Materials for electronic devices

Abstract

The present invention relates to a compound, comprising a pyrene skeleton and arylamino groups, according to formula (I). The compound is suitable for use as a functional material in electronic devices. ##STR00001##

Claims

1. A compound of formulae (I-1), (I-2), or (I-3): ##STR00191## the pyrene groups of which are optionally substituted by a radical R.sup.1 at each free position; Ar.sup.1 is on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 6 to 30 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.3, and wherein groups Ar.sup.1 are optionally linked via groups X; X is on each occurrence, identically or differently, a single bond, or a divalent group selected from an aryl or heteroaryl group having 6 to 20 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.2, or BR.sup.2, C(R.sup.2).sub.2, R.sup.2CCR.sup.2, C(O), Si(R.sup.2).sub.2, NR.sup.2, PR.sup.2, P(O)R.sup.2, O, S, S(O), S(O).sub.2, or, identically or differently, any combination of 2, 3, 4 or 5 of these divalent groups; R.sup.1 is on each occurrence, identically or differently, H, D, F, C(O)R.sup.4, CN, Si(R.sup.4).sub.3, N(Ar.sup.1).sub.2, N(R.sup.4).sub.2, P(O)(R.sup.4).sub.2, O Ar.sup.1, S(O)R.sup.4, S(O).sub.2R.sup.4, a straight-chain alkyl or alkoxy group having 1 to 20 C atoms, a branched or cyclic alkyl or alkoxy group having 3 to 20 C atoms, or an alkenyl or alkynyl group having 2 to 20 C atoms, wherein these groups are optionally substituted by one or more radicals R.sup.4 and wherein one or more CH2 groups in these groups are optionally replaced by R.sup.4CCR.sup.4, CC, Si(R.sup.4).sub.2, CO, CNR.sup.4, C(O)O, C(O)NR.sup.4, NR.sup.4, P(O)(R.sup.4), O, S, SO, or SO.sub.2, or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.4, and wherein two or more radicals R.sup.1 are optionally linked to one another so as to define a ring; R.sup.2 is on each occurrence, identically or differently, H, D, F, C(O)R.sup.4, CN, Si(R.sup.4).sub.3, n N(R.sup.4).sub.2, P(O)(R.sup.4).sub.2, S(O)R.sup.4, S(O).sub.2R.sup.4, a straight-chain alkyl or alkoxy group having 1 to 20 C atoms, a branched or cyclic alkyl or alkoxy group having 3 to 20 C atoms, or an alkenyl or alkynyl group having 2 to 20 C atoms, wherein these groups are optionally substituted by one or more radicals R.sup.4 and wherein one or more CH.sub.2 groups in these groups are optionally replaced by R.sup.4CCR.sup.4, CC, Si(R.sup.4).sub.2, CO, CNR.sup.4, C(O)O, C(O)NR.sup.4, NR.sup.4, P(O)(R.sup.4), O, S, SO, or SO.sub.2, or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.4, and wherein two or more radicals R.sub.2 are optionally linked to one another so as to define a ring; R.sup.3 is on each occurrence, identically or differently, H, D, F, C(O)R.sup.4, CN, Si(R.sup.4).sub.3, N(R.sup.4).sub.2, P(O)(R.sup.4).sub.2, S(O)R.sup.4, S(O).sub.2R.sup.4, a straight-chain alkyl or alkoxy group having 1 to 20 C atoms, a branched or cyclic alkyl or alkoxy group having 3 to 20 C atoms, or an alkenyl or alkynyl group having 2 to 20 C atoms, where these groups are optionally substituted by one or more radicals R.sup.4 and wherein one or more CH2 groups in these groups are optionally replaced by R.sup.4CCR.sup.4, CC, Si(R.sup.4).sub.2, CO, CNR.sup.4, C(O)O, C(O)NR.sup.4, NR.sup.4, P(O)(R.sup.4), O, S, SO, or SO.sub.2, or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.4, and wherein two or more radicals R.sup.3 are optionally linked to one another so as to define a ring; R.sup.4 is on each occurrence, identically or differently, H, D, F or an aliphatic, aromatic or heteroaromatic organic 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 radicals R.sup.4 are optionally linked to one another so as to define a ring.

2. The compound of claim 1, wherein X is on each occurrence, identically or differently, a divalent group selected from the group consisting of C(R.sup.2).sub.2, NR.sup.2, O, and S.

3. The compound of claim 1, wherein X is on each occurrence, identically or differently, a divalent group selected from the group consisting of C(R.sup.2).sub.2 and NR.sup.2.

4. The compound of claim 1, wherein Ar.sup.1 is on each occurrence, identically or differently, an aromatic ring system having 6 to 12 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.3.

5. The compound of claim 1, wherein Ar.sup.1 is phenyl, which is optionally substituted by one or more radicals R.sup.3.

6. The compound of claim 4, wherein Ar.sup.1 is a phenyl group, which is optionally substituted by one or more radicals R.sup.3, and wherein the bond to the group X and to the nitrogen atom on the phenyl group are in the meta position relative to one another.

7. The compound of claim 1, wherein the pyrene group is substituted by at least one radical R.sup.1 which is not H.

8. The compound of claim 1, wherein the pyrene group is substituted by at least one radical R.sup.1 which is selected from a straight-chain alkyl group having 1 to 8 C atoms or a branched or cyclic alkyl group having 3 to 8 C atoms, where the alkyl groups are optionally substituted by one or more radicals R.sup.4, or from an aryl or heteroaryl group having 6 to 14 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.4.

9. The compound of claim 1, wherein radicals R.sub.2 on a group X which represent C(R.sup.2).sub.2 or Si(R.sup.2).sub.2 are selected from a straight-chain alkyl group having 1 to 8 C atoms or a branched or cyclic alkyl group having 3 to 8 C atoms, where the alkyl groups are optionally substituted by one or more radicals R.sup.4, or from an aryl or heteroaryl group having 6 to 14 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.4.

10. An oligomer, polymer, or dendrimer comprising one or more compounds of claim 1, wherein the bond(s) to the polymer, oligomer, or dendrimer may be located at any positions substituted by R.sup.1, R.sup.2, or R.sup.3 of formulae (I-1), (I-2), or (I-3).

11. A formulation comprising at least one compound of claim 1 and at least one solvent.

12. An electronic device comprising at least one compound of claim 1, wherein the electronic device is selected from the group consisting of 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, organic light-emitting electrochemical cells, organic laser diodes, and organic electroluminescent devices.

13. The electronic device of claim 12, wherein the electronic device is an organic electroluminescent device and wherein the compound of formulae (I-1), (I-2), or (I-3) is present as an emitting compound in an emitting layer.

14. A process for preparing a compound of claim 1, comprising at least one transition metal-catalysed coupling reaction.

Description

WORKING EXAMPLES

(1) A) Synthesis Examples

(2) Aniline, 1,3-dibromobenzene, 1,2-dibromobenzene, phenol, N,N-dimethylcarbamoyl chloride, 1-bromo-3-iodobenzene, 2-bromobiphenyl, 1-bromobenzene, 2-bromo-1,3-dimethylbenzene, 1-bromo-2-fluorobenzene, o-tolylamine, 4-bromodibenzofuran, 2,4-dimethylphenylamine and 2-fluorophenylamine are commercially available. The synthesis of 1,3-dibromo-7-tert-butylpyrene is described in Adv. Mat, 2010, 22, 990-993.

(3) Variant I:

(4) ##STR00148##
Compound Int-a-1

(5) ##STR00149##

(6) 1,3-Dibromo-7-tert-butylpyrene (20.0 g, 48.1 mmol) and aniline (15.7 g, 168.2 mmol) are dissolved in 300 ml of toluene. Sodium tert-butoxide (13.9 g, 144 mmol) is then added. The solution is degassed and saturated with argon. 1,1-Bis(diphenylphosphino)ferrocene (2.1 g, 3.85 mmol) and palladium(II) acetate (431 mg, 1.92 mmol) are subsequently added. The reaction mixture is heated under reflux under protective-gas atmosphere for 4 h. The mixture is filtered through silica gel and AlOx. After filtration of the crude product, the residue which remains is recrystallised from a heptane/toluene mixture, giving 21.2 g (79% of theory) of the product as yellow solid.

(7) The following compounds are prepared analogously:

(8) TABLE-US-00003 Compound Pyrene Arylamine Product Int-a-2 0 Int-a-3 Int-a-4 Compound Yield Int-a-2 91% Int-a-3 32% Int-a-4 41%
Synthesis of the Bridging Groups Int-b-1 to Int-b-3

(9) ##STR00159##

Bis-(3-bromophenyl)methanone

(10) 1,3-Dibromobenzene (59.0 g, 250 mmol) is dissolved in 1.1 l of diethyl ether and cooled to 65 C. 100 ml of n-BuLi solution (2.5 M in n-hexane) is slowly added dropwise, and the mixture is stirred for a further 1 h. N,N-Dimethylcarbamoyl chloride is added in one portion with vigorous stirring.

(11) The mixture is stirred at 65 C. for 1 h and then warmed slowly. A mixture of 250 ml of water and 25 ml of acetic acid is subsequently slowly added dropwise. The product precipitates out as white solid. The solid is filtered off with suction and rinsed with water and ethanol. The yield is 42.2 g (76% of theory) as white solid.

1-Bromo-2-phenoxybenzene

(12) 1,2-Dibromobenzene (451.1 g, 1.9 mol), phenol (150.0 g, 1.50 mol), potassium carbonate (132.2 g, 956 mmol) and copper(I) oxide (273.7 g, 1.9 mol) are mixed, and glass beads are added. The reaction mixture is stirred at an internal temperature of 180 C. overnight. The batch is cooled, and then diluted with 300 ml of DCM. The batch solution is filtered through a Bchner funnel, and then through Celite. The filtrate is evaporated in a rotary evaporator. The oil is distilled under a high vacuum (1.5 mbar, head temperature 135 C.). 168.1 g of white solid are isolated (45% of theory).

9,9-Bis-(3-bromophenyl)-9H-xanthene (Int-b-1)

(13) Magnesium (3.17 g, 120.6 mmol) is initially introduced in a flask with one crystal of iodine. 1-Bromo-2-phenoxybenzene (23.2 g, 93.2 mmol), 190 ml of anhydrous THF, 26 ml of 1,2-dimethoxyethane and 0.78 ml of 1,2-dichloroethane are initially introduced in a dropping funnel. The starting-material mixture is slowly added dropwise. The reaction is stirred at 70 C. for a further 3 h and then cooled. Bis(3-bromophenyl)methanone (32 g, 93.2 mmol) is dissolved in 200 ml of THF and slowly added dropwise. The reaction is stirred under reflux for 4 h. The batch is subsequently filtered, and the THF is removed in a rotary evaporator. 400 ml of acetic acid and 75 ml of concentrated hydrochloric acid are added, and the mixture is stirred at 75 C. for 4 h, before 200 ml of water are added. The pale solid is filtered off with suction and washed with methanol. The solid is stirred in boiling ethyl acetate for 1 h, filtered and washed with ethanol. The yield is 28.2 g (62% of theory) as white solid.

9,9-Bis-(3-bromophenyl)-9H-fluorene (Int-b-2)

(14) Magnesium (6.73 g, 255.8 mmol) is initially introduced in a flask with one crystal of iodine. 2-Bromobiphenyl (64.4 g, 276.3 mmol), 400 ml of anhydrous THF, 500 ml of anhydrous toluene, 45 ml of 1,2-dimethoxyethane and 2.65 ml of 1,2-dichloroethane are introduced into a dropping funnel. The starting-material mixture is slowly added dropwise. The reaction is stirred under reflux for a further 1 h, and subsequently cooled. Bis-(3-bromophenyl)methanone (61.4 g, 180.6 mmol) is dissolved in 600 ml of THF and slowly added dropwise. The reaction is stirred under reflux for 5 h. The batch is filtered, and the THF is evaporated in a rotary evaporator. 500 ml of glacial acetic acid, 200 ml of acetic acid and 10 ml of HBr are added, and the mixture is stirred under reflux for 64 h. The pale solid is filtered off with suction and washed with ethyl acetate and ethanol. The yield is 79.8 g (92% of theory) as white solid.

Bis-(3-bromophenyl)phenylamine (Int-b-3)

(15) 1-Bromo-3-iodobenzene (200.5 g, 708.7 mmol), aniline (30.0 g, 322 mmol), copper(I) iodide (4.92 g, 25.8 mmol), potassium hydroxide (145.8 g, 2.58 mol) and 1,10-phenanthroline (4.67 g, 25.8 mmol) are suspended in 1l of o-xylene. The solution is degassed and saturated with argon. The reaction mixture is stirred under reflux overnight. The mixture is filtered through silica gel and AlOx with toluene and subsequently evaporated in a rotary evaporator. The pale-brown solid is filtered off with suction. The solid is then purified by column chromatography (heptane). The product is stirred under reflux in heptane for 3 h and then filtered. The yield is 58.6 g (45% of theory) as white solid.

7-tert-Butyl-N,N-diphenylpyrene-1,3-diamine, Bridged to 9,9-bis-(3-bromophenyl)-9H-xanthene (1)

(16) ##STR00160##

(17) Sodium tert-butoxide (16.6 g, 173 mmol) is suspended in 500 ml of toluene. The solution is degassed and saturated with argon. 7-tert-Butyl-N,N-diphenylpyrene-1,3-diamine (19.0 g, 43.1 mmol) and 9,9-bis(3-bromophenyl)-9H-xanthene (21.2 g, 43.1 mmol) are dissolved in 1.8 l of THF, saturated with argon and introduced into a dropping funnel. Tri-tert-butylphosphine (1 M solution in toluene, 15.5 ml, 15.5 mmol) and palladium(II) acetate (2.32 g, 10.4 mmol) are then added to the base/toluene solution, and the mixture is heated under reflux. The starting-material mixture is subsequently added dropwise. The reaction is stirred for a further 2 h. The batch is filtered twice through silica gel and AlOx and evaporated in a rotary evaporator. The solid is extracted with toluene in a Soxhlet extractor and recrystallised from toluene. The yield is 1.9 g (6% of theory) as yellow solid.

(18) The following compounds are prepared analogously:

(19) TABLE-US-00004 Example compound Starting material Product Yield 2 Int-a-2 7% 3 Int-a-3 3% 4 Int-a-1 29% 5 Int-a-4 3% 6 Int-a-1 0 24%
Variant II:

Synthesis of N,N-bisbiphenyl-2-yl-7-tert-butylpyrene-1,3-diamine Bridged to triphenylamine (7)

(20) ##STR00172##

tert-Butyl (3-tert-butoxycarbonylamino-7-tert-butylpyren-1-yl)carbamate (Int-c-1)

(21) 1,3-Dibromo-7-tert-butylpyrene (5 g, 12 mmol), tert-butyl carbamate (3.66 g, 31.2 mmol) and caesium carbonate (12.5 g, 38.5 mmol) are suspended in 100 ml of anhydrous dioxane. The solution is degassed and saturated with argon. 9,9-Dimethyl-4,5-bis(diphenylphosphino)xanthene (556 mg, 0.96 mmol) and palladium(II) acetate (162 mg, 0.72 mmol) are added. The reaction is stirred under reflux overnight. The reaction mixture is filtered and extracted with heptane and then toluene in a Soxhlet extractor. The product is obtained as brown solid: 2.6 g (46% of theory).

7-tert-Butylpyrene-1,3-diamine (Int-c-2)

(22) tert-Butyl (3-tert-butoxycarbonylamino-7-tert-butylpyren-1-yl)carbamate (5.9 g, 12 mmol) is dissolved in 50 ml of DCM. Trifluoroacetic acid (11 g, 97 mmol) is added. The batch is stirred under reflux for 2 h and subsequently evaporated. The solid is dissolved in toluene and filtered through AlOx. The product is eluted over a silica-gel column with heptane/ethyl acetate 1:1. The yield is 615 mg (17.7% of theory) as black solid.

7-tert-Butylpyrene-1,3-diamine, Bridged to triphenylamine (Int-c-3)

(23) Sodium tert-butoxide (615 mg, 6 mmol) is suspended in 60 ml of dioxane. The solution is degassed and saturated with argon. 7-tert-Butylpyrene-1,3-diamine (615 mg, 2.13 mmol) and bis(3-bromophenyl)phenylamine (860 mg, 2.13 mmol) are dissolved in 100 ml of dioxane, saturated with argon and initially introduced in a dropping funnel. S-Phos (52.6 mg, 0.128 mmol) and palladium(II) acetate (52.3 mg, 0.064 mmol) are then added to the base/dioxane solution, and the reaction mixture is heated to reflux. The starting-material mixture is added dropwise. The reaction is stirred for a further 2 h. The batch is filtered twice through silica gel and AlOx and evaporated in a rotary evaporator. The yield is 883 mg (78.2% of theory) as black oil.

N,N-Bisbiphenyl-2-yl-7-tert-butylpyrene-1,3-diamine, Bridged to triphenylamine (7)

(24) ##STR00173##

(25) The starting material Int-c-3 (318 mg, 0.600 mmol), 2-bromobiphenyl (490 mg, 2.1 mmol) and sodium tert-butoxide (173 mg, 1.8 mmol) are suspended in 30 ml of toluene. The solution is degassed and saturated with argon. Tri-tert-butylphosphine (1 M solution in toluene, 0.048 ml, 0.048 mmol) and palladium(II) acetate (11.6 mg, 0.024 mmol) are then added to the reaction mixture, which is then heated under reflux. The batch is filtered through silica gel and AlOx. The solid is eluted over a silica-gel column with heptane/ethyl acetate 5:1. The yield is 60 mg (12% of theory) as yellow solid.

(26) The following compounds are prepared analogously:

(27) TABLE-US-00005 Example Starting compound Starting material 1 material 2 8 9 10 Example compound Product Yield 8 0 16% 9 21% 10 4%
B) Measurement of the Temperature Stability

(28) The behaviour of compound 4 according to the invention at high temperatures is investigated. In order to establish how high the temperature stability is, TGA measurements under protective gas of compound 4 and furthermore, for comparison, of the compound from the prior art SEBV1 are carried out (for the structures of the compounds cf. synthesis examples and Table 1 below).

(29) Both samples are measured using a TGA Q 5000 instrument from TA Instruments. Both samples are heated in nitrogen atmosphere between room temperature and 600 C. at a heating rate of 20 C. per minute.

(30) For compound 4, the temperature T.sub.x at which the mass has decreased by 5% is measured as 451 C.

(31) For the comparative compound SEBV1, a temperature T.sub.x of 401 C. is measured under the same conditions.

(32) The temperature stability is thus significantly better for compound 4 according to the invention than for the reference compound SEBV1.

(33) C) Photoluminescence Measurements

(34) Photoluminescence spectra of compound 3 according to the invention and of the compound SEBV2 known from the prior art are recorded in toluene at room temperature (concentration 10.sup.5 g/mol). For the structures of the compounds cf. Table 1 below.

(35) For compound 3 according to the invention, a CIE y coordinate of 0.077 is measured, a maximum of the emission at 447 nm, and a width of the emission band at half intensity compared with the maximum value (FWHM) of 44 nm.

(36) For the comparative compound SEBV2, a CIE y coordinate of 0.090 is measured, a maximum of the emission at 450 nm, and a width of the emission band at half intensity compared with the maximum value (FWHM) of 45 nm.

(37) A significantly deeper-blue colour impression (CIE y) with slightly shorter-wave emission and slightly smaller width of the emission band is thus measured for compound 3 according to the invention, compared with the compound in accordance with the prior art SEBV2.

(38) D) Device Examples

(39) The data of various OLEDs are presented in the following examples. OLEDs according to the invention and OLEDs in accordance with the prior art are produced by a general process in accordance with WO 04/058911, which is adapted to the circumstances described here (layer-thickness variation, materials).

(40) The OLEDs have the following structure:

(41) Glass plates coated with structured ITO (indium tin oxide) in a thickness of 50 nm are coated with 20 nm of PEDOT (poly(3,4-ethylenedioxy-2,5-thiophene), applied by spin coating from water; purchased from H. C. Starck, Goslar, Germany) for improved processing. These coated glass plates form the substrates to which the OLEDs are applied. The general layer structure is the following: substrate/optional hole-injection layer (HIL)/hole-transport layer (HTL)/optional interlayer (IL)/electron-blocking layer (EBL)/emission layer (EML)/optional hole-blocking layer (HBL)/electron-transport layer (ETL)/optional electron-injection layer (EIL) and finally a cathode. The cathode is formed by an aluminium layer with a thickness of 100 nm.

(42) The precise structure of the OLEDs is revealed by the examples. The materials required for the production of the OLEDs are shown in Table 1.

(43) All materials are applied by thermal vapour deposition in a vacuum chamber. The emission layer here always consists of at least one matrix material and an emitting compound which is admixed with the matrix material or matrix materials in a certain proportion by volume by co-evaporation. An expression such as H1(95%):SEBV1(5%) here means that material SEBV1 is present in the layer in a proportion by volume of 5% and H1 is present in the layer in a proportion of 95%. Analogously, the electron-transport layer may also consist of a mixture of two materials.

(44) 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 spectrum 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 lifetime LT80 @ 60 mA is defined as the time after which the luminous density has dropped to 80% on operation with constant current of 60 mA/cm.sup.2. The values for the lifetime can be converted into a figure for other initial luminous densities with the aid of conversion formulae known to the person skilled in the art.

(45) The examples are explained in greater detail below in order to illustrate the properties and advantages of the OLEDs according to the invention. Even the improvement of a single parameter can represent a significant advance here, since different applications make different requirements with respect to individual parameters.

(46) Materials 1 and 4 according to the invention are tested as emitters in blue-emitting OLEDs. Furthermore, an OLED comprising the emitter SEBV1 known from the prior art is produced.

(47) The test structure used is the following structure: ITO/PEDOT (20 nm)/HTM1 (140 nm)/HIL1 (5 nm)/HTM2 (20 nm)/H1:x % of emitter (20 nm)/ETM1:50% of LiQ (30 nm)/Al.

(48) Compound 1 according to the invention exhibits a colour coordinate CIE x/y of 0.137/0.100, (0.135/0.105), an EQE of 5.8% (6.4%) and a lifetime LT80 of 25 h (20 h) in the above test component in the case of 3%(5%) doping at 1000 cd/m.sup.2.

(49) Compound 4 according to the invention has a colour coordinate CIE x/y of 0.133/0.118, (0.134/0.117), an EQE of 6.6% (6.8%) and a lifetime LT80 of 47 h (31 h) under the same conditions in the case of 3%(5%) doping.

(50) The reference emitter SEBV1 exhibits a colour coordinate CIE x/y of 0.137/0.102 (0.136/0.109), an EQE of 5.7% (5.8%) and a lifetime LT80 of 27 h (31 h) in the case of 3%(5%) doping at 1000 cd/m.sup.2.

(51) The materials according to the invention thus give rise to improvements over the prior art in all parameters, especially with respect to lifetime and efficiency, on use as emitters in OLEDs.

(52) TABLE-US-00006 TABLE 1 Structural formulae of the materials used for the OLEDs HIL1 HTM1 HTM2 H1 SEBV1 SEBV2 ETM1 0 LiQ