Materials for organic electroluminescence devices

Abstract

The present invention relates to novel materials which can be used in organic electronic devices, in particular electroluminescent devices, and are certain derivatives of fused aromatic systems.

Claims

1. A mixture comprising at least one compound of the Formula (I) and one or more dopants; ##STR00078## wherein Ar.sup.1 is, identically or differently on each occurrence, a fused aryl or heteroaryl group having at least 14 aromatic ring atoms optionally substituted by one or more R; X is, identically or differently on each occurrence, a group of formula (2) or (3) ##STR00079## wherein the dashed bond is a link from Ar.sup.2 or Q to Ar.sup.1; Y is, identically or differently on each occurrence, X; an Ar.sup.3 group; or an N(Ar.sup.3).sup.2 group, wherein the two Ar.sup.3 radicals are optionally bonded to one another by a single bond or via an O, S, N(R), or C(R).sub.2 group; Ar.sup.2 is, identically or differently on each occurrence, an aryl or heteroaryl group optionally substituted by one or more R and to which a group Q is bonded, with the proviso that either the group Q or an R other than H is bonded in the orthoposition to the Ar.sup.1Ar.sup.2 bond; Ar.sup.3 is, identically or differently on each occurrence, an aromatic or heteroaromatic ring system optionally substituted by one or more R; Q is, identically or differently on each occurrence, a linear, branched, or cyclic alkylene or alkylidene group which forms two bonds to Ar.sup.2 or one bond to Ar.sup.1 and one bond to Ar.sup.2 and thereby defining a further ring system; wherein Q has up to 20 C atoms optionally substituted by R.sup.1, wherein one or more non-adjacent C atoms are optionally replaced by NR.sup.1, O, S, OOOO, COO, CR.sup.1CR.sup.1, orCC, and one or more H atoms are optionally replaced by F, Cl, Br, I, or CN, wherein Q is bonded to the ortho-position of Ar.sup.2, where said ortho-position is relative to the link between Ar.sup.2 and Ar.sup.1; R is, identically or differently on each occurrence, H, F, Cl, Br, I, CN, a straight-chain alkyl or alkoxy chain having up to 40 C atoms, or a branched or cyclic alkyl or alkoxy group having 3 to 40 C atoms, wherein said straight-chain alkyl or alkoxy chain or said branched or cyclic alkyl or alkoxy group are optionally substituted by R.sup.1, wherein one or more non-adjacent C atoms are optionally replaced by NR.sup.1, O, S, OCOO, COO, CR.sup.1CR.sup.1, or CC, and wherein one or more H atoms are optionally replaced by F, Cl, Br, I, CN, or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms optionally substituted by one or more R.sup.1, or a combination of two, three or four of these systems; and wherein two or more R here optionally define a further mono- or polycyclic, aliphatic, or aromatic ring system with one another; R.sup.1is, identically or differently on each occurrence, H or a hydrocarbon radical having up to 20 C atoms, wherein said hydrocarbon radical is optionally aliphatic or aromatic or a combination of aliphatic and aromatic, and wherein one or more H atoms are optionally replaced by F; m is, on each occurrence, 0 or 1; p is, on each occurrence, 0, 1, or 2; with the proviso that the following compound is excluded as a compound of formula (1): ##STR00080##

2. The mixture of claim 1, wherein said dopants are selected from the group consisting of aromatic anthracenamines, aromatic anthracenediamines, aromatic pyrenamines, aromatic pyrene-diamines, monostyrylamines, distyrylamines, tristyrylamines, tetrastyrylamines, styrylphosphines, styryl ethers, and arylamines.

3. The mixture of claim 2, wherein Ar.sup.1 is selected from the group consisting of anthracene, acridine, phenanthrene, phenanthroline, pyrene, naphthacene, chrysene, pentacene, phenanthroline, and perylene, each of which is optionally substituted by R.

4. The mixture of claim 1, wherein Ar.sup.1 contains three, four, five, or six aromatic or heteroaromatic units, which are in each case fused to one another via one or more common edges and are optionally substituted by R.

5. The mixture of claim 1, wherein the compound of formula (1) is selected from the group consisting of structures of formula (7), (8), (9), (10), (11), and (12): ##STR00081## wherein the anthracene, phenanthrene, and pyrene units are optionally substituted by one or more R.

6. The mixture of claim 1, wherein Ar.sup.3 is, identically or differently on each occurrence, an aromatic or heteroaromatic ring system having 5 to 20 aromatic ring atoms optionally substituted by R.

7. The mixture of claim 1, wherein Ar.sup.2, is, identically or differently on each occurrence, an aryl or heteroaryl group having 5 to 16 aromatic ring atoms optionally substituted by R.

8. The mixture of claim 1, wherein Q is a linear, branched, or cyclic alkylene chain having 2 to 15 C atoms optionally substituted by R.sup.1, wherein one or more non-adjacent C atoms are optionally replaced by NR.sup.1, O, or S and one or more H atoms are optionally replaced by F or CN.

9. The mixture of claim 1, wherein Q defines a 6- , 7-, or 8-membered ring system together with Ar.sup.1 and Ar.sup.2 or defines a 3-, 4-, 5-, 6-, 7-, or 8-membered ring system together with Ar.sup.2.

10. The mixture of claim 1, wherein the structures of formula (2) are selected from the group consisting of the structures of formula (15), (16), (17), (18), (19), and (20): ##STR00082## wherein the phenyl, naphthyl, or anthryl unit are in each case optionally substituted by R and wherein the dashed bond is the link to the Ar.sup.1 unit.

11. The mixture of claim 1, wherein the structures of formula (2) are selected from the group consisting of the structures of formula (21), (22), (23), and (24): ##STR00083## wherein Z is CR.sub.2, O, S, NR, PR, P(O)R, SiR.sub.2, or CR.sub.2CR.sub.2; n is 1, 2, or 3; and the dashed bond is the link to the Ar.sup.1 unit.

12. The mixture of claim 1, wherein Q defines a ring system with Ar.sup.2.

13. The mixture of claim 1, wherein Q contains no benzylic protons or a bridgehead C atom is linked directly to Ar.sup.2.

14. The mixture of claim 1, wherein p is 0 or 1.

15. The mixture of claim 1, wherein said compounds of the formula (I) are selected from structures (1) to (98): ##STR00084## ##STR00085## ##STR00086## ##STR00087## ##STR00088## ##STR00089## ##STR00090## ##STR00091## ##STR00092## ##STR00093## ##STR00094## ##STR00095## ##STR00096## ##STR00097## ##STR00098## ##STR00099## ##STR00100## ##STR00101## ##STR00102## ##STR00103##

Description

EXAMPLES

(1) The following syntheses are carried out under a protective-gas atmosphere, unless indicated otherwise. The starting materials can be purchased from ALDRICH or ABCR (tris(dibenzylideneacetone)dipalladium(0), 2-dicyclohexylphosphino-2,6-dimethoxybiphenyl, 9,10-dibromoanthracene, 1,6-dibromopyrene, 1,3,6,8-tetrabromopyrene, inorganics, solvents). 5-Bromo-1,2,3,4-tetrahydro-1,4-methanonaphthalene is prepared by the method of Tanida et al., J. Am. Chem. Soc. 1965, 87(21), 4794, and 5-bromo-1,1,4,4-tetramethyl-1,2,3,4-tetrahydro-8-methylnaphthalene is prepared analogously to 6-bromo-1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene by the method of Garipova at al., Tetrahedron 2005, 61(20), 4755. 5-Bromo-1,2,3,4-tetrahydronaphthalene is synthesised as described in Synthetic Communications 1992, 22(8), 1095-1099. (5,6,7,8-Tetrahydro-1-naphthyl)boronic acid is synthesised as described in US 2002/019527.

Example 1

9,10-Bis(1,2,3,4-tetrahydro-1,4-methanonaphth-5-yl)anthracene

a) 1,2,3,4-Tetrahydro-1,4-methanonaphthalene-5-boronic acid

(2) ##STR00035##

(3) 100 ml (250 mmol) of n-butyllithium (2.5M in hexane) are added dropwise to a solution, cooled to 78 C., of 44.6 g (200 mmol) of 5-bromo-1,2,3,4-tetrahydro-1,4-methanonaphthalene in 500 ml of THF. The reaction mixture is stirred at 78 C. for 1 h, and a mixture of 33.5 ml (300 mmol) of trimethyl borate in 50 ml of THF is then added rapidly. After warming to 10 C., the mixture is hydrolysed using 10 ml of 2.5M hydrochloric acid, and 500 ml of methyl tert-butyl ether are then added. The organic phase is separated off, washed with water, dried over sodium sulfate and evaporated to dryness. The residue is taken up in 200 ml of n-heptane, and the colourless solid is filtered off with suction, washed with n-heptane and dried under reduced pressure. Yield: 24.1 g (128 mmol), 64.1% of theory; purity: 98% according to .sup.1H-NMR.

b) 9,10-Bis(1,2,3,4-tetrahydro-1,4-methanonaphth-5-yl)anthracene

(4) ##STR00036##

(5) 915 mg (1 mmol) of tris(dibenzylidenacetone)dipalladium(0) and 821 mg (2 mmol) of 2-dicyclohexylphosphino-2,6-dimethoxybiphenyl are added to a suspension of 16.8 g (50 mmol) of 9,10-dibromoanthracene, 21.6 g (115 mol) of 1,2,3,4-tetrahydro-1,4-methanonaphthalene-5-boronic acid and 66.9 g (315 mmol) of tripotassium phosphate in 400 ml of anhydrous toluene, and the mixture is refluxed for 16 h. After the reaction mixture has been cooled, 400 ml of water are added, and the precipitate is filtered off with suction, washed three times with 200 ml of water each time, washed three times with 200 ml of ethanol each time, dried under reduced pressure and subsequently chromatographed on silica gel (eluent heptane/toluene 8:2, v/v, column temperature 50 C.). Sublimation: p=110.sup.5 mbar, 300 C. Yield: 13.1 g (28 mmol), 56.6% of theory; purity: 99.5% according to .sup.1H-NMR (including all isomers).

Example 2

1,6-Bis(1,2,3,4-tetrahydro-1,4-methanonaphth-5-yl)pyrene

(6) ##STR00037##

(7) Preparation analogous to Example 1. Instead of 9,10-dibromoanthracene, 18.0 g (50 mmol) of 1,6-dibromopyrene are used. Purification by recrystallisation from NMP. Yield: 16.8 g (34.5 mmol), 69.0% of theory; purity: 99.9% according to .sup.1H-NMR.

Example 3

9,10-Bis(5,6,7,8-tetrahydro-1-naphthyl)anthracene

(8) ##STR00038##

(9) 688 mg (2.26 mmol) of tri-o-tolylphosphine and then 84 mg (0.37 mmol) of palladium(II) acetate are added to a vigorously stirred, degassed suspension of 12.7 g (37.7 mmol) of 9,10-dibromoanthracene, 17.2 g (97.7 mmol) of (5,6,7,8-tetrahydro-1-naphthyl)boronic acid and 26.6 g (126 mmol) of tripotassium phosphate in a mixture of 230 ml of toluene, 115 ml of dioxane and 170 ml of water, and the mixture is refluxed for 60 h. After cooling, the organic phase is separated off, washed three times with 200 ml of water and once with 200 ml of saturated, aqueous sodium chloride solution, dried over magnesium sulfate and evaporated to dryness under reduced pressure. The grey residue obtained in this way is recrystallised from dioxane. The deposited crystals are filtered off with suction, washed with 50 ml of ethanol and dried under reduced pressure; yield: 7.5 g, 45% having a purity of 99.8% according to HPLC.

(10) The following compounds are prepared analogously to Examples 1 to 3:

(11) TABLE-US-00001 Example Aryl bromide Product 4 0 5 6 7 8 9 0 10 11 12

Example 13

9,10-Bis(1,1,4,4-tetramethyl-1,2,3,4-tetrahydro-8-methylnaphth-5-yl)anthracene

a) 1,1,4,4-Tetramethyl-1,2,3,4-tetrahydro-8-methylnaphthalene-5-boronic acid

(12) ##STR00057##

(13) Preparation analogous to Example 1a. Instead of 5-bromo-1,2,3,4-tetrahydro-1,4-methanonaphthalene, 56.2 g (200 mmol) of 5-bromo-1,1,4,4-tetramethyl-1,2,3,4-tetrahydro-8-methylnaphthalene are employed. Yield: 36.5 g (148 mmol), 74.1% of theory; purity: 98% according to .sup.1H-NMR.

b) 9,10-Bis(1,1,4,4-tetramethyl-1,2,3,4-tetrahydro-8-methylnaphthalen-5-yl)anthracene

(14) ##STR00058##

(15) Preparation analogous to Example 1b. Instead of 21.6 g (115 mmol) of 1,2,3,4-tetrahydro-1,4-methanonaphthalene-5-boronic acid, 36.9 g (150 mmol) of 1,1,4,4-tetramethyl-1,2,3,4-tetrahydro-8-methylnaphthalene-5-boronic acid are used. Sublimation: p=110.sup.5 mbar, 310 C. Yield: 15.9 g (27.5 mmol), 54.9% of theory; purity: 99.9% according to .sup.1H-NMR, atropisomerically pure.

(16) The following compounds are prepared analogously to Example 13:

(17) TABLE-US-00002 Example Aryl bromide Product 14 0 15 16 17 18 19 0 20 21

Example 22

Production of Fluorescent OLEDs Comprising Host Materials H1-H6 According to the Invention for Blue-electroluminescent OLEDs

(18) OLEDs are produced by a general process as described in WO 04/058911, which is adapted in individual cases to the particular circumstances (for example layer-thickness variation in order to achieve optimum efficiency or colour).

(19) The results for various OLEDs are presented in Examples 23 to 42 below. The basic structure and the materials used (apart from the emitting layer) are identical in the examples for better comparability. OLEDs having the following structure are produced analogously to the above-mentioned general process:

(20) TABLE-US-00003 Hole-injection 20 nm PEDOT (spin-coated from water; layer (HIL) purchased from H. C. Starck, Goslar, Germany; poly(3,4-ethylenedioxy-2,5-thiophene)) Hole-transport 20 nm 2,2,7,7-tetrakis(di-para-tolylamino)- layer (HTL1) spiro-9,9-bifluorene (vapour-deposited) Hole-transport 20 nm NPB (N-naphthyl-N-phenyl-4,4-di- layer (HTL2) aminobiphenyl) Emission layer 30 nm layer of H1 to H7 as host material (EML) doped with x % (see table) of dopant E1 (vapour-deposited, synthesised as described in WO 06/000388) Electron 20 nm (vapour-deposited; AlQ.sub.3 purchased conductor (ETC) from SynTec; tris(quinolinolato)-aluminium(III)) Cathode 1 nm LiF, 150 nm Al on top.

(21) The OLEDs can also be produced without PEDOT as hole-injection layer. In this case, the HTL1 then serves as hole-injection layer. Comparable results are obtained with these OLEDs.

(22) These OLEDs are characterised by standard methods; for this purpose, the electroluminescence spectra, the efficiency (measured in cd/A) and the power efficiency (measured in Im/W) as a function of the brightness, calculated from current/voltage/brightness characteristic lines (IUL characteristic lines), are determined.

(23) The host materials used (H1 to H7) and the emitter material used (E1) are listed below. The host H7 serves as comparative material in accordance with the prior art.

(24) ##STR00075## ##STR00076##

(25) Table 1 shows the results for some OLEDs (Examples 23 to 42). As can be seen from the examples in Table 1, OLEDs comprising the host materials according to the invention (H1 to H6) in combination with emitter E1 exhibit efficient blue emission. Greater efficiency and a darker blue colour are obtained here than with di-1-naphthylanthracene in accordance with the prior art.

(26) TABLE-US-00004 TABLE 1 Max. Voltage (V) efficiency at Example EML (cd/A) 1000 cd/m.sup.2 CIE 23 H1 7.7 6.3 x = 0.16; 5% E1 y = 0.25 24 H1 6.9 6.5 x = 0.16; 3% E1 y = 0.21 25 H2 7.2 6.2 x = 0.16; 3% E1 y = 0.21 26 H2 8.1 6.1 x = 0.16; 5% E1 y = 0.25 27 H2 7.8 6.0 x = 0.16; 7% E1 y = 0.27 28 H3 7.7 6.2 x = 0.16; 3% E1 y = 0.22 29 H3 8.2 6.0 x = 0.16; 5% E1 y = 0.25 30 H3 7.5 6.3 x = 0.16; 7% E1 y = 0.26 31 H4 7.1 6.4 x = 0.16; 3% E1 y = 0.22 32 H4 8.1 6.0 x = 0.16; 5% E1 y = 0.25 33 H4 7.2 6.2 x = 0.16; 7% E1 y = 0.29 34 H5 7.5 6.2 x = 0.16; 3% E1 y = 0.22 35 H5 8.3 6.1 x = 0.16; 5% E1 y = 0.25 36 H5 7.5 6.1 x = 0.16; 7% E1 y = 0.28 37 H6 7.7 6.6 x = 0.16; 3% E1 y = 0.29 38 H6 8.5 6.5 x = 0.16; 5% E1 y = 0.32 39 H6 7.0 6.1 x = 0.16; 7% E1 y = 0.33 40 H7 6.3 6.9 x = 0.16; (comparison) 3% E1 y = 0.23 41 H7 7.8 6.1 x = 0.16; (comparison) 5% E1 y = 0.28 42 H7 6.5 6.0 x = 0.16; (comparison) 7% E1 y = 0.30

Example 43

(27) Examples of OLEDs which comprise emitters according to the invention are shown below. Emitters E2 and E3 according to the invention used are listed below:

(28) ##STR00077##

(29) Table 2 shows the results for some OLEDs (Examples 44 to 50). As can be seen from the examples in Table 2, OLEDs comprising emitter E2 or E3 according to the invention exhibit good efficiencies and good blue colour coordinates. Furthermore, emitters E2 and E3 according to the invention have greater thermal stability than emitter E1 in accordance with the prior art.

(30) TABLE-US-00005 TABLE 2 Max. Voltage (V) efficiency at Example EML (cd/A) 1000 cd/m.sup.2 CIE 44 H7 6.5 6.5 x = 0.16; 5% E2 y = 0.20 45 H7 6.6 6.4 x = 0.16; 5% E3 y = 0.18 46 H7 6.8 6.3 x = 0.16; 7% E3 y = 0.21 47 H2 6.8 6.4 x = 0.15; 5% E2 y = 0.20 48 H2 6.9 6.5 x = 0.16; 5% E3 y = 0.20 49 H5 6.7 6.4 x = 0.16; 5% E2 y = 0.21 50 H5 6.8 6.3 x = 0.16; 5% E3 y = 0.20