EP4568964A1 - Materials for organic electroluminescent devices - Google Patents

Abstract

The present invention relates to a heterocyclic compound of formula (1) 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.

6H-Benzimidazolo[1,2-a]benzimidazole (BimBim) is a commonly used building block in the synthesis and development of high triplet energy (T1) host materials for next generation blue organic light emitting diodes (OLED). It was first described in WO11160757A1 and W012130709A1.

There is no conjugation between the two benzene rings in the BimBim structure, which leads to a large gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LIIMO), and therefore a high excited state energy. This is especially favorable for host materials of deep blue OLEDs based on phosphorescence, hyperphosphorescence or hyperfluorescence, because the emitter emission is then unlikely to be quenched by the hosts and high efficiencies can be obtained.

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.

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):

Formula (1 ) where the symbols and indices used are as follows:

Ar¹ is a group of formula (

Formula (Ar1) where the dashed bond indicates the bonding position to the nitrogen in formula (1);

Y is the same or different at each instance and is CR^Y or N, or two groups Y form a condensed ring together, with the proviso that the Y connected with Y¹ are C if p is 1 and CR^Y or N if p is 0; and with the proviso that up to two Y are N each cyclus in the group of formula (Ar1); Y¹ is O, S, CR^Y2 or a single bond; p is 0 or 1 ;

Q is C, Ge or Si;

X is the same or different at each instance and is CR^X or N, or two groups X form a condensed ring together, with the proviso that the X connected with N is C;

R¹, 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)a, 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, one radical R¹ and one radical R^Y, 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.

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:

Ri f i 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 (1-4),

where the symbols have the definition as above.

In accordance with a preferred embodiment, the group Ar¹ of formula (1) is selected from the groups of formulae (Ar1-1) to (Ar1-5)

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 (1-1-1-1) to (1-4- 5-4),

In a preferred embodiment of the invention Q is C and Ar1 is a group of formulae (Ar1-1) to (Ar1-4) or Q is Ge or Si and Ar¹ is a group of formula (Ar-4).

In a preferred embodiment of the invention X stand on each occurrence, identically or differently for CR^X.

In a preferred embodiment of the invention X stand on each occurrence, identically or differently for CR^X and Y stand on each occurrence, identically or differently for CR^Y. In this embodiment no X or Y is N.

In a preferred embodiment of the invention Y stand on each occurrence, identically or differently for CR^Y.

In a preferred embodiment the compound is a compound according to one of the formulae (1-1-1-1) to (1 -1-5-4) or (1-2-1-1) to (1-2-5-4).

Preferred embodiments of the compounds according to formulae (1-1-1-1) to (1-4- 5-4) are shown in the following table:

In a preferred embodiment the compound contains not more than two substituents R that are a group other than H, F, CN or D, preferably other than H or D.

In a preferred embodiment the compound contains not more than two substituents selected from R^x and/or R^Y are a group other than H, F, CN or D, preferably other than H or D.

In a preferred embodiment the compound is a compound according to one of the formulae (1-1-1-1) to (1 -1-5-4) or (1-2-1-1) to (1-2-5-4), preferably according to one of the formulae (1-1-1-1a) to (1-1-5-4a) or (1-2-1-1a) to (1-2-5-4a).

Preferably, R¹, 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, 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, where two radicals R¹ and/or a radical R¹ and a radical R^Y may form an aliphatic, aromatic or heteroaromatic ring system together, which may be substituted by one or more radicals R.

Particularly preferably, R¹, 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, where two radicals R¹ and/or a radical R¹ and a radical R^Y may form an aliphatic, aromatic or heteroaromatic ring system together, which may be substituted by one or more radicals R.

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

In the case of R¹, R^x, R^Y standing for an aromatic or heteroaromatic ring system it is preferred that they are the same or different at each instance and selected from the groups of the following formulae Ar-1 to Ar-83:

Ar-67 Ar-68 where R is as defined above, the dotted bond represents the bond to corresponding carbon atom and, in addition:

Ar³ is the same or different at each instance and is a bivalent aromatic or heteroaromatic ring system which has 6 to 18 aromatic ring atoms and may be substituted in each case by one or more R radicals; A¹ is the same or different at each instance and is NR, O, S or C(R)2; n is 0 or 1 , where n = 0 means that no A¹ group is bonded at this position and R radicals are bonded to the corresponding carbon atoms instead; m is 0 or 1 , where m = 0 means that the Ar³ group is absent and that the corresponding aromatic or heteroaromatic group is bonded directly to the carbon atom.

Particularly preferred Ar groups are Ar-1 , Ar-2, Ar-3, Ar-4, Ar-13 groups with A¹ = O or S, m = 1 and Ar³ = para-phenylene, Ar-13 with m = 0 and A¹ = C(CH3)2 or C(C6Hs)2, Ar-14 with m = 0 and A¹ = C(CH3)2 or C(C6Hs)2, Ar-15 with A¹ = N-phenyl, m = 1 and Ar³ = meta- or para- phenylene, Ar-16 with m = 0 and A¹ = O, S, C(CH3)2 or C(C6Hs)2, Ar-43, Ar-45 and Ar-46, especially the following groups: Ar-1a, Ar-2a, Ar-3a, Ar-4a, Ar-13a with A¹ = O or S, Ar-13b with A¹ = C(CH₃)₂ or C(C₆H₅)2, Ar-14a with A¹ = C(CH₃)₂ or C(C₆H₅)2, Ar-15a, Ar-15b, Ar- 16a with A¹ = O, S, C(CH₃)₂ or C(C₆H₅)2, Ar-43a, Ar-45a and Ar-46a, where the symbols used have the definitions given above.

In a preferred embodiment R¹ stands on each occurrence identically or differently for a straight-chain alkyl group having 1 to 20, preferably 1 to 10, more preferably 1 to 6 C atoms or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, preferably 5 to 18, more preferably 6 to 12 aromatic ring atoms, which may in each case be sub- stituted by one or more radicals R, where two radicals R¹ may form an aliphatic, aromatic or heteroaromatic ring system together, which may be substituted by one or more radicals R.

In a preferred embodiment R¹ stands on each occurrence identically or differently for a straight-chain alkyl group having 1 to 20, preferably 1 to 10, more preferably 1 to 6 C atoms or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, preferably 5 to 18, more preferably 6 to 12 aromatic ring atoms, which may in each case be sub- stituted by one or more radicals R, where two radicals R¹ may form an aliphatic, aromatic or heteroaromatic ring system together, which may be substituted by one or more radicals R, preferably two racidals R¹ may form an aromatic or heteroaromatic ring system via at least one single bond.

In a preferred embodiment R¹ is selected from the groups according to CR3, CR2CR3, Ar-1, Ar-2, Ar-3, Ar-4, preferably Ar-1 and CR3, wherein two R¹ may be connected via a single bond.

Preferably in formula (1-1-1-1) to (1-4-5-4), Q and both R¹ are selected as follows:

In accordance with a very preferred embodiment, the compound of formula (1) is selected from the compounds of formulae (1 -1 - 1 - 1 a) to (1-4-6-4a),

-ML-

-90 k-

Where in formulae (1-1 -1-1 a) to (1-4-5-4a): p, q are selected, identically or differently, from 0, 1 , 2, 3 and 4; and r,s are selected, identically or differently, from 0, 1 , 2, 3, 4 and 5.

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

The present invention therefore further provides a process for preparing the compounds of

35 the invention, characterized by the following steps: (1) synthesizing the base skeleton of the compound of the formula (1) containing a reactive leaving group or H in place of the Ar¹ group, the reactive leaving group preferably selected from boronic acid, boronic ester, Cl, Br, I, triflate, tosylate or mesylate;

(2) introducing the Ar1 group by a coupling reaction.

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 electron- transporting host materials that is preferably selected from the group of the triazines, pyrimidines, quinazolines, quinoxalines and lactams, or derivatives of these structures.

Preferred triazine, pyrimidine, quinazoline or quinoxaline derivatives that can be used as a mixture together with the compounds of the invention are the compounds of the following formulae (e-1), (e-2), (e-3) and (e-4): where R has the meanings given above. R is preferably the same or different at each instance and is H or an aromatic or heteroaromatic ring system which has 6 to 30 aromatic ring atoms and which may be substituted by one or more R¹ radicals.

Preference is given to the compounds of the following formulae (e-1 a) to (e-4a):

where the symbols used have the definitions given above.

Particular preference is given to the triazine derivatives of the formula (e-1) or (e-1a) and the quinoxaline derivatives of the formula (e-4) or (e-4a), especially the triazine derivatives of the formula (e-1) or (e-1 a).

In a preferred embodiment of the invention, Ar in the formulae (e-1 a), (e-2a), (e-3a) and (e- 4a) is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 6 to 30 aromatic ring atoms, especially 6 to 24 aromatic ring atoms, and may be substituted by one or more R radicals. Suitable aromatic or heteroaromatic ring systems Ar here are the same as set out above as embodiments for Ar, especially the structures Ar-1 to Ar-83.

Examples of suitable triazine and pyrimidine compounds that may be used as matrix materials together with the compounds of the invention are the compounds depicted in the following table:

Examples of suitable quinazoline and quinoxaline derivatives are the structures depicted in the following table:

Examples of suitable lactams are the structures depicted in the following table:

Other examples of suitable matrix materials that can be used together with the compounds of the invention are the compounds depicted in the following table:

Preferably, the composition comprises a first host material selected from compounds of the formula (1) as defined above, a second host material selected from electron-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. Suitable phosphorescent compounds (= triplet emitters) are especially compounds which, when suitably excited, emit light, preferably in the visible region, and also contain at least one atom of atomic number greater than 20, preferably greater than 38 and less than 84, more preferably greater than 56 and less than 80, especially a metal having this atomic number. Preferred phosphorescence emitters used are compounds containing copper, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver, gold or europium, especially compounds containing iridium or platinum.

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. Uoyarna et al., Nature 2012, vol. 492, 234). These emitters are organic materials in which the energy gap between the lowest triplet state Ti and the first excited singlet state Si is sufficiently small that the Si state is thermally accessible from the Ti 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 and 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.

In the further layers of the organic electroluminescent device of the invention, it is possible to use any materials as typically used according to the prior art. The person skilled in the art will therefore be able, without exercising inventive skill, to use any materials known for organic electroluminescent devices in combination with the compounds of formula (1) or the above-recited preferred embodiments. 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 compound 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 compound 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 host material in combination with a electron-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 40% by volume, very especially preferably between 97% and 50% 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 electron-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 electron-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 needs to 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 Alqs, 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 above-mentioned 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, U2O, 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-I-ASER). 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

CAS: 1537905-39-7

5-(9H-carbazol-3-yl)-5H-benzo[d]benzo[4,5]imidazo[1 ,2-a]imidazole (CAS: 1537905-39-7) is synthesized in analogy to WO2014009317A1.

Example 1 :

5-(9-(9,9'-spirobi[fluoren]-4-yl)-9H-carbazol-3-yl)-5H-benzo[d]benzo[4,5]imidazo[1,2- a]imidazole

5-fluoro-9,9'-spirobi[fluorene] (25.12 g; 72.80 mmol; 1.00 eq.), 5-(9H-carbazol-3-yl)-5H- benzo[d]benzo[4,5]imidazo[1,2-a]imidazole (34.07 g; 87.36 mmol; 1.20 eq.) and Cesiumcarbonate (47.92 g; 145.60 mmol; 2.00 eq.) were added to 800 ml Dimethylacetamide and stirred under nitrogen for 30 min. After this it was heated for 48 h to 150°C. After cooling to room temperature, the solvent was distilled off and the residue was taken up in dichloromethane and water. The water phase was extracted twice with dichloromethane. After combining the organic phases, the mixture was washed with brine and dried with sodium sulfate. After evaporation of the solvent the crude product was chromatographically purified resulting in 49 g of final product (yield 98%).

The following molecules can be synthesized in the same way by changing the starting materials:

4-Fluoro-9,9-dimethyl-9H-fluorene (CAS: 2420524-96-3) is synthesized by the following reaction sequence:

CAS: 2420524-96-3 a) Suzuki reaction: Methyl 2-brom benzoate 99% (50.0 g; 230 mmol; 1.0 eq.), 2- fluorophenylboronic acid (32.3 g; 230 mmol; 1.0 eq.) and K2CO3 (63.6 g; 460 mmol; 2.0 eq.) are suspended in acetonitrile (750 ml) and ethanol (500 ml) under argon.

Bis(triphenylphosphin)Pd(ll) chloride (3.2 g; 4.6 mmol; 0.02 eq.) are added and the reaction mixture is heated under reflux for 20 hrs. After cooling to room temperature the mixture is poured onto water and extracted with ethyl acetate. The combined organic layers are dried over Na2SC>4 and the solvent is removed in vacuo. The crude product is purified via silica column chromatography and methyl 2'-fluoro-[1 ,1'-biphenyl]-2-carboxylate (47 g, 87%) is obtained as colourless oil. b) Grignard reaction: Cerium(lll) chloride (5.6 g; 22.6 mmol; 1.05 eq.) are heated up to 80 °C under argon for 1 hour. After cooling to room temperature methyl 2'-fluoro-[1 ,1'- biphenyl]-2-carboxylate (5.0 g; 21.5 mmol; 1.0 eq.) and THF (165 ml) are added. The reaction mixture is cooled to 2 °C and methylmagnesiumchlorid 3.0M in THF (21.5 ml; 64 mmol; 3.0 eq.) are added dropwise. Stirring is continued at room temperature over night. The mixture is poured into aqueous ammonia solution and it is extracted with ethyl acetate. The combined organic layers are dried over Na2SC>4 and the solvent is removed in vacuo. Crude 2-{2'-fluoro-[1,1'-biphenyl]-2-yl}propan-2-ol (6.5 g) is obtained as yellow oil. c) Condensation: 2-{2'-fluoro-[1,1'-biphenyl]-2-yl}propan-2-ol (43.7 g; 185 mmol; 1.0 eq.) and Amberlyst 15 (17.8 g; 185 mmol; 1.0 eq.) are dissolved in toluene (1.5 I) and the reaction mixture is stirred under reflux for 48 hrs. After cooling to room temperature the amberlyst is filtered off and the solvent is removed in vacuo. The crude product is dissolved in heptane and filtered over silica and the solvent is removed in vacuo. 4-Fluoro-9,9- dimethyl-9H-fluorene (35.5 g, 89%) is obtained as colourless crystals.

Example 3:

5-(9-(Triphenylsilylphen-3-yl)-9H-carbazol-3-yl)-5H-benzo[d]benzo[4,5]imidazo[1,2- a]imidazole

3-(Bromophenyl)triphenylsilane (32.3 g; 77.3 mmol; 1.10 eq.), 5-(9H-carbazol-3-yl)-5H- benzo[d]benzo[4,5]imidazo[1,2-a]imidazole (19.4 g; 50.6 mmol; 0.72 eq.), K3PO4 (46.2 g; 211 mmol; 3,0 eq.) and Cul (4.0 g; 21.1 mmol; 0,30 eq.) are added to 1 ,4-dioxane (500 ml) and trans-1,2-diaminocyclohexane (DACH) (85 ml; 703 mmol; 10,00 eq.) and the suspension is degassed under argon. It is then heated to 100 °C for 2 days. After cooling to room temperature the reaction mixture is poured onto 500 ml aqueous ammonia (25%) and stirring is continued for 2 hrs. The product is extracted with toluene. The volumne of the solution is reduced and the resulting precipitate is collected and washed with methanol. The crude product is recrystallized from toluene to give 27 g (36 mmol, 52%) of the product as white solid.

The following molecules can be synthesized in the same way by changing the starting material:

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 , E1 and E2 show data of OLED devices.

Glass plates with structured ITO (50 nm, indium tin oxide) are pre-treated with an oxygen plasma, followed by an argon plasma. The pre-treated glass plates 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 B.

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 phosphorescent material. The phosphorescent material is mixed with the matrix material or matrix materials in a certain proportion by volume by co-evaporation. An expression such as HH:EH:D (42%:43%:15%) here means that material HH is present in the layer in a proportion by volume of 42%, material EH is present in the layer in a proportion by volume of 43% and material D is present in the layer in a proportion by volume of 15%. 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 and the external quantum efficiency (EQE, measured in %) 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. U is defined as the voltage, which is required for a current density of 10 mA/cm². The parameter EQE represents the external quantum efficiency at a current density of 10 mA/cm². The lifetime LT90 is defined as the time after which the luminance drops from the starting luminance to a proportion of 90% of the starting luminance in the course of operation with a constant current density of 5 mA/cm². The device data of various OLED devices are summarized in table A and table C. The example V1 represents a comparative example according to the state of the art. The examples E1 and E2 show data of inventive OLED devices that use an Ir-complex as emitter. The examples E3, E4, and E5 show data of inventive OLED devices that use an Pt-complex as emitter.

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 an electron-conducting host material and a phosphorescent emitter to form the emissive layer of a phosphorescent blue OLED device. The representative examples use HH1, HH2, and HH3 as host materials. Moreover, in the given examples E1 - E5 in table A and C the host compounds HH1, HH2, and HH3 can be exchanged by the compound HH4.

A comparative compound for the state of the art is represented by StA (structures see table B). 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 lifetime LT90 when compared to the state of the art. This technical advantage is apparent when examples E1 and E2 are compared to V1 in table A. Here, the inventive host compounds HH1 and HH2 in E1 and E2 can also be exchanged with the inventive compound HH4.

The use of the inventive compounds as a host (matrix) in a phosphorescent blue OLED device that incorporate a Pt-complex as emitter results in excellent device data, especially with respect to lifetime LT90. This is apparent in the examples E3 and E4 in table C, where HTM2 is selected from a fluorenamine compound. Moreover, the inventive host compounds HH2 and HH3 in E3 and E4 can also be exchanged with the inventive compound HH4.

Moreover, the use of the inventive compounds as an electron blocking material in the EBL in a phosphorescent blue OLED results in excellent device data, especially with respect to lifetime LT90 and operational voltage II. This is apparent when comparing example E5 and E4 in table C, where HTM2 is selected from fluorenamine compounds. Here, the inventive host compound HH3 in E4 and E5 can also be exchanged with the inventive compound HH4.

Table A: Device stack and performance data of vapor processed OLEDs with Ir-complex as emitter

Table B: Structural formulae of vapor processed OLED materials Table C: Device stack and performance data of vapor processed OLEDs with Pt- complex as emitter

Claims

Claims Compound of formula (1) where the symbols and indices used are as follows: Ar1 is a group of formula (Ar1), Formula (Ar1) where the dashed bond indicates the bonding position to the nitrogen in formula (1); Y is the same or different at each instance and is CRY or N, or two groups Y form a condensed ring together, with the proviso that the Y connected with Y1 are C if p is 1 and CRY or N if p is 0; and with the proviso that up to two Y are N each cyclus in the group of formula (Ar1); Y1 is O, S, CRY2 or a single bond; p is 0 or 1 ; Q is C, Ge or Si; X is the same or different at each instance and is CRX or N, or two groups X form a condensed ring together, with the proviso that the X connected with N is C; R1, Rx, RY 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)a, 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, one radical R1 and one radical RY, two radicals Rx , two radicals Ry 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. Compound according to Claim 1 , characterized in that it is selected from the compounds of formulae (1-1) to (1-4), where the symbols have the definition as given in Claim 1. Compound according to Claim 1 or 2, characterized in that the group Ar1 is selected from groups of formulae (Ar1-1) to (Ar1-5), where the symbols have the definition as given in Claim 1. Compound according to one or more of the preceding claims, characterized in that the compound of formula (1) is selected from the compounds of formulae (1-1-1-1) to (1-4- Compound according to one or more of the preceding claims, characterized in that the Q is C and Ar1 is a group of formulae (Ar1-1) to (Ar1-4) as defined in Claim 3 or Q is Ge or Si and Ar1 is a group of formula (Ar-4) as defined in Claim 3. Compound according to one or more of the preceding claims, characterized in that the compound contains not more than two substituents R that are a group other than H, F, CN or D. Compound according to one or more of the preceding claims, characterized in that the compound contains not more than two substituents selected from Rx and/or RY are other than H, F, CN or D. Compound according to one or more of the preceding claims characterized in that no X or Y is N. Compound according to one or more of the preceding claims characterized in that the compound is a compound according to one of the formulae (1-1-1-1) to (1 -1 -5-4) or (1- 2-1-1) to (1-2-5-4). Process for preparing a compound according to one or more of Claims 1 to 9, characterized by the following steps:

(1) synthesizing the base skeleton of the compound of the formula (1) containing a reactive leaving group or H in place of the Ar¹ group;

(2) introducing the Ar1 group by a coupling reaction. Formulation comprising at least one compound according to one or more of Claims 1 to 9 and at least one solvent. Use of a compound according to one or more of Claims 1 to 9 in an electronic device. Electronic device comprising at least one compound according to one or more of Claims 1 to 9. Electronic device according to Claim 13 which is an organic electroluminescent device, characterized in that the compound according to one or more of Claims 1 to 9 is used in an emitting layer in combination with at least one phosphorescent emitter. Electronic device according to Claim 14, characterized in that the emitting layer contains at least one further material selected from the compounds of the formulae (e- 1), (e-2), (e-3) and (e-4)

Formula (e-1 ) Formula (e-3) Formula (e-4) where R is the same or different at each instance and is H or an aromatic or heteroaromatic ring system which has 6 to 30 aromatic ring atoms and which may be substituted by one or more R¹ radicals.