EP4402141A1

EP4402141A1 - Materials for organic electroluminescent devices

Info

Publication number: EP4402141A1
Application number: EP22786305.7A
Authority: EP
Inventors: Stefan Schramm; Ilona STENGEL; Amir Hossein PARHAM; Philipp SCHUETZ
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2021-09-13
Filing date: 2022-09-12
Publication date: 2024-07-24
Also published as: WO2023036976A1; KR20240058919A; CN117917983A

Abstract

The present invention relates to a heterocyclic compound of formula (1), which is substituted by at least one cyano group, as well as compositions and devices comprising these compounds, especially organic electroluminescent devices comprising these compounds as host materials.

Description

Materials for organic electroluminescent devices

The present invention describes heterocyclic derivatives substituted by at least one cyano group, as well as compositions and devices comprising these compounds, especially organic electroluminescent devices comprising these compounds as host materials.

In organic electroluminescent devices (OLEDs), phosphorescent organometallic complexes are often used as emitting materials. In general, there is still room for improvement in OLEDs, especially OLEDs that exhibit triplet emission (phosphorescence), for example in terms of efficiency, operating voltage and lifetime. The properties of phosphorescent OLEDs are not only determined by the triplet emitters used. Here, the other materials used, such as host materials or charge transport materials, are also of particular importance. Improvements in these materials can therefore also lead to improvements in the OLED properties.

There is also still room for improvement in OLEDs that exhibit singlet emission (fluorescence and/or thermally activated delayed fluorescence), also in terms of efficiency, operating voltage and lifetime. Here too, the properties of fluorescent OLEDs are also not only determined by the singlet emitters but also by the the other materials used, such as the host materials and the charge transport materials. Improvements in these materials can therefore also lead to improvements in the OLED properties.

An emitter compound here is taken to mean a compound which emits light during operation of the electronic device. A host compound in this case is taken to mean a compound which is present in the mixture in a greater proportion than the emitter compound. The term matrix compound and the term host compound can be used synonymously. The host compound preferably does not emit light. Even if a plurality of different host compounds are present in the mixture of the emitting layer, their individual proportions are typically greater than the proportion of the emitter compounds, or the proportions of the individual emitter compounds if a plurality of emitter compounds are present in the mixture of the emitting layer.

If a mixture of a plurality of compounds is present in the emitting layer, the emitter compound is typically the component present in smaller amount, i.e. in a smaller proportion than the other compounds present in the mixture of the emitting layer. In this case, the emitter compound is also referred to as dopant. Host materials for use in organic electronic devices are well known to the person skilled in the art. The term "matrix material" is also frequently used in the prior art when what is meant is a host material for phosphorescent emitters. This use of the term is also applicable to the present invention. In the meantime, a multitude of host materials has been developed both for fluorescent and for phosphorescent electronic devices.

According to the prior art, carbazole derivatives, indenocarbazole derivatives, indolocarbazole derivatives and azacarbazole derivatives are among the host materials used for phosphorescent emitters. Host compounds comprising azacarbazole and carbazole groups have been disclosed in the prior art (for example in JP2006120689). There is generally still a need for improvement in these materials for use as host materials. The problem addressed by the present invention is that of providing compounds which are especially suitable for use as host material in a phosphorescent or fluorescent OLEDs or as electron transport materials.

A further means of improving the performance data of electronic devices, especially of organic electroluminescent devices, is to use combinations of two or more materials, especially two or more host materials. US 6,392,250 B1 discloses, for example, the use of a mixture consisting of an electron transport material, a hole transport material and a fluorescent emitter in the emission layer of an OLED. US 6,803,720 B1 discloses the use of a mixture comprising a phosphorescent emitter and a hole transport material and an electron transport material in the emission layer of an OLED.

However, there is still need for improvement in the case of use of the host materials or in the case of use of mixtures of the host materials, especially in relation to efficiency, operating voltage and/or lifetime of the organic electronic device.

Surprisingly, it has been found that compounds and mixtures comprising the compounds described in more detail below solve this problem and are particularly suitable for use in OLEDs. In particular, the OLEDs have a long lifetime, a high efficiency and a low operating voltage. These compounds, the mixture comprising these compounds as well as electronic devices, in particular organic electroluminescent devices, containing these compounds are therefore the object of the present invention. The invention therefore provides a compound of the following formula (1): where the symbols and indices used are as follows:

Ar¹ is a group of formula (Ar1), where the dashed bond indicates the bonding position to the biphenyl group in formula (1); X is the same or different at each instance and is CR^X or N, or two groups X form a condensed ring together, and with the proviso that at least one X is N in the group of formula (Ar1);

Ar² is a group of formula (Ar2-A) or (Ar2-B): where the dashed bond indicates the bonding position to the biphenyl group in formula (1); and

Y is the same or different at each instance and is CR^Y or N; and two groups Y may form a condensed ring together,

R¹, R², R^x, R^Y stand on each occurrence, identically or differently, for a radical selected from H, D, F, Cl, Br, I, CHO, CN, C(=O)Ar, P(=O)(Ar)₂, S(=O)Ar, S(=O)₂Ar, N(R)₂, N(Ar)₂, NO₂, Si(R)₃, B(OR)₂, OSO₂R, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non-adjacent CH₂ groups may be replaced by RC=CR, C=C, Si(R)₂, Ge(R)₂, Sn(R)₂, C=O, C=S, C=Se, P(=O)(R), SO, SO₂, O, S or CONR and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R, and an aryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R; where two radicals R¹, two radicals R², two radicals R^x , two radicals R^y may form an aliphatic, aromatic or heteroaromatic ring system together, which may be substituted by one or more radicals R;

R stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CHO, CN, C(=O)Ar, P(=O)(Ar)₂, S(=O)Ar, S(=O)₂Ar, N(R')₂, N(Ar)₂, NO₂, Si(R')₃, B(OR')₂, OSO₂R', a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R', where in each case one or more non- adjacent CH₂ groups may be replaced by R'C=CR', C=C, Si(R')₂, Ge(R')₂, Sn(R')₂, C=O, C=S, C=Se, P(=O)(R'), SO, SO₂, O, S or CONR' and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R', or an aryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R'; where two radicals R may form an aliphatic or aromatic ring system together, which may be substituted by one or more radicals R'; Ar is, on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case also be substituted by one or more radicals R';

R' stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CN, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 20 C atoms or branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 C atoms, where in each case one or more non-adjacent CH2 groups may be replaced by SO, SO₂, O, S and where one or more H atoms may be replaced by D, F, Cl, Br or I, or an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms; and n is the same or different at each instance and is 0, 1 , 2 or 3; m is the same or different at each instance and is 0, 1 , 2, 3 or 4.

Furthermore, the following definitions of chemical groups apply for the purposes of the present application:

An aryl group in the sense of this invention contains 6 to 60 aromatic ring atoms, preferably 6 to 40 aromatic ring atoms, more preferably 6 to 20 aromatic ring atoms; a heteroaryl group in the sense of this invention contains 5 to 60 aromatic ring atoms, preferably 5 to 40 aromatic ring atoms, more preferably 5 to 20 aromatic ring atoms, at least one of which is a heteroatom. The heteroatoms are preferably selected from N, O and S. This represents the basic definition. If other preferences are indicated in the description of the present invention, for example with respect to the number of aromatic ring atoms or the heteroatoms present, these apply.

An aryl group or heteroaryl group here is taken to mean either a simple aromatic ring, i.e. benzene, or a simple heteroaromatic ring, for example pyridine, pyrimidine or thiophene, or a condensed (annellated) aromatic or heteroaromatic polycycle, for example naphthalene, phenanthrene, quinoline or carbazole. A condensed (annellated) aromatic or heteroaromatic polycycle in the sense of the present application consists of two or more simple aromatic or heteroaromatic rings condensed with one another. An aryl or heteroaryl group, which may in each case be substituted by the above-mentioned radicals and which may be linked to the aromatic or heteroaromatic ring system via any desired positions, is taken to mean, in particular, groups derived from benzene, naphthalene, anthracene, phenanthrene, pyrene, dihydropyrene, chrysene, perylene, fluoranthene, benz- anthracene, benzophenanthrene, tetracene, pentacene, benzopyrene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothiophene, dibenzo- thiophene, pyrrole, indole, isoindole, carbazole, pyridine, quinoline, isoquinoline, acridine, phenanthridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, pheno- thiazine, phenoxazine, pyrazole, indazole, imidazole, benzimidazole, naphthimidazole, phen- anthrimidazole, pyridimidazole, pyrazinimidazole, quinoxalinimidazole, oxazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, 1 ,2-thiazole, 1 ,3- thiazole, benzothiazole, pyridazine, benzopyridazine, pyrimidine, benzopyrimidine, quinoxaline, pyrazine, phenazine, naphthyridine, azacarbazole, benzocarboline, phenan- throline, 1 ,2,3-triazole, 1 ,2,4-triazole, benzotriazole, 1 ,2,3-oxadiazole, 1 ,2,4-oxadiazole, 1 ,2,5-oxadiazole, 1 ,3,4-oxadiazole, 1 ,2,3-thiadiazole, 1 ,2,4-thiadiazole, 1 ,2,5-thiadiazole,

1.3.4-thiadiazole, 1 ,3,5-triazine, 1 ,2,4-triazine, 1 ,2,3-triazine, tetrazole, 1 ,2,4,5-tetrazine,

1.2.3.4-tetrazine, 1 ,2,3,5-tetrazine, purine, pteridine, indolizine and benzothiadiazole.

An aryloxy group in accordance with the definition of the present invention is taken to mean an aryl group, as defined above, which is bonded via an oxygen atom. An analogous definition applies to heteroaryloxy groups.

An aromatic ring system in the sense of this invention contains 6 to 60 C atoms in the ring system, preferably 6 to 40 C atoms, more preferably 6 to 20 C atoms. A heteroaromatic ring system in the sense of this invention contains 5 to 60 aromatic ring atoms, preferably 5 to 40 aromatic ring atoms, more preferably 5 to 20 aromatic ring atoms, at least one of which is a heteroatom. The heteroatoms are preferably selected from N, O and/or S. An aromatic or heteroaromatic ring system in the sense of this invention is intended to be taken to mean a system which does not necessarily contain only aryl or heteroaryl groups, but instead in which, in addition, a plurality of aryl or heteroaryl groups may be connected by a non-aromatic unit (preferably less than 10% of the atoms other than H), such as, for example, an sp³- hybridised C, Si, N or O atom, an sp²-hybridised C or N atom or an sp-hybridised C atom. Thus, for example, systems such as 9,9'-spirobifluorene, 9,9'-diarylfluorene, triarylamine, diaryl ether, stilbene, etc., are also intended to be taken to be aromatic ring systems in the sense of this invention, as are systems in which two or more aryl groups are connected, for example, by a linear or cyclic alkyl, alkenyl or alkynyl group or by a silyl group. Furthermore, systems in which two or more aryl or heteroaryl groups are linked to one another via single bonds are also taken to be aromatic or heteroaromatic ring systems in the sense of this invention, such as, for example, systems such as biphenyl, terphenyl or diphenyltriazine.

An aromatic or heteroaromatic ring system having 5 - 60 aromatic ring atoms, which may in each case also be substituted by radicals as defined above and which may be linked to the aromatic or heteroaromatic group via any desired positions, is taken to mean, in particular, groups derived from benzene, naphthalene, anthracene, benzanthracene, phenanthrene, benzophenanthrene, pyrene, chrysene, perylene, fluoranthene, naphthacene, pentacene, benzopyrene, biphenyl, biphenylene, terphenyl, terphenylene, quaterphenyl, fluorene, spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- or trans- indenofluorene, truxene, isotruxene, spirotruxene, spiroisotruxene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothiophene, dibenzo- thiophene, pyrrole, indole, isoindole, carbazole, indolocarbazole, indenocarbazole, pyridine, quinoline, isoquinoline, acridine, phenanthridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, phenothiazine, phenoxazine, pyrazole, indazole, imidazole, benzimi- dazole, naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazinimidazole, quinoxalin- imidazole, oxazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxa- zole, 1 ,2-thiazole, 1 ,3-thiazole, benzothiazole, pyridazine, benzopyridazine, pyrimidine, benzopyrimidine, quinoxaline, 1 ,5-diazaanthracene, 2,7-diazapyrene, 2,3-diazapyrene, 1 ,6-diazapyrene, 1 ,8-diazapyrene, 4,5-diazapyrene, 4,5,9,10-tetraazaperylene, pyrazine, phenazine, phenoxazine, phenothiazine, fluorubin, naphthyridine, azacarbazole, benzo- carboline, phenanthroline, 1 ,2,3-triazole, 1 ,2,4-triazole, benzotriazole, 1 ,2,3-oxadiazole,

1.2.4-oxadiazole, 1 ,2,5-oxadiazole, 1 ,3,4-oxadiazole, 1 ,2,3-thiadiazole, 1 ,2,4-thiadiazole,

1.2.5-thiadiazole, 1 ,3,4-thiadiazole, 1 ,3,5-triazine, 1 ,2,4-triazine, 1 ,2,3-triazine, tetrazole,

1.2.4.5-tetrazine, 1 ,2,3,4-tetrazine, 1 ,2,3,5-tetrazine, purine, pteridine, indolizine and benzo- thiadiazole, or combinations of these groups.

For the purposes of the present invention, a straight-chain alkyl group having 1 to 40 C atoms or a branched or cyclic alkyl group having 3 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms, in which, in addition, individual H atoms or CH2 groups may be substituted by the groups mentioned above under the definition of the radicals, is preferably taken to mean the radicals methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl, cyclopentyl, neopentyl, n-hexyl, cyclohexyl, neohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoromethyl, pentafluoroethyl, 2,2,2- trifluoroethyl, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, ethynyl, propynyl, butynyl, pentynyl, hexynyl or octynyl. An alkoxy or thioalkyl group having 1 to 40 C atoms is preferably taken to mean methoxy, trifluoromethoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t- butoxy, n-pentoxy, s-pentoxy, 2-methylbutoxy, n-hexoxy, cyclohexyloxy, n-heptoxy, cyclo- heptyloxy, n-octyloxy, cyclooctyloxy, 2-ethylhexyloxy, pentafluoroethoxy, 2,2,2-tri- fluoroethoxy, methylthio, ethylthio, n-propylthio, i-propylthio, n-butylthio, i-butylthio, s-butylthio, t-butylthio, n-pentylthio, s-pentylthio, n-hexylthio, cyclohexylthio, n-heptylthio, cycloheptylthio, n-octylthio, cyclooctylthio, 2-ethylhexylthio, trifluoromethylthio, pentafluoro- ethylthio, 2,2,2-trifluoroethylthio, ethenylthio, propenylthio, butenylthio, pentenylthio, cyclo- pentenylthio, hexenylthio, cyclohexenylthio, heptenylthio, cycloheptenylthio, octenylthio, cyclooctenylthio, ethynylthio, propynylthio, butynylthio, pentynylthio, hexynylthio, heptynyl- thio or octynylthio.

The formulation that two radicals may form a ring with one another is, for the purposes of the present application, intended to be taken to mean, inter alia, that the two radicals are linked to one another by a chemical bond. This is illustrated by the following schemes:

Furthermore, however, the above-mentioned formulation is also intended to be taken to mean that, in the case where one of the two radicals represents hydrogen, the second radical is bonded at the position to which the hydrogen atom was bonded, with formation of a ring. This is illustrated by the following scheme:

When two radicals form a ring with one another, then it is preferred that the two radicals are adjacent radicals. Adjacent radicals in the sense of the present invention are radicals which are bonded to atoms which are linked directly to one another or which are bonded to the same atom.

In accordance with a preferred embodiment, the compound of formula (1) is selected from the compounds of formulae (1-1) to (1-6), where the symbols have the definition as above. In accordance with a very preferred embodiment, the compound of formula (1) is selected from the compounds of formulae (1-1-1) to (1-6-2),

where the symbols have the definition as above.

It is preferred that the group Ar¹ is selected from groups of formulae (Ar1-1) to (Ar1-14),

where the dashed bond indicates the bonding to the biphenyl group in formula (1) or formulae(1-1) to (1-5), where the symbol R^x has the definition as given in above and where: p is at each occurrence, independently, 0, 1 , 2, 3 or 4; q is at each occurrence, independently, 0, 1 , 2 or 3.

Among the formulae (Ar1-1) to (Ar1-14), the formulae (Ar1 -1), (Ar1-3) and (Ar1-5) are preferred and the formula (Ar1-1) is very preferred.

It is also preferred that the group Ar² is selected from groups of formulae (Ar2-A1) to (Ar2-

A15) and (Ar2-B1),

where the dashed bond indicates the bonding to the biphenyl group in formula (1), where the symbol R^Y has the definition as given above and where: s is at each occurrence, independently, 0, 1, 2, 3 or 4; t is at each occurrence, independently, 0, 1, 2 or 3.

Among the formulae (Ar2-A1) to (Ar2-A15) and (Ar2-B1), the formulae (Ar2-A1), (Ar2-A5), (Ar2-A7), (Ar2-B1) are preferred and the formulae (Ar2-A1) and (Ar2-B1) are very preferred.

Preferably, the group Ar¹ is a group of formula (Ar1-1) and the group Ar² is a group of formula (Ar2-A1) or (Ar2-B1).

Preferably, R¹, R², R^x, R^Y stand on each occurrence, identically or differently, for H, D, F, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40, preferably 1 to 20, more preferably 1 to 10 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 40, preferably 3 to 20, more preferably 3 to 10 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non-adjacent CH₂ groups may be replaced by RC=CR, C=C, O or S and where one or more H atoms may be replaced by D or F, an aromatic or heteroaromatic ring system having 5 to 60, preferably 5 to 40, more preferably 5 to 30, particularly preferably 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R. More preferably, R¹, R², R^x, R^Y stand on each occurrence, identically or differently, for H, D, F, a straight-chain alkyl group having 1 to 20, preferably 1 to 10, more preferably 1 to 6 C atoms or branched or a cyclic alkyl group having 3 to 20, preferably 3 to 10, more preferably 3 to 6 C atoms, each of which may be substituted by one or more radicals R, an aromatic or heteroaromatic ring system having 5 to 40, preferably 5 to 30, more preferably 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R.

Particularly preferably, R¹, R², R^x, R^Y stand on each occurrence, identically or differently, for H, D, a straight-chain alkyl group having 1 to 10, preferably 1 to 6 C atoms or branched or a cyclic alkyl group having 3 to 10, preferably 3 to 6 C atoms, each of which may be substituted by one or more radicals R, or an aromatic or heteroaromatic ring system having 5 to 18 aromatic ring atoms, preferably 6 to 12 aromatic ring atoms, which may in each case be substituted by one or more radicals R.

Very particularly preferably, R¹, R², R^x, R^Y stand for H or D.

The following compounds are examples of compound of formula (1):

The present invention furthermore provides a composition comprising a material selected from compounds of the formula (1) as defined above and a material selected from hole- transporting host materials.

Preferably, the second host material in the composition is selected from hole-transporting host materials selected from the group of the carbazole and triarylamine derivatives, more particularly the biscarbazoles, the bridged carbazoles, the triarylamines, the dibenzofuran- carbazole derivatives or dibenzofuran-amine derivatives, and the carbazoleamines.

In accordance with a preferred embodiment, the second host material is selected from hole- transporting host materials selected from compounds of formula (h-1) or (h-2),

where:

K is Ar⁴ or -L²-N(Ar)₂;

Z is C-R^z or C-R^A; or two adjacent groups Z form a condensed ring together;

R_A is -L³-Ar⁵ or -L¹-N(Ar)₂;

R^z is the same or different at each instance and is selected from H, D, F, Cl, Br, I, N(Ar)₂, N(R)₂, OAr, SAr, CN, NO₂, OR, SR, COOR, C(=O)N(R)₂, Si(R)₃, B(OR)₂, C(=O)R, P(=O)(R)₂, S(=O)R, S(=O)₂R, OSO₂R, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R radicals, where one or more nonadjacent CH₂ groups may be replaced by Si(R)₂, C=O, NR, O, S or CONR, or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms, preferably 5 to 40 aromatic ring atoms, and may be substituted in each case by one or more R radicals;

L¹, L² are the same or different at each instance and are a single bond or an aromatic or heteroaromatic ring system which has 5 to 30 aromatic ring atoms and may be substituted by one or more R radicals;

L³ is a single bond or an aromatic or heteroaromatic ring system which has 5 to 30 aromatic ring atoms and may be substituted by one or more R radicals, where one radical R on L³ may form a ring with a radical R^z on the carbazole; Ar⁴ is an aromatic ring system having 6 to 40 aromatic ring atoms or a heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may be substituted by one or more R radicals;

Ar⁵ is the same or different at each instance and is an unsubstituted or substituted heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may be substituted by one or more R;

R^z is the same or different at each instance and is H, D, F, Cl, Br, I, N(Ar)₂, N(R)₂, OAr, SAr, CN, NO₂, OR, SR, COOR, C(=O)N(R)₂, Si(R)₃, B(OR)₂, C(=O)R, P(=O)(R)₂, S(=O)R, S(=O)₂R, OSO₂R, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R radicals, where one or more nonadjacent CH₂ groups may be replaced by Si(R)₂, C=O, NR, O, S or CONR, or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms, preferably 5 to 40 aromatic ring atoms, and may be substituted in each case by one or more R radicals; at the same time, two R^z radicals together may also form a ring system;

E is on each occurrence, independently, a single bond or a group C(R⁰)₂;

R⁰ is selected on each occurrence, independently, from a straight-chain alkyl group having 1 to 10 carbon atoms or a branched or cyclic alkyl group having 3 to 10 carbon atoms, which may in each case be substituted by one or more R' radicals; x, y are selected, independently, from 0 or 1 , wherein when x or y is 0, then the corresponding group E is absent; and x + y = 1 or 2; with the proviso that the compounds of formulae (h-1) and (h-2) comprise at least one group Z, which stands for R^A; and where R, R' and Ar have the same definition as above.

Preferably, L¹, L² are the same or different at each instance and are a single bond or an aromatic or heteroaromatic ring system which has 5 to 25, more preferably 5 to 20, even more preferably 6 to 18 aromatic ring atoms and may be substituted by one or more R radicals.

Preferably, L³ is a single bond or an aromatic or heteroaromatic ring system which has 5 to 25, aromatic ring atoms, more preferably 5 to 20, even more preferably 6 to 18 aromatic ring atoms and may be substituted by one or more R radicals, where one radical R on L³ may form a ring with a radical R^z on the carbazole;

Preferably, the group Ar⁵ is a an unsubstituted or substituted heteroaromatic ring system selected from the groups of formulae (Ar5-1) to (Ar5-6), where the dashed bond indicates the bonding to L³ or Z;

V is C-R^V, with the proviso that V stands for C when it is bonded to the group of formula (h-1) or (h-2); or two adjacent groups V form a condensed ring together;

T is C-R^T, with the proviso that T stands for C when it is bonded to the group of formula (h-1) or (h-2), or two adjacent groups T form a condensed ring together;

M is an aromatic ring system having 6 to 40 aromatic ring atoms or a heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may be substituted by one or more R radicals;

E¹ is on each occurrence, independently, a single bond or a group C(R⁰)₂; where R⁰ has the same meaning as above;

R^T, R^V is the same or different at each instance and is selected from H, D, F, Cl, Br, I, N(Ar)₂, N(R)₂, OAr, SAr, CN, NO₂, OR, SR, COOR, C(=O)N(R)₂, Si(R)₃, B(OR)₂, C(=O)R, P(=O)(R)₂, S(=O)R, S(=O)₂R, OSO₂R, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R radicals, where one or more nonadjacent CH₂ groups may be replaced by Si(R)₂, C=O, NR, O, S or CONR, or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms, preferably 5 to 40 aromatic ring atoms, and may be substituted in each case by one or more R radicals; at the same time, two R^T radicals together may form a ring system and two R^V radicals together may form a ring system; x¹, y¹ are selected, independently, from 0 or 1 , wherein when x¹ or y¹ is 0, then the corresponding group E¹ is absent; with the proviso that x¹ + y¹ = 1 or 2; and where R and Ar have the same definition as above.

In accordance, with a very preferred embodiment, the second host material is selected from hole-transporting host materials selected from compounds of formula (h-1-1) to (h-1-3) and (h-2-1) to (h-2-2),

where the symbols and the indices x, y, x¹ and y¹ have the same meaning as above, and where the other indices have the following meaning: c, f stands, independently, for 0, 1, 2, 3 or 4; d, e stands, independently, for 0, 1, 2 or 3; g stands for 0, 1, 2 or 3 if x¹=0; or for 0, 1 or 2 if x¹=1; h stands for 0, 1, 2, 3 or 4 if y¹=0; or for 0, 1, 2 or 3 if y¹=1; k stands for 0, 1, 2, 3 or 4 if x=0; or for 0, 1, 2 or 3 if x=1; and

I stands for 0, 1, 2 or 3 if y=0; or for 0, 1 or 2 if y=1.

Example of hole-transporting host materials suitable as second host material in the composition are depicted in the table below:

Preferably, the composition comprises a first host material selected from compounds of the formula (1) as defined above, a second host material selected from hole-transporting host materials and a third compound selected from phosphorescent emitters, fluorescent emitters and emitters that exhibit TADF (thermally activated delayed fluorescence).

In accordance with a preferred embodiment, the third compound is selected from phosphorescent emitters. Phosphorescence in the context of this invention is understood to mean luminescence from an excited state having higher spin multiplicity, i.e. a spin state > 1 , especially from an excited triplet state. In the context of this application, all luminescent complexes with transition metals or lanthanides, especially all iridium, platinum and copper complexes, shall be regarded as phosphorescent emitters.

Examples of the emitters described above can be found in applications WO 00/70655, WO 2001/41512, WO 2002/02714, WO 2002/15645, EP 1191613, EP 1191612, EP 1191614, WO 05/033244, WO 05/019373, US 2005/0258742, WO 2009/146770, WO 2010/015307, WO 2010/031485, WO 2010/054731, WO 2010/054728, WO 2010/086089, WO 2010/099852, WO 2010/102709, WO 2011/032626, WO 2011/066898, WO 2011/157339, WO 2012/007086, WO 2014/008982, WO 2014/023377, WO 2014/094961, WO 2014/094960, WO 2015/036074, WO 2015/104045, WO 2015/117718, WO 2016/015815, WO 2016/124304, WO 2017/032439, WO 2018/011186 and WO 2018/041769, WO 2019/020538, WO 2018/178001, WO 2019/115423 or WO 2019/158453. In general, all phosphorescent complexes as used for phosphorescent OLEDs according to the prior art and as known to those skilled in the art in the field of organic electroluminescence are suitable, and the person skilled in the art will be able to use further phosphorescent complexes without exercising inventive skill. Examples of phosphorescent dopants are depicted below:

In accordance with another preferred embodiment, the third compound is selected from emitters which exhibit thermally activated delayed fluorescence (TADF emitters) (e.g. H. Uoyama et al., Nature 2012, vol. 492, 234). These emitters are organic materials in which the energy gap between the lowest triplet state T₁ and the first excited singlet state S₁ is sufficiently small that the S₁ state is thermally accessible from the T₁ state. The TADF emitter is preferably an aromatic compound having both donor and acceptor substituents, with only slight spatial overlap between the LIIMO and the HOMO of the compound. What is understood by donor and acceptor substituents is known in principle to those skilled in the art. Suitable donor substituents are especially diaryl- or -heteroarylamino groups and carbazole groups or carbazole derivatives, each preferably bonded to the aromatic compound via N. These groups may also have further substitution. Suitable acceptor substituents are especially cyano groups, but also, for example, electron-deficient heteroaryl groups which may also have further substitution, for example substituted or unsubstituted triazine groups.

The general art knowledge of the person skilled in the art includes knowledge of which materials are generally suitable as TADF compounds. The following references disclose, by way of example, materials that are potentially suitable as TADF compounds: - Tanaka et al., Chemistry of Materials 25(18), 3766 (2013). - Lee et al., Journal of Materials Chemistry C 1(30), 4599 (2013). - Zhang et al., Nature Photonics advance online publication, 1 (2014), doi: 10.1038/nphoton.2014.12. - Serevicius et al., Physical Chemistry Chemical Physics 15(38), 15850 (2013). - Li et al., Advanced Materials 25(24), 3319 (2013).

- Youn Lee et al., Applied Physics Letters 101(9), 093306 (2012). - Nishimoto et al., Materials Horizons 1, 264 (2014), doi: 10.1039/C3MH00079F. - Valchanov et al., Organic Electronics, 14(11), 2727 (2013). - Nasu et al., ChemComm, 49, 10385 (2013).

In addition, the following patent applications disclose potential TADF compounds: WO 2013/154064, WO 2013/133359, WO 2013/161437, WO 2013/081088, WO 2013/081088, WO 2013/011954, JP 2013/116975 und US 2012/0241732.

In addition, the person skilled in the art is able to infer design principles for TADF compounds from these publications. For example, Valchanov et al. show how the color of TADF compounds can be adjusted.

Examples of suitable molecules which exhibit TADF are the structures shown in the following table:

Still in accordance with another preferred embodiment, the third compound is selected from fluorescent emitters. Preferred fluorescent emitters are aromatic anthracenamines, aro- matic anthracenediamines, aromatic pyrenamines, aromatic pyrenediamines, aromatic chrysenamines or aromatic chrysenediamines. An aromatic anthracenamine is taken to mean a compound in which one diarylamino group is bonded directly to an anthracene group, preferably in the 9-position. An aromatic anthracenediamine is taken to mean a com- pound in which two diarylamino groups are bonded directly to an anthracene group, preferably in the 9,10-position. Aromatic pyrenamines, pyrenediamines, chrysenamines and chrysenediamines are defined analogously thereto, where the diarylamino groups are preferably bonded to the pyrene in the 1 -position or in the 1,6-position. Further preferred emitters are indenofluorenamines or indenofluorenediamines, for example in accordance with WO 2006/108497 or WO 2006/122630, benzoindenofluorenamines or benzoindenofluorenediamines, for example in accordance with WO 2008/006449, and dibenzoindenofluorenamines or dibenzoindenofluorenediamines, for example in accordance with WO 2007/140847, and the indenofluorene derivatives containing con- densed aryl groups which are disclosed in WO 2010/012328. Still further preferred emitters are benzanthracene derivatives as disclosed in WO 2015/158409, anthracene derivatives as disclosed in WO 2017/036573, fluorene dimers connected via heteroaryl groups like in WO 2016/150544 or phenoxazine derivatives as disclosed in WO 2017/028940 and WO 2017/028941. Preference is likewise given to the pyrenarylamines disclosed in WO 2012/048780 and WO 2013/185871. Preference is likewise given to the benzoindenofluorenamines disclosed in WO 2014/037077, the benzofluorenamines disclosed in WO 2014/106522 and the indenofluorenes disclosed in WO 2014/111269 or WO 2017/036574, WO 2018/007421. Also preferred are the emitters comprising dibenzofuran or indenodibenzofuran moieties as disclosed in WO 2018/095888, WO 2018/095940, WO 2019/076789, WO 2019/170572 as well as in WO 2020/043657, WO 2020/043646 and WO/2020/043640. Preference is likewise given to boron derivatives as disclosed, for example, in WO 2015/102118, CN108409769, CN107266484, WO2017195669, US2018069182 as well as in WO 2020/208051 , W02021/058406, and WO 2021/094269.

In accordance with another preferred embodiment, the composition comprises a first host material selected from compounds of the formula (1) as defined above, a second host material selected from hole-transporting host materials, a third compound selected from phosphorescent emitters and emitters that exhibit TADF (thermally activated delayed fluorescence) and a fourth compound selected from phosphorescent emitters and fluorescent emitters.

Particularly preferred examples of such compositions are compositions comprising: - a first host material selected from compounds of the formula (1) as defined above, a second host material selected from hole-transporting host materials, a third compound selected from phosphorescent emitters and a fourth compound selected from phosphorescent emitters, wherein the third and fourth compound are selected differently; - a first host material selected from compounds of the formula (1) as defined above, a second host material selected from hole-transporting host materials, a third compound selected from phosphorescent emitters and a fourth compound selected from fluorescent emitters; - a first host material selected from compounds of the formula (1) as defined above, a second host material selected from hole-transporting host materials, a third compound selected from emitters that exhibit TADF (thermally activated delayed fluorescence) and a fourth compound selected from fluorescent emitters; where preferred host materials, phosphorescent emitters, TADF emitters and fluorescent emitters are as described above.

The compositions may also comprise further organic or inorganic compounds which are likewise used in the electronic device like, for example, further emitters or further host materials.

The compound of formula (1) or the composition comprising a comnpound of formula (1) may be processed by vapour deposition or from solution. If the compositions are applied from solution, formulations of the composition of the invention comprising at least one further solvent are required. These formulations may, for example, be solutions, dispersions or emulsions. For this purpose, it may be preferable to use mixtures of two or more solvents.

The present invention therefore further provides a formulation comprising a compounds of formula (1) or a composition comprising a compound of formula (1) and at least one solvent.

Suitable and preferred solvents are, for example, toluene, anisole, o-, m- or p-xylene, methyl benzoate, mesitylene, tetralin, veratrole, THF, methyl-THF, THP, chlorobenzene, dioxane, phenoxytoluene, especially 3-phenoxytoluene, (-)-fenchone, 1 , 2,3,5- tetramethylbenzene, 1 ,2,4,5-tetramethylbenzene, 1 -methylnaphthalene, 2- methylbenzothiazole, 2-phenoxyethanol, 2-pyrrolidinone, 3-methylanisole, 4-methylanisole,

3.4-dimethylanisole, 3,5-dimethylanisole, acetophenone, a-terpineol, benzothiazole, butyl benzoate, cumene, cyclohexanol, cyclohexanone, cyclohexylbenzene, decalin, dodecylbenzene, ethyl benzoate, indane, methyl benzoate, NMP, p-cymene, phenetole,

1.4-diisopropylbenzene, dibenzyl ether, diethylene glycol butyl methyl ether, triethylene glycol butyl methyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, diethylene glycol monobutyl ether, tripropylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 2-isopropylnaphthalene, pentylbenzene, hexylbenzene, heptylbenzene, octylbenzene, 1,1-bis(3,4-dimethylphenyl)ethane, hexamethylindane or mixtures of these solvents.

The present invention also provides for the use of the compound of formula (1) or of compositions comprising the compound of formula (1) in an organic electronic device, preferably in an emitting layer and/or in an electron-transporting layer.

The organic electronic device is preferably selected from organic integrated circuits (OlCs), organic field-effect transistors (OFETs), organic thin-film transistors (OTFTs), organic electroluminescent devices, organic solar cells (OSCs), organic optical detectors and organic photoreceptors, particular preference being given to organic electroluminescent devices.

Very particularly preferred organic electroluminescent devices containing at least one compound of the formula (1), as described above or described as preferred, are organic light-emitting transistors (OLETs), organic field-quench devices (OFQDs), organic light- emitting electrochemical cells (OLECs, LECs, LEECs), organic laser diodes (O-lasers) and organic light-emitting diodes (OLEDs); OLECs and OLEDs are especially preferred and OLEDs are the most preferred.

Preferably, the compound of formula (1) as described above or described as preferred is used in a layer having an electron-transporting function in an electronic device. The layer is preferably an electron injection layer (EIL), an electron transport layer (ETL), a hole blocker layer (HBL) and/or an emission layer (EML), more preferably an ETL, EIL and/or an EML. Most preferably, the compound of formula (1) or the composition is used in an EML as an electron-transporting host material in combination with a hole-transporting host material.

Therefore, the present invention further provides an organic electronic device which is especially selected from one of the aforementioned electronic devices and which comprises the compound of formula (1) or compositions comprising the compound of formula (1), as described above or described as preferred, preferably in an emission layer (EML), in an electron transport layer (ETL), in an electron injection layer (EIL) and/or in a hole blocker layer (HBL), very preferably in an EML, EIL and/or ETL and most preferably in an EML. In a particularly preferred embodiment of the present invention, the electronic device is an organic electroluminescent device, most preferably an organic light-emitting diode (OLED), containing the compound of formula (1) or a composition comprising the compound of formula (1) in the emission layer (EML).

In a particularly preferred embodiment of the present invention, the organic electroluminescent device is therefore one comprising an anode, a cathode and at least one organic layer comprising at least one light-emitting layer, wherein the at least one light- emitting layer contains at least one compound of the formula (1) or a composition comprising a compound of formula (1) as described above.

The light-emitting layer in the device of the invention, as described above, contains preferably between 99.9% and 1% by volume, further preferably between 99% and 10% by volume, especially preferably between 98% and 60% by volume, very especially preferably between 97% and 80% by volume, of host material composed of at least one compound of the formula (1) or composed of at least one a first host material selected from compounds of the formula (1) and a second host material selected from hole-transporting host materials as described above, based on the overall composition of emitter and host material.

Correspondingly, the light-emitting layer in the device of the invention preferably contains between 0.1% and 99% by volume, further preferably between 1% and 90% by volume, more preferably between 2% and 40% by volume, most preferably between 3% and 20% by volume, of the emitter based on the overall composition of the light-emitting layer composed of emitter and host material. If the compounds are processed from solution, preference is given to using the corresponding amounts in % by weight rather than the above-specified amounts in % by volume.

The light-emitting layer in the device of the invention, as described above, preferably contains the host material of the formula (1), preferably in combination with a host material selected from hole-transporting host materials, in a percentage by volume ratio between 3:1 and 1 :3, preferably between 1 :2.5 and 1 :1, more preferably between 1 :2 and 1:1. If the compounds are processed from solution, preference is given to using the corresponding ratio in % by weight rather than the above-specified ratio in % by volume. Apart from the cathode, anode and the layer comprising the composition of the invention, an electronic device may comprise further layers. These are selected, for example, from in each case one or more hole injection layers, hole transport layers, hole blocker layers, light- emitting layers, electron transport layers, electron injection layers, electron blocker layers, exciton blocker layers, interlayers, charge generation layers (IDMC 2003, Taiwan; Session 21 OLED (5), T. Matsumoto, T. Nakada, J. Endo, K. Mori, N. Kawamura, A. Yokoi, J. Kido, Multiphoton Organic EL Device Having Charge Generation Layer) and/or organic or inorganic p/n junctions. However, it should be pointed out that not necessarily every one of these layers need be present.

The sequence of layers in an organic electroluminescent device is preferably as follows: anode / hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode.

The sequence of the layers is a preferred sequence.

At the same time, it should be pointed out again that not all the layers mentioned need be present and/or that further layers may additionally be present.

An organic electroluminescent device of the invention may contain two or more light- emitting layers. According to the invention, at least one of the light-emitting layers contains at least one compound of the formula (1) and compositions comprising a compound of formula (1) as described above. More preferably, these emission layers in this case have several emission maxima between 380 nm and 750 nm overall, such that the overall result is white emission; in other words, various emitting compounds which may fluoresce or phosphoresce and which emit blue or yellow or orange or red light are used in the light- emitting layers. Especially preferred are three-layer systems, i.e. systems having three light-emitting layers, where the three layers show blue, green and orange or red emission (for the basic construction see, for example, WO 2005/011013). It should be noted that, for the production of white light, rather than a plurality of colour-emitting emitter compounds, an emitter compound used individually which emits over a broad wavelength range may also be suitable.

Suitable charge transport materials as usable in the hole injection or hole transport layer or electron blocker layer or in the electron transport layer of the organic electroluminescent device of the invention are, for example, the compounds disclosed in Y. Shirota et al., Chem. Rev. 2007, 107(4), 953-1010, or other materials as used in these layers according to the prior art.

Materials used for the electron transport layer may be any materials as used according to the prior art as electron transport materials in the electron transport layer. Especially suitable are aluminium complexes, for example Alq₃, zirconium complexes, for example Zrq4, benzimidazole derivatives, triazine derivatives, pyrimidine derivatives, pyridine derivatives, pyrazine derivatives, quinoxaline derivatives, quinoline derivatives, oxadiazole derivatives, aromatic ketones, lactams, boranes, diazaphosphole derivatives and phosphine oxide derivatives. Further suitable materials are derivatives of the abovementioned compounds as disclosed in JP 2000/053957, WO 2003/060956, WO 2004/028217, WO 2004/080975 and WO 2010/072300.

Preferred hole transport materials are especially materials which can be used in a hole transport, hole injection or electron blocker layer, such as indenofluoreneamine derivatives (for example according to WO 06/122630 or WO 06/100896), the amine derivatives disclosed in EP 1661888, hexaazatriphenylene derivatives (for example according to WO 01/049806), amine derivatives having fused aromatic systems (for example according to US 5,061,569), the amine derivatives disclosed in WO 95/09147, monobenzoindenofluoreneamines (for example according to WO 08/006449), dibenzoindenofluoreneamines (for example according to WO 07/140847), spirobifluoreneamines (for example according to WO 2012/034627 or the as yet unpublished EP 12000929.5), fluoreneamines (for example according to WO 2014/015937, WO 2014/015938 and WO 2014/015935), spirodibenzopyranamines (for example according to WO 2013/083216) and dihydroacridine derivatives (for example WO 2012/150001).

Preferred cathodes of electronic devices are metals having a low work function, metal alloys or multilayer structures composed of various metals, for example alkaline earth metals, alkali metals, main group metals or lanthanoids (e.g. Ca, Ba, Mg, Al, In, Mg, Yb, Sm, etc.). Additionally suitable are alloys composed of an alkali metal or alkaline earth metal and silver, for example an alloy composed of magnesium and silver. In the case of multilayer structures, in addition to the metals mentioned, it is also possible to use further metals having a relatively high work function, for example Ag or Al, in which case combinations of the metals such as Ca/Ag, Mg/Ag or Ba/Ag, for example, are generally used. It may also be preferable to introduce a thin interlayer of a material having a high dielectric constant between a metallic cathode and the organic semiconductor. Examples of useful materials for this purpose are alkali metal or alkaline earth metal fluorides, but also the corresponding oxides or carbonates (e.g. Li F, Li₂O, BaF₂, MgO, NaF, CsF, CS₂CO₃, etc.). It is also possible to use lithium quinolinate (LiQ) for this purpose. The layer thickness of this layer is preferably between 0.5 and 5 nm.

Preferred anodes are materials having a high work function. Preferably, the anode has a work function of greater than 4.5 eV versus vacuum. Firstly, metals having a high redox potential are suitable for this purpose, for example Ag, Pt or Au. Secondly, metal/metal oxide electrodes (e.g. Al/N i/N iO_x, AI/PtO_x) may also be preferred. For some applications, at least one of the electrodes has to be transparent or partly transparent in order to enable either the irradiation of the organic material (organic solar cell) or the emission of light (OLED, O-LA SER). Preferred anode materials here are conductive mixed metal oxides. Particular preference is given to indium tin oxide (ITO) or indium zinc oxide (IZO). Preference is further given to conductive doped organic materials, especially conductive doped polymers. In addition, the anode may also consist of two or more layers, for example of an inner layer of ITO and an outer layer of a metal oxide, preferably tungsten oxide, molybdenum oxide or vanadium oxide.

The organic electronic device, in the course of production, is appropriately (according to the application) structured, contact-connected and finally sealed, since the lifetime of the devices of the invention is shortened in the presence of water and/or air.

In a further preferred embodiment, the organic electronic device comprising the composition of the invention is characterized in that one or more organic layers comprising the composition of the invention are coated by a sublimation method. In this case, the materials are applied by vapour deposition in vacuum sublimation systems at an initial pressure of less than 10^-5 mbar, preferably less than 10^-6 mbar. In this case, however, it is also possible that the initial pressure is even lower, for example less than 10^-7 mbar. Preference is likewise given to an organic electroluminescent device, characterized in that one or more layers are coated by the OVPD (organic vapour phase deposition) method or with the aid of a carrier gas sublimation. In this case, the materials are applied at a pressure between 10^-5 mbar and 1 bar. A special case of this method is the OVJP (organic vapour jet printing) method, in which the materials are applied directly by a nozzle and thus structured (for example, M. S. Arnold et al., Appl. Phys. Lett. 2008, 92, 053301).

Preference is additionally given to an organic electroluminescent device, characterized in that one or more organic layers comprising the composition of the invention are produced from solution, for example by spin-coating, or by any printing method, for example screen printing, flexographic printing, nozzle printing or offset printing, but more preferably LITI (light-induced thermal imaging, thermal transfer printing) or inkjet printing. For this purpose, soluble compounds of the components of the composition of the invention are needed. High solubility can be achieved by suitable substitution of the corresponding compounds.

Processing from solution has the advantage that the layer comprising the composition of the invention can be applied in a very simple and inexpensive manner. This technique is especially suitable for the mass production of organic electronic devices.

In addition, hybrid methods are possible, in which, for example, one or more layers are applied from solution and one or more further layers are applied by vapour deposition.

These methods are known in general terms to those skilled in the art and can be applied to organic electroluminescent devices.

The invention therefore further provides a process for producing an organic electronic device comprising a composition of the invention as described above or described as preferred, characterized in that at least one organic layer comprising a composition of the invention is applied by gas phase deposition, especially by a sublimation method and/or by an OVPD (organic vapour phase deposition) method and/or with the aid of carrier gas sublimation, or from solution, especially by spin-coating or by a printing method.

In the production of an organic electronic device by means of gas phase deposition, there are two methods in principle by which an organic layer which is to comprise the composition of the invention and which may comprise multiple different constituents can be applied, or applied by vapour deposition, to any substrate. Firstly, the materials used can each be initially charged in a material source and ultimately evaporated from the different material sources ("co-evaporation"). Secondly, the various materials can be premixed (premix systems) and the mixture can be initially charged in a single material source from which it is ultimately evaporated ("premix evaporation"). In this way, it is possible in a simple and rapid manner to achieve the vapour deposition of a layer with homogeneous distribution of the components without a need for precise actuation of a multitude of material sources.

The invention accordingly further provides a process characterized in that the at least one compound of the formula (1) as described above or described as preferred and the compositions comprising the compound of formula (1) as described above or described as preferred are deposited from the gas phase successively or simultaneously from at least two material sources, optionally with other materials as described above or described as preferred, and form the organic layer.

The invention accordingly further provides a process characterized in that the composition of the invention as described above or described as preferred is utilized as material source for the gas phase deposition of the host system and, optionally together with further materials, forms the organic layer.

The invention further provides a process for producing an organic electronic device comprising a composition of the invention as described above or described as preferred, characterized in that the formulation of the invention as described above is used to apply the organic layer.

It should be pointed out that variations of the embodiments described in the present invention are covered by the scope of this invention. Any feature disclosed in the present invention may, unless this is explicitly ruled out, be exchanged for alternative features which serve the same purpose or an equivalent or similar purpose. Any feature disclosed in the present invention, unless stated otherwise, should therefore be considered as an example from a generic series or as an equivalent or similar feature.

All features of the present invention may be combined with one another in any manner, unless particular features and/or steps are mutually exclusive. This is especially true of preferred features of the present invention. Equally, features of non-essential combinations may be used separately (and not in combination).

The technical teaching disclosed with the present invention may be abstracted and combined with other examples. The invention is illustrated in more detail by the examples which follow, without any intention of restricting it thereby.

Synthesis examples

Synthesis Scheme:

Synthesis of 3-Bromo-5-gamma-carbolino-benzonitrile

A 1000mL three-neck flask is flushed three times with vacuum and nitrogen. To this flask, 3.56 g (0.148 mol, 2.0 eq.) of 60% NaH (suspension in paraffin oil) under Nitrogen atmosphere and 100 mL of dry DMF are added. The reaction mixture is cooled to 0-5°C using ice-bath, then a solution of 12.5 g (1.0eq. 0.074 mol) of 5H-Pyrido[4,3-b]indole in 150 mL dry DMF at 0-5°C is added. The reaction mixture is left to stir for 30 min at 0-5°C. Then, a solution of 15.6 g (1.05eq, 0.078 mol) of 3-Bromo-5-fluorobenzonitrile in 120 mL dry DMF is added at 0-5°C. The reaction mixture is continued to stir at 150°C overnight. For the workup the reaction mixture is taken up in water (300 mL) and aq. sat. NH4CI (70 mL) in a separate round bottom flask, cooled to 5-10 °C, added the reaction mass drop- wise through a dropping funnel. The product precipitates and is filtered and washed with water (100mL).

For further purification the crude product is dissolved in 100 mL of 2-propanol at 90 °C/1h Then it is cooled to 25 °C. The product is filtered, washed with ~15 mL of 2-propanol and dried under vacuum. Further purification can be achieved via column chromatography in Cyclohexane / Ethyl acetate.

Via this 14.3 g of pure (uHPLC > 95%) Product is achieved resulting in a yield of 55%. The following compounds can be synthesized in an analogous way: Synthesis of Gamma Carboline e-Host

In a dry 500 ml flask, 13,6g (39.058 mmol, 1 eq) of 3-Bromo-5-gamma-carbolino- benzonitrile, 17.3g (46.87 mmol, 1.2 eq) of 9-[3-(4,4,5,5-Tetramethyl-1 ,3,2-dioxaborolan-2- yl)phenyl] carbazole and 1.35g (1.172 mmol, 0.03 eq) Pd(PPh3)4 are suspended in 196 mL of a mixture of toluene:dioxane (4:1). This suspension is degassed by bubbling with nitrogen for 15 min. To this, 39 mL (2 eq) of 2M aq. Na2CO3 (degassed using nitrogen for 15 min) is added. Then the reaction mixture is evacuated and filled with nitrogen 2 times. The reaction is stirred at 80 °C overnight. For workup the reaction mixture is diluted with Toluene (200mL), filtered through celite, washed the celite with toluene (150mL), checked the celite for the absence of product, separated the water layer from toluene. Then, the aqueous layer is washed with toluene until product is absent in the aqueous layer. Finally, the toluene layer is evaporated.

For purification to the crude product Acetonitrile (100mL) is added and heated to 85 °C (bath temperature) for 1h. After this the reaction mixture is cooled to 10 °C and the precipitated product is filtered and washed with Acetonitrile (30 mL). Finally, the product is recrystallized in ethanol (100ml) by heating to 80 °C for 1 h. After this it is allowed to cool to 25 °C, then cooled to 10 °C. The obtained solid is filtered, washed with ethanol (2 x 10 mL) and dried under vacuum.

Via this 13.8 g of pure (uHPLC > 95%) Product is achieved resulting in a yield of 69%.

The following compounds can be synthesized in an analogous way:

Synthesis Example of Alpha-Carboline-Ortho-BIMBIM Host:

Synthesis of 3-Bromo-5-alpha-carbolino-benzonitrile

A 1000mL three-neck flask was flushed three times with vacuum and nitrogen. To this flask, 3.56 g (0.148 mol, 2.0 eq.) of 60% NaH (suspension in paraffin oil) under nitrogen atmosphere and 100 mL of dry DMF were added. The reaction mixture was cooled to 0 - 5°C using an ice-bath. Then a solution of 12.4 g (1.0eq. 0.074 mol) of alpha-Carboline in 150 mL dry DMF at 0 - 5°C was added. The reaction mixture was left to stir for 30 min at 0 - 5°C. After this, a solution of 15.6 g (1.05eq, 0.078 mol) of 3-Bromo-5-fluorobenzonitrile in 120 mL dry DMF was added at 0 - 5°C. The reaction mixture was continued to stir at 150°C overnight.

For the workup the reaction mixture was taken up in water (300 mL) and aq. sat. NH₄CI (70 mL) in a separate round bottom flask, cooled to 5 - 10 °C. The product precipitated and was filtered and washed with water (100mL).

For further purification the crude product was dissolved in 100 mL of 2-propanol at 90°C for 1h. Then it was cooled to 25°C. The product was filtered, washed with ~15 mL of 2- propanol and dried under vacuum. Further purification can be achieved via column chromatography in cyclohexane / ethyl acetate.

Via this 12.1 g of pure 3-Bromo-5-alpha-carbolino-benzonitrile (uHPLC > 95%) was achieved resulting in a yield of 44%.

Synthesis of the Alpha-Carboline-Ortho-BIMBIM Host

In a dry 500 ml flask, 10,0g (28.72 mmol, 1 eq) of 3-Bromo-5-alpha-carbolino-benzonitrile, 14.1g (34.46, 1.2 eq) of 9-[3-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]BIMBIM and 0.99g (0.86 mmol, 0.03 eq) Pd(PPh3)4 were suspended in 170 mL of a mixture of toluene:dioxane (4:1). This suspension was degassed with nitrogen for 15 min. To this was added, 35 mL (2 eq) of 2M aq. Na2CO3 (degassed using nitrogen for 15 min). Then the reaction volume was evacuated and filled with nitrogen 2 times. The reaction was stirred at 80°C overnight.

For the workup the reaction mixture was diluted with 175 ml of toluene, filtered through celite, washed the celite with 150 ml of toluene, checked the celite for the absence of product, separated the water layer from toluene. Then, the aqueous layer was washed with toluene until product is absent in the aqueous layer. Finally, the toluene layer was evaporated.

For purification the crude product was taken up in 100 ml acetonitrile and heated to 85 °C (bath temperature) for 1h. After this the reaction mixture was cooled to 10 °C and the precipitated product was filtered and washed with 30 ml of acetonitrile. Finally, the product was recrystallized in 75 ml ethanol by heating to 80°C for 1 h. After this it was allowed to cool stepwise to 25°C, and finally 10°C. The obtained solid was filtered, washed with twice with 10 ml of ethanol and dried under vacuum.

Via this 11.8 g of pure (uHPLC > 95%) product was achieved resulting in a yield of 74%.

Fabrication of OLEDs

Fabrication of vapor processed OLED devices

The manufacturing of the OLED devices is performed accordingly to WO 04/058911 with adapted film thicknesses and layer sequences. The following examples V1 and E1 show data of OLED devices.

Substrate pre-treatment of examples V1, E1 to E2:

Glass plates with structured ITO (50 nm, indium tin oxide) form the substrates on which the OLED devices are fabricated.

The OLED devices have in principle the following layer structure: - Substrate,

- ITO (50 nm), - Hole injection layer (HIL) - Hole transporting layer (HTL), - Electron blocking layer (EBL), - Emissive layer (EML), - Hole blocking layer (HBL), - Electron transporting layer (ETL), - Electron injection layer (EIL), - Cathode.

The cathode is formed by an aluminium layer with a thickness of 100 nm. The detailed stack sequence is shown in table A. The materials used for the OLED fabrication are presented in table C. 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 one emitting dopant, which is mixed with the matrix material or matrix materials in a certain proportion by volume by co- evaporation. An expression such as H1:H2:D1 (50%:45%:5%) here means that material H1 is present in the layer in a proportion by volume of 50%, material H2 is present in the layer in a proportion by volume of 45%, and material D1 is present in the layer in a proportion by volume of 5%. Analogously, the electron-transport layer and hole-injection layer may also consist of a mixture of two or more materials.

The OLED devices are characterised by standard methods. For this purpose, the electroluminescence spectra, the current efficiency (measured in cd/A), power efficiency (Im/W) and the external quantum efficiency (EQE, measured in % at 1000 cd/m²) are determined from current/voltage/luminance characteristic lines (IUL characteristic lines) assuming a Lambertian emission profile. The electroluminescence (EL) spectra are recorded at a luminous density of 1000 cd/m² and the CIE 1931 x and y coordinates are then calculated from the EL spectrum. U1000 is defined as the voltage at luminous density of 1000 cd/m². SE1000 represents the current efficiency, LE1000 the power efficiency at 1000 cd/m². EQE1000 is defined as the external quantum efficiency at luminous density of 1000 cd/m².

The device data of various OLED devices are summarized in table B. The example V1 represents the comparative example according to the state-of-the-art. The examples E1 and E2 show data of inventive OLED devices.

In the following section several examples are described in more detail to show the advantages of the inventive OLED devices.

Use of inventive compounds as host material in fluorescent OLEDs

The inventive compounds are especially suitable as a host (matrix) when blended with a phosphorescent blue dopant (emitter) to form the emissive layer of a phosphorescent blue OLED device. Comparative compound for the state-of-the-art is represented by SdT (structures see table C). The use of the inventive compound as a host (matrix) in a phosphorescent blue OLED device results in excellent device data, especially with respect to power efficiency (LE1000) when compared to the state-of-the-art (compare E1 to V1, see device data see table B).

Table A: device stack of vapor processed OLEDs

Table B: device data of vapor processed OLEDs

Table C: Structural formulae of vapor OLED materials

Claims

Claims 1. Compound of formula (1) where the symbols and indices used are as follows:

R stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CHO, CN, C(=O)Ar, P(=O)(Ar)₂, S(=O)Ar, S(=O)₂Ar, N(R')₂, N(Ar)₂, NO₂, Si(R')₃, B(OR')₂, OSO₂R', a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R', where in each case one or more non-adjacent CH₂ groups may be replaced by R'C=CR', C=C, Si(R )₂, Ge(R')₂, Sn(R')₂, C=O, C=S, C=Se, P(=O)(R ), SO, SO₂, O, S or CONR' and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R', or an aryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R'; where two radicals R may form an aliphatic or aromatic ring system together, which may be substituted by one or more radicals R';

Ar is, on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case also be substituted by one or more radicals R';

2. Compound according to claim 1, characterized in that it is selected from the compounds of formulae (1-1) to (1-6),

where the symbols have the definition as given in Claim 1. 3. Compound according to Claim 1 or 2, characterized in that the group Ar¹ is selected from groups of formulae (Ar1-1) to (Ar1-14),

where the dashed bond indicates the bonding to the biphenyl group in formula (1), where the symbol R^x has the definition as given in Claim 1 and where: p is at each occurrence, independently, 0, 1 , 2,

3 or 4; q is at each occurrence, independently, 0, 1 , 2 or 3.

4. Compound according to one or more of the preceding claims, characterized in that the group Ar² is selected from groups of formulae (Ar2-A1) to (Ar2-A15) and (Ar2-B1),

where the dashed bond indicates the bonding to the biphenyl group in formula (1), where the symbol R^Y has the definition as given in Claim 1 and where: s is at each occurrence, independently, 0, 1 , 2, 3 or 4; t is at each occurrence, independently, 0, 1 , 2 or 3.

5. Compound according to one or more of the preceding claims, characterized in that the group Ar¹ is a group of formula (Ar1-1) as defined in claim 3 and the group Ar² is a group of formula (Ar2-A1) or (Ar2-B1) as defined in claim 4.

6. Composition comprising:

- a material selected from the compounds of formula (1) as defined in claim 1 ; and

- a material selected from hole-transporting host materials.

7. Composition comprising:

- a first host material selected from the compounds of formula (1) as defined in claim 1 ;

- a second host material selected from hole-transporting host materials; and

- a third compound selected from phosphorescent emitters, fluorescent emitters and emitters that exhibit TADF (thermally activated delayed fluorescence).

8. Composition according to claim 6 or 7 comprising:

- a first host material selected from the compound of formula (1) as defined in claim 1 ;

- a second host material selected from hole-transporting host materials;

- a third compound selected from phosphorescent emitters and emitters that exhibit TADF;

- a fourth compound selected from phosphorescent emitters and fluorescent emitters.

9. Composition according to one or more of claims 6 to 8, characterized in that the second host material is selected from hole-transporting host materials selected from the group of the carbazole and triarylamine derivatives, more particularly the biscarbazoles, the bridged carbazoles, the triarylamines, the dibenzofuran-carbazole derivatives or dibenzofuran-amine derivatives, and the carbazoleamines.

10. Composition according to one or more of claims 6 to 9, characterized in that the the second host material is selected from hole-transporting host materials selected from compounds of formula (h-1) or (h-2), where:

K is Ar⁴ or -L²-N(Ar)₂; Z is C-R^z or C-R^A; or two adjacent groups Z form a condensed ring together;

R_A is -L³-Ar⁵ or -L¹-N(Ar)2;

L³ is a single bond or an aromatic or heteroaromatic ring system which has 5 to 30 aromatic ring atoms and may be substituted by one or more R radicals, where one radical R on L³ may form a ring with a radical R^z on the carbazole;

Ar⁴ is an aromatic ring system having 6 to 40 aromatic ring atoms or a heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may be substituted by one or more R radicals;

E is on each occurrence, independently, a single bond or a group C(R⁰)₂;

R⁰ is selected on each occurrence, independently, from a straight-chain alkyl group having 1 to 10 carbon atoms or a branched or cyclic alkyl group having 3 to 10 carbon atoms, which may in each case be substituted by one or more R' radicals; x, y are selected, independently, from 0 or 1 , wherein when x or y is 0, then the corresponding group E is absent; and x + y = 1 or 2; with the proviso that the compounds of formulae (h-1) and (h-2) comprise at least one group Z, which stands for R^A; and where R, R' and Ar have the definitions detailed in Claim 1.

11. Composition according to claim 10, characterized in that Ar⁵ is a an unsubstituted or substituted heteroaromatic ring system selected from the groups of formulae (Ar5-1) to (Ar5-6),

where the dashed bond indicates the bonding to L³ or Z;

E¹ is on each occurrence, independently, a single bond or a group C(R⁰)₂; where R⁰ has the same meaning as in claim 10;

R^T, R^V is the same or different at each instance and is selected from H, D, F, Cl,

Br, I, N(Ar)₂, N(R)₂, OAr, SAr, CN, NO₂, OR, SR, COOR, C(=O)N(R)₂, Si(R)₃, B(OR)₂, C(=O)R, P(=O)(R)₂, S(=O)R, S(=O)₂R, OSO₂R, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R radicals, where one or more nonadjacent CH₂ groups may be replaced by Si(R)₂, C=O, NR, O, S or CONR, or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms, preferably 5 to 40 aromatic ring atoms, and may be substituted in each case by one or more R radicals; at the same time, two R^T radicals together may form a ring system and two R^V radicals together may form a ring system; x¹, y¹ are selected, independently, from 0 or 1 , wherein when x¹ or y¹ is 0, then the corresponding group E¹ is absent; with the proviso that x¹ + y¹ = 1 or 2; and where R and Ar have the same definition as in claim 1.

12. Composition according to claim 10 or 11 , characterized in that the second host material is selected from hole-transporting host materials selected from compounds of formula (h-1-1) to (h-2-2),

where the symbols have the same meaning as in claims 1, 10 and 11, and where the indices have the following meaning: x, y, have the same meaning as in claim 10; x¹ ,y¹ have the same meaning as in claim 11; c, f stands, independently, for 0, 1, 2, 3 or 4; d, e stands, independently, for 0, 1, 2 or 3; g stands for0, 1, 2 or 3 if x¹=0; or for 0 ,1 or 2 if x¹=1; h stands for0, 1, 2, 3 or 4 if y¹=0; or for 0, 1, 2 or 3 if y¹=1; k stands for 0, 1, 2, 3 or 4 if x=0; or for 0, 1, 2 or 3 if x=1; and

I stands for0, 1, 2 or 3 if y=0; or for 0, 1 or 2 if y=1.

13. Formulation comprising a compound according to one or more of claims 1 to 5 or a composition according to one or more of Claims 6 to 12, and at least one solvent.

14. Electronic device comprising at least one compound according to one or more of Claims 1 to 5 or a composition according to one or more of Claims 6 to 12.

15. Electronic device according to Claim 14 which is an organic electroluminescent device comprising:

- anode;

- cathode; and - at least one emitting layer, where the emitting layer comprises at least one compound according to one or more of Claims 1 to 5 or a composition according to one or more of Claims 6 to 12.