Materials for organic electroluminescent devices

Abstract

The present invention relates to cyclic diazaboroles, in particular for use as triplet matrix materials in organic electroluminescent devices. The invention further relates to a method for producing the compounds according to the invention, and to electronic devices comprising same.

Claims

1. A compound of formulae (2-1), (2-2) or (2-3) ##STR00363## where the symbols and indices used are as follows: E is the same or different at each instance and is selected from the group consisting of a single bond, NR, CR.sub.2, O, S and C═O; G is the same or different at each instance and is selected from the group consisting of NR, CR.sub.2, O, S and C═O; p, q, r are the same or different at each instance and are selected from the group consisting of 0, 1 and 2; s, t are the same or different at each instance and are selected from the group consisting of 0 and 1; and where, at least one of p, r, s or t=1; or q is 0 and both Ar are an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted by one or more R radicals, and which is bonded to at least both nitrogen atoms; R is the same or different at each instance and is selected from the group consisting of H, D, F, Cl, Br, I, CN, NO.sub.2, N(Ar.sup.4)2, N(R.sup.1).sub.2, OAr.sup.4, OR.sup.1, SAr.sup.4, SR.sup.1, C(═O)Ar.sup.4, C(═O)R.sup.1, P(═O)(Ar.sup.4).sub.2, P(Ar.sup.4).sub.2, B(Ar.sup.4).sub.2, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 carbon atoms or an alkenyl group or alkynyl group having 2 to 40 carbon atoms, each of which may be substituted by one or more R.sup.1 radicals and where one or more nonadjacent CH.sub.2 groups may be replaced by R.sup.1C═CR.sup.1,C═O, C═S, C═NR.sup.1, P(═O)(R.sup.1), SO, SO.sub.2, NR.sup.1, O, S or CONR.sup.1 and where one or more hydrogen atoms may be replaced by D, F, CI, Br, I, CN or NO.sub.2, an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted in each case by one or more R.sup.1 radicals, or an aralkyl or heteroaralkyl group which has 5 to 60 aromatic ring atoms and may be substituted by one or more R.sup.1 radicals; at the same time, optionally two or more substituents R may form a monocyclic or polycyclic, aliphatic, heteroaliphatic, aromatic or heteroaromatic ring system which may be substituted by one or more R.sup.1 radicals; Ar, Ar.sup.1, Ar.sup.2, Ar.sup.3 are the same or different at each instance and are an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted by one or more R radicals, where, when q is 0, both Ar together may also be an Ar group bonded to at least both nitrogen atoms; Ar.sup.4 is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted by one or more R.sup.2 radicals; at the same time, two Ar.sup.4 radicals bonded to the same nitrogen atom or phosphorus atom may also be bridged to one another by a single bond or a bridge selected from N(R.sup.2), C(R.sup.2).sub.2, O and S; X is the same or different at each instance and is CR or N, where X is C when there is a bond to E or G thereon, and where not more than 2 X in any cycle are N; Y is the same or different at each instance and is CR, NR, O or S, where Y may also be N when one Y in the same cycle is already NR, O or S, where Y is C or N when there is a bond to E thereon; R.sup.1 is the same or different at each instance and is selected from the group consisting of H, D, F, Cl, Br, I, CN, NO.sub.2, N(R.sup.2).sub.2, OR.sup.2, SR.sup.2, C(═O)R.sup.2, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 carbon atoms or an alkenyl group or alkynyl group having 2 to 20 carbon atoms, each of which may be substituted by one or more R.sup.2 radicals and where one or more nonadjacent CH.sub.2 groups may be replaced by R.sup.2C═CR.sup.2, C═O, C═S, C═NR.sup.2, P(═O)(R.sup.2), SO, SO.sub.2, NR.sup.2, O, S or CONR.sup.2 and where one or more hydrogen atoms may be replaced by D, F, Cl, Br, I, CN or NO.sub.2, an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more R.sup.2 radicals, or an aralkyl or heteroaralkyl group which has 5 to 40 aromatic ring atoms and may be substituted by one or more R.sup.2 radicals; at the same time, it is optionally possible for two substituents R.sub.1 bonded to the same carbon atom or to adjacent carbon atoms to form a monocyclic or polycyclic, aliphatic, heteroaliphatic, aromatic or heteroaromatic ring system which may be substituted by one or more R.sup.2 radicals; and R.sup.2 is the same or different at each instance and is selected from the group consisting of H, D, F, CN, an aliphatic hydrocarbyl radical having 1 to 20 carbon atoms, or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms in which one or more hydrogen atoms may be replaced by D, F or CN or substituted by one or more alkyl groups each having 1 to 10 carbon atoms; at the same time, two or more adjacent R.sup.2 substituents together may form a mono- or polycyclic, aliphatic, aromatic or heteroaromatic ring system.

2. A compound as claimed in claim 1, characterized in that it is a compound of the formula (2) ##STR00364## where the symbols and indices have the definitions given in claim 1 and in addition: X is the same or different at each instance and is CR, where X is C when there is a bond to E or G thereon.

3. A compound as claimed in claim 1, characterized in that p and r are the same or different at each instance and are selected from the group consisting of 0 and 1, and q is 0, 1 or 2.

4. A mixture comprising at least one compound as claimed in claim 1 and at least one further compound and/or at least one solvent.

5. A method comprising incorporating the compound as claimed in claim 1 in an electronic device.

6. An electronic device comprising at least one compound as claimed in claim 1.

7. The electronic device as claimed in claim 6, characterized in that it is an organic electroluminescent device.

8. The electronic device as claimed in claim 7, wherein the electronic device comprises the compound in an emitting layer, optionally as one or more further matrix materials, in a hole transport layer or in an electron transport layer.

Description

EXAMPLES

(1) The syntheses which follow, unless stated otherwise, are conducted under a protective gas atmosphere in dried solvents. The solvents and reagents can be purchased, for example, from Sigma-ALDRICH or ABCR. For the compounds known from the literature, the corresponding CAS numbers are also reported in each case.

SYNTHESIS EXAMPLES

a) Phenyl-[2-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenyl]-amine

(2) ##STR00073##

(3) In a 500 ml flask, under protective gas, 7 g (28 mmol, 35%) of 2-bromophenyl(phenyl)amine and 8.6 g (35 mmol, 1.2 eq) of bis(pinacolato)diborane (CAS 73183-34-3) are dissolved in 120 ml of dry DMF and the mixture is degassed for 30 minutes. Subsequently, 8.2 g (84 mmol, 3.0 eq.) of potassium acetate and 690 mg (0.84 mmol, 3 mol %) of [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (CAS 95464-05-4) are added, and the mixture is heated to 90° C. overnight. After the reaction has ended, the mixture is diluted with 300 ml of toluene and extracted with water. The solvent is removed on a rotary evaporator and the solids obtained are dried. The product (6.6 g, 22 mmol, 80% of theory) is converted without further purification.

(4) In an analogous manner, it is possible to obtain the following compounds:

(5) TABLE-US-00001 No. Reactant Product Yield  1a 76%  2a 78%  3a 82%  4a 0 81%  5a 83%  6a 76%  7a 78%  8a 88%  9a 0 65% 10a 76% 11a 75% 12a 62% 13a 66% 14a 00 01 58%

b) N2,N2″-Diphenyl-2′-trimethylsilanyl-[1,1′; 3′,1″]terphenyl-2,2″-diamine

(6) ##STR00102##

(7) 20.5 g (70 mmol) of N-phenyl-2-(4°,4′,5′,5′-tetramethyl-1′,3′,2′-dioxaborolan-2-yl)-phenylamine, 21.5 g (70 mmol) of (2,6-dibromophenyl)trimethylsilane and 78.9 ml (158 mmol) of Na.sub.2CO.sub.3 (2 M solution) are suspended in 200 ml of dimethoxyethane. 1.3 g (1.1 mmol) of Pd(PPh.sub.3).sub.4 is added to this suspension, and the reaction mixture is heated under reflux for 16 h. After cooling, dichloromethane is added to the mixture, and the organic phase is removed, filtered through silica gel and recrystallized from toluene. The yield is 21.6 g (45 mmol), corresponding to 85% of theory.

(8) In an analogous manner, it is possible to obtain the following compounds:

(9) TABLE-US-00002 No. Reactant 1 Reactant 2 Product Yield  1b 03 04 05 61%  2b 06 07 08 70%  3b 09 0 80%  4b 86%  5b 79%  6b 0 75%  7b 70%  8b 74%  9b 72% 10b 0 76% 11b 69% 12b 65% 13b 0 80% 14b 61% 15b 64% 16b 0 82% 17b 63% 18b 79% 19b 73% 20b 0 70% 21b 74% 22b 64% 23b 0 64% 24b 67%

c) 8,9-Diphenyl-8H,9H-8,9-diaza-8a-borabenzo[fg]naphthacene

(10) ##STR00175##

(11) Under protective gas, 9.6 g (20 mmol) of N2,N2″-diphenyl-2′-trimethylsilanyl-[1,1′; 3′,1″]terphenyl-2,2″-diamine is dissolved in 400 ml of o-dichlorobenzene. Added to this solution are 6 g (60 mmol) of triethylamine and 300 ml (1.5 mmol) of boron trichloride, 1 M in hexane, and the reaction mixture is heated under reflux (˜180° C.) for 12 h. After cooling, the mixture is concentrated, separated by chromatography (CH.sub.2Cl.sub.2/heptane, 5:1), recrystallized from a CH.sub.2Cl.sub.2/MeOH mixture, and finally sublimed under high vacuum (p=5×10.sup.−5 mbar). The yield is 7.2 g (17 mmol), corresponding to 87% of theory.

(12) In an analogous manner, it is possible to obtain the following compounds:

(13) TABLE-US-00003 No. Reactant 4 Product Yield  1c 74%  2c 80%  3c 0 89%  4c 69%  5c 78%  6c 70%  7c 74%  8c 0 72%  9c 76% 10c 69% 11c 65% 12c 80% 13c 00 01 61% 14c 02 03 63% 15c 04 05 82% 16c 06 07 79% 17c 08 09 70% 18c 0 65% 19c 73% 20c 59% 21c 52% 22c 58%

d) 5,12-Dibromo-8,9-bis-(4-tert-butyl-phenyl)-8H,9H-8,9-diaza-8a-borabenzo[fg]naphthacene

(14) ##STR00220##

(15) 100 g (190.0 mmol) of 8,9-bis(4-tert-butylphenyl)-8H,9H-8,9-diaza-8a-borabenzo[fg]naphthacene are dissolved in 500 ml of CH.sub.2Cl.sub.2 and 150 ml of acetic acid. 34 g (190 mmol) of NBS are added to this suspension in portions and the mixture is stirred in the dark for 9 h. Thereafter, water/ice is added and the solids are removed and washed with ethanol. The residue is recrystallized from toluene. The yield is 98 g (142 mmol), corresponding to 76% of theory.

(16) In an analogous manner, it is possible to obtain the following compounds:

(17) TABLE-US-00004 No. Reactant 4 Product Yield 1d 75% 2d 81% 3d 83% 4d 62% 5d 0 65% 6d 56% 7d 53%

(18) The following compounds can be obtained analogously to method b:

(19) TABLE-US-00005 No. Reactant 1 Reactant 2 Product Yield 19b 61% 20b 0 70% 21b 76% 22b 70% 23b 71% 24b 0 78% 25b 65% 26b 66% 27b 0 74% 28b 76% 29b 59%

e) 8-(4,6-Diphenyl-[1,3,5]triazin-2-yl)-9-phenyl-8H,9H-8,9-diaza-8a-borabenzo[fg]naphthacene

(20) ##STR00268##

(21) 4.3 g of NaH, 60% in mineral oil, (107 mmol) is dissolved in 300 ml of dimethylformamide under a protective atmosphere. 36 g (107 mmol) of 8-phenyl-8H,9H-8,9-diaza-8a-borabenzo[fg]naphthacene is dissolved in 250 ml of DMF and added dropwise to the reaction mixture. After 1 h at room temperature, a solution of 28.5 g (107 mmol) of 2-chloro-4,6-diphenyl-[1,3,5]triazine in 200 ml of THF is added dropwise. The reaction mixture is stirred at room temperature for 12 h and then poured onto ice. After warming to room temperature, the solids that precipitate out are filtered and washed with ethanol and heptane. The residue is subjected to hot extraction with toluene, recrystallized from toluene/n-heptane and finally sublimed under high vacuum. The yield is 36 g (62 mmol; 60%); purity 99.9%.

(22) In an analogous manner, it is possible to obtain the following compounds:

(23) TABLE-US-00006 No. Reactant 1 Reactant 2 Product Yield 1e 0 61% 2e 58% 3e 62% 4e 0 61% 5e 60% 6e 58%

f) 8-[3-(4,6-Diphenyl-[1,3,5]triazin-2-yl)phenyl]-9-phenyl-8H,9H-8,9-diaza-8a-borabenzo[fg]naphthacene

(24) ##STR00287##

(25) 22.5 g (66 mmol) of 8-phenyl-8H,9H-8,9-diaza-8a-borabenzo[fg]naphthacene, 28.5 g (73 mmol) of 3-bromo-(4,6-diphenyl-[1,3,5]triazin-2-yl)benzene and 19 g of NaOtBu are suspended in 1 l of p-xylene. To this suspension are added 0.3 g (1.33 mmol) of Pd(OAc).sub.2 and 1.0 ml of a 1M tri-tert-butylphosphine solution in toluene. The reaction mixture is heated under reflux for 16 h. After cooling, methylene chloride is added, and the organic phase is removed, washed three times with 200 ml of water and then concentrated to dryness. The residue is subjected to hot extraction with toluene, recrystallized from toluene and finally sublimed under high vacuum. The purity is 99.9%. The yield is 29 g (45 mmol; 70%).

(26) In an analogous manner, it is possible to obtain the following compounds:

(27) TABLE-US-00007 No. Reactant 1 Reactant 2 Product Yield  1f 0 61%  2f 58%  3f 62%  4f 61%  5f 00 01 02 72%  6f 03 04 05 80%  7f 06 07 08 69%  8f 09 0 84%  9f 80% 10f 81% 11f 0 76% 12f 77% 13f 76% 14f 78% 15f 0 65% 16f 60% 17f 62% 18f 0 66%
Production of the OLEDs

(28) Examples I1 to I10 which follow (see Table 1) present the use of the materials of the invention in OLEDs.

(29) Pretreatment for Examples I1-I10:

(30) Glass plaques coated with structured ITO (indium tin oxide) of thickness 50 nm are treated prior to coating with an oxygen plasma, followed by an argon plasma. These plasma-treated glass plaques form the substrates to which the OLEDs are applied.

(31) The OLEDs basically have the following layer structure: substrate/hole injection layer (HIL)/hole transport layer (HTL)/electron blocker layer (EBL)/emission layer (EML)/optional hole blocker layer (HBL)/electron transport layer (ETL)/optional electron injection layer (EIL) and finally a cathode. The cathode is formed by an aluminum layer of thickness 100 nm. The exact structure of the OLEDs can be found in table 1. The materials required for production of the OLEDs are shown in Table 2.

(32) All materials are applied by thermal vapor deposition in a vacuum chamber. In this case, the emission layer always consists of at least one matrix material (host material) and an emitting dopant (emitter) which is added to the matrix material(s) in a particular proportion by volume by co-evaporation. Details given in such a form as EG1:IC2:TEG1 (44%:44%:12%) mean here that the material EG1 is present in the layer in a proportion of 44%, IC2 in a proportion of 44%, and TEG1 in a proportion of 12%, Analogously, the electron transport layer may also consist of a mixture of two materials.

(33) The OLEDs are characterized in a standard manner. The electroluminescence spectra are determined at a luminance of 1000 cd/m.sup.2, and the CIE 1931 x and y color coordinates are calculated therefrom.

(34) Use of Materials of the Invention in OLEDs

(35) The materials of the invention can be used in the emission layer in phosphorescent green OLEDs. The inventive compounds IV1 to IV10 are used in Examples 11 to 110 as matrix material in the emission layer. The color coordinates of the electroluminescence spectra of the OLEDs from these examples are CIEx=0.33 and CIEy=0.63. The materials are thus suitable for use in the emission layer of green OLEDs. In addition, the materials of the invention can be used successfully in the hole blocker layer (HBL) or in the electron blocker layer (EBL). This is shown in Examples I11 and I12. Here too, the color coordinates of the spectrum of the OLED are CIEx=0.33 and CIEy=0.63.

(36) TABLE-US-00008 TABLE 1 Structure of the OLEDs HIL HTL EBL EML HBL ETL EIL Ex. thickness thickness thickness thickness thickness thickness thickness I1 HATCN SpMA1 SpMA2 IV1:IC2:TEG1 ST2 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm I2 HATCN SpMA1 SpMA2 IV2:IC2:TEG1 ST2 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm I3 HATCN SpMA1 SpMA2 IV3:IC2:TEG1 ST2 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm I4 HATCN SpMA1 SpMA2 IV4:IC2:TEG1 ST2 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm I5 HATCN SpMA1 SpMA2 IV5:IC2:TEG1 ST2 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm I6 HATCN SpMA1 SpMA2 IV6:IC2:TEG1 ST2 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm I7 HATCN SpMA1 SpMA2 IV7:IC1:TEG1 ST2 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm I8 HATCN SpMA1 SpMA2 IV8:IC1:TEG1 ST2 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm I9 HATCN SpMA1 SpMA2 IV9:IC2:TEG1 ST2 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm I10 HATCN SpMA1 SpMA2 IC1:IC2:TEG1 ST2 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm I11 HATCN SpMA1 SpMA2 IC1:IC2:TEG1 IV1 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm I12 HATCN SpMA1 IV8 IV9:IC2:TEG1 ST2 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm I13 HATCN SpMA1 IV8 IV11:IC2:TEG1 ST2 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm I14 HATCN SpMA1 IV8 IV12:IC2:TEG1 ST2 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm I15 HATCN SpMA1 IV8 IV13:IC2:TEG1 ST2 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm I15 HATCN SpMA1 IV8 IV14:IC2:TEG1 ST2 ST2:LiQ LiQ 1 nm 5 nm 230 nm 20 nm (44%:44%:12%) 30 nm 10 nm (50%:50%) 30 nm

(37) TABLE-US-00009 TABLE 2 Structural formulae of the materials for the OLEDs 0 0 IV14