CN114621272A - Boron-nitrogen compound, organic electroluminescent composition and organic electroluminescent device comprising same - Google Patents

Abstract

The present disclosure provides boron nitrogen compounds of formula I or II, compositions comprising the compounds, and their use in the field of organic electroluminescence. The present disclosure also provides a method of preparing a boron nitrogen compound of formula I or II. The organic electroluminescent device prepared by the compound or the composition provided by the invention can realize high-efficiency green light and red light electroluminescence with narrow spectrum emission.

Description

Boron-nitrogen compound, organic electroluminescent composition and organic electroluminescent device comprising same

Technical Field

The invention belongs to the technical field of organic electroluminescence, and particularly relates to a boron-nitrogen compound, a synthetic method thereof, an organic electroluminescent composition and an organic electroluminescent device containing the compound or the composition.

Background

The organic electroluminescent technology has great application prospect in the fields of full-color display and solid-state white light illumination, and has been widely researched and paid attention to in the scientific research community and the industrial community. Organic small molecule photoelectric materials are widely used as high-performance electroluminescent materials due to the advantages of definite structure, easy modification, simple purification and processing and the like. At present, conventional fluorescent dyes are usedWhile photoluminescence quantum yields tend to be very high, electroluminescent devices based on these fluorescent materials are limited by internal quantum efficiencies of 25%, and external quantum efficiencies of electroluminescent devices are generally lower than 5%, which is far from the efficiency of phosphorescent devices. At present, a delayed fluorescence mechanism is mainly adopted in a fluorescent electroluminescent device capable of breaking through the limitation of 25% of internal quantum efficiency, and the triplet excited state energy in the device can be effectively utilized by utilizing the mechanism. Delayed fluorescence mechanisms mainly include two types: (1) TTA (Triplet-Triplet Annihilation) mechanism; (2) TADF (Thermally Activated Delayed Fluorescence) mechanism. The TTA mechanism is a mechanism for improving the generation ratio of singlet excitons by utilizing the fusion of two triplet excitons, but the maximum internal quantum efficiency of the device is only 40-62.5%. The TADF mechanism utilizes a TADF having a small singlet-triplet energy level difference (. DELTA.E)_ST) The triplet excitons of the organic small molecule material can be converted into the singlet excitons through a reverse system cross-over (RISC) process under the environment thermal energy. Theoretically, the quantum efficiency in the device can reach 100%, but the efficiency roll-off is larger at high brightness, so that the application of the device in full-color display and white light illumination is limited. The TADF molecules are mainly used as guest materials to be doped in wide-bandgap host materials to realize high-efficiency thermally-activated delayed fluorescence (see J.Am.chem.Soc.2012,134, 14706; Nature,2012,492,234; Mater.Horiz.,2014,1, 264).

Unlike conventional fluorescent molecular localized state (LE) luminescence, TADF emission results primarily from the transition of the Intramolecular Charge Transfer (ICT) state. Since most TADF light-emitting molecular structures take the form of electron donor (D: donor) groups linked to electron acceptor (A; acceptor) groups either by conjugation or non-conjugation, so-called D-A structures (Structure 1), where the electron donor and electron acceptor groups are spatially separated, such molecules are defined as: and (3) an isolated D-A structure. The D-A structure is beneficial to realizing the spatial separation of the Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO) of molecules, thereby easily obtaining the TADF luminescence. Furthermore, the regulation of the peak position (wavelength) of the emission spectrum, i.e., the emission color, is easily achieved based on the D-A type structure because the structures of the electron donor and the electron acceptor and the relative electron-gaining and losing abilities are easily optimized. However, the structure D-a shown in structure 1 easily causes configuration and conformation changes when the molecule is in a ground state and an excited state, and generates abundant molecular vibrational modes, so that the emission spectrum band of the TADF molecule based on structure 1 is broad, and the half-peak width of the emission spectrum of most of such luminescent molecules exceeds 100 nm. The broader spectrum, while advantageous for illumination applications, does not meet the high color purity requirements of the display field. Whereas the most important use of OLED emission is in display, narrow spectral design (i.e., small half-peak width) of TADF materials is essential.

Structure 1.D-A type molecular structure

In recent years it has been reported (see Angew. chem.2018,130, 11486; J.am. chem.Soc.,2018,140,1195; adv.Mater.2016,28,2777; CN 109155368A; WO2016/152544A 1; WO2017/188111A 1; WO2018/150832A 1; WO2018/186374A 1; WO2018/216990A1) that luminescent compounds based on three-coordinated B (boron) are structurally characterized in that the luminescent compounds contain at least one B atom coordinated to three benzene rings to form a very rigid chromophore core structure and that the three benzene rings coordinated to B are covalently linked to N, such molecules being referred to as B-N complexes (Structure 2), i.e. the compounds are luminescent compounds formed by aromatic amine-based organic molecules coordinated to B.

Structure 2. molecular model structure based on three-coordination B-N complex

The molecular orbital of the former line of the three-coordination B complex has a characteristic that the Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO) are distributed in a coordination system in an alternating distribution (namely a so-called resonance structure), B is on the LUMO orbital, and N is on the HOMO orbital. Due to the unique HOMO and LUMO alternate-population electronic structure (resonance structure), the B-N complex enables the material to have excited state charge transfer and TADF luminescence performance (the molecules are defined as resonance D-A molecules), and very importantly, the emission spectrum band is narrow, and the half-peak width of the emission spectrum can reach about 20 nm. Based on the compounds, the high-performance blue light or sky blue light (the peak value of a luminescent light spectrum is between 450-490 nm) organic electroluminescent devices can be prepared, and the electroluminescent spectrum is very narrow (the half-peak width is about 25 nm). However, there has been no report on the preparation of materials with narrow emission spectra, such as green light (emission peak position between 520-535 nm) and red light (emission peak position between 625-640 nm), based on such resonance type B-N coordination structure. The main reason for this is that, although molecules having emission peaks in the green or red region can be obtained by expanding the degree of conjugation of aromatic amine, the expansion of the conjugated system destroys the electronic structure in which HOMO and LUMO are alternately arranged, and therefore the emission spectrum becomes broad, and a narrow-spectrum emission material cannot be obtained.

Therefore, there is still a need for new green and red organic electroluminescent materials with narrow spectral emission characteristics.

Disclosure of Invention

In order to overcome the defect that the emission spectrum of the existing green and red organic electroluminescent materials is too wide, the disclosure provides an organic compound, a composition and an organic electroluminescent device which can emit light in a green to red region and have a narrow-spectrum TADF (TADF) light-emitting characteristic.

The present disclosure provides a boron-nitrogen compound having a structure represented by formula I or II,

R¹independently at each occurrence H, D (deuterium), fluorine, CN, C₁～C₂₀Alkyl radical, C₁～C₂₀Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^aSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl, substituted with one or more R^aSubstituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R^aA substituted diphenylamine group;

e is a single bond or

R¹¹And R²²Independently for each occurrence H, D (deuterium), C₁～C₆Alkyl or C₁～C₆An alkoxy group;

r is as follows:

H、C₁～C₂₀alkyl radical, C₁～C₂₀Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^dSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl or substituted by one or more R^dSubstituted 5-to 18-membered heteroaryl;

R⁴、R⁵and R⁶Independently at each occurrence H, D (deuterium), fluorine, CN, C₁～C₂₀Alkyl radical, C₁～C₂₀Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^dSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl or substituted by one or more R^dSubstituted 5-to 18-membered heteroaryl;

R^aindependently at each occurrence, D (deuterium), fluoro, CN, C₁～C₁₂Alkyl radical, C₁～C₁₂Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^bSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl, substituted by oneOr a plurality of R^bSubstituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R^bA substituted diphenylamine group;

R^bindependently at each occurrence, D (deuterium), fluoro, CN, C₁～C₁₂Alkyl radical, C₁～C₁₂Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^cSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl, substituted with one or more R^cSubstituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R^cA substituted diphenylamine group;

R^cindependently at each occurrence, D (deuterium), fluoro, CN, C₁～C₁₂Alkyl radical, C₁～C₁₂Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^dSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl, substituted with one or more R^dSubstituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R^dA substituted diphenylamine group;

R^dindependently at each occurrence, D (deuterium), fluorine, C₁～C₁₂Alkyl radical, C₁～C₁₂Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals or by one or more R^eSubstituted C₆～C₁₄An aryl group;

R^eindependently at each occurrence, D (deuterium), fluorine, C₁～C₁₂Alkyl radical, C₁～C₁₂Alkoxy radical, C₃-C₁₀Cycloalkyl, or C₆～C₁₄An aryl group;

the above alkyl, alkoxy, cycloalkyl, aryl, heteroaryl groups are optionally substituted with one or more substituents selected from: fluorine, -CN, C₁-C₁₂Alkyl radical, C₁-C₁₂Alkoxy radical, C₁-C₁₂Haloalkyl, C₂-C₆Alkenyl radical, C₃-C₁₀Cycloalkyl radical, C₆-C₁₄Aryl, or 5-to 18-membered heteroaryl.

In another aspect, the present disclosure provides an organic electroluminescent composition comprising the above boron nitrogen compound. Further, the present disclosure also provides an organic electroluminescent composition comprising the above boron-nitrogen compound and a host material.

In still another aspect, the present disclosure provides an organic electroluminescent device comprising the above boron nitrogen compound or organic electroluminescent composition.

In yet another aspect, the present disclosure provides a method for preparing a boron-nitrogen compound of formula I or II as described above, comprising the steps as shown in reaction formulas (1) and (2) below:

in the reaction formula (1), a boron-nitrogen parent nucleus compound containing a carbazole skeleton is taken as a reactant, the reactant is dissolved in an organic solvent, heating and refluxing are carried out in the presence of a catalyst, and a hydrogen atom at a para position of a boron atom of a benzene ring is activated and substituted by boron ester;

introducing an electron-withdrawing group onto the boron-nitrogen skeleton by utilizing a Suzuki reaction in the reaction formula (2), wherein the introduced electron-withdrawing group is positioned at the para position of a B atom of a benzene ring B in the boron-nitrogen skeleton;

in equation (2), ArX is any one of the following three molecules:

wherein

X is Br or Cl;

R¹、R⁴、R⁵、R⁶、R¹¹、R²²r is as defined above.

Drawings

To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below, and it is apparent that the drawings in the following description relate only to some embodiments of the present disclosure and are not limiting to the present disclosure.

Fig. 1 is a schematic structural view of a device used in effect embodiment 2, where 1 is an ITO anode, 2 is a hole injection layer, 3 is a hole transport layer, 4 is a light emitting layer, 5 is an electron transport layer, 6 is an electron injection layer, and 7 is a metal cathode.

FIG. 2 shows photoluminescence spectra of a doped thin film of a compound BN-66, wherein the composition of the doped thin film is H1-1(97 wt.%) BN-66(3 wt.%).

FIG. 3 is an electroluminescence spectrum of a doped thin film of the compound BN-66 in effect example 2, wherein the composition of the doped thin film is H1-1(97 wt%) BN-66(3 wt%).

FIG. 4 is a temperature swing time resolved spectrum of a compound BN-66 doped film having the composition H1-1(97 wt%) BN-66(3 wt%).

FIG. 5 is a graph of the external quantum efficiency as a function of luminance for a device doped with a compound BN-66, where the light emitting layer has a doping weight percent content composition H1-1(97 wt%) BN-66(3 wt%).

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure more apparent, the technical solutions of the embodiments of the present disclosure will be described clearly and completely with reference to the drawings of the embodiments of the present disclosure. It is to be understood that the described embodiments are only a few embodiments of the present disclosure, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the disclosure without any inventive step, are within the scope of protection of the invention.

It is to be understood that, without conflict, any and all embodiments of the present invention may be combined with features from any other embodiment or embodiments to arrive at further embodiments. The present invention includes such combinations to yield additional embodiments.

All publications and patents mentioned in this disclosure are herein incorporated by reference in their entirety. Uses or terms used in any publications and patents, as incorporated by reference, conflict with uses or terms used in this disclosure, subject to the uses and terms of this disclosure.

The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood in the art to which the claimed subject matter belongs. In case there are multiple definitions for a term, the definitions herein control.

Unless otherwise specified, when any type of range is disclosed or claimed (e.g., wavelength, half-peak width, and number of substituents), it is intended that each possible value that such range can reasonably encompass is individually disclosed or claimed, including any subranges subsumed therein. Numerical ranges such as 0 to 6, 1-4, 1 to 3, etc., as defined for example in substituents herein, indicate integers within the range, wherein 0-6 is understood to include 0,1, 2, 3,4, 5, 6, as well as 1-4 and 1-3.

The use of "including," "comprising," or "containing" and similar words in this disclosure is intended to mean that the elements listed before the word cover the elements listed after the word and their equivalents, without excluding unrecited elements. The terms "comprising" or "including" as used herein can be open, semi-closed, and closed. In other words, the term also includes "consisting essentially of …," or "consisting of ….

The terms "moiety," "structural moiety," "chemical moiety," "group," "chemical group" as used herein refer to a specific fragment or functional group in a molecule. Chemical moieties are generally considered to be chemical entities that are embedded in or attached to a molecule. It should be understood that as used in this disclosure, a singular form (e.g., "a") may include plural references unless otherwise specified. Unless otherwise indicated, the present disclosure employs standard nomenclature for analytical chemistry, organic synthetic chemistry, and optics, and standard laboratory procedures and techniques. In some cases, standard techniques are used for chemical synthesis, chemical analysis, light emitting device performance detection. The present disclosure employs conventional methods of mass spectrometry, elemental analysis, and the various steps and conditions can be referred to in the art as conventional procedures and conditions, unless otherwise indicated.

The compounds of the present disclosure may contain unnatural proportions of atomic isotopes at one or more of the atoms that constitute such compounds. For example, compounds may be labeled with isotopes such as deuterium (2H). All isotopic variations of the compounds of the present disclosure, whether radioactive or not, are intended to be encompassed within the scope of the present invention.

Reagents and starting materials used in the present disclosure are either commercially available or can be prepared by conventional chemical synthesis methods.

The term "optionally" is used herein to describe a situation in which it may or may not occur. For example, optionally fused to a ring means that it is fused to a ring or is not fused to a ring. For example, the term "optionally substituted" as used herein refers to a substituent that is unsubstituted or has at least one non-hydrogen substituent that does not destroy the luminescent properties possessed by the unsubstituted analog.

In the present disclosure, the number of the "substitution" may be one or more unless otherwise specified; when there are plural, there may be 2, 3 or 4. When the number of the "substitution" is plural, the "substitution" may be the same or different.

In the present disclosure, the position of "substitution" may be arbitrary, unless otherwise specified.

In the present disclosure, unless otherwise specified, the hydrogen or H is hydrogen in natural abundance, i.e., a mixture of isotopes protium, deuterium, and tritium, wherein the abundance of protium is 99.98%.

In the present disclosure, the deuterium is D or²H, also known as deuterium; the abundance of deuterium at deuterium substitution sites is greater than 95%.

Definitions for the terms of the standardization sector can be found in the literature references including Carey and Sundberg "ADVANCED ORGANIC CHEMISTRY 4TH ED." Vols.A (2000) and B (2001), Plenum Press, New York.

In the present specification, groups and substituents thereof may be selected by one skilled in the art to provide stable moieties and compounds. When a substituent is described by a general formula written from left to right, the substituent is also the same asChemically equivalent substituents resulting from writing the formula from right to left are included. For example-CH₂O-is equivalent to-OCH₂-。

The term "halogen" or "halo" as used herein refers to fluorine, chlorine, bromine or iodine. In one embodiment, the halogen or halo is preferably fluoro or fluoro.

In this disclosure, the term "alkyl" as a group or part of another group (e.g., as used in halo-substituted alkyl and the like groups) is intended to include both branched and straight chain saturated aliphatic hydrocarbon groups having the indicated number of carbon atoms. E.g. C₁～C₂₀The alkyl group includes a straight or branched alkyl group having 1 to 20 carbon atoms. As in "C₁～C₆Alkyl is defined to include groups having 1,2, 3,4, 5, or 6 carbon atoms in a straight or branched chain configuration. For example, in the present disclosure, said C₁～C₆Each alkyl group is independently methyl, ethyl, propyl, butyl, pentyl or hexyl; wherein propyl is C₃Alkyl (including isomers such as n-propyl or isopropyl); butyl being C₄Alkyl (including isomers such as n-butyl, sec-butyl, isobutyl, or tert-butyl); pentyl is C₅Alkyl (including isomers such as n-pentyl, 1-methyl-butyl, 1-ethyl-propyl, 2-methyl-1-butyl, 3-methyl-1-butyl, isopentyl, tert-pentyl or neopentyl); hexyl radical is C₆Alkyl (including isomers such as n-hexyl or isohexyl).

"substituted alkyl" refers to an alkyl group substituted at any available point of attachment with one or more substituents, preferably 1 to 4 substituents. The term "haloalkyl" refers to an alkyl group having one or more halo substituents, e.g., halomethyl including but not limited to as-CH₂Br、-CH₂I、-CH₂Cl、-CH₂F、-CHF₂and-CF₃Such a group.

The term "alkoxy" as used herein refers to an alkyl group as defined above, each attached via an oxygen linkage (-O-). The term "substituted alkoxy" refers to a substituted alkyl group as defined above attached via an oxygen linkage.

In the present disclosure, the term "Cn-m aryl" as a group or part of another group refers to a monocyclic or polycyclic aromatic group having n to m ring carbon atoms (the ring atoms being only carbon atoms) with at least one carbocyclic ring having a conjugated pi-electron system. Examples of the above aryl unit include phenyl, biphenyl, naphthyl, anthryl, phenanthryl, indenyl, azulenyl, or fluorenyl and the like. In one embodiment, the aryl group is preferably C_6-14Aryl groups such as phenyl, biphenyl, and naphthyl, more preferably phenyl.

In the present disclosure, the term "n-m membered heteroaryl" as a group or part of another group refers to an aromatic group whose ring atoms are n to m, containing one or more (e.g., 1,2, 3 and 4) heteroatoms selected from nitrogen, oxygen and sulfur, the heteroaryl being a monocyclic, bicyclic, tricyclic or tetracyclic ring system, wherein at least one ring is aromatic. Heteroaryl groups within the scope of this definition include, but are not limited to: acridinyl, carbazolyl, cinnolinyl, quinoxalinyl, pyrazolyl, indolyl, benzotriazolyl, furyl, thienyl, benzothienyl, benzofuryl, quinolyl, isoquinolyl, oxazolyl, isoxazolyl, pyrazinyl, pyridazinyl, pyridyl, pyrimidinyl, pyrrolyl, tetrahydroquinoline, imidazolyl, triazolyl, tetrazolyl, thiazolyl, isothiazolyl, thiadiazolyl, oxadiazolyl, triazinyl, purinyl, pteridinyl, naphthyridinyl, quinazolinyl, phthalazinyl, imidazopyridinyl, imidazothiazolyl, imidazooxazolyl, benzothiazolyl, benzoxazolyl, benzimidazolyl, isoindolyl, indazolyl, pyrrolopyridyl, thienopyridyl, furopyridyl, benzothiadiazolyl, benzooxadiazolyl, pyrrolopyrimidyl, thienofuryl, and thienofuryl. In one embodiment, as preferable examples of the "5 to 18-membered heteroaryl group", furyl, thienyl, pyrrolyl, imidazolyl, thiazolyl, pyrazolyl, oxazolyl, isoxazolyl, isothiazolyl, pyridyl, pyrimidinyl and carbazolyl groups can be cited, and carbazolyl groups are more preferable.

The term "fused" as used herein means that two or more carbocyclic or heterocyclic rings form a polycyclic ring in a common ring-edge manner.

The term C as used herein_n-C_mCycloalkyl means a monocyclic or polycyclic alkyl group having n to m carbon atoms, e.g. C₃-C₁₀Cycloalkyl and C₃-C₆A cycloalkyl group. Examples include adamantyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and bicycloheptyl. In one embodiment, C₃-C₁₀The cycloalkyl group is preferably an adamantyl group or a cyclohexyl group.

The present disclosure provides a method for designing and synthesizing an organic light-emitting molecule having a narrow emission spectrum characteristic with an emission peak position between 490-615nm, which is different from a method in which an electron donor group and an electron acceptor group adopt a separation structure (as shown in structure 1) and a HOMO and LUMO alternately-distributed electron structure (as shown in structure 2) in space. The specific molecular design adopted by the present disclosure is as follows:

structure 3. representative model molecular structures.

Structure 3 presents a representative molecular design model structure provided by the present disclosure, Ar groups are defined as previously described, and the general method and principle of molecular design provided are: an additional pyrimidine derivative electron acceptor group is introduced to a functional skeleton with the characteristic of an HOMO and LUMO alternately populated electronic structure (resonance structure), a certain C (carbon) atom of the introduced pyrimidine derivative is connected with a C atom on the resonance structure group through a single bond, and the additional pyrimidine derivative is covalently connected in a para-position substitution manner with respect to a B atom in the resonance structure (as shown in structure 3). Because the additional pyrimidine derivative C atom is attached to the C of the LUMO orbital population on the resonance moiety, the LUMO orbital of the molecule provided by the present disclosure is formed by the combination of the LUMO orbital of the resonance moiety and the LUMO orbital of the additional pyrimidine derivative acceptor, while the HOMO orbital of the molecule provided by the present disclosure is the same as the HOMO orbital of the resonance moiety in the molecule. Therefore, the organic light-emitting molecule provided by the present disclosure differs from the existing D-a type structure in which the electron donor group and the electron acceptor group are spatially separated and the HOMO and LUMO alternately-populated electronic structure (resonance structure) from the molecular structure to the front-line orbital electronic structure.

The organic light-emitting molecule design method provided by the present disclosure has advantages in that advantages of the separation type D-A structure and the resonance type D-A molecule are combined, and disadvantages of the two types of molecules are overcome. Because the additional pyrimidine derivative acceptor and the B atom adopt a para-position substitution form and the pyrimidine derivative acceptor has stronger electron-withdrawing capability, the intramolecular charge transfer characteristic of the target molecule can be obviously improved, and the strong intramolecular charge transfer characteristic is favorable for adjusting the emission wavelength. The organic luminescent material with narrow emission spectrum with the peak wavelength from 490nm to 630nm, such as the half-width of the emission spectrum less than or equal to 65nm, can be obtained by utilizing the molecular design method provided by the disclosure.

The technical method provided by the disclosure can be used for effectively designing and synthesizing organic molecules which emit light from green light to red light and have the light-emitting characteristic of a narrow-spectrum TADF (TADF), the organic molecules and the composition of the organic molecules and some materials can be used as light-emitting materials to prepare the light-emitting layer of an organic electroluminescent device, and the organic electroluminescent device has the advantages of narrow emission spectrum, high efficiency, high color purity of the device and the like.

The present disclosure provides a boron-nitrogen compound having a structure represented by formula I or II,

R¹independently at each occurrence H, D (deuterium), fluorine, CN, C₁～C₂₀Alkyl radical, C₁～C₂₀Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^aSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl, substituted with one or more R^aSubstituted 5-to 18-membered heteroaryl, diphenylamino, or substitutedOne or more R^aA substituted diphenylamine group;

e is a single bond or

R¹¹And R²²Independently for each occurrence H, D (deuterium), C₁～C₆Alkyl or C₁～C₆An alkoxy group;

r is:

H、C₁～C₂₀alkyl radical, C₁～C₂₀Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^dSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl or substituted by one or more R^dSubstituted 5-to 18-membered heteroaryl;

R⁴、R⁵and R⁶Independently at each occurrence H, D (deuterium), fluorine, CN, C₁～C₂₀Alkyl radical, C₁～C₂₀Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^dSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl or substituted by one or more R^dSubstituted 5-to 18-membered heteroaryl;

R^aindependently at each occurrence, D (deuterium), fluoro, CN, C₁～C₁₂Alkyl radical, C₁～C₁₂Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^bSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl, substituted with one or more R^bSubstituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R^bA substituted diphenylamine group;

R^bindependently at each occurrence, D (deuterium), fluoro, CN, C₁～C₁₂Alkyl radical, C₁～C₁₂Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^cSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl, substituted with one or more R^cSubstituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R^cA substituted diphenylamine group;

R^cindependently at each occurrence, D (deuterium), fluoro, CN, C₁～C₁₂Alkyl radical, C₁～C₁₂Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^dSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl, substituted with one or more R^dSubstituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R^dA substituted diphenylamine group;

R^dindependently at each occurrence, D (deuterium), fluorine, C₁～C₁₂Alkyl radical, C₁～C₁₂Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals or by one or more R^eSubstituted C₆～C₁₄An aryl group;

R^eindependently at each occurrence, D (deuterium), fluorine, C₁～C₁₂Alkyl radical, C₁～C₁₂Alkoxy radical, C₃-C₁₀Cycloalkyl, or C₆～C₁₄An aryl group;

the above alkyl, alkoxy, cycloalkyl, aryl, heteroaryl groups are optionally substituted with one or more substituents selected from: fluorine, -CN, C₁-C₁₂Alkyl radical, C₁-C₁₂Alkoxy radical, C₁-C₁₂Haloalkyl, C₂-C₆Alkenyl radical, C₃-C₁₀Cycloalkyl radical, C₆-C₁₄Aryl, or 5-to 18-membered heteroaryl.

In one embodiment of the disclosure, R¹Independently at each occurrence H, F, CF₃、C₁～C₂₀Alkyl radical, C₁～C₂₀Alkoxy, cyclohexyl, adamantyl, phenyl, naphthyl, substituted with one or more R^aSubstituted phenyl, carbazolyl, substituted with one or more R^aSubstituted carbazolyl, diphenylamine, or substituted by one or more R^aSubstituted diphenylamine group, the R^aIs selected from C₁～C₆Alkyl radical, C₁-C₆Fluoroalkyl and C₁～C₆An alkoxy group.

In one embodiment of the disclosure, R⁴、R⁵And R⁶Independently at each occurrence H, F, CF₃、C₁～C₂₀Alkyl radical, C₁～C₂₀Alkoxy, cyclohexyl, adamantyl, phenyl, naphthyl, substituted with one or more R^dSubstituted phenyl, carbazolyl, substituted with one or more R^dSubstituted carbazolyl group, said R^dIs selected from C₁～C₁₂Alkyl radical, C₁-C₁₂Fluoroalkyl, C₁～C₁₂Alkoxy, phenyl and substituted by one or more R^eSubstituted phenyl, said R^eIs selected from C₁～C₆Alkyl radical, C₁-C₆Fluoroalkyl and C₁～C₆An alkoxy group.

In one embodiment of the disclosure, R¹¹And R²²Each occurrence is independently H, methyl, methoxy or CF₃。

In one embodiment of the disclosure, the promoiety molecular orbital of the compounds of formula I and II has the following characteristics:

HOMO and LUMO are distributed in an alternating manner on ring atoms of ring c11, ring c12, ring c13, ring c14, ring B1 and one B and two N simultaneously connected to three of the rings in formula I, two N in formula I are distributed with HOMO, and B atom, ring m1 and ring ph1 are distributed with LUMO;

HOMO and LUMO are distributed in an alternating manner on the ring atoms of ring c21, ring c22, ring c23, ring c24, ring B2 and on one B and two N which are simultaneously connected to three of the rings in formula II, with the HOMO distributed on two N in formula II and the LUMO distributed on the B atom, ring m2 and ring ph 2.

In one embodiment of the disclosure, in formula I or II, E is a single bond or a benzene ring;

R¹independently for each occurrence is H, methyl, t-butyl, phenyl, 4-tolyl, 3, 5-xylyl, 4-t-butylphenyl, 3, 5-di-t-butylphenyl, diphenylamino, di (p-tolyl) amino, or di (p-t-butylphenyl) amino;

R¹¹and R²²Is H;

r is H or

R⁴And R⁵Identical and are tert-butyl, phenyl, 4-tolyl, 3, 5-xylyl, 4-tert-butylphenyl, 3, 5-di-tert-butylphenyl, 4-C₁～C₁₀Alkoxyphenyl, 3-C₁～C₁₀Alkoxyphenyl, or 3, 5-di-C₁～C₁₀An alkoxyphenyl group;

R⁶is H.

In one embodiment of the present disclosure, the emission spectra of the compounds of formula I and II have emission peaks at 630nm and half-widths of emission spectra of 60nm or less.

In one embodiment of the present disclosure, the emission spectra of the compounds of formulae I and II have an emission peak position of 500-600nm and an emission spectrum half-peak width of 60nm or less.

In one embodiment of the present disclosure, the molecular structure of the compounds of formulae I and II satisfies the following definitions: wherein E in formula I is a single bond or

Wherein in formula II

Is composed of

Wherein in formulae I and II

Is any one of the following groups:

wherein in formulae I and II

Is any one of the following groups:

in one embodiment of the disclosure, the compounds of formulae I and II are any one of the following:

the present disclosure provides a method for preparing a boron-nitrogen compound of the above formula I or II, which comprises the steps as shown in the following reaction formulas (1) and (2):

in the reaction formula (1), a boron-nitrogen parent nucleus compound containing a carbazole skeleton is taken as a reactant, the reactant is dissolved in an organic solvent, heating and refluxing are carried out in the presence of a catalyst, and a hydrogen atom at a para position of a boron atom of a benzene ring is activated and substituted by boron ester;

introducing an electron-withdrawing group onto the boron-nitrogen skeleton by utilizing a Suzuki reaction in the reaction formula (2), wherein the introduced electron-withdrawing group is positioned at the para position of a B atom of a benzene ring B in the boron-nitrogen skeleton;

in equation (2), ArX is any one of the following three molecules:

wherein

X is Br or Cl;

R¹、R⁴、R⁵、R⁶、R¹¹、R²²r is as defined above.

The compounds of formulae I and II of the present disclosure may be prepared according to chemical synthesis methods conventional in the art, and the procedures and conditions thereof may refer to those of analogous reactions in the art. The present disclosure provides a method of preparing a compound of formula I and II, which may include the following scheme:

wherein

The present disclosure also provides an organic electroluminescent device comprising an anode, a light-emitting layer, an optional hole injection layer, an optional hole transport layer, an optional electron injection layer, and a cathode, wherein at least one of the light-emitting layer, the electron injection layer, the electron transport layer, the hole transport layer, and the hole injection layer comprises the boron nitrogen compound as described above. The organic electroluminescent device of the present disclosure may further include an optional hole blocking layer, an optional electron blocking layer, and an optional capping layer, etc. In one embodiment, the organic electroluminescent device has a structure as shown in fig. 1, in which 1 is an ITO anode, 2 is a hole injection layer, 3 is a hole transport layer, 4 is a light emitting layer, 5 is an electron transport layer, 6 is an electron injection layer, and 7 is a metal cathode.

In one embodiment of the present disclosure, the boron-nitrogen compound represented by formula I or II is used for preparing a light emitting layer in an organic electroluminescent device.

In one embodiment of the present disclosure, the boron-nitrogen compound represented by formula I or II is used for preparing a light emitting layer in an organic electroluminescent device, and the molecular structures of the compounds represented by formula I and II are defined as follows:

wherein E in formula I is a single bond or

Wherein in formula II

Is composed of

Wherein in formulae I and II

Is any one of formulas B-1 to B-100;

wherein in formulae I and II

Is any one of formulas M-1 to M-87.

In one embodiment of the present disclosure, the boron-nitrogen compound represented by the formulas BN-1 to BN-584 is used for preparing a light emitting layer in an organic electroluminescent device.

In one embodiment of the present disclosure, the organic electroluminescent device further includes a substrate, and an anode layer, an organic light emitting functional layer, and a cathode layer sequentially formed on the substrate; the organic light-emitting functional layer comprises a light-emitting layer containing the boron-nitrogen compound, and can further comprise any one or a combination of a plurality of hole injection layers, hole transport layers, electron blocking layers, hole blocking layers, electron transport layers and electron injection layers.

The present disclosure provides an organic electroluminescent composition comprising a boron nitrogen compound represented by formula I or II (as a dopant material) and a host material; the host material is capable of transporting electrons and/or holes and has a triplet excited state energy that is higher than or close to the triplet excited state energy of the dopant material.

In one embodiment of the present disclosure, the host material in the organic electroluminescent composition may be a carbazole derivative and/or a carboline derivative represented by formulae (H-1) to (H-6). The organic electroluminescent composition preferably contains 0.3-30.0 wt% (weight percentage) of any one compound of the formula I or II as a doping material, and the remaining 99.7-70.0 wt% of the components are a host material composed of 1-2 compounds of the formulae (H-1) to (H-6). In one embodiment, the host material contains 2 compounds of formulae (H-1) to (H-6) in a weight ratio of 1:5 to 5: 1.

Wherein X₁、Y₁And Z₁Is CH or N, and X₁、Y₁And Z₁At most one of them is N.

Wherein R is^1HAnd R^2HIndependently any of the following groups:

wherein X₂、Y₂And Z₂Is CH or N, and X₂、Y₂And Z₂At most one of them is N; wherein R is^aHAnd R^bHIndependently H, C₁-C₂₀Alkyl radical, C₁-C₂₀Alkoxy radical, C₆-C₂₀Aryl radical, C₁-C₂₀Alkyl substituted C₆-C₂₀Aryl or C₁-C₂₀Alkoxy-substituted C₆-C₂₀And (4) an aryl group.

In one embodiment of the present disclosure, the host material in the organic electroluminescent composition is 1-2 of compounds H1-1 to H1-427; the organic electroluminescent composition contains 0.3-30.0 wt% (weight percentage) of any compound shown in formula I or II, and the rest 99.7-70.0 wt% of the components are 1-2 compounds in compounds H1-1 to H1-427. In a preferred embodiment of the present disclosure, the organic electroluminescent composition contains 2 compounds of the formulae H1-1 to H1-427 as host materials in a weight ratio of 1:5 to 5: 1.

In one embodiment of the present disclosure, the doping material in the organic electroluminescent composition is any one of compounds represented by formula I or II (with a content of 0.3 wt% to 30.0 wt%); the main body material (the content is 99.7 wt% -70.0 wt%) is composed of any one of 1,3, 5-triazine derivatives shown in formulas Trz1-A, Trz2-A and Trz3-A and any one of compounds shown in formulas H-1 to H-6. In a preferred embodiment, the weight ratio of the 1,3, 5-triazine derivative represented by Trz1-A, Trz2-A or Trz3-A to the compound represented by H-1, H-2, H-3, H-4, H-5 or H-6 in the host material is 1:5 to 5: 1.

Wherein R is^1a、R^1b、R^2a、R^2b、R^3aAnd R ^3b1 or 2 of (a) are independently R^TzThe others are the same or different and independently hydrogen, deuterium, C₁-C₈Alkyl radical, C₁-C₈Alkoxy radical, C₆-C₁₈Aryl radical, C₁-C₈Alkyl substituted C₆-C₁₈Aryl or C₁-C₈Alkoxy-substituted C₆-C₁₈Aryl of (a); r^TzIs any one of groups Tz-n (n ═ 1 to 61) shown by the following formula:

in one embodiment of the present disclosure, the doping material in the organic electroluminescent composition is any one of compounds represented by formula I or II (with a content of 0.3 wt% to 30.0 wt%); the main body material (the content is 99.7wt-70.0 wt%) is composed of any one of 1,3, 5-triazine derivatives shown in formulas TRZ-1 to TRZ-56 and any one of carbazole or carboline derivatives shown in formulas H1-1 to H1-427. In a preferred embodiment, the weight ratio between the 1,3, 5-triazine derivative and the carbazole or carboline derivative in the host material is from 1:5 to 5: 1.

The present disclosure provides a use of the organic electroluminescent composition as described above as an organic electroluminescent material. In one embodiment of the present disclosure, the organic electroluminescent composition is used for preparing a light emitting layer in an organic electroluminescent device.

The present disclosure also provides an organic electroluminescent device comprising an anode, a light-emitting layer, an optional hole injection layer, an optional hole transport layer, an optional electron injection layer and a cathode, wherein at least one of the light-emitting layer, the electron injection layer, the electron transport layer, the hole injection layer comprises the organic electroluminescent composition as described above. In a preferred embodiment, the light-emitting layer of the organic electroluminescent device comprises an organic electroluminescent composition as described above.

In one embodiment of the present disclosure, the organic electroluminescent composition is a light-emitting layer, and the light-emitting layer emits light based on the energy transfer from the host material to any of the compounds represented by formula I or II or the carrier capture of the light-emitting material itself.

In one embodiment of the present disclosure, the organic electroluminescent composition is a light-emitting layer; the host material in the organic electroluminescent composition can be carbazole derivatives and/or carboline derivatives shown in formulas (H-1) to (H-6). In a preferred embodiment, the organic electroluminescent composition comprises 0.3 to 30.0 wt% of any one of the compounds represented by formula I or II, and the remaining 99.7 to 70.0 wt% of the component is a host composed of 1 to 2 compounds of formulae (H-1) to (H-6). For example, when the main body contains 2 kinds of compounds of the formulae (H-1) to (H-6), the weight ratio of the two compounds is 1:5 to 5: 1.

In one embodiment of the present disclosure, the organic electroluminescent composition is a light-emitting layer; the main materials in the composition are 1-2 of the compounds H1-1 to H1-427. In a preferred embodiment, the organic electroluminescent composition comprises 0.3-30.0 wt% of any one of the compounds represented by formula I or II, and the remaining 99.7-70.0 wt% of the components are 1-2 of the compounds H1-1 to H1-427. For example, when 2 compounds of the formulae H1-1 to H1-427 are present in the composition, the weight ratio of the two compounds is 1:5 to 5: 1.

In one embodiment of the present disclosure, the organic electroluminescent composition is a light-emitting layer; the doping material in the organic electroluminescent composition is any one compound shown in a formula I or II (the content is 0.3 wt% -30.0 wt%); the main body material (the content is 99.7 wt% -70.0 wt%) is composed of any one of 1,3, 5-triazine derivatives shown in formulas Trz1-A, Trz2-A and Trz3-A and any one of compounds shown in formulas H-1 to H-6. For example, in the host material, the weight ratio of the 1,3, 5-triazine derivative represented by Trz1-A, Trz2-A or Trz3-A to the compound represented by H-1, H-2, H-3, H-4, H-5 or H-6 is 1:5 to 5: 1.

In one embodiment of the present disclosure, the organic electroluminescent composition is a light-emitting layer; the doping material in the organic electroluminescent composition is any one compound shown in a formula I or II (the content is 0.3 wt% -30.0 wt%); the main body material (the content is 99.7wt-70.0 wt%) is composed of any one of 1,3, 5-triazine derivatives shown in formulas TRZ-1 to TRZ-56 and any one of carbazole or carboline derivatives shown in formulas H1-1 to H1-427. For example, in the host material, the weight ratio between the 1,3, 5-triazine derivative and the carbazole or carboline derivative is 1:5 to 5: 1.

In one embodiment of the present disclosure, the organic electroluminescent composition is a light-emitting layer; the doping material in the organic electroluminescent composition is any one compound shown in a formula BN-1 to BN-584 (the content is 0.3wt percent to 30.0wt percent); the main body material (the content is 99.7wt-70.0 wt%) is composed of any one of 1,3, 5-triazine derivatives shown in formulas TRZ-1 to TRZ-56 and any one of carbazole or carboline derivatives shown in formulas H1-1 to H1-427. For example, in the host material, the weight ratio between the 1,3, 5-triazine derivative and the carbazole or carboline derivative is 1:5 to 5: 1.

In one embodiment of the present disclosure, the organic electroluminescent device further includes a substrate, and an anode layer, an organic light emitting functional layer, and a cathode layer sequentially formed on the substrate; the organic light-emitting functional layer comprises a light-emitting layer containing the organic electroluminescent composition, and can further comprise any one or a combination of a plurality of hole injection layers, hole transport layers, electron blocking layers, hole blocking layers, electron transport layers and electron injection layers.

The present disclosure provides an application of the organic electroluminescent device in an organic electroluminescent display or an organic electroluminescent lighting source.

The present disclosure provides a method for designing a molecular structure of an organic light emitting material, which has the following advantages: combines the advantages of the separated D-A structure and the resonance D-A molecule, and overcomes the defects of the two molecules. Based on the molecular design method, the defect that the emission spectrum of the existing green and red light organic electroluminescent material is too wide can be effectively overcome, and a technical method for designing, synthesizing and preparing organic molecules which emit light in a green-red region or even near infrared and have the characteristic of narrow-spectrum light emission is provided; and further provides an organic compound which emits light in a green light region to a red light region and has a narrow spectrum light-emitting characteristic as shown in formulas I and II, a composition and application thereof in the field of organic electroluminescence. The organic molecules and the composition of the organic molecules and some materials provided by the disclosure can be used as luminescent materials to prepare luminescent layers of organic electroluminescent devices, and the organic electroluminescent devices prepared by the method have the advantages of narrow emission spectrum (relative to the electroluminescent spectrum of a separated D-A structure luminescent material), high efficiency and the like.

The present disclosure provides a synthetic method of coupling a1, 3-dicarbazole (or its derivative) benzene-based tridentate B complex with a pyrimidine derivative, which is advantageous in that a pyrimidine derivative group having an electron-withdrawing property can be coupled with a C atom occupied by a LUMO orbital in a tridentate B resonance skeleton, and thus a pyrimidine derivative group having a conjugated structure and a strong electron-withdrawing property can be efficiently introduced into the tridentate B resonance skeleton based on the synthetic method.

According to the conventional synthesis thought, researchers in the field usually synthesize molecules containing a three-coordinate B resonance skeleton and a pyrimidine derivative group according to the following reaction scheme (3), and in the following reaction scheme, Ar is a pyrimidine derivative, and the experimental research results prove that a three-coordinate B structure cannot be formed according to the following reaction scheme, that is, under the condition, the boron atom cannot coordinate with 1, 3-dicarbazole (or its derivative) benzene, and the target product cannot be obtained according to the reaction scheme. The main reason is that when the pyrimidine derivative with a strong electron-withdrawing group exists, the para-carbon atom is in an electron-deficient state, that is, the electron cloud density is low, so that the carbon atom cannot form a covalent bond with a boron atom.

R¹And Ar is as defined above.

In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be described below clearly and completely with reference to the accompanying drawings. It is to be understood that the described embodiments are only a few embodiments of the present disclosure, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the disclosure without any inventive step, are within the scope of protection of the invention.

The present disclosure is further illustrated by the following examples, but is not intended to be limited thereby in the scope of the examples described. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.

The Mass spectrometric data (Mass Spectra: MS) with a relative molecular weight below 1000 were measured by ITQ1100 ion trap gas chromatograph-Mass spectrometer from Thermo Fisher, and the Mass spectrometric data with a relative molecular weight above 1000 were measured by Autoflex matrix-assisted laser desorption time-of-flight Mass spectrometer from Bruker. The machine used for Elemental analysis of the final product was Flash EA1112 from Elemental analysis.

The UV-visible absorption spectrum of the sample film was measured by a model LAMBDA 35 UV-visible spectrophotometer from Perkinelmer. The fluorescence spectrum was measured by an RF-5301PC fluorescence photometer of Shimadzu corporation, Japan, and the excitation wavelength selected at the time of the test was the maximum absorption wavelength.

Specifically, the adopted raw material-1 comprises the following molecules:

specifically, the adopted raw material-2 comprises the following molecules:

specifically, the adopted raw material-3 comprises the following molecules:

the basic process route of the compound synthesis related by the invention is as follows, and the reaction is divided into four steps. The first two steps are synthesized into BNCz mother nucleus; the most central to the synthesis of the final product is the successful preparation of the precursor BN-Bpin. Firstly, a synthesized boron-nitrogen parent nucleus containing a carbazole skeleton is taken as a substrate, the substrate is dissolved in tetrahydrofuran, a reaction system is heated and refluxed under the condition that 1% of equivalent of main catalyst methoxy (cyclooctadiene) iridium dimer and 2% of equivalent of cocatalyst 4,4 '-di-tert-butyl-2, 2' -bipyridyl are added, boron atoms substitute benzene rings to activate para-hydrogen atoms and are substituted by boron ester. Then, only one-step simple Suzuki reaction is needed to flexibly obtain various electron-withdrawing substituted compounds. The specific synthesis process comprises the following steps:

wherein

Synthetic examples

In the first step, 60ml of an anhydrous DMF (N, N-dimethylformamide) solution containing 35.2mmol of a carbazole derivative was slowly dropped into 50ml of an anhydrous DMF solution containing 5.4g of potassium tert-butoxide (48.0mmol), and after stirring at room temperature for 2 hours, 20ml of an anhydrous DMF solution containing 3.1g of 2-bromo-1, 3-difluorobenzene (16.0mmol) was dropped thereinto. The reaction was stirred at 140 ℃ for 24 hours, then cooled to room temperature and poured into ice water. The white solid was suction filtered off, dried in vacuo and then further purified by column chromatography using a mixed eluent of dichloromethane/petroleum ether to give intermediate BrNCz as a white solid.

Second, 19.4mL of a solution of tert-butyllithium in n-hexane (25.2mmol) are slowly added to a solution of 12.6mmol of intermediate BrNCz in 100mL of tert-butylbenzene (-30 ℃) under a nitrogen atmosphere. The temperature was slowly raised to 60 ℃ and after stirring for 2 hours, n-hexane was removed in vacuo, then cooled to-30 ℃ and 2.4mL of boron tribromide (6.3mmol) were added and the reaction mixture was stirred at room temperature for 1 hour. 15.6mL of N, N-diisopropylethylamine (91.1mmol) were then added at 0 ℃ and the reaction mixture was allowed to warm to 130 ℃ and stirred for a further 5 hours before cooling to room temperature. To the reaction mixture was added 5ml of methanol to quench the residual BBr₃. The reaction was concentrated in vacuo and purified by column chromatography with dichloromethane/petroleum ether mixture eluent to afford BNCz mother nuclei.

Third, a boron nitrogen raw material containing a carbazole skeleton (6.5mmol), 1.7g of pinacol diboron (6.5mmol) were added to tetrahydrofuran (60mL) at room temperature, the mixture was bubbled with nitrogen for 10 minutes, and 34.9mg of 4,4 '-di-tert-butyl-2, 2' -bipyridine (0.13mmol) and 43.1mg of methoxy (cyclooctadiene) iridium dimer (0.065mmol) were added under high-flow nitrogen. After stirring for 10 minutes, the mixture was heated to reflux and stirred for 24 hours. And after the reaction system is cooled to room temperature, directly carrying out reduced pressure concentration and column chromatography purification to obtain the precursor BN-Bpin.

In a fourth step, Ar-X (Ar is defined as bromine, X is defined as above) (0.6mmol), BN-Bpin (0.5mmol), 0.14g of potassium carbonate (1mmol) and water (2mL) are added to tetrahydrofuran (16mL), the mixture is bubbled with nitrogen for 10 minutes and 28.9mg of tetrakis (triphenylphosphine) palladium (0.025mmol) is added under a high flow of nitrogen. The mixture was heated to reflux and stirred for 12 hours. After the reaction system was cooled to room temperature, the reaction mixture was extracted with dichloromethane and water, and the organic phase was dried by heating under vacuum and then purified by column chromatography to obtain the target product BN-n (n ═ 1-756).

The experimental details of the synthesis examples are illustrated by the compound BN-66: in the first step, 60ml of an anhydrous DMF (N, N-dimethylformamide) solution containing 9.8g of 3, 6-di-tert-butylcarbazole (35.2mmol) was slowly added dropwise to a 50ml anhydrous DMF solution containing 5.4g of potassium tert-butoxide (48.0mmol), and after stirring at room temperature for 2 hours, 20ml of an anhydrous DMF solution containing 3.1g of 2-bromo-1, 3-difluorobenzene (16.0mmol) was added dropwise thereto. The reaction was stirred at 140 ℃ for 24 hours, then cooled to room temperature and poured into ice water. The white solid was suction filtered off, dried in vacuo and then further purified by column chromatography using a mixed eluent of dichloromethane/petroleum ether to give 10.5g of intermediate BrNCz as a white solid (92% yield).

Second, 19.4mL of a solution of tert-butyllithium in n-hexane (25.2mmol) were slowly added to a solution of intermediate BrNCz 9.0g (12.6mmol) in 100mL of tert-butyl-benzene (-30 ℃ C.) under a nitrogen atmosphere. The temperature was slowly raised to 60 ℃ and after stirring for 2 hours, the n-hexane was removed in vacuo, then cooled to-30 ℃ and 2.4mL of boron tribromide (6.3mmol) were added and the reaction mixture was stirred at room temperature for 1 hour. 15.6mL of N, N-diisopropylethylamine (91.1mmol) were then added at 0 ℃ and the reaction mixture was allowed to warm to 130 ℃ and stirred for a further 5 hours before cooling to room temperature. To the reaction mixture was added 5ml of methanol to quench the residual BBr₃. The reaction was concentrated in vacuo and purified by column chromatography with a mixture of dichloromethane/petroleum ether eluent to give 2.9g of BNCz mother nuclei as a yellow solid (35% yield) (experiment can be repeated multiple times to enrich the starting material).

Third, 4.2g of BNCz (6.5mmol), 1.7g of pinacol diboron (6.5mmol) were added to tetrahydrofuran (60mL) at room temperature, the mixture was bubbled with nitrogen for 10 minutes, and 34.9mg of 4,4 '-di-tert-butyl-2, 2' -bipyridine (0.13mmol) and 43.1mg of methoxy (cyclooctadiene) iridium dimer (0.065mmol) were added under high-flow nitrogen. After stirring for 10 minutes, the mixture was heated to reflux and stirred for 24 hours. After the reaction system is cooled to room temperature, the reaction system is directly decompressed and concentrated, and column chromatography purification is carried out, so as to obtain 4.5g of BN-Bpin (the yield is 90%).

In a fourth step 187mg 4-bromophenyl-2, 6-diphenylpyrimidine (0.6mmol), 383mg BN-Bpin (0.5mmol), 0.14g potassium carbonate (1mmol) and water (2mL) were added to tetrahydrofuran (16mL), the mixture was bubbled with nitrogen for 10 minutes, and 28.9mg tetrakis (triphenylphosphine) palladium (0.025mmol) was added under high-flow nitrogen. The mixture was heated to reflux and stirred for 12 hours. After the reaction system was cooled to room temperature, the reaction mixture was extracted with dichloromethane and water, and the organic phase was dried by heating under vacuum and then purified by column chromatography to obtain 252mg of the target product BN-66 as a yellow solid (yield 58%).

TABLE 1 elemental analysis (C, H and N% in compound), mass spectrometry for molecular weight and synthesis yield data (total yield of four-step reaction) for compounds BN-1 through BN-584.

Effect example 1

The luminescent molecular structures employed in the comparative examples are as follows:

the compounds represented by the formulas BN-1 to BN-584 are the molecular structures of the materials provided by the present disclosure (the specific molecular structures are shown as above), and the compounds represented by BN-R-1 to BN-R-7 are the molecular structures of comparative materials. A doped thin film (thickness of 150 ± 15nm) was prepared using any one of the compounds represented by the formula BN-n (n ═ 1-584) as a doped luminescent material and H-1 as a host material, respectively, and the doped luminescent material was doped at a concentration of 3 wt% (weight percentage concentration), and then the doped thin film was subjected to emission spectrum measurement, and the measurement results are shown in table 2.

Comparison of the luminescence peak positions of the luminescent compounds provided by the present disclosure listed in table 2 with the luminescence peak positions of the corresponding comparative compounds shows that the luminescence peak positions of the luminescent compounds provided by the present disclosure are red-shifted by 5 to 57nm, i.e., shifted toward long wavelengths by 5 to 57nm, compared to the luminescence peak positions of the corresponding comparative compounds. The above effect examples demonstrate that the emission peak of the boron-nitrogen compound of the present disclosure is significantly red-shifted with respect to its isomers without significant deterioration of the half-width of the emission spectrum (still narrow), and thus the luminescent molecule design principle and method provided by the present disclosure are effective in providing a luminescent material having a narrow emission peak in the green to red regions.

Table 2 BN-n (n ═ 1-584) emission spectrum test parameters.

Electroluminescent device embodiments

Device effects some of the material molecular structures involved in the examples are as follows:

the following embodiments of the electroluminescent device prepared by using the material disclosed by the invention have the following specific device preparation processes:

(1) substrate treatment: the transparent ITO glass is used as a substrate material for preparing a device, ultrasonic treatment is carried out for 30min by using 5% ITO washing liquor, then ultrasonic washing is carried out by using distilled water (2 times), acetone (2 times) and isopropanol (2 times) in sequence, and finally the ITO glass is stored in the isopropanol. Before each use, the surface of the ITO glass is carefully wiped by using an acetone cotton ball and an isopropanol cotton ball, and the ITO glass is dried after being washed by isopropanol and then is treated by plasma for 5min for later use. The preparation of the device is completed by combining spin coating and vacuum evaporation technology.

(2) Preparation of hole injection layer and hole transport layer: firstly, a layer of PEDOT: PSS (Poly 3, 4-ethylenedioxythiophene): polystyrene sulfonate (purchased from Heraeus, Germany) with a thickness of 20nm is spin-coated on the surface of ITO as a hole injection layer, then Poly-HTL with a thickness of 50nm is spin-coated on the hole injection layer as a hole transport layer, and then the ITO glass with the hole injection layer and the hole transport layer is placed in a nitrogen-protected glove box and annealed at 200 ℃ for 30 minutes (to crosslink the Poly-HTL).

(3) Preparing a luminescent layer: dissolving the main material and the luminescent material in xylene according to the proportion of 97 wt% to 3 wt% (wt% is weight percentage concentration) to prepare a solution with the concentration of 2 wt%, and preparing a luminescent layer by using the prepared solution through a spin coating method, wherein the thickness of the luminescent layer is 50 nm.

(4) Preparing an electron transport layer, an electron injection layer and a metal electrode: the electron transmission layer, the electron injection layer and the metal electrode are prepared by adopting the evaporation process, and when the vacuum degree of a vacuum evaporation system reaches 5 multiplied by 10^-4Starting evaporation when the pressure is lower than Pa, and sequentially depositing an organic electron transport layer and a LiF electron injection layer on the luminescent layer by a vacuum evaporation process at a deposition rate of a Schen film thickness meterAnd a metallic Al electrode (see effect examples below for a specific device structure). Wherein the organic material has a deposition rate of

Deposition rate of LiF is

The deposition rate of Al is

The characteristics of the device such as current, voltage, brightness, light-emitting spectrum and the like are synchronously tested by a Photo Research PR 655 spectral scanning luminance meter and a Keithley K2400 digital source meter system. The performance test of the device is carried out at room temperature and in an ambient atmosphere. The External Quantum Efficiency (EQE) of the device is calculated from the current density, luminance and the electroluminescence spectrum in combination with the viewing function, in the case of a lambertian distribution of luminescence.

Effect example 2

In the organic electroluminescent device (structure shown in fig. 1) of effect example 2, PEDOT: PSS was used as a hole injection layer, Poly-HTL was used as a hole transport layer, H1-48 was used as a host material in the light emitting layer, BN-1 to BN-584 were used as doped light emitting materials (doping concentration was 3 wt%), TmPyPB was used as an electron transport material, LiF was used as an electron injection layer, and Al was used as a metal cathode, respectively. Effect examples the organic electroluminescent device structure was [ ITO/PEDOT: PSS (20nm)/Poly-HTL (50nm)// H1-48+3 wt% BN-n/TmPyPB (50nm)/LiF (1nm)/Al (100nm) ]. Wherein n is 1-618. Results of the examples are shown in table 3. The electroluminescent device effect implementation data listed in table 3 prove that the luminescent material provided by the present disclosure can be used for preparing a high-efficiency organic electroluminescent device, and the electroluminescent spectrum has a narrow band characteristic, and the half-peak width of the electroluminescent spectrum is less than 60 nm.

Table 3 BN-n (n ═ 1-584) main parameters of electroluminescence properties.

Effect example 3

In the organic electroluminescent device (structure shown in fig. 1) of effect example 3, PEDOT: PSS was used as a hole injection layer, Poly-HTL was used as a hole transport layer, a mixture of H1-33 and TRZ-1 was used as a host material in a light emitting layer (a weight mixing ratio of H1-33 to TRZ-1 was 1:1), BN-1 to BN-618 were used as doped light emitting materials (a doping concentration was 3 wt%), TmPyPB was used as an electron transport material, LiF was used as an electron injection layer, and Al was used as a metal cathode. Effect examples the organic electroluminescent device structure was [ ITO/PEDOT: PSS (20nm)/Poly-HTL (50nm)/H1-33: TRZ-1+3 wt% BN-n/TmPyPB (50nm)/LiF (1nm)/Al (100nm) ]. Wherein n is 1-584. Results of the examples are shown in table 4. The electroluminescent device effect implementation data listed in table 4 prove that the luminescent material provided by the present disclosure can be used for preparing a high-efficiency organic electroluminescent device, and the electroluminescent spectrum has narrow-band characteristics, and the half-peak width of the electroluminescent spectrum is less than 60 nm. Results of the examples are shown in table 4.

Table 4 BN-n (n ═ 1-584) main parameters of electroluminescence properties.

The above description is intended to be illustrative of the present invention and not to limit the scope of the invention, which is defined by the claims appended hereto.

Claims (20)

1. A boron-nitrogen compound having a structure represented by formula I or II,

R¹independently at each occurrence H, D (deuterium), fluorine, CN, C₁～C₂₀Alkyl radical, C₁～C₂₀Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^aSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl, substituted with one or more R^aSubstituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R^aA substituted diphenylamine group;

e is a single bond or

R¹¹And R²²Independently for each occurrence H, D (deuterium), C₁～C₆Alkyl or C₁～C₆An alkoxy group;

r is:

H、C₁～C₂₀alkyl radical, C₁～C₂₀Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^dSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl or substituted by one or more R^dSubstituted 5-to 18-membered heteroaryl;

R⁴、R⁵and R⁶Independently at each occurrence H, D (deuterium), fluorine, CN, C₁～C₂₀Alkyl radical, C₁～C₂₀Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^dSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl or substituted by one or more R^dSubstituted 5-to 18-membered heteroaryl;

R^aindependently at each occurrence, D (deuterium), fluoro, CN, C₁～C₁₂Alkyl radical, C₁～C₁₂Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^bSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl, substituted with one or more R^bSubstituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R^bA substituted diphenylamine group;

R^bindependently at each occurrence, D (deuterium), fluoro, CN, C₁～C₁₂Alkyl radical, C₁～C₁₂Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^cSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl, substituted with one or more R^cSubstituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R^cA substituted diphenylamine group;

R^cindependently at each occurrence, D (deuterium), fluoro, CN, C₁～C₁₂Alkyl radical, C₁～C₁₂Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals, substituted by one or more R^dSubstituted C₆～C₁₄Aryl, 5-to 18-membered heteroaryl, substituted with one or more R^dSubstituted 5-to 18-membered heteroaryl, diphenylamino, or substituted with one or more R^dA substituted diphenylamine group;

R^dindependently at each occurrence, D (deuterium), fluorine, C₁～C₁₂Alkyl radical, C₁～C₁₂Alkoxy radical, C₃-C₁₀Cycloalkyl radical, C₆～C₁₄Aryl radicals or by one or more R^eSubstituted C₆～C₁₄An aryl group;

R^eindependently at each occurrence, D (deuterium), fluorine, C₁～C₁₂Alkyl radical, C₁～C₁₂Alkoxy radical, C₃-C₁₀Cycloalkyl, or C₆～C₁₄An aryl group;

the above alkyl, alkoxy, cycloalkyl, aryl, heteroaryl groups are optionally substituted with one or more substituents selected from: halogen, -CN, C₁-C₁₂Alkyl radical, C₁-C₁₂Alkoxy radical, C₁-C₁₂Haloalkyl, C₂-C₆Alkenyl radical, C₃-C₁₀Cycloalkyl radical, C₆-C₁₄Aryl and 5-to 18-membered heteroaryl.

2. The boron-nitrogen compound of claim 1, whose antecedent molecular orbital has the following characteristics:

HOMO and LUMO are distributed in an alternating manner on ring atoms of ring c11, ring c12, ring c13, ring c14, ring B1 and one B and two N simultaneously connected to three of the rings in formula I, two N in formula I are distributed with HOMO, and B atom, ring m1 and ring ph1 are distributed with LUMO;

HOMO and LUMO are distributed in an alternating manner on the ring atoms of ring c21, ring c22, ring c23, ring c24, ring B2 and on one B and two N which are simultaneously connected to three of the rings in formula II, with the HOMO distributed on two N in formula II and the LUMO distributed on the B atom, ring m2 and ring ph 2.

3. The boron-nitrogen compound according to claim 1,

wherein E in formula I is a single bond or

Wherein in formula II

Is composed of

Wherein in formula I and formula II

Is any one of the following groups:

wherein in formula I and formula II

Is any one of the following groups:

4. the boron nitrogen compound of claim 1, wherein R¹¹And R²²Independently H or D (deuterium), R occurring in pairs¹¹And R²²At least one of which is hydrogen.

5. The boron nitrogen compound of claim 4, wherein R¹¹And R²²Are all hydrogen.

6. The boron nitrogen compound of claim 5, wherein R¹Independently at each occurrence H, F, CF₃、C₁～C₂₀Alkyl radical, C₁～C₂₀Alkoxy, cyclohexyl, adamantyl, phenyl, naphthyl, substituted with one or more R^aSubstituted phenyl, carbazolyl, substituted with one or more R^aSubstituted carbazolyl, diphenylamine, or substituted by one or more R^aSubstituted diphenylamine group, the R^aIs selected from C₁～C₆Alkyl radical, C₁-C₆Fluoroalkyl and C₁～C₆An alkoxy group.

7. The boron-nitrogen compound of claim 1, wherein,

e is a single bond or a benzene ring;

R¹independently for each occurrence is H, methyl, t-butyl, phenyl, 4-tolyl, 3, 5-xylyl, 4-t-butylphenyl, 3, 5-di-t-butylphenyl, diphenylamino, di (p-tolyl) amino, or di (p-t-butylphenyl) amino;

R¹¹and R²²Is H;

r is H or

R⁴And R⁵Identical and are tert-butyl, phenyl, 4-tolyl, 3, 5-xylyl, 4-tert-butylphenyl, 3, 5-di-tert-butylphenyl, 4-C₁～C₁₀Alkoxyphenyl, 3-C₁～C₁₀Alkoxyphenyl, or 3, 5-di-C₁～C₁₀An alkoxyphenyl group;

R⁶is H.

8. The boron nitrogen compound of claim 1, which is any one of the following compounds:

9. an organic electroluminescent composition comprising the boron nitrogen compound of any one of claims 1 to 8.

10. The organic electroluminescent composition according to claim 9, further comprising a host material having an electron and/or hole transport ability and having a triplet excited state energy higher than that of the boron nitrogen compound.

11. The organic electroluminescent composition of claim 10, wherein the host material comprises 99.7 to 70.0 wt% of the composition and the boron nitrogen compound comprises 0.3 to 30.0 wt% of the composition.

12. The organic electroluminescent composition according to claim 11, wherein the host material comprises one or more compounds represented by formulae (H-1) to (H-6),

wherein X₁、Y₁And Z₁Is CH or N, and X₁、Y₁And Z₁At most one of them is N;

wherein R is^1HAnd R^2HIndependently any of the following groups:

wherein X₂、Y₂And Z₂Is CH or N, and X₂、Y₂And Z₂At most one of them is N;

wherein R is^aHAnd R^bHIndependently H, C₁-C₂₀Alkyl radical, C₁-C₂₀Alkoxy radical, C₆-C₂₀Aryl radical, C₁-C₂₀Alkyl substituted C₆-C₂₀Aryl or C₁-C₂₀Alkoxy-substituted C₆-C₂₀And (4) an aryl group.

13. The organic electroluminescent composition according to claim 12, wherein the host material comprises 2 compounds of the formulae (H-1) to (H-6) and the weight ratio of the two compounds is 1:5 to 5: 1.

14. The organic electroluminescent composition of claim 12, wherein the host material is 1-2 of the compounds H1-1 to H1-427, and when the host material is two of the compounds H1-1 to H1-427, the weight ratio of the two compounds is 1:5 to 5:1,

15. the organic electroluminescent composition of claim 12, wherein the host material further comprises any one of 1,3, 5-triazine derivatives represented by formulas Trz1-A, Trz2-a and Trz 3-a; and the weight ratio of the 1,3, 5-triazine derivative shown by Trz1-A, Trz2-A or Trz3-A to the compounds shown by H-1, H-2, H-3, H-4, H-5 and H-6 is 1:5 to 5:1,

wherein R is^1a、R^1b、R^2a、R^2b、R^3aAnd R^3b1 or 2 of (a) are independently R^TzThe others are the same or different and independently hydrogen, deuterium, C₁-C₈Alkyl radical, C₁-C₈Alkoxy radical, C₆-C₁₈Aryl radical, C₁-C₈Alkyl substituted C₆-C₁₈Aryl or C₁-C₈Alkoxy-substituted C₆-C₁₈An aryl group; r^TzIs any one of substituent groups represented by the following formula:

16. the organic electroluminescent composition of claim 15, wherein the host material comprises any one of 1,3, 5-triazine derivatives represented by formulas TRZ-1 to TRZ-56 and any one of carbazole or carboline derivatives represented by formulas H1-1 to H1-427; in the main material, the weight ratio of the 1,3, 5-triazine derivative to the carbazole or carboline derivative is 1:5 to 5:1,

17. an organic electroluminescent device, at least one of the light-emitting layer, the electron-injecting layer, the electron-transporting layer, the hole-injecting layer of which comprises the boron nitrogen compound of any one of claims 1 to 8 or the organic electroluminescent composition of any one of claims 9 to 16.

18. The organic electroluminescent device according to claim 17, wherein a light-emitting layer thereof comprises the boron nitrogen compound or the organic electroluminescent composition.

19. The organic electroluminescent device of claim 17 or 18, which is used for producing an organic electroluminescent display or an illumination light source.

20. A method for producing the boron-nitrogen compound of claim 1, comprising the steps represented by the following reaction formulas (1) and (2):

in the reaction formula (1), a boron-nitrogen parent nucleus compound containing a carbazole skeleton is taken as a reactant, the reactant is dissolved in an organic solvent, heating and refluxing are carried out in the presence of a catalyst, and a hydrogen atom at a para position of a boron atom of a benzene ring is activated and substituted by boron ester;

introducing an electron-withdrawing group onto the boron-nitrogen skeleton by utilizing a Suzuki reaction in the reaction formula (2), wherein the introduced electron-withdrawing group is positioned at the para position of a B atom of a benzene ring B in the boron-nitrogen skeleton;

in equation (2), ArX is any one of the following three molecules:

wherein

X is Br or Cl;

R¹、R⁴、R⁵、R⁶、R¹¹、R²²r is as defined in claim 1.

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