Organic electroluminescent compound and application thereof

Abstract

The invention relates to an organic electrofluorescent compound as shown in a formula I and application thereof. The compound provided by the invention can be used as an organic electroluminescent material to emit dark blue light, is a pure organic fluorescent small molecule capable of emitting pure blue fluorescence, and can give consideration to high photoluminescence efficiency of a solid film and high exciton utilization rate in electroluminescence. The organic light-emitting device manufactured by doping the compound in a light-emitting layer can realize blue light emission with high color purity and high efficiency, and has important application prospects in the fields of ultra-high-definition display and illumination. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of organic electroluminescence, and relates to a class of organic electroluminescent compounds and their application in electroluminescent devices. Background Art

[0002] As a new display technology, organic light-emitting diodes (OLEDs) have important application prospects in display devices and lighting fields such as smartphones, tablets, and wearable electronic devices. At present, countries around the world are also accelerating the layout and upgrading of the OLED industry. In OLED technology, the choice of luminescent materials is crucial because it directly affects the electroluminescent performance of the device. Compared with green and red light materials that have reached commercial use, devices based on blue and deep blue light materials are still not satisfied with commercial applications in terms of device efficiency, stability, and color purity. Therefore, the development of blue and deep blue light emitting materials that can be used commercially has always been an important research area of concern to academia and the OLED industry.

[0003] In blue OLED devices, device efficiency and color purity are two key evaluation metrics. In 2012, the International Telecommunication Union (ITU) released BT 2020, a high-definition digital video standard. Compared to the previous BT709, BT 2020 specifies a wider color gamut and stricter requirements for the CIE coordinates of the three primary colors. The standard deep blue CIE coordinates are (0.131, 0.046).

[0004] Therefore, the development of blue light electroluminescent materials has very important practical significance. Summary of the Invention

[0005] After extensive research, the inventors of this invention have designed and synthesized a class of compounds with a planar, rigid molecular skeleton and excited-state properties exhibiting multiple resonance-thermally activated delayed fluorescence (MR-TADF). These compounds can be used as organic electroluminescent materials to emit deep blue light. They are small, pure organic fluorescent molecules capable of emitting pure blue fluorescence, balancing the high photoluminescence efficiency of solid-state thin films with high exciton utilization in electroluminescence. Organic electroluminescent devices fabricated by doping these compounds in a light-emitting layer can achieve high-color-purity, high-efficiency blue light emission, and have significant application prospects in ultra-high-definition display and lighting.

[0006] In one aspect, the present invention provides a compound of formula I:

[0007]

[0008] in,

[0009] X is selected from O, S, and Se;

[0010] Y is selected from CR1R2; wherein,

[0011] R1 and R2 are the same and are selected from substituted or unsubstituted C6-C12 aryl, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C5-C10 cycloalkyl; or

[0012] R1 and R2 together with the connected C form

[0013] R 41 to R 44 and R 51 to R 53 Each is independently selected from H, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C6-C12 aryl, substituted or unsubstituted C5-C10 cycloalkyl;

[0014] R 31 to R 33 Each is independently selected from H, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C6-C12 aryl, substituted or unsubstituted C5-C10 cycloalkyl;

[0015] or

[0016] R 41 、R 32 、R 33 Together

[0017] R 11 to R 14 Each is independently selected from substituted or unsubstituted C6-C12 aryl, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C5-C10 cycloalkyl;

[0018] or R 11 to R 14 The two adjacent groups in the group together with the connected C form a substituted or unsubstituted C6-C12 aromatic ring;

[0019] R 21 to R 25 Each is independently selected from H, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C6-C12 aryl, and substituted or unsubstituted C5-C10 cycloalkyl.

[0020] The substituted alkyl groups may be groups in which one or more hydrogen atoms are replaced by groups such as deuterium, halogen, cyano, nitro (-NO2), amino (-NH2), hydroxyl (-OH), C6-C12 aryl, 5-12 membered heteroaryl, C1-C6 alkoxy, C5-C8 cycloalkyl, etc.

[0021] The substituted aryl and cycloalkyl groups may be groups in which one or more hydrogen atoms are replaced by groups such as deuterium, halogen, cyano, nitro, amino, hydroxyl, C6-C12 aryl, 5-12 membered heteroaryl, C1-C6 alkyl, C1-C6 alkoxy, C5-C8 cycloalkyl, etc.

[0022] In some embodiments, in the compound of formula I, Y is selected from CR1R2, wherein

[0023] R1 and R2 are the same and are selected from C6-C10 aryl, C1-C4 alkyl, C5-C7 cycloalkyl, in particular phenyl, methyl, cyclohexyl;

[0024] Or R1 and R2 together with the connected C form

[0025] In some embodiments, in the compound of formula I, R 11 to R 14 Each independently selected from H, C1-C4 alkyl; in particular selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl; more particularly, R 11 、R 12 and R 14 H, R 13 Selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl;

[0026] or R 11 to R 14 The two adjacent groups in the group together with the connected C form a C6-C10 aromatic ring, in particular a benzene ring; more particularly, R 11 and R 14 H, R 12 and R 13 Together with the connected C, it forms a benzene ring.

[0027] In some embodiments, in the compound of formula I, R 21 to R 25 Each independently selected from H, C1-C4 alkyl, C6-C12 aryl, in particular selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, biphenyl; more particularly, R 21 and R 25 are the same, selected from H, C1-C4 alkyl, especially H, methyl; R 22 and R 24 are the same, selected from H, C1-C4 alkyl, especially H, methyl; R 23 Selected from H, methyl, phenyl, biphenyl.

[0028] In some embodiments, in the compound of formula I,

[0029] R 31 to R 33 Each independently selected from H, C1-C4 alkyl, unsubstituted or substituted C6-C12 aryl, C5-C7 cycloalkyl; in particular selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclohexyl, unsubstituted or substituted phenyl; the substituted substituents are selected from C1-C4 alkyl, C1-C4 alkoxy, in particular selected from methyl, ethyl; more particularly, R 31 and R 33 Selected from H, methyl, R 32 Selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclohexyl, 2,4,6-trimethylphenyl;

[0030] R 41 to R 44 and R 51 to R 53 Each is independently selected from H, C1-C4 alkyl, C6-C12 aryl, C5-C7 cycloalkyl; in particular, selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclohexyl, phenyl; more particularly, R 41 、R 42 、R 44 、R 51 、R 53 H, R 43 and R 52 Same, selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, cyclohexyl;

[0031] or

[0032] R 41 、R 32 、R 33 Together

[0033] X, R 11 to R 14 、R 21 to R 25 The definition of is as above.

[0034] In some embodiments, the compound of formula I is selected from the compound of formula II:

[0035]

[0036] Among them, X, Y, R 11 to R 14 、R 21 to R 25 、R 31 、R 42 to R44 and R 51 to R 53 The definition of is as above.

[0037] In this article, the following definitions are made:

[0038] Indicates where the group is attached to the parent core.

[0039] "Alkyl" can include straight or branched chain alkyl groups. Unless otherwise specified, an alkyl group can have 1 to 10 carbon atoms, for example, 1 to 6 carbon atoms, 1 to 4 carbon atoms, 1 to 3 carbon atoms, or 1 to 2 carbon atoms. Numerical ranges such as "1-10" refer to each integer in the given range; for example, "1 to 10 carbon atoms" refers to an alkyl group that can contain 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms. In addition, an alkyl group can be substituted or unsubstituted. An unsubstituted alkyl group can be a "saturated alkyl group" without any double or triple bonds. Specific examples of the alkyl group may include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, 1-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tertiary octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 2-methylpentyl, 4-methylhexyl, 5-methylhexyl, and the like, but are not limited thereto. C1-C10 alkyl refers to a straight or branched chain alkyl group containing 1 to 10 carbon atoms, and the same applies to C1-C6 alkyl and C1-C4 alkyl.

[0040] "Alkoxy" means a RO- group where R is alkyl as defined above.

[0041] "Aryl" refers to an optional functional group or substituent derived from an aromatic carbocyclic ring. The aryl group can be a monocyclic aryl group (e.g., phenyl) or a polycyclic aryl group. In other words, the aryl group can be a monocyclic aryl group, a fused ring aryl group, two or more monocyclic aryl groups connected by conjugation of carbon-carbon bonds, a monocyclic aryl group and a fused ring aryl group connected by conjugation of carbon-carbon bonds, or two or more fused ring aryl groups connected by conjugation of carbon-carbon bonds. That is, unless otherwise specified, two or more aromatic groups connected by conjugation of carbon-carbon bonds can also be regarded as aryl groups of the present disclosure. Among them, fused ring aryl groups can, for example, include bicyclic fused aryl groups (e.g., naphthyl), tricyclic fused aryl groups (e.g., phenanthrenyl, fluorenyl, anthracenyl), etc. The aryl group does not contain heteroatoms such as B, N, O, S, P, Se, and Si. For example, in the present disclosure, biphenyl, terphenyl, etc. are aryl groups. Unless otherwise specified, "aryl" can contain 6-30, 6-25, 6-18, or 6-13 carbon atoms. For example, the number of carbon atoms in an aryl group can be 6, 10, 12, 13, 14, 15, 18, 20, 24, 25, or 30. Of course, the number of carbon atoms can also be other numbers, which are not listed here. Specific examples of aryl groups include phenyl, biphenyl, triphenyl, naphthyl, anthracenyl, The term "C6-C12 aryl" refers to a monocyclic or polycyclic aromatic group having 6 to 12 carbon atoms. The meaning of C6-C10 aryl is similar.

[0042] "Heteroaryl" refers to a monovalent aromatic ring containing at least one, for example 1, 2, 3, 4 or 5, heteroatom in the ring, wherein the heteroatom can be at least one selected from B, O, N, P, Si, Se and S. The heteroaryl group can be a monocyclic heteroaryl group or a polycyclic heteroaryl group. In other words, the heteroaryl group can be a single aromatic ring system or a plurality of aromatic ring systems connected by conjugation, and any aromatic ring system can be an aromatic monocyclic ring or an aromatic fused ring. For example, the heteroaryl group can include thienyl, furyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, oxadiazolyl, triazolyl, pyridyl, bipyridyl, pyrimidyl, triazinyl, acridinyl, pyridazinyl, pyrazinyl, quinolyl, quinazolinyl, quinoxalinyl, phenoxazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolyl, indolyl, carbazolyl, benzoxazolyl, benzimidazolyl, benzo[pi]midazolyl ... Thiazolyl, benzotriazolyl, benzocarbazolyl, benzothiophenyl, dibenzothiophenyl, thienothiphenyl, benzofuranyl, phenanthrolinyl, isoxazolyl, thiadiazolyl, benzothiazolyl, phenothiazinyl, silafluorenyl, dibenzofuranyl, and N-arylcarbazolyl (such as N-phenylcarbazolyl), N-heteroarylcarbazolyl (such as N-pyridylcarbazolyl), N-alkylcarbazolyl (such as N-methylcarbazolyl), etc., without limitation. Among them, thienyl, furanyl, phenanthrolinyl, etc. are heteroaryl groups of the single aromatic ring system type, and N-arylcarbazolyl and N-heteroarylcarbazolyl are heteroaryl groups of the multi-ring system type connected by conjugation. Unless otherwise specified, the "heteroaryl" of the present application may contain 5-30, 5-23 or 5-19 ring atoms. For example, the number of ring atoms can be 5, 6, 7, 10, 11, 12, 13, 18, 19, 20, 21, 22, 23, 25 or 30. Of course, the number of ring atoms can also be other numbers, which are not listed here one by one. Specific examples of heteroaryl groups include pyridyl, pyrrolyl, pyrimidinyl, pyridazinyl, etc., but are not limited to these. 5-12 membered heteroaryl refers to a monocyclic or polycyclic heteroaryl group having 5 to 12 ring atoms. In particular, heteroaryl is a heteroaryl group containing carbon atoms and 1 to 3 N as heteroatoms.

[0043] The halogen group may include fluorine, chlorine, bromine, iodine, and the like.

[0044] Cyano refers to -CN.

[0045] In some embodiments, the compound of formula I is selected from the following compounds:

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053] Based on the structures of the compounds disclosed in the present invention, those skilled in the art can design appropriate synthetic routes to synthesize the compounds of the present invention using reaction principles known in the art, or synthesize the compounds of the present invention using the synthetic routes disclosed in the Examples. Therefore, the present invention does not specifically limit the synthetic methods of the compounds of the present invention.

[0054] In some embodiments, the compounds of the present invention can be obtained by referring to one of the following methods:

[0055] Method 1

[0056]

[0057] (S11) Compound a1 and a2 are reacted via Buchwald-Hartwig cross coupling to obtain compound a3;

[0058] (S12) Compound a3 and a4 are reacted via Buchwald-Hartwig cross coupling to obtain compound a5;

[0059] (S13) Compound a5 is reacted with BBr3 via one-shot borylation to obtain compound II;

[0060] Method 2

[0061]

[0062] (S21) Compound b1 and a2 are reacted via Buchwald-Hartwig cross coupling to obtain compound b2;

[0063] (S22) Compound b2 and a4 are reacted via Buchwald-Hartwig cross coupling to obtain compound b3;

[0064] (S23) Compound b3 reacts with BBr3 via one-shot borylation to obtain compound I;

[0065] Among them, X, Y, R 11 to R 14 、R 21 to R 25 、R 31 to R 33 、R 41 to R 44 and R 51 to R 53 The definition of is as above.

[0066] Steps S11 and S21 can be carried out in a solvent in the presence of a catalyst and a base. The catalyst is, for example, tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) and 2-(dicyclohexylphosphine)-3,6-dimethoxy-2'-4'-6'-tri-1-propyl-11'-biphenyl (Brettphos), the base is, for example, sodium tert-butoxide (t-BuONa), and the solvent is, for example, toluene, but the present invention is not limited thereto. Those skilled in the art can select appropriate reaction conditions based on the reaction principle.

[0067] The above steps S12 and S22 can be carried out in a solvent in the presence of a catalyst and a base. The catalyst is, for example, tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) and 2-(dicyclohexylphosphine)-3,6-dimethoxy-2'-4'-6'-tri-1-propyl-11'-biphenyl (Brettphos), the base is, for example, sodium tert-butoxide (t-BuONa), and the solvent is, for example, toluene, but the present invention is not limited thereto. Those skilled in the art can select appropriate reaction conditions based on the reaction principle.

[0068] The above steps S13 and S23 can be performed in a solvent, such as o-dichlorobenzene (o-DCB), but the present invention is not limited thereto. Those skilled in the art can select appropriate reaction conditions based on the reaction principle.

[0069] Compounds a1 and b1 may be commercially available compounds, or may be synthesized by any suitable method, which is not limited in the present invention.

[0070] In some embodiments, compounds a1 and b1 can be obtained by reacting compound a0 or b0 with compound c1 or c2 via Buchwald-Hartwig Cross Coupling, as shown in the following reaction formula:

[0071]

[0072] However, the present invention is not limited thereto.

[0073] The reaction of compound a0 or b0 with compound c1 or c2 can be carried out in a solvent in the presence of a catalyst and a base. The catalyst is, for example, tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) and tri-tert-butylphosphine tetrafluoroborate, the base is, for example, sodium tert-butoxide (t-BuONa), and the solvent is, for example, toluene. However, the present invention is not limited thereto, and those skilled in the art can select appropriate reaction conditions based on the reaction principle.

[0074] The compounds of the present invention are pure organic fluorescent small molecules capable of emitting pure blue fluorescence. They have a rigid molecular skeleton and multiple resonance-thermally activated delayed fluorescence (MR-TADF) excited state properties. Organic electroluminescent devices made by doping such materials in the light-emitting layer can achieve high-color purity and high-efficiency blue light emission, and have important application prospects in the fields of ultra-high-definition display and lighting.

[0075] Another aspect of the present invention provides use of the compound of the present invention in preparing an organic electroluminescent material, an organic electroluminescent device or a display device.

[0076] Another aspect of the present invention provides an organic electroluminescent material, an organic electroluminescent device or a display apparatus comprising the compound of the present invention.

[0077] The organic electroluminescent material can be, for example, a light-emitting layer material, which includes the compound of the present invention described above. In particular, the light-emitting layer material includes the compound of the present invention described above as a light-emitting guest material (as a guest, the main function is to accept energy and emit light by radiative transition). The light-emitting layer material can also include a light-emitting host material (which, as the main component of the light-emitting layer, has the function of transporting carriers and providing an exciton recombination area. In addition, it also assumes the role of transferring exciton energy to the guest or sensitizing host), a sensitizing material (which, as a sensitizing host, receives the energy of the host triplet exciton and forms a singlet exciton by anti-intersystem crossing, and then transfers the energy to the guest molecule. Usually, when the guest is difficult to utilize triplet excitons, a sensitizing host is introduced to improve the exciton utilization rate) or other doping materials. For example, the light-emitting host material can be PhCz, and the sensitizing material can be 4T, but is not limited thereto. In some embodiments, in the light-emitting layer material, the content of the light-emitting guest can be 1-10%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc., for example, 4-8%, based on the total weight of the material; the content of the sensitizing material can be 5-40%, for example, 10%, 12%, 15%, 18%, 20%, 25%, 30%, 355, 40%, etc., for example, 15-30%; the content of the light-emitting host material can be 94-50%, for example, 93%, 90%, 89%, 85%, 82%, 80%, 75%, 70%, 65%, 60%, 55%, etc., for example, 81-66%, but is not limited thereto.

[0078] In an embodiment, the organic electroluminescent device includes a light-emitting layer, and the light-emitting layer contains the compound of the present invention.

[0079] It should be noted that in an organic electroluminescent device, the light-emitting layer may be provided as a single layer, or as two or more layers. When the light-emitting layer is provided as two or more layers, the plurality of light-emitting layers may be stacked, and at least one light-emitting layer comprises the compound of the present invention.

[0080] In an embodiment, the compound of the present invention is used as a luminescent guest material in the light-emitting layer. In addition to the compound of the present invention, the light-emitting layer may further include a host material, a sensitizing material, or other dopant material. For example, the host material may be PhCz, and the sensitizing material may be 4T, but are not limited thereto.

[0081] In addition to the light-emitting layer, the organic electroluminescent device may further include one or more layers of, but not limited to, a cathode, an anode, an electron blocking layer, an electron transport layer, an electron injection layer, a hole injection layer, a hole transport layer, a hole blocking layer, a covering layer, and an encapsulation layer. The organic electroluminescent device may have a structure of a conventional organic electroluminescent device without particular limitation. For example, the organic electroluminescent device may have a structure of, but not limited to, an anode / hole injection layer / hole transport layer / electron blocking layer / light-emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode.

[0082] The material of the anode layer can be selected from metals such as copper, gold, silver, iron, chromium, nickel, manganese, palladium, platinum, and alloys thereof. The anode material can also be selected from metal oxides such as indium oxide, zinc oxide, indium tin oxide (ITO), and indium zinc oxide (IZO). The anode material can also be selected from conductive polymers such as polyaniline, polypyrrole, and poly(3-methylthiophene). Furthermore, the anode material can be selected from materials other than the listed anode materials that facilitate hole injection, and combinations thereof, including known materials suitable for use as anodes.

[0083] The material of the cathode layer can be selected from metals such as aluminum, magnesium, silver, indium, tin, titanium, and alloys thereof. The cathode material can also be selected from multilayer metal materials such as LiF / Al, LiO2 / Al, BaF2 / Al, and the like. In addition to the cathode materials listed above, the cathode material can also be a material that facilitates electron injection and a combination thereof, including known materials suitable for cathodes.

[0084] Organic electroluminescent devices can be fabricated using methods known in the art and will not be described in detail here. An organic electroluminescent device can be fabricated by forming an anode on a transparent or opaque smooth substrate, forming an organic thin layer on the anode, and forming a cathode on the organic thin layer. The organic thin layer can be formed using known film-forming methods such as evaporation, sputtering, spin coating, dipping, and ion plating.

[0085] The specific structures, material compositions, and preparation methods of the cathode, anode, electron blocking layer, electron transport layer, electron injection layer, hole injection layer, hole transport layer, hole blocking layer, capping layer, and encapsulation layer of the embodiments of the present invention may adopt any suitable structures, material compositions, and preparation methods without particular limitation. The present invention does not involve improvements to these components, and therefore these components are not described in detail to avoid obscuring the main technical ideas of the present invention.

[0086] A display apparatus includes the organic electroluminescent device according to the present invention.

[0087] The display device may be any display screen, such as a mobile phone display, a computer display, a television display, a smartwatch display, a smart car display, a VR or AR helmet display, or displays of various smart devices. Alternatively, it may be any product or component with a display function, such as a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame, a navigation system, a smartwatch, a fitness band, or a personal digital assistant. Other essential components of the display device are well understood by those skilled in the art and are not detailed here, nor should they be construed as limitations of the present invention.

[0088] Beneficial effects

[0089] Compared with conventional materials, the compound of the present invention has a high glass transition temperature (Tg>300° C.), improves the stability of the luminescent molecules, increases steric hindrance, and inhibits aggregation.

[0090] In addition, to suppress aggregation quenching, conventional electroluminescent device guests using boron nitrogen molecules as the light-emitting layer material are doped at low concentrations, for example, with a doping concentration of less than 4 wt% (based on the total weight of the light-emitting layer). For example, Xingyu Huang et al. (National Science Review, Volume 11, Issue 6, June 2024, https: / / doi.org / 10.1093 / nsr / nwae115) used a 2% doping concentration. However, the compounds of the present invention have good effects when the doping concentration is between 4-8%, eliminating the need to control the doping concentration below 4% or to precisely control the doping concentration, thereby reducing the precision requirements of the doping process.

[0091] The deep blue electroluminescent device obtained by using the compound of the present invention as a luminescent guest has the advantages of low turn-on voltage, high brightness, high color purity, low efficiency roll-off, etc., and the electroluminescent peak is around 460nm.

[0092] The present invention has been described in detail above, but the above embodiments are merely illustrative in nature and are not intended to limit the present invention. In addition, the present invention is not limited by any theory described in the above prior art or invention summary or the following examples.

[0093] In the present invention, the description method used "independently" should be understood in a broad sense, which can mean that in different groups, the specific options expressed by the same symbols do not affect each other, or that in the same group, the specific options expressed by the same symbols do not affect each other.

[0094] In the present invention, the word "comprise" or its variations, such as "include", "contain", "have" will be understood to include the stated elements, integers or steps, or a combination of elements, integers or steps, but does not exclude the addition of other elements, integers or steps, or a combination of elements, integers or steps.

[0095] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those of ordinary skill in the art to which the present invention belongs. Although similar or equivalent methods and materials described herein may be used in the practice or testing of the present invention, suitable methods and materials will be described below. In the event of conflict, this specification (including definitions) shall prevail. In addition, the materials, methods, and embodiments are merely illustrative and are not intended to be restrictive.

[0096] “At least one of A, B and C” has the same meaning as “at least one of A, B or C” and both include the following combinations of A, B and C: A only, B only, C only, the combination of A and B, the combination of A and C, the combination of B and C, and the combination of A, B and C.

[0097] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0098] In the present invention, unless otherwise specified, "plurality" means two or more.

[0099] Unless otherwise expressly stated, numerical ranges throughout this application include any subranges therein and any numerical values in increments of the smallest subunit of a given value therein. Unless otherwise expressly stated, numerical values throughout this application represent approximate measures or limits of the range of embodiments that include minor deviations from the given value and have approximately the stated value as well as the stated exact value. Except for the working examples provided at the end of the detailed description, all numerical values for parameters (e.g., quantities or conditions) in this application (including the appended claims) should be understood in all cases as being modified by the term "approximately", regardless of whether "approximately" actually appears before the value. "Approximately" means that the stated value allows for slight imprecision (some approach to exactness in the value; approximately or reasonably close to the value; approximately). If the imprecision provided by "approximately" is not understood in this ordinary sense in the art, "approximately" as used herein at least represents the variation that can be produced by ordinary methods of measuring and using these parameters. For example, "approximately" can include variations of less than or equal to 10%, less than or equal to 5%, less than or equal to 4%, less than or equal to 3%, less than or equal to 2%, less than or equal to 1% or less than or equal to 0.5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0100] Figure 1 Shows the DSC curves of Example Compound 4, Compound 8, and Compound 12 respectively;

[0101] Figure 2-7 The electroluminescence spectra, the relationship curve between external quantum efficiency and brightness, the current density-voltage relationship curve, the brightness-voltage relationship curve, the current efficiency-brightness relationship curve, and the power efficiency-brightness relationship curve of the organic electroluminescent devices prepared with Example Compound 4, Compound 8, and Compound 12 as the light-emitting layer guest materials are respectively shown. DETAILED DESCRIPTION

[0102] The present invention will be further described below with reference to the examples. It should be noted that the following examples are provided for illustrative purposes only and do not constitute a limitation on the scope of protection claimed in the present invention.

[0103] Unless otherwise specified, the raw materials, reagents, methods, etc. used in the examples are conventional raw materials, reagents, and methods in the art.

[0104] All raw materials were purchased from commercial sources, including Zhengzhou Alpha Chemical Co., Ltd., Shanghai Bid Pharmaceutical Co., Ltd., Shanghai MacLean Biochemical Technology Co., Ltd., and Anhui Zesheng Technology Co., Ltd. Solvents were purchased from Tianjin Yongda Chemical Reagent Co., Ltd.

[0105] Example 1: Synthesis of Compound 4

[0106]

[0107] To a 100ml round-bottom flask, starting material 1 (1.7g, 7.5mmol), starting material 2 (1.6g, 3.3mmol), tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) (92mg, 0.1mmol), tri-tert-butylphosphine tetrafluoroborate (tBu3PHBF4) (0.17g, 0.6mmol), sodium tert-butoxide (t-BuONa) (1.3g, 13mmol), and 25ml of toluene were added in sequence. The reaction system was refluxed at 110°C under nitrogen for 32h. After the reaction was completed, the mixture was cooled to room temperature, added with excess deionized water, and extracted three times with dichloromethane. The resulting organic layer was dried over anhydrous magnesium sulfate, concentrated, and separated by column chromatography to obtain 1.3g of compound 1 as a white solid (yield: 54%).

[0108]

[0109] To a 100 ml round-bottom flask, compound 1 (1.1 g, 2.3 mmol), 2,4,6-trimethylaniline (0.8 g, 6.0 mmol), tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) (85 mg, 0.092 mmol), 2-(dicyclohexylphosphino)-3,6-dimethoxy-2'-4'-6'-tri-1-propyl-11'-biphenyl (Brettphos) (0.15 g, 0.28 mmol), sodium tert-butoxide (t-BuONa) (0.83 g, 8.6 mmol), and 18 ml of toluene were added sequentially. The reaction system was refluxed at 110°C under nitrogen for 32 h. After the reaction was completed, the mixture was cooled to room temperature, excess deionized water was added, and the mixture was extracted three times with dichloromethane. The obtained organic layer was dried over anhydrous magnesium sulfate, concentrated, and separated by column chromatography to obtain 1.3 g of compound 2 as a white solid (yield: 87%).

[0110]

[0111] To a 100ml round-bottom flask, compound 2 (1.3g, 2.0mmol), 3-bromobenzofuran (1.0g, 5.0mmol), tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) (73mg, 0.080mmol), tri-tert-butylphosphine tetrafluoroborate (tBu3PHBF4) (0.14g, 0.48mmol), sodium tert-butoxide (t-BuONa) (0.72g, 7.5mmol), and 15ml of toluene were added sequentially. The reaction system was refluxed at 110°C under nitrogen for 32h. After the reaction was completed, the mixture was cooled to room temperature, added with excess deionized water, and extracted three times with dichloromethane. The resulting organic layer was dried over anhydrous magnesium sulfate, concentrated, separated by column chromatography, and recrystallized from methanol to obtain 0.62g of compound 3 as a white solid (yield: 34%).

[0112]

[0113] To a 100ml autoclave, compound 3 (0.52g, 0.57mmol), boron tribromide (BBr3) (0.70g, 2.8mmol), and 10ml of o-dichlorobenzene (o-DCB) were added sequentially. The reaction system was refluxed at 190°C under nitrogen for 20h. After completion of the reaction, the mixture was cooled to room temperature and evaporated under reduced pressure. Excess deionized water was added, and the mixture was extracted three times with dichloromethane. The resulting organic layer was dried over anhydrous magnesium sulfate, concentrated, separated by column chromatography, and recrystallized from methanol to obtain 70mg of compound 4 as a yellow-green solid (yield: 14%).

[0114] Example 2: Synthesis of Compound 8

[0115]

[0116] To a 250ml round-bottom flask, 3-bromo-5-chlorotoluene (9.0g, 45mmol), starting material 2 (10g, 30mmol), tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) (0.55g, 0.60mmol), tri-tert-butylphosphine tetrafluoroborate (tBu3PHBF4) (0.72g, 2.4mmol), sodium tert-butoxide (t-BuONa) (7.8g, 78mmol), and 40ml of toluene were added in sequence. The reaction system was refluxed at 110°C under nitrogen for 32h. After the reaction was completed, the mixture was cooled to room temperature, added with excess deionized water, and extracted three times with dichloromethane. The resulting organic layer was dried over anhydrous magnesium sulfate, concentrated, and separated by column chromatography to obtain 5.9g of compound 5 as a white solid (yield: 44%).

[0117]

[0118] To a 250 ml round-bottom flask, compound 5 (5.9 g, 13 mmol), 2,4,6-trimethylaniline (2.6 g, 20 mmol), tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) (0.24 g, 0.092 mmol), 2-(dicyclohexylphosphine)-3,6-dimethoxy-2'-4'-6'-tri-1-propyl-11'-biphenyl (Brettphos) (0.42 g, 0.78 mmol), sodium tert-butoxide (t-BuONa) (3.1 g, 32 mmol), and 70 ml of toluene were added in sequence. The reaction system was refluxed at 110°C under nitrogen for 32 h. After the reaction, the mixture was cooled to room temperature, excess deionized water was added, and the mixture was extracted three times with dichloromethane. The obtained organic layer was dried over anhydrous magnesium sulfate, concentrated, and separated by column chromatography to obtain 6.0 g of compound 6 as a white solid (yield: 83%).

[0119]

[0120] To a 250ml round-bottom flask were added compound 6 (5.5g, 10mmol), 3-bromobenzofuran (3.0g, 15mmol), tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) (0.18g, 0.20mmol), tri-tert-butylphosphine tetrafluoroborate (tBu3PHBF4) (0.23g, 0.80mmol), sodium tert-butoxide (t-BuONa) (2.4g, 25mmol), and 50ml of toluene. The reaction system was refluxed at 110°C under nitrogen for 32h. After the reaction was completed, the mixture was cooled to room temperature, added with excess deionized water, and extracted three times with dichloromethane. The resulting organic layer was dried over anhydrous magnesium sulfate, concentrated, separated by column chromatography, and recrystallized from methanol to obtain 2.0g of compound 7 as a white solid (yield: 30%).

[0121] Synthesis of compound 8:

[0122]

[0123] To a 100ml autoclave, compound 7 (2.0g, 3.0mmol), boron tribromide (BBr3) (5.0g, 20mmol), and 10ml of o-dichlorobenzene (o-DCB) were added sequentially. The reaction system was refluxed at 190°C under nitrogen for 20h. After completion of the reaction, the mixture was cooled to room temperature and evaporated under reduced pressure. Excess deionized water was added, and the mixture was extracted three times with dichloromethane. The resulting organic layer was dried over anhydrous magnesium sulfate, concentrated, separated by column chromatography, and recrystallized from methanol to obtain 0.31g of compound 8 as a yellow-green solid (yield: 15%).

[0124] Example 3: Synthesis of Compound 12

[0125]

[0126] The synthesis of compound 5 was similar to that in Example 2, except that raw material 3 was used instead of raw material 2, to obtain 3.0 g of compound 9 as a light yellow solid (yield: 75%).

[0127]

[0128] The synthesis of compound 6 was similar to that in Example 2, except that compound 9 was used instead of compound 5, to obtain 3.0 g of compound 10 as a white solid (yield: 78%).

[0129]

[0130] The synthesis of compound 7 was similar to that in Example 2, except that compound 10 was used instead of compound 6, to obtain 1.7 g of compound 11 as a white solid (yield: 42%).

[0131]

[0132] The synthesis of compound 8 was similar to that in Example 2, except that compound 11 was used instead of compound 7, to obtain 0.52 g of compound 12 as a white solid (yield: 39%).

[0133] Table 1 lists the compounds 4, 8 and 12. 1 H NMR characterization data.

[0134] Table 1

[0135]

[0136] DSC measurements

[0137] Differential scanning calorimetry (DSC) was performed on compounds 4, 8, and 12 using a differential scanning calorimeter (Q20) from TA, USA. About 3 mg of the compound was accurately weighed and placed in a crucible. The crucible containing the compound and a blank crucible were placed in the cavity of the differential scanning calorimeter. The initial temperature was set to 20°C, and the temperature was raised to 320°C at a rate of 10°C / min, and then cooled to 20°C at a rate of 10°C / min, and the cycle was repeated three times. The resulting DSC curve is shown in Figure 2. Figure 1 As shown, the test temperature range is 20-320°C, two cycles are scanned, and the second cycle is taken as the reported data.

[0138] Figure 1The DSC curve is almost a horizontal line, indicating that there is no glass transition within the test temperature range, and it can be considered that its glass transition temperature Tg is greater than 300° C. This shows that the compound of the present invention has a high glass transition temperature, which improves the stability of the luminescent molecule.

[0139] Application example: Preparation and characterization of electroluminescent devices

[0140] ITO glass plate preparation:

[0141] First, soak the ITO glass plate in a 1:1 volume ratio of deionized water and ethanol for 4 hours. Then, wipe it clean with a dust-free paper and repeatedly ultrasonically clean it with a clean solvent of isopropyl alcohol, acetone, toluene, tetrahydrofuran, chloroform, and isopropyl alcohol. Before transferring it to a glove box, purge any remaining organic solvent from the ITO glass plate with nitrogen. Then, irradiate it with a UV cleaner for 20 minutes before transferring it to a vacuum evaporation chamber for deposition.

[0142] Preparation of organic electroluminescent devices

[0143] Organic electroluminescent devices were prepared by evaporation using Compound 4, Compound 8, and Compound 12 of the Example as guest materials for the light-emitting layer according to the following structure from bottom to top:

[0144] ITO / HATCN(5nm) / TAPC(30nm) / TCTA(15nm) / mCP(10nm) / PhCz(81%):4T(15%):Compound 4(4%)(20nm) / TmPyPB(30nm) / LiF(1nm) / Al(100nm)

[0145] ITO / HATCN(5nm) / TAPC(30nm) / TCTA(15nm) / mCP(10nm) / PhCz(81%):4T(15%):Compound 8(4%)(20nm) / TmPyPB(30nm) / LiF(1nm) / Al(100nm)

[0146] ITO / HATCN(5nm) / TAPC(30nm) / TCTA(15nm) / mCP(10nm) / PhCz(62%):4T(30%):Compound 12(8%)(20nm) / TmPyPB(30nm) / LiF(1nm) / Al(100nm)

[0147] in,

[0148] HATCN is the hole injection layer, and the evaporation rate is 0.1As -1 ;

[0149] TAPC is the hole transport layer, and the evaporation rate is 1.0As-1 ;

[0150] TCTA is a hole blocking layer with an evaporation rate of 1.0 As -1 ;

[0151] mCP is a hole blocking layer, and the evaporation rate is 0.5As -1 , 30 minutes after the evaporation of this layer is completed, the light-emitting layer is evaporated;

[0152] PhCz:4T: Compound 4 or 8 or 12 is the light-emitting layer, wherein PhCz is the host material, 4T is the sensitizing material, and compound 4 or 8 or 12 is the guest material. The percentage in the brackets is the mass fraction based on the total mass of the light-emitting layer. The evaporation rate is 0.5As. -1 ;

[0153] TmPyPB is the electron transport layer, and the evaporation rate is 0.4As -1

[0154] LiF is the electron injection layer, and the evaporation rate is 0.1As -1 ;

[0155] Al is the cathode, and the evaporation rate is 3.0As -1 .

[0156] The material structures of HATCN, TAPC, TCTA, mCP, PhCz, 4T, and TmPyPB are as follows:

[0157]

[0158] A DC voltage was applied to the prepared organic electroluminescent device, and the luminescence performance was tested using a Spectrascan PR650 luminance meter. The current-voltage characteristics were measured using a computer-controlled Keithley 2400 digital source meter. As luminescence characteristics, the electroluminescence spectrum and current efficiency (cd A) under the change of the applied DC voltage were measured. -1 ), CIE color coordinates, external quantum efficiency (%), power efficiency (lm / W), maximum brightness (cd / m 2 ).

[0159] The electroluminescence spectrum, external quantum efficiency-brightness curve, current density-voltage curve, brightness-voltage curve, current efficiency-brightness curve, power efficiency-brightness curve of the organic electroluminescent device prepared with the example compound as the guest material of the light-emitting layer are shown in FIG. Figure 2-Figure 7 shown.

[0160] The electroluminescent properties of the organic electroluminescent devices are summarized in Table 2.

[0161] Table 2 Performance of blue organic electroluminescent devices of compounds

[0162]

[0163] The electroluminescent properties of organic electroluminescent devices prepared from the above compounds show that the compounds of the present invention, when used as luminescent guests, in combination with suitable sensitizing materials and luminescent hosts, can produce a series of deep-blue electroluminescent devices with an electroluminescence peak around 460 nm. These electroluminescent devices also exhibit advantages such as low turn-on voltage, high brightness, high color purity, and low efficiency roll-off. In particular, devices based on compound 12 exhibit a deep-blue electroluminescence spectrum of 464 nm, color coordinates of (0.143, 0.173), and an external quantum efficiency of 33.87%, representing advanced device performance for deep-blue light devices.

[0164] The above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced with equivalents, without departing from the spirit and substance of the claims of the present invention; and such modifications or replacements remain within the scope of the claims of the present invention.

Claims

1. Compound of formula I: in, X is selected from O, S, and Se; Y is selected from CR1R2; wherein, R1 and R2 are the same and are selected from substituted or unsubstituted C6-C12 aryl, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C5-C10 cycloalkyl; or R1 and R2 together with the connected C form R 41 to R 44 and R 51 to R 53 Each is independently selected from H, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C6-C12 aryl, substituted or unsubstituted C5-C10 cycloalkyl; R 31 to R 33 Each is independently selected from H, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C6-C12 aryl, substituted or unsubstituted C5-C10 cycloalkyl; or R 41 、R 32 、R 33 Together R 11 to R 14 Each is independently selected from substituted or unsubstituted C6-C12 aryl, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C5-C10 cycloalkyl; or R 11 to R 14 The two adjacent groups in the group together with the connected C form a substituted or unsubstituted C6-C12 aromatic ring; R 21 to R 25 Each is independently selected from H, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C6-C12 aryl, substituted or unsubstituted C5-C10 cycloalkyl, Wherein, the substituted alkyl groups are groups in which one or more hydrogen atoms are replaced by a group selected from deuterium, halogen, cyano, -NO2, -NH2, -OH, C6-C12 aryl, 5-12 membered heteroaryl, C1-C6 alkoxy, C5-C8 cycloalkyl, Substituted aryl and cycloalkyl groups are groups in which one or more hydrogen atoms are replaced by a group selected from deuterium, halogen, cyano, nitro, amino, hydroxyl, C6-C12 aryl, 5-12 membered heteroaryl, C1-C6 alkyl, C1-C6 alkoxy, and C5-C8 cycloalkyl.

2. The compound according to claim 1, wherein Y is selected from CR1R2, wherein R1 and R2 are the same and are selected from C6-C10 aryl, C1-C4 alkyl, C5-C7 cycloalkyl, in particular phenyl, methyl, cyclohexyl; Or R1 and R2 together with the connected C form R 11 to R 14 Each independently selected from H, C1-C4 alkyl; in particular selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl; more particularly, R 11 、R 12 and R 14 H, R 13 Selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl; or R 11 to R 14 The two adjacent groups in the group together with the connected C form a C6-C10 aromatic ring, in particular a benzene ring; more particularly, R 11 and R 14 H, R 12 and R 13 Together with the connected C, it forms a benzene ring; and / or R 21 to R 25 Each independently selected from H, C1-C4 alkyl, C6-C12 aryl, in particular selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, biphenyl; more particularly, R 21 and R 25 are the same, selected from H, C1-C4 alkyl, especially H, methyl; R 22 and R 24 are the same, selected from H, C1-C4 alkyl, especially H, methyl; R 23 Selected from H, methyl, phenyl, biphenyl.

3. The compound according to claim 1 or 2, wherein R 31 to R 33 Each independently selected from H, C1-C4 alkyl, unsubstituted or substituted C6-C12 aryl, C5-C7 cycloalkyl; in particular selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclohexyl, unsubstituted or substituted phenyl; the substituted substituents are selected from C1-C4 alkyl, C1-C4 alkoxy, in particular selected from methyl, ethyl; more particularly, R 31 and R 33 Selected from H, methyl, R 32 Selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclohexyl, 2,4,6-trimethylphenyl; R 41 to R 44 and R 51 to R 53 Each is independently selected from H, C1-C4 alkyl, C6-C12 aryl, C5-C7 cycloalkyl; in particular, selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclohexyl, phenyl; more particularly, R 41 、R 42 、R 44 、R 51 、R 53 H, R 43 and R 52 Same, selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, cyclohexyl; or R 41 、R 32 、R 33 Together X, R 11 to R 14 、R 21 to R 25 The definition of the corresponding claims.

4. The compound according to any one of claims 1 to 3, wherein The compound of formula I is selected from the compounds of formula II: Among them, X, Y, R 11 to R 14 、R 21 to R 25 、R 31 、R 42 to R 44 and R 51 to R 53 As described in the corresponding claims.

5. The compound according to claim 1, wherein The compound of formula I is selected from the following compounds:

6. Use of the compound according to any one of claims 1 to 5 in the preparation of an organic electroluminescent material, an organic electroluminescent device or a display device.

7. An organic electroluminescent material comprising the compound according to any one of claims 1 to 5, in particular, the organic electroluminescent material is a light-emitting layer material, comprising the compound according to any one of claims 1 to 4 as a light-emitting guest material.

8. An organic electroluminescent device comprising the compound according to any one of claims 1 to 5, particularly, the organic electroluminescent device comprises a light-emitting layer, the light-emitting layer contains the compound according to any one of claims 1 to 4, more particularly, the compound according to any one of claims 1 to 4 serves as a light-emitting guest material in the light-emitting layer. 9 . A display device comprising the organic electroluminescent device according to claim 8 .

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