Phenanthroline derivative and method for producing phenanthroline derivative

Abstract

[Problem] The purpose of the present invention is to obtain a phenanthroline derivative with which it is possible to suppress a decrease in luminous efficiency even at a higher current density than conventional phenanthroline derivatives. [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 a phenanthroline derivative represented by a specific formula (A) and / or a specific formula (B) is 0.001-0.300% with respect to the absorption intensity area of a phenanthroline derivative represented by specific formula (1).

Description

Phenanthroline derivatives and method for producing the same

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

[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 in which 2 to 5 phenylene groups are bonded is suppressed.

[0004] The invention was to produce a phenanthroline derivative by a production method comprising, in this order, continuously 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 the crude product of the phenanthroline derivative of Step 5A and further sublimating it.

[0005] JP 2023-45495 A

[0006] However, although the phenanthroline derivative of the invention of Patent Document 1 has the effect of being able to obtain a light-emitting device with low driving voltage and excellent durability, for example, in the case of a light-emitting device driven by a passive matrix, 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, and there is a concern that the remaining lithiation reaction product may be oxidized to generate new impurities. Therefore, in order to remove the new impurities and obtain a phenanthroline derivative of high purity, there is a problem in that the crude product of the phenanthroline derivative must be recrystallized and further sublimated (Step 6A) 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.

[0009] That is, the present invention is as follows: [1] A phenanthroline derivative whose main component is represented by the following formula (1), in which, 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]

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

[0012]

[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 formula (1) is a phenanthroline derivative represented by formula (3) described later. [3] The phenanthroline derivative according to [1] or [2], wherein the phenanthroline derivative represented by formula (A) and / or formula (B) is one or more compounds selected from the group consisting of formula (4) described later, formula (5) described later, and formula (14) described later. [4] The phenanthroline derivative according to [3], wherein the phenanthroline derivative represented by formula (A) and / or formula (B) is two or more compounds selected from the group consisting of formula (4), formula (5), and formula (14). [5] The phenanthroline derivative according to [4], wherein the phenanthroline derivative represented by formula (A) and / or formula (B) contains at least both the compound represented by formula (5) and the compound represented by 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 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. [7] The phenanthroline derivative according to any one of [1] to [6], wherein the high-performance liquid chromatography analysis conditions are as follows:Instrument: Nexera lite system (LC-40 series) manufactured by Shimadzu Corporation 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: 1.0 mL / min Injection volume: 10 μL Measurement sample concentration: 5.0 mg / 40 ml tetrahydrofuran Mobile phase: Solution A: 0.1 wt% phosphoric acid aqueous solution, Solution B: acetonitrile / tetrahydrofuran mixture (weight ratio 80 / 20) Flow conditions: Initially, solution A / solution B volume ratio 55 / 45, after 25 minutes of retention time, solution B only, linear gradient for the first 25 minutes Analysis software: Lab Solutions manufactured by Shimadzu Corporation Measurement wavelength: 254 nm Phenanthroline derivative detection area: 6,000,000 or more Minimum compound detection area: 60 Width (W): 1 sec Slope (S): 1,000 μV / min Drift (D): 300 μV / min T. DBL (T): 1,000 min [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 later; (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 later and a phenanthroline derivative of Formula (8) described later; (Step 5) oxidizing the reaction product of Step 4 to obtain a crude product of the phenanthroline derivative; and (Step 6) recrystallizing and sublimating the crude product of the phenanthroline derivative of Step 5. [9] A light-emitting device comprising the phenanthroline derivative according to any one of [1] to [7].

[10] A display device comprising the light-emitting device according to [9].

[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 having the effect of significantly improving productivity.

[0015] 1 shows an absorption spectrum obtained by HPLC analysis of the phenanthroline derivative obtained in Example 1. Among the absorption spectra obtained by HPLC analysis of the phenanthroline derivative obtained in Example 1, this shows a mass spectrum including a detection peak (511.19 [M+H]) of the compound represented by formula (A) in mass spectrometry. Among the absorption spectra obtained by HPLC analysis of the phenanthroline derivative obtained in Example 4, this shows a mass spectrum including a detection peak (567.25 [M+H]) of the compound represented by formula (B) in mass spectrometry.

[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]

[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]

[0022] The phenanthroline derivatives used as organic light-emitting element materials and the like, which are the main component represented by the formula (1), may contain metal ions, halogen-containing compounds, by-products, solvents, etc. derived from the raw materials. From the viewpoint of suppressing bumping during sublimation purification and further improving the properties of light-emitting elements such as low-voltage driving and durability, the higher the purity of the phenanthroline derivatives as the main component represented by the 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 the formula (A) and / or the formula (B) exceeds 0.300% of the absorption intensity area of ​​the phenanthroline derivative represented by the formula (1), it is considered that this will adversely affect the electrical properties of the phenanthroline derivative represented by the formula (1), and the durability will be reduced. On the other hand, if the absorption intensity area of ​​the phenanthroline derivative represented by the formula (A) and / or the formula (B) is less than 0.001% of the absorption intensity area of ​​the phenanthroline derivative represented by the formula (1), it is considered that the effects of the present invention will be difficult to obtain, and sufficient durability will not be obtained.

[0026] This durability improvement effect is particularly significant 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 difficult for the crystals that cause deterioration 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. Instrument: Nexera lite system (LC-40 series) manufactured by Shimadzu Corporation 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: 1.0 mL / min Injection volume: 10 μL Measurement sample concentration: 5.0 mg / 40 ml tetrahydrofuran Mobile phase: Solution A: 0.1 wt% phosphoric acid aqueous solution, Solution B: acetonitrile / tetrahydrofuran mixture (weight ratio 80 / 20) Flow conditions: Initially, solution A / solution B volume ratio 55 / 45, after 25 minutes of retention time, solution B only, linear gradient for the first 25 minutes Analysis software: Lab Solutions manufactured by Shimadzu Corporation Measurement wavelength: 254 nm Phenanthroline derivative detection area: 6,000,000 or more Minimum compound detection area: 60 Width (W): 1 sec Slope (S): 1,000 μV / min Drift (D): 300 μV / min T. DBL (T): 1,000 min.

[0029] The above-mentioned instruments and detectors used in HPLC analysis have the advantage of a wide dynamic range when simultaneously analyzing multiple compounds with significantly different contents, such as main components and by-products, making it possible to simultaneously analyze compounds of 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.). A column size of 250 mm in length and 4.6 mm in inner diameter (5 μm particle diameter) can be selected. The column temperature, flow rate, injection volume, and measurement sample concentration used in the analysis are all general-purpose conditions.

[0032] As the mobile phase, solution A, a 0.1 wt% aqueous solution of phosphoric acid, and solution B, an acetonitrile / tetrahydrofuran mixture (weight ratio 80 / 20), were prepared. The volume ratio of solution A / solution B was initially set to 55 / 45, and after a retention time of 25 minutes, only solution B was used. During this period (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, and 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 the above conditions, the content of each component eluted from the column can be qualitatively and quantitatively analyzed from the ultraviolet absorption spectrum at a measurement wavelength of 254 nm. Specifically, using Lab Solutions manufactured by Shimadzu Corporation as analysis software, the conditions for uniformly detecting small peaks are as follows: Width (W), which represents the minimum detectable peak width, is 1 sec; Slope (S), which represents the peak detection sensitivity and determines the peak start / end points, is 300 μV / min; Drift (D), which represents the slope for completely separating the peaks (baseline separation), is 300 μV / min; and the specified time T.DBL (T), which changes the values ​​of Slope and Drift, is 1,000 min.

[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 by setting an area of ​​0.001% or more of that as the minimum detection area of ​​the compound. As an example, Figure 1 shows an 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 peaks of the phenanthroline derivatives represented by formula (A) and / or formula (B) are detected at a retention time of 7 to 8 minutes.

[0037]

[0038] The phenanthroline derivative represented by the formula (A) has a structure in which Y in the phenanthroline derivative represented by the 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 a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, etc. The cycloalkyl group refers to a saturated alicyclic hydrocarbon group such as a cyclopropyl group, a cyclohexyl group, a norbornyl group, adamantyl group, etc. The alkenyl group refers to an unsaturated aliphatic hydrocarbon group containing a double bond such as a vinyl group, a butadienyl group, etc.

[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 those 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]

[0044] The phenanthroline derivatives represented by the formula (A) and / or the formula (B) exhibit a property of suppressing a decrease in luminous efficiency at high current densities by being present in an extremely small amount relative to the phenanthroline derivative represented by the formula (1). Although the mechanism is not clear, it is presumed that this is because the deactivation of active species of excitons, particularly triplet excitons, generated by operation at high current densities is suppressed, allowing these excitons to be continuously utilized 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]

[0048] Alternatively, the following production method may be mentioned, in which the phenanthroline derivative of the formula (1) and the phenanthroline derivative of the formula (A) are continuously and simultaneously synthesized 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, leaving the lithiation reaction product of step 3 behind, 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, thereby suppressing the generation of new impurities.

[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 (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 an extremely small amount of the phenanthroline derivative of formula (A) can be obtained. As a result, a phenanthroline derivative having excellent properties, which 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 may be carried out in a batch process, but to further improve productivity, steps 1 to 4 may be carried out in 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 by 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 produced compound is 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 the form of a solution, 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 the 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 consideration 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 aforementioned 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 derivative. Furthermore, taking into account the time required for the reaction of phenanthroline, the residence time in (Step 2) is preferably 4 to 6 seconds. 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 that of 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 As described above, by the method for producing a phenanthroline derivative of the present invention, it is possible to easily obtain a phenanthroline derivative in which 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).

[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 each of the phenanthroline derivatives obtained in each Example and Comparative Example was weighed into a glass container, and 40 ml of tetrahydrofuran was added to dissolve the derivative. 1 ml of the resulting solution was transferred to an HPLC vial to prepare an HPLC measurement sample. Analysis was then 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. Instrument: Nexera lite system (LC-40 series) manufactured by Shimadzu Corporation Detector: Photodiode array detector (SPD-M40) manufactured by Shimadzu Corporation Column type: 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: 1.0 mL / min Injection volume: 10 μL Measurement sample concentration: 5.0 mg / 40 ml tetrahydrofuran Mobile phase: Solution A: 0.1 wt% phosphoric acid aqueous solution, Solution B: acetonitrile / tetrahydrofuran mixture (weight ratio 80 / 20) Solution delivery conditions: Initially, solution A / solution B volume ratio 55 / 45, after 25 minutes of retention time, only solution B was used, linear gradient for the first 25 minutes Analysis software: Lab Solutions manufactured by Shimadzu Corporation Measurement wavelength: 254 nm Phenanthroline derivative detection area: 6,000,000 or more Minimum compound detection area: 60 Width (W): 1 sec Slope (S): 1,000 μV / min Drift (D): 300 μV / min T. DBL (T): 1,000 min.

[0068] (2) Analysis of structural formulas by 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 conditions for mass spectrometry are as follows: Equipment: Orbitrap Fusio Tribrid mass spectrometer (manufactured by Thermo Scientific) Ionization method: electrospray ionization Spray voltage: static positive ion: 3500 V Measurement mode: scan mode Vaporizer temperature: 400°C Ion transfer tube temperature: 350°C 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 a size of 38 mm x 46 mm and etched. The obtained 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 subjected to UV-ozone treatment for 1 hour immediately before fabricating the element, and then placed in a vacuum deposition apparatus, and the degree of vacuum in the apparatus was adjusted to 5 x 10. －４ The chamber was evacuated to a pressure of 100 Pa or less. 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]

[0071] Next, as an emitting layer, 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 so that the doping concentration was 5 wt %. Next, as an electron-transporting layer, ET-1 represented by the following formula (13) was vapor-deposited to a thickness of 30 nm.

[0072]

[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 so that the lithium doping concentration was 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 to form a cathode, resulting in a 5 mm x 5 mm 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 100 Ω / s, and the time required for the luminance to decrease by 5% from the initial luminance was evaluated as durability.

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

[0076] (5) Evaluation of voltage increase after high-temperature operation A light-emitting device was fabricated in the same manner as in (3), and the device was driven at a temperature of 50° C. and a current density of 100 mA / cm ２ After 1000 hours of continuous DC driving at 10 mA / 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, leaving 100 ml. To the resulting solution, 10.0 g of manganese dioxide was added, and the mixture was stirred at room temperature for 4 hours. After that, magnesium sulfate was added, and the mixture was filtered, and the solvent was removed by evaporation. The resulting solid was purified by silica gel column chromatography, and the solid obtained by removing the solvent by evaporation was dried in vacuo, yielding 6.0 g of an intermediate.

[0078] Next, a mixed solution of 3.0 g of this intermediate, 3.7 g of a boronic acid ester represented by the following formula (15), 160 mg of dichlorobis(triphenylphosphine)palladium(II), 7 ml of a 1.5 M aqueous solution of tripotassium phosphate, 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, yielding 4.4 g of a crude phenanthroline derivative.

[0079]

[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 then 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 1000 kJ or less, thereby obtaining 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 mixed solution 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 removed by evaporation. The resulting solid was washed with toluene and methanol and then dried under vacuum.

[0084] Subsequently, 3.0 g of the obtained 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 a solid, which was then filtered, washed with methanol, and dried under vacuum. The obtained 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] Subsequently, 3.0 g of the obtained 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 stream. After cooling to room temperature, the solvent was removed by evaporation, and the obtained 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 conditions below: Syringe pump: Model YSP-301 high performance high pressure type manufactured by YMC Corporation Temperature: 10 to 30°C Flow path diameter (inner diameter) between mixers: 1 mm Flow path material between mixers: "Teflon" (registered trademark) Mixer shape: T-shaped Mixer material: "Teflon" (registered trademark) Mixer flow path diameter: 1 mm.

[0087] (Step 1) A 0.2 M 1,3-dibromobenzene / tetrahydrofuran solution was flowed into the flow path from server A at a flow rate of 5.0 ml / min, and a 0.2 M n-butyllithium / n-hexane solution was flowed into the flow path 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] (Step 2) Two seconds after the first T-shaped mixer, a 0.2 M 2-phenyl-1,10-phenanthroline / tetrahydrofuran solution was flowed into the flow channel from server C at a flow rate of 4.2 ml / min, and reacted in the second T-shaped mixer. The flow rate of the reactant was 13.8 ml / min.

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

[0090] (Step 4) Two seconds after the third T-mixer section, 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 section. 14 seconds after the fourth T-mixer section, the reaction product was collected in a flask. However, the reaction product was collected one minute after the pump started operating. Subsequently, (Step 5) and (Step 6) were carried out by 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 H ２ The reaction mixture was quenched by adding 5 ml of O. Then, 50 ml of dichloromethane was added to the quenched solution to extract the reaction mixture.

[0092] To this extract solution, 50 ml of a dichloromethane solution containing 10 g of manganese dioxide dispersed therein was added while maintaining the internal temperature of 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 the phenanthroline derivatives obtained in (Step 5) was washed with toluene by heating and slurry, then recrystallized once with an anisole / toluene solution, and washed with tetrahydrofuran / methanol by heating and slurry. The crystals were purified by an oil diffusion pump to a concentration of 1.0 × 10 －３ The mixture was purified by sublimation once at 320° C. under a pressure of 1000 kJ / cm 2 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 values ​​and product ion values ​​in Table 3 and the mass spectrum of mass spectrometry shown in FIG. 2 .

[0096] Of the total absorption intensity area of ​​7,607,534 for all peaks between retention times of 7 minutes and 20 minutes in Fig. 1, 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 retention times of 7 and 20 minutes 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 (3) light-emitting device was fabricated and evaluated, and found to have a durability of 52.1 hours at an initial driving voltage of 8.5 V. The (4) light-emitting device was evaluated for durability during high-temperature operation, and found to have a durability of 29.1 hours. The (5) light-emitting device was evaluated for voltage rise during high-temperature operation, and found to have a voltage rise of 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 solution was again subjected to a 1.0×10 －３ The mixture was purified by sublimation 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 the formula (3) and the phenanthroline derivative of the 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]

[0123]

[0124]

[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 having excellent durability can be obtained.

Claims

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, 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). (X and Y each independently represent a substituted or unsubstituted aryl group. X and Y may be the same or different.) (X represents a substituted or unsubstituted aryl group; 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; 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).) 2. 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):

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

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

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

6. 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.

7. The phenanthroline derivative according to claim 1, wherein the conditions for the high performance liquid chromatography analysis are as follows: Instrument: Nexera lite system (LC-40 series) manufactured by Shimadzu Corporation 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: 1.0 mL / min Injection volume: 10 μL Measurement sample concentration: 5.0 mg / 40 ml tetrahydrofuran Mobile phase: Solution A: 0.1 wt% phosphoric acid aqueous solution, Solution B: acetonitrile / tetrahydrofuran mixture (weight ratio 80 / 20) Flow conditions: Initially, solution A / solution B volume ratio 55 / 45, after 25 minutes of retention time, solution B only, linear gradient for the first 25 minutes Analysis software: Lab Solutions manufactured by Shimadzu Corporation Measurement wavelength: 254 nm Phenanthroline derivative detection area: 6,000,000 or more Minimum compound detection area: 60 Width (W): 1 sec Slope (S): 1,000 μV / min Drift (D): 300 μV / min T. DBL (T): 1,000 min 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 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 phenanthroline derivative; and (Step 6) recrystallizing and sublimating the crude phenanthroline derivative of Step 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, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, or an alkoxy group.) 9. A light-emitting device comprising the phenanthroline derivative according to any one of claims 1 to 7.

10. A display device comprising the light-emitting element according to claim 9.

Images