Phenanthroline derivatives and method for producing the same

Abstract

The object of the present invention is to obtain a phenanthroline derivative capable of suppressing a decrease in luminous efficiency even at a current density higher than conventional ones. [Solution] The present invention provides a phenanthroline derivative represented by a specific formula (1), wherein, when analyzed by high performance liquid chromatography, the absorption intensity area of ​​the phenanthroline derivative represented by the specific formula (A) and / or the specific formula (B) is 0.001% to 0.300% of the absorption intensity area of ​​the phenanthroline derivative represented by the specific formula (1).

Description

[Technical Field]

[0001] The present invention relates to a phenanthroline derivative and a method for producing the phenanthroline derivative. [Background technology]

[0002] Phenanthroline derivatives are useful compounds as light-emitting element materials for, for example, display elements, flat panel displays, backlights, lighting, interiors, signs, billboards, electrophotographic machines, optical signal generators, etc. Patent Document 1, for example, discloses an invention relating to such phenanthroline derivatives.

[0003] The invention of Patent Document 1 is an invention of a phenanthroline derivative in which the total content of by-products having peaks at retention times between 13 and 25 minutes when analyzed by high performance liquid chromatography (hereinafter referred to as HPLC) is 0.045% or less, as calculated from the absorption intensity area ratio, and the invention is an invention in which the generation of impurities consisting of compounds in which the linking group connecting two phenanthroline derivatives is a linking group formed by bonding 2 to 5 phenylene groups is suppressed.

[0004] The invention was to produce a phenanthroline derivative by a production method that includes, in this order, consecutively carrying out (Step 1A) to (Step 4A), (Step 5A) a step of oxidizing the reaction product of Step 4A to obtain a crude product of the phenanthroline derivative, and (Step 6A) a step of recrystallizing and further sublimating the crude product of the phenanthroline derivative of Step 5A. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-45495 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the phenanthroline derivative of the invention of Patent Document 1 has the effect of providing a light-emitting device with low driving voltage and excellent durability, but in the case of a light-emitting device driven by a passive matrix, for example, the current is 200 mA / cm 2 In some cases, it is necessary to drive the device at a high current density up to about 1000 psig, and in order to repeatedly drive the device at such high current densities, it is necessary to further improve durability.

[0007] Furthermore, the method for producing a phenanthroline derivative disclosed in Patent Document 1 includes a step (Step 5A) in which the reaction product of Step 4A is oxidized to obtain a crude product of the phenanthroline derivative. However, there is a possibility that the reaction in Step 4A may not be completed for some reason, leaving a portion of the lithiation reaction product of Step 3A remaining. This may result in the risk of the remaining lithiation reaction product being oxidized to generate new impurities. Therefore, in order to remove the new impurities and obtain a highly pure phenanthroline derivative, the crude product of the phenanthroline derivative must be recrystallized and further sublimated (Step 6A), which must be repeated many times.

[0008] The present invention aims to obtain a phenanthroline derivative that can suppress the generation of new impurities so that the recrystallization and sublimation steps (Step 6A) do not need to be repeated many times, and that can suppress the decrease in luminous efficiency even at a current density higher than conventional ones. [Means for solving the problem]

[0009] That is, the present invention is as follows. [1] A phenanthroline derivative whose main component is a phenanthroline derivative represented by the following formula (1), wherein when analyzed by high performance liquid chromatography (HPLC), the absorption intensity area of ​​the phenanthroline derivative represented by the following formula (A) and / or the following formula (B) is 0.001% to 0.300% of the absorption intensity area of ​​the phenanthroline derivative represented by the following formula (1).

[0010] [ka]

[0011] (X and Y each independently represent a substituted or unsubstituted aryl group.)

[0012] [ka]

[0013] (X represents a substituted or unsubstituted aryl group; R represents a hydrogen atom, a halogen atom, a cyano group, or a substituted or unsubstituted alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, or alkoxy group having 1 to 9 carbon atoms; and Z represents a substituted aryl group. However, the phenanthroline derivative represented by formula (B) has a structure different from that of the phenanthroline derivative represented by formula (1).) [2] The phenanthroline derivative according to [1], wherein the phenanthroline derivative represented by the formula (1) is a phenanthroline derivative represented by the formula (3) described below. [3] The phenanthroline derivative according to [1] or [2], wherein the phenanthroline derivative represented by the formula (A) and / or the formula (B) is one or more compounds selected from the group consisting of the formula (4) described later, the formula (5) described later, and the formula (14) described later. [4] The phenanthroline derivative according to [3], wherein the phenanthroline derivative represented by the formula (A) and / or the formula (B) is two or more compounds selected from the group consisting of the formula (4), the formula (5), and the formula (14). [5] The phenanthroline derivative according to [4], wherein the phenanthroline derivative represented by the formula (A) and / or the formula (B) includes at least both the compound represented by the formula (5) and the compound represented by the formula (14). [6] The phenanthroline derivative according to any one of [1] to [5], wherein the absorption intensity area of ​​the phenanthroline derivative represented by the formula (A) and / or the formula (B) is 0.001% to 0.030% of the absorption intensity area of ​​the phenanthroline derivative represented by the formula (1) when analyzed by the high performance liquid chromatography. [7] The phenanthroline derivative according to any one of [1] to [6], wherein the conditions for the analysis by high performance liquid chromatography are as follows: Equipment: Shimadzu Corporation Nexera lite system (LC-40 series) Detector: Shimadzu Corporation photodiode array detector (SPD-M40) Column: High-purity spherical silica gel particle octyl-group chemically bonded packing reversed-phase column Theoretical plate number: 105,000±10,000(N / m) Column temperature: 45℃ Flow rate: 1.0mL / min Injection volume: 10μL Measurement sample concentration: 5.0 mg / 40 ml of tetrahydrofuran Mobile phase: Solution A: 0.1% by weight phosphoric acid aqueous solution, Solution B: Acetonitrile / tetrahydrofuran mixture (weight ratio 80 / 20) Flow conditions: Initially, the volume ratio of solution A to solution B was 55 / 45, and after a retention time of 25 minutes, only solution B was used, with a linear gradient for the first 25 minutes. Analysis software: Shimadzu Corporation Lab Solutions Measurement wavelength: 254nm Phenanthroline derivative detection area: 6,000,000 or more Minimum compound detection area: 60 Width(W):1sec Slope(S):1,000μV / min Drift(D):300μV / min T.DBL(T): 1,000 minutes [8] A method for producing a phenanthroline derivative, comprising the steps of (step 1) reacting a 1,3-dihalogenated aromatic compound with an organolithium reagent, (step 2) reacting the lithiation reaction product of step 1 with a phenanthroline derivative of formula (6) described below, (step 3) reacting the reaction product of step 2 with an organolithium reagent, (step 4) reacting the lithiation reaction product of step 3 with a phenanthroline derivative of formula (7) described below and a phenanthroline derivative of formula (8) described below, (step 5) oxidizing the reaction product of step 4 to obtain a crude product of the phenanthroline derivative, and (step 6) recrystallizing the crude product of the phenanthroline derivative of step 5, followed by sublimation. [9] A light-emitting element comprising the phenanthroline derivative according to any one of [1] to [7].

[10] A display device comprising the light-emitting element according to [9]. [Effects of the Invention]

[0014] The phenanthroline derivative of the present invention contains a trace amount of the phenanthroline derivative represented by formula (A) and / or formula (B), and therefore has the effect of suppressing a decrease in luminous efficiency even at a current density higher than conventional ones. Furthermore, the method for producing the phenanthroline derivative of the present invention can eliminate the steps of recrystallization and sublimation of the crude product, thereby significantly improving productivity. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is an absorption spectrum obtained by HPLC analysis of the phenanthroline derivative obtained in Example 1. [Figure 2] 1 is a mass spectrum of the detection peak (511.19 [M+H]+) of the compound in mass spectrometry of the phenanthroline derivative represented by formula (A) among the absorption spectra obtained by HPLC analysis of the phenanthroline derivative obtained in Example 1. [Figure 3]This is a mass spectrum of the detection peak (567.25 [M+H]+) of the compound in mass spectrometry of the phenanthroline derivative represented by formula (B), among the absorption spectra obtained by HPLC analysis of the phenanthroline derivative obtained in Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described in detail below. The phenanthroline derivative of the present invention has a compound represented by the following formula (1) as a main component. X and Y below each independently represent a substituted or unsubstituted aryl group. X and Y below may be the same or different. The aryl group is an aromatic hydrocarbon group obtained by removing one hydrogen atom on an aromatic ring from an aromatic hydrocarbon compound, and may be either a single ring or a condensed ring. In the present invention, even if a compound having a structure other than that represented by the above formula (1) is included, it is still referred to as a phenanthroline derivative.

[0017] [ka]

[0018] Examples of the aryl group include a phenyl group, a naphthyl group, a fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthryl group, an anthracenyl group, a benzophenanthryl group, a benzanthracenyl group, a chrysenyl group, a pyrenyl group, a fluoranthenyl group, a triphenylenyl group, a benzofluoranthenyl group, a dibenzanthracenyl group, a perylenyl group, and a helicenyl group.

[0019] The number of ring carbon atoms in the aryl group is not particularly limited, but is preferably in the range of 6 to 40, more preferably 6 to 11. In addition, in a phenyl group, when two adjacent carbon atoms in the phenyl group each have a substituent, these substituents may form a ring structure. Depending on the structure, the resulting group may fall into one or more of the following categories: a "substituted phenyl group," an "aryl group having a structure in which two or more rings are fused," and a "heteroaryl group having a structure in which two or more rings are fused."

[0020] Among the above aryl groups, phenyl, naphthyl, fluorenyl, phenanthryl, anthracenyl, pyrenyl, fluoranthenyl, and triphenylenyl are preferred. Furthermore, among these, a compound represented by the following formula (3), in which both X and Y are phenyl groups, is preferred in terms of low-voltage operation, durability, and the like.

[0021] [ka]

[0022] Furthermore, the phenanthroline derivatives used as organic light-emitting device materials and the like, which are the main component represented by the above formula (1), may be contaminated with metal ions, halogen-containing compounds, by-products, solvents, etc. derived from the raw materials. From the viewpoints of suppressing bumping during sublimation purification and further improving the properties of light-emitting devices such as low-voltage operation and durability, the higher the purity of the phenanthroline derivatives as the main component represented by the above formula (1), the more preferable it is.

[0023] However, some by-products, such as dopant materials, when contained in minute amounts, may exhibit more advantageous properties than phenanthroline derivatives containing only the main component. Therefore, in the present invention, such useful compounds were identified, and the amount of the compounds was calculated from the absorption intensity area ratio.

[0024] Specifically, the phenanthroline derivative of the present invention is characterized in that the absorption intensity area of ​​the phenanthroline derivative represented by formula (A) and / or formula (B) is 0.001% to 0.300% of the absorption intensity area of ​​the phenanthroline derivative represented by formula (1). When a minute amount of the phenanthroline derivative represented by formula (A) and / or formula (B) is contained, such as in a dopant material, it is believed to exhibit more advantageous properties than a phenanthroline derivative consisting solely of the main component, and to improve durability when driven at high current density.

[0025] If the absorption intensity area of ​​the phenanthroline derivative represented by formula (A) and / or formula (B) exceeds 0.300% of the absorption intensity area of ​​the phenanthroline derivative represented by formula (1), it is believed that this will adversely affect the electrical properties of the phenanthroline derivative represented by formula (1), and the durability will actually decrease. Also, if the absorption intensity area of ​​the phenanthroline derivative represented by formula (A) and / or formula (B) is less than 0.001% of the absorption intensity area of ​​the phenanthroline derivative represented by formula (1), it is believed that the effects of the present invention will be difficult to achieve, and sufficient durability will not be obtained.

[0026] This durability improvement effect is particularly pronounced when the light-emitting device is driven at high temperatures. This is thought to be due to the partial crystallization of the phenanthroline derivative when the light-emitting device is driven at high temperatures. However, the inclusion of the phenanthroline derivative represented by formula (A) and / or formula (B) reduces the crystallinity, making it less likely for the crystals that cause degradation to form. It has also been revealed that a further advantage of reducing the crystallinity is the suppression of voltage rise after continuous driving at high temperatures.

[0027] Here, the ratio of the absorption intensity area of ​​the phenanthroline derivative represented by formula (A) and / or formula (B) to the absorption intensity area of ​​the phenanthroline derivative represented by formula (1) is calculated by rounding off to three decimal places. Furthermore, when a plurality of phenanthroline derivatives represented by formula (A) and / or formula (B) are contained, the ratio of the total absorption intensity area of ​​the phenanthroline derivatives represented by formula (A) and / or formula (B) to the absorption intensity area of ​​the phenanthroline derivative represented by formula (1) is calculated.

[0028] <High-Performance Liquid Chromatography (HPLC) Analysis> An example of the conditions for HPLC analysis of the phenanthroline derivative of the present invention is described below. Equipment: Shimadzu Corporation Nexera lite system (LC-40 series) Detector: Shimadzu Corporation photodiode array detector (SPD-M40) Column: High-purity spherical silica gel particle octyl-group chemically bonded packing reversed-phase column Theoretical plate number: 105,000±10,000(N / m) Column temperature: 45℃ Flow rate: 1.0mL / min Injection volume: 10μL Measurement sample concentration: 5.0 mg / 40 ml of tetrahydrofuran Mobile phase: Solution A: 0.1% by weight phosphoric acid aqueous solution, Solution B: Acetonitrile / tetrahydrofuran mixture (weight ratio 80 / 20) Flow conditions: Initially, the volume ratio of solution A to solution B was 55 / 45, and after a retention time of 25 minutes, only solution B was used, with a linear gradient for the first 25 minutes. Analysis software: Shimadzu Corporation Lab Solutions Measurement wavelength: 254nm Phenanthroline derivative detection area: 6,000,000 or more Minimum compound detection area: 60 Width(W):1sec Slope(S):1,000μV / min Drift(D):300μV / min T.DBL(T): 1,000 min.

[0029] The above-mentioned equipment and detectors used in HPLC analysis have the advantage of a wide dynamic range when simultaneously analyzing multiple compounds with significantly different amounts, such as main components and by-products, making it possible to simultaneously analyze main components and trace by-products.

[0030] The above column types are reversed-phase columns compatible with analytical validation, in which the polar groups on the packing surface have been deactivated to the maximum extent possible. By selecting a column using a reversed-phase packing material with short hydrophobic groups, in which octyl groups are chemically bonded to high-purity spherical silica gel particles, the highly hydrophobic phenanthroline derivatives of the present invention can be separated and eluted in a relatively short time. Furthermore, reversed-phase columns compatible with analytical validation, in which the polar groups on the packing surface have been deactivated to the maximum extent possible, are suitable for separating and eluting aromatic organic compounds.

[0031] Furthermore, by selecting a column size that provides a theoretical plate number, which is an indicator of the column packing state, of 105,000±10,000 (N / m), trace amounts of compounds can be detected with high accuracy. An example of such a column is Mightysil RP-8GP (manufactured by Kanto Chemical Co., Inc.). The column size should preferably be 250 mm long and 4.6 mm inner diameter (5 μm particle diameter). The column temperature, flow rate, injection volume, and measurement sample concentration used in the analysis are all general-purpose conditions.

[0032] The mobile phases were prepared as follows: Solution A, a 0.1 wt% aqueous solution of phosphoric acid, and Solution B, an acetonitrile / tetrahydrofuran mixture (weight ratio 80 / 20). The volume ratio of Solution A / Solution B was initially 55 / 45, and after a retention time of 25 minutes, only Solution B was used. During this time (the first 25 minutes), the solution was pumped under linear gradient elution conditions.

[0033] A gradient is a development condition in which the composition of mobile phase solution B increases over time, while a linear gradient is a flow condition in which the mobile phase solution B increases at a constant rate in proportion to the retention time. By selecting such linear gradient flow conditions, it is possible to suppress the overlap of multiple peaks and make the peaks of by-products with long retention times sharp and easy to detect.

[0034] Under these conditions, the content of each component eluted from the column can be analyzed qualitatively and quantitatively from the ultraviolet absorption spectrum at a measurement wavelength of 254 nm. Specifically, using Shimadzu Corporation's Lab Solutions analysis software, the conditions for uniformly detecting small peaks were as follows: Width (W), which represents the minimum detectable peak width, was 1 second; Slope (S), which represents the slope used to distinguish the peak start and end points and represents peak detection sensitivity, was 300 μV / min; Drift (D), which represents the slope required for complete peak separation (baseline separation), was 300 μV / min; and the specified time T.DBL (T), over which the slope and drift values ​​are changed, was 1,000 minutes.

[0035] When HPLC analysis is performed under the above conditions, a peak of the phenanthroline derivative having the structure represented by formula (1) is detected at a retention time of 12 to 13 minutes, and the detection area of ​​the phenanthroline derivative is 6,000,000 or more. The peak of the compound is detected with an area of ​​0.001% or more of that as the minimum detection area of ​​the compound. As an example, Figure 1 shows the absorption spectrum obtained by HPLC analysis of the phenanthroline derivative of the present invention obtained in Example 1 described later.

[0036] Furthermore, when HPLC analysis is carried out under the above conditions, the peak of the phenanthroline derivative represented by formula (A) and / or formula (B) is detected at a retention time of 7 to 8 minutes.

[0037] [ka]

[0038] The phenanthroline derivative represented by the above formula (A) has a structure in which Y in the phenanthroline derivative represented by the above formula (1) is substituted with R (R represents any one of a hydrogen atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 9 carbon atoms, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, and an alkoxy group).

[0039] The alkyl group refers to a saturated aliphatic hydrocarbon group such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, or pentyl. The cycloalkyl group refers to a saturated alicyclic hydrocarbon group such as cyclopropyl, cyclohexyl, norbornyl, or adamantyl. The alkenyl group refers to an unsaturated aliphatic hydrocarbon group containing a double bond such as vinyl or butadienyl.

[0040] The cycloalkenyl group refers to an unsaturated alicyclic hydrocarbon group containing a double bond, such as a cyclopentenyl group, a cyclopentadienyl group, or a cyclohexenyl group. The alkynyl group refers to an unsaturated aliphatic hydrocarbon group containing a triple bond, such as an ethynyl group. The alkoxy group refers to a functional group in which an aliphatic hydrocarbon group is bonded via an ether bond, such as a methoxy group, an ethoxy group, or a propoxy group.

[0041] Among the compounds represented by the above formula (A), those in which R is a hydrogen atom, a halogen atom, a cyano group, or a substituted or unsubstituted alkyl group having 1 to 9 carbon atoms are preferred, as they are more likely to smoothly react with the lithiation reaction product remaining in step 4. More preferred compounds include compounds represented by the following formula (4) and formula (5).

[0042] The phenanthroline derivative represented by the formula (B) is a compound different from the phenanthroline derivative represented by the formula (1), which is the main component, among the phenanthroline derivatives represented by the formula (1). Among the compounds represented by the formula (B), the compound represented by the formula (14) is preferred.

[0043] [ka]

[0044] The presence of the phenanthroline derivatives represented by the above formula (A) and / or formula (B) in an extremely small amount relative to the phenanthroline derivative represented by the above formula (1) exhibits the property of suppressing the decrease in luminous efficiency under high current density. Although the mechanism is not clear, it is speculated that this is because the deactivation of active species of excitons, particularly triplet excitons, generated by operation under high current density is suppressed, allowing these excitons to be continuously used in the luminescence transition process.

[0045] The phenanthroline derivative represented by the formula (1) can be obtained, for example, by reacting a 1,3-dihalogenated aromatic compound with an organolithium reagent to perform dilithiation, then allowing a phenanthroline derivative represented by the following formula (6) to act on the compound, then reacting the reaction product with an organolithium reagent, then reacting the reaction product with a phenanthroline derivative represented by the following formula (7), and then oxidizing the reaction product.

[0046] The phenanthroline derivative represented by the formula (A) can be obtained by reacting a phenanthroline derivative represented by the formula (8) below instead of the phenanthroline derivative represented by the formula (7) below. The phenanthroline derivative of the present invention can be obtained by weighing a very small amount of the obtained phenanthroline derivative represented by the formula (A) above and mixing it with the phenanthroline derivative represented by the formula (1) above.

[0047] [ka]

[0048] Alternatively, the following production method can be mentioned, in which the phenanthroline derivative of the formula (1) and the phenanthroline derivative of the formula (A) are synthesized continuously and simultaneously in a series of steps. The production method includes the steps of: (Step 1) reacting a 1,3-dihalogenated aromatic compound with an organolithium reagent; (Step 2) reacting the lithiation reaction product of Step 1 with the phenanthroline derivative of formula (6); (Step 3) reacting the reaction product of Step 2 with an organolithium reagent; and (Step 4) reacting the lithiation reaction product of Step 3 with the phenanthroline derivative of formula (7) and the phenanthroline derivative of formula (8).

[0049] In this step, even if the reaction of the lithiation reaction product of step 3 with the phenanthroline derivative of formula (7) in (step 4) does not complete for some reason, and the lithiation reaction product of step 3 remains, the phenanthroline derivative of formula (8) reacts with the remaining lithiation reaction product, and therefore, almost no unreacted lithiation reaction product of step 3 remains in the subsequent steps, and the generation of new impurities is suppressed.

[0050] As a result, in the subsequent step (Step 5) of oxidizing the reaction product of Step 4 to obtain a crude product of the phenanthroline derivative, almost no by-products are produced other than the phenanthroline derivative of Formula (1) and a small amount of the phenanthroline derivative of Formula (A). Conventionally, in order to remove impurities, the crude product of the phenanthroline derivative of Step 5 in Step 6 has had to be recrystallized and sublimated many times, but this method can significantly reduce the number of such steps, thereby improving the productivity of the phenanthroline derivative of the present invention.

[0051] In addition, by appropriately controlling the step (Step 5), a product of the phenanthroline derivative of formula (1) and a moderately small amount of the phenanthroline derivative of formula (A) can be obtained, and as a result, a phenanthroline derivative with excellent properties that suppresses the decrease in luminous efficiency at high current densities compared to the phenanthroline derivative of formula (1) alone can be obtained.

[0052] All of these steps can be carried out batchwise, but to further improve productivity, steps 1 to 4 can be carried out using a flow synthesis process (hereinafter referred to as flow). That is, in this process, raw materials are sent from a reservoir into a flow channel using a liquid delivery pump, mixed in a mixer, and reacted in a thin tubular reaction vessel (reactor) while flowing through the flow channel, and the compound produced is then discharged from the flow channel.

[0053] In a flow reactor, the diffusion rate and reaction rate of the raw materials depend on the size of the reaction vessel, and because the space for mixing the raw materials is smaller than in a batch reactor, the raw materials are mixed accurately and quickly at a mixing ratio determined by the flow rate. This prevents a decrease in reaction rate and further suppresses side reactions. In addition, a flow reactor makes it easier to maintain a uniform temperature throughout the reaction system, and can also suppress the generation of by-products due to side reactions caused by localized temperature increases.

[0054] Examples of the pump include a plunger pump and a diaphragm pump. Examples of the shape of the mixer include a T-shape and a Y-shape. The flow path diameter (inner diameter) of the mixer is preferably 100 μm to 3 mm.

[0055] Each raw material will be described in detail below. Examples of the 1,3-dihalogenated benzene used in (Step 1) include 1,3-dibromobenzene, 1,3-diiodobenzene, and 1-bromo-3-iodobenzene. Two or more of these may be used. Among these, 1,3-dibromobenzene is preferred.

[0056] Examples of organolithium reagents include n-butyllithium, sec-butyllithium, and tert-butyllithium. Two or more of these may be used. Among these, n-butyllithium is preferred.

[0057] These are preferably reacted in a solution state, and examples of the solvent include saturated hydrocarbons having 5 to 8 carbon atoms, such as pentane, hexane, heptane, octane, and cyclohexane, and ethers, such as tert-butyl methyl ether, cyclopentyl methyl ether, dimethyl ether, diethyl ether, dibutyl ether, 1,4-dioxane, and tetrahydrofuran. Two or more of these may be used. The solution concentration of each raw material is preferably 5.0 M or less, and more preferably 2.0 M or less.

[0058] It is preferable to use 0.8 to 1.1 equivalents of the organolithium reagent relative to 1,3-dihalogenated benzene. The flow rate (ml / min) of each raw material is preferably 1 ml / min or more, more preferably 4 ml / min or more. The reaction temperature is preferably -20 to 40°C. The residence time (reaction time) in (Step 1) is preferably 0.1 to 3 seconds, taking into account the time required for the halogen-lithium exchange reaction and the stabilization time of the lithiation reaction product. From the viewpoint of further reducing the above-mentioned by-products, 2.5 seconds or less is more preferable.

[0059] Examples of the phenanthroline derivative of formula (6) used in (Step 2) include 2-phenyl-1,10-phenanthroline, 2-(4-hydroxyphenyl)-1,10-phenanthroline, 2-(4-methoxyphenyl)-1,10-phenanthroline, 2-(4-tert-butyl)-phenyl-1,10-phenanthroline, 2-(4-tert-butyl)-phenyl-1,10-phenanthroline, and 2-(3,5-di-tert-butyl-4-methoxyphenyl)-1,10-phenanthroline. It is preferable to use 0.8 to 1.1 equivalents of this compound. Furthermore, the residence time in (Step 2) is preferably 4 to 6 seconds, taking into account the time required for the reaction of phenanthroline. The reaction temperature is preferably −20 to 40° C.

[0060] A preferred embodiment of (Step 3) is the same as (Step 1). Examples of the phenanthroline derivative of formula (7) used in (Step 4) include the same compound as formula (6) used in (Step 2) above. A preferred embodiment of (Step 4) when using the same raw material as in (Step 2) is the same as (Step 2).

[0061] Examples of the phenanthroline derivative of formula (8) used in (Step 4) include 1,10-phenanthroline, 2-methyl-1,10-phenanthroline, 2-ethyl-1,10-phenanthroline, 2-isopropyl-1,10-phenanthroline, 2-butyl-1,10-phenanthroline, 2-tert-butyl-1,10-phenanthroline, and 2-cyclohexyl-1,10-phenanthroline.

[0062] Examples of the oxidizing agent used in the oxidation reaction in (Step 3) include manganese dioxide, nitrobenzene, chloranil, DDQ, air, oxygen, and water. Two or more of these may be used. The amount of the oxidizing agent used can be appropriately selected depending on the oxidizing agent used, and 1 to 10 equivalents relative to the compound of formula (7) are preferred.

[0063] Examples of solvents used in the oxidation step include aromatic hydrocarbon solvents such as benzene, toluene, xylene, and nitrobenzene; halogenated hydrocarbon solvents such as dichloromethane and chloroform; ether solvents such as diethyl ether, tert-butyl methyl ether, cyclopentyl methyl ether, tetrahydrofuran, 1,4-dioxane, and dimethoxyethane; and N,N-dimethylformamide and N,N'-dimethylimidazolidinone (DMI). Two or more of these may be used. The reaction temperature can be appropriately selected depending on the oxidizing agent used, and is preferably −20 to 60°C. The reaction time is preferably about 10 minutes to 24 hours.

[0064] Examples of solvents used for recrystallization in (Step 6) include toluene, hexane, tetrahydrofuran, dioxane, dimethoxyethane, ethanol, methanol, acetone, methyl ethyl ketone, ethyl acetate, n-butyl lactone, nitrobenzene, dichloromethane, chloroform, dimethyl sulfoxide, dimethylformamide, 1-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, pyridine, triethylamine, etc. Two or more of these may be used.

[0065] The heating temperature and crystallization temperature for recrystallization can be appropriately selected depending on the solvent used, and are preferably 0 to 130° C. The sublimation temperature is preferably 400° C. or less, and the degree of vacuum in the sublimation purification is 1.0×10 -3 Preferably, the absorption intensity area is not more than Pa. As described above, by the method for producing a phenanthroline derivative of the present invention, it is possible to easily obtain a phenanthroline derivative represented by formula (A) and / or formula (B) having an absorption intensity area of ​​0.001% to 0.030% of the absorption intensity area of ​​the phenanthroline derivative represented by formula (1). [Example]

[0066] The evaluations in each of the examples and comparative examples were carried out by the following methods.

[0067] (1) Analysis by HPLC 4.0 mg of the phenanthroline derivative obtained in each Example and Comparative Example was weighed into a glass container and dissolved in 40 ml of tetrahydrofuran. 1 ml of the resulting solution was transferred to an HPLC vial to prepare an HPLC measurement sample. Then, analysis was performed by HPLC under the following conditions. The absorption intensity areas of the phenanthroline derivative represented by formula (1) and the phenanthroline derivative represented by formula (A) and / or formula (B) were calculated. Equipment: Shimadzu Corporation Nexera lite system (LC-40 series) Detector: Shimadzu Corporation photodiode array detector (SPD-M40) Column type: High-purity spherical silica gel particles with octyl-group chemically bonded packing material, reversed-phase column Theoretical plate number: 105,000±10,000(N / m) Column temperature: 45℃ Flow rate: 1.0mL / min Injection volume: 10μL Measurement sample concentration: 5.0 mg / 40 ml of tetrahydrofuran Mobile phase: Solution A: 0.1% by weight phosphoric acid aqueous solution, Solution B: Acetonitrile / tetrahydrofuran mixture (weight ratio 80 / 20) Flow conditions: Initially, the volume ratio of solution A to solution B was 55 / 45, and after a retention time of 25 minutes, only solution B was used, with a linear gradient for the first 25 minutes. Analysis software: Shimadzu Corporation Lab Solutions Measurement wavelength: 254nm Phenanthroline derivative detection area: 6,000,000 or more Minimum compound detection area: 60 Width(W):1sec Slope(S):1,000μV / min Drift(D):300μV / min T.DBL(T): 1,000 min.

[0068] (2) Structural analysis using a mass spectrometry system Among the phenanthroline derivatives obtained in each Example and Comparative Example, the structural formulas of the compounds having a peak between 12 and 13 minutes in retention time and the compounds having a peak between 7 and 8 minutes in retention time were detected by a mass spectrometry system directly connected to the elution port of the liquid chromatography. The mass spectrometry conditions were as follows: Equipment: Orbitrap Fusio Tribrid mass spectrometer (manufactured by Thermo Scientific) Ionization method: electrospray ionization Spray voltage:Static Positive ion: 3500V Measurement mode: Scan mode Vaporizer temperature: 400℃ Ion Transfer Tube temperature: 350℃ Sheath Gas: 60 Arb Aux Gas: 15 Arb Sweep Gas: 2 Arb MS / MS: Data-Dependent MSn scan mode Dissociation method: HCD Collision Energy Mode: Stepped Type:Normalized HCD collision energy: 35, 65, 95%.

[0069] (3) Driving voltage and durability of light-emitting element A glass substrate (manufactured by Geomatec Co., Ltd., 11 Ω / □, sputtered product) on which a 165 nm ITO transparent conductive film had been deposited was cut into 38 mm × 46 mm and etched. The resulting substrate was ultrasonically cleaned for 15 minutes using Semicoclean 56 (trade name, manufactured by Furuuchi Chemical Co., Ltd.) and then washed with ultrapure water. This substrate was UV-ozone treated for 1 hour immediately before fabricating the device, and then placed in a vacuum deposition apparatus, where the vacuum level in the apparatus was 5 × 10. -4 The chamber was evacuated until the pressure reached or below Pa. First, HAT-CN6 represented by the following formula (9) was deposited by resistance heating to a thickness of 5 nm as a hole injection layer, and then HT-1 represented by the following formula (10) was deposited by evaporation to a thickness of 50 nm as a hole transport layer.

[0070] [ka]

[0071] Next, a mixed layer of a host material H-1 represented by the following formula (11) and a dopant material D-1 represented by the following formula (12) was vapor-deposited to a thickness of 20 nm to form an emitting layer with a doping concentration of 5 wt %. Next, ET-1 represented by the following formula (13) was vapor-deposited to a thickness of 30 nm to form an electron transporting layer.

[0072] [ka]

[0073] Next, a mixed layer of the phenanthroline derivative and lithium obtained in each Example and Comparative Example was vapor-deposited to a thickness of 10 nm as an N-type charge generation layer, with the lithium doping concentration set to 1 wt%. Next, HAT-CN6 was vapor-deposited to a thickness of 10 nm as a P-type charge generation layer. Lithium fluoride was then vapor-deposited to a thickness of 0.5 nm, and aluminum was vapor-deposited to a thickness of 1000 nm as a cathode, resulting in a 5 mm x 5 mm square light-emitting device.

[0074] The obtained light-emitting device was subjected to a current of 10 mA / cm 2 The initial driving voltage was measured at a current density of 100 mA / cm under the conditions of a temperature of 20 to 30°C. 2 The luminance was measured when the device was driven with a direct current at 1000 kJ / s, and the time it took for the luminance to decrease by 5% from the initial luminance was evaluated as durability.

[0075] (4) Evaluation of durability of light-emitting elements when driven at high temperatures A light-emitting device was fabricated in the same manner as in (3), and the temperature was 50°C and the current density was 100 mA / cm. 2 The luminance was measured when the device was driven with a direct current at 100 Hz, and the time it took for the luminance to decrease by 10% from the initial luminance was evaluated as durability.

[0076] (5) Evaluation of voltage rise after high-temperature operation A light-emitting device was fabricated in the same manner as in (3), and the temperature was 50°C and the current density was 100 mA / cm. 2 After 1000 hours of continuous DC operation at 10mA / cm 2 The drive voltage when the device was driven with a direct current was measured, and the increase in voltage required for drive was evaluated by subtracting the initial drive voltage.

[0077] (Synthesis Example 1) To a mixed solution of 4.0 g of 1-bromo-3-chlorobenzene and 30 ml of tetrahydrofuran, 13 ml of n-butyllithium (1.6 M hexane solution) was added dropwise at 0°C under a nitrogen stream. After stirring at 0°C for 1 hour, the mixture was added dropwise to a mixed solution of 4.5 g of 2-phenyl-1,10-phenanthroline and 30 ml of tetrahydrofuran at 0°C. After cooling to room temperature, the reaction solution was extracted with dichloromethane, and the solvent was evaporated to 100 ml. To the resulting solution, 10.0 g of manganese dioxide was added and stirred at room temperature for 4 hours. After addition of magnesium sulfate and filtration, the solvent was removed by evaporation. The resulting solid was purified by silica gel column chromatography, and the resulting solid, which had been evaporated to remove the solvent, was dried under vacuum to obtain 6.0 g of an intermediate.

[0078] Next, a mixed solution of 3.0 g of this intermediate, 3.7 g of the boronic acid ester represented by the following formula (15), 160 mg of dichlorobis(triphenylphosphine)palladium(II), 7 ml of 1.5 M aqueous potassium phosphate solution, and 80 ml of 1,4-dioxane was heated and stirred under reflux for 7 hours under a nitrogen stream. After cooling to room temperature, water was added, the mixture was filtered, washed with methanol, and dried under vacuum. The catalyst was removed from the resulting solid using activated carbon, and the solvent was removed by evaporation. The resulting solid was washed with toluene and methanol and then dried under vacuum to obtain 4.4 g of a crude phenanthroline derivative.

[0079] [ka]

[0080] The crude product of the phenanthroline derivative obtained above was washed with a heated slurry of toluene, then recrystallized once with an anisole / toluene solution, and washed with a heated slurry of tetrahydrofuran / methanol solution. The crystals were purified by a 1.0×10 filtration method using an oil diffusion pump. -3 Sublimation purification was carried out three times at 320°C under a pressure of 100 Pa or less to obtain 3.0 g of the phenanthroline derivative of formula (3).

[0081] (Synthesis Example 2) 2.8 g of the phenanthroline derivative of formula (4) was obtained in the same manner as in Synthesis Example 1, except that 4.5 g of 2-phenyl-1,10-phenanthroline was changed to 4.1 g of 1,10-phenanthroline.

[0082] (Synthesis Example 3) A phenanthroline derivative of formula (5) was obtained in the same manner as in Synthesis Example 2, except that 1,10-phenanthroline was changed to 2-n-butyl-1,10-phenanthroline.

[0083] (Synthesis Example 4) A mixture of 3.0 g of 2-phenyl-9-chloro-1,10-phenanthroline, 1.6 g of 3-chlorophenylboronic acid, 220 mg of dichlorobis(triphenylphosphine)palladium(II), 7 ml of 1.5 M aqueous potassium phosphate solution, and 80 ml of 1,4-dioxane was heated and stirred under reflux for 7 hours under a nitrogen stream. After cooling to room temperature, water was added to precipitate a solid, which was then filtered, washed with methanol, and dried under vacuum. The resulting solid was dissolved in tetrahydrofuran, the catalyst was removed using activated carbon, and the solvent was evaporated. The resulting solid was washed with toluene and methanol and then dried under vacuum.

[0084] Next, 3.0 g of the resulting solid, 3.1 g of bis(pinacolato)diboron, 70 mg of tris(dibenzylideneacetone)dipalladium(0), 80 mg of 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl, 2.4 g of potassium acetate, and 80 mL of DMF were dissolved and stirred at 120 °C for 24 hours under a nitrogen stream. After cooling to room temperature, water was added to precipitate the solid, which was then filtered, washed with methanol, and dried under vacuum. The resulting solid was dissolved in tetrahydrofuran, the catalyst was removed using activated carbon, and the solvent was removed by evaporation. The resulting solid was washed with toluene and methanol, and then dried under vacuum.

[0085] Next, 3.0 g of the resulting solid, 0.99 g of 2,9-dichloro-1,10-phenanthroline, 280 mg of dichlorobis(triphenylphosphine)palladium(II), and 2.2 g of potassium carbonate were dissolved in a mixed solvent of 80 mL of 1,4-dioxane and 20 mL of pure water, and the solution was heated and stirred under reflux for 20 hours under a nitrogen atmosphere. After cooling to room temperature, the solvent was removed by evaporation. The resulting solid was recrystallized three times from a mixed solvent of tetrahydrofuran and methanol, and then vacuum-dried to obtain the phenanthroline derivative of formula (14).

[0086] Example 1 (Step 1) to (Step 4) were carried out according to the flow of the following conditions. Syringe pump: YMC Corporation Model YSP-301 high-performance high-pressure type Temperature: 10~30℃ Channel diameter (inner diameter) between mixers: 1 mm Material of flow passage between mixers: "Teflon" (registered trademark) Mixer shape: T-shaped Mixer material: "Teflon" (registered trademark) Mixer channel diameter: 1mm.

[0087] (Process 1) A 0.2 M 1,3-dibromobenzene / tetrahydrofuran solution was fed into the flow channel from server A at a flow rate of 5.0 ml / min, and a 0.2 M n-butyllithium / n-hexane solution was fed into the flow channel from server B at a flow rate of 4.6 ml / min, and the reaction was carried out in the first T-mixer. The flow rate of the reactants was 9.6 ml / min.

[0088] (Process 2) Two seconds after the first T-mixer, a 0.2 M 2-phenyl-1,10-phenanthroline / tetrahydrofuran solution was introduced from Server C into the flow channel at a flow rate of 4.2 ml / min, and reacted in the second T-mixer. The flow rate of the reactant was 13.8 ml / min.

[0089] (Step 3) Four seconds after the second T-mixer, a 0.2 M n-butyllithium / n-hexane solution was introduced into the flow channel from server D at a flow rate of 4.6 ml / min, and reacted in the third T-mixer. The flow rate of the reactant was 18.4 ml / min.

[0090] (Step 4) Two seconds after the third T-mixer, a mixed solution of 0.2 M 2-phenyl-1,10-phenanthroline / tetrahydrofuran solution and 0.032 mM 1,10-phenanthroline / tetrahydrofuran solution was flowed into the flow path from Server E at a flow rate of 4.2 mL / min, and reacted in the fourth T-mixer. 14 seconds after the fourth T-mixer, the reaction product was collected in a flask. However, the reaction product was collected one minute after the pump started. Next, (Step 5) and (Step 6) were performed using the following method (batch).

[0091] (Step 5) The temperature inside the flask was kept at 0 to 5°C using ice water, and 50 ml of the reaction product solution obtained in (Step 5) was collected. Next, the reaction product solution was stirred while keeping the temperature inside the flask at 0 to 5°C, and 5 ml of HO was added to quench the reaction. Next, 50 ml of dichloromethane was added to the quenched solution, and the reaction product was extracted.

[0092] To this extract solution, 50 ml of a dichloromethane solution containing 10 g of manganese dioxide dispersed therein was added while maintaining the temperature inside the flask at 30°C or below, and the mixture was then stirred for 15 minutes to oxidize. The resulting oxide solution was then filtered using a Kiriyama funnel (filter paper mesh: 4 μm), and the filtrate was concentrated to dryness using an evaporator at a bath temperature of 40°C, yielding 5.4 g of a mixed crude product of phenanthroline derivatives.

[0093] (Step 6) The mixed crude product of phenanthroline derivatives obtained in (Step 5) was washed with toluene as a slurry by heating, then recrystallized once with an anisole / toluene solution, and washed with a tetrahydrofuran / methanol solution by heating. The crystals were purified by a 1.0×10 -3The mixture was purified by sublimation once at 320°C under a pressure of 100 Pa or less to obtain 4.4 g of a phenanthroline derivative mixture.

[0094] The obtained mixture of phenanthroline derivatives was evaluated by the above-mentioned method. The results are shown in Table 1, and the absorption spectrum obtained by HPLC analysis is shown in FIG.

[0095] Analysis of the structural formulas using the mass spectrometry system (2) revealed that the compound having a peak between retention times of 12 and 13 minutes was the compound of formula (3), i.e., the phenanthroline derivative represented by formula (1), and the compound having a peak between retention times of 7 and 8 minutes was the compound of formula (4), i.e., the phenanthroline derivative represented by formula (A), based on the precursor ion and product ion values ​​in Table 3 and the mass spectrum of mass spectrometry shown in Figure 2.

[0096] Of the total absorption intensity area of ​​all peaks between retention times 7 and 20 minutes in Figure 1, which was 7,607,534, the absorption intensity area of ​​the phenanthroline derivative represented by formula (1) was 7,590,720, and the absorption intensity area of ​​the phenanthroline derivative represented by formula (4) was 1,238. The absorption intensity area of ​​the phenanthroline derivative represented by formula (4) was 0.016% of the absorption intensity area of ​​the phenanthroline derivative represented by formula (1).

[0097] The content of the phenanthroline derivative compound represented by formula (1) was calculated to be 99.78% based on the total absorption intensity area of ​​all peaks between 7 and 20 minutes of retention time and the absorption intensity area of ​​the phenanthroline derivative represented by formula (1). The content of the phenanthroline derivative compound represented by formula (4) was calculated to be 0.016% based on the absorption intensity area of ​​the phenanthroline derivative represented by formula (4). Furthermore, the light-emitting device (3) was fabricated and evaluated, and found to have a durability of 52.1 hours at an initial driving voltage of 8.5 V. The durability of the light-emitting device (4) at high temperature was evaluated to be 29.1 hours, and the voltage rise voltage at high temperature was evaluated to be 0.30 V.

[0098] Example 2 3.0 g of the phenanthroline derivative of formula (3) and 0.9 mg of the phenanthroline derivative of formula (4) were dissolved in a tetrahydrofuran / methanol solution, and the resulting solution was subjected to a 1.0×10 -3 Sublimation purification was performed once at 320°C under a pressure of 100 Pa or less, thereby obtaining 2.6 g of a mixture of the phenanthroline derivative of formula (3) and the phenanthroline derivative of formula (4). The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0099] Example 3 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3) and 0.03 mg of the phenanthroline derivative of formula (4) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0100] Example 4 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 3, except that the phenanthroline derivative represented by formula (5) was used instead of the phenanthroline derivative represented by formula (4). The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0101] Example 5 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3) and 0.45 mg of the phenanthroline derivative of formula (5) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0102] Example 6 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3) and 0.90 mg of the phenanthroline derivative of formula (5) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0103] Example 7 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3) and 1.0 mg of the phenanthroline derivative of formula (5) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0104] Example 8 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3) and 3.0 mg of the phenanthroline derivative of formula (5) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0105] Example 9 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3) and 9.0 mg of the phenanthroline derivative of formula (5) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0106] Example 10 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3) and 0.03 mg of the phenanthroline derivative of formula (14) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0107] Example 11 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3) and 0.45 mg of the phenanthroline derivative of formula (14) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0108] Example 12 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3) and 0.90 mg of the phenanthroline derivative of formula (14) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0109] Example 13 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3) and 1.0 mg of the phenanthroline derivative of formula (14) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0110] Example 14 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3) and 3.0 mg of the phenanthroline derivative of formula (14) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0111] Example 15 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3) and 9.0 mg of the phenanthroline derivative of formula (14) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0112] Example 16 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3), 0.03 mg of the phenanthroline derivative of formula (5), and 0.03 mg of the phenanthroline derivative of formula (14) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[0113] Example 17 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3), 0.45 mg of the phenanthroline derivative of formula (5), and 0.45 mg of the phenanthroline derivative of formula (14) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[0114] Example 18 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3), 4.5 mg of the phenanthroline derivative of formula (5), and 4.5 mg of the phenanthroline derivative of formula (14) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[0115] Example 19 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3), 0.03 mg of the phenanthroline derivative of formula (4), and 0.03 mg of the phenanthroline derivative of formula (14) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[0116] Example 20 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3), 0.45 mg of the phenanthroline derivative of formula (4), and 0.45 mg of the phenanthroline derivative of formula (14) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[0117] Example 21 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3), 4.5 mg of the phenanthroline derivative of formula (4), and 4.5 mg of the phenanthroline derivative of formula (14) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[0118] (Comparative Example 1) A phenanthroline derivative was obtained in the same manner as in Example 1, except that the solution flowing from server E in (Step 4) was a 0.2 M 2-phenyl-1,10-phenanthroline / tetrahydrofuran solution alone. The evaluation results are shown in Table 1.

[0119] (Comparative Example 2) A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3) and 12.0 mg of the phenanthroline derivative of formula (4) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[0120] (Comparative Example 3) A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3) and 12.0 mg of the phenanthroline derivative of formula (5) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[0121] Comparative Example 4 A mixture of phenanthroline derivatives was obtained in the same manner as in Example 2, except that 3.0 g of the phenanthroline derivative of formula (3) and 12.0 mg of the phenanthroline derivative of formula (14) were dissolved in a tetrahydrofuran / methanol solution. The obtained mixture of phenanthroline derivatives was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[0122] [Table 1]

[0123] [Table 2]

[0124] [Table 3]

[0125] The results in Tables 1 and 2 show that when the absorption intensity area of ​​the phenanthroline derivative represented by formula (4) and / or formula (5) and / or formula (14), i.e., the phenanthroline derivative represented by formula (A) and / or the following formula (B), when analyzed by high performance liquid chromatography, is 0.001% to 0.300% of the absorption intensity area of ​​the phenanthroline derivative represented by formula (1), an element with excellent durability can be obtained.

Claims

1. A composition containing a phenanthroline derivative represented by the following formula (1), and a phenanthroline derivative represented by the following formula (A) and / or formula (B), wherein, when analyzed by high performance liquid chromatography, the absorption intensity area of ​​the phenanthroline derivative represented by the following formula (A) and / or formula (B) is 0.001% to 0.300% of the absorption intensity area of ​​the phenanthroline derivative represented by the following formula (1), and the phenanthroline derivative represented by the formula (A) and / or formula (B) is one or more compounds selected from the group consisting of the following formulas (4), (5), and (14), and the conditions for the analysis by high performance liquid chromatography are as follows: 【Chemistry 1】 (X and Y each independently represent a substituted or unsubstituted aryl group. X and Y may be the same or different.) 【Chemistry 2】 (X represents a substituted or unsubstituted aryl group; R represents a hydrogen atom, a halogen atom, a cyano group, or a substituted or unsubstituted alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, or alkoxy group having 1 to 9 carbon atoms; and Z represents a substituted aryl group. However, the phenanthroline derivative represented by general formula (B) has a structure different from that of the phenanthroline derivative represented by general formula (1).) 【Transformation 3】 Equipment: Shimadzu Corporation Nexera (registered trademark) lite system (LC-40 series) Detector: Photodiode array detector (SPD-M40) manufactured by Shimadzu Corporation Column: High-purity spherical silica gel particle octyl group chemically bonded packing reversed phase column Theoretical plate number: 105,000 ± 10,000 (N / m) Column temperature: 45°C Flow rate: 1.0mL / min Injection volume: 10μL Measurement sample concentration: 5.0 mg / 40 ml of tetrahydrofuran Mobile phase: Solution A: 0.1% by weight phosphoric acid aqueous solution, Solution B: acetonitrile / tetrahydrofuran mixed solution (weight ratio 80 / 20) Flow conditions: Initially, the volume ratio of solution A to solution B was 55 / 45, and after a retention time of 25 minutes, only solution B was used, with a linear gradient for the first 25 minutes. Analysis software: Lab Solutions manufactured by Shimadzu Corporation Measurement wavelength: 254nm Phenanthroline derivative detection area: 6,000,000 or more Minimum compound detection area: 60 Width (W): 1sec Slope (S): 1,000μV / min Drift (D): 300μV / min T. DBL(T): 1,000 minutes

2. 2. A composition containing the phenanthroline derivative according to claim 1, wherein the phenanthroline derivative represented by formula (1) is a phenanthroline derivative represented by the following formula (3): 【Chemistry 4】

3. 2. The composition containing the phenanthroline derivative according to claim 1, wherein the phenanthroline derivative represented by the formula (A) and / or the formula (B) is two or more compounds selected from the group consisting of the formula (4), the formula (5), and the formula (14).

4. The composition containing the phenanthroline derivative according to claim 3, wherein the phenanthroline derivative represented by the formula (A) and / or the formula (B) includes at least both the compound represented by the formula (5) and the compound represented by the formula (14).

5. The composition containing the phenanthroline derivative according to claim 1, wherein the absorption intensity area of ​​the phenanthroline derivative represented by formula (A) and / or formula (B) is 0.001% to 0.030% of the absorption intensity area of ​​the phenanthroline derivative represented by formula (1) when analyzed by high performance liquid chromatography.

6. 2. A method for producing a composition containing the phenanthroline derivative according to claim 1, comprising, in this order: (Step 1) reacting a 1,3-dihalogenated aromatic compound with an organolithium reagent; (Step 2) reacting the lithiation reaction product of Step 1 with a phenanthroline derivative of the following formula (6); (Step 3) reacting the reaction product of Step 2 with an organolithium reagent; (Step 4) reacting the lithiation reaction product of Step 3 with a phenanthroline derivative of the following formula (7) and a phenanthroline derivative of the following formula (8); (Step 5) oxidizing the reaction product of Step 4 to obtain a crude product of the phenanthroline derivative; and (Step 6) recrystallizing and further sublimating the crude product of the phenanthroline derivative of Step 5. 【Transformation 5】 (X and Y each independently represent a substituted or unsubstituted aryl group. R represents a hydrogen atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 9 carbon atoms, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group, or an alkoxy group.)

7. A light-emitting device comprising a composition containing the phenanthroline derivative according to any one of claims 1 to 5.

8. A display device comprising the light-emitting element according to claim 7.

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