Organic Electroluminescent Element And Novel Iridium Complex

Abstract

An organic electronic device comprising at least one hole-transport material and/or at least one electron/exciton blocker material, wherein said at least one hole-transport material and/or said at least one electron/exciton blocker material is an Ir metal-carbene complex comprising one, two or three specific bidentate azabenzimidazole ligands; a hole transport layer or an electron/exciton blocking layer, comprising at least one Ir metal-carbene complex, comprising one, two or three specific bidentate azabenzimidazole ligands; an apparatus selected from the group consisting of stationary visual display units, mobile visual display units, illumination units, units in items of clothing, units in furniture and units in wallpaper, comprising the organic electronic device of the present invention or the hole transport layer or the electron/exciton blocking layer of the present invention; and the use of an Ir metal-carbene complex comprising one, two or three specific bidentate azabenzimidazole ligands according to the present invention as hole-transport material and/or electron/exciton blocker material.

Claims

1.-15. (canceled)

16. An organic electronic device comprising at least one hole-transport material and/or at least one electron/exciton blocker material, wherein said at least one hole-transport material and/or said at least one electron/exciton blocker material is an Ir metal-carbene complex comprising one, two or three bidentate ligands of formula (I) and/or (I) ##STR00105## wherein R.sup.1, R.sup.2 and R.sup.3 are each independently hydrogen, deuterium, a linear or branched alkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 1 to 20 carbon atoms and/or heteroatoms, a substituted or unsubstituted cycloalkyl radical optionally bearing at least one functional group and having from 3 to 20 carbon atoms, a substituted or unsubstituted heterocyclo alkyl radical interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 3 to 20 carbon atoms and/or heteroatoms, a substituted or unsubstituted aryl radical optionally bearing at least one functional group and having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl radical interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 5 to 18 carbon atoms and/or heteroatoms, or a group with donor or acceptor action; or R.sup.1 and R.sup.2, or R.sup.2 and R.sup.3, form, independently of each other, together with a carbon atom to which they are bonded, an optionally substituted saturated, unsaturated, or aromatic ring optionally interrupted by at least one heteroatom and having a total of from 5 to 18 carbon atoms and/or heteroatoms, and may optionally be fused to at least one further optionally substituted saturated or unsaturated or aromatic ring optionally interrupted by at least one heteroatom and having a total of from 5 to 18 carbon atoms and/or heteroatoms; A.sup.1 is CR.sup.4 or N; A.sup.2 is CR.sup.5 or N; A.sup.3 is CR.sup.6 or N; A.sup.4 is CR.sup.7 or N; A.sup.1 is CR.sup.4 or N; A.sup.2 is CR.sup.5 or N; A.sup.3 is CR.sup.6 or N; A.sup.4 is CR.sup.7 or N; R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.4, R.sup.5, R.sup.6, and R.sup.7 are each independently hydrogen, deuterium, a linear or branched alkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 1 to 20 carbon atoms and/or heteroatoms, a substituted or unsubstituted cycloalkyl radical optionally bearing at least one functional group and having from 3 to 20 carbon atoms, a substituted or unsubstituted heterocyclo alkyl radical interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 3 to 20 carbon atoms and/or heteroatoms, a substituted or unsubstituted aryl radical optionally bearing at least one functional group and having from 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl radical interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 5 to 18 carbon atoms and/or heteroatoms, or a group with donor or acceptor action; or R.sup.4 and R.sup.5, R.sup.5 and R.sup.6, R.sup.6 and R.sup.7, R.sup.4 and R.sup.5, R.sup.5 and R.sup.6, or R.sup.6 and R.sup.7, form, independently of each other, together with the carbon atoms to which they are bonded, an optionally substituted saturated, unsaturated, or aromatic ring, which has a total of from 5 to 18 carbon atoms and/or heteroatoms, is optionally interrupted by at least one heteroatom, and may optionally be fused to at least one further optionally substituted saturated or unsaturated or aromatic ring optionally interrupted by at least one heteroatom and having a total of from 5 to 18 carbon atoms and/or heteroatoms.

17. The organic electronic device according to claim 16, wherein the at least one hole-transport material comprising the Ir metal-carbene complex comprising one, two or three bidentate ligands of formula (I) and/or (I) is present in a hole transport layer of the organic electronic device and/or the at least one electron/exciton blocker material, comprising the Ir metal-carbene complex comprising one, two or three bidentate ligands of formula (I) and/or (I) is present in an electron/exciton-blocking layer of the organic electronic device.

18. The organic electronic device according to claim 16, wherein the organic electronic device is selected from organic light-emitting diodes (OLED), light-emitting electrochemical cells (LEEC), organic photovoltaic cells (OPV) and organic field-effect transistors (OFET).

19. The organic electronic device according to claim 18, wherein the OLED comprises (a) an anode, (b) a cathode, (c) a light-emitting layer between the anode and the cathode, (d) at least one layer, selected from a hole-transport layer (d1) and an electron/exciton blocking layer (d2), wherein the at least one hole-transport material, comprising the Ir metal-carbene complex comprising one, two or three bidentate ligands of formula (I) and/or (I) is present in the hole-transport layer of the OLED and/or the at least one electron/exciton blocker material, comprising the Ir metal-carbene complex comprising one, two or three bidentate ligands of formula (I) and/or (I) is present in the electron/exciton blocking layer of the OLED.

20. The organic electronic device according to claim 16, wherein the radicals, groups and symbols in the at least two ligands of formulae (I) and (I) have the following meanings: R.sup.1, R.sup.2 and R.sup.3 are each independently hydrogen, a linear or branched alkyl radical having from 1 to 6 carbon atoms, a substituted or unsubstituted aryl radical having from 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl radical having a total of from 5 to 18 carbon atoms and/or heteroatoms, or a group with donor or acceptor action selected from the group consisting of halogen radicals, CF.sub.3, CN, SiPh.sub.3 and SiMe.sub.3; or R.sup.1 and R.sup.2, or R.sup.2 and R.sup.3, form, independently of each other, together with a carbon atom to which they are bonded, an optionally substituted saturated, unsaturated, or aromatic ring optionally interrupted by at least one heteroatom and having a total of from 5 to 18 carbon atoms and/or heteroatoms, and may optionally be fused to at least one further optionally substituted saturated or unsaturated or aromatic ring optionally interrupted by at least one heteroatom and having a total of from 5 to 18 carbon atoms and/or heteroatoms; A.sup.1 is CR.sup.4; A.sup.2 is CR.sup.5; A.sup.3 is CR.sup.6; A.sup.4 is CR.sup.7; A.sup.1 is CR.sup.4 or N; A.sup.2 is CR.sup.5 or N; A.sup.3 is CR.sup.6 or N; A.sup.4 is CR.sup.7 or N; R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.4, R.sup.5, R.sup.6 and R.sup.7 are each independently hydrogen, deuterium, a linear or branched alkyl radical optionally bearing at least one functional group, optionally interrupted by at least one heteroatom, and having a total of from 1 to 20 carbon and/or heteroatoms, a substituted or unsubstituted aryl radical, having from 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl radical, having a total of from 5 to 18 carbon atoms and/or heteroatoms, a group with donor or acceptor action selected from halogen radicals, CF.sub.3, CN and SiMe.sub.3; or R.sup.4 and R.sup.5, R.sup.5 and R.sup.6, R.sup.6 and R.sup.7, R.sup.4 and R.sup.5, R.sup.5 and R.sup.6, or R.sup.6and R.sup.7, form, independently of each other, with the carbon atoms to which they are bonded, an optionally substituted saturated, unsaturated, or aromatic ring, which is optionally interrupted by at least one heteroatom, has a total of from 5 to 18 carbon atoms and/or heteroatoms, and may optionally be fused by at least one further optionally substituted saturated or unsaturated aromatic ring optionally interrupted by at least one heteroatom, and having a total of from 5 to 18 carbon atoms and/or heteroatoms.

21. The organic electronic device according to claim 16, wherein the Ir metal-carbene complex has one of the following formulae (II), (II) or (II) ##STR00106## wherein R.sup.1, R.sup.2 and R.sup.3 are each independently hydrogen, deuterium, a linear or branched alkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 1 to 20 carbon atoms and/or heteroatoms, a substituted or unsubstituted cycloalkyl radical optionally bearing at least one functional group and having from 3 to 20 carbon atoms, a substituted or unsubstituted heterocyclo alkyl radical interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 3 to 20 carbon atoms and/or heteroatoms, a substituted or unsubstituted aryl radical optionally bearing at least one functional group and having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl radical interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 5 to 18 carbon atoms and/or heteroatoms, or a group with donor or acceptor action; or R.sup.1 and R.sup.2, or R.sup.2 and R.sup.3, form, independently of each other, together with a carbon atom to which they are bonded, an optionally substituted saturated, unsaturated, or aromatic ring optionally interrupted by at least one heteroatom and having a total of from 5 to 18 carbon atoms and/or heteroatoms, which may optionally be fused to at least one further optionally substituted saturated, unsaturated, aromatic ring optionally interrupted by at least one heteroatom and having a total of from 5 to 18 carbon atoms and/or heteroatoms; A.sup.1 is CR.sup.4 or N; A.sup.2 is CR.sup.5 or N; A.sup.3 is CR.sup.6 or N; A.sup.4 is CR.sup.7 or N; A.sup.1 is CR.sup.4 or N; A.sup.2 is CR.sup.5 or N; A.sup.3 is CR.sup.6 or N; A.sup.4 is CR.sup.7 or N; R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.4, R.sup.5, R.sup.6, and R.sup.7 are each independently hydrogen, deuterium, a linear or branched alkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 1 to 20 carbon atoms and/or heteroatoms, a substituted or unsubstituted cycloalkyl radical optionally bearing at least one functional group and having from 3 to 20 carbon atoms, a substituted or unsubstituted heterocyclo alkyl radical interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 3 to 20 carbon atoms and/or heteroatoms, a substituted or unsubstituted aryl radical optionally bearing at least one functional group and having from 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl radical interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 5 to 18 carbon atoms and/or heteroatoms, or a group with donor or acceptor action; or R.sup.4 and R.sup.5, R.sup.5 and R.sup.6, or R.sup.6 and R.sup.7, form, independently of each other, together with the carbon atoms to which they are bonded, an optionally substituted saturated, unsaturated, aromatic ring, which has a total of from 5 to 18 carbon atoms and/or heteroatoms, is optionally interrupted by at least one heteroatom, and may optionally be fused to at least one further optionally substituted saturated or unsaturated or aromatic ring optionally interrupted by at least one heteroatom and having a total of from 5 to 18 carbon atoms and/or heteroatoms; n is 1, 2 or 3; L is a monoanionic bidentate ligand; o is 0, 1 or 2, where, when o=2, the L ligands may be the same or different; n is 1 or 2; n is 1 or 2; wherein the sum of n+n is 2 or 3; o is 0 or 1; and wherein the sum of n+o in formulae (II) and (II) and the sum of n+n+and o in formula (II) is 3, with the proviso that n in formula (II) and (II) is at least 1 and n, as well as n in formula (II) are at least 1.

22. The organic electronic device according to claim 21, wherein n is 1 or 2; and n is 1 or 2; wherein the sum of n+n is 3.

23. The organic electronic device according to claim 22, wherein the Ir metal-carbene complex has one of the following formulae (IIa), (IIa), (IIa) or (IIa) ##STR00107##

24. The organic electronic device according to claim 16, wherein the Ir metal-carbene complex is employed in combination with at least one metal oxide.

25. The organic electronic device according to claim 19, wherein the light-emitting layer comprises at least one emitter material, which has an emission maximum .sub.max of from 400 to 500 nm.

26. The organic electronic device according to claim 19, wherein the light-emitting layer comprises at least one phosphorescent emitter material.

27. The organic electronic device according to claim 25, wherein the at least one emitter material is a compound of formula (IV) ##STR00108## wherein M is Ir; n is 1, 2 or 3; A.sup.9 is CR.sup.9 or N; A.sup.10 is CR.sup.10 or N; A.sup.11 is CR.sup.11 or N; A.sup.12 is CR.sup.12 or N; where 2 of A.sup.9, A.sup.10, A.sup.11 and A.sup.12 are nitrogen atoms and at least one carbon atom is present between two nitrogen atoms in the ring; R.sup.8 is a linear or branched alkyl radical having from 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl radical having from 3 to 20 carbon atoms, a substituted or unsubstituted aryl radical having from 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl radical having a total of from 5 to 18 carbon atoms and/or heteroatoms, R.sup.9, R.sup.10, R.sup.11 and R.sup.12 are each independently hydrogen, a linear or branched alkyl radical having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl radical having from 3 to 20 carbon atoms, a substituted or unsubstituted aryl radical having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl radical having a total of 5 to 18 carbon atoms and/or heteroatoms, or R.sup.10 and R.sup.11 form, together with the carbon atoms to which they are bonded, an optionally substituted, unsaturated ring optionally interrupted by at least one heteroatom and having a total of 5 to 18 carbon atoms and/or heteroatoms; A.sup.5 is CR.sup.13 or N; A.sup.6 is CR.sup.14 or N; A.sup.7 is CR.sup.15 or N;, A.sup.8 is CR.sup.16 or N; R.sup.13, R.sup.14, R.sup.15 and R.sup.16 are each independently hydrogen, a linear or branched alkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 1 to 20 carbon atoms and/or heteroatoms, a substituted or unsubstituted cycloalkyl radical optionally bearing at least one functional group and having from 3 to 20 carbon atoms, a substituted or unsubstituted heterocyclo alkyl radical, interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 3 to 20 carbon atoms and/or heteroatoms, a substituted or unsubstituted aryl radical optionally bearing at least one functional group and having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl radical interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 5 to 18 carbon atoms and/or heteroatoms, or a group with donor or acceptor action; L is a monoanionic bidentate ligand; o is 0, 1 or 2; and n+o is 3.

28. The organic electronic device according to claim 16, wherein the at least one hole transport material and/or at least one electron/exciton blocker material is in a hole transport layer or an electron/exciton blocking layer.

29. An apparatus selected from the group consisting of stationary visual display units, mobile visual display units, illumination units, units in items of clothing, units in furniture and units in wallpaper, wherein the apparatus comprises the organic electronic device according to claim 16.

30. A hole-transport and/or electron/exciton blocker material, wherein said at least one hole-transport material and/or said at least one electron/exciton blocker material is an Ir metal-carbene complex comprising one, two or three bidentate ligands of formula (I) and/or (I) ##STR00109## wherein R.sup.1, R.sup.2 and R.sup.3 are each independently hydrogen, deuterium, a linear or branched alkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 1 to 20 carbon atoms and/or heteroatoms, a substituted or unsubstituted cycloalkyl radical optionally bearing at least one functional group and having from 3 to 20 carbon atoms, a substituted or unsubstituted heterocyclo alkyl radical interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 3 to 20 carbon atoms and/or heteroatoms, a substituted or unsubstituted aryl radical optionally bearing at least one functional group and having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl radical interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 5 to 18 carbon atoms and/or heteroatoms, or a group with donor or acceptor action; or R.sup.1 and R.sup.2, or R.sup.2 and R.sup.3, form, independently of each other, together with a carbon atom to which they are bonded, an optionally substituted saturated, unsaturated, or aromatic ring optionally interrupted by at least one heteroatom and having a total of from 5 to 18 carbon atoms and/or heteroatoms, and may optionally be fused to at least one further optionally substituted saturated or unsaturated or aromatic ring optionally interrupted by at least one heteroatom and having a total of from 5 to 18 carbon atoms and/or heteroatoms; A.sup.1 is CR.sup.4 or N; A.sup.2 is CR.sup.5 or N; A.sup.3 is CR.sup.6 or N; A.sup.4 is CR.sup.7 or N; A.sup.1 is CR.sup.4 or N; A.sup.2 is CR.sup.5 or N; A.sup.3 is CR.sup.6 or N; A.sup.4 is CR.sup.7 or N; R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.4, R.sup.5, R.sup.6, and R.sup.7 are each independently hydrogen, deuterium, a linear or branched alkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 1 to 20 carbon atoms and/or heteroatoms, a substituted or unsubstituted cycloalkyl radical optionally bearing at least one functional group and having from 3 to 20 carbon atoms, a substituted or unsubstituted heterocyclo alkyl radical interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 3 to 20 carbon atoms and/or heteroatoms, a substituted or unsubstituted aryl radical optionally bearing at least one functional group and having from 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl radical interrupted by at least one heteroatom, optionally bearing at least one functional group, and having a total of from 5 to 18 carbon atoms and/or heteroatoms, or a group with donor or acceptor action; or R.sup.4 and R.sup.5, R.sup.5 and R.sup.6, R.sup.6 and R.sup.7, R.sup.4 and R.sup.5, R.sup.5 and R.sup.6, or R.sup.6 and R.sup.7, form, independently of each other, together with the carbon atoms to which they are bonded, an optionally substituted saturated, unsaturated, or aromatic ring, which has a total of from 5 to 18 carbon atoms and/or heteroatoms, is optionally interrupted by at least one heteroatom, and may optionally be fused to at least one further optionally substituted saturated or unsaturated or aromatic ring optionally interrupted by at least one heteroatom and having a total of from 5 to 18 carbon atoms and/or heteroatoms.

31. A hole transport layer or an electron/exciton blocking layer comprising the hole-transport and/or electron/exciton blocker material of claim 30.

32. An apparatus selected from the group consisting of stationary visual display units; mobile visual display units, illumination units, units in items of clothing, units in furniture and units in wallpaper, wherein the apparatus comprises the hole-transport and/or electron/exciton blocker material of claim 30.

Description

APPLICATION EXAMPLES

Synthesis of BE-12

[0178] ##STR00097##

[0179] Synthesis of 5,6,7,8-tetrahydroquinoxalin-2-ol. 33.2 g (0.30 mol) of glycinamide hydrochloride are suspended under nitrogen in 120 ml of methanol and cooled down to below 30 C. 33.6 g (0.30 mol) of 1,2-cyclohexandione are dissolved in 120 ml of methanol, cooled to ice-bath temperature, and added to the suspension. The resulting white suspension is slowly treated with 60 ml of 12.5N NaOH at a temperature below 30 C. After addition, the temperature is slowly raised up to room temperature, treated with 40 ml of concentrated HCl, followed by the addition of 11 g of sodium bicarbonate. The resulting beige suspension is filtered and the solid washed with water, and further stirred three times in 200 ml of water. The solid is dried and further recrystallized from 2 l of ethanol, followed by drying under vacuum, giving the title product as off-white solid (yield: 24 g (54%)). .sup.1-NMR (400 MHz, MeOD): =1.78-1.92 (m, 4 H), 2.61-2.73 (m, 4 H), 7.88 (s, 1 H).

##STR00098##

[0180] Synthesis of 3-bromo-5,6,7,8-tetrahydroquinoxalin-2-ol. 30.0 g (0.20 mol) of 5,6,7,8-tetrahydro-quinoxalin-2-ol are suspended under nitrogen in 300 ml of chloroform and 16.6 g (0.21 mol) of pyridine. 32 g (0.20 mol) of bromine are slowly added during one hour at a maximum temperature of 4 C. The yellow suspension is further stirred and the temperature slowly raised to 0 C. The yellow solution is diluted with water and extraction done with 500 ml of dichloromethane. The organic phase is further extracted four times with 200 ml of water, dried with sodium sulfate, providing a clear yellowish solution. Dilution with 600 ml of cyclohexane gives a white precipitate. The suspension is filtered, the solid further washed with 100 ml of cyclohexane and dried under vacuum, giving the title product as a white solid (yield: 45.8 g (75%)). .sup.1H-NMR (400 MHz, MeOD): =1.78-1.90 (m, 4 H), 2.54-2.70 (m, 4 H).

##STR00099##

[0181] Synthesis of 2,3-dichloro-5,6,7,8-tetrahydroquinoxaline. 21.9 g (95.6 mmol) of 3-bromo-5,6,7,8-tetrahydroquinoxalin-2-ol are suspended at room temperature under nitrogen in 124.6 g (0.81 mol) of POCl.sub.3, followed by the addition of 45.7 g (0.48 mol) trimethylammonium chloride. The suspension is heated under reflux for two hours. The beige light turbid suspension is cooled down to 50 C. and poured into 500 ml of water. The mixture is further stirred during 15 minutes followed by filtration and subsequent washing of the solid with a large amount of water. The solid is dried under vacuum and recrystallized from cold ethanol giving the title product as off-white solid (yield: 10.2 g (53%)). Melting point: 93-94 C. .sup.1H-NMR (400 MHz, MeOD): =1.89-1.99 (m, 4 H), 2.87-2.96 (m, 4 H).

##STR00100##

[0182] Synthesis of N2,N3-diphenyl-5,6,7,8-tetrahydroquinoxaline-2,3-diamine. 28.4 g (0.14 mol) of 2,3-dichloro-5,6,7,8-tetrahydroquinoxaline are suspended under nitrogen in 260 g (2.8 mol) of aniline and the mixture heated at 148 C. for six hours. 250 ml of methanol are added and the mixture cooled down to 10 C. at which point crystallization started. The mixture is further stirred at 5 C. during 15 minutes, followed by filtration, washing with methanol, and drying. The solid is two times stirred in 120 ml of hexane, two times washed with 100 ml of hexane, filtered and dried under vacuum. The solid is recrystallized from 200 mol of ethanol giving the title product as a off-white solid (yield: 36.1 g (82%)). Melting point: 145-146 C. .sup.1H-NMR (400 MHz, d.sub.6-DMSO): =1.74-1.84 (m, 4 H), 2.60-2.70 (m, 4 H), 6.93 (t, 2 H), 7.29 (d, 4 H), 8.34 (br. s, 2 H).

##STR00101##

[0183] Synthesis of 2-ethoxy-1,3-diphenyl-5,6,7,8-tetrahydro-2H-imidazo[4,5-b]quinoxaline. 15.8 g (0.05 mol) of N2,N3-diphenyl-5,6,7,8-tetrahydroquinoxaline-2,3-diamine are suspended under nitrogen in 148.2 g (1.0 mol) of triethyl orthoformate and heated up to 120 C. Heating is continued for 27 hours, followed by the addition of 50 g of triethyl orthoformate, and stirring continued for four hours at the same temperature, providing a red brownish suspension. The suspension is filtered and the remaining filtrate concentrated under vacuum giving 19.6 g of a brownish oil. The oil is stirred in hot ethanol, cooled down and further stirred in an ice-batch during one hour. The solid is filtered off and further washed with 40 ml of cold ethanol giving the title product as light beige solid (yield: 14.5 g (78%)). .sup.1H-NMR (400 MHz, d.sub.6-DMSO): =0.90 (t, 3 H), 1.81 (br. m, 4 H), 2.71 (br. M, 4 H), 3.15 (q, 2 H), 7.16 (t, 2 H), 7.46 (t, 4 H), 7.68 (s, 1 H), 8.08 (d, 4 H).

##STR00102##

[0184] Synthesis of complex BE-12. 9.00 g (24.2 mmol) of 2-ethoxy-1,3-diphenyl-5,6,7,8-tetrahydro-2H -imidazo[4,5-b]quinoxaline and 2.03 g (3.0 mmol) of chloro(1,5-cyclooctadiene)iridium(I) dimer are suspended under argon in 90 ml of o-xylene. The suspension is four times evacuated and back-filled with argon, followed by heating at 132 C. during four hours. The brown solution is diluted with 150 ml of toluene, followed by filtration an washing with 50 ml of toluene. The solid is stirred in 30 ml toluene, followed by stirring three times with 30 ml of ethanol. Stirring in toluene and ethanol is repeated two times, followed by stirring and washing with hexane providing a yellow solid. The solid is recrystallized from 150 ml of 7:3-toluene/2-butanone mixture and washed with the same solvent mixture, followed by ethanol washings, and drying under vacuum, giving the title product as a yellow solid (yield: 4.1 g (58%)). .sup.1H-NMR (400 MHz, CD.sub.2Cl.sub.2): =1.98 (m, 12 H), 2.68-2.80 (m, 3 H), 2.82-2.92 (m, 3 H), 3,08-3.28 (m, 6 H), 6.41-7.21 (m, 24 H), 8.79 (d, 3 H).

Synthesis of IIa and IIa

[0185] The synthesis of IIa has been described in WO2012172482. Separation of the crude reaction mixture by column chromatography yields the two major isomers IIa and IIa in pure form. Isomerization as described in WO2012172482 results in a 90:10 mixture of IIa and IIa which can be used as mixture or also separated by column chromatography. Device data of pure isomers as well as mixtures of these isomers are given below.

Diode Examples

[0186] The ITO substrate used as the anode is cleaned first with commercial detergents for LCD production (Deconex 20ONS, and 25ORGAN-ACID neutralizing agent) and then in an acetone/isopropanol mixture in an ultrasound bath. To eliminate possible organic residues, the substrate is exposed to a continuous ozone flow in an ozone oven for a further 25 minutes. This treatment also improves the hole injection properties of the ITO. Next, the hole injection layer Plexcore AJ20-1000 is spun on from solution.

[0187] Thereafter, the organic materials specified below are applied by vapor deposition to the cleaned substrate at about 10.sup.7-10.sup.9 mbar at a rate of approx. 0.5-5 nm/min.

[0188] All ratios mentioned are weight ratios.

[0189] Voltage (V), efficacy (Im/W) and External Quantum Efficiency (EQE) (%) for the devices were measured at 300 cd/m.sup.2, whereas the measured values of lifetime of the devices of Comparative Application Examples are set to 100.

I Comparison of the External Quantum Efficiency (EQE) of Devices Comprising Ir(DPBIC).sub.3 as Electron/Exciton Blocking Layer; as Electron/Exciton Blocking Layer and as Co-Host and as Electron/Exciton Blocking Layer and in the Hole-Transport Layer with Devices Comprising Compound IIa as Electron/Exciton Blocking Layer; as Electron/Exciton Blocking Layer and as Co-Host and as Electron/Exciton Blocking Layer and in the Hole-Transport Layer

Device 1: Compound IIa as Electron/Exciton Blocking Layer and Compound IIa as Electron/Exciton Blocking Layer and as Co-Host

[0190] HIL Plexcore AJ20-100010 nm Ir(DPBIC).sub.3:MoO.sub.3 (50:50)10 nm X140 nm BE-12/SH-3/X2 (10:85:5)5 nm SH-325 nm ETM-2:Liq (50:50)4 nm KF100 nm Al

TABLE-US-00001 Volt- Exam- age LumEff EQE ple X1 X2 [V] [lm/W] [%] CIE.sub.x,y Device Ir(DPBIC).sub.3 Ir(DPBIC).sub.3 4.7 19.5 17.0 0.16; 0.28 1.1.sup.1) Device IIa Ir(DPBIC).sub.3 4.5 21.0 17.9 0.16; 0.27 1.2 Device IIa IIa 4.6 20.8 17.9 0.16; 0.28 1.3 .sup.1)Comparative example

Device 2: Compound of Formula IIa (Isomeric Mixture) as Electron/Exciton Blocking Layer and in the Hole Transport Layer

[0191] HIL Plexcore AJ20-100010 nm X1:MoO.sub.3 (50:50)10 nm X140 nm BE-1/SH-3/Ir(DPBIC).sub.3 (10:85:5)5 nm SH-325 nm ETM-2:Liq (50:50)4 nm KF100 nm Al

TABLE-US-00002 Voltage LumEff EQE Example X1 [V] [Im/W] [%] CIE.sub.x, y Device 2.1.sup.1) Ir(DPBIC).sub.3 5.0 17.3 14.9 0.17; 0.30 Device 2.2 IIa (75:25).sup.2) 4.7 20.8 17.5 0.16; 0.29 .sup.1)Comparative example .sup.2)75% by weight IIa and 25% by weight IIa
II Comparison of the External Quantum Efficiency (EQE) and the Lifetime (LT.sub.50) of Devices Comprising Ir(DPBIC).sub.3 as Electron/Exciton Blocking Layer; as Electron/Exciton Blocking Layer and as Co-host and as Electron/Exciton Blocking Layer and in the Hole-Transport Layer With Devices Comprising Compound IIa or Compound IIa as Electron/Exciton Blocking Layer; as Electron/Exciton Blocking Layer and as Co-Host and as Electron/Exciton Blocking Layer and in the Hole-Transport Layer

Device 3: Compound IIa (Isomeric Mixture) as Electron/Exciton Blocking Layer

[0192] HIL Plexcore AJ20-100010 nm Ir(DPBIC).sub.3:MoO.sub.3 (90:10)10 nm X140 nm BE-1/SH-1 (10:90)5 nm SH-120 nm ETM-1:Liq (50:50)2 nm KF100 nm Al

TABLE-US-00003 Voltag EQE LT.sub.50 Example X1 [V] [%] CIE.sub.x, .sub.y [%] Device 3.1.sup.1) Ir(DPBIC).sub.3 4.9 15.1 0.17; 0.31 100 Device 3.2 IIa (90:10).sup.2) 5.1 15.4 0.17; 0.31 108 .sup.1)Comparative example .sup.2)90% by weight IIa and 10% by weight IIa

Device 4: Compound IIa (Isomeric Mixture) as Electron/Exciton Blocking Layer

[0193] HIL Plexcore AJ20-100010 nm Ir(DPBIC).sub.3:MoO.sub.3 (90:10)10 nm X140 nm BE-1/SH-1/Ir(DPBIC).sub.3 (30:60:10)5 nm SH-120 nm ETM-1:Liq (50:50)2 nm KF100 nm Al

TABLE-US-00004 Voltage LumEff EQE LT.sub.50 Example X1 [V] [lm/W] [%] CIE.sub.x,y [%] Device 4.1.sup.1) Ir(DPBIC).sub.3 4.1 21.3 13.3 0.18; 0.36 100 Device 4.2 IIa 3.6 31.1 17.1 0.18; 0.37 118 (90:10).sup.2) .sup.1)Comparative example .sup.2)90% by weight IIa and 10% by weight IIa

Device 5: Compound IIa as Electron/Exciton Blocking Layer and Compound IIa as Electron/Exciton Blocking Layer and as Co-Host

[0194] HIL Plexcore AJ20-100010 nm Ir(DPBIC).sub.3:MoO.sub.3 (50:50)10 nm X140 nm BE-1/SH-1/X2 (30:65:5)5 nm SH-125 nm ETM-2:Liq (50:50)4 nm KF100 nm Al

TABLE-US-00005 Voltage LumEff EQE LT.sub.50 Example X1 X2 [V] [lm/W] [%] CIE.sub.x,y [%] Device Ir(DPBIC).sub.3 Ir(DPBIC).sub.3 4.0 23.4 14.0 0.18; 0.38 100 5.1.sup.1) Device IIa Ir(DPBIC).sub.3 3.9 30.9 18.3 0.18; 0.36 101 5.2 Device IIa IIa 4.0 30.5 18.4 0.18; 0.37 101 5.3 .sup.1)Comparative example

Device 6: Compound IIa as Electron/Exciton Blocking Layer and Compound IIa as Electron/Exciton Blocking Layer and as Co-Host

[0195] HIL Plexcore AJ20-100010 nm Ir(DPBIC).sub.3:MoO.sub.3 (50:50)10 nm X140 nm BE-12/SH-3/X2 (10:75:15)5 nm SH-325 nm ETM-2:Liq (50:50)4 nm KF100 nm Al

TABLE-US-00006 Voltage LumEff EQE LT.sub.50 Example X1 X2 [V] [lm/W] [%] CIE.sub.x,y [%] Device Ir(DPBIC).sub.3 Ir(DPBIC).sub.3 3.2 28.6 18.1 0.15; 0.26 100 6.1.sup.1) Device IIa Ir(DPBIC).sub.3 3.2 29.1 18.4 0.16; 0.27 124 6.2 Device IIa IIa 3.3 29.6 19.0 0.15; 0.27 114 6.3 .sup.1)Comparative example

Device 7: Compound of Formula IIa (Isomeric Mixture) as Electron/Exciton Blocking Layer and in the Hole Transport Layer

[0196] HIL Plexcore AJ20-100010 nm X1:MoO.sub.3 (50:50)10 nm X140 nm BE-1/SH-5/Ir(DPBIC).sub.3 (10:80:10)SH-525 nm ETM-2:Liq (50:50)4 nm KF100 nm Al

TABLE-US-00007 Voltage LumEff EQE LT.sub.50 Example X1 [V] [lm/W] [%] CIE.sub.x,y [%] Device Ir(DPBIC).sub.3 4.6 20.1 18.5 0.15; 0.26 100 7.1.sup.1) Device IIa (75:25).sup.2) 4.4 21.6 18.2 0.16; 0.26 168 7.2 .sup.1)Comparative example .sup.2)75% by weight IIa and 25% by weight IIa

Device 8: Compound of Formula IIa (Isomeric Mixture) as Electron/Exciton Blocking Layer and in the Hole Transport Layer

[0197] HIL Plexcore AJ20-100010 m X1:MoO.sub.3 (50:50)10 nm X160 nm BE-1/SH-4/Ir(DPBIC).sub.3 (10:85:5)SH-425 nm ETM-1:Liq (50:50)4 nm KF100 nm Al

TABLE-US-00008 Voltage LumEff EQE LT.sub.50 Example X1 [V] [lm/W] [%] CIE.sub.x,y [%] Device Ir(DPBIC).sub.3 6.8 10.9 14.5 0.16; 0.26 100 8.1.sup.1) Device IIa (75:25).sup.2) 6.3 13.4 17.1 0.16; 0.25 103 8.2 .sup.1)Comparative example .sup.2)75% by weight IIa and 25% by weight IIa

[0198] The application examples show that the inventive compounds can increase the device performance, such as lifetime and voltage. In particular the external quantum efficiency can be significantly increased, especially, when the inventive compounds are implemented in the exciton blocking layer.

[0199] Also, the inventive compounds can be used in a pure isomeric form or as mixture of cyclometalation isomers without significant impact on the device performance.

[0200] In the following, the compounds employed in the device examples mentioned above are shown. Said compounds are commercially available and/or prepared by processes known in the art and mentioned in the specification of the present application.

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