ISOPHTHALONITRIL COMPOUNDS, LUMINESTENT MATERIAL AND LUMINESTENT ELEMENT WITH IT

Description

TECHNICAL FIELD

[0001] The present invention relates to an isophthalonitrile compound, a luminescent material and a luminescent element using the same. In further detail, the present invention relates to an isophthalonitrile compound in which the chirality based on a spiral structure is stable and luminescent characteristics are excellent, a luminescent material and a luminescent element using the same.

[0002] The present invention claims priority on the basis of Japanese Patent Application No. 2019-111304 filed in Japan on June 14, 2019.BACKGROUND OF THE INVENTION

[0003] Various luminescent materials used in an organic luminescent element have been proposed. For example, Patent Document 1 discloses a compound of formula (A).

[0004] In the formula (A), at least one of R 11< to R 15< is a cyano group, at least one of R 11< to R 15< is a group of formula (A1), and the remaining groups of R 11< to R 15< are a hydrogen atom or a substituent.

[0005] In the formula (A1), R 21< to R 28< are each independently a hydrogen atom or a substituent. R 25< and R 26< may form together a single bond, and R 27< and R 28< may form together a substituted or unsubstituted benzene ring with carbon atoms to which R 27< and R 28< are bonded.

[0006] Patent Document 2 discloses a compound of formula (B).

[0007] In the formula (B), R 11< to R 15< are each independently a hydrogen atom or a substituent. One of R 11< to R 15< is a cyano group. One to three of R 11< to R 15< are an aryl group Ar which may be substituted with an alkyl group or an aryl group (although a benzene ring constituting the former aryl group may be condensed with a ring which may contain an oxygen atom or a sulfur atom in addition to carbon atoms as a ring-constituting atom, the benzene ring is not condensed with a ring containing a hetero atom other than an oxygen atom or a sulfur atom as a ring-constituting atom). In the case where at least two of R 11< to R 15< are Ar, Ar may be identical to or different from each other. One to three of R 11< to R 15< are a donor group D (provided that a group corresponding to Ar is excluded). In the case where at least two of R 11< to R 15< are the group D, the group D may be identical to or different from each other.DOCUMENTS OF RELATED ARTPatent Documents

[0008] Patent Document 1: WO 2013 / 154064 A1 Patent Document 2: WO 2019 / 004254 A1 Patent Document 3: WO 2013 / 154064 describes luminescent compounds comprising a carbazole and indole substituted cyanobenzene derivative. Patent Document 4: CN 108,264,478 describes thermally activated delayed fluorescent compounds. Patent Document 5: WO 2015 / 199303 describes luminescent compounds comprising a substituted biphenyl moiety. Patent Document 6: US 2016 / 072076 describes luminescent compounds comprising benzene substituted with carbazole derivatives, bridged amines and an electron attracting group. Patent Document 7: JP 2019 / 006988 describes luminescent compounds that exhibit delayed fluorescence and comprise a dicyanobenzene derivative substituted with a donor and aryl group. SUMMARY OF THE INVENTIONPROBLEMS TO BE SOLVED BY THE INVENTION

[0009] The aims of the present invention are to provide an isophthalonitrile compound having excellent luminescent characteristics, a luminescent material and a luminescent element using the same.MEANS TO SOLVE THE PROBLEMS

[0010] As a result of intensive studies to solve the above problems, the present invention including the following aspects has been completed.

[0011] In a first aspect, there is provided a compound of formula (II-2) or formula (II-3):

[0012] In a second aspect, there is provided a luminescent material containing at least one selected from the compounds of formula (II-2) or formula (II-3) .

[0013] In a third aspect, there is provided a luminescent element containing the luminescent material of the second aspect.EFFECTS OF THE INVENTION

[0014] The isophthalonitrile compound according to the present invention is useful as a luminescent material. The luminescent element containing the luminescent material according to the present invention can realize excellent luminescent efficiency.BRIEF DESCRIPTION OF DRAWINGS

[0015] Fig. 1 is a drawing that indicates PL spectra of toluene solutions prepared in Example 4. Fig. 2 is a drawing that indicates voltage-current density characteristics of organic electroluminescent elements prepared in Example 5. Fig. 3 is a drawing that indicates current density-external quantum efficiency characteristics of organic electroluminescent elements prepared in Example 5. Fig. 4 is a drawing that indicates PL spectra of toluene solutions prepared in Example 9. Fig. 5 is a drawing that indicates voltage-current density characteristics of organic electroluminescent elements prepared in Example 10. Fig. 6 is a drawing that indicates current density-external quantum efficiency characteristics of organic electroluminescent elements prepared in Examples 6 to 8. EMBODIMENTS FOR CARRYING OUT THE INVENTION

[0016] The isophthalonitrile compound according to the present invention is a compound of formula (II-2) or formula (II-3):

[0017] The isophthalonitrile compound according to the present invention may be obtained by performing known synthesis reactions (such as a coupling reaction or substitution reaction) in combination. Purification of synthesized compounds may be carried out by purification using column chromatography, adsorption purification using silica gel, activated carbon, activated clay, or recrystallization or crystallization using a solvent. Compound identification may be performed by NMR analysis.

[0018] The compound according to the present invention may be obtained as follows, for example.(Embodiment 4) Synthesis of 2-(3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl)-4,6-diphenyl-isophthalonitrile (compound II-3): Ph-BiCz-PIN)

[0019]

[0020] t-BuOK, dehydrated DMF, and 9-phenyl-9H,9'H-3,3'-bicarbazole are put into a reaction container and then the mixture is stirred at room temperature to allow the reaction to proceed. Then, 5'-chloro-[1,1':3',1"-terphenyl]-4',6'-dicarbonitrile is added thereto and then refluxed, followed by pouring the resultant reaction solution into water, and then adding dichloromethane thereto to subject the mixture to extraction. The resultant organic layer is dried, filtered, concentrated, and purified to obtain the target compound.(Embodiment 5) Synthesis of 2-(3-(9-(4,6-diphenyl-isophthalonitril-2-yl)-9H-carbazol-3-yl)-9H-carbazol-9-yl)-4,6-diphenyl-isophthalonitrile (compound (II-2): BiCz-2PIN)

[0021]

[0022] t-BuOK, dehydrated DMF, and 9H,9'H-3,3'-bicarbazole are put into a reaction container, and then stirred at room temperature to allow the reaction to proceed. Then, 5'-chloro-[1,1':3',1"-terphenyl]-4',6'-dicarbonitrile is added thereto and then refluxed. The resultant reaction solution is poured into water, and dichloromethane is added thereto to subject the mixture to extraction. The resultant organic layer is dried, filtered, concentrated, and purified to obtain the target compound.

[0023] The isophthalonitrile compounds according to the present invention may be used as a luminescent material. The luminescent material according to the present invention can provide a luminescent element such as an organic photoluminescence element or an organic electroluminescence element. The isophthalonitrile compound according to the present invention has a function of assisting the emission of another luminescent material (host material), and therefore the compound may be doped with other luminescent materials.

[0024] The organic photoluminescent element according to the present invention is formed by providing a luminescent layer containing a luminescent material according to the present invention on a substrate. The luminescent layer may be formed by conducting a coating method such as spin coating, a printing method such as an ink-jet printing method, a vapor deposition method.

[0025] The organic electroluminescent element according to the present invention is formed by providing organic layers between an anode and a cathode. The term "organic layers" in the present invention refers to layers located between an anode and a cathode, the layers being substantially composed of organic substances, and the layers may include inorganic substances provided that the performance of the luminescent element according to the present invention is not impaired.

[0026] The structure of one embodiment of an organic electroluminescent element according to the present invention is composed of a substrate, an anode, a hole injection layer, a hole transport layer, an electron-blocking layer, a luminescent layer, a hole-blocking layer, an electron-transporting layer, and a cathode, which are provided in this order, and an electron injection layer may be further provided between the electron-transporting layer and the cathode. In the multilayered structure, it is possible to omit some of the organic layers, and, for example, an anode, a hole transport layer, a luminescent layer, an electron-transporting layer, an electron injection layer, and a cathode may be provided on a substrate in this order, alternatively, or an anode, a hole transport layer, a luminescent layer, an electron-transporting layer, and a cathode may be provided on a substrate in this order. The luminescent material according to the present invention may be doped not only in a light-luminescent layer, but also in a hole injection layer, a hole transport layer, an electron-blocking layer, a hole-blocking layer, an electron-transporting layer, or an electron injection layer.

[0027] The substrate is to be a support of the luminescent element, and a silicon plate, a quartz plate, a glass plate, a metal plate, a metal foil, a resin film, or a resin sheet is used. In particular, a glass plate, or a transparent plate of synthetic resin such as polyester, polymethacrylate, polycarbonate, or polysulfone is preferred. In the case where a synthetic resin substrate is used, it is necessary to pay attention to the gas barrier property. In the case where the gas barrier property of the substrate is too low, the luminescent element may be deteriorated by the outside air passing through the substrate. Therefore, it is preferable to ensure the gas barrier properties on either one or both sides of the synthetic resin substrate provided with a dense silicon oxide film.

[0028] An anode is provided on the substrate. A material having a high work function is generally used to form the anode. Examples of the anode material include: metals such as aluminum, gold, silver, nickel, palladium, and platinum; metal oxides such as indium oxide, tin oxide, ITO, zinc oxide, In 2 O 3 -ZnO, and IGZO; metal halides such as copper iodide, carbon black, and conductive polymers such as poly (3-methylthiophene), polypyrrole, and polyaniline. The anode is usually formed using a sputtering method, or a vacuum deposition method. In the case of fine particles of metal such as silver, fine particles of copper iodide, carbon black, conductive metal oxide fine particles or conductive polymer fine powders, the fine particles are dispersed in a suitable binder resin solution, and then applied on a substrate to form an anode. Furthermore, in the case of the conductive polymer, the conductive polymer may be subjected to electrolytic polymerization to form a thin film directly on a substrate, or may be applied on a substrate to form an anode.

[0029] The anode may also be formed by laminating at least two substances different from each other. The thickness of the anode varies depending on the required transparency. In the case where transparency is required, the transmittance of visible light is usually at least 60%, and preferably at least 80%. In this case, the thickness is usually from 10 to 1000 nm, and preferably from 10 to 200 nm. In the case where the anode may be opaque, the thickness of the anode may be approximately the same as that of the substrate. It is preferable that the sheet resistance of the anode be at least several hundred Ω / square.

[0030] In a hole injection layer which is provided as needed, a porphyrin compound such as copper phthalocyanine, a naphthalene diamine derivative, a star-burst type triphenylamine derivative, a trimer or a tetramer of triphenylamin such as an arylamine compound having a structure in which at least three triphenylamin structures are bonded with single bonds or divalent groups free from hetero atoms in a molecule thereof, an acceptor heterocyclic compound such as hexacyano azatriphenylene or a coating type polymer material may be used. These materials may be subjected to deposition or a known method such as a spin coating method or an inkjet method to form a thin film.

[0031] It is preferable that the hole transport material used in the hole transport layer provided as needed exhibit a high hole injection efficiency from an anode and realize transportation of the injected holes efficiently. For this purpose, a small ionization potential, high transparency to visible light, high hole mobility, excellent stability, and suppressed generation of impurities which become traps during manufacture or use are preferable. Besides the aforementioned general requirements, when application to a vehicle display is intended, it is further preferable that the heat resistance of the element be high. Therefore, a material having a value of 70°C or more as Tg is desirable.

[0032] In the hole transport layer which is provided as needed, a triazole derivative, an oxadiazole derivative, an imidazole derivative, a carbazole derivative, an indolocarbazole derivative, a polyarylalkane derivative, a pyrazoline derivative, a pyrazolone derivative, a phenylenediamine derivative, an arylamine derivative, an amino-substituted chalcone derivative, an oxazole derivative, a styryl anthracene derivative, a fluorenone derivatives, a hydrazone derivative, a stilbene derivative, a silazane derivative, an aniline copolymer, an electroconductive high-molecular oligomer may be used. More specifically, a compound having a m-carbazolylphenyl group, a benzidine derivative such as N, N'-diphenyl-N, N'-di(m-tolyl)-benzidine (hereinafter abbreviated as TPD), N, N'-diphenyl-N, N'-di(α-naphthyl)-benzidine (hereinafter abbreviated as NPD), N, N, N', N'- tetrabiphenylbenzidine, or 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (hereinafter abbreviated as TAPC), various triphenylamine trimers or tetramers, or a carbazole derivative may be used. One kind of these may be used, or at least two kinds thereof may be used in combination. The hole transport layer may be a film of a single layer structure, or may be a film of a laminated structure. Further, in the hole injection or transport layer, a coating type polymer material such as poly(3,4-ethylenedioxythiophene) (hereinafter abbreviated as PEDOT) / poly(styrenesulfonate) (hereinafter, abbreviated as PSS) may be used. These materials may be subjected to deposition or another known method such as a spin coating method or an inkjet method to form a thin film.

[0033] In the hole injection layer or the hole transport layer, materials in which tris-bromophenyl amine hexachloro antimony is P-doped to materials commonly used in the layer, or polymer compounds having the structure of the PD as the partial structure thereof may be used. As the hole injection or transport host material, a carbazole derivative such as CBP, TCTA, mCP may be used.

[0034] Compounds (hi1) to (hi7) which may be preferably used as hole injection materials are shown below.

[0035] Compounds (ht1) to (ht38) which may be preferably used as hole transport materials are shown below.

[0036] In an electron-blocking layer which is provided as needed, a compound having an electron blocking action, such as a carbazole derivative such as 4,4',4"-tri(N-carbazolyl) triphenylamine (hereinafter abbreviated as TCTA), 9,9-bis[4-(carbazol-9-yl) phenyl] fluorene, 1,3-bis(carbazol-9-yl) benzene (hereinafter abbreviated as mCP), or 2,2-bis(4-carbazol-9-yl-phenyl) adamantane (hereinafter, abbreviated as Ad-Cz), or a compound having a triphenylsilyl group and a triarylamine structure, such as 9-[4-(carbazol-9-yl) phenyl]-9-[4- (triphenylsilyl) phenyl]-9H-fluorene may be used. One of the materials may be used alone or at least two thereof may be used in combination. The electron-blocking layer may be a film having a single layer structure, or may be a film having a laminated structure. The materials may be subjected to deposition or another known method such as a spin coating method or an inkjet method to form a thin film.

[0037] Compounds (es1) to (es5) which may be preferably used as electron-blocking materials are shown below.

[0038] A luminescent layer is a layer configured to exhibit light-emission by generating excitons due to recombination of holes and electrons respectively injected from an anode or a cathode. The luminescent layer may be formed using a luminescent material according to the present invention alone, or may be formed by doping the luminescent material according to the present invention to a host material. Examples of the host material include: metal complexes of quinolinol derivatives such as tris (8-hydroxyquinoline) aluminum (hereinafter abbreviated as Alq3); anthracene derivatives, bisstyrylbenzene derivatives, pyrene derivatives, oxazole derivatives, polyparaphenylene vinylene derivatives, compounds having a bipyridyl group and an ortho-terphenyl structure, mCP, thiazole derivatives, benzimidazole derivatives, and polydialkylfluorene derivatives. The luminescent layer may contain a known dopant. Examples of the dopant include quinacridone, coumarin, rubrene, anthracene, perylene and derivatives thereof, benzopyran derivatives, rhodamine derivatives, and aminostyryl derivatives. A phosphorescent material such as a green phosphorescent material such as Ir(ppy)3, a blue phosphorescent material such as FIrpic, or FIr6, or a red phosphorescent material such as Btp2Ir (acac) may also be used. One of the materials may be used alone, or at least two thereof may be used in combination. The luminescent layer may be a film of a single layer structure, or may be a film of a laminated structure. The materials may be subjected to deposition or another known method such as a spin coating method or an inkjet method to form a thin-film.

[0039] In the case where a host material is used, the lower limit of the amount of the luminescent material according to the present invention which may be contained in the luminescent layer is preferably 0.1% by mass and more preferably 1% by mass, and the upper limit thereof is preferably 50% by mass, more preferably 20% by mass, and even more preferably 10% by mass.

[0040] Compounds (el1) to (el40) which may be preferably used as host materials in the luminescent layer are shown below.

[0041] In a hole-blocking layer which is provided as needed, a compound having a hole-blocking action, such as a compound having both a bipyridyl group and an ortho-terphenyl structure, a phenanthroline derivative such as bathocuproine (hereinafter abbreviated as BCP), a metal complex of quinolinol derivative such as aluminum (III) bis (2-methyl-8 quinolinate)-4-phenylphenolate (hereinafter, abbreviated as BAlq), various rare earth complexes, an oxazole derivative, a triazole derivative, or a triazine derivative may be used. These materials may also serve as materials of the electron-transporting layer. One of the materials may be used alone, or at least two thereof may be used in combination. The hole-blocking layer may be a film of a single layer structure, or may be a film of a laminated structure. The materials may be subjected to deposition or another known method such as a spin coating method or an inkjet method to form a thin-film.

[0042] Compounds (hs1) to (hs11) which may be preferably used as hole-blocking materials are shown below.

[0043] In addition to metal complexes of quinolinol derivatives such as Alq3 or BAlq, various other metal complexes, triazole derivatives, triazine derivatives, oxadiazole derivatives, thiadiazole derivatives, carbodiimide derivatives, quinoxaline derivatives, phenanthroline derivatives, or silole derivatives may be used in the electron-transporting layer which is provided as needed. One of the materials may be used alone, or at least two thereof may be used in combination. The electron-transporting layer may be a film of a single layer structure, or may be a film of a laminated structure. The materials may be subjected to deposition or another known method such as a spin coating method or an inkjet method to form a thin-film.

[0044] Although in an electron injection layer which is provided as needed, alkali metal salts such as lithium fluoride or cesium fluoride, alkaline earth metal salts such as magnesium fluoride, or metal oxides such as aluminum oxide may be used, the materials may not be contained in a preferred selection of an electron-transporting layer and a cathode.

[0045] In the electron injection layer or the electron-transporting layer, a material in which a metal such as cesium is n-doped to a material commonly used in the layer may be used.

[0046] Compounds (et1) to (et30) which are preferably used as electron-transporting materials are shown below.

[0047] Compounds (ei1) to (ei4) which may be preferably used as electron injection materials are shown below.

[0048] Compounds (st1) to (st5) which may be preferably used as stabilizing materials are shown below.

[0049] A material having a low work function is generally used in the cathode. Examples of the cathode material include sodium, an alloy of sodium and potassium, lithium, tin, magnesium, a mixture of magnesium and copper, a mixture of magnesium and aluminum, a mixture of magnesium and indium, a mixture of aluminum and aluminum oxide, indium, calcium, aluminum, silver, a mixture of lithium and aluminum, an alloy of magnesium and silver, an alloy of magnesium and indium, and an alloy of aluminum and magnesium. It is possible to obtain a transparent or semi-transparent cathode by using a transparent conductive material. The thickness of the cathode is usually 10 to 5000 nm, and preferably 50 to 200 nm. The sheet resistance of the cathode is preferably at least several hundred Ω / square.

[0050] For the purpose of protecting the cathode formed of a metal having a low work function, a layer of metal having a high work function and being stable against the atmosphere, such as aluminum, silver, nickel, chromium, gold, or platinum, is preferably laminated thereon, because the stability of the element is improved. A cathode interface layer may be provided between the cathode and an adjacent organic layer (such as an electron-transporting layer or an electron injection layer) to improve the contact therebetween. Examples of a material used in the cathode interface layer include aromatic diamine compounds, quinacridone compounds, naphthacene derivatives, organic silicon compounds, organic phosphorus compounds, compounds containing a N-phenyl carbazole skeleton, and N- vinylcarbazole polymer.

[0051] The luminescent element according to the present invention may also be applied in any of a single element, an element having a structure in which components thereof are arranged in an array configuration, and an element having a structure in which an anode and a cathode are arranged in the X-Y matrix configuration.

[0052] Effects of the embodiment according to the present invention will be shown below.

[0053] Organic photoluminescence elements and organic electroluminescent elements were prepared using the luminescent materials according to the present invention to evaluate the luminescent characteristics.

[0054] The luminescent characteristics were evaluated using SourceMeter (manufactured by Keithley Instruments: 2400 series), a spectroradiometer (manufactured by Konica Minolta Inc.: CS-2000), a fluorescence spectrophotometer (manufactured by JASCO Corporation: FP-8600), and a 100 mm Φ integrating sphere (manufactured by JASCO Corporation: ILF-835).EXAMPLESReference Example 1Synthesis of 2,5-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)isophthalonitrile (BCz-2IN-I)

[0055]

[0056] 2,5-Difluoroisophthalonitrile (0.25 g, 1.52 mmol), 3,6-di-t-butylcarbazole (0.85 g, 3.04 mmol), and 5 ml of dehydrated DMF were put into a 50 mL eggplant flask, and then cooled in an ice-water bath. 60% sodium hydride (0.14 g, 3.34 mmol) was added gradually, and then the mixture was stirred at room temperature for 4 hours. The resultant reaction solution was poured into ice-water, and the precipitated crystal was collected by filtration, and then washed with n-hexane / ethyl acetate = 9 / 1 to obtain 0.78 g of the target compound (at a yield of 75.0%). 1< H-NMR (400 MHz, CDCl 3 , δ): 8.36 (s, 2H), 8.18 (t, 4H), 7.58 (dd, 2H), 7.54 (dd, 2H), 7.51 (d, 2H), 7.15 (d, 2H), 1.50 (s, 18H), 1.49 (s, 18H)Reference Example 2Synthesis of 2,4-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)isophthalonitrile (abbreviated as BCz-2IN-II)

[0057]

[0058] 3,6-Di-t-butylcarbazole (2.92 g, 10.4 mmol) was put into a 200 mL three-necked flask in which the atmosphere was replaced with nitrogen, followed by dissolving in 30 mL of dehydrated tetrahydrofuran. Then, 60% sodium hydride (0.56 g, 14.0 mmol) was added thereto while conducting cooling with ice water, followed by stirring the mixture at room temperature for 0.5 hours. The mixture was cooled with ice water, and then 4,5-difluoroisophthalonitrile (0.57 g, 3.5 mmol) dissolved in 14 mL of dehydrated tetrahydrofuran was added thereto under nitrogen gas flow, followed by stirring the mixture at room temperature for 21 hours. The reaction solution was cooled with ice water, and then water and ethyl acetate were added thereto, followed by separating an organic layer. In addition, an aqueous layer was subjected to extraction with ethyl acetate twice, and the mixed organic layer was washed with saturated saline. The organic layer was dehydrated with magnesium sulfate, filtered and concentrated to obtain a crude product. The crude product was purified by silica gel column chromatography (eluent: n-hexane / benzene) to obtain a crude purified product. The crude purified product was washed with ethyl acetate and filtered, and then the solvent was distilled off to obtain 1.21 g of the target compound as a light yellowish-white solid at a yield of 51.0%. 1< H-NMR (400MHz, CDCl 3 , δ): 8.45 (s, 1H), 8.11 (d, J = 1.2 Hz, 4H), 7.89 (s, 1H), 7.50 (dd, J = 8.8 Hz, 1.6 Hz, 4H), 7.27 (d, J = 8.4 Hz, 4H), 1.45 (s, 36H)Reference Example 3Synthesis of 2-(3,6-di-tert-butyl-9H-carbazol-9-yl)-4,6-diphenyl-isophthalonitrile (BCz-2PIN)

[0059]

[0060] Potassium tert-butoxide (0.336 g, 3.00 mmol), dehydrated DMF (8 ml), and 3,6-di-t-butylcarbazole (0.838 g, 3.00 mmol) were put into a 50 mL schlenk flask, and then stirred at room temperature for 30 minutes. Then, 5'-chloro-[1,1':3',1"-terphenyl]-4',6'-dicarbonitrile (0.630 g, 2.00 mmol) was added thereto, and then refluxed for 24 hours. The reaction solution was poured into water, and dichloromethane was added thereto to subject the mixture to extraction. The resultant organic layer was dried with magnesium sulfate, filtered, and concentrated with a rotary evaporator. The resultant residue was purified by column chromatography (hexane / chloroform = 2 / 1) to obtain 0.645 g of the target compound (at a yield of 57.8%).

[0061] 1< H-NMR (400 MHz, CDCl 3 , δ): 8.18 (t, J = 0.9 Hz, 2H), 7.83 (s, 1H), 7.71-7.75 (m, 4H), 7.52-7.60 (m, 8H), 7.18 (d, J = 8.5 Hz, 2H), 1.46 (s, 18H).

[0062] 13< C NMR (125 MHz, CDCl 3 , δ): 151.12, 146.17, 144.246, 138.75, 136.19, 130.88, 130.2, 135.66, 134.14, 125.09, 124.59, 124.20, 123.37, 122.15, 117.63, 116.21, 115.51, 115.07, 112.35, 109.89, 109.10, 109.04, 35.09, 34.70, 34.42, 32.17, 31.88.Reference Example 4

[0063] In a glove box under a nitrogen atmosphere, toluene solutions of BCz-2PIN, BCz-2IN-I, and BCz-2IN-II (in an amount of 10 -5< M) were prepared as luminescent materials. PL spectra of these luminescent materials were measured. The results are shown in FIG 1.Reference Example 5

[0064] A HAT-CN (dipyrazino[2,3-F:2',3'-H]quinoxaline-2,3,6,7,10,11-hexacarbonitrile) layer having a thickness of 10 nm, a TAPC (di-[4-(N,N-ditolyl-amino)-phenyl]cyclohexane) layer having a thickness of 40 nm, a CCP (1,4-bis(carbazolyl)benzene) layer having a thickness of 10 nm, a mCP (1,3-bis(N-carbazolyl)benzene) layer having a thickness of 10 nm, a luminescent layer having a thickness of 20 nm, a PPF (2,8-bis(diphenylphosphine oxide)dibenzofuran) layer having a thickness of 10 nm, and a B3PyPBM (1,3-bis(3,5-dipyrid-3-yl-phenyl)benzene) layer having a thickness of 40 nm were laminated in this order by conducting vacuum evaporation (at 5.0 × 10 -4< Pa or less) on a glass substrate on which an anode made of indium tin oxide (ITO) was formed with a thickness of 50 nm. Then, an 8-hydroxy quinolinato lithium film having a thickness of 1 nm, and an aluminum film having a thickness of 100 nm were laminated in this order by a vacuum deposition method to form a cathode, and thus an organic electroluminescence element was obtained.

[0065] BCz-2PIN, BCz-IN-I, or BCz-IN-II was used as a doping material of the luminescent layer. The concentration of the doping material was set to be 20% by weight (in PPF).

[0066] The characteristics of the organic electroluminescent element were measured. The voltage - current density - luminescent intensity characteristics are shown in FIG. 2. In Fig, 2, black marks indicate current density, and white marks indicate luminescent intensity. The current density - external quantum efficiency characteristics are shown in FIG. 3. Other results are shown in Table 1. Table 1Compound in luminescent layerλ EL [nm]λ FWHM [nm]E FWHM [eV]V on [V]L max [cdm -2< ]EQE Max [%]EQE 100 cdm -2< [%]EQE 1000 cdm -2< [%]CEmax [cdA -1< ]PE max [1 m W -1< ]CIE (x, y)BCz-2PIN497830.414.2362921.120.316.054.538.4(0.20, 0.44)2BCz-2IN-I494780.393.4202321.017.77.843.037.1(0.18, 0.39)2BCz-2IN-II497790.43.4235721.717.48.144.621.7(0.19, 0.40) Example 6Synthesis of 2-(3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl)-4,6-diphenyl-isophthalonitrile (Ph-BiCz-PIN)

[0067]

[0068] t-BuOK (0.168 g, 1.50 mmol), dehydrated DMF (8 ml), and 9-phenyl-9H,9'H-3,3'-bicarbazole (0.612 g, 1.50 mmol) were put into a 50 mL schlenk flask, and then stirred at room temperature for 30 minutes. Then, 5'-chloro-[1,1':3',1"-terphenyl]-4',6'-dicarbonitrile (0.314 g, 1.00 mmol) was added thereto and then refluxed for 24 hours. The reaction solution was poured into water, and then dichloromethane was added thereto, followed by subjecting the mixture to extraction. The resultant organic layer was dried with magnesium sulfate, filtered, and concentrated by a rotary evaporator. The resultant residue was purified by column chromatography (hexane / chloroform = 8 / 1) to obtain 0.482 g of Ph-BiCz-PIN (at a yield of 70.2%). 1< H-NMR (400 MHz, CDCl 3 , δ): 8.47 (d, J = 1.8 Hz, 2H), 8.26 (dd, J = 8.5, 7.8 Hz, 2H), 7.87 (s, 1H), 7.84 (dd, J = 8.4, 1.9 Hz, 1H), 7.78 (dd, J = 8.5, 1.8 Hz, 1H), 7.75-7.73 (m, 4H), 7.65-7.62 (m, 4H), 7.60-7.31 (m, 15H)Example 7Synthesis of 2-(3-(9-(4,6-diphenylisophthalonitril-2-yl)-9H-carbazol-3-yl)-9H-carbazol-9-yl)-4,6-diphenyl-isophthalonitrile (BiCz-2PIN)

[0069]

[0070] t-BuOK (0.224 g, 2.00 mmol), dehydrated DMF (10 ml), and 9H,9'H-3,3'-bicarbazole (0.332 g, 1.00 mmol) were put into a 50 mL schlenk flask, and then stirred at room temperature for 30 minutes. Then, 5'-chloro-[1,1':3',1"-terphenyl]-4',6'-dicarbonitrile (0.628 g, 2.00 mmol) was added thereto and then refluxed for 24 hours. The reaction solution was poured into water, and then dichloromethane was added thereto, followed by subjecting the mixture to extraction. The resultant organic layer was dried with magnesium sulfate, filtered, and concentrated by a rotary evaporator. The resultant residue was purified by column chromatography (hexane / chloroform = 4 / 1) to obtain 0.350 g of BiCz-2PIN (at a yield of 39.0%). 1< H-NMR (400MHz, CDCl 3 , δ): 8.47 (d, J = 1.3 Hz, 2H), 8.26 (d, J = 7.8 Hz, 2H), 7.87 (s, 2H), 7.83 (dd, J = 8.4, 1.9 Hz, 2H), 7.75-7.72 (m, 8H), 7.61-7.50 (m, 14H), 7.43-7.35 (m, 4H), 7.28 (d, J = 8.0 Hz, 2H)Reference Example 8Synthesis of 2-(3,6-di-phenyl-9H-carbazol-9-yl)-4,6-diphenyl-isophthalonitrile (PCz-PIN)

[0071]

[0072] t-BuOK (0.672 g, 6.00 mmol), dehydrated DMF (16 ml), and 3,6-diphenylcarbazole (1.914 g, 6.00 mmol) were put into a 50 mL schlenk flask, and then stirred at room temperature for 30 minutes. Then, 5'-chloro-[1,1':3',1"-terphenyl]-4',6'-dicarbonitrile (0.942 g, 3.00 mmol) was added thereto and then refluxed for 24 hours. The reaction solution was poured into water, and then dichloromethane was added thereto, followed by subjecting the mixture to extraction. The resultant organic layer was dried with magnesium sulfate, filtered, and concentrated by a rotary evaporator. The resultant residue was purified by column chromatography (hexane / chloroform = 4 / 1) to obtain 0.956 g of PCz-PIN (at a yield of 53.4%). 1< H-NMR (400 MHz, CDCl 3 , δ): 8.41 (d, J = 1.3 Hz, 2H), 7.88 (s, 1H), 7.75-7.71 (m, 10H), 7.61-7.47 (m, 10H), 7.39-7.31 (m, 4H)Example 9

[0073] In a glove box under a nitrogen atmosphere, toluene solutions of Ph-BiCz-PIN, BiCz-2PIN, and PCz-PIN (in an amount of 10 -5< M) were prepared as luminescent materials. PL spectra of these luminescent materials were measured. The results are shown in FIG 4.Example 10

[0074] A HAT-CN layer having a thickness of 10 nm, a TAPC layer having a thickness of 40 nm, a CCP layer having a thickness of 10 nm, a mCP layer having a thickness of 10 nm, a luminescent layer having a thickness of 20 nm, a PPF layer having a thickness of 10 nm, and a B3PyPBM layer having a thickness of 40 nm were laminated in this order by conducting vacuum evaporation (at 5.0 × 10 -4< Pa or less) on a glass substrate on which an anode made of indium tin oxide (ITO) was formed with a thickness of 50 nm. Then, an 8-hydroxy quinolinato lithium film having a thickness of 1 nm, and an aluminum film having a thickness of 100 nm were laminated in this order by a vacuum deposition method to form a cathode, and thus an organic electroluminescence element was obtained.

[0075] Ph-BiCz-PIN, BiCz-2PIN, or PCz-PIN was used as a doping material of the luminescent layer. The concentration of the doping material was set to be 20% by weight (in PPF).

[0076] The characteristics of the organic electroluminescent element were measured. The voltage - current density - luminescent intensity characteristics are shown in FIG. 5. In Fig, 5, black marks indicate current density, and white marks indicate luminescent intensity. The current density - external quantum efficiency characteristics are shown in FIG. 6. Other results are shown in Table 2. Table 2Compound in luminescent layerλ EL [nm]λ FWHM [nm]V on [V]L max [cdm -2< ]EQE Max [%]EQE 100 cdm -2< [%]EQE 1000 cdm -2< [%]CE max [cdA -< 1]PE max [1 m W -1< ]CIE (x, y)PCz-PIN502846.01386218.717.715.351.225.3(0.23, 0.48)BiCz-2PIN533994.01827622.021.520.167.646.0(0.30, 0.55)Ph-BiCz-PIN5261023.41798018.718.116.360.240.4(0.35, 0.56)

[0077] Thus, a luminescent material containing the compound according to the present invention exhibited high luminescent characteristics.INDUSTRIAL APPLICABILITY

[0078] The isophthalonitrile compound according to the present invention is useful as a luminescent material. The luminescent element containing the luminescent material according to the present invention can achieve excellent luminescent efficiency.

Claims

1. A compound of formula (II-2) or formula (II-3):

2. A luminescent material comprising at least one selected from compounds of claim 1.

3. A luminescent element comprising a luminescent material of claim 2.