WO2026068426A1 - Materials for organic light emitting diodes - Google Patents

Abstract

The present invention concerns a material for use in an organic light emitting diode (OLED), which is compound according to formula (1), its use in electronic devices, a method for its preparation, and an electronic device, in particular an OLED, comprising the material (compound) according to the formula (1).

Description

Foreignfiling Text P24-169

- 1 -

Materials for organic light emitting diodes

The present invention concerns a material for use in an organic light emitting diode

5 (OLED), a method for its preparation, and an electronic device, in particular an OLED, comprising this material (compound).

Electronic devices in the context of this application are understood to mean what are called organic electronic devices, which comprise organic semiconductor materials as functional materials. More particularly, these are understood to mean OLEDs (organic electroluminescent devices, organic light emitting diodes). The term OLEDs is understood to mean electronic devices which have one or more layers comprising organic compounds and emit light on application of electrical voltage. The construction and general principle of function of OLEDs are known to those skilled in the art. In electronic devices, especially

15 OLEDs, there is great interest in an improvement in the performance data.

A great influence on the performance data of electronic devices is possessed by emission layers and layers having a hole-transporting function. Novel compounds are also being sought for use in these layers, especially hole-transporting compounds and compounds

20 that can serve as hole-transporting matrix material, especially for phosphorescent emitters, in an emitting layer. For this purpose, especially compounds that have a high glass transition temperature and high decomposition temperature, high stability, and high conductivity for holes are being sought for. A high stability of the compound is a prerequisite for achieving a long lifetime of the electronic device. Furthermore, there is a

25 need to find compounds that lead to an improvement of the performance data of the devices using them, and more particularly that lead to a high efficiency, a long lifetime and a low operating voltage, a low lateral leakage current, e.g. leakage current to neighboring pixels that are switched off, as well as a low capacitance/voltage signal, as described for example in more detail in WO 2024/133366. In particular the latter is of great importance for the general charging behaviour of an OLED.

In the prior art, triarylamine compounds, such as for example fluoreneamines, are known as hole transport materials and hole-transporting matrix materials for electronic devices. Examples are 9,9-diarylfluorenes which are substituted with diarylamino groups, such as

35 disclosed in WO 2009/124627, WO 2019/151682, ON 111440156, WO 2024/021264, US 2016/0359113 and WO 2021/170886. Still, there remains room for improvement in respect of the above-mentioned properties. Foreignfiling Text P24-169

It has now been found that aromatic amines of the formula (1) below are of excellent suitability for use in electronic devices. They are especially suitable for use in OLEDs, and even more particularly therein for use as hole transport materials and for use as hole¬

5 transporting matrix materials, especially for phosphorescent emitters. The compounds lead to high lifetime, high efficiency and low operating voltage of the devices, as well as a low lateral current. Further preferably, these compounds have a high glass transition temperature, high thermal stability, i.e. high decomposition temperature, low sublimation temperature, good solubility, good synthetic accessibility and high conductivity for holes.

The present application is thus directed at a compound according to the following formula

Formula (1)

20 where the compound of formula (1) can be partially or fully deuterated and the following applies to the variables and indices present in the formula:

Ar¹, Ar², Ar³, Ar⁴ are each independently an aromatic ring system with 6 to 30 aromatic

25 ring atoms or a heteroaromatic ring system with 5 to 30 aromatic ring atoms, each of which can be can be substituted by one or more substituents R; and where Ar¹, Ar², Ar³, Ar⁴ can be partially or fully deuterated;

R stands on each occurrence, identically or differently, for H, D, F, CN, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 20 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 C atoms, each of which may be substituted by one or more radicals R², where in the alkyl, alkoxy or thioalkyl groups mentioned above one or more H atoms may be replaced by D, F or CN, an aromatic ring system having 6 to 30 aromatic ring atoms or heteroaromatic ring system having 5 to 30 aromatic ring atoms,

35 which may in each case be substituted by one or more radicals R²; where two or more adjacent radicals R may be connected to each other to form a ring; and where R can be partially or fully deuterated; Foreignfiling Text P24-169

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R¹ stands on each occurrence, identically or differently, for a straight-chain alkyl group having 1 to 20 C atoms, a branched alkyl group having 3 to 20 C or a cyclic alkyl group

5 having 3 to 20 C atoms; each of which may be substituted by one or more radicals R², where in the alkyl groups mentioned above one or more H atoms may be replaced by D, F or CN; or two adjactent radicals R¹ form a fused aliphatic ring on Ar²; and where R¹ or the fused aliphatic ring formed by two adjacent R¹ can be partially or fully deuterated;

R² stands on each occurrence, identically or differently, for H, D, F, CN, a straight-chain alkyl 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 R², where in the alkyl, alkoxy or thioalkyl groups mentioned above one or more H atoms may be replaced by D; and where R² can be partially or fully deuterated.

15 n is, identically or differently at each instance, 0, 1 , 2, 3 or 4; m is 0, 1 , 2 or 3;

20 p is 1 , 2, 3 or 4.

The following definitions apply to the chemical groups used as general definitions. They apply insofar as no more specific definitions are given.

25 An aryl group here is taken to mean either a single aromatic ring, for example benzene, or a condensed aromatic polycycle, for example naphthalene, phenanthrene, or anthracene. A condensed aromatic polycycle in the sense of the present application consists of two or more single aromatic rings which are condensed with one another. An aryl group in the sense of this invention contains 6 to 40, preferably 6 to 30, aromatic ring atoms. An aryl group does not contain any heteroatoms as aromatic ring atoms, but only carbon atoms.

A heteroaryl group here is taken to mean either a single heteroaromatic ring, such as pyridine, pyrimidine or thiophene, or a condensed heteroaromatic polycycle, such as quinoline or carbazole. A condensed heteroaromatic polycycle in the sense of the present

35 application consists of two or more single aromatic or heteroaromatic rings, which are condensed with one another, where at least one of the two or more single aromatic or heteroaromatic rings is a heteroaromatic ring. A heteroaryl group in the sense of this Foreignfiling Text P24-169

- 4 - invention contains 5 to 40, preferably 5 to 30, aromatic ring atoms, at least one of which is a heteroatom. The heteroatoms are preferably selected from N, O and S.

5 An aryl or heteroaryl group, which may in each case be substituted by the above- mentioned radicals, is taken to mean, in particular, a group derived from benzene, naphthalene, anthracene, phenanthrene, pyrene, dihydropyrene, chrysene, perylene, fluoranthene, benzanthracene, benzophenanthrene, tetracene, pentacene, benzopyrene, 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, benzimidazolo[1 ,2-a]benzimidazole, naphthimidazole, phenanthrimidazole, pyridimi- dazole, pyrazinimidazole, quinoxalinimidazole, oxazole, benzoxazole, naphthoxazole,

15 anthroxazole, phenanthroxazole, isoxazole, 1 ,2-thiazole, 1 ,3-thiazole, benzothiazole, pyridazine, benzopyridazine, pyrimidine, benzopyrimidine, quinoxaline, pyrazine, phenazine, 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-

20 triazine, 1 ,2,4-triazine, 1 ,2,3-triazine, tetrazole, 1 ,2,4,5-tetrazine, 1 ,2,3,4-tetrazine, 1 , 2,3,5- tetrazine, purine, pteridine, indolizine and benzothiadiazole.

An aromatic ring system in the sense of this invention is a system which does not necessarily contain only aryl groups, but which may additionally contain one or more non¬

25 aromatic rings, which are condensed with at least one aryl group. Such non-aromatic rings contain exclusively carbon atoms as ring atoms. Examples of groups embraced by such definition are tetrahydronaphthalene, fluorene, and spirobifluorene. Furthermore, the term aromatic ring system is understood to embrace systems consisting of two or more aromatic ring systems which are connected to each other via single bonds, such as biphenyl, terphenyl, 7-phenyl-2-fluorenyl and quaterphenyl. An aromatic ring system in the sense of this invention contains 6 to 40 C atoms and no heteroatoms as ring atoms of the ring system. An aromatic ring system in the sense of this application does not comprise any heteroaryl groups, as defined above.

35 A heteroaromatic ring system is defined in analogy to the aromatic ring system above, but with the difference that it must contain at least one heteroatom as one of the ring atoms. As it is the case for the aromatic ring system, it does not necessarily contain only aryl and heteroaryl groups, but it may additionally contain one or more non-aromatic rings, which Foreignfiling Text P24-169

- 5 - are condensed with at least one aryl or heteroaryl group. The non-aromatic rings may contain only carbon atoms as ring atoms, or they may contain additionally one or more heteroatoms, where the heteroatoms are preferably selected from N, O and S. An

5 example for such a heteroaromatic ring system is benzpyranyl. Furthermore, the term heteroaromatic ring system is understood to embrace systems consisting of two or more aromatic or heteroaromatic ring systems, which are connected to each other via single bonds, such as 4,6-diphenyl-2-triazinyl. A heteroaromatic ring system in the sense of this invention contains 5 to 40 ring atoms, which are selected from carbon and heteroatoms, where at least one of the ring atoms is a heteroatom. The heteroatoms are preferably selected from N, O or S.

The terms “heteroaromatic ring system” and “aromatic ring system” according to the definition of the present application differ from each other by the fact that the aromatic ring

15 system cannot comprise any heteroatom as aromatic ring atom, whereas the heteroaromatic ring system must comprise at least one heteroaryl group.

According to the above, any aryl group, as defined above, is embraced by the term “aromatic ring system”, as defined above, and any heteroaryl group, as defined above, is

20 embraced by the term “heteroaromatic ring system”, as defined above.

An aromatic ring system having 6 to 30 aromatic ring atoms or a heteroaromatic ring system having 5 to 30 aromatic ring atoms is in particular a group which is derived from the above-mentioned aryl or heteroaryl groups, or from biphenyl, terphenyl, quaterphenyl,

25 fluorene, spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, indenofluorene, truxene, isotruxene, spirotruxene, spiroisotruxene, and indenocarbazole, or from any combinations of these groups.

For the purposes of the present invention, the expression “alkyl group”, if not specified further, is taken to include linear, as well as branched and/or cyclic alkyl groups. A cyclic alkyl group in the sense of the present invention embraces monocyclic, bicyclic and polycyclic groups. For the purposes of the present invention, a straight-chain alkyl group having 1 to 20 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms is preferably taken to mean the radicals methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl,

35 s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl, cyclopentyl, neopentyl, n-hexyl, cyclohexyl, neohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl or 2-ethylhexyl. Foreignfiling Text P24-169

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The phrase “two or more radicals may be connected to each other to form a ring” shall be understood to include the case that the two radicals are connected by a chemical bond. Additionally, the phrase shall be understood to include the case that one of the two

5 radicals is H, this radical H is removed, and the other of the two radicals forms a ring by being connected to the position, to which this radical H was initially bonded.

Preferred compounds are the compounds of formula (2),

Formula (2)

20 where the the compound of formula (2) can be partially or fully deuterated and the symbols and indices have the meanings as described above.

Preferably, Ar² is an aromatic ring system with 6 to 24 aromatic ring atoms, preferably with 6 to 18 aromatic ring atoms, particularly preferably with 6 to 12 aromatic ring atoms, each of which can be partially or fully deuterated and/or can be substituted by one or more

25 substituents R. Preferred groups Ar² are selected from phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene and naphthyl, each of which can be partially or fully deuterated and/or substituted with one or more substituents R.

More preferably, Ar² is a phenyl group, a biphenyl group or a terphenyl group, each of which can be partially or fully deuterated.

Very preferred compounds are the compounds of formulae (3) and (4), Foreignfiling Text P24-169

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Formula (3) Formula (4)

15 where the compounds of formula (3) and (4) can be partially or fully deuterated, the index q is 0, 1 , 2, 3 or 4 and the other symbols and indices have the meanings as described above.

Even more preferred compounds are the compounds of formulae (3-1) to (3-4), (4-1) to (4-

20 8),

Formula (3-1) Formula (3-2)

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Formula (4-3) Formula (4-4) Foreignfiling Text P24-169

15 Formula (4-5) Formula (4-6)

Formula (4-7) Formula (4-8) where the compounds can be partially or fully deuterated, where Ring R1 corresponds to a fused aliphatic ring formed by two adjactent radicals R¹ and the other symbols and indices have the meanings as described above.

35 Preferably, Ar¹ and Ar⁴ stand, identically or differently, for an aromatic ring system with 6 to 18 aromatic ring atoms, which can be partially or fully deuterated and can be substituted by one or more substituents R, or a heteroaromatic ring system with 5 to 18 aromatic ring atoms comprising a dibenzofuran, dibenzothiophene or carbazole group, Foreignfiling Text P24-169 each of which can be partially or fully deuterated and can be substituted by one or more substituents R.

5 More preferably, Ar¹ and Ar⁴ stand, identically or differently, for an aromatic ring system with 6 to 18, preferably 6 to 12 aromatic ring atoms, which can be partially or fully deuterated and can be substituted by one or more substituents R, or a heteroaromatic ring system selected from dibenzofuran, dibenzothiophene or carbazole, each of which can be partially or fully deuterated and can be substituted by one or more substituents R.

Preferred groups Ar¹ and Ar⁴ are selected, identically or differently, from phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene, naphthyl, dibenzofuran, dibenzothiophene and carbazole, each of which can be partially or fully deuterated and/or substituted with one or more groups R.

15

Examples of preferred groups Ar¹ and Ar⁴ are the structures Ar-1 to Ar-83 below, each of which can be partially or fully deuterated and/or substituted with one or more substituents R,

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25 where the dashed line indicates the bond to the nitrogen, and where:

R° stands on each occurrence, identically or differently, for H, D, a straight-chain alkyl group having 1 to 10, preferably 1 to 6 C atoms or a branched or cyclic alkyl group having 3 to 10, preferably 3 to 6 C atoms, each of which may be substituted by one or more radicals R², where in the alkyl groups mentioned above one or more H atoms may be replaced by D or F, an aromatic ring system having 6 to 12 aromatic ring atoms or heteroaromatic ring system having 6 to 12 aromatic ring atoms, which may in each case

35 be substituted by one or more radicals R²; where two or more adjacent radicals R° may be connected to each other to form a ring; and where R° can be partially or fully deuterated. Foreignfiling Text P24-169

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In structures Ar-48 to Ar-51 and Ar-64 to Ar-67, R° preferably stands on each occurrence, identically or differently, for a straight-chain alkyl group having 1 to 6 C atoms or branched or a cyclic alkyl group having 3 to 6 C atoms, each of which may be substituted by one or

5 more radicals R², where in the alkyl groups mentioned above one or more H atoms may be replaced by D or F, an aromatic ring system having 6 to 12 aromatic ring atoms, which may in each case be substituted by one or more radicals R²; and where R° can be partially or fully deuterated. Examples of very preferred groups R° in structures Ar-48 to Ar-51 and Ar-64 to Ar-67 are methyl and phenyl, which can be partially or fully deuterated

In structures Ar-76 to Ar-83, R° preferably stands on each occurrence, identically or differently, for an aromatic ring system having 6 to 12 aromatic ring atoms, which may in each case be substituted by one or more radicals R²; and where R° can be partially or fully deuterated. Examples of very preferred groups R° in structures Ar-76 to Ar-83 are phenyl,

15 biphenyl and terphenyl, which can be partially or fully deuterated

Examples of very preferred groups Ar¹ and Ar⁴ are the structures Ar-1-1 to Ar-63-1 below, each of which can be partially or fully deuterated.

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20 where the dashed line indicates the bond to the nitrogen.

25

Particularly preferred groups Ar¹ and Ar⁴ are selected, identically or differently, from the structures Ar-1 to Ar-7, Ar-15, Ar-17, Ar-48 to Ar-51 and Ar-56 to Ar-63. Very particularly preferred groups Ar¹ and Ar⁴ are selected, identically or differently, from the structures Ar- 2 to Ar-4, Ar-48 to Ar-51 and Ar-56 to Ar-59.

Preferably, Ar³ is an aromatic ring system with 6 to 24 aromatic ring atoms, preferably with 6 to 18 aromatic ring atoms, particularly preferably with 6 to 12 aromatic ring atoms, each of which can be partially or fully deuterated and/or substituted by one or more substituents R. Preferred groups Ar³ are selected from phenyl, biphenyl, terphenyl, quaterphenyl,

35 fluorene, spirobifluorene and naphthyl, each of which can be partially or fully deuterated and/or substituted with one or more substituents R. More preferred groups Ar³ are Foreignfiling Text P24-169

- 18 - selected from phenyl, biphenyl and fluorenyl, each of which can be partially or fully deuterated and/or substituted with one or more substituents R.

5 Preferred groups Ar³ are selected from the structures Ar-1 to Ar-55 as depicted above, each of which can be partially or fully deuterated and/or substituted with one or more substituents R, and particularly preferred groups Ar³ are selected from the structures Ar-1- 1 to Ar-63-1 as depicted above, each of which can be partially or fully deuterated. Particularly preferably, Ar³ is a phenyl group, a biphenyl group or a fluorenyl group, each of which can be partially or fully deuterated, i.e. a group of one of the formulae Ar-1-1 , Ar-2-1 , Ar-3-1 , Ar-4-1 , Ar-48-1 , Ar-48-2, Ar-49-1 , Ar-49-2, Ar-50-1 , Ar-50-2, Ar-51-1 and Ar-51-2 as depicted above.

In accordance with a preferred embodiment, Ar¹ and Ar⁴ stand, identically or differently,

15 for phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene, naphthyl, dibenzofuran, dibenzothiophene and carbazole, each of which can be partially or fully deuterated and/or substituted with one or more groups R, and Ar³ stands for phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene and naphthyl, each of which can be partially or fully deuterated and can substituted by one or more substituents R.

20

Particularly preferred compounds are selected from the compounds of formulae (3-1 a) to (4-8a),

Formula (3-1 a) Formula (3-2a)

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Formula (4-7a) Formula (4-8a) where the compounds (3-1 a) to (4-8a) can be partially or fully deuterated, where Ring R1 corresponds to a fused aliphatic ring formed by two adjactent radicals R¹, and the other symbols and indices have the meanings as described above.

In accordance with a preferred embodiment, R¹ is, identically or differently at each instance, selected from straight-chain alkyl groups having 1 , 2, 3, 4 or 5 C atoms, Foreignfiling Text P24-169

- 21 - branched alkyl groups having 3, 4 or 5 C atoms, and cyclic alkyl groups having 5 or 6 C atoms, each of which can be partially or fully deuterated and can be further substituted by one or more radicals R²; or two adjacent radicals R¹ form a fused aliphatic ring, Ring R1 ,

5 where Ring R1 is selected from the rings of formulae (Ring-1) to (Ring-7) below:

(Ring-5) (Ring-6) (Ring-7)

20 where

G is the same or different at each instance and is C(R²)2, (R²)2C-C(R²)2, (R²)C=C(R²), O or S, where R² has the same meaning in claim 1 ; and where the dotted bonds represent the sites of attachment to the atoms of the groups to which the two radicals R¹ bind, and

25 where the alkyl groups mentioned above and Ring R1 can be partially or fully deuterated.

More preferably, R¹ is, identically or differently at each instance, selected from methyl, ethyl, propyl, isopropyl, butyl, s-butyl, isobutyl and t-butyl groups, which can be partially of fully deuterated.

Preferably, the group R stands on each occurrence, identically or differently, for H, D, F, a straight-chain alkyl group having 1 to 10 C atoms, particularly preferably 1 , 2, 3, 4 or 5 C atoms, a branched or cyclic alkyl group having 3 to 10 C atoms, particularly preferably a branched alkyl group having 3, 4 or 5 C atoms or a cyclic alkyl group having 5 or 6 C

35 atoms, each of which may be substituted by one or more radicals R²; or an aromatic ring system having 6 to 24 aromatic ring atoms, particularly preferably 6 to 18 aromatic ring atoms and very particularly preferred 6 to 12 aromatic ring atoms, where the aromatic ring system can be substituted with one or more radicals R²; or an heteroaromatic ring system Foreignfiling Text P24-169

- 22 - having 6 to 24 aromatic ring atoms, particularly preferably 6 to 18 aromatic ring atoms and very particularly preferred 6 to 12 aromatic ring atoms, where the heteroaromatic ring system can be substituted with one or more radicals R²; where two adjacent radicals R

5 may be connected to each other to form a ring, and where R can be partially or fully deuterated. Particularly preferred groups R, if present, are identically or differently at each instance, methyl or phenyl, each of which can be partially or fully deuterated.

Preferably, R², if present, is identically or differently at each instance an alkyl group having 1 to 10 C atoms, particularly preferably having 1 , 2, 3, 4 or 5 C atoms and most preferred methyl, each of which can be partially or fully deuterated.

As described above, the inventive compounds can be partially or fully deuterated. If the compound is deuterated, a degree of deuteration of at least 20 % is preferred. The term

15 “deuterated” has the meaning that in such a compound the corresponding portion of the H atoms of the undeuterated compound are exchanged for D (deuterium). The undeuterated compound is the corresponding compound, which contains hydrogen in the natural isotope distribution. The degree of deuteration relates to mol% and designates the average degree of deuteration of the compound, i.e. the average fraction of the H atoms

20 in the compound which are replaced by D atoms. In a fully deuterated compound, all H atoms are replaced by D, and the degree of deuteration is 100 %. A degree of deuteration of at least 20 % has the meaning that in average 20 to 100 % of the H atoms in the compound are replaced by D atoms. In a preferred embodiment of the invention, the degree of deuteration is 30 to 95 %, particularly preferred 40 to 90 % and very particularly

25 preferred 50 to 80 %. In general, a high degree of deuteration is desirable. This, however, can be achieved only with a very high synthetic effort, if it can be achieved at all. As the indication of the degree of deuteration relates to the average of a mixture of differently deuterated compounds, such a mixture comprises compounds of the same backbone, wherein the single compounds differ in the position and degree of deuteration.

Preferred specific compounds according to formula (1) are the following ones:

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15 The compounds according to formula (1) may be prepared by synthesis methods such as Buchwald coupling and Suzuki coupling. The skilled person is aware of several possible synthetic routes, based on his general knowledge of organic synthetic chemistry. A suitable synthetic route to prepare compounds according to formula (1) is described in the following: For preparation of the compound according to formula (1), 9-aryl-9-phenyl-

20 fluorene derivative which is substituted with two different reactive leaving groups, preferably in the 3- and 5-position of the phenyl group, is first reacted with the group Ar², which bears a boronic acid or boronic ester leaving group and at least one group R¹, in a Suzuki coupling reaction. The reaction takes place on the position bearing the more reactive of the two leaving groups, which are preferably present in 3, 5-position of the

25 phenyl group. The resulting intermediate is then reacted on the position of the phenyl group bearing the less reactive leaving group with a secondary amine bearing a group Ar¹ and a group Ar⁴ in a Hartwig-Buchwald coupling reaction to result in a compound of formula (1). Further reactions, such as deuteration of the compound, may follow. Suitable reactive leaving groups of the phenyl group are chloride, bromide, iodide, tosylate and triflate. The reactants described are in many cases commercially available. Specific starting materials and reactants needed to obtain specific compounds according to formula (1) that are not available commercially, can be prepared using methods known to the skilled person. The synthesis is illustrated in the following Scheme 1.

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Scheme 1 where L¹ and L² represent leaving groups and are preferably different from each other, and the other symbols and indices have the same meanings as defined above. In a

20 preferable embodiment, L¹ and L² are two different groups selected from chloride, bromide, iodide, tosylate and triflate, where chloride and bromide are preferred.

Object of the present patent application is therefore a process for preparation of a compound according to formula (1) and the preferred embodiments, characterised by the

25 following reaction steps:

(a) reacting a 9-aryl-9-phenyl-fluorene derivative, which is preferably substituted in the 3- and 5-position of the phenyl group with two different reactive leaving groups with a compound Ar² which bears a boronic acid or boronic ester as a leaving group and a group R¹ in a Suzuki coupling reaction; and

(b) reaction the intermediate obtained in step (a) with a secondary amine bearing a group Ar¹ and a group Ar⁴ in a Hartwig-Buchwald coupling reaction.

35 where Ar1 , Ar², Ar³, Ar⁴, R¹, R and the indices m, n and p have the same meaning as above. Foreignfiling Text P24-169

- 40 -

Deuterated compounds can be obtained by different processes, for example by reacting building blocks together, where at least one of the builing block is partly or completely deuterated (like in WO 2011/050888) or by deuterating the compound once it has been

5 synthesized (like in WO 2010/099534). For example, undeuterated compounds can be treated with deuterated acids such as D2SO4 or D3PO4 for several hours to obtain deuterated compounds. It is also possible to react undeuterated compound in a deuterated solvent in the presence of a Lewis acid such as aluminum trichloride to obtain deuterated compounds. There are also some deuteration methods using high temperatures and electrical voltage or radiation. Other deuteration methods use D2 gas, D2O, or a deuterated solvent such as CeDe as a deuterium source to perform a H-D exchange by metal catalysis like in WO 2016/073425 or KR101978651. Other methods for deuteration of aromatic compounds use an acid catalyst and a deuterated aromatic solvent as deuterium source like in WO 2011/053334.

15

The above-described compounds, especially compounds substituted by reactive leaving groups, such as bromine, iodine, chlorine, boronic acid or boronic ester, may find use as monomers for production of corresponding oligomers, dendrimers or polymers. Suitable reactive leaving groups are, for example, bromine, iodine, chlorine, boronic acids, boronic

20 esters, amines, alkenyl or alkynyl groups having a terminal C-C double bond or C-C triple bond, oxiranes, oxetanes, groups which enter into a cycloaddition, for example a 1,3- dipolar cycloaddition, for example dienes or azides, carboxylic acid derivatives, alcohols and silanes.

25 The invention therefore further provides oligomers, polymers or dendrimers containing one or more compounds of formula (1), wherein the bond(s) to the polymer, oligomer or dendrimer may be localised at any desired positions substituted of formula (1). According to the linkage of the compound of formula (1), the compound is part of a side chain of the oligomer or polymer or part of the main chain.

For the processing of the compounds of the invention from a liquid phase, for example by spin-coating or by printing methods, formulations of the compounds of the invention are required. These formulations may, for example, be solutions, dispersions or emulsions. For this purpose, it may be preferable to use mixtures of two or more solvents. Suitable

35 solvents are generally known to the skilled person. The invention therefore further provides a formulation, especially a solution, dispersion or emulsion, comprising at least one compound of formula (1) or at least one polymer, oligomer or dendrimer containing at Foreignfiling Text P24-169

- 41 - least one unit of formula (1) and at least one solvent, preferably an organic solvent. The way in which such solutions can be prepared is known to those skilled in the art.

5 The compound of formula (1) is suitable for use in an electronic device, especially an organic electroluminescent device (OLED). Depending on the substitution, the compound of the formula (1) can be used in different functions and layers. Preference is given to use as a hole-transporting material in a hole-transporting layer and/or as matrix material in an emitting layer, more preferably in combination with a phosphorescent emitter.

The invention therefore further provides for the use of a compound of formula (1) in an electronic device. This electronic device is preferably selected from the group consisting of organic integrated circuits (OlCs), organic field-effect transistors (OFETs), organic thin- film transistors (OTFTs), organic light-emitting transistors (OLETs), organic solar cells

15 (OSCs), organic optical detectors, organic photoreceptors, organic field-quench devices (OFQDs), organic light-emitting electrochemical cells (OLECs), organic laser diodes (O- lasers) and more preferably organic electroluminescent devices (OLEDs).

The invention further provides an electronic device comprising at least one compound of

20 formula (1). This electronic device is preferably selected from the above-mentioned devices.

Particular preference is given to an organic electroluminescent device comprising anode, cathode and at least one emitting layer, characterized in that at least one organic layer

25 comprising at least one compound of formula (1) is present in the device. Preference is given to an organic electroluminescent device comprising anode, cathode and at least one emitting layer, characterized in that at least one organic layer in the device, selected from hole-transporting and emitting layers, preferably selected from hole-transporting layers, comprises at least one compound of formula (1).

A hole-transporting layer is understood here to mean all layers disposed between anode and emitting layer, preferably hole injection layer, hole transport layer and electron blocking layer. A hole injection layer is understood here to mean a layer that directly adjoins the anode. A hole transport layer is understood here to mean a layer which is

35 between the anode and emitting layer but does not directly adjoin the anode, and preferably does not directly adjoin the emitting layer either. An electron blocking layer is understood here to mean a layer which is between the anode and emitting layer and Foreignfiling Text P24-169

- 42 - directly adjoins the emitting layer. An electron blocking layer preferably has a high-energy LIIMO and hence prevents electrons from exiting from the emitting layer.

5 Apart from the cathode, anode and emitting layer, the electronic device may comprise further layers. These are selected, for example, from in each case one or more hole injection layers, hole transport layers, hole blocking layers, electron transport layers, electron injection layers, electron blocking layers, exciton blocking layers, interlayers, charge generation layers and/or organic or inorganic p/n junctions. However, it should be pointed out that not every one of these layers need necessarily be present and the choice of layers always depends on the compounds used and especially also on whether the device is a fluorescent or phosphorescent electroluminescent device.

The sequence of layers in the electronic device is preferably as follows:

15 - anode

- hole injection layer

- hole transport layer

- optionally further hole transport layers

- optionally electron blocking layer

20 - emitting layer

- optionally hole blocking layer

- electron transport layer

- electron injection layer

- cathode.

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

The sequence of layers in the electronic device is very preferably as follows:

- anode

- hole injection layer

- hole transport layer

- optionally further hole transport layers

- electron blocking layer

- emitting layer

35 - optionally hole blocking layer

- electron transport layer

- electron injection layer

- cathode. Foreignfiling Text P24-169

- 43 -

The sequence of layers in the electronic device is particularly preferably as follows:

- anode

5 - hole injection layer

- hole transport layer

- optionally further hole transport layers

- first electron blocking layer

- second electron blocking layer

- emitting layer

- optionally hole blocking layer

- electron transport layer

- electron injection layer

- cathode.

15

Preferably, the electronic device is an organic electroluminescent device.

Therefore, one aspect of the invention is an organic electroluminescent device comprising a hole injection layer and a hole-transporting layer, where the hole-transporting layer comprises at least one compound of formula (1).

20

A preferred aspect of the invention is an organic electroluminescent device comprising in the following sequence: a hole injection layer, a hole-transporting layer and an electronblocking layer, where the electron-blocking layer comprises at least one compound of formula (1).

25

A very preferred aspect of the invention is an organic electroluminescent device comprising in the following sequence: a hole injection layer, a hole-transporting layer, a first electron-blocking layer, a second-electron blocking layer and an emitting layer, where the second-electron blocking layer is adjacent to the emitting layer and the second electron-blocking layer comprises at least one compound of formula (1).

The organic electroluminescent device of the invention may contain two or more emitting layers. More preferably, these emission layers have several emission maxima between 380 nm and 750 nm overall, such that the overall result is white emission; in other words,

35 various emitting compounds which may fluoresce or phosphoresce and which emit blue, green, yellow, orange or red light are used in the emitting layers. Especially preferred are three-layer systems, i.e. systems having three emitting layers, wherein one of the three layers in each case shows blue emission, one of the three layers in each case shows Foreignfiling Text P24-169

- 44 - green emission, and one of the three layers in each case shows orange or red emission. The compounds of the invention here are preferably present in a hole-transporting layer or in the emitting layer. It should be noted that, for the production of white light, rather than a

5 plurality of colour-emitting emitter compounds, an emitter compound used individually which emits over a broad wavelength range may also be suitable.

It is preferable that the compound of the formula (1) is used as hole transport material. The emitting layer here may be a fluorescent emitting layer, or it may be a phosphorescent emitting layer. The emitting layer is preferably a blue-fluorescing layer or a green-phosphorescing layer.

When the device containing the compound of the formula (1) contains a phosphorescent emitting layer, it is preferable that this layer contains two or more, preferably exactly two,

15 different matrix materials (mixed matrix system). Preferred embodiments of mixed matrix systems are described in detail further down.

If the compound of formula (1) is used as hole transport material in a hole transport layer, a hole injection layer or an electron blocking layer, the compound can be used as pure

20 material, i.e. in a proportion of 100%, in the hole transport layer, or it can be used in combination with one or more further compounds.

In a preferred embodiment, a hole-transporting layer comprising the compound of the formula (1) additionally comprises one or more further hole-transporting compounds.

25 These further hole-transporting compounds are preferably selected from triarylamine compounds, more preferably from monotriarylamine compounds. They are most preferably selected from the preferred embodiments of hole transport materials that are specified further down. In the preferred embodiment described, the compound of the formula (1) and the one or more further hole-transporting compounds are preferably each present in a proportion of at least 10%, more preferably each in a proportion of at least 20%.

In a preferred embodiment, a hole-transporting layer comprising the compound of the formula (1) additionally contains one or more p-dopants. p-Dopants used according to the

35 present invention are preferably those organic electron acceptor compounds capable of oxidizing one or more of the other compounds in the mixture. Foreignfiling Text P24-169

- 45 -

Particularly preferred as p-dopants are quinodimethane compounds, azaindenofluorene- diones, azaphenalenes, azatriphenylenes, I2, metal halides, preferably transition metal halides, metal oxides, preferably metal oxides comprising at least one transition metal or a

5 metal from main group 3, and transition metal complexes, preferably complexes of Cu, Co, Ni, Pd and Pt with ligands containing at least one oxygen atom as binding site. Preference is further given to transition metal oxides as dopants, preferably oxides of rhenium, molybdenum and tungsten, more preferably Re2O?, MoOa, WO3 and ReCh. Still further preference is given to complexes of bismuth in the (III) oxidation state, more particularly bismuth(lll) complexes with electron-deficient ligands, more particularly carboxylate ligands.

The p-dopants are preferably in substantially homogeneous distribution in the p-doped layers. This can be achieved, for example, by co-evaporation of the p-dopant and the hole

15 transport material matrix. The p-dopant is preferably present in a proportion of 1 % to 10% in the p-doped layer.

Preferred p-dopants are furthermore the compounds which are explicitly disclosed in the table on p. 86-87 of WO2021/156323A1.

20

In a preferred embodiment, a hole injection layer that conforms to one of the following embodiments is present in the device: a) it contains a triarylamine and a p-dopant; or b) it contains a single electron-deficient material (electron acceptor). In a preferred embodiment of embodiment a), the triarylamine is a monotriarylamine, especially one of

25 the preferred triarylamine derivatives mentioned further down. In a preferred embodiment of embodiment b), the electron-deficient material is a hexaazatriphenylene derivative as described in US 2007/0092755.

The compound of the formula (1) may be present in a hole injection layer, in a hole transport layer and/or in an electron blocking layer of the device. When the compound is present in a hole injection layer or in a hole transport layer, it has preferably been p- doped, meaning that it is in mixed form with a p-dopant, as described above, in the layer.

The compound of the formula (1) is preferably present in an electron blocking layer. In this

35 case, it is preferably not p-doped. Further preferably, in this case, it is preferably in the form of a single compound in the layer without addition of a further compound. Foreignfiling Text P24-169

- 46 -

In an alternative preferred embodiment, the compound of the formula (1) is used in an emitting layer as matrix material in combination with one or more emitting compounds, preferably phosphorescent emitting compounds. The phosphorescent emitting

5 compounds here are preferably selected from red-phosphorescing and greenphosphorescing compounds.

The proportion of the matrix material in the emitting layer in this case is between 50.0% and 99.9% by volume, preferably between 80.0% and 99.5% by volume, and more preferably between 85.0% and 97.0% by volume.

Correspondingly, the proportion of the emitting compound is between 0.1% and 50.0% by volume, preferably between 0.5% and 20.0% by volume, and more preferably between 3.0% and 15.0% by volume.

15

An emitting layer of an organic electroluminescent device may also contain systems comprising a plurality of matrix materials (mixed matrix systems) and/or a plurality of emitting compounds. In this case too, the emitting compounds are generally those compounds having the smaller proportion in the system and the matrix materials are those

20 compounds having the greater proportion in the system. In individual cases, however, the proportion of a single matrix material in the system may be less than the proportion of a single emitting compound.

It is preferable that the compounds of formula (1) are used as a component of mixed

25 matrix systems, preferably for phosphorescent emitters. The mixed matrix systems preferably comprise two or three different matrix materials, more preferably two different matrix materials. Preferably, in this case, one of the two materials is a material having hole-transporting properties and the other material is a material having electrontransporting properties. It is further preferable when one of the materials is selected from compounds having a large energy differential between HOMO and LIIMO (wide-bandgap materials). The compound of the formula (1) in a mixed matrix system is preferably the matrix material having hole-transporting properties. Correspondingly, when the compound of the formula (1) is used as matrix material for a phosphorescent emitter in the emitting layer of an OLED, a second matrix compound having electron-transporting properties is

35 present in the emitting layer. The two different matrix materials may be present here in a ratio of 1:50 to 1:1, preferably 1 :20 to 1:1 , more preferably 1 :10 to 1:1 and most preferably 1:4 to 1:1. Foreignfiling Text P24-169

- 47 -

The desired electron-transporting and hole-transporting properties of the mixed matrix components may, however, also be combined mainly or entirely in a single mixed matrix component, in which case the further mixed matrix component(s) fulfil(s) other functions.

5

Preference is given to using the following material classes in the above-mentioned layers of the device:

Phosphorescent emitters: The term "phosphorescent emitters" typically encompasses compounds where the emission of light is effected through a spin-forbidden transition, for example a transition from an excited triplet state or a state having a higher spin quantum number, for example a quintet state. Suitable phosphorescent emitters are especially compounds which, when suitably excited, emit light, preferably in the visible region, and also contain at least one atom of atomic number greater than 20, preferably greater than

15 38, and less than 84, more preferably greater than 56 and less than 80. Preference is given to using, as phosphorescent emitters, compounds containing copper, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver, gold or europium, especially compounds containing iridium, platinum or copper. In the context of the present invention, all luminescent iridium, platinum or copper complexes are

20 considered to be phosphorescent compounds.

In general, all phosphorescent complexes as used for phosphorescent OLEDs according to the prior art and as known to those skilled in the art in the field of organic electroluminescent devices are suitable for use in the devices of the invention. Further examples

25 of suitable phosphorescent emitters are those shown in the table on p.100-104 of WO2023/025971A2.

Fluorescent emitters: Preferred fluorescent emitting compounds are selected from the class of the arylamines. An arylamine or an aromatic amine in the context of this invention is understood to mean a compound containing three substituted or unsubstituted aromatic or heteroaromatic ring systems bonded directly to the nitrogen. Preferably, at least one of these aromatic or heteroaromatic ring systems is a fused ring system, more preferably having at least 14 aromatic ring atoms. Preferred examples of these are aromatic anthraceneamines, aromatic anthracenediamines, aromatic pyreneamines, aromatic

35 pyrenediamines, aromatic chryseneamines or aromatic chrysenediamines. An aromatic anthraceneamine is understood to mean a compound in which a diarylamino group is bonded directly to an anthracene group, preferably in the 9 position. An aromatic anthracenediamine is understood to mean a compound in which two diarylamino groups Foreignfiling Text P24-169

- 48 - are bonded directly to an anthracene group, preferably in the 9,10 position. Aromatic pyreneamines, pyrenediamines, chryseneamines and chrysenediamines are defined analogously, where the diarylamino groups are bonded to the pyrene preferably in the 1

5 position or 1,6 position. Further preferred emitting compounds are indenofluoreneamines or -diamines, benzoindenofluoreneamines or -diamines, and dibenzoindenofluorene- amines or -diamines, and indenofluorene derivatives having fused aryl groups. Likewise preferred are pyrenearylamines. Likewise preferred are benzoindenofluoreneamines, benzofluoreneamines, extended benzoindenofluorenes, phenoxazines, and fluorene derivatives joined to furan units or to thiophene units.

Matrix materials for fluorescent emitters: Preferred matrix materials for fluorescent emitters are selected from the classes of the oligoarylenes (e.g. 2,2’,7,7’-tetraphenyl- spirobifluorene), especially the oligoarylenes containing fused aromatic groups, the

15 oligoarylenevinylenes, the polypodal metal complexes, the hole-conducting compounds, the electron-conducting compounds, especially ketones, phosphine oxides and sulfoxides; the atropisomers, the boronic acid derivatives or the benzanthracenes. Particularly preferred matrix materials are selected from the classes of the oligoarylenes comprising naphthalene, anthracene, benzanthracene and/or pyrene or atropisomers of these

20 compounds, the oligoarylenevinylenes, the ketones, the phosphine oxides and the sulfoxides. Very particularly preferred matrix materials are selected from the classes of the oligoarylenes comprising anthracene, benzanthracene, benzophenanthrene and/or pyrene or atropisomers of these compounds. An oligoarylene in the context of this invention shall be understood to mean a compound in which at least three aryl or arylene groups are

25 bonded to one another.

Matrix materials for phosphorescent emitters: Preferred matrix materials for phosphorescent emitters are, as well as the compounds of the formula (1), aromatic ketones, aromatic phosphine oxides or aromatic sulfoxides or sulfones, triarylamines, carbazole derivatives, e.g. CBP (N,N-biscarbazolylbiphenyl) or carbazole derivatives, indolocarbazole derivatives, indenocarbazole derivatives, azacarbazole derivatives, bipolar matrix materials, silanes, azaboroles or boronic esters, triazine derivatives, zinc complexes, diazasilole or tetraazasilole derivatives, diazaphosphole derivatives, bridged carbazole derivatives, triphenylene derivatives, or lactams.

35

Electron-transporting materials: Suitable electron-transporting materials are, for example, the compounds disclosed in Y. Shirota et al., Chem. Rev. 2007, 107(4), 953-1010, or other materials used in these layers according to the prior art. Materials used for the Foreignfiling Text P24-169

- 49 - electron transport layer may be any materials that are used as electron transport materials in the electron transport layer according to the prior art. Especially suitable are aluminium complexes, for example Alqa, zirconium complexes, for example Zrq4, lithium complexes,

5 for example Liq, benzimidazole derivatives, triazine derivatives, pyrimidine derivatives, pyridine derivatives, pyrazine derivatives, quinoxaline derivatives, quinoline derivatives, oxadiazole derivatives, aromatic ketones, lactams, boranes, diazaphosphole derivatives and phosphine oxide derivatives. Preferred electron transport and electron injection materials are those shown in the table on p. 73-75 of W02020/109434A1.

Hole-transporting materials: Further compounds which, in addition to the compounds of the formula (1), are preferably used in hole-transporting layers of the OLEDs of the invention are indenofluoreneamine derivatives, amine derivatives, hexaazatriphenylene derivatives, amine derivatives with fused aromatic systems, monobenzoindenofluorene-

15 amines, dibenzoindenofluoreneamines, spirobifluoreneamines, fluoreneamines, spirodibenzopyranamines, dihydroacridine derivatives, spirodibenzofurans and spirodibenzothiophenes, phenanthrenediarylamines, spirotribenzotropolones, spirobifluorenes having meta-phenyldiamine groups, spirobisacridines, xanthenediarylamines, and 9,10-dihydro- anthracene spiro compounds having diarylamino groups. Preferred hole-transporting

20 compounds are those shown the table on p. 76-80 of W02020/109434A1.

Preferred cathodes of the electronic device are metals having a low work function, metal alloys or multilayer structures composed of various metals, for example alkaline earth metals, alkali metals, main group metals or lanthanoids (e.g. Ca, Ba, Mg, Al, In, Mg, Yb,

25 Sm, etc.). Additionally suitable are alloys composed of an alkali metal or alkaline earth metal and silver, for example an alloy composed of magnesium and silver. In the case of multilayer structures, in addition to the metals mentioned, it is also possible to use further metals having a relatively high work function, for example Ag or Al, in which case combinations of the metals such as Ca/Ag, Mg/Ag or Ba/Ag, for example, are generally used. It may also be preferable to introduce a thin interlayer of a material having a high dielectric constant between a metallic cathode and the organic semiconductor. Examples of useful materials for this purpose are alkali metal or alkaline earth metal fluorides, but also the corresponding oxides or carbonates (e.g. LiF, U2O, BaF2, MgO, NaF, CsF, CS2CO3, etc.). It is also possible to use lithium quinolinate (LiQ) for this purpose. The layer

35 thickness of this layer is preferably between 0.5 and 5 nm.

Preferred anodes are materials having a high work function. Preferably, the anode has a work function of greater than 4.5 eV versus vacuum. Firstly, metals having a high redox Foreignfiling Text P24-169

- 50 - potential are suitable for this purpose, for example Ag, Pt or Au. Secondly, metal/metal oxide electrodes (e.g. Al/N i/N iO_x, AI/PtO_x) may also be preferred. For some applications, at least one of the electrodes has to be transparent or partly transparent in order to enable

5 either the irradiation of the organic material (organic solar cell) or the emission of light (OLED, O-LASER). Preferred anode materials here are conductive mixed metal oxides. Particular preference is given to indium tin oxide (ITO) or indium zinc oxide (IZO). Preference is further given to conductive doped organic materials, especially conductive doped polymers. In addition, the anode may also consist of two or more layers, for example of an inner layer of ITO and an outer layer of a metal oxide, preferably tungsten oxide, molybdenum oxide or vanadium oxide.

In a preferred embodiment, the electronic device is characterized in that one or more layers are coated by a sublimation process. In this case, the materials are applied by

15 vapour deposition in vacuum sublimation systems at an initial pressure of less than 10^-5 mbar, preferably less than 10'⁶ mbar. In this case, however, it is also possible that the initial pressure is even lower, for example less than 10'⁷ mbar.

Preference is likewise given to an electronic device, characterized in that one or more

20 layers are coated by the OVPD (organic vapour phase deposition) method or with the aid of a carrier gas sublimation. In this case, the materials are applied at a pressure between 10^-5 mbar and 1 bar. A special case of this method is the OVJP (organic vapour jet printing) method, in which the materials are applied directly by a nozzle and thus structured (for example M. S. Arnold et al., Appl. Phys. Lett. 2008, 92, 053301).

25

Preference is additionally given to an electronic device, characterized in that one or more layers are produced from solution, for example by spin-coating, or by any printing method, for example screen printing, flexographic printing, nozzle printing or offset printing, but more preferably LITI (light-induced thermal imaging, thermal transfer printing) or inkjet printing. For this purpose, soluble compounds of formula (1) are needed. High solubility can be achieved by suitable substitution of the compounds.

It is further preferable that an electronic device of the invention is produced by applying one or more layers from solution and one or more layers by a sublimation method.

35

After application of the layers, according to the use, the device is structured, contact- connected and finally sealed, in order to rule out damaging effects of water and air. Foreignfiling Text P24-169

- 51 -

According to the invention, the electronic devices comprising one or more compounds of formula (1) can be used in displays or as light sources in lighting applications.

5 The compounds of the present invention have the following advantages, which are based on the presence of a group Ar² and simulateously the presence of a 1-dibenzofuran, 4- fluorene, 1-dibenzothiophene or 4-carbazole group on the amine:

(1) The inventive compounds have an improved glass transition temperature.

(2) The inventive compounds have an improved thermal stability which is shown by a higher decomposition temperature.

(3) The inventive compounds when used in a hole-transporting layer of an OLED result in very good device properties with respect to efficiency, lifetime and operating voltage.

(4) Due to the higher LIIMO of the inventive compounds compared to similar compounds

15 of the prior art, the inventive compound have better electron-blocking properties when used in an electron-blocking layer of an OLED.

(5) The inventive compounds when used in a hole-transporting layer of an OLED result in an improved, i.e. a lower lateral current (less crosstalk).

20 The invention is now illustrated in detail by the examples which follow, without any intention of restricting it thereby.

Examples

25 Synthesis of lnt-1

In a 1-L 3-necked round bottom flask magnesium turnings (7.50 g, 309 mmol, 1.15 eq.) are dried under N2. After cooling to RT, anhydrous Et20 (240 mL) and 1,2-dibromoethane (5 drops) are added. The mixture is slightly heated to 35 °C. A solution of 2-

35 Bromobiphenyl (50.9 mL, 295 mmol, 1.1 eq) in anhydrous Et20 (240 mL) is charged in an addition funnel and approx. 3 mL of the solution is added to the reaction at 35 °C. The rest of the 2-bromobiphenyl solution is added dropwise into the reaction over 1 h. Once the Foreignfiling Text P24-169

- 52 - addition is complete, the mixture is stirred at reflux temperature for 30 min. In a second 2L 3-necked round bottom flask is prepared a solution of (3-bromo-5-chlorophenyl) (phenyl)- methanone (79.3 g, 268 mmol) in anhydrous Et20 (240 mL). At 35 °C, the solution of

5 biphenyl magnesium bromide is slowly added to the solution of (3-bromo-5-chlorophenyl)- (phenyl)methanone over 30 min. The reaction mixture is stirred at reflux temperature for 1 h. The reaction mixture is cooled to 0-5°C with an ice bath and the reaction is quenched with sat. NH4CI (400 mL).The layers are separated and the aqueous layer is extracted with EtOAc (2 x 300 mL). The combined organic layers are washed with 5% NaCI (300 mL), dried over MgSCL and evaporated under reduced pressure to provide the crude product, which is further prurified by crystallization out of heptane.

Yield: 91.7 g, (203 mmol, 76% ).

15 Synthesis of lnt-2

TfOH

DCM

20 lnt-2

91.7 g (204 mmol) of lnt-1 are dissolved in DCM (900 mL under N2. The mixture is cooled

25 to 0 °C with an ice/water bath and TfOH (36.2 mL, 408 mmol, 2 eq) is added dropwise over 15 min and stirred at room temperature for 1 h. The solution iss quenched with H2O (450 mL) and 270 mL sat. NaHCCh is added over 10 min and the mixture is stirred for 30 min. The aqueous layer is extracted with DCM (2 x 270 mL). The combined organic layers are washed with sat. NaHCCh (270 mL), 5%. NaCI (270 mL), dried over MgSO4 and evaporated under reduced pressure to provide the crude product, which is further purified by refluxing in heptane and after cooling down to 0°C the product is filtered off and washed with cold heptane to provide lnt-2 as a off-white solid.

Yield: 81.9 g, (190 mmol, 93%).

35 Foreignfiling Text P24-169

- 53 -

Synthesis of lnt-3a

20.0 g (46.3 mmol) lnt-2, 10.85 g (46.3 mmol) SM-1 and 20.65 g (97.3 mmol) potassium phosphate are dissolved in 160 mL toluene/dioxane/water (2:1 :1). 104 mg (0.46 mmol) palladium^ I) acetate and 282.0 mg (0.93 mmol) tri(o-tilyl)phosphine are added and the mixture is refluxed for 3 hours until full conversion. After cooling down to room

15 temperature the reaction mixture is filtered through celite, and the phases are separated. The organic phase is evaporated under reduced pressure to provide the crude product, which is further purified by column chromatography (SiC>2; heptane) to give the product as colorless solid.

20 Yield: 14.0 g (24.99 mmol, 54%).

The following compounds can be synthesized in analogous manner:

25

35 Foreignfiling Text P24-169

- 54 -

5

15

20

Synthesis of compound 1

16.5 g (30.3mmol) lnt-3a, 10.94 g (30.3 mmol) 897671-69-1 and 16.7 g (0.06 mmol) sodium-tert-pentoxide are dissolved in 160 mL toluene. 1.28 g (1.51 mmol) X-Phos Pd G3 are added, and the mixture is refluxed overnight. After cooling down to room temperature

35 200 mL water are added. The layers are separated, and the aqueous layer is extracted with EtOAc (2 x 300 mL). The combined organic layers are washed with 5% NaCI (300 mL), dried over MgSCL and evaporated under reduced pressure to provide the crude product. The product is further purified by filtration over aluminum oxide and crystallization Foreignfiling Text P24-169

- 55 - out of heptane until a HPLC purity of >99.9% and the remaining solvents are removed by sublimation (340 °C at 10'⁶ bar).

5 Yield: 13.60 g (15.68 mmol, 52%).

Following compounds can be synthesized in analogous manner:

15

20

25

35 Foreignfiling Text P24-169

- 56-

5

15

20

25

35 Foreignfiling Text P24-169

- 57 -

Synthesis of compound 2-D

15

17.2 g of compound 2 (22.3 nmmol; 1 ,00 eq) is suspended in 190 mL (80 eq) toluene-d8 and cooled down to 0°C. 20 mL (10.00 eq.) trifluoromethanesulfonic acid are added and the mixture is stirred at room temperature. After 6 hours 40 mL (130 eq) of D2O are added slowly at 0°C. after one hour the mixture is neutralized with and aqueous solution of

20 NaOH (38 mL; 20%) and 150 ml heptane are added to the mixture, and the precipitated solid is filtered off and washed with ethanol. To remove the remaining solvents the compound-1 D and the mixture of H/D-isotopomers and H/D-isotopologues are sublimed (p = 5 x 10'⁷ mbar).

25

Yield (13.2 g, 16.3 mmol, 73 %) purity 99,9%).

Device examples

1) General production process for the OLEDs and characterization of the OLEDs

Glass plaques which have been coated with structured ITO (indium tin oxide) in a thickness of 50 nm are the substrates to which the OLEDs are applied.

35

The OLEDs basically have the following layer structure: substrate / hole injection layer (HIL) / hole transport layer (HTL) / electron blocker layer (EBL) / optionally, instead of a single electron blocking layer, a first electron-blocking layer (EBL1) and a second Foreignfiling Text P24-169

- 58 - electron-blocking layer (EBL2) I emission layer (EML) / electron transport layer, optionally with second layer (ETL) / electron injection layer (EIL) and finally a cathode. The cathode is formed by an aluminium layer of thickness 100 nm. The exact structure of

5 the OLEDs can be found in the tables which follow. The materials used for production of the OLEDs are shown in a table below.

All materials are applied by thermal vapour deposition in a vacuum chamber. In this case, the emission layer consists of at least one matrix material (host material) and an emitting dopant which is added to the matrix material(s) in a particular proportion by volume by coevaporation. Details given in such a form as TMM-1 (32%):TMM-2 (60%):TEG(8%) mean here that the material TMM-1 is present in the layer in a proportion by volume of 32%, TMM-2 is present in the layer in a proportion by volume of 60% and TEG in a proportion of 8%. In an analogous manner, the electron transport layer and the hole injection layer also

15 consist of a mixture of two materials. The structures of the materials that are used in the OLEDs are shown in Table 3.

The OLEDs are characterized in a standard manner. For this purpose, the electroluminescence spectra, the external quantum efficiency (EQE, measured in %) as a

20 function of the luminance, calculated from current-voltage-luminance characteristics assuming Lambertian radiation characteristics, and the lifetime are determined. The parameter EQE @ 10 mA/cm² refers to the external quantum efficiency which is attained at 10 mA/cm². The parameter U @ 10 mA/cm² refers to the operating voltage at 10 mA/cm². The lifetime LT is defined as the time after which the luminance drops from

25 the starting luminance to a certain proportion in the course of operation with constant current density. An LT90 figure means here that the lifetime reported corresponds to the time after which the luminance has dropped to 90% of its starting value. The figure @80 mA/cm² means here that the lifetime in question is measured at 80 mA/cm².

35 Foreignfiling Text P24-169

5

15

20

25

35 Foreignfiling Text P24-169

-60-

5

10

15

20

25

30

35 Foreignfiling Text P24-169

- 61 -

The structures, that are used in the devices with a first and a second electron blocking layer are shown in the following table:

5

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1) Inventive OLEDs containing a compound of the formula (I) in the EBL of greenphosphorescing OLEDs

25 Devices as shown in the following table are produced:

Table 2: Structure of the OLEDs

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In the device setup shown above, the compounds of the invention give good voltages for the OLEDs and better efficiencies and in case of HT-B as EBL a superior lifetime compared to the comparison example CE1 :

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Additional example with a first and a second electron blocking layer are produced. The

25 devices have the following structure:

Table 4: Structure of the OLEDs

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In the device setup shown above, the compounds of the invention give good voltages and efficiencies for the OLEDs, while lifetime is improved compared to the comparison example CE2:

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Claims

Foreignfiling Text P24-169 - 64 - Patent Claims

1. Compound according to formula (1),

5 where the compound of formula (1) can be partially or fully deuterated and the

15 following applies to the variables and indices present in the formula:

Ar¹, Ar², Ar³, Ar⁴ are each independently an aromatic ring system with 6 to 30 aromatic ring atoms or a heteroaromatic ring system with 5 to 30 aromatic ring atoms, each of which can be can be substituted by one or more substituents R;

20 and where Ar¹, Ar², Ar³, Ar⁴ can be partially or fully deuterated;

R stands on each occurrence, identically or differently, for H, D, F, CN, a straightchain alkyl, alkoxy or thioalkyl group having 1 to 20 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 C atoms, each of which may

25 be substituted by one or more radicals R², where in the alkyl, alkoxy or thioalkyl groups mentioned above one or more H atoms may be replaced by D, F or CN, an aromatic ring system having 6 to 30 aromatic ring atoms or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which may in each case be substituted by one or more radicals R²; where two or more adjacent radicals R may be connected to each other to form a ring; and where R can be partially or fully deuterated;

R¹ stands on each occurrence, identically or differently, for a straight-chain alkyl group having 1 to 20 C atoms, a branched alkyl group having 3 to 20 C or a cyclic

35 alkyl group having 3 to 20 C atoms; each of which may be substituted by one or more radicals R², where in the alkyl groups mentioned above one or more H atoms may be replaced by D, F or CN; or two adjactent radicals R¹ form a fused Foreignfiling Text P24-169

- 65 - aliphatic ring on Ar²; and where R¹ or the fused aliphatic ring formed by two adjacent R¹ can be partially or fully deuterated;

5 R² stands on each occurrence, identically or differently, for H, D, F, CN, a straightchain alkyl 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 R², where in the alkyl, alkoxy or thioalkyl groups mentioned above one or more H atoms may be replaced by D; and where R² can be partially or fully deuterated. n is, identically or differently at each instance, 0, 1, 2, 3 or 4; m is 0, 1, 2 or 3;

15 p is 1, 2, 3 or 4.

2. Compound according to claim 1 , which is selected from the compounds of formula (2),

Formula (2) where the the compound of formula (2) can be partially or fully deuterated and the symbols and indices have the meanings as described in claim 1.

3. Compound according to claim 1 or 2, which is selected from the compounds of formulae (3) and (4),

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Formula (3) Formula (4)

15 where the compounds of formula (3) and (4) can be partially or fully deuterated, the index q is 0, 1 , 2, 3 or 4 and the other symbols and indices have the meanings as described in claim 1.

20 4. Compound according to one or more of the preceding claims, which is selected from the compounds of formulae (3-1) to (3-4), (4-1) to (4-8), Foreignfiling Text P24-169

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Formula (3-3) Formula (3-4)

Formula (4-1) Formula (4-2)

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Formula (4-3) Formula (4-4)

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Formula (4-5) Formula (4-6) Foreignfiling Text P24-169

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15 where the compounds can be partially or fully deuterated, where Ring R1 corresponds to a fused aliphatic ring formed by two adjactent radicals R¹ and the other symbols and indices have the meanings as described in claim 1.

20 5. Compound according to one or more of the preceding claims, characterised in that, Ar¹ and Ar⁴ stand, identically or differently, for an aromatic ring system with 6 to 18 aromatic ring atoms, which can be partially or fully deuterated and can be substituted by one or more substituents R, or a heteroaromatic ring system with 6 to 18 aromatic ring atoms comprising a dibenzofuran, dibenzothiophene or carbazole group, each of

25 which can be partially or fully deuterated and can be substituted by one or more substituents R.

6. Compound according to one or more of the preceding claims, characterised in that Ar¹ and Ar⁴ stand, identically or differently, for phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene, naphthyl, dibenzofuran, dibenzothiophene and carbazole, each of which can be partially or fully deuterated and/or substituted with one or more groups R, and Ar³ stands for phenyl, biphenyl, terphenyl, quaterphenyl, fluorene, spirobifluorene and naphthyl, each of which can be partially or fully deuterated and can substituted by one or more substituents R.

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7. Compound according to one or more of the preceding claims, selected from the compounds of formulae (3-1 a) to (4-8a),

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Formula (4-7a) Formula (4-8a)

15 where the compounds (3-1 a) to (4-8a) can be partially or fully deuterated, where Ring R1 corresponds to a fused aliphatic ring formed by two adjactent radicals R¹, and the other symbols and indices have the meanings as described in claim 1.

20 8. Compound according to one or more of the preceding claims, characterized in that R stands on each occurrence, identically or differently, for H, 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 R², an aromatic ring system having 6 to 12 aromatic ring atoms or heteroaromatic ring system having 6 to

25 12 aromatic ring atoms, which may in each case be substituted by one or more radicals R²; where two or more adjacent radicals R may be connected to each other to form a ring and where R can be partially or fully deuterated.

9. Compound according to one or more of the preceding claims, characterised in that:

30 R¹ is, identically or differently at each instance, selected from: straight-chain alkyl groups having 1 , 2, 3, 4 or 5 C atoms, which may be substituted by one or more radicals R²; branched alkyl groups having 3, 4 or 5 C atoms, which may be substituted by one or more radicals R²;

35 - cyclic alkyl groups having 5 or 6 C atoms, which may be substituted by one or more radicals R²; or two adjacent radicals R¹ form a fused aliphatic ring, Ring R1 , where Ring R1 is selected from the rings of formulae (Ring-1) to (Ring-7) below: Foreignfiling Text P24-169

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(Ring-5) (Ring-6) (Ring-7) where

G is the same or different at each instance and is C(R²)2, (R²)2C-C(R²)2, (R²)C=C(R²), O or S, where R² has the same meaning in claim 1 ; and where the dotted bonds

20 represent the sites of attachment to the atoms of the groups to which the two radicals R¹ bind, and where the alkyl groups mentioned above and Ring R1 can be partially or fully deuterated.

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10. Compound according to one or more of the preceding claims, characterised in that: R¹ is, identically or differently at each instance, selected from methyl, ethyl, propyl, isopropyl, butyl, s-butyl, isobutyl and t-butyl groups, which can be partially of fully deuterated.

11. Compound according to one or more of the preceding claims, characterized in that

Ar¹ and Ar⁴ are selected, identically or differently, from the structures (Ar-1) to (Ar-83),

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5 where the dotted bonds represent the sites of attachment to the N atom to which Ar¹ and Ar⁴ bind; where the structures (Ar- 1 ) to (Ar-83) can be partially or fully deuterated and where the structures (Ar-1) to (Ar-83) can be substituted by R, and where: R° stands on each occurrence, identically or differently, for H, D, a straight-chain alkyl group having 1 to 10 C atoms or a branched or cyclic alkyl group having 3 to 10 C

15 atoms, each of which may be substituted by one or more radicals R², where in the alkyl groups mentioned above one or more H atoms may be replaced by D or F, an aromatic ring system having 6 to 12 aromatic ring atoms or heteroaromatic ring system having 6 to 12 aromatic ring atoms, which may in each case be substituted by one or more radicals R²; where two or more adjacent radicals R° may be connected to

20 each other to form a ring; and where R° can be partially or fully deuterated.

12. Compound according to one or more of the preceding claims, characterised in that the compound is partially or fully deuterated and that the degree of deuteration is at least 20 %.

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13. Organic electroluminescent device comprising at least one or more compound according to one or more of claims 1 to 12.

14. Organic electroluminescent device according to claim 13, characterised in that it comprises at least one layer selected from hole injection layers, hole-transporting layers, electron-blocking layers, which comprises at least one compound according to one or more of claims 1 to 12.

15. Organic electroluminescent device according to claim 14, characterised in that it

35 comprises in the following sequence: a hole injection layer, a hole-transporting layer and an electron-blocking layer, and the electron-blocking layer comprises at least one compound according to one or more of claims 1 to 12. Foreignfiling Text P24-169

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16. Organic electroluminescent device according to claim 14 or 15, characterised in that it comprises in the following sequence: a hole injection layer, a hole-transporting layer and a first electron-blocking layer, a second electron-blocking layer and an emitting

5 layer, where the second electron-blocking layer is adjacent to the emitting layer and the second electron-blocking layer comprises at least one compound according to one or more of claims 1 to 12.

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