Materials for organic electroluminescent devices

The present invention relates to a compound of the formula (1 ), to the use of the compound in an electronic device, and to an electronic device comprising a compound of the formula (1 ). The present invention furthermore relates to a process for the preparation of a compound of the formula (1 ) and to a formulation comprising one or more compounds of the formula (1 ).

The structure of organic electroluminescent devices (OLEDs) in which organic semiconductors are employed as functional materials is described, for example in US 4539507. The emitting materials employed here are very often organometallic complexes which exhibit phosphorescence. For quantum-mechanical reasons, an up to four-fold increase in efficiency is possible using phosphorescent instead of fluorescent emitters. In general, however, there is still a need for improvement in the case of OLEDs, in particular also in the case of OLEDs which exhibit triplet emission (phosphorescence), for example with respect to efficiency, operating voltage and lifetime.

The properties of phosphorescent OLEDs are not only determined by the triplet emitters but also by the other materials used together with triplet emitters in OLEDs, such as matrix materials, also called host materials. Improvements in these materials and their charge-transport properties can thus also result in significant improvements in the OLED properties.

Thus, the choice of the matrix material in an emission layer comprising a phosphorescent emitter has a great influence on OLEDs properties, especially in terms of efficiency. The matrix material limits the quenching of excited states of emitter molecules by energy transfer.

The object of the present invention is the provision of compounds, which are suitable for use in an OLED, in particular as matrix material for phosphorescent emitters. A further object of the present invention is to provide further organic semiconductors for organic electroluminescent devices to provide the person skilled in the art with a greater possible choice of materials for the production of OLEDs.

Compounds comprising lactam derivatives and their use in OLEDs are known from the prior art (for example in WO 201 1/137951 and WO 2013/064206).

Surprisingly, it has now been found that certain compounds containing lactam derivatives combined with triphenylene derivatives, as described in greater detail below, exhibit excellent properties when they are employed in OLEDs, particularly when employed as matrix material for phosphorescent emitters. Indeed, these compounds lead to OLEDs exhibiting better properties in terms of lifetime and/or efficiency and/or electroluminescent emission. In addition, these compounds have a high glass transition temperature and a good thermal stability, which is an important property for OLED materials, especially when the materials are vapor- deposited via a vacuum process. It has also been found that specific mixtures of compounds containing lactam derivatives combined with triphenylene derivatives and compounds as described below lead to particularly suitable mixtures for the fabrication of OLEDs.

The present invention therefore relates to these compounds and to electronic devices, in particular organic electroluminescent devices, which comprise compounds of this type. The present invention also relates to mixtures and formulations comprising this mixture.

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

formula (1 )

where the following applies to the symbols and indices used:

Ar ¹ stands on each occurrence, identically or differently, for 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 ¹ ;

Ar ² stands on each occurrence, identically or differently, for 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 ² ;

Ar ³ stands on each occurrence, identically or differently, for 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 ³ ;

-E- is selected from a single bond, -B(R°)-, -C(R°) _2-> -Si(R°)2-, -C(=0)-, -C(=NR°)- , -C(=C(R°) ₂ )-, -0-, -S-, -S(=0)-, -S(0 ₂ )-, -N(R°)-, -P(R°)- and -P((=0)R°)-;

R°, R ¹ , R ² , R ³ stand on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CHO, CN, N(Ar) ₂ , C(=0)Ar, P(=0)(Ar) ₂ , S(=0)Ar, S(=0) ₂ Ar, N0 ₂ , Si(R) ₃ , B(OR) ₂ , OS0 ₂ R, 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 CH ₂ groups may be replaced by RC=CR, CºC, Si(R) ₂ , Ge(R) ₂ , Sn(R) ₂ , C=0, C=S, C=Se, P(=0)(R), SO, S0 ₂ , O, S or CONR and where one or more FI atoms may be replaced by D, F, Cl, Br, I, CN or N0 ₂ , an aromatic or heteroaromatic ring systems 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 40 aromatic ring atoms, which may be substituted by one or more radicals R, where two radicals R°, two radicals R ¹ , two radicals R ² and/or two radicals R ³ may form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system with one another, 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, N(Ar) _2, C(=0)Ar, P(=0)(Ar) ₂ , S(=0)Ar, S(=0) ₂ Ar, N0 ₂ , Si(R ) ₃ , B(OR ) ₂ , OS0 ₂ R ^' , a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or branched or 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 CH ₂ groups may be replaced by R C=CR , CºC, Si(R ) ₂ , Ge(R ) ₂ , Sn(R ) ₂ , C=0, C=S, C=Se, P(=0)(R ), SO, S0 ₂ , O, S or CONR and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or N0 ₂ , an aromatic or heteroaromatic ring systems 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 40 aromatic ring atoms, which may be substituted by one or more radicals R , where two radicals R may form a ring system with one another, which may be substituted by one or more radicals R ^' ;

Ar is an aromatic or heteroaromatic ring system having 5 to 24 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 FI, 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 CFI ₂ groups may be replaced by SO, S0 ₂ , O, S and where one or more FI atoms may be replaced by D, F, Cl, Br or I, or an aromatic or heteroaromatic ring system having 5 to 24 C atoms; n is 0 or 1 ; wherein when n is 0, the group -E- is absent; characterized in that at least one group Ar ³ , R ¹ , R ² or R ³ stands for a

triphenylene derivative of the formula (T),

formula (T)

where the dashed bond indicates the bonding to the structure of formula (1 );

R ⁴ is C at the position of the bonding to Ar ^s or, R ⁴ is C at the position of the bonding to the structure of formula (1 ) if m is 0;

and at other positions, R ⁴ stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CHO, CN, N(Ar) ₂ , C(=0)Ar, P(=0)(Ar) ₂ , S(=0)Ar, S(=0) ₂ Ar, N0 ₂ , Si(R)3, B(OR) ₂ , OS0 ₂ R, 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 CH ₂ groups may be replaced by RC=CR, CºC, Si(R) ₂ , Ge(R) ₂ , Sn(R) ₂ , C=0, C=S, C=Se, P(=0)(R), SO, S0 ₂ , O, S or CONR and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or N0 ₂ , an aromatic or heteroaromatic ring systems 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 40 aromatic ring atoms, which may be substituted by one or more radicals R, where two radicals R ⁴ may form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system, which may be substituted by one or more radicals R;

Ar ^s is 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; m is an integer selected from 0, 1 , 2, 3 or 4, and where the following compounds are excluded:

Adjacent substituents in the sense of the present invention are substituents which are bonded to carbon atoms which are linked directly to one another or which are bonded to the same carbon atom.

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; a heteroaryl group in the sense of this invention contains 5 to 60 aromatic ring atoms, at least one of which is a heteroatom. The hetero atoms 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, phen- anthrene, pyrene, dihydropyrene, chrysene, perylene, fluoranthene, benz- anthracene, benzophenanthrene, tetracene, pentacene, benzopyrene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzo- thiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, pyridine, quinoline, isoquinoline, acridine, phenanthridine, benzo-5, 6-quinoline, benzo-6,7- quinoline, benzo-7, 8-quinoline, phenothiazine, phenoxazine, pyrazole, indazole, imidazole, benzimidazole, naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazinimidazole, quinoxalinimidazole, oxazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, 1 ,2-thiazole, 1 ,3-thiazole, benzo- thiazole, pyridazine, benzopyridazine, pyrimidine, benzopyrimidine, quinoxaline, pyrazine, phenazine, naphthyhdine, azacarbazole, benzocarboline, phenan- throline, 1 ,2,3-thazole, 1 ,2,4-triazole, benzotriazole, 1 ,2,3-oxadiazole, 1 ,2,4-oxa- diazole, 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-thazine, 1 ,2,3-thazine, 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. A heteroaromatic ring system in the sense of this invention contains 5 to 60 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 hetero- aromatic 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 sp ³ -hybridised C, Si, N or O atom, an sp ² - 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, dibenzothiophene, pyrrole, indole, isoindole, carbazole, indolocarbazole, indenocarbazole, pyridine, quinoline, iso- quinoline, acridine, phenanthridine, benzo-5, 6-quinoline, benzo-6, 7-quinoline, benzo-7, 8-quinoline, phenothiazine, phenoxazine, pyrazole, indazole, imidazole, benzimidazole, naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazin- imidazole, quinoxalinimidazole, oxazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, 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, aza- carbazole, benzocarboline, phenanthroline, 1 ,2,3-triazole, 1 ,2,4-triazole, benzo- triazole, 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, 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 CFte 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-methyl butyl, 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-methyl butoxy, n-hexoxy, cyclohexyloxy, n-heptoxy, cycloheptyloxy, n-octyloxy, cyclooctyloxy, 2-ethyl hexyloxy, pentafluoroethoxy, 2,2,2-trifluoroethoxy, 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, pentafluoroethylthio, 2,2,2-trifluoroethylthio, ethenylthio, propenylthio, butenylthio, pentenylthio, cyclopentenylthio, hexenylthio, cyclohexenylthio, heptenylthio, cycloheptenylthio, octenylthio, cyclooctenylthio, ethynylthio, propynylthio, butynylthio, pentynylthio, hexynylthio, heptynylthio 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:

Ring formation

H R: -CH=CH ₂

R R

Furthermore, 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

Preferably, the compounds of formula (1 ) are selected from the compounds of formulae (1A) or (1 B),

formula (1A) formula (1 B)

where

the symbol -E- has the same meaning as above;

X is CR ¹ or N;

Y is CR ² or N;

where the symbols R ¹ , R ² have the same meaning as above; and

Ar ³ has the same meaning as above, with the proviso that Ar ³ in formula (1 B) is connected to the group -E- and the atom N via two adjacent C atoms as represented in formula (1 B); characterized in that, in the compounds of formula (1A), at least one group Ar ³ , R ¹ or R ² stands for a triphenylene derivative of the formula (T) and, in the compounds of formula (1 B), at least one group R ¹ or R ² stands for a triphenylene derivative of the formula (T).

In accordance with the invention, when the group -E- is a single bond, then the compounds of formula (1 B) correspond to compounds of formula (1 B-E),

formula (1 B-E)

where the symbols have the same meaning as above.

More preferably, the compounds of formula (1 ) are selected from the compounds of formulae (2), (3), (4), (5), (6) or (7),

formula (2)

formula (5) formula (6)

formula (7) where the symbols and indices E, R ⁴ , Ar ^s and m have the same meaning as above; and where

X is CR ¹ or N, with the proviso that X is C at the position of the bonding to Ar ^s or, if m is 0 and Ar ^s is absent, to the triphenylene group in formulae (4) and (6);

Y is CR ² or N, with the proviso that Y is C at the position of the bonding to Ar ^s or, if m is 0 and Ar ^s is absent, to the triphenylene group in formulae (3) and (5);

V is CR ³ or N, with the proviso that V is C at the position of the bonding to Ar ^s or, if m is 0 and Ar ^s is absent, to the triphenylene group in formula (7); or two adjacent groups V stand for a group of formula (V-1 ) or (V-2), formula (V-1 ) formula (V-2) where the symbols ^v indicate the corresponding adjacent groups V in formulae (2) to (7);

E° stands for -C(R°) _2-> -Si(R°)2-, -C(=0)-, -C(=NR ⁰ )-, -C(=C(R°) ₂ )-, -0-, -S-, - S(=0)-, -S(0 ₂ )-, -N(R ⁰ )-, -P(R ⁰ )- or -P((=0)R°)-, preferably for -C(R ⁰ ) ₂ -,-O-, - S-, or -N(R ⁰ )-; where R° has the same meaning as above;

W stands for CR or N;

In accordance with a preferred embodiment, the index m is equal to 0 or 1 . When m is 0, then the group Ar ^s is absent and the group -(Ar ^s )o- corresponds to a single bond.

In accordance with a preferred embodiment, there is 0 or 1 group X standing for N in the six-membered ring comprising the groups X, there is 0 or 1 group Y standing for N in the six-membered ring comprising the groups Y, and there is 0 or 1 group V in the six-membered ring comprising the groups V.

Particularly preferably, the compounds of formula (1 ) are selected from the compounds of formulae (2A) to (7B),

formula (3A) formula (3B)

formula (5A) formula (5B)

formula (7A) formula (7B) where the symbols -E-, Ar ^s , R ⁴ , X, Y and V have the same meaning as above.

Very particularly preferably, the compounds of formula (1 ) are selected from the compounds of formulae (2A-1 ) to (7B-1 ),

formula (2A-1 ) formula (2B-1) o ua -

22

formula (4B-1)

formula (4B-2)

formula (6A-2) formula (6A-1) 2)

where the symbols E, X, Y and V have the same meaning as above.

In accordance with a preferred embodiment, -E- is selected from a single bond, -C(R°)2-, -0-, -S- and -N(R ⁰ )-. More preferably, -E- is selected from a single bond, -O- or -S-. Particularly preferably, -E- is a single bond. Preferably, Ar ^s is an aromatic or heteroaromatic ring system having 5 to 40, more preferably 5 to 30, particularly preferably 5 to 18 aromatic ring atoms, which may in each case also be substituted by one or more radicals R; and

More preferably, the group Ar ^s stands on each occurrence, identically or differently, for phenyl, biphenyl, fluorene, spirobifluorene, naphthalene, phenanthrene, anthracene, dibenzofuran, dibenzothiophene, carbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, benzopyridine, benzopyridazine, benzopyrimidine and quinazoline, each of which may be substituted by one or more radicals R.

In accordance with a very preferred embodiment, the group Ar ^s stands on each occurrence, identically or differently, for phenyl, biphenyl, fluorene, naphthalene, dibenzofuran, dibenzothiophene and carbazole, each of which may be substituted by one or more radicals R.

Examples of suitable groups Ar ^s are the groups (Ar ^s -1 ) to (Ar ^s -22) depicted in the table below:

where the dashed bonds indicate the bonds to the structure of formula (1 ) and to the triphenylene derivative, and where the groups (Ar ^s -1 ) to (Ar ^s -22) may be substituted at each free position by a group R and where:

R ^N , R ^c in formulae (Ar ^s -13) to (Ar ^s -16), are on each occurrence, identically or differently, H, D, F, Cl, Br, I, CN, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40, preferably 1 to 20, more preferably 1 to 10 C atoms or cyclic alkyl, alkoxy or thioalkoxy 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 one or more non-adjacent CFte groups may be replaced by (R)C=C(R), CºC, O or S and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO ₂ , or an aromatic or heteroaromatic ring system having 5 to 60, preferably 5 to 40, more preferably 5 to 30, very more preferably 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R, where optionally two adjacent substituents R ^c can form a mono- or polycyclic, aliphatic, aromatic or hetero- aromatic ring system with one another.

Examples of very suitable groups Ar ^s are the groups (Ar ^s -23) to (Ar ^s -67) depicted in the table below:

where the dashed bonds indicate the bonds to the structure of formula (1 ) and to the triphenylene derivative and where the groups (Ar ^s -23) to (Ar ^s -67) may be substituted at each free position by a group R.

Preferably, R° stands on each occurrence, identically or differently, for H, D, F, CN, a straight-chain alkyl group having 1 to 20 C atoms or branched or a cyclic alkyl group having 3 to 20 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non-adjacent CFh groups may be replaced by RC=CR, CºC, O or S and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2, an aromatic or heteroaromatic ring systems 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, or an aryloxy group having 5 to 40, preferably 5 to 30, more preferably 5 to 18 aromatic ring atoms, which may be substituted by one or more radicals R, where two radicals R° may form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system with one another, which may be substituted by one or more radicals R. More preferably, R° stands on each occurrence, identically or differently, for H, D, a straight-chain alkyl group having 1 to 10 C atoms or branched or a cyclic alkyl group having 3 to 10 C atoms, each of which may be substituted by one or more radicals R, an aromatic or heteroaromatic ring systems having 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R, where two radicals R° may form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system with one another, which may be substituted by one or more radicals R.

Preferably, R ¹ , R ² , R ³ stand on each occurrence, identically or differently, for H, D, F, CN, Si(R)3, a straight-chain alkyl or alkoxy group having 1 to 20 C atoms or branched or a cyclic alkyl or alkoxy group having 3 to 20 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non-adjacent CFh groups may be replaced by RC=CR, CºC, O or S and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2, an aromatic or heteroaromatic ring systems 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 40 aromatic ring atoms, which may be substituted by one or more radicals R, where two radicals R ¹ , two radicals R ² and/or two radicals R ³ may form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system with one another, which may be substituted by one or more radicals R. More preferably, R ¹ , R ² , R ³ stand on each occurrence, identically or differently, for FI, D, F, CN, a straight-chain alkyl group having 1 to 10 C atoms or branched or a cyclic alkyl group having 3 to 10 C atoms, each of which may be substituted by one or more radicals R, or an aromatic or heteroaromatic ring systems having 5 to 60, preferably 5 to 40, more preferably 5 to 30, very more preferably 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R, where two radicals R ¹ , two radicals R ² and/or two radicals R ³ may form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system with one another, which may be substituted by one or more radicals R.

When the groups R ¹ , R ² or R ³ stands for an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, then the aromatic or heteroaromatic ring system is preferably selected from benzene, naphthalene, anthracene, benzanthracene, phenanthrene, triphenylene (also called benzophenanthrene), pyrene, chrysene, perylene, fluoranthene, naphthacene, pentacene, benzopyrene, biphenyl, biphenylene, terphenyl, terphenylene, quaterphenyl, fluorene, spirobifluorene, indenofluorene, furan, benzofuran, dibenzofuran, thiophene, benzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carba- zole, indolocarbazole, indenocarbazole, pyridine, quinoline, isoquinoline, acridine, phenanthridine, benzoquinoline, phenothiazine, phenoxazine, imidazole, benzimidazole, naphthimidazole, phenanthrimidazole, pyrimidine, benzo- pyrimidine, quinoxaline, pyrazine, phenazine, phenoxazine, phenothiazine, aza- carbazole, triazine, or combinations of these groups. More preferably, when the groups R ¹ , R ² or R ³ stands for an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, then the aromatic or heteroaromatic ring system is selected from benzene, naphthalene, phenanthrene, triphenylene, fluoranthene, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene, indenofluorene, dibenzofuran, dibenzothiophene, carbazole, indolocarbazole, indenocarbazole, pyridine, quinoline, benzoquinoline, pyrimidine, benzopyrimidine, quinoxaline, phenoxazine, phenothiazine, azacarbazole, triazine, or combinations of these groups.

Preferably, R ⁴ stands on each occurrence, identically or differently, for H, D, F, Si(R)3, a straight-chain alkyl or alkoxy group having 1 to 20 C atoms or branched or a cyclic alkyl or alkoxy group having 3 to 20 C atoms, each of which may be substituted by one or more radicals R, where in each case one or more non- adjacent CFh groups may be replaced by RC=CR, CºC, O or S and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2, an aromatic or heteroaromatic ring systems having 5 to 60, preferably 5 to 40, more preferably 5 to 30, very more preferably 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R, where two radicals R ⁴ may form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system, which may be substituted by one or more radicals R. More preferably, R ⁴ stands on each occurrence, identically or differently, for FI, D, F, a straight-chain alkyl group having 1 to 10 C atoms or branched or a cyclic alkyl group having 3 to 10 C atoms, each of which may be substituted by one or more radicals R, an aromatic or heteroaromatic ring systems having 5 to 60, preferably 5 to 40, more preferably 5 to 30, very more preferably 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R, where two radicals R ⁴ may form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system, which may be substituted by one or more radicals R. Particularly preferably, R ⁴ stands on each occurrence, identically or differently, for FI, D, a straight-chain alkyl group having 1 to 10 C atoms or a branched or a cyclic alkyl group having 3 to 10 C atoms, each of which may be substituted by one or more radicals R, or an aromatic or heteroaromatic ring systems having 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R.

Preferably, R stands on each occurrence, identically or differently, for H, D, F,

CN, a straight-chain alkyl or alkoxy group having 1 to 20 C atoms or branched or cyclic alkyl or alkoxy group having 3 to 20 C atoms, each of which may be substituted by one or more radicals R ^' , an aromatic or heteroaromatic ring systems 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 R may form a ring system with one another, which may be substituted by one or more radicals R ^' . More preferably, R stands on each occurrence, identically or differently, for H, D, F, CN, a straight-chain alkyl group having 1 to 10 C atoms or branched or cyclic alkyl group having 3 to 10 C atoms, each of which may be substituted by one or more radicals R ^' , an aromatic or heteroaromatic ring systems having 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R . Preferably, Ar is an aromatic or heteroaromatic ring system having 5 to 18 aromatic ring atoms, which may in each case also be substituted by one or more radicals R .

Preferably, R stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CN, a straight-chain alkyl or alkoxy group having 1 to 20, preferably 1 to 10, more preferably 1 to 5 C atoms or branched or cyclic alkyl or alkoxy group having 3 to 20, preferably 1 to 10, more preferably 1 to 5 C atoms, 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 C, preferably 5 to 18 C atoms.

In accordance with a preferred embodiment, the compounds of formula (1 ) comprise at least one substituent R ¹ or R ² , which is selected from aromatic and heteroaromatic ring systems.

Examples of suitable compounds according to the invention are the structures shown in the table below:

-41

The compounds according to the invention can be prepared by synthesis steps known to the person skilled in the art, such as, for example, bromination, Suzuki coupling, Ullmann coupling, Hartwig-Buchwald coupling, etc. Examples of suitable synthesis processes are depicted in general terms in Schemes 1 and 2 below.

Scheme 1 - Amination triphenylene with lactam

where X in scheme 1 is a leaving group, preferably selected from halogens (like Br, Cl, I), boronic acids and triflates, and where the other symbols and indices have the same meaning as above.

Scheme 2 - C-C coupling triphenylene with lactam where X ¹ and X ² , in scheme 2, are leaving groups, preferably selected from halogens (like Br, Cl, I), boronic acids and triflates, and where the other symbols and indices have the same meaning as above.

For the processing of the compounds according to the invention from the liquid phase, for example by spin coating or by printing processes, formulations of the compounds according to the invention are necessary. These formulations can be, for example, solutions, dispersions or emulsions. It may be preferred to use mixtures of two or more solvents for this purpose. Suitable and preferred solvents are, for example, toluene, anisole, o-, m- or p-xylene, methyl benzoate, mesitylene, tetralin, veratrol, THF, methyl-TFIF, THP, chlorobenzene, dioxane, phenoxytoluene, in particular 3-phenoxytoluene, (-)-fenchone, 1 ,2,3,5- tetramethylbenzene, 1 ,2,4,5-tetramethylbenzene, 1 -methylnaphthalene, 2-methylbenzothiazole, 2-phenoxyethanol, 2-pyrrol id inone, 3-methylanisole, 4-methylanisole, 3,4-dimethylanisole, 3,5-dimethylanisole, acetophenone, a-terpineol, benzothiazole, butyl benzoate, cumene, cyclohexanol, cyclo- hexanone, cyclohexyl benzene, 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 or mixtures of these solvents.

The present invention therefore furthermore relates to a formulation comprising a compound according to the invention and at least one further compound. The further compound may be, for example, a solvent, in particular one of the above- mentioned solvents or a mixture of these solvents. However, the further compound may also be at least one further organic or inorganic compound which is likewise employed in the electronic device, for example an emitting compound, in particular a phosphorescent dopant, and/or a further matrix material. Suitable emitting compounds and further matrix materials are indicated below in connection with the organic electroluminescent device. This further compound may also be polymeric.

The compounds and mixtures according to the invention are suitable for use in an electronic device. An electronic device here is taken to mean a device which comprises at least one layer which comprises at least one organic compound. However, the component here may also comprise inorganic materials or also layers built up entirely from inorganic materials. The present invention therefore furthermore relates to the use of the compounds or mixtures according to the invention in an electronic device, in particular in an organic electroluminescent device.

The present invention again furthermore relates to an electronic device comprising at least one of the compounds or mixtures according to the invention mentioned above. The preferences stated above for the compound also apply to the electronic devices.

The electronic device is preferably selected from the group consisting of organic electroluminescent devices (OLEDs, PLEDs), organic integrated circuits (O-ICs), organic field-effect transistors (O-FETs), organic thin-film transistors (O-TFTs), organic light-emitting transistors (O-LETs), organic solar cells (O-SCs), organic dye-sensitised solar cells, organic optical detectors, organic photoreceptors, organic field-quench devices (O-FQDs), light-emitting electrochemical cells (LECs), organic laser diodes (O-lasers) and "organic plasmon emitting devices" (D. M. Koller et ai, Nature Photonics 2008, 1 -4), preferably organic electro- luminescent devices (OLEDs, PLEDs), in particular phosphorescent OLEDs.

The organic electroluminescent device comprises a cathode, an anode and at least one emitting layer. Apart from these layers, it may also comprise further layers, for example in each case one or more hole-injection layers, hole-transport layers, hole-blocking layers, electron-transport layers, electron-injection layers, exciton-blocking layers, electron-blocking layers and/or charge-generation layers. It is likewise possible for interlayers, which have, for example, an exciton-blocking function, to be introduced between two emitting layers. However, it should be pointed out that each of these layers does not necessarily have to be present. The organic electroluminescent device here may comprise one emitting layer or a plu- rality of emitting layers. If a plurality of emission layers are present, these prefera- bly have in total a plurality of emission maxima between 380 nm and 750 nm, resulting overall in white emission, i.e. various emitting compounds which are able to fluoresce or phosphoresce are used in the emitting layers. Particular preference is given to systems having three emitting layers, where the three layers exhibit blue, green and orange or red emission (for the basic structure see, for example, WO 2005/011013). These can be fluorescent or phosphorescent emission layers or hybrid systems, in which fluorescent and phosphorescent emission layers are combined with one another.

The compound according to the invention in accordance with the embodiments indicated above can be employed in various layers, depending on the precise structure. Preference is given to an organic electroluminescent device comprising a compound of the formula (1 ) or in accordance with the preferred embodiments as matrix material for fluorescent emitters, phosphorescent emitters or emitters showing TADF (Thermally Activated Delayed Fluorescence), in particular for phosphorescent emitters, and/or in an electron-transport layer and/or in an electron-blocking or exciton-blocking layer and/or in a hole-transport layer, depending on the precise substitution. The preferred embodiments indicated above also apply to the use of the materials in organic electronic devices.

In a preferred embodiment of the invention, the compound of the formula (1 ) or in accordance with the preferred embodiments is employed as matrix material for a fluorescent or phosphorescent compound, in particular for a phosphorescent compound, in an emitting layer. The organic electroluminescent device here may comprise one emitting layer or a plurality of emitting layers, where at least one emitting layer comprises at least one compound according to the invention as matrix material.

If the compound of the formula (1 ) or in accordance with the preferred em- bodiments is employed as matrix material for an emitting compound in an emitting layer, it is preferably employed in combination with one or more phosphorescent materials (triplet emitters). Phosphorescence in the sense of this invention is taken to mean the luminescence from an excited state having spin multiplicity > 1 , in particular from an excited triplet state. For the purposes of this application, all luminescent transition-metal complexes and luminescent lanthanide com- plexes, in particular all iridium, platinum and copper complexes, are to be regarded as phosphorescent compounds.

Preferably, when the compounds of the formula (1 ) or in accordance with the preferred embodiments are employed as matrix materials for an emitting compound in an emitting layer, they are preferably employed in combination with one or more phosphorescent material (triplet emitters).

The mixture comprising the compound of the formula (1 ) or in accordance with the preferred embodiments and the emitting compound comprises between 99 and 1 % by vol., preferably between 98 and 10% by vol., particularly preferably between 97 and 60% by vol., in particular between 95 and 80% by vol., of the compound of the formula (1 ) or in accordance with the preferred embodiments, based on the entire mixture comprising emitter and matrix material. Correspondingly, the mixture comprises between 1 and 99% by vol., preferably between 2 and 90% by vol., particularly preferably between 3 and 40% by vol., in particular between 5 and 20% by vol., of the emitter, based on the entire mixture comprising emitter and matrix material.

Suitable phosphorescent compounds (= triplet emitters) are, in particular, compounds which emit light, preferably in the visible region, on suitable excitation and in addition contain at least one atom having an atomic number greater than 20, preferably greater than 38 and less than 84, particularly preferably greater than 56 and less than 80, in particular a metal having this atomic number. The phosphorescent emitters used are preferably compounds which contain copper, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver, gold or europium, in particular compounds which contain iridium or platinum. For the purposes of the present invention, all luminescent compounds which contain the above-mentioned metals are regarded as phosphorescent compounds. Examples of the emitters described above are revealed by the 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 2014/094962, WO 2014/094961 , WO 2014/094960, WO 2016/124304, WO 2016/125715, WO 2017/032439 as well as the not yet published applications WO 2018/011186 and WO 2018/041769. In general, all phosphorescent complexes as used in accordance with the prior art for phosphorescent OLEDs and as are known to the person skilled in the art in the area of organic electroluminescence are suit- able, and the person skilled in the art will be able to use further phosphorescent complexes without inventive step.

Examples of suitable phosphorescent emitters are the phosphorescent emitters listed in the table below:

Suitable phosphorescent materials (= triplet emitters) that can be

advantageously combined with the compounds of formula (1 ) are, as mentioned above, compounds which emit a red light on suitable excitation, which means phosphorescent materials having an excited triplet state level (T1 ) comprised between 550 and 680 nm.

A further preferred embodiment of the present invention is the use of the compound of the formula (1 ) or in accordance with the preferred embodiments as matrix material for a phosphorescent emitter in combination with a further matrix material. Particularly suitable matrix materials which can be employed in combination with the compounds of the formula (1 ) or in accordance with the preferred embodiments are aromatic ketones, aromatic phosphine oxides or aromatic sulfoxides or sulfones, for example in accordance with WO 2004/013080, WO 2004/093207, WO 2006/005627 or WO 2010/006680, triarylamines, carbazole derivatives, for example CBP (N,N-bis- carbazolylbiphenyl) or the carbazole derivatives disclosed in WO 2005/039246, US 2005/0069729, JP 2004/288381 , EP 1205527 or WO 2008/086851 , indolocarbazole derivatives, for example in accordance with WO 2007/063754 or WO 2008/056746, indenocarbazole derivatives, for example in accordance with WO 2010/136109 and WO 2011/000455, azacarbazole derivatives, for example in accordance with EP 1617710, EP 1617711 , EP 1731584, JP 2005/347160, bipolar matrix materials, for example in accordance with WO 2007/137725, silanes, for example in accordance with WO 005/111172, azaboroles or boronic esters, for example in accordance with WO 2006/117052, triazine derivatives, for example in accordance with WO 2010/015306, WO 2007/063754 or WO 2008/ 056746, zinc complexes, for example in accordance with EP 652273 or WO 2009/062578, diazasilole or tetraazasilole derivatives, for example in accordance with WO 2010/054729, diazaphosphole derivatives, for example in accordance with WO 2010/054730, bridged carbazole derivatives, for example in accordance with US 2009/0136779, WO 2010/050778, WO 2011/042107, WO 2011/088877 or in accordance with EP 11003232.3, triphenylene derivatives, for example in accordance with WO 2012/048781 , or lactams, for example in accordance with WO 2011/116865 or WO 2011/137951. A further phosphorescent emitter which emits at shorter wavelength than the actual emitter may likewise be present in the mixture as co-host.

Preferred co-host materials are triarylamine derivatives, lactams, carbazole derivatives and indenocarbazole derivatives. Preferred co-host materials are very particularly carbazole derivatives and indenocarbazole derivatives.

The present invention therefore furthermore relates to a mixture comprising at least one compound of formula (1 ) or in accordance with the preferred embodi- ments and a second compound comprising at least one group of formula (10),

formula (10) where

R ¹⁰ stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CHO, CN, N(Ar) ₂ , C(=0)Ar, P(=0)(Ar) ₂ , S(=0)Ar, S(=0) ₂ Ar, N0 ₂ , Si(R) ₃ , B(OR) ₂ , OS0 ₂ R, 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 CH ₂ groups may be replaced by RC=CR, CºC, Si(R) ₂ , Ge(R) ₂ , Sn(R) ₂ , C=0, C=S, C=Se, P(=0)(R), SO, S0 ₂ , O, S or CONR and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or N0 ₂ , an aromatic or heteroaromatic ring systems 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 40 aromatic ring atoms, which may be substituted by one or more radicals R, where two radicals R ¹⁰ may form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system with one another, which may be substituted by one or more radicals R;

Ar ¹⁰ is 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; p is an integer selected from 0, 1 , 2, 3 and 4;

T is CR ¹¹ or N; or two adjacent groups T stand for a group of formula (T-1 ),

formula (T-1 ) where the symbols ^v indicate the corresponding adjacent groups T in formula

(10);

E ¹⁰ stands for -C(R°) _2-> -Si(R°)2-, -C(=0)-, -C(=NR ⁰ )-, -C(=C(R°) ₂ )-, -0-, -S-, - S(=0)-, -S(0 ₂ )-, -N(Ar ¹⁰ )-, -P(R ⁰ )- or -P((=O)R ⁰ )-; where R° has the same meaning as above;

Z stands for CR ¹⁰ or N; and

R has the same definition as given above for the group R in formula (1 );

Ar has the same definition as given above for the group Ar in formula (1 ); R has the same definition as given above for the group R in formula (1 ).

Preferably, the second compound comprising at least one group of formula (10) is selected from compounds of formulae (11 ) and (12),

formula (12) where the symbols and indices Ar ¹⁰ , E ¹⁰ , R ¹⁰ and p have the same meaning as above; and E ¹¹ stands for -C(R°) _2-> -Si(R°)2-, -C(=0)-, -C(=NR ⁰ )-, -C(=C(R°) ₂ )-, -0-, -S-, - S(=0)-, -S(0 ₂ )-, -N(Ar ¹⁰ )-, -P(R ⁰ )- or -P((=O)R ⁰ )-;

R° has the same definition as given above for the group R° in formula (1 );

L ¹ is a single bond or 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; where R has the same definition as above.

More preferably, the second compound comprising at least one group of formula (10) is selected from the compounds of formulae (11-1 ) to (12-4),

formula (11-3)

formula (12-3) formula (12-4) where the symbols and indices Ar ¹⁰ , R ¹⁰ , E ¹⁰ , L ¹ and p have the same meaning as above; and

E ¹² stands for -C(R°)2-, -0-, -S-, -N(Ar ¹⁰ )-; where R° has the same meaning as above.

Particularly preferably, the second compound comprising at least one group of formula (10) is selected from the compounds of formulae (13-1 ) to (14-4),

formula (13-1 )

formula (13-4)

formula (14-1 ) formula (14-2)

formula (14-3) formula (14-4) where the symbols and indices R ¹⁰ , E ¹⁰ , E ¹² and p have the same meaning as above; and where:

Ar ¹⁰ stands for an aromatic or heteroaromatic ring system selected from ben- zene, naphthalene, pyrene, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene, cis- or trans-indenofluorene, dibenzofuran, dibenzo- thiophene, carbazole, indolocarbazole, indenocarbazole, which may be substituted by one or more radicals R; or combinations of these groups;

L ² stands for a single bond or an aromatic or heteroaromatic rings system having 6 to 18 aromatic rings atoms, which may be substituted by one or more radicals R; Ar ¹² stands for an heteroaromatic ring system selected from pyridine, pyrazine, pyrimidine, triazine, which may be substituted by one or more radicals R; and

R has the same meaning as above.

In a further embodiment of the invention, the organic electroluminescent device according to the invention does not comprise a separate hole-injection layer and/or hole-transport layer and/or hole-blocking layer and/or electron-transport layer, i.e. the emitting layer is directly adjacent to the hole-injection layer or the anode, and/or the emitting layer is directly adjacent to the electron-transport layer or the electron-injection layer or the cathode, as described, for example, in WO 2005/053051 . It is furthermore possible to use a metal complex which is identical or similar to the metal complex in the emitting layer as hole-transport or hole- injection material directly adjacent to the emitting layer, as described, for example, in WO 2009/030981 .

It is furthermore possible to employ the compounds according to the invention in a hole-blocking or electron-transport layer. This applies, in particular, to compounds according to the invention which do not have a carbazole structure. These may preferably also be substituted by one or more further electron- transporting groups, for example benzimidazole groups.

In the further layers of the organic electroluminescent device according to the invention, it is possible to use all materials as usually employed in accordance with the prior art. The person skilled in the art will therefore be able, without inventive step, to employ all materials known for organic electroluminescent devices in combination with the compounds of the formula (1 ) or in accordance with the preferred embodiments.

For example, the compound according to the invention can also be used as a matrix for semiconducting light-emitting nanoparticles. In the context of the present invention, the term "nano" denotes a size in the range from 0.1 to 999 nm, preferably from 1 to 150 nm. In a preferred embodiment, the semiconducting light-emitting nano-particle is a quantum material ("Quantum sized material"). The term "quantum material" in the sense of the present invention refers to the size of the semiconductor material itself without further connections or a further surface modification, which shows the so-called quantum confinement effect, as for example in ISBN: 978-3-662-44822-9. In one embodiment of the invention, the total size of the quantum material is in the range from 1 to 100 nm, more preferably from 1 to 30 nm and particularly preferably from 5 to 15 nm. In this case, the core of the semiconducting light-emitting nano-particle can vary. Suitable examples are CdS, CdSe, CdTe, ZnS, ZnSe, ZnSeS, ZnTe, ZnO, GaAs, GaP, GaSb, HgS, HgSe, HgSe, HgTe, InAs, InP, InPS, InPZnS, InPZn, InPGa, InSb, AIAs , AIP, AlSb, CU2S, Cu2Se, CulnS2, CulnSe2, Cu2(ZnSn)S ₄ , Cu2(lnGa) S ₄ , T1O2, or a combination of said materials. In a preferred embodiment, the core of the semiconductive light-emitting particle contains one or more elements of group 13 and one or more elements of group 15 of the periodic system of the elements, for example GaAs, GaP, GaSb, InAs, InP, InPS, InPZnS, InPZn, InPGa, InSb, AIAs, AIP, AlSb, CulnS2, CulnSe2, Cu2(lnGa)S ₄ or a combination of the mentioned materials. Particularly preferably, the core contains In- and P- atoms, z. InP, InPS, InPZnS, InPZn or InPGa. In a further embodiment of the invention, the nanoparticle contains one or more shell layers, which comprise a first element from the group 12, 13 or 14 of the periodic table and a second element from the group 15 or 16 of the periodic table. Preferably, all shell layers contain a first element from the group 12, 13 or 14 of the periodic system and a second element from the group 15 or 16 of the periodic system. In a preferred embodiment of the invention, at least one of the shell layers contains a first element from the group 12 and a second element from the group 16 of the periodic table, for example CdS, CdZnS, ZnS, ZnSe, ZnSSe, ZnSSeTe, CdS/ZnS, ZnSe/ZnS or ZnS/ZnSe. Particularly preferably, all shell layers contain a first element from the group 12 and a second element from the group 16 of the periodic table. Preference is furthermore given to an organic electroluminescent device, characterised in that one or more layers are applied by means of a sublimation process, in which the materials are vapour-deposited in vacuum sublimation units at an initial pressure of less than 10 ⁵ mbar, preferably less than 10 ⁶ mbar. However, it is also possible for the initial pressure to be even lower or higher, for example less than 10 ⁷ mbar.

Preference is likewise given to an organic electroluminescent device, characterised in that one or more layers are applied by means of the OVPD (organic vapour phase deposition) process or with the aid of carrier-gas sublimation, in which the materials are applied at a pressure between 10 ⁵ mbar and 1 bar. A special case of this process is the OVJP (organic vapour jet printing) process, in which the materials are applied directly through a nozzle and thus structured (for example M. S. Arnold et al., Appl. Phys. Lett. 2008, 92, 053301 ).

Preference is furthermore given to an organic electroluminescent device, characterised in that one or more layers are produced from solution, such as, for example, by spin coating, or by means of any desired printing process, such as, for example, ink-jet printing, LITI (light induced thermal imaging, thermal transfer printing), screen printing, flexographic printing, offset printing or nozzle printing. Soluble compounds, which are obtained, for example, by suitable substitution, are necessary for this purpose.

Also possible are hybrid processes, in which, for example, one or more layers are applied from solution and one or more further layers are applied by vapour deposition. Thus, it is possible, for example, to apply the emitting layer from solution and to apply the electron-transport layer by vapour deposition.

These processes are generally known to the person skilled in the art and can be applied by him without inventive step to organic electroluminescent devices comprising the compounds according to the invention. The compounds according to the invention generally have very good properties on use in organic electroluminescent devices. In particular, the lifetime on use of the compounds according to the invention in organic electroluminescent devices is significantly better compared with similar compounds in accordance with the prior art. The other properties of the organic electroluminescent device, in particular the efficiency and the voltage, are likewise better or at least comparable. Furthermore, the compounds have a high glass transition temperature and high thermal stability.

The invention will now be explained in greater detail by the following examples, without wishing to restrict it thereby.

A) Syntheses Examples

The following syntheses are carried out, unless indicated otherwise, under a protective-gas atmosphere in dried solvents. The solvents and reagents can be purchased, for example, from Sigma-ALDRICH or ABCR. The corresponding CAS numbers are also indicated in each case from the compounds known from the literature.

Example a:

6-(3-Triphenylen-2-yl-phenyl)-6H-benzo[c][2,6]naphthyridin-5 -one

19.6 g (100 mmol) of benzo[c]-2,6-naphthyridinone, 51.6 g (120 mmol) of 2- (3- iodo-phenyl)-triphenylene and 2.3 g (20 mmol) of L-proline are dissolved in 100 ml_ of DMF and stirred at 150 ° C for 30 h. The solution is diluted with water, extracted with ethyl acetate twice, the combined organic phases dried over Na ₂ S0 ₄ and concentrated by rotary evaporation. The residue is purified by chromatography (EtOAc / hexane: 2/3). The residue is recrystallized from toluene and from dichloromethane / toluene and finally sublimed under high vacuum. The yield is 39 g (78 mmol) 66% of theory.

The following compounds are obtained analogously:

Example b: 5-(4-Brom-phenyl)-5H-phenanthridin-6-one

6.0 g (22.2 mmol) of 5-phenyl-5H-phenanthridin-6-one are initially put in 150 ml_ of DMF. A solution of 4 g (22.5 mmol) of NBS is then added dropwise in 100 ml_ of DMF at room temperature, with exclusion of light. The mixture is further stirred during 4 h at room temperature. Then, the mixture is mixed with 150 ml_ of water and extracted with CFI2CI2. The organic phase is dried over MgS04 and the solvents are removed in vacuo. The product is stirred with hot hexane and filtered. Yield: 7.4 g (21 mmol), 80% of theory.

The following compounds are obtained analogously:

Analogously, the following compounds are obtained with 2 equivalents of NBS in chloroform as solvent:

Example c: 5-(4-Triphenylen-2-yl-phenyl)-5H-phenanthridin-6-one

29.9 g (1 10.0 mmol) of triphenylene-2-boronic acid, 38 g (1 10.0 mmol) of 5- (4- bromo-phenyl)-5H-phenanthridin-6-one and 44.6 g (210.0 mmol) of tripotassium phosphate are suspended in 500 ml_ of toluene, 500 ml_ of dioxane and 500 ml_ of water. Then, 913 mg (3.0 mmol) of tri-o-tolyl-phosphine and subsequently 1 12 mg (0.5 mmol) of palladium(ll)acetate are added to this suspension, and the reaction mixture is heated under reflux for 16 h. After cooling, the organic phase is collected, filtered through silica gel, washed three times with 200 ml_ of water and then concentrated to dryness. The residue is recrystallized from toluene and from dichloromethane / isopropanol and finally sublimed under high vacuum, purity is 99.9%. The yield is 43 g (86 mmol), corresponding to 80% of theory.

The following compounds are obtained analogously:

A) Fabrication of OLEDs

The following examples V1 and E1 (see Table 1 ) show data of OLEDs. Substrate pre-treatment of examples V1 - E1 :

Glass plates with structured ITO (50 nm, indium tin oxide) form the substrates on which the OLEDs are processed. Before evaporation of the OLED materials, the substrates are cleaned in a wet process (using filtered deionized water and the detergent“Extran” of Merck KGaA). Glass substrates are then dried for 15 minutes at 170°C.

Subsequently the clean and dry substrates are exposed to a oxygen and subsequently to an Argon plasma.

The OLEDs have in principle the following layer structure: substrate / hole- transport layer (HTL) / optional interlayer (IL) / electron-blocking layer (EBL) / emission layer (EML) / optional hole-blocking layer (HBL) / electron-transport layer (ETL) / optional electron-injection layer (EIL) and finally a cathode. The cathode is formed by an aluminium layer with a thickness of 100 nm. The exact layer structure is denoted in Table 1 (ITO and Aluminium layers are omitted for clarity). The materials used for the OLED fabrication are presented in Table 2.

All materials are applied by thermal vapour deposition in a vacuum chamber.

The emission layer here always consists of at least one matrix material (host material) and an emitting dopant (emitter), which is admixed with the matrix material or matrix materials in a certain proportion by volume by co-evaporation. An expression such as CbzT1 :SdT1 :TEG1 (41 %:41 %:18%) here means that material CbzT1 is present in the layer in a proportion by volume of 41 %, SdT1 is present in the layer in a proportion of 41 % and TEG1 is present in the layer in a proportion of 18%. Analogously, the electron-transport layer may also consist of a mixture of two materials.

The OLEDs are characterized by standard methods. For this purpose, the electroluminescence spectra and the lifetime are determined. The electroluminescent spectra are determined at a brightness of 1000 cd/m ² and the corresponding CIE 1931 x and y color coordinates are determined.

Lifetime LT is defined as the time in hours (h), after which the starting brightness at constant current density jo _, is reduced to a certain level L1 in % of the starting brightness.

Here L1 =80% means, that the given lifetime LT corresponds to the time after which the brightness is reduced to 80% of its starting value.

Use of inventive compounds as host material in phosphorescent OLEDs

The inventive compounds can be used for example in the emission layer (EML) of a phosphorescent green OLED. The inventive combination of the compound CbzT1 with one of the compound EG1 to EG5 is used as matrix material in the emission layer.

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

Use of inventive compounds as host material in phosphorescent OLEDs

By using the compounds according to the state of the art like in example V1 with high emitter concentrations in the EML of e.g. 18%, good color coordinates with x/y in the range of 0.33/0.63 can be reached.

Nevertheless, the lifetime of such devices is not very high.

A substantial improvement of the lifetime by 25-30% versus the state of the art like in example V1 at similar color coordinates, can be reached for example by using the inventive combination of CbzT1 and one of the compound EG1 to EG5 and similar emitter concentrations (e.g. 18%) in the emission layer like in example E1. Table 1 : Structure of the OLEDs

Table 2: Chemical structures of the materials used in the OLEDs