Metal complexes

Abstract

The present invention relates to metal complexes, to compositions and formulations comprising these complexes, and to devices comprising the complexes or compositions.

Claims

1. A composition comprising a compound of formula (1): ##STR00033## wherein M is Li; X is O; R is a group of formulae (R-1) through (R-33), wherein the dashed line denotes the bond to the quinoline ring of the compound of formula (1): ##STR00034## ##STR00035## ##STR00036## n is 1; wherein R is bonded to the quinoline ring at position 2; and an electron-transport material comprising at least one triazine.

2. The composition of claim 1, wherein the compound is a compound of formulae (A-2) through (A-4): ##STR00037##

3. A composition comprising one or more compounds of claim 1 and at least one additional functional material selected from the group consisting of fluorescent emitters, phosphorescent emitters, host materials, matrix materials, electron-transport materials, electron-injection materials, hole-conductor materials, hole-injection materials, electron-blocking materials, hole-blocking materials, and n-dopants.

4. The composition of claim 3, wherein the additional functional material is an electron-transport material selected from the group consisting of pyridines, pyrimidines, pyridazines, pyrazines, oxadiazoles, oxazoles, lactams, quinolines, quinoxalines, anthracenes, benzanthracenes, pyrenes, perylenes, benzimidazoles, triazines, ketones, phosphine oxides, and phenazines.

5. The composition of claim 3, wherein the additional functional material is an electron-transport material which comprises a compound of formula (2): ##STR00038## wherein: R.sup.1 is on each occurrence, identically or differently, H, D, F, Cl, Br, I, CHO, N(R.sup.2).sub.2, N(Ar.sup.1).sub.2, B(Ar.sup.1).sub.2, C(═O)Ar.sup.1, P(═O)(Ar.sup.1).sub.2, S(═O)Ar.sup.1, S(═O).sub.2Ar.sup.1, CR.sup.2═CR.sup.2Ar.sup.1, CN, NO.sub.2, Si(R.sup.2).sub.3, B(OR.sup.2).sub.2, B(R.sup.2).sub.2, B(N(R.sup.2).sub.2).sub.2, OSO.sub.2R.sup.2, a straight-chain alkyl, alkenyl, alkynyl, alkoxy, or thioalkoxy group having 1 to 40 C atoms or a branched or cyclic alkyl, alkenyl, alkynyl, alkoxy, or thioalkoxy group having 3 to 40 C atoms, each of which is optionally substituted by one or more radicals R.sup.2, wherein one or more non-adjacent CH.sub.2 groups are optionally replaced by R.sup.2C═CR.sup.2, C≡C, Si(R.sup.2).sub.2, Ge(R.sup.2).sub.2, Sn(R.sup.2).sub.2, C═O, C═S, C═Se, C═NR.sup.2, P(═O)(R.sup.2), SO, SO.sub.2, NR.sup.2, O, S, or CONR.sup.2 and wherein one or more H atoms are optionally replaced by D, F, Cl, Br, I, CN, or NO.sub.2, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.2, or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.2, or a combination of these systems, and wherein two or more adjacent substituents R.sup.2 optionally define a mono- or polycyclic, aliphatic or aromatic ring system with one another; Ar.sup.1 is on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.2 and wherein two radicals Ar.sup.1 which are bonded to the same nitrogen, phosphorus or boron atom is also optionally linked to one another by a single bond or a bridge selected from the group consisting of B(R.sup.2), C(R.sup.2).sub.2, Si(R.sup.2).sub.2, C═O, C═NR.sup.2, C═C(R.sup.2).sub.2, O, S, S═O, SO.sub.2, N(R.sup.2), P(R.sup.2), and P(═O)R.sup.2; R.sup.2 is on each occurrence, identically or differently, H, D, or an aliphatic, aromatic, and/or heteroaromatic hydrocarbon radical having 1 to 20 C atoms, wherein one or more H atoms are optionally replaced by D or F, and wherein two or more adjacent substituents R.sup.2 optionally define a mono- or polycyclic, aliphatic or aromatic ring system with one another.

6. The composition of claim 3, wherein the additional functional material is an n-dopant.

7. A formulation comprising at least one composition of claim 1 and at least one solvent.

8. A formulation comprising at least one composition of claim 3 and at least one solvent.

9. A device comprising at least one composition of claim 1.

10. A device comprising at least one composition of claim 3.

11. The device of claim 9, wherein the device is an electronic device.

12. The device of claim 10, wherein the device is an electronic device.

13. The device of claim 11, wherein the device is an electronic device selected from the group consisting of organic electroluminescent devices, organic integrated circuits, organic field-effect transistors, organic thin-film transistors, organic solar cells, organic optical detectors, organic photoreceptors, and organic field-quench devices.

14. The device of claim 12, wherein the device is an electronic device selected from the group consisting of organic electroluminescent devices, organic integrated circuits, organic field-effect transistors, organic thin-film transistors, organic solar cells, organic optical detectors, organic photoreceptors, and organic field-quench devices.

15. The device of claim 13, wherein it is an organic electroluminescent device selected from the group consisting of organic light-emitting diodes, organic light-emitting transistors, organic light-emitting electrochemical cells, and organic laser diodes.

16. The device of claim 14, wherein it is an organic electroluminescent device selected from the group consisting of organic light-emitting diodes, organic light-emitting transistors, organic light-emitting electrochemical cells, and organic laser diodes.

17. The device of claim 9, wherein the device comprises the at least one composition in an electron-conducting layer.

18. The device of claim 10, wherein the device comprises the at least one composition in an electron-conducting layer.

19. The device of claim 9, wherein the device comprises the at least one composition in an electron-injection layer or in an electron-transport layer.

20. The device of claim 10, wherein the device comprises the at least one composition in an electron-injection layer or in an electron-transport layer.

21. A process for preparing the composition of claim 1 comprising (1) preparing a ligand without metal and (2) reacting the ligand with a metal salt.

Description

EXAMPLES

Example 1

Synthesis of 2-tert-butyl-8-hydroxyquinoline

(1) 60 g of 8-hydroxyquinoline (0.41 mol) are dissolved in 200 ml of THF. The solution is cooled to −70° C., 720 ml of 1.7 M (3 eq.) tert-butyllithium are added dropwise. The yellow suspension is stirred at −70° C. for one hour and then slowly warmed to room temperature. 71 g (0.8 mol) of tert-butyl hydroperoxide are then added to this solution, and the mixture is stirred overnight. The solution is extended with 500 ml of toluene and washed once with 1 N HCl and three times with water. The solvent is removed in vacuo, and the residue is chromatographed on silica gel (heptane:ethyl acetate 10:1). The material is recrystallised once from toluene/heptane, giving 41.2 g (0.20 mol, 50%) of 2-tert-butyl-8-hydroxyquinoline as a colourless solid.

Example 2

Synthesis of lithium 2-tert-butyl-8-hydroxyquinoline (E2)

(2) 37 g (184 mmol) of 2-tert-butyl-8-hydroxyquinoline from Example 1 are dissolved in 250 ml of acetonitrile. 108 ml of 2.5 M n-BuLi in hexane (270 mmol, 1.5 eq.) are added dropwise at 0° C. After stirring overnight, the solid formed is filtered off, washed with dry acetonitrile and dried, giving 36 g (174 mmol, 95%) of lithium 2-tert-butyl-8-hydroxyquinolinate as a grey solid. The product is sublimed twice in a high vacuum (350° C./1×10.sup.−5 mbar), giving 26 g (72%) of sublimed product.

(3) Further compounds of the formula (1) according to the invention are prepared analogously.

Example 3

Synthesis of lithium 2-(2,5-dimethylphenyl)-8-hydroxyquinoline (E3)

(4) The synthesis is carried out analogously to the method disclosed in J. Am. Chem. Soc., 2010, 132, 13194.

(5) 36 g of 8-hydroxyquinoline (0.25 mol) are dissolved in 125 ml of dichloromethane, and 19 ml (0.25 mol) of trifluoroacetic acid are added. 54 g (0.37 mol) of 2,5-dimethylphenylboronic acid (Frontier Scientific) and 8.5 g (0.05 mol) of silver nitrate are then added. A solution of 100 g (0.38 mol) of potassium peroxodisulfate in 1000 ml of water is added with ice-cooling, and the mixture is warmed to room temperature. The yellow suspension is stirred for 24 hours and extended with 1 l of dichloromethane, the phases are separated, and the organic phase is washed twice with sodium hydrogencarbonate solution. The solvent is removed in vacuo, and the residue is chromatographed on silica gel (heptane:ethyl acetate 10:1). The material is recrystailised once from toluene/acetonitrile, giving 18.2 g (73 mmol, 29%) of 2-(2,5-dimethylphenyl)-8-hydroxyquinoline as a colourless solid.

(6) 10 g of the product are converted analogously to Example 2 into 7.1 g of lithium 2-(2,5-dimethylphenyl)-8-hydroxyquinoline, which is sublimed at 330° C.

Example 4

Synthesis of lithium 2-(2,6-dimethylphenyl)-8-hydroxyquinoline (E4)

(7) Analogously to Example 3, 2,6-dimethylphenylboronic acid (Frontier Scientific) is converted into lithium 2-(2,6-dimethylphenyl)-8-hydroxyquinoline and sublimed at 325° C.

Example 5

Synthesis of lithium 4-(2,6-dimethylphenyl)-8-hydroxyquinoline (E5)

(8) 10 g (44 mmol) of 4-bromo-8-hydroxyquinoline (Monatshefte für Chemie (1991), 122(11), 935-41) are dissolved in 100 ml of toluene. 100 ml of water, 7.3 g (50 mmol) of 2,6-dimethylphenylboronic acid, 20.2 g (88 mmol) of potassium phosphate hydrate, 200 mg of palladium acetate and 750 mg of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (═S—PHOS) are added. After heating under reflux for 12 hours, the mixture is cooled, the phases are separated and evaporated, and the solid which remains is chromatographed on silica gel (heptane:ethyl acetate 10:1). The material is recrystallised once from toluene/acetonitrile, giving 8.0 g (32 mmol) of 4-(2,6-dimethylphenyl)-8-hydroxyquinoline as a colourless solid. Analogously to Example 2, the material is converted into lithium 4-(2,6-dimethylphenyl)-8-hydroxyquinoline and sublimed at 340° C.

Comparative Example 1

Synthesis of lithium 8-hydroxyquinoline (V1)

(9) Commercial lithium 8-hydroxyquinoline (Green Fine Chemicals) is sublimed twice at 350° C.

Comparative Example 2

Synthesis of lithium 4-(phenyl)-8-hydroxyquinoline (V2)

(10) Analogously to Example 6, lithium 4-(phenyl)-8-hydroxyquinoline is prepared using phenylboronic acid and sublimed at 380° C. Decomposition is observed during the latter.

Comparative Example 3

Synthesis of lithium 2-(phenyl)-8-hydroxyquinoline (V3)

(11) Analogously to Example 3, lithium 2-(phenyl)-8-hydroxyquinoline is prepared using phenylboronic acid and sublimed at 370° C. Decomposition is observed during the latter.

Example 6

Mutagenicity Investigations

(12) Compounds V1 and E2 are subjected to a standardised AMES test (bacteria: Salmonella typhimurium; strains TA98, TA100 and TA102). This is referenced by means of DARN (daunomycin), NaN.sub.3 (sodium azide), 2-AA (2-aminoanthracene), B(a)p (benzo[a]pyrene) and CUM (cumene hydroperoxide). The test is carried out by the person skilled in the art employing standard methods which are well known in the prior art. The solvent used is DMSO (dimethyl sulfoxide).

(13) The test is carried out both without and also with metabolic activation using an S9 mix.

(14) No mutagenic effect is observed here for the compound from Example 2 and for further compounds according to the invention.

(15) In contrast to the compounds according to the invention, the reference compound, Liq, exhibits significant mutagenicity in all three bacteria strains in the presence of metabolic activation.

(16) The following overview summarises the results of the test for the comparative compound, Liq (V1).

(17) TABLE-US-00001 Conc. Metabol. [μg/ Revertants/plate (mean ± SD) act. Compound plate] TA98 TA100 TA102 no DMSO 21 ± 3 100 ± 6  311 ± 24 no Liq 5 23 ± 2 96 ± 3 344 ± 33 no 15.8 20 ± 4 99 ± 2 270 ± 30 no 50 22 ± 1 98 ± 4 257 ± 59 no DAUN 1 175 ± 11 no NaN.sub.3 2 1090 ± 35  no CUM 200 1481 ± 267 yes DMSO 31 ± 6 111 ± 11 390 ± 28 yes Liq 5  31 ± 11 146 ± 2  559 ± 8  yes 15.8 40 ± 2 261 ± 19 697 ± 8  yes 50 87 ± 1  599 ± 115 1469 ± 27  yes 158 100 ± 4  788 ± 75  911 ± 269 yes 2-AA 2 201 ± 58 384 ± 9  yes B(a)p 10 2266 ± 18  Metabol. act.—Metabolic activation using S9 mix; Conc.—Concentration; SD—Standard deviation

(18) The following table summarises the results for the compound according to the invention, E2.

(19) TABLE-US-00002 Metabol. Revertants/plate (mean ± SD) act. Compound Conc. [μg/plate] TA98 TA100 TA102 no DMSO  18 ± 3  128 ± 21  216 ± 18 no E2 5  23 ± 11  142 ± 25  224 ± 6 no 15.8  29 ± 3  133 ± 8  217 ± 41 no 50  18 ± 6  104 ± 12  237 ± 11 no 158  20 ± 6.sup.S  103 ± 1.sup.S  180 ± 11.sup.S no 500  14 ± 8.sup.SB  62 ± 17.sup.SB  124 ± 1.sup.SB no 1580  10 ± 4.sup.SB  41 ± 2.sup.SBT  51 ± 18.sup.SB no 5000  17 ± 6.sup.SE   7 ± 3.sup.SET  25 ± 1.sup.SE no DAUN 1  412 ± 80 no NaN.sub.3 2  743 ± 52 no CUM 200  912 ± 59 yes DMSO  30 ± 3  155 ± 11  252 ± 15 yes E2 5  24 ± 6  199 ± 4  302 ± 18 yes 15.8  30 ± 2  132 ± 11  255 ± 8 yes 50  33 ± 4  143 ± 8  245 ± 22 yes 158  30 ± 3.sup.S  147 ± 8.sup.S  142 ± 22.sup.S yes 500  25 ± 7.sup.SB  108 ± 1.sup.SB  89 ± 11.sup.SB yes 1580  18 ± 5.sup.SB  57 ± 16.sup.SBT  62 ± 3.sup.SB yes 5000  13 ± 1.sup.SE   4 ± 3.sup.SET  37 ± 1.sup.SE yes 2-AA 2 1376 ± 44 1365 ± 18 yes B(a)p 10 2751 ± 280 .sup.SPlate as suspension; .sup.BFailed at the beginning of the experiment; .sup.EFailed by the end of the experiment; .sup.TToxicity = reduced bacterial background lawn

Example 7

Characterisation of the Vapour-Deposition Behaviour

(20) The vapour-deposition behaviour is investigated by means of the “effusion method” (J- Pestic. Sci. 1982, 13, 161-168). The results are summarised in FIG. 1. Compounds E2-E5 according to the invention have significantly better evaporation than comparative compounds V1-V3.

Example 8

Production and Characterisation of the OLEDs

(21) OLEDs according to the invention and OLEDs in accordance with the prior art are produced by a general process in accordance with WO 2004/058911, which is adapted to the circumstances described here (layer-thickness variation, materials).

(22) The data of various OLEDs are presented in the following inventive example E1 and in the reference example V1. The substrates used are glass plates coated with structured ITO (indium tin oxide) in a thickness of 50 nm. The OLEDs have in principle the following layer structure: substrate/p-doped hole-transport layer A′ (HIL1)/hole-transport layer A (HTL)/hole-transport layer C (EBL)/emission layer (EML)/electron-transport layer (ETL)/electron-injection layer (EIL) and finally a cathode. The cathode is formed by an aluminium layer with a thickness of 100 nm. The materials required for the production of the OLEDs are shown in Table 1, the structure of the various electronic devices produced is shown in Table 2.

(23) All materials are applied by thermal vapour deposition in a vacuum chamber. The emission layer here always consists of at least one matrix material (host material) and an emitting dopant (emitter), which is admixed with the matrix material or matrix materials in a certain proportion by volume by co-evaporation. An expression such as H1:SEB (95%:5%) here means that material H1 is present in the layer in a proportion by volume of 95% and SEB is present in the layer in a proportion of 5%. Analogously, the electron-transport layer or the hole-injection layers may also consist of a mixture of two materials.

(24) The OLEDs are characterised by standard methods. For this purpose, the electroluminescence spectra, the current efficiency (measured in cd/A), the power efficiency (measured in lm/W) and the external quantum efficiency (EQE, measured in percent) as a function of the luminous density, calculated from current/voltage/luminous density characteristic lines (IUL characteristic lines) assuming Lambert emission characteristics, and the lifetime are determined. The electroluminescence spectra are determined at a luminous density of 1000 cd/m.sup.2, and the CIE 1931 x and y colour coordinates are calculated therefrom. The term EQE @ 10 mA/cm.sup.2 denotes the external quantum efficiency at a current density of 10 mA/cm.sup.2. LT80 @ 60 mA/cm.sup.2 is the lifetime by which the OLED has dropped to 80% of the initial intensity at a constant current of 60 mA/cm.sup.2.

(25) TABLE-US-00003 TABLE 1 Structures of the materials used 0

(26) TABLE-US-00004 TABLE 2 HIL1 HTL EBL EML ETL EIL Ex. Thickness/nm Thickness/nm Thickness/nm Thickness/nm Thickness/nm Thickness/nm V1 HIM1:F4TCNQ(5%) HIM1 EBM H1:SEB(5%) ETM(50%):LIQ(50%) LIQ 10 nm 190 nm 10 nm 20 nm 30 nm 1 nm E1 HIM1:F4TCNQ(5%) HIM1 EBM H1:SEB(5%) ETM(50%):EIM(50%) EIM 10 nm 190 nm 10 nm 20 nm 30 nm 2 nm E2 HIM1:F4TCNQ(5%) HIM1 EBM H1:SEB(5%) ETM EIM 10 nm 190 nm 10 nm 20 nm 30 nm 3 nm

(27) Sample E2 according to the invention requires approximately the same voltage of 37 V at 10 mA/cm.sup.2 as reference sample V1 with 3.8 V. Sample E1 according to the invention requires a slightly higher voltage of 4.3 V than the reference sample. Sample E2 also has a comparable efficiency of 8.9% EQE at 10 mA as the reference sample with 8.9% EQE, while sample E1 has a somewhat lower efficiency of 8.2% EQE. Sample E1 has a somewhat better lifetime LT80 of 215 h at 60 mA/cm.sup.2 than reference sample V1. Sample E2 has a somewhat shorter lifetime of 125 h. Even though all characteristic data for the LiQ samples are not identical, it can be shown that very good lifetimes and high efficiencies can be achieved with the novel LiQ derivative.

(28) It should be noted here that the OLEDs used here do not represent optimised devices, and it is possible for the person skilled in the art, without inventive step, to increase the efficiency of the OLEDs by suitable measures familiar to him. Such an increase in the efficiency can be observed, for example, if compositions according to the invention are employed instead of the individual compounds in the corresponding layers.