sub.212 20

(58) TABLE-US-00013 TABLE 5 Structure of the OLED components examined HIL HTL (thick- (thick- EML HBL ETL Ex. ness) ness) (thickness) (thickness) (thickness) red VR1 PEDOT HTL2 60 nm ETM-1 ETM-1 (50%):ETM-2 (60 nm) (20 nm) (10 nm) (50%) (40 nm) VR2 PEDOT HTL2 60 nm ETM-1 ETM-1 (50%):ETM-2 (60 nm) (20 nm) (10 nm) (50%) (40 nm) ER1 PEDOT HTL2 60 nm ETM-1 ETM-1 (50%):ETM-2 (60 nm) (20 nm) (10 nm) (50%) (40 nm) ER2 PEDOT HTL2 60 nm ETM-1 ETM-1 (50%):ETM-2 (60 nm) (20 nm) (10 nm) (50%) (40 nm) yellow-green V PEDOT HTL2 60 nm ETM-1 ETM-1 (50%):ETM-2 G1 (60 nm) (20 nm) (10 nm) (50%) (40 nm) V PEDOT HTL2 60 nm ETM-1 ETM-1 (50%):ETM-2 G2 (60 nm) (20 nm) (10 nm) (50%) (40 nm) E PEDOT HTL2 60 nm ETM-1 ETM-1 (50%):ETM-2 G1 (60 nm) (20 nm) (10 nm) (50%) (40 nm) E PEDOT HTL2 60 nm ETM-1 ETM-1 (50%):ETM-2 G2 (60 nm) (20 nm) (10 nm) (50%) (40 nm) E PEDOT HTL2 60 nm ETM-1 ETM-1 (50%):ETM-2 G3 (60 nm) (20 nm) (10 nm) (50%) (40 nm) E PEDOT HTL2 60 nm ETM-1 ETM-1 (50%):ETM-2 G4 (60 nm) (20 nm) (10 nm) (50%) (40 nm) E PEDOT HTL2 60 nm ETM-1 ETM-1 (50%):ETM-2 G5 (60 nm) (20 nm) (10 nm) (50%) (40 nm) E PEDOT HTL2 60 nm ETM-1 ETM-1 (50%):ETM-2 G6 (60 nm) (20 nm) (10 nm) (50%) (40 nm) E PEDOT HTL2 60 nm ETM-1 ETM-1 (50%):ETM-2 G7 (60 nm) (20 nm) (10 nm) (50%) (40 nm) E PEDOT HTL2 60 nm ETM-1 ETM-1 (50%):ETM-2 G8 (60 nm) (20 nm) (10 nm) (50%) (40 nm)

(59) TABLE-US-00014 TABLE 6 Results for solution-processed OLEDs (at a brightness of 1000 cd/m.sup.2) red EQE LT90 Ex. [%] CIE x CIE y @60 mA/cm.sup.2 VR1 16.2 0.66 0.34 276 VR2 18.2 0.64 0.36 298 ER1 16.8 0.66 0.34 300 ER2 19.0 0.66 0.34 346 yellow-green EQE LT90 Ex. [%] CIE x CIE y @1000 cd/m.sup.2 VG1 19.9 0.32 0.63 20000 VG2 21.5 0.32 0.65 28000 EG1 21.3 0.49 0.50 55000 EG2 20.6 0.34 0.63 33000 EG3 20.8 0.38 0.61 38000 EG4 21.8 0.33 0.64 32000 EG5 22.0 0.33 0.63 33000 EG6 21.7 0.45 0.48 47000 EG7 21.3 0.34 0.63 35000 EG8 22.3 0.35 0.62 34000

(60) The following inventive compounds Ir.sub.2(L2), Ir.sub.2(L3), Ir.sub.2(L4), Ir.sub.2(L6), Ir.sub.2(L7), Ir.sub.2(L8), Ir.sub.2(L9), Ir.sub.2(L10), Ir.sub.2(L11), Ir.sub.2(L12), Ir.sub.2(L13), Ir.sub.2(L14), Ir.sub.2(L15), Ir.sub.2(L16), Ir.sub.2(L17), Ir.sub.2(L18), Ir.sub.2(L19), Ir.sub.2(L20), Ir.sub.2(L21), Ir.sub.2(L22), Ir.sub.2(L23), Ir.sub.2(L24), Ir.sub.2(L25), Ir.sub.2(L26), Ir.sub.2(L27), Ir.sub.2(L28), Ir.sub.2(L29), Rh—Ir(L4), Ir.sub.22, Ir.sub.24, Ir.sub.25, Ir.sub.27, Ir.sub.28, Ir.sub.29, Ir.sub.210, Ir.sub.211, Ir.sub.213, Ir.sub.214, Ir.sub.215 can likewise be incorporated in OLED devices and show yellow-green or red electroluminescence, good efficiencies and long lifetimes.