CN113024612A

CN113024612A - Metal complexes comprising azaborine carbene ligands and their use in OLEDs

Info

Publication number: CN113024612A
Application number: CN202110303023.XA
Authority: CN
Inventors: 曹建华; 姜坤; 程友文; 李程辉; 谢佩; 孙建波; 王学涛
Original assignee: Beijing Bayi Space LCD Technology Co Ltd
Current assignee: Beijing Bayi Space LCD Technology Co Ltd
Priority date: 2021-03-22
Filing date: 2021-03-22
Publication date: 2021-06-25

Abstract

The present invention relates to metal-carbene complexes comprising a central atom selected from iridium or platinum and an azaborine carbene ligand, organic light-emitting diodes comprising such complexes, light-emitting layers comprising at least one such metal-carbene complex, devices selected from lighting elements, stationary video display devices, mobile video display devices comprising such OLEDs, and the use of such metal-carbene complexes in OLEDs, for example as emitters, matrix materials, charge transport materials and/or charge or exciton blockers.

Description

Metal complexes comprising azaborine carbene ligands and their use in OLEDs

Technical Field

The present invention relates to the field of OLED (organic light emitting diode) technology. More particularly, it relates to metal-carbene complexes comprising a central atom selected from iridium and platinum and an azaborine carbene ligand, and to the use of such complexes in the field of OLED technology.

Background

Organic Light Emitting Diodes (OLEDs) utilize the ability of a material to emit light when excited by an electrical current. OLEDs are of particular interest as alternatives to cathode ray tubes and liquid crystal displays, producing flat panel display devices. Due to the very compact design and the inherently low power consumption, devices comprising OLEDs are particularly suitable for mobile applications, such as applications for wireless phones, laptops, etc. In addition, white OLEDs offer advantages compared to the illumination techniques known today, in particular a particularly high efficiency.

A large number of metal-carbene complexes which emit light when excited by an electric current are proposed in the prior art, for example WO2005/019373 discloses transition metal complexes with carbene ligands as emitters for OLEDs. The ligands of these transition metal complexes are preferably linked via metal-carbene bonds and via bonds between the metal atom and the aromatic group, but no complexes with azaborine carbene ligands are disclosed. Transition metal-carbene complexes are disclosed in WO2006/056418, WO2007/088093, WO2007/185981 and the like. The metal-carbene ligands are imidazole rings or aromatic fused imidazole rings, and no disclosure of complexes with azaborine carbene ligands is made.

Even though compounds showing electroluminescence in the visible region of the electromagnetic spectrum, more particularly in the blue region, are known, it is desirable to provide compounds having a long diode lifetime. In the context of the present invention, electroluminescence is understood to mean either electroluminescence or electrophosphorescence.

It is therefore an object of the present invention to provide alternative iridium and platinum complexes suitable for electroluminescence in the visible region of the electromagnetic spectrum, more particularly in the blue region, which enable the production of full-color displays and white OLEDs. It is a further object of the present invention to provide corresponding complexes which can be used as mixtures with host compounds (matrix materials) as emissive layers in OLEDs. It is a further object of the present invention to provide corresponding complexes with high quantum yields and high stability in diodes. The complexes should be useful as emitters, matrix materials, charge transport materials, especially hole transport materials, or charge blockers in OLEDs.

Disclosure of Invention

The present disclosure provides metal complexes comprising azaborine carbene ligands that exhibit enhanced phosphorescent quantum yields when used in OLEDs, particularly in the blue light emitting region, and are useful as emitter materials in OLED applications.

In order to achieve the purpose, the invention adopts the following technical scheme:

according to the present invention, these objects are achieved by providing a metal-carbene complex comprising an azaborine carbene ligand having the formula shown in formula (I):

wherein M is Ir or Pt;

n is an integer of 1,2 or 3;

R²、R³、R⁴、R⁵、R⁶、R⁷each independently selected from hydrogen, deuterium, a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 carbon atoms and/or heteroatoms, a group having a donor or acceptor action, and adjacent groups are optionally joined or fused to form a five-, six-or polycyclic ring;

R¹selected from linear or branched alkyl groups having 1 to 20 carbon atoms, cycloalkyl groups having 3 to 20 carbon atoms, substituted or unsubstituted aryl groups having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl groups having 5 to 30 carbon atoms and/or heteroatoms;

k is an uncharged monodentate or bidentate ligand;

l is a mono-or dianionic ligand, preferably a monoanionic ligand, which may be monodentate or bidentate;

x is 0, 1 or 2, and when x is 2, the K ligands may be the same or different;

y is 0, 1 or 2, and when y is 2, the L ligands may be the same or different.

According to the invention, when x and y are each 0, a homoleptic azaborine metal-carbene complex of the formula (I) is present. When x and y are 1 or 2, a heteroleptic metal-carbene complex of the formula (I) is present.

Unless otherwise indicated, in the context of the present invention, the terms aryl, unit or group, heteroaryl, unit or group, alkyl, unit or group and cycloalkyl, unit or group are each defined as follows:

aryl, unit or group is to be understood as meaning a group having a basic skeleton of 6 to 30 carbon atoms, preferably 6 to 18 carbon atoms, and formed by an aromatic ring or by a plurality of fused aromatic rings. Suitable basic skeletons are, for example, phenyl, naphthyl, anthryl or phenanthryl. The basic skeleton may be unsubstituted, which means that all substitutable carbon atoms carry a hydrogen atom, or may be substituted in one, more than one or all substitutable positions of the basic skeleton. Suitable substituents are, for example, alkyl groups, preferably alkyl groups having 1 to 8 carbon atoms, more preferably methyl, ethyl, isopropyl, tert-butyl, neopentyl. Aryl, preferably phenyl, which in turn may be substituted or unsubstituted. Heteroaryl, preferably heteroaryl comprising at least one nitrogen atom, more preferably pyridyl. The alkenyl group is preferably an alkenyl group having one double bond, more preferably an alkenyl group having one double bond and 1 to 8 carbon atoms, or a group having a donor or acceptor action. A group having a donor action is understood to mean a group having a + I and/or + M effect, and a group having an acceptor action is understood to mean a group having an-I and/or-M effect. Suitable groups having donor or acceptor action are halogens, preferably F, Cl, Br, more preferably F, alkyl groups, silyl groups, siloxy groups, alkoxy groups, aryloxy groups, carbonyl groups, ester groups, amine groups, amide groups, CH₂F group, CHF₂Radical, CF₃A group, a CN group, a sulfur-containing group, or a SCN group. Aryl most preferably carries a group selected from methyl, ethyl, isoPropyl, n-butyl, isobutyl, tert-butyl, neopentyl, CF₃Aryloxy, amine, sulfur containing groups and alkoxy substituents, or aryl is unsubstituted. The aryl or aryl group is preferably phenyl optionally substituted with at least one substituent as described above. The phenyl group more preferably has 0, 1,2 or 3 of the above substituents.

Heteroaryl or heteroaryl unit or group is understood as meaning a group having 5 to 30 carbon atoms and/or heteroatoms, which differs from the abovementioned aryl groups in that at least one carbon atom is replaced by a heteroatom in the basic skeleton of the aryl group. Preferred heteroatoms are N, O and S. Most preferably, one or two carbon atoms of the basic skeleton of the aryl group are substituted with a heteroatom. The basic skeleton is particularly preferably selected from electron-poor systems such as pyridyl, pyrimidinyl, pyrazolyl and triazolyl, and five-membered heteroaromatic compounds such as pyrrole, furan, thiophene, imidazole, pyrazole, triazole, oxazole and thiazole. The base skeleton may be substituted at one, more than one, or all of the substitutable positions of the base skeleton. Suitable substituents are the same as described for aryl.

Alkyl or alkyl group is understood to mean a group having from 1 to 20 carbon atoms, preferably from 1 to 10 carbon atoms, more preferably from 1 to 8 carbon atoms. The alkyl group may be branched or unbranched and may optionally be interrupted by one or more heteroatoms, preferably N, O or S or substituted by halogen atoms, for example fluorine. In addition, the alkyl group may be substituted with one or more substituents as described for the aryl group. Likewise, an alkyl group may carry one or more aryl groups. All of the above aryl groups are suitable. Particular preference is given to alkyl radicals selected from the group consisting of methyl, ethyl, isopropyl, n-propyl, isobutyl, n-butyl, tert-butyl, sec-butyl, isopentyl, n-pentyl, sec-pentyl, neopentyl, n-hexyl, isohexyl and sec-hexyl. Very particular preference is given to methyl, isopropyl, tert-butyl and neopentyl.

Cycloalkyl or cycloalkyl radicals are to be understood as meaning cyclic radicals having from 3 to 20 carbon atoms, preferably from 3 to 10 carbon atoms, more preferably from 3 to 8 carbon atoms. The cycloalkyl group may optionally be interrupted by one or more heteroatoms, preferably N, O or S. In addition, the cycloalkyl group may be unsubstituted or substituted, i.e., may be substituted with one or more substituents as described for aryl. Cycloalkyl groups may likewise carry one or more aryl groups. All of the above aryl groups are suitable.

According to the invention, the statements made with respect to aryl, heteroaryl, alkyl and cycloalkyl independently apply to the radicals mentioned in the application, in particular to the radical R¹、R²、R³、R⁴、R⁵、R⁶And R⁷。

K in formula (I) is an uncharged monodentate or bidentate ligand and L in formula (I) is a mono-or dianionic ligand, preferably a monoanionic ligand, which may be monodentate or bidentate.

The bidentate ligand is understood to mean a ligand which is coordinated in two positions to the transition metal atom M. Monodentate ligands are understood to mean ligands which are coordinated to the transition metal atom M in one position of the ligand. Suitable mono-or dianionic ligands L, which may be monodentate or bidentate, preferably monoanionic ligands, are the ligands usually used as monodentate or bidentate mono-or dianionic ligands. Suitable monoanionic monodentate ligands are, for example, halogens, in particular Cl^-And Br^-Pseudohalides, understood to mean CN, SCN and OCN, in particular CN^-Cyclopentadienyl (Cp)^-) Cyanides, alkyl radicals such as CH bound to the transition metal M by a bond₃An alkylaryl group such as benzyl attached to the transition metal M by a bond. Suitable monoanionic bidentate ligands are, for example, acetylacetonate and its derivatives, picolinate, Schiff bases, amino acids, arylpyridines such as phenylpyridine, or further bidentate monoanionic ligands as described in WO02/15645, carbene ligands as described in WO2006056418 and EP1658343, arylazoles such as 2-arylimidazoles, preferably 2-arylimidazoles and carbene ligands. Suitable dianionic bidentate ligands are, for example, dialkoxides, bicarbonates, dicarboxylates, diamides, diimides, dithiolates, biscyclopentadienyl, bisphosphonates, bissulfonates and 3-phenylpyrazoles. Suitable uncharged monodentate or bidentate ligands K are preferably selected from phosphines, mono-and bisphosphines; phosphates, mono-and bisphosphonates, and derivatives thereof, arsenates, mono-and bis-arsenates, and derivatives thereof; aPhosphates, mono-and diphosphites; CO; pyridine, mono-and bipyridine; nitriles, dinitriles, allyls, diimines, and M¹Non-conjugated dienes and conjugated dienes that form pi complexes. Particularly preferred charged monodentate or bidentate ligands K are selected from the group consisting of phosphines, mono-and bisphosphines, preferably trialkyl, triaryl or alkylaryl phosphines, more preferably PAr₃Wherein Ar is substituted or unsubstituted aryl and PAr₃The three aryl groups in (A) may be the same or different, more preferably PPh₃、PEt₃、PⁿBu₃、PEt₂Ph、PMe₂Ph、PⁿBu₂Ph; phosphonates and their derivatives, arsenates and their derivatives, sulfites, CO; pyridine, mono-and bipyridine, wherein the pyridine may be substituted with alkyl or aryl; nitriles and with M¹Dienes forming pi complexes, preferably eta⁴-diphenyl-1, 3-butadiene,. eta⁴-1, 3-pentadiene eta⁴-1-phenyl-1, 3-pentadiene eta⁴-1, 4-dibenzyl-1, 3-butadiene,. eta⁴-2, 4-hexadiene,. eta⁴-3-methyl-1, 3-pentadiene eta⁴-1, 4-xylyl-1, 3-butadiene,. eta⁴-1, 4-bis (trimethylsilyl) -1, 3-butadiene and η²-or η⁴Cyclooctadiene (1, 3 each and 1,5 each), more preferably 1, 4-diphenyl-1, 3-butadiene, 1-phenyl-1, 3-pentadiene, 2, 4-hexadiene, butadiene,. eta.²Cyclooctene,. eta.⁴-1, 3-cyclooctadiene and η⁴-1, 5-cyclooctadiene. Very particularly preferred uncharged monodentate ligands are selected from PPh₃、P(OPh)₃、AsPh₃CO, pyridine, nitrile and derivatives thereof. Suitable uncharged mono-or bidentate ligands are preferably 1, 4-diphenyl-1, 3-butadiene, 1-phenyl-1, 3-pentadiene, 2, 4-hexadiene,. eta.⁴-cyclooctadiene and η²Cyclooctadiene (1, 3 respectively and 1,5 respectively).

In the above case, the number of monoanionic ligands L is 0, 1, 2. When y >1, the L ligands may be the same or different, preferably the same. The number x of uncharged ligands K depends on whether the coordination number 6 of Ir (III) or 4 of Pt (II) has been achieved by means of carbene ligands and ligands L. In the case of Ir (III), when n is 3 and three monoanionic bidentate carbene ligands are used, x is 0 in the above case. In the case of Pt (II), when n is 2 and two monoanionic bidentate carbene ligands are used, x is in this case likewise 0.

In a further preferred embodiment, the present invention relates to a metal-carbene complex, wherein L in formula (I) is a ligand represented by formula (II):

wherein R is⁸、R⁹、R¹⁰、R¹¹、R¹²、R¹³、R¹⁴Each independently selected from hydrogen, deuterium, a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a heterocycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 carbon atoms and/or heteroatoms, a group having a donor or acceptor action, adjacent groups being optionally joined or fused to form a five-, six-or polycyclic ring;

and R is⁸Cannot be hydrogen or deuterium;

a — represents a bond to the metal M.

Very particularly preferred ligands L according to the invention are the following:

according to the present invention, preferably, M is Ir or Pt, more preferably Ir. Ir is present in the complex of the present invention in the +3 oxidation state. Pt is present in the complexes of the present invention in the +2 oxidation state. n is typically 1,2 or 3. If M is Ir, n is preferably 3. If M is Pt, n is preferably 1.

More preferably, the present invention relates to a metal-carbene complex according to the invention, wherein M is Ir, n is an integer of 1,2 or 3;

R²、R³、R⁴、R⁵、R⁶、R⁷each independently selected from hydrogen, deuterium, a linear or branched alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 carbon atoms and/or heteroatoms, and adjacent groups are optionally joined or fused to form a five-, six-or polycyclic ring;

l is a monoanionic bidentate ligand;

x is 0;

y is 0, 1 or 2.

According to the invention, particularly preferred metal-carbene complexes of the formula (I) according to the invention are the following:

the homoleptic metal-carbene complexes according to the invention may exist in the form of a facial or meridional isomer, preference being given to the facial isomer.

In the case of heteroleptic metal-carbene complexes, four different isomers, preferably pseudofacial isomers, may be present.

In addition, the present invention relates to a process for preparing the metal-carbene complexes according to the invention by contacting suitable compounds comprising M with suitable ligands or ligand precursors.

In a preferred embodiment of the process of the invention, a suitable compound comprising a suitable metal M, i.e. iridium or platinum, preferably iridium, is reacted with a suitable carbene ligand, preferably in deprotonated form, as a free carbene or in protected carbene form, for example as a silver-carbene complex.

In a further preferred embodiment of the process according to the invention, the ligand precursor used is an organic compound which is reacted with a suitable M-containing compound. The carbene may be released from the precursor of the carbene ligand by removing volatile substances, e.g. methanol, ethanol, at elevated temperature and/or at reduced pressure and/or using molecular sieves of the alcohol molecule with eliminated adhesion. Corresponding methods are known to the person skilled in the art.

The metal-carbene complexes and mixtures thereof according to the invention are outstandingly useful as emitters in organic light-emitting diodes. The variation of the ligands makes it possible to provide corresponding complexes which exhibit electroluminescence in the red, green and, in particular, the blue region of the electromagnetic spectrum. The complexes of the invention are therefore outstandingly suitable as emitter substances, since they have an emission in the visible region of the electromagnetic spectrum, for example 400 to 800nm, preferably 400 to 600 nm. The complexes of the invention make it possible to provide compounds which have electroluminescence in the red, green and blue region of the electromagnetic spectrum. Thus, industrially useful OLEDs can be provided by means of the complexes of the invention as emitter substances.

In addition, the metal-carbene complexes of the formula (I) according to the invention are suitable as matrix materials, charge transport materials, in particular hole transport materials, and/or charge blockers.

The metal-carbene complexes of the formula (I) according to the invention are preferably suitable as emitters and/or hole transport materials, more preferably as emitters.

The special properties of the metal-carbene complexes of the formula (I) according to the invention are particularly good efficiency and long life when used in OLEDs.

The present application therefore further provides OLEDs which comprise at least one metal-carbene complex of the formula (I) according to the invention. The metal-carbene complexes of the formula (I) according to the invention are preferably used as emitters, matrix materials, charge transport materials, in particular hole transport materials, and/or hole blockers in OLEDs, more preferably as emitters and/or hole transport materials, particularly preferably as emitters.

The present application also provides for the use of the metal-carbene complexes of the formula (I) as light-emitting layer, preferably as emitter, matrix material, charge transport material, in particular hole transport material, and/or charge blocker, more preferably as emitter and/or hole transport material, particularly preferably as emitter, in OLEDs.

The metal-carbene complexes of the formula (I) used according to the invention can be present in the light-emitting layer in bulk, i.e. without further addition. However, it is also possible for other compounds to be present in the light-emitting layer in addition to the metal-carbene complexes of the formula (I) used according to the invention. For example, fluorescent dyes may be present to alter the emission color of the metal-carbene complex used as an emitter molecule. In addition, a diluent material (matrix material) may be used. The diluent material may be a polymer, such as poly (N-vinylcarbazole) or polysilane. However, the diluent material may also be a small molecule, such as 4,4 '-N, N' -dicarbazole biphenyl or an aromatic amine. When a diluent material is used, the metal-carbene complexes of the formula (I) according to the invention are used in the light-emitting layer in general in an amount of less than 40% by weight, preferably from 3 to 30% by weight. The metal-carbene complexes of the formula (I) according to the invention are preferably used in the matrix. The light-emitting layer therefore preferably comprises at least one metal-carbene complex of the formula (I) according to the invention and at least one matrix material.

Suitable matrix materials, in addition to the abovementioned diluent materials, are in principle the materials described below as hole-and electron-transporting materials and also carbon complexes, for example carbene complexes of the formula (I) and also other carbene complexes. Particularly suitable are carbazole derivatives, such as 4,4' -bis (carbazol-9-yl) -2,2' -dimethylbiphenyl, 4' -bis (carbazol-9-yl) biphenyl, 1, 3-bis (N-carbazolyl) benzene, in a particularly preferred embodiment one or more compounds of formula (III) described below are used as matrix material. Preferred embodiments of the compounds of the formula (III) are likewise described below.

The invention also relates to an organic light emitting diode according to the invention comprising an electron transport layer comprising at least two different materials, wherein at least one of the materials should be electron conducting. Preferably, in such a mixed electron transport layer, at least one phenanthroline compound, or at least one phenanthroline derivative and/or pyridine derivative is used. More preferably, in the mixed electron transport layer, an alkaline earth metal or alkali metal quinolinol complex such as lithium 8-quinolinol is used in addition to at least one phenanthroline compound.

The OLEDs of the present invention can be produced by methods known to those skilled in the art. In general, an organic light emitting device includes at least one organic layer disposed between and electrically connected to an anode and a cathode. Fig. 1 shows a schematic diagram of an organic light emitting device 100. The illustrations are not necessarily drawn to scale. Device 100 can include substrate 110, anode 115, hole injection layer 120, hole transport layer 125, electron blocking layer 130, light emitting layer 135, hole blocking layer 140, electron transport layer 145, electron injection layer 150, protective layer 155, cathode 160, and barrier layer 170. Cathode 160 is a composite cathode having a first conductive layer 162 and a second conductive layer 164. The device 100 may be fabricated by sequentially depositing the described layers.

Fig. 2 shows a schematic view of an inverted organic light emitting device 200. The device comprises a substrate 210, a cathode 215, a light-emitting layer 220, a hole transport layer 225, and an anode 230. The device 200 may be prepared by sequentially depositing the described layers. Because the most common OLED device has a cathode disposed over an anode, and device 200 has cathode 215 disposed under anode 230, device 200 can be referred to as an "inverted" organic light emitting device. In the corresponding layers of the device 200, materials similar to those described with respect to the device 1 may be used. Fig. 2 provides one example of how some layers may be omitted from the structure of device 100.

The simple layered structure illustrated in fig. 1 and 2 is provided as a non-limiting example, and it should be understood that embodiments of the present invention can be used in conjunction with a wide variety of other structures. The particular materials and structures described are exemplary in nature, and other materials and structures may be used. A functional OLED may be realized by combining the various layers described in different ways, or several layers may be omitted altogether, based on design, performance and cost factors. Other layers not specifically described may also be included. Materials other than those specifically described may be used. Although many of the examples provided herein describe the various layers as comprising a single material, it will be understood that combinations of materials may be used, such as mixtures of a host and a dopant, or more generally, mixtures. Also, the layer may have various sub-layers. The names given to the various layers herein are not intended to be strictly limiting. For example, in device 200, hole transport layer 225 transports holes and injects holes into light emitting layer 220, and may be described as a hole transport layer or a hole injection layer. In one embodiment, an OLED may be described as having an organic layer disposed between a cathode and an anode. This organic layer may comprise a single layer or may further comprise multiple layers of different organic materials as described in fig. 1 and 2.

Structures and materials not specifically described, such as PLEDs comprising polymeric materials, may also be used. As another example, OLEDs having a single organic layer or multiple stacks may be used. The OLED structure may deviate from the simple layered structure illustrated in fig. 1 and 2. For example, the substrate may include an angled reflective surface to improve optical coupling.

Any of the layers of the various embodiments may be deposited by any suitable method, unless otherwise specified. For organic layers, preferred methods include thermal evaporation, organic vapor deposition methods, or application of one or more layers by means of carrier gas sublimation, where at 10^-5The material is applied at a pressure between mbar and 1 bar. A particular example of this method is the organic vapour jet printing method, in which the material is applied directly through a nozzle and is therefore structured. Other suitable deposition methods include creating one or more layers, for example by spin coating, or by any desired printing method, such as screen printing, flexographic printing, lithography, photo-induced thermal imaging, thermal transfer, ink jet printing, or nozzle printing. Soluble compounds, for example obtained by appropriate substitution. These methods are also particularly suitable for oligomers, dendrimers and polymers. Furthermore, hybrid methods are possible, in which, for example, one or more layers are applied from solution and one or more further layers are applied by vapor deposition.

In any of the above-mentioned compounds used in each layer of the above-mentioned OLED devices, the hydrogen atoms may be partially or fully deuterated. Thus, any of the specifically listed substituents, such as (but not limited to) methyl, phenyl, pyridyl, and the like, can be in their non-deuterated, partially deuterated, and fully deuterated forms. Similarly, substituent classes (such as, but not limited to, alkyl, aryl, cycloalkyl, heteroaryl, etc.) can also be non-deuterated, partially deuterated, and fully deuterated forms thereof.

The materials and structures described herein can be applied in devices other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors may use the materials and structures. Further, organic devices such as organic transistors may use the materials and structures.

In a preferred embodiment, the present invention relates to an OLED comprising at least one metal-carbene complex of the formula (I) according to the invention and at least one compound of the formula (III):

wherein T is NR¹⁷S, O or PR¹⁷；

Q is-NR¹⁸R¹⁹、-PR¹⁸R¹⁹、-P(O)R¹⁸R¹⁹、-S(O)₂R¹⁸、-S(O)R¹⁸、-SR¹⁸、-SiR¹⁷R¹⁸R¹⁹OR-OR¹⁸；

R¹⁵、R¹⁶、R¹⁷、R¹⁸、R¹⁹Each independently selected from hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl, or R¹⁸、R¹⁹Together with the nitrogen atom, form a cyclic group having 3 to 10 ring atoms, which may be unsubstituted or substituted by one or more substituents selected from the group consisting of alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl and a group having donor action, and/or may be fused with one or more other cyclic groups having 3 to 10 ring atoms, wherein the fused group may be unsubstituted or substituted by one or more substituents selected from the group consisting of alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl and a group having donor or acceptor action;

a is an integer of 0-4;

b is an integer of 0 to 3;

the two units of formula (III) are bridged to each other by means of a linear or branched, saturated or unsaturated bridge, optionally interrupted by at least one heteroatom, by means of a bond or by means of O, S.

The group T in the compound of formula (III) is NR¹⁷S, O or PR¹⁷Preferably NR¹⁷S or O, more preferably O or S, most preferably O.

The compounds of the formula (III) can be used in combination with the claimed complexes as matrix (diluent material), hole/exciton blocker, electron transport material or hole transport material, the complexes then preferably being used as emitters. The OLEDs of the invention which comprise at least one compound of the formula (III) and one compound of the formula (I) exhibit particularly good efficiency and lifetime. Depending on the function of the compound of the formula (III) used, it is present in pure form or in different mixing ratios. In a particularly preferred embodiment, one or more compounds of the formula (III) are used as matrix material in the light-emitting layer.

According to the invention, it is also possible to use, in addition to the compounds of the formula (III), crosslinked or polymeric materials which comprise recurring units based on the general formula (III), in crosslinked or polymerized form together with at least one metal-carbene complex of the general formula (I). Like the compounds of the formula (III), the latter are preferably used as matrix materials.

Crosslinked or polymeric materials have significant solubility in organic solvents, excellent film forming properties, and relatively high glass transition temperatures. In addition, high charge carrier mobilities, high color emission stability and long operating times of the corresponding components are observed when the crosslinked or polymeric materials of the invention are used in Organic Light Emitting Diodes (OLEDs).

In a further preferred embodiment of the inventive OLED, it comprises an emission layer comprising at least one metal-carbene complex of the general formula (I) according to the invention, at least one matrix material of the formula (III) and optionally at least one further hole-transporting matrix material.

The OLEDs of the invention can be used in all devices where electroluminescence is useful. Suitable devices are preferably selected from stationary and mobile video display devices and lighting means. The invention therefore also relates to a device comprising an OLED according to the invention, selected from stationary and mobile video display devices and lighting means.

Stationary video display devices are, for example, video display devices of computers, televisions, video display devices in printing presses, kitchen appliances and billboards, lighting devices and information boards. Mobile video display devices are for example radio telephones, laptops, digital cameras, mp3 players, smartphones, video display devices in vehicles, and destination displays on buses and trains.

In addition, the metal-carbene complexes of the general formula (I) according to the invention can be used in OLEDs having an inverted structure. In these inverted OLEDs, for example as described in FIG. 2, the complexes according to the invention are in turn preferably used in the light-emitting layer. The structure of an inverted OLED and the materials typically used therein are known to those skilled in the art.

The present invention further provides white OLEDs which comprise at least one metal-carbene complex of the general formula (I) according to the invention. In a preferred embodiment, the metal-carbene complexes of the general formula (I) are used as emitter materials in white OLEDs. Preferred embodiments of the metal-carbene complexes of the general formula (I) are as described hereinbefore. In addition to the at least one metal-carbene complex of the general formula (I), the white OLED may comprise:

(i) at least one compound of formula (III). The compounds of the formula (III) are preferably used as matrix materials. Preferred compounds of formula (III) are as hereinbefore described; and/or

(ii) At least one electron transport material. Preferably at least one phenanthroline derivative and/or pyridine derivative.

To obtain white light, OLEDs must produce light that renders the entire visible range of the spectrum. However, organic emitters typically emit only a limited portion of the visible spectrum. White light can be produced by a combination of different emitters. Typically, red, green and blue emitters are combined. However, the prior art also discloses other methods for forming white OLEDs, such as triple harvesting routes. Structures suitable for or methods of forming white OLEDs are known to those skilled in the art.

In one embodiment of a white OLED, several dyes are layered one on top of the other in the light emitting layer of the OLED and thus combined (layered device). This can be achieved by mixing all dyes or by directly connecting different color layers in series. The expression "layered OLED" and suitable embodiments are known to the person skilled in the art.

In another embodiment of this "stacked device concept", it is also possible to stack only two OLEDs or more than three OLEDs.

In another embodiment of a white OLED, the light source white light can also be combined to produce the two concepts mentioned. For example, a single color OLED (e.g., blue) may be stacked with a multi-color layered OLED (e.g., red-green). Other combinations of the two concepts are possible and known to those skilled in the art.

The metal-carbene complexes of the formula (I) according to the invention can be used in any of the above-mentioned layers in white OLEDs. In a preferred embodiment, it is used in one or more or all light-emitting layers of an OLED, in which case the structure of the metal-carbene complexes of the invention varies with the use of the complex. Suitable and preferred components for the other layers of the photo-OLED or materials suitable as matrix material and preferred matrix material in the light-emitting layer are likewise described above.

The invention also relates to an organic electronic component, preferably an organic light-emitting diode (OLED), an organic photovoltaic cell (OPV), an Organic Field Effect Transistor (OFET) or a light-emitting electrochemical cell (LEEC), comprising a metal-carbene complex according to the general formula (I) according to the invention.

The following examples, and more particularly the methods, materials, conditions, process parameters, equipment, etc., detailed in the examples, are intended to support the present invention, but not to limit the scope of the invention.

All experiments were performed under a protective gas atmosphere.

Drawings

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

Fig. 1 shows a schematic diagram of an organic electroluminescent element in an embodiment of the present invention.

Fig. 2 shows a schematic view of an inverted organic electroluminescent element in an embodiment of the present invention.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that the upper and lower limits of the range, and each intervening value therebetween, is specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control. Unless otherwise indicated, "%" is percent by weight.

"EQE" in the present invention refers to the external quantum efficiency of the device, i.e., the ratio of the number of photons emitted by the device to the number of electrons injected into the device.

By "LE" in the present invention is meant lumen efficiency, i.e. the ratio of the emitted luminous flux to the input electrical power upon excitation.

The "lifetime T95" in the present invention means the time required for the luminance of the element to decay to 90% of the initial luminance.

Examples

In the following examples of the present invention, a conventional production method is employed unless otherwise specified. The starting materials used are commercially available from published sources unless otherwise specified.

In order to illustrate the present invention more clearly, the following description will be made with reference to some specific examples:

in the embodiment of the invention, the performance detection conditions of the prepared electroluminescent device are as follows:

luminance and chromaticity coordinates: testing with a photosresearch PR-715 spectrum scanner;

current density and lighting voltage: testing using a digital source table Keithley 2420;

power efficiency: tested using NEWPORT 1931-C.

Example 1

Preparation of compound P10:

the first step is as follows: preparation of Compound int. -1

3.8g (50.0mmol) of acetylene dicyan is dissolved in 100mL of n-heptane, 6.6g (50.0mmol) of 2,4, 6-trimethylphenylborane is added under the protection of nitrogen, the mixture is stirred at room temperature for 4 hours, 5.2g (50.0mmol) of phenylisonitrile is stirred at room temperature for 2 days, the mixture is concentrated under reduced pressure to dryness, and the dryness is separated and purified by a silica gel column, so that an intermediate int. -1 is obtained, namely a yellow solid, and the yield is 93%.

The second step is that: preparation of Compound int. -2

12.5g (40.0mmol) of intermediate int. -1 are dissolved in 100mL of chloroform, 4.9g (40.5mmol) of benzoic acid are added under nitrogen protection, the reaction is stirred at room temperature for 1 hour, the mixture is filtered, and the filter cake is washed with petroleum ether to obtain intermediate int. -2 which is white solid and has a yield of 100%.

The third step: preparation of Compound int. -3

17.2g (40.0mmol) of intermediate int. -2 are dispersed in 150mL acetonitrile, 44.5g (120.0mmol) of tetrabutylammonium iodide are added, the reaction is stirred at room temperature for 24 hours under nitrogen protection, filtered, and the filter cake is washed with petroleum ether to give compound int. -3 as a white solid in 76% yield.

The fourth step: preparation of Compound P10

4.4g (10.0mmol) of intermediate int. -3 are dispersed in 80mL of 1, 4-dioxane, 2.2g (9.5mmol) of silver oxide and 10g of molecular sieve are added, the reaction is stirred at room temperature overnight under nitrogen protection, 672.5mg (1.0mmol) of chloro (1, 5-cyclooctadiene) iridium (I) dimer is added, the reaction is refluxed at elevated temperature overnight, cooled to room temperature, filtered, and the filter cake is washed with n-hexane to give compound P10 in 92% yield.

¹HNMR(DMSO-d₆,300MHz,100℃)：δ＝7.93～7.90(d,3H),7.50～7.46(m,3H),6.95～6.91(m,3H),6.86～6.83(m,3H),6.81(s,6H),2.38(s,18H),2.23(s,9H)。

Example 2

Preparation of compound P15:

the first step is as follows: preparation of compound int

Compound int. -4 was prepared as a yellow solid in 95% yield by replacing only acetylene dicyanide of the first step of example 1 with 1, 2-di-p-toluenesulfonylacetylene with reference to the preparation of the first step of example 1.

The second step is that: preparation of Compound int. -5

11.4g (20.0mmol) of intermediate int. -4 is dissolved in 80mL of acetonitrile, 1.5g (24.0mmol) of ethylenediamine and 5mL of triethylamine are added, the mixture is heated to reflux and stirred for reaction for 2 hours, the mixture is cooled to room temperature, the mixture is concentrated under reduced pressure and dried, the mixture is dissolved in 100mL of toluene, the mixture is filtered, filtrate is washed twice by dilute hydrochloric acid aqueous solution, organic phase is collected and dried, the mixture is concentrated under reduced pressure and dried, 100mL of xylene and 17.5g of manganese dioxide are added, the mixture is heated to reflux and stirred for reaction for 24 hours, the mixture is cooled to room temperature, the filter cake is washed by toluene, the filtrate is concentrated under reduced pressure and dried, and the mixture is separated and purified by a silica gel column, so that intermediate int. -5.

The third step: preparation of Compound int. -6

Compound int. -6 was prepared as a yellow solid with a yield of 98% by replacing int. -1 of the second step of example 1 with int. -5, with reference to the preparation of the second step of example 1.

The fourth step: preparation of Compound int. -7

Referring to the preparation method of the third step of example 1, compound int. -7 was prepared in a white solid with a yield of 72% by replacing int. -2 of the third step of example 1 with int. -6.

The fifth step: preparation of Compound P15

Compound P15 was prepared in 78% yield by replacing int. -3 of the fourth step of example 1 with int. -7, according to the preparation method of the fourth step of example 1.

¹HNMR(DMSO-d₆,300MHz,100℃)：δ＝8.66～8.64(m,3H),8.44～8.42(m,3H),7.65～7.62(d,3H),7.29～7.24(t,3H),6.91～6.87(t,3H),6.70(s,6H),6.59～6.56(m,3H),2.33(s,18H),2.21(s,9H)。

Example 3

Preparation of compounds P01-P09, P11-P14 and P16-P48:

referring to the preparation methods of example 1 and example 2, compounds represented by formulas P01 to P09, P11 to P14, and P16 to P48 were prepared.

Example 4

Preparation of compound P65:

the first step is as follows: preparation of Compound int. -8

4.3g (18.5mmol) of silver oxide, 9.5g (33.1mmol) of 1-phenyl-3-methylimidazolium iodide salt and 3.5g (10.1mmol) of iridium trichloride hydrate are dispersed in 150mL of ethylene glycol ether, the reaction is stirred at reflux for 16 hours under heating, cooled to room temperature, filtered, and the filter cake is washed with methanol to obtain an intermediate int. -8 as a yellow solid with a yield of 62%.

The second step is that: preparation of Compound P65

812mg (1.5mmol) of intermediate int. -9 (prepared according to the synthesis method of the first step in example 1) was dispersed in 50mL of dry 1, 4-dioxane, under the protection of nitrogen, 280mg (1.2mmol) of silver oxide and 5g of molecular sieve were added, the mixture was stirred at room temperature for 12 hours, 0.4g (0.37mmol) of intermediate int. -8 prepared in the previous step and 50mL of xylene were added, the mixture was heated under reflux and stirred for 5 hours, cooled to room temperature, filtered, and the filter cake was washed with dilute hydrochloric acid, water and ethanol to obtain product P65 as a yellow solid with a yield of 42%.

¹HNMR(DMSO-d₆,300MHz,100℃)：δ＝8.48～8.46(m,2H),7.90～7.87(m,3H),7.56～7.33(m,15H),7.09(s,2H),6.96～6.94(d,2H),6.78～6.76(d,2H),2.73(s,6H),2.26(s,6H),2.22(s,3H)。

Example 5

Preparation of compounds P52-P64, P66-P124, P144, P145, P165-P202, P226-P232:

referring to the preparation method of example 4, compounds represented by formulas P52 to P64, P66 to P124, P144, P145, P165 to P202, and P226 to P232 were prepared.

Example 6

Preparation of compound P162:

the first step is as follows: preparation of Compound int. -10

5.0g (14.0mmol) of benzimidazole tetrafluoroborate is dispersed in 120mL of toluene, the temperature is reduced to-8 ℃ by an ice salt bath under the protection of nitrogen, 28mL of 0.5M bis (trimethylsilyl) amino potassium is added dropwise, the mixture is heated to room temperature and stirred for reaction for 1 hour, the temperature is reduced to-78 ℃ by liquid nitrogen, 4.7g (7.0mmol) of bis (1, 5-cyclooctadiene) iridium (I) chloride dimer is added in batches, the mixture is heated to room temperature and stirred for reaction for 2 hours, the mixture is heated to reflux for reaction for 20 hours, the mixture is cooled to room temperature and filtered, a filter cake is washed by toluene, and the filtrate is concentrated under reduced pressure to obtain a compound int-10, a yellow solid and the yield is 75%.

The second step is that: preparation of Compound P162

4.1g (7.9mmol) of intermediate int. -11 (prepared according to the first synthesis step in example 1) was dispersed in 140mL of 1, 4-dioxane, 1.5g (6.3mmol) of silver oxide and 15g of molecular sieve were added under nitrogen protection, the mixture was stirred at room temperature for 16 hours, 1.6g (2.6mmol) of the intermediate int. -10 solution prepared in the previous step in 200mL of xylene was slowly added dropwise, after dropping, the mixture was heated under reflux and stirred for 24 hours, cooled to room temperature, filtered, the filtrate was concentrated under reduced pressure and dried, and the filtrate was dispersed in ether and filtered to obtain P162 as a yellow solid with a yield of 46%.

¹HNMR(DMSO-d₆,300MHz,100℃)：δ＝7.78～7.75(m,2H),7.64～7.62(m,1H),7.44～7.40(m,3H),7.22～7.15(m,7H),7.09～7.01(m,8H),6.83～6.81(d,2H),6.73～6.70(m,2H),2.28(s,12H),2.21(s,6H)。

Example 7

Preparation of Compounds P125-P143, P146-P161, P163, P164, P203-P225:

compounds represented by the formulae P125 to P143, P146 to P161, P163, P164 and P203 to P225 were prepared by the preparation method of example 6.

(preparation of organic electroluminescent element)

Example 8

The glass substrate coated with the ITO conductive layer is subjected to ultrasonic treatment in a cleaning agent for 30 minutes, washed in deionized water, subjected to ultrasonic treatment in an acetone/ethanol mixed solvent for 30 minutes, baked to be completely dry in a clean environment, irradiated by an ultraviolet light cleaning machine for 10 minutes, and bombarded on the surface by a low-energy cation beam.

Placing the processed ITO glass substrate in a vacuum chamber, and vacuumizing to 1 × 10^-5～9×10^-3Pa, continuously and respectively evaporating a compound DNTPD as a hole injection layer on the anode layer film to a film thickness of

Continuously depositing NPB on the hole injection layer film to form a hole transport layer, wherein the deposition film has a thickness of

A layer of HT01 is evaporated on the hole transport layer to form an electron blocking layer of the device, and the thickness of the evaporated layer is set to

An organic light-emitting layer containing a metal complex (see the "metal complex" column in table 2 below) and SC1 as elements was further deposited on the electron blocking layer, wherein SC1 was a host material and the compound of the present invention was a dopant, the dopant concentration was the value indicated in parentheses in the "metal complex" column in table 2 below, and the deposition film thickness was the thickness indicated in the parentheses

And further evaporating a LiQ layer and an ET010 layer on the organic light-emitting layer to form an electron transport layer of the element, wherein the LiQ is 60% of the mass of the ET010, and the thickness of the evaporated film is equal to

Depositing a layer of LiF on the luminescent layer as deviceAn electron injection layer having a thickness of

Finally, metal aluminum is evaporated on the electron injection layer to form a cathode layer of the device, and the thickness of the evaporated layer is set to

Comparative example 1

Comparative element 1 was prepared by following the same procedure as in example 8, except that the compound represented by CEM was used instead of the metal complex in example 8.

The structural formulas of the aforementioned SC1, DNTPD, NPB, HT01, LiQ, CEM and ET010 are shown as follows:

the organic electroluminescent element was produced by using the metal complex of the present invention as a doping material for the organic light-emitting layer in the same procedure as described above, and the structure and performance data thereof are summarized in table 1:

TABLE 1

And (4) conclusion: from the analysis of performance test results, the metal complex of the invention has lower driving voltage relative to a comparative element, the performance of the metal complex is far beyond the performance of the prior known CEM, and the service life of the element is very ideal.

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that other variations or modifications may be made on the basis of the above description, and all embodiments may not be exhaustive, and all obvious variations or modifications may be included within the scope of the present invention.

Claims

1. A metal-carbene complex comprising an azaborine carbene ligand having the formula (I):

wherein M is Ir or Pt;

n is an integer of 1,2 or 3;

k is an uncharged monodentate or bidentate ligand;

l is a mono-or dianionic ligand, preferably a monoanionic ligand, which is a monodentate or bidentate ligand;

x is 0, 1 or 2, and when x is 2, the K ligands are the same or different;

y is 0, 1 or 2, and when y is 2, the L ligands are the same or different.

2. The metal-carbene complex according to claim 1, wherein M is Ir;

n is an integer of 1,2 or 3;

l is a monoanionic bidentate ligand;

x is 0;

y is 0, 1 or 2.

3. The metal-carbene complex according to claim 1 or 2, wherein L is a ligand represented by formula (II):

and R is⁸Cannot be hydrogen or deuterium;

a — represents a bond to the metal M.

4. An organic electronic component comprising at least one metal-carbene complex according to any of claims 1 to 3.

5. The organic electronic component of claim 4, which is an organic light emitting diode, an organic photovoltaic cell, an organic field effect transistor, or a light emitting electrochemical cell.

6. A light-emitting layer comprising at least one metal-carbene complex according to any of claims 1 to 3.

7. An organic light-emitting diode comprising the light-emitting layer according to claim 6.

8. An organic light-emitting diode comprising at least one metal-carbene complex according to any of claims 1 to 3 and at least one compound of the formula (III):

wherein T is NR¹⁷S, O or PR¹⁷；

R¹⁵、R¹⁶、R¹⁷、R¹⁸、R¹⁹Each independently selected from hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl, or R¹⁸、R¹⁹Together with the nitrogen atom, form a cyclic group having 3 to 10 ring atoms, which may be unsubstituted or substituted by one or more substituents selected from the group consisting of alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl and a group having donor action, and/or may be fused with one or more other cyclic groups having 3 to 10 ring atoms, wherein the fused group may be unsubstituted orSubstituted with one or more substituents selected from alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl and a group having donor or acceptor action;

a is an integer of 0-4;

b is an integer of 0 to 3;

9. An organic light-emitting diode according to claim 7 or 8, comprising an emissive layer comprising at least one metal-carbene complex according to any of claims 1 to 3, at least one matrix material of the formula (III) as defined in claim 8, and at least one further, preferably hole-transporting matrix material.

10. Use of a metal-carbene complex according to any of claims 1 to 3 in an organic light emitting diode.