Compounds for electronic devices

Abstract

The present invention relates to compounds of the formula (I), ##STR00001##
to the use of compounds of the formula (I) in electronic devices, and to electronic devices containing one or more compounds of the formula (I). The invention furthermore relates to preparation processes for compounds of the formula (I) and to formulations comprising one or more compounds of the formula (I).

Claims

1. A compound of the formula (Ia) ##STR00313## wherein X.sup.1, X.sup.2 and X.sup.3 are on each occurrence a divalent group selected, identically or differently, from BR.sup.1, C(R.sup.1).sub.2, Si(R.sup.1).sub.2, CNR.sup.1, CC(R.sup.1).sub.2, NR.sup.1, O, S, SO, S(O).sub.2, PR.sup.1 or P(O)R.sup.1; Z is on each occurrence selected, identically or differently, from CR.sup.1 and N; Ar.sup.1 and Ar.sup.2 are on each occurrence, identically or differently, an aryl group having 6 to 60 aromatic ring atoms or a heteroaryl group having 5 to 60 aromatic ring atoms, wherein said aryl or heteroaryl group is optionally substituted by one or more radicals R.sup.2; R.sup.1 and R.sup.2 are on each occurrence, identically or differently, H, D, F, CN, Si(R.sup.3).sub.3, N(R.sup.3).sub.2 or a straight-chainalkyl or alkoxy group having 1 to 20 C atoms or a branched or cyclic alkyl or alkoxy group having 3 to 20 C atoms, wherein said straight-chain alkyl or alkoxy group or said branched or cyclic alkyl or alkoxy group is optionally substituted by one or more radicals R.sup.3, where one or more CH.sub.2 groups in said straight-chain alkyl or alkoxy group or the branched or cyclic alkyl or alkoxy group is optionally replaced by CC, R.sup.3CCR.sup.3, Si(R.sup.3).sub.2, CO, CNR.sup.3, NR.sup.3, O, S, COO or CONR.sup.3, or an aryl or heteroaryl group having 5 to 20 aromatic ring atoms, which may is optionally substituted by one or more radicals R.sup.3, where two or more radicals R.sup.1 or R.sup.2 may be linked to one another and may form an aliphatic or aromatic ring system; R.sup.3 is on each occurrence, identically or differently, H, D, F, CI, Br, B(OR.sup.4).sub.2, CHO, C(O)R.sup.4, CR.sup.4C(R.sup.4).sub.2, CN, COOR.sup.4, CON(R.sup.4).sub.2, Si(R.sup.4).sub.3, N(R.sup.4).sub.2, NO.sub.2, P(O)(R.sup.4).sub.2, OSO.sub.2R.sup.4, OH, S(O)R.sup.4, S(O).sub.2R.sup.4, a straight-chainalkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms, wherein said straight-chainalkyl, alkoxy or thioalkyl group or said branched or cyclic alkyl, alkoxy or thioalkyl group is optionally substituted by one or more radicals R.sup.4, where one or more CH.sub.2 groups in said straight-chainalkyl, alkoxy or thioalkyl group or said branched or cyclic alkyl, alkoxy or thioalkyl group is optionally replaced by R.sup.4CCR.sup.4, CC, Si(R.sup.4).sub.2, Ge(R.sup.4).sub.2, Sn(R.sup.4).sub.2, CO, CS, CSe, CNR.sup.4, COO, CONR.sup.4, NR.sup.4, P(O)(R.sup.4), O, S, SO or SO.sub.2 and where one or more H atoms is optionally replaced by D, F, CI, Br, I, CN or NO.sub.2, or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, said aromatic or heteroaromatic ring system is optionally substituted by one or more radicals R.sup.4, or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which is optionally substituted by one or more radicals R.sup.4 where two or more radicals R.sup.3 is optionally linked to one another and may form an aliphatic or aromatic ring system; R.sup.4 is, identically or differently on each occurrence, H, D, F or an aliphatic, aromatic and/or heteroaromatic organic radical having 1 to 20 C atoms, in which, in addition, one or more H atoms in said organic radical is optionally replaced by D or F; two or more identical or different substituents R.sup.4 here is optionally linked to one another and form an aliphatic or aromatic ring system; and with the proviso that all three groups X.sup.1, X.sup.2 and X.sup.3 do not simultaneously represent O, that all three groups X.sup.1, X.sup.2 and X.sup.3 do not simultaneously represent S, and that, if one or more of the groups X, X.sup.2 and X.sup.3 represent a group of the formula NR.sup.1, Was a constituent of the group NR.sup.1 is an aryl or heteroaryl group having 5 to 20 aromatic ring atoms, which may in each case be substituted by one or more radicals R.sup.3.

2. The compound according to claim 1, wherein X.sup.1, X.sup.2 and X.sup.3 are on each occurrence, identically or differently, selected from C(R.sup.1).sub.2, NR.sup.1, O or S and with the proviso that all three groups X.sup.1, X.sup.2 and X.sup.3 do not simultaneously represent O, that all three groups X.sup.1, X.sup.2 and X.sup.3 do not simultaneously represent S and that, if one or more of the groups X.sup.1, X.sup.2 and X.sup.3 represent a group of the formula NR.sup.1, R.sup.1 as a constituent of the group NR.sup.1 is an aryl or heteroaryl group having 5 to 20 aromatic ring atoms, which may in each case be substituted by one or more radicals R.sup.3.

3. The compound according to claim 1, wherein the groups Ar.sup.1 and Ar.sup.2 are selected on each occurrence, identically or differently, from the following groups: ##STR00314## where the groups is optionally fused to the remainder of the compound via any desired bond ZZ, where these Z cannot be equal to N, Z is otherwise as defined in claim 1, and furthermore Y is selected on each occurrence, identically or differently, from C(R.sup.2).sub.2, CO, NR.sup.2, O, S, SO or S(O).sub.2.

4. The compound according to claim 3, wherein not more than three groups Z per aromatic ring are equal to N and the remaining groups Z are equal to CR.sup.1.

5. A formulation comprising at least one compound according to claim 1 and at least one solvent.

6. An electronic device which comprises the compound according to claim 1.

7. The electronic device according to claim 6, wherein the device is an organic electroluminescent device (OLED).

8. The electronic device according to claim 6, wherein the device is an organic integrated circuit (O-IC), an organic field-effect transistor (O-FET), an organic thin-film transistor (O-TFT), an organic light-emitting transistor (O-LET), an organic solar cell (O-SC), an organic optical detector, an organic photoreceptor, an organic field-quench device (O-FQD), a light-emitting electrochemical cell (LEC), an organic laser diode (O-laser) or an organic electroluminescent device (OLED).

9. An electronic device which comprises the compound according to claim 1 is employed as a hole-transport material in a hole-transport layer or a hole-injection layer or is employed as a matrix material in an emitting layer or is employed as dopant in an emitting layer.

Description

USE EXAMPLES

(1) I. Synthesis Examples

A) 5,8-Bisbiphenyl-4-yl-13,13-dimethyl-8,13-dihydro-5H-5,8-diazaindeno[1,2-a]anthracene A

1) Synthesis of Tert-butyl 3-bromocarbazole-9-carboxylate A1

(2) ##STR00293##

(3) 147.12 g (674.1 mmol) of di-tert-butyl dicarbonate are dissolved in 1000 ml of degassed THF, and 118.5 g (481.5 mmol) of 3-bromo-9H-carbazole and 5.94 g (48.15 mmol) of DMAP are added (caution: evolution of gas!). The reaction mixture is subsequently slowly heated under reflux. The cooled reaction solution is carefully added to water and extracted with methylene chloride and dried, giving a yellow oil, which is washed by stirring with hot heptane and crystallised with ultrasound treatment, giving 116.1 g (69%) of the product as a white solid.

2) Synthesis of Tert-butyl 3-(2-methoxycarbonylphenylamino)carbazole-9-carboxylate A2

(4) ##STR00294##

(5) 63.4 g (183.12 mmol) of the bromide A1 are dissolved in 1200 ml of dry toluene with 39.0 ml (302.15 mmol) of methyl anthranilate, and 27.4 ml (27.4 mmol, 1 M in toluene) of tris-tert-butylphosphine are added via a syringe. 103.2 g (316.8 mmol) of Cs.sub.2CO.sub.3 and 3.28 g (14.7 mmol) of Pd(OAc).sub.2 are added, and the mixture is heated under reflux for about 2.5 h. When the conversion is complete, the cooled batch is filtered through silica gel and evaporated in a rotary evaporator. MeOH is added to the oil obtained, and the mixture is stirred at 50 C. for 3 min. The precipitate which deposits is washed a number of times with a little MeOH, giving 63.1 g (83%) of the product as beige crystals.

3) Synthesis of Methyl 2-(9H-carbazol-3-ylamino)benzoate A3

(6) ##STR00295##

(7) 80.5 g (193.3 mmol) of the ester A2 are dissolved in 600 ml of dichloromethane and 4.2 ml (38.5 mmol) of anisole. 15.7 ml of trifluoroacetic acid are then slowly added at room temperature, and the reaction mixture is heated to 40 C. Anisole and trifluoroacetic acid are subsequently added a number of times in portions until the conversion is complete. The cooled reaction mixture is subsequently added to ice-water and carefully, but as rapidly as possible, adjusted to pH=7-8 using 20% NaOH solution. The mixture is extracted with methylene chloride, dried, filtered and evaporated. The oily solid obtained is washed by stirring with warm heptane, giving 43.9 g (72%) of the product as a solid.

4) Synthesis of 2-[2-(9H-carbazol-3-ylamino)phenyl]propan-2-ol A4

(8) ##STR00296##

(9) 43.9 g (138.8 mmol) of the ester A3 are dissolved in dry THF and cooled to 78 C. 315.4 ml (693.8 mmol, 2.2 M in diethyl ether) of MeLi are added dropwise at this temperature. Complete conversion is observed after about 5 h at a temperature of 40 C. 240 ml of MeOH are slowly added at 30 C. (caution: evolution of gas commences), and the mixture is extracted with ethyl acetate and water. The organic phase is dried, and the yellow solid obtained is washed by stirring with warm heptane, giving 42.7 g (97%) of the product as yellow-beige crystals.

5) Synthesis of 13,13-dimethyl-8,13-dihydro-5H-5,8-diazaindeno[1,2-a]-anthracene A5

(10) ##STR00297##

(11) 42.6 g of the alcohol A4 are dissolved in 1000 ml of dichloromethane and cooled to 5 C. A mixture of 87.4 ml (1.35 mol) of methanesulfonic acid (10 eq.) and 118.8 g (1.21 mol) of polyphosphoric acid (9 eq.) is subsequently carefully added at 5 C. The reaction solution becomes pale pink in the process, and an oil deposits. The reaction is monitored via TLC (micro work-up) and subsequently carefully adjusted to pH=7-8 at low temperature using 20% NaOH. The organic phase is separated off, washed, dried and evaporated. The two isomers formed are separated by column chromatography (EA:H 9:1). The product obtained is again washed by stirring with hot heptane, giving 15 g (37%) of the product having a purity of >99.5% as a white solid.

6) Synthesis of 5,8-bisbiphenyl-4-yl-13,13-dimethyl-8,13-dihydro-5H-5,8-diazaindeno[1,2-a]anthracene A

(12) ##STR00298##

(13) 15 g (50.3 mmol) of the amine A5 are dissolved in degassed toluene, and 29.2 g (125.7 mmol) of 4-bromobiphenyl are added. 3.5 ml (3.52 mmol, 1 M in toluene) of tri-tert-butylphosphine, 0.45 g (2.01 mmol) of PdOAc.sub.2 and 14.4 g (150.8 mmol) of NaOtBu are subsequently added. The mixture is heated under reflux for about 4 h, and 4-bromobiphenyl is again added if necessary. The reaction solution is allowed to cool, and water is added, whereupon the product precipitates out as a grey precipitate. The crude product is crystallised from O-dichlorobenzene, giving 20.3 g (66.9%) of the product as a yellowish solid having a purity of 99.99%.

B) Dimethyl-5,8-dinaphthalen-1-yl-8,13-dihydro-5H-5,8-diazaindeno-[1,2-a]anthracene B

(14) ##STR00299##

(15) Tri-tert-butylphosphine (2.4 ml of a 1 M solution in toluene), sodium tert-butoxide (9.7 g, 101 mmol) and palladium acetate (0.3 g, 1.3 mmol) are added to a solution of 13,13-dimethyl-8,13-dihydro-5H-5,8-diazaindeno-[1,2-a]anthracene A5 (10.0 g, 34 mmol) and 1-bromonaphthalene (17.4 g, 84 mmol) in degassed xylene (200 ml), and the mixture is heated under reflux for 2 h. After the reaction mixture has cooled to room temperature, the precipitated solid is filtered off and extracted with heptane in a Soxhlet extractor. The crude product is subsequently recrystallised four times from toluene and purified by sublimation twice in vacuo (p=510.sup.5 mbar, T=270 C.).

(16) Yield: 6.6 g (12 mmol), 35% of theory, purity >99.9% according to HPLC, colourless solid.

(17) II. Device Examples

(18) 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).

(19) In Examples C1 to I5 below (see Tables 1 and 2), the data for various OLEDs are presented. Glass plates coated with structured ITO (indium tin oxide) in a thickness of 150 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 OLEDs basically have the following layer structure: 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) and finally a cathode. The cathode is formed by an aluminium layer with a thickness of 100 nm. The precise structure of the OLEDs is shown in Table 1. The materials required for the production of the OLEDs are shown in Table 3.

(20) 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), to which the matrix material or materials is (are) admixed by co-evaporation in a certain proportion by volume. An expression such as ST1:TEG1 (90%:10%) here means that the material ST1 is present in the layer in a proportion by volume of 90% and TEG1 is present in the layer in a proportion of 10%. Analogously, the electron-transport layer may also consist of a mixture of two materials.

(21) The OLEDs are characterised by standard methods. To this end, 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), 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 expression U1000 in Table 2 denotes the voltage required for a luminous density of 1000 cd/m.sup.2. CE1000 and PE1000 denote the current and power efficiency respectively which are achieved at 1000 cd/m.sup.2. Finally, EQE1000 is the external quantum efficiency at an operating luminous density of 1000 cd/m.sup.2. The lifetime LT is defined as the time after which the luminous density has dropped from the initial luminous density L0 to a certain proportion L1 on operation at constant current. The expression L0=4000 cd/m.sup.2 and L1=80% in Table 2 means that the lifetime indicated in column LT corresponds to the time after which the initial luminous density of the corresponding OLED has dropped from 4000 cd/m.sup.2 to 3200 cd/m.sup.2. The values for the lifetime can be converted into a value for other initial luminous densities with the aid of conversion formulae known to the person skilled in the art. The lifetime for an initial luminous density of 1000 cd/m.sup.2 is the usual figure quoted here.

(22) The data for the various OLEDs are summarised in Table 2. Examples C1-C3 are comparative examples in accordance with the prior art, while Examples I1-I5 show data for OLEDs comprising materials according to the invention.

(23) Some of the examples are explained in greater detail below in order to illustrate the advantages of the compounds according to the invention. However, it should be pointed out that this only represents a selection of the data shown in Table 2.

(24) Use of Compounds According to the Invention as Hole-transport Materials

(25) OLEDs C1-C3 are comparative examples in accordance with the prior art in which hole-transport materials SpA1 and SpNPB are employed. Examples I1-I5 show data of OLEDs in which compounds A and B according to the invention are employed.

(26) Use of compound B in blue-fluorescent OLEDs gives rise to an operating voltage which is reduced by 0.3 V compared with the prior art, which results in an increase from 7.1 to 7.5 lm/W with virtually unchanged current efficiency. The lifetime increases from 210 to 240 h through the use of compound B (Examples C1, I2).

(27) In phosphorescent green OLEDs, the use of compounds according to the invention likewise gives rise to improvements with respect to voltage and power efficiency. In particular without HATCN as interlayer, the use of compound A instead of SpA1 gives rise to a significant increase in the power efficiency of virtually 15%, with the lifetime simultaneously also increasing from 360 to 410 h (Examples C3, I5).

(28) The use of compounds according to the invention on the hole-transport side of OLEDs thus gives rise to improvements with respect to operating voltage, power efficiency and lifetime.

(29) Use of Compounds According to the Invention as Dopants

(30) Use of compound B in the emission layer of OLEDs gives rise to blue emission. Use of the layer structure HATCN 5 nm/SPA1 140 nm/NPB 20 nm/M1:B (95%:5%) 30 nm/ST1:LiQ (50%:50%) 20 nm with an aluminium layer with a thickness of 100 nm as cathode gives rise to deep-blue colour coordinates of CIE x/y=0.15/0.09 and an external quantum efficiency of 5.2% at 1000 cd/m.sup.2. The operating voltage is 4.5 V for a luminous density of 1000 cd/m.sup.2.

(31) TABLE-US-00006 TABLE 1 Structure of the OLEDs HIL HTL IL EBL EML HBL ETL Ex. thickness thickness thickness thickness thickness thickness thickness Cl HATCN SpNPB NPB M1:D1 (98.5%:1.5%) ST2:LiQ (50%:50%) 5 nm 40 nm 20 nm 30 nm 20 nm C2 SpA1 HATCN BPA1 ST1:TEG1 (90%:10%) ST1 ST1:LiQ (50%:50%) 70 nm 5 nm 20 nm 30 nm 10 nm 30 nm C3 SpA1 BPA1 IC1:TEG1 (90%:10%) ST1:LiQ (50%:50%) 70 nm 90 nm 30 nm 40 nm I1 HATCN A NPB M1:D1 (98.5%:1.5%) ST2:LiQ (50%:50%) 5 nm 40 nm 20 nm 30 nm 20 nm I2 HATCN B NPB M1:D1 (98.5%:1.5%) ST2:LiQ (50%:50%) 5 nm 40 nm 20 nm 30 nm 20 nm I3 A 70 nm HATCN BPA1 ST1:TEG1 (90%:10%) ST1 ST1:LiQ (50%:50%) 5 nm 20 nm 30 nm 10 nm 30 nm I4 B 70 nm HATCN BPA1 ST1:TEG1 (90%:10%) ST1 ST1:LiQ (50%:50%) 5 nm 20 nm 30 nm 10 nm 30 nm I5 A BPA1 IC1:TEG1 (90%:10%) ST1:LiQ (50%:50%) 70 nm 90 nm 30 nm 40 nm

(32) TABLE-US-00007 TABLE 2 Data for the OLEDs U1000 CE1000 PE1000 EQE CIE x/y at L0 L1 LT Ex. (V) (cd/A) (Im/W) 1000 1000 cd/m.sup.2 (cd/m.sup.2) % (h) C1 4.3 9.8 7.1 7.6% 0.14/0.16 6000 50 210 C2 4.2 52 39 14.5% 0.36/0.60 4000 80 330 C3 3.8 54 45 14.9% 0.36/0.60 4000 80 360 I1 4.2 9.9 7.4 7.7% 0.14/0.16 6000 50 200 I2 4.0 9.5 7.5 7.4% 0.14/0.16 6000 50 240 I3 4.0 52 41 14.3% 0.36/0.60 4000 80 340 I4 3.9 53 43 14.6% 0.36/0.60 4000 80 360 I5 3.4 55 51 15.3% 0.36/0.60 4000 80 410

(33) TABLE-US-00008 TABLE 3 Structural formulae of the materials for the OLEDs 00 01 02 03 04 05 06 07 08 09 0