Spiro dihydroacridine derivatives and the use thereof as materials for organic electroluminescence devices

This application is a national stage application (under 35 U.S.C. § 371) of PCT/EP2012/004362, filed Oct. 18, 2012, which claims benefit of European Application No. 11009127.9, filed Nov. 17, 2011, both of which are incorporated herein by reference in their entirely.

The present invention relates to materials for use in electronic devices, in particular in organic electroluminescent devices, and to electronic devices, in particular organic electroluminescent devices, comprising these materials.

The structure of organic electroluminescent devices (OLEDs) in which organic semiconductors are employed as functional materials is described, for example, in U.S. Pat. Nos. 4,539,507, 5,151,629, EP 0676461 and WO 98/27136. The emitting materials employed here are increasingly organometallic complexes which exhibit phosphorescence instead of fluorescence. For quantum-mechanical reasons, an up to four-fold energy and power efficiency is possible using organometallic compounds as phosphorescence emitters. In general, however, there is still a need for improvement, for example with respect to efficiency, operating voltage and lifetime, in the case of OLEDs, in particular also in the case of OLEDs which exhibit triplet emission (phosphorescence). In addition, it is desirable that the materials used can be synthesised in high yield and purity.

The properties of phosphorescent OLEDs are determined not only by the triplet emitters employed. In particular, the other materials used, such as matrix materials, hole-blocking materials, electron-transport materials, hole-transport materials and electron- or exciton-blocking materials, are also of particular importance here. Improvements in these materials can thus also result in significant improvements in the OLED properties. For fluorescent OLEDs too, there is still a need for improvement in these materials and for emitters and matrix materials.

In accordance with the prior art, use is made, inter alia, of carbazole derivatives, for example in accordance with 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, or dihydroacridine derivatives, for example in accordance with US 2010/0019658, as matrix materials for phosphorescent emitters in organic electroluminescent devices. Further improvements are desirable here, likewise in relation to the efficiency, the lifetime and the thermal stability of the materials.

The object of the present invention is the provision of compounds which are suitable for use in a fluorescent or phosphorescent OLED, in particular as matrix material or as hole-transport/electron-blocking material or exciton-blocking material, but also as hole-blocking material, matrix for fluorescent emitters or as fluorescent emitter. It is a further object of the present invention to provide further organic semiconductors for organic electroluminescent devices in order to facilitate a greater choice in the production of OLEDs for the person skilled in the art.

Surprisingly, it has been found that certain compounds, described in greater detail below, achieve this object and result in improvements in the organic electroluminescent device. The improvements here relate, in particular, to the lifetime, the efficiency and/or the operating voltage. 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 relates to a compound of the formula (1), (2) or (3)

where the following applies to the symbols and indices used:

Y is on each occurrence, identically or differently, O, S, Se, BR 1 , C(R 1 ) 2 , Si(R 1 ) 2 , PR 1 , P(═O)R 1 , C(R 1 ) 2 —C(R 1 ) 2 , CR 1 ═CR 1 or a benzene group which is linked via the ortho-positions and which may be substituted by one or more radicals R 1 ; X is on each occurrence, identically or differently, CR 2 or N; or two adjacent X stand for S, O or NR 2 , so that a five-membered ring arises; or two adjacent X stand for a group of the following formula (4) or (5),

where ^ indicates the corresponding adjacent groups X in the formula (1), (2) or (3);

X here stands for C if a group Ar or L is bonded to this group X in formula (2) or (3);

V is on each occurrence, identically or differently, C(R 2 ) 2 , NR 2 , O or S;

Z is on each occurrence, identically or differently, CR 2 or N;

Ar is on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may be substituted by one or more radicals R 3 ; the group Ar and the adjacent group X, which in this case stands for C, may also be bridged to one another here by a single bond or a divalent group selected from C(R 3 ) 2 , NR 3 , O or S;

L is on each occurrence, identically or differently, a single bond or a divalent group;

R 1 , R 2 , R 3 is selected on each occurrence, identically or differently, from the group consisting of H, D, F, Cl, Br, I, CN, NO 2 , N(Ar 1 ) 2 , N(R 4 ) 2 , C(═O)Ar 1 , C(═O)R 4 , P(═O)(Ar 1 ) 2 , a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms, each of which may be substituted by one or more radicals R 4 , where one or more non-adjacent CH 2 groups may be replaced by R 4 C═CR 4 , C≡C, Si(R 4 ) 2 , C═O, C═S, C═NR 4 , P(═O)(R 4 ), SO, SO 2 , NR 4 , O, S or CONR 4 and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO 2 , 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 4 , an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R 4 , where two or more adjacent substituents R 1 or R 3 may optionally form a monocyclic or polycyclic, aliphatic ring system or R 2 may form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system, which may be substituted by one or more radicals R 4 ;

R 4 is selected on each occurrence, identically or differently, from the group consisting of H, D, F, Cl, Br, I, CN, NO 2 , N(Ar 1 ) 2 , N(R 5 ) 2 , C(═O)Ar 1 , C(═O)R 5 , P(═O)(Ar 1 ) 2 , a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms, each of which may be substituted by one or more radicals R 5 , where one or more non-adjacent CH 2 groups may be replaced by R 5 C═CR 5 , C≡C, Si(R 5 ) 2 , C═O, C═S, C═NR 5 , P(═O)(R 5 ), SO, SO 2 , NR 5 , O, S or CONR 5 and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO 2 , 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 5 , an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R 5 , or a combination of these systems, where two or more adjacent substituents R 4 may optionally form a monocyclic or polycyclic, aliphatic ring system, which may be substituted by one or more radicals R 5 ;

Ar 1 is on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5-30 aromatic ring atoms, which may be substituted by one or more non-aromatic radicals R 5 ; two radicals Ar 1 which are bonded to the same N atom or P atom may also be bridged to one another here by a single bond or a bridge selected from N(R 5 ), C(R 5 ) 2 , O or S;

R 5 is selected on each occurrence, identically or differently, from the group consisting of H, D, F, CN, an aliphatic hydrocarbon radical having 1 to 20 C atoms, an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, in which one or more H atoms may be replaced by D, F, Cl, Br, I or CN, where two or more adjacent substituents R 5 may form a mono- or polycyclic, aliphatic ring system with one another;

m is on each occurrence, identically or differently, 0 or 1;

n is 0, 1, 2, 3, 4 or 5;

p is 0 or 1.

An aryl group in the sense of this invention contains 6 to 60 C atoms; a heteroaryl group in the sense of this invention contains 2 to 60 C atoms and at least one heteroatom, with the proviso that the sum of C atoms and heteroatoms is at least 5. The heteroatoms are preferably selected from N, O and/or S. 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, thiophene, etc., or a condensed (annellated) aryl or heteroaryl group, for example naphthalene, anthracene, phenanthrene, quinoline, isoquinoline, etc. Aromatic groups which are linked to one another by a single bond, such as, for example, biphenyl, are, by contrast, not referred to as aryl or heteroaryl group, but instead as aromatic ring system.

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 2 to 60 C atoms and at least one heteroatom in the ring system, with the proviso that the sum of C atoms and heteroatoms is at least 5. The heteroatoms are preferably selected from N, O and/or S. For the purposes of this invention, an aromatic or heteroaromatic ring system 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, such as, for example, a C, N or O atom. Thus, for example, systems such as fluorene, 9,9′-spirobifluorene, 9,9-diarylfluorene, triarylamine, diaryl ether, stilbene, etc., are also intended to be taken to be aromatic ring systems for the purposes of this invention, as are systems in which two or more aryl groups are connected, for example, by a short alkyl group.

For the purposes of the present invention, an aliphatic hydrocarbon radical or an alkyl group or an alkenyl or alkynyl group, which may contain 1 to 40 C atoms and in which, in addition, individual H atoms or CH 2 groups may be substituted by the groups mentioned above, 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, neopentyl, cyclopentyl, n-hexyl, neohexyl, cyclohexyl, 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, heptynyl or octynyl. An alkoxy 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, cycloheptyloxy, n-octyloxy, cyclooctyloxy, 2-ethylhexyloxy, pentafluoroethoxy and 2,2,2-trifluoroethoxy. A thioalkyl group having 1 to 40 C atoms is taken to mean, in particular, 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. In general, alkyl, alkoxy or thioalkyl groups in accordance with the present invention may be straight-chain, branched or cyclic, where one or more non-adjacent CH 2 groups may be replaced by the groups mentioned above; furthermore, one or more H atoms may also be replaced by D, F, Cl, Br, I, CN or NO 2 , preferably F, Cl or CN, further preferably F or CN, particularly preferably CN.

An aromatic or heteroaromatic ring system having 5-60 aromatic ring atoms, which may also in each case be substituted by the radicals R 2 mentioned above or a hydrocarbon radical and which may be linked via any desired positions on the aromatic or heteroaromatic ring system, is taken to mean, in particular, groups derived from benzene, naphthalene, anthracene, benzanthracene, phenanthrene, pyrene, chrysene, perylene, fluoranthene, naphthacene, pentacene, benzopyrene, biphenyl, biphenylene, terphenyl, triphenylene, fluorene, spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- or trans-indenofluorene, cis- or trans-indenocarbazole, cis- or trans-indolocarbazole, truxene, isotruxene, spirotruxene, spiroisotruxene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothiophene, 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, benzothiazole, pyridazine, hexaazatriphenylene, 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, benzocarboline, 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 benzothiadiazole or groups derived from combinations of these systems.

As described above, the group Ar and an adjacent group X may also be bridged to one another. An “adjacent group X” here is taken to mean a group X which is separated from the group Ar by a nitrogen atom and a carbon atom, as depicted diagrammatically below, where this group X stands for C if this X and the group Ar are bridged:

The ring formation is depicted below by way of example for compounds of the formula (1) where n=0, where the ring formation can take place entirely analogously to the other compounds according to the invention:

where E stands for a single bond, C(R 3 ) 2 , NR 3 , O or S and the other symbols and indices used have the meanings given above.

In a preferred embodiment of the invention, Y stands, identically or differently on each occurrence, for O or C(R 1 ) 2 , particularly preferably for O.

Furthermore preferably, all groups Y are selected identically.

In a further preferred embodiment of the invention, X stands, identically or differently on each occurrence, for CR 2 or N, where a maximum of one group X per ring stands for N; or two adjacent groups X stand for a group of the formula (4) or (5), in particular formula (5), where Z stands, identically or differently on each occurrence, for CR 2 and V stands, identically or differently on each occurrence, for NR 2 or C(R 2 ) 2 .

X particularly preferably stands, identically or differently on each occurrence, for CR 2 .

Preference is furthermore given to compounds of the formula (1) mentioned above and the following compounds (2a) or (3a),

Particular preference is given to compounds of the formula (1 mentioned above), in particular where n=0.

In a preferred embodiment of the invention, the group L stands, identically or differently on each occurrence, for a straight-chain alkylene, alkylidene, alkyleneoxy or thioalkyleneoxy group having 1 to 10 C atoms or a branched or cyclic alkylene, alkylidene, alkyleneoxy or thioalkyleneoxy group having 3 to 40 C atoms or an alkenylene or alkynylene group having 2 to 40 C atoms, which may be substituted by in each case one or more radicals R 4 , where one or more non-adjacent CH 2 groups may be replaced by —R 4 C═CR 4 —, —C≡C—, Si(R 4 ) 2 , C═O, C═NR 4 , P(═O)R 4 , S═O, SO 2 , —O—, —S— or —CONR 4 — and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO 2 , or P(R 4 ), P(═O)(R 4 ), N(Ar 1 ); or L is a single bond.

In a particularly preferred embodiment of the invention, the group L stands for a single bond.

Preferred embodiments of the compounds of the formula (1), (2) and (3) are the compounds of the following formulae (6), (7) and (8),

where the symbols and indices used have the meanings given above and Y preferably stands for O.

Furthermore, groups of the formula (4) or (5) may be condensed on, as depicted below by way of example by the formulae (9), (10), (11) and (12) with condensed-on groups of the formula (5),

Particular preference is given to the compounds of the following formulae (6a) to (12a).

where the symbols and indices used have the meanings given above and Y preferably stands for O.

Very particular preference is given to the compounds of the following formulae (6b) to (12b).

where the symbols and indices used have the meanings given above and Y preferably stands for O.

Particular preference is given to the compounds of the formula (6b) in which the index n=0 or 1.

In a preferred embodiment of the invention, R 1 , R 2 and R 3 in the formulae mentioned above are selected, identically or differently on each occurrence, from the group consisting of H, D, F, Cl, Br, CN, N(Ar 1 ) 2 , C(═O)Ar 1 , a straight-chain alkyl or alkoxy group having 1 to 10 C atoms, a branched or cyclic alkyl or alkoxy group having 3 to 10 C atoms, an alkenyl or alkynyl group having 2 to 10 C atoms, each of which may be substituted by one or more radicals R 4 , where one or more non-adjacent CH 2 groups may be replaced by O and where one or more H atoms may be replaced by D or F, and an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which may in each case be substituted by one or more radicals R 4 .

In a particularly preferred embodiment of the invention, R 1 , R 2 and R 3 in the formulae mentioned above are selected, identically or differently on each occurrence, from the group consisting of H, D, F, Cl, Br, CN, a straight-chain alkyl group having 1 to 5 C atoms, a branched or cyclic alkyl group having 3 to 10 C atoms, where one or more H atoms may be replaced by D or F, and an aromatic or heteroaromatic ring system having 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R 4 .

R 2 preferably does not encompass a heteroaryl group having 5 ring atoms, an alkenyl group or an alkynyl group.

R 2 is preferably selected, identically or differently on each occurrence, from the group consisting of H, D, F, Cl, Br, CN, a straight-chain alkyl group having 1 to 5 C atoms, a branched or cyclic alkyl group having 3 to 10 C atoms, where one or more H atoms may be replaced by D or F, and an aromatic ring system having 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R 4 , where R 4 is selected on each occurrence, identically or differently, from the group consisting of H, D, F, Cl, Br, I, CN, NO 2 , N(Ar 1 ) 2 , N(R 5 ) 2 , C(═O)Ar 1 , C(═O)R 5 , P(═O)(Ar 1 ) 2 , a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 5 C atoms, a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 10 C atoms, where one or more H atoms may be replaced by D, F, Cl, Br or CN, and an aromatic or heteroaromatic ring system having 5 to 18 aromatic ring atoms, which may in each case be substituted by one or more radicals R 5 .

For compounds which are processed by vacuum evaporation, the alkyl groups preferably have not more than five C atoms, particularly preferably not more than 4 C atoms, very particularly preferably not more than 1 C atom. For compounds which are processed from solution, suitable compounds are also those which are substituted by alkyl groups, in particular branched alkyl groups, having up to 10 C atoms or which are substituted by oligoarylene groups, for example ortho-, meta-, para- or branched terphenyl or quaterphenyl groups.

Preferred groups Ar are selected from aromatic or heteroaromatic ring systems having 5 to 24 aromatic ring atoms, which may in each case be substituted by one or more radicals R 3 . Particularly preferred groups Ar are selected from benzene, ortho-, meta- or para-biphenyl, ortho-, meta-, para- or branched terphenyl, ortho-, meta- para- or branched quaterphenyl, 1- or 2-naphthyl, pyrrole, furan, thiophene, indole, benzofuran, benzothiophene, carbazole, dibenzofuran, dibenzothiophene, pyridine, pyrimidine, pyrazine, pyridazine, triazine, anthracene, phenanthrene, pyrene, benzanthracene or combinations of two or three of these groups, each of which may be substituted by one or more radicals R 3 .

If R 1 , R 2 and R 3 stand for an aromatic or heteroaromatic ring system, this is preferably selected, identically or differently on each occurrence, from the same groups as indicated above as preferred groups for Ar. If Y stands for BR 1 , R 1 then preferably stands for an aryl or heteroaryl group which is substituted in at least one ortho-position and preferably in both ortho-positions, for example for a xylyl or mesityl group.

If the compounds of the formula (1), (2) or (3) or the preferred embodiments are used as electron-transport material, it is preferred for the group Y to stand for BR 1 or P(═O)(R 1 ) and/or for at least one of the radicals R 1 , R 2 and/or Ar to stand for an electron-deficient heteroaromatic ring system. In accordance with the invention, electron-deficient heteroaromatic rings are five-membered heteroaromatic rings having at least two heteroatoms or six-membered heteroaromatic rings, onto which in each case one or more aromatic or heteroaromatic groups may also be condensed, for example substituted or unsubstituted imidazoles, pyrazoles, thiazoles, oxazoles, oxadiazoles, triazoles, pyridines, pyrazines, pyrimidines, pyridazines, triazines, benzimidazoles, etc., in particular those as shown below.

If the compound according to the invention is employed as matrix material for a phosphorescent emitter or as electron-transport material, it is preferred for at least one substituent R 1 , R 2 and/or R 3 or a monovalent group Ar to be an electron-deficient group, in particular selected from structures of the following formulae (13) to (16) for R 1 to R 3 or the formulae (13), (15) or (16) for Ar,

and/or at least one divalent or trivalent group Ar preferably stands for a group of the following formulae (17) to (19),

where R 3 , R 4 and m have the meaning given above, * indicates the position of the bonding of the group of the formula (13) to (19) and furthermore:

A is on each occurrence, identically or differently, CR 4 or N, with the proviso that one, two or three groups A stand for N; Ar 2 is, identically or differently on each occurrence, a divalent aromatic or heteroaromatic ring system having 5 to 16 C atoms, which may be substituted by one or more radicals R 4 ;

where R 4 is to be replaced by R 3 if the groups of the formulae (13), (15) and (16) stand for Ar and in the cases of the formulae (17) to (19).

In a particularly preferred embodiment of the invention, at least one substituent R 1 , R 2 , R 3 or Ar stands for a group of the formula (13) mentioned above, and/or at least one group Ar stands for a group of the formulae (17) to (19) mentioned above, where in each case two or three symbols A stand for N and the other symbols A stand for CR 4 , where R 3 is to be replaced by R 4 if the groups of the formulae (13), (15) and (16) stand for Ar and in the cases of the formulae (17) to (19).

Particularly preferred groups R 1 , R 2 , R 3 or Ar are therefore the groups of the following formulae (20) to (26), and particularly preferred groups Ar are the groups of the following formulae (27) to (34),

where the symbols and indices used have the meanings given above, and where R 4 is to be replaced by R 3 if the groups of the formulae (20) to (26) stand for Ar and in the cases of the formulae (27) to (34).

If R 1 , R 2 , R 3 or Ar stands for a group of the formula (20), R 3 or R 4 in this group then preferably stands for an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms, which may be substituted by one or more radicals R 5 , in particular for phenyl, ortho-, meta- or para-biphenyl, ortho-, meta-, para- or branched terphenyl or ortho-, meta-, para- or branched quaterphenyl.

If R 1 , R 2 , R 3 or Ar stands for a group of the formula (21) to (26), R 3 or R 4 in these groups then preferably stands, identically or differently on each occurrence, for H, D or an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms, which may be substituted by one or more radicals R 5 , in particular for H or phenyl, ortho-, meta- or para-biphenyl, ortho-, meta-, para- or branched terphenyl or ortho-, meta-, para- or branched quaterphenyl.

If Ar stands for a group of the formula (27) to (34), R 3 in these groups then preferably stands, identically or differently on each occurrence, for H, D or an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms, which may be substituted by one or more radicals R 5 , in particular for H or phenyl, ortho-, meta- or para-biphenyl, ortho-, meta-, para- or branched terphenyl or ortho-, meta-, para- or branched quaterphenyl.

If the compound according to the invention is employed as matrix material for a phosphorescent emitter, as hole-transport material or as electron- or exciton-blocking material, at least one substituent R 1 , R 2 , R 3 or Ar is preferably selected from the group consisting of triarylamine derivatives, carbazole derivatives, indenocarbazole derivatives, indolocarbazole derivatives, azacarbazole derivatives, indole derivatives, furan derivatives, benzofuran derivatives, dibenzofuran derivatives, thiophene derivatives, benzothiophene derivatives or dibenzothiophene derivatives, each of which may be substituted by one or more radicals R 3 or R 4 , or at least one substituent R 1 , R 2 or R 3 stands for —NAr 2 . These groups are preferably selected from the groups of the following formulae (35) to (49),

where the symbols used have the meanings given above and furthermore:

E is selected from the group consisting of C(R 4 ) 2 , NR 4 , O or S;

G is selected from the group consisting of NR 4 , O or S, and

R 4 is to be replaced by R 3 if the groups of the formulae (35) to (49) stand for Ar.

In a further preferred embodiment of the invention, the symbols R 1 , R 2 and R 3 which do not stand for a group of the formulae (13) to (49) mentioned above in the compounds according to the invention stand for H or D.

The preferred embodiments mentioned above can be combined with one another as desired. In a particularly preferred embodiment of the invention, the preferences mentioned above occur simultaneously.

If the compounds of the formula (1), (2) or (3) or the preferred embodiments are used as matrix material for a phosphorescent emitter, it is preferred for the compound to contain no condensed aryl or heteroaryl groups in which more than two six-membered rings are condensed directly onto one another. In particular, it is preferred for the radicals R 1 , R 2 , R 3 and Ar to contain no condensed aryl or heteroaryl group in which two or more six-membered rings are condensed directly onto one another, and for two adjacent groups X not to stand for a group of the formula (4). The compound of the formula (1), (2) or (3) particularly preferably contains absolutely no condensed aryl or heteroaryl groups in which six-membered rings are condensed directly onto one another.

If the compounds of the formula (1), (2) or (3) or the preferred embodiments are used as matrix material for a fluorescent emitter or as fluorescent emitter, it is preferred for at least one of the radicals R 1 , R 2 and/or R 3 to contain a group which is selected from naphthalene, anthracene, phenanthrene, pyrene and/or benzanthracene, each of which may also be substituted by the groups mentioned above, and/or for two adjacent groups X at least on one of the aromatic rings to stand for a group of the formula (4).

If the compounds of the formula (1), (2) or (3) or the preferred embodiments are employed as hole-transport material in a hole-transporting, hole-injecting or another layer, it is preferred for at least one of the radicals R 1 , R 2 and/or R 3 to contain a group which is selected from aromatic ring systems having 6 to 24 aromatic ring atoms. In this case, it is furthermore preferred for Y to be selected on each occurrence, identically or differently, from O, S and C(R 1 ) 2 , and particularly preferably to be O.

Examples of preferred compounds of the embodiments mentioned above are the compounds of the following structures.

The compounds according to the invention can be prepared by the routes outlined in Scheme 1 to 4.

Starting from a 1,2-dihalogen-substituted aromatic or heteroaromatic compound, a Buchwald or Ullmann coupling to a secondary amine results in an o-halogen-functionalised tertiary amine. This can be coupled, after metallation, to a heterocyclic ketone to give a triarylmethanol, which cyclises under acid catalysis to give the spiro compound (A) according to the invention (Scheme 1). The spiro compound (A) can be mono- or dibrominated (optionally also tri-, tetra-, etc., brominated with involvement of further active positions) regioselectively—preferably in the p-position to the N atom, the bromides (B) and (C) formed in this way can subsequently be reacted further by methods familiar to the person skilled in the art (C—C coupling, such as Suzuki, Negishi, Yamamoto, Grignard-Cross, Stille, Heck coupling, etc.; C—N coupling, such as Buchwald or Ullmann coupling, silylation, phosphanylation, boranylation, polycondensation, etc.). Besides regioselective bromination, reaction with other electrophiles, for example in Friedel-Crafts alkylation or acylation, sulfonation, nitration, etc., is of course also possible.

If the secondary amine carries a protecting group PG (for example N-acyl, N-Boc, N-benzyl, N-sulfenyl, N-silyl, etc.) at the beginning of the sequence, the secondary spiroamine (E) can be obtained after build-up of the spiro compound (D) by removal of the protecting group and can be reacted further by C—N coupling methods familiar to the person skilled in the art (Buchwald or Ullmann coupling, etc.) (Scheme 2). Compounds according to the invention containing a plurality of units (E) are accessible by this route by coupling to polyfunctionalised aromatic compounds. These can then be functionalised further via the route described in Scheme 1 of reaction with electrophiles.

The bromide (B) is additionally suitable for the build-up of extended condensed heterocyclic compounds according to the invention (Scheme 3). Suzuki coupling of (B) to o-YH-functionalised aromatic or heteroaromatic compounds results in (F), which can be cyclised to give (G). Analogously, a Buchwald or Ullmann coupling of (B) results in (H), which can be cyclised to give (I).

The spiroamine (E) is furthermore suitable for the build-up of extended condensed heterocyclic compounds (K) according to the invention (Scheme 4). C—N coupling of (E) to o-halogen-functionalised aromatic compounds which carry YH functions and subsequent cyclisation of the intermediate (J) results in extended heterocyclic compounds (K).

The reactions shown in Scheme 3 and 4 are of course also possible analogously with the dibromide (C). In this way, condensed heterocyclic compounds containing fluorenes, dibenzofurans, thiodibenzofurans, carbazoles, etc. can be obtained by methods familiar to the person skilled in the art.

The present invention furthermore relates to a process for the preparation of a compound of the formula (1), (2) or (3), comprising the reaction steps:

a) build-up of the halogenated skeleton; and b) introduction of substituents via a transition-metal-catalysed coupling reaction.

The compounds according to the invention described above, in particular compounds which are substituted by reactive leaving groups, such as bromine, iodine, chlorine, boronic acid or boronic acid ester, or by reactive, polymerisable groups, such as olefins, styrenes, acrylates or oxetanes, can be used as monomers for the generation of corresponding oligomers, dendrimers or polymers. The oligomerisation or polymerisation here preferably takes place via the halogen functionality or the boronic acid functionality or via the polymerisable group. It is furthermore possible to crosslink the polymers via groups of this type. The compounds and polymers according to the invention can be employed as crosslinked or uncrosslinked layer.

The invention therefore furthermore relates to oligomers, polymers or dendrimers containing one or more of the compounds according to the invention indicated above, where one or more bonds from the compound according to the invention to the polymer, oligomer or dendrimer are present at one or more positions instead of substituents. Depending on the linking of the compound according to the invention, this forms a side chain of the oligomer or polymer or is linked in the main chain or forms the core of a dendrimer. The polymers, oligomers or dendrimers may be conjugated, partially conjugated or non-conjugated. The oligomers or polymers may be linear, branched or dendritic. The same preferences as described above apply to the recurring units of the compounds according to the invention in oligomers, dendrimers and polymers.

For the preparation of the oligomers or polymers, the monomers according to the invention are homopolymerised or copolymerised with further monomers. Preference is given to homopolymers or copolymers in which the units of the formula (1) or the preferred embodiments indicated above are present to the extent of 0.01 to 99.9 mol %, preferably 5 to 90 mol %, particularly preferably 20 to 80 mol %. Suitable and preferred comonomers which form the polymer backbone are selected from fluorenes (for example in accordance with EP 842208 or WO 2000/22026), spirobifluorenes (for example in accordance with EP 707020, EP 894107 or WO 2006/061181), para-phenylenes (for example in accordance with WO 92/18552), carbazoles (for example in accordance with WO 2004/070772 or WO 2004/113468), thiophenes (for example in accordance with EP 1028136), dihydrophenanthrenes (for example in accordance with WO 2005/014689), cis- and trans-indenofluorenes (for example in accordance with WO 2004/041901 or WO 2004/113412), ketones (for example in accordance with WO 2005/040302), phenanthrenes (for example in accordance with WO 2005/104264 or WO 2007/017066) or also a plurality of these units. The polymers, oligomers and dendrimers may also contain further units, for example hole-transport units, in particular those based on triarylamines, and/or electron-transport units. In addition, the polymers may contain triplet emitters, either copolymerised or mixed in as a blend. In particular, the combination of the oligomers, polymers or dendrimers according to the invention with triplet emitters leads to particularly good results.

Furthermore, the compounds according to the invention may also be functionalised further and thus converted into extended structures. An example which may be mentioned here is the reaction with arylboronic acids by the Suzuki method or with primary or secondary amines by the Hartwig-Buchwald method. Thus, the compounds according to the invention can also be bonded directly to phosphorescent metal complexes or also to other metal complexes.

The compounds according to the invention are suitable for use in an electronic device, in particular in an organic electroluminescent device.

The present invention therefore furthermore relates to the use of a compound according to the invention in an electronic device, in particular in an organic electroluminescent device.

The present invention still furthermore relates to an electronic device comprising at least one compound according to the invention.

An electronic device in the sense of the present invention is a device which comprises at least one layer which comprises at least one organic compound. The component may also comprise inorganic materials or also layers which are built up entirely from inorganic materials.

The electronic device is preferably selected from the group consisting of organic electroluminescent devices (OLEDs), 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), dye-sensitised organic solar cells (DSSCs), 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 al., Nature Photonics 2008, 1-4), but preferably organic electroluminescent devices (OLEDs), particularly preferably phosphorescent OLEDs.

The organic electroluminescent device comprises cathode, 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. Interlayers, which have, for example, an exciton-blocking function, may likewise 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 it may comprise a plurality of emitting layers. If a plurality of emission layers are present, these preferably 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). The organic electroluminescent device according to the invention may also be a tandem OLED, in particular also for white-emitting OLEDs.

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), (2) or (3) or the preferred embodiments indicated above as matrix material for fluorescent or phosphorescent emitters and/or as fluorescent emitters, in particular as blue-fluorescent emitters, and/or in an electron-blocking or exciton-blocking layer and/or in a hole-transport layer and/or in a hole-blocking layer and/or in an electron-transport layer, depending on the precise substitution.

In a further embodiment of the invention, the organic electroluminescent device comprises the compound according to the invention in an optical coupling-out layer. An optical coupling-out layer here is taken to mean a layer which is not located between the anode and the cathode, but instead which is applied to an electrode outside the actual device, for example between an electrode and a substrate, in order to improve the optical coupling-out.

In a preferred embodiment of the invention, the compound according to the invention 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 it may comprise 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 according to the invention 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 relatively high spin multiplicity, i.e. a spin state>1, in particular from an excited triplet state. In the sense of this application, all luminescent complexes containing transition metals or lanthanides, in particular all iridium, platinum and copper complexes, are to be regarded as phosphorescent compounds.

The mixture of the compound according to the invention 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 according to the invention, 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.

A further preferred embodiment of the present invention is the use of the compound according to the invention 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 according to the invention 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, WO 2008/086851 or the carbazole derivatives disclosed in the unpublished application EP 11007693.2, indolocarbazole derivatives, for example in accordance with WO 2007/063754 or WO 2008/056746, indenocarbazole derivatives, for example in accordance with WO 2010/136109 or 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 2005/111172, azaboroles or boronic esters, for example in accordance with WO 2006/117052, triazine derivatives, for example in accordance with WO 2007/063754, WO 2008/056746, WO 2010/015306, WO 2011/057706, WO 2011/060859 or WO 2011/060877, 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 WO 2011/042107, WO 2011/060867, WO 2011/088877 and the unpublished application EP 11003232.3, or triphenylene derivatives, for example in accordance with WO 2012/048781. A further phosphorescent emitter which emits at shorter wavelength than the actual emitter may likewise be present in the mixture as co-host.

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 phosphorescence 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.

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 2005/033244, WO 2005/019373, US 2005/0258742, WO 2010/086089, WO 2011/157339 or WO 2012/007086. Also suitable are, for example, the metal complexes disclosed in the unpublished applications EP 11004545.7, EP 11005252.9 and EP 11006562.0. In general, all phosphorescent complexes as are 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 suitable, and the person skilled in the art will be able to use further phosphorescent complexes without inventive step.

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 the same as 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.

Preference is given to the use of the compound of the formula (1), (2) or (3) in a hole-transport or hole-injection or electron-blocking or exciton-blocking layer.

In a preferred embodiment of the invention, the compounds of the formula (1), (2) or (3) are employed as hole-transport material. The compounds are then preferably employed in a hole-transport layer and/or in a hole-injection layer. A hole-injection layer in the sense of this invention is a layer which is directly adjacent to the anode. A hole-transport layer in the sense of this invention is a layer which is located between the hole-injection layer and the emission layer. The hole-transport layer may be directly adjacent to the emission layer.

If the compounds of the formula (1), (2) or (3) are used as hole-transport material or as hole-injection material, it may be preferred for them to be doped with electron-acceptor compounds, for example with F 4 -TCNQ or with compounds as described in EP 1476881 or EP 1596445.

Suitable dopants are in principle all compounds which are electron-acceptor compounds and are able to increase the conductivity of the organic layer by oxidation of the host. The person skilled in the art will be able to identify further suitable compounds without major effort on the basis of his general expert knowledge and employ them in combination with the compounds according to the invention. Particularly suitable dopants are the compounds disclosed in WO 2011/073149, EP 1968131, EP 2276085, EP 2213662, EP 1722602, EP 2045848, DE 102007031220, U.S. Pat. Nos. 8,044,390, 8,057,712, WO 2009/003455, WO 2010/094378, WO 2011/120709, US 2010/0096600 and WO 2012/095143.

In a further preferred embodiment of the invention, a compound of the formula (1), (2) or (3) is used as hole-transport material in combination with a hexaazatriphenylene derivative, as described in US 2007/0092755. The hexaazatriphenylene derivative here is particularly preferably employed in a separate layer.

If the compound of the formula (1), (2) or (3) is employed as hole-transport material in a hole-transport layer, the compound can be employed as pure material, i.e. in a proportion of 100%, in the hole-transport layer, or it can be employed in combination with one or more further compounds in the hole-transport layer.

In still a further preferred embodiment of the invention, the compound according to the invention is employed as electron-transport material in an electron-transport or electron-injection layer. The emitting layer here may be fluorescent or phosphorescent. If the compound is employed as electron-transport material, it may be preferred for it to be doped, for example with alkali-metal complexes, such as, for example, LiQ (lithium hydroxyquinolinate).

In still a further preferred embodiment of the invention, the compound according to the invention is employed in a hole-blocking layer. A hole-blocking layer is taken to mean a layer which is directly adjacent to an emitting layer on the cathode side.

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

Preference is furthermore given to an organic electroluminescent device, characterised in that one or more layers are coated by means of a sublimation process, in which the materials are applied by vapour deposition 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, for example less than 10 −7 mbar.

Preference is likewise given to an organic electroluminescent device, characterised in that one or more layers are coated 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 are 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, screen printing, flexographic printing, offset printing, LITI (light induced thermal imaging, thermal transfer printing), inkjet 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.

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 and the organic electroluminescent devices according to the invention are distinguished by the following surprising advantages over the prior art:

1. The compounds according to the invention, employed as matrix material for fluorescent or phosphorescent emitters, result in very high efficiencies and in long lifetimes. This applies, in particular, if the compounds are employed as matrix material for a phosphorescent emitter. 2. The compounds according to the invention are suitable not only as matrix for red-phosphorescent compounds, but also for green- and possibly also for blue-phosphorescent compounds. 3. The compounds according to the invention are very highly suitable for use in a hole-transport layer or electron-blocking layer, where they result in very good efficiencies and lifetimes of the electronic devices. 4. The compounds according to the invention can be prepared in very high yield and very high purity, which means that complex purification, which is always also associated with losses of material, can be omitted or at least is only necessary to a considerably reduced extent. 5. The compounds according to the invention have high thermal stability, which offers advantages not only in the production of the OLEDs by vacuum evaporation, but also in the purification by sublimation methods.

These advantages mentioned above are not accompanied by an impairment in the other electronic properties.

The invention is explained in greater detail by the following examples without wishing to restrict it thereby. The person skilled in the art will be able to use the descriptions to carry out the invention throughout the range disclosed and prepare further compounds according to the invention without inventive step and use them in electronic devices or apply the process according to the invention.

The following syntheses are carried out, unless indicated otherwise, under a protective-gas atmosphere in dried solvents. The solvents and reagents can be purchased from ALDRICH or ABCR. The numbers in square brackets indicated in the case of the starting materials which are not commercially available are the corresponding CAS numbers.

HIL2

HIL3

ETM1

Alq3

LiQ

SEB1

H1

H2

H3

H4

H5

H6

H7

Irpy

Irppy

Irbic

IrR

IrL