Metal complex and electron transport material using the same

Abstract

The present invention provides a novel metal complex that can be used as an electron transport material. The metal complex is represented by the following formula (1) to the following formula (3). A1 ~R A9 , R C1 ~R C8 , R E1 ~R E6 are independently a single bond, an alkylene group, an arylene group, a heteroarylene group or -R P1 ‑P(=O)R P2 ‑R P3 ‑represented group, R B1 ~R B9 , R D1 ~R D8 , R F1 ~R F6 are independently a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an amino group, a cyano group, a halogen atom or a hydroxyl group; B1 ~R B9 One or more of the group consisting of R D1 ~R D8 One or more of the group consisting of and selected from R F1 ~R F6 At least one of the groups is a phenanthroline group; M is an alkali metal or an alkaline earth metal; Z is 1 or 2; and X is O or S.

Description

Technical Field

[0001] The present invention relates to a novel alkali metal complex and an alkaline earth metal complex. In addition, the present invention also relates to an electron transport material for an organic electroluminescent element using the novel metal complex. More specifically, the present invention relates to an electron transport material that can be formed by a wet process in the manufacture of an organic electroluminescent element having a multilayer structure and has excellent electron injection properties, electron transport properties, and durability. Background Art

[0002] Organic electroluminescent elements (hereinafter sometimes referred to as "organic EL elements") having a luminescent organic layer (organic electroluminescent layer) between the anode and the cathode can be driven at a DC low voltage compared to inorganic EL elements, and have advantages of high brightness and luminous efficiency, and have attracted wide attention as next-generation display devices. For the full-color display panels that have recently been launched, research and development for larger display surfaces and improved durability are being widely carried out.

[0003] Organic EL elements are electronic light-emitting elements that emit light by electrically exciting organic compounds through the recombination of injected electrons and holes. In the past, since Tang et al. of Kodak Company reported that organic laminated thin film elements emit light at high brightness (see non-patent document 1), many companies and research institutions have conducted research on organic EL elements. The representative structure of Kodak's organic EL element is: a diamine compound as a hole transport material, tris(8-hydroxyquinoline)aluminum(III) as a light-emitting material, and Mg:Ag as a cathode are sequentially layered on an ITO (indium tin oxide) glass substrate as a transparent anode, and about 1000 cd / cm is observed at a driving voltage of about 10V. 2 The structure of the stacked organic EL element currently under research and practical use is basically the same as that of Kodak.

[0004] In a stacked organic EL element, the performance of the electron transport layer, electron injection layer, and hole transport layer provided between the light-emitting organic layer and the electrode greatly affects the characteristics of the device. Therefore, research and development aimed at improving these performances is in full swing, and there are also many reports on improved research on the electron transport layer and the electron injection layer.

[0005] For example, Patent Document 1 proposes the following structure: by co-evaporating an organic compound having electron transport properties and a metal compound containing a metal having a low work function (electronegativity), namely an alkali metal, thereby mixing the metal compound into the electron injection layer, an attempt is made to improve the characteristics of the electron injection layer. In addition, Patent Document 2 proposes the use of a phosphine oxide compound as an electron transport material. Furthermore, Patent Document 3 proposes a method of doping an alkali metal in an organic compound having a coordination site as a structure of an electron transport layer.

[0006] On the other hand, the manufacturing methods of organic EL elements can be roughly divided into: a vapor deposition method in which various materials are deposited on a substrate, and a wet method in which a solution of various materials is applied to a substrate and then dried. The wet method has the advantages of not requiring a vacuum, high productivity, and easy large-area formation, so the manufacture of laminated organic EL elements using the wet method will become increasingly important in the future.

[0007] There are two methods for manufacturing laminated organic EL elements using a wet process. One is a method in which the lower layer is formed into a film and then crosslinked or polymerized by heat or light to make it insoluble and then the upper layer is formed into a film. The other is a method in which materials with large solubility differences are used for the upper and lower layers. The former method has a wide range of material selection, but on the contrary, it is difficult to remove the reaction initiator or unreacted product after the crosslinking or polymerization reaction is completed, and there are problems with durability. On the other hand, the latter method has difficulty in selecting materials, but on the contrary, it is not accompanied by chemical reactions such as crosslinking or polymerization. Therefore, compared with the former method, a high-purity and high-durability element can be constructed. As mentioned above, although the manufacture of laminated organic EL elements using a wet process has the problem of difficulty in selecting materials, it is believed that the latter method, which utilizes the different solubility of the materials constituting each layer, is more suitable. However, one of the reasons why stacking using different solubility of constituent materials is difficult to manufacture is that conductive polymers or spin-coated organic semiconductors are almost all soluble only in solvents with high solvent performance such as toluene, chloroform, and tetrahydrofuran. After forming a hole transport layer or a light-emitting layer, if the same solvent is used to form the next layer, the hole transport layer or the light-emitting layer of the base will be corroded, and a stacking structure with a flat interface with few defects cannot be formed. In particular, when using the inkjet method, the solvent is naturally dried and removed, so the residence time of the solvent becomes longer, the hole transport layer or the light-emitting layer is severely corroded, and it may become very difficult to obtain device characteristics that are not problematic in practical use.

[0008] However, the purpose of the electron injection layer, electron transport material and electron transport layer described in Patent Documents 1 to 3 is to try to reduce the operating voltage or improve the luminous efficiency. It is difficult to say that the formation of a multilayer structure using a wet method or the improvement of durability has been achieved. In addition, in these inventions, the electron transport layer and the electron injection layer are formed by vacuum evaporation, so large equipment is required, and it is difficult to precisely adjust the evaporation speed when evaporating two or more materials at the same time, which has the problem of poor productivity.

[0009] Patent Document 4 proposes a metal complex having a heteroaryl group or a derivative thereof as a ligand, which is useful as a charge transport material for an EL element. However, no sufficient studies have been conducted on the formation of a multilayer structure by a wet method or the improvement of durability.

[0010] Therefore, the present inventors have developed an alcohol-soluble material which can be coated on a hole transport layer or a light-emitting layer generally formed of a hole transport material or a light-emitting material which is poorly soluble in alcohol (Patent Documents 5 and 6).

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent Document 1: Japanese Patent Application Publication No. 2005-63910

[0014] Patent Document 2: Japanese Patent Application Publication No. 2002-63989

[0015] Patent Document 3: Japanese Patent Application Publication No. 2002-352961

[0016] Patent Document 4: U.S. Patent Application Publication No. 2018 / 0175307

[0017] Patent Document 5: International Publication No. 2011 / 021385

[0018] Patent Document 6: International Publication No. 2018 / 021406

[0019] Non-patent literature

[0020] Non-patent document 1: CW Tang, SAVan Slyke, "Organic electroluminescent diodes", Applied Physics Letters (USA), The American Institute of Physics, September 21, 1987, Vol. 51, No. 12, pp. 913-915 Summary of the invention

[0021] Problem that the invention aims to solve

[0022] When manufacturing organic EL elements by wet method, most of them are manufactured from the anode side, and the choice of solvent for the liquid material used to form the hole transport layer is relatively free. On the other hand, the solvent of the liquid material used to form the electron transport layer is limited by the solubility of the hole transport layer or the light-emitting layer. Therefore, compared with the evaporation method, the current situation of the wet method is that the freedom of choice of electron transport materials becomes lower. New materials with electron transport properties that can also be used in the wet method can expand the range of choices of electron transport materials.

[0023] In addition, the electron transport materials described in Patent Documents 5 and 6 have room for improvement from the viewpoint of durability. Therefore, a new material that can be expected to have further improved performance is sought.

[0024] The present invention is carried out in view of the above situation, and the object of the present invention is to provide an alkali metal complex and an alkaline earth metal complex (hereinafter, sometimes referred to as "metal complex") having both electron transport and alcohol solubility. In addition, the object of the present invention is to provide a coordination compound constituting the alkali metal complex and the alkaline earth metal complex. In addition, the object of the present invention is also to provide an electron transport material, which uses the metal complex and can be formed by a wet method in the manufacture of an organic electroluminescent element with a multilayer structure, and has excellent electron injection characteristics, electron transport characteristics, and durability. Furthermore, the object of the present invention is also to provide an organic electroluminescent element using the electron transport material.

[0025] Means of solving the problem

[0026] According to the above purpose, the first embodiment of the present invention relates to the following novel metal complex. The metal complex having a novel coordination compound of the present invention is a novel metal complex suitable as an electron transport material for an organic electroluminescent element and having both electron transport properties and alcohol solubility. By using it alone or as an electron transport material further containing a metal alkoxide, the durability of the electroluminescent element is improved.

[0027] <1> A metal complex comprising at least one phenanthroline group and a nitrogen-containing condensed ring, and represented by the following formula (1) to (3).

[0028] [Chemical formula 1]

[0029]

[0030] In formulas (1) to (3),

[0031] R A1 ~R A9 , R C1 ~R C8 , R E1~R E6 Each is independently a single bond, an alkylene group, an arylene group, a heteroarylene group or a group represented by the following formula (4):

[0032] [Chemical formula 2]

[0033] -R P1 -P(=O)R P2 -R P3 - (4)

[0034] (In formula (4), R P1 , R P3 are independently a single bond, an alkylene group, an arylene group, or a heteroarylene group, and R P2 is alkyl, aryl, or heteroaryl. );

[0035] R B1 ~R B9 , R D1 ~R D8 , R F1 ~R F6 are each independently a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an amino group, a cyano group, a halogen atom or a hydroxyl group;

[0036] Selected from R B1 ~R B9 At least one of the group consisting of is a phenanthroline group, selected from R D1 ~R D8 At least one of the groups consisting of is a phenanthroline group, selected from R F1 ~R F6 One or more of the group consisting of is a phenanthroline group;

[0037] M is an alkali metal or an alkaline earth metal,

[0038] Z is 1 or 2,

[0039] X is O or S.

[0040] <2> Said <1> The metal complex described above, wherein the phenanthroline group is selected from the group consisting of groups represented by the following formula (5a) to the following formula (5d).

[0041] [Chemical formula 3]

[0042]

[0043] In formula (5a) to formula (5d), R G2 ~R G9 Each of them is independently a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an amino group, a cyano group, a halogen atom, a hydroxyl group or a group represented by the following general formula (6):

[0044] [Chemical formula 4]

[0045] -R P4 -P(=O)R P5 -R P6 (6)

[0046] (In formula (6), R P4 is a single bond, an alkylene group, an arylene group, or a heteroarylene group, and R P5 , R P6 are independently alkyl, aryl or heteroaryl. ).

[0047] <3> Said <1> or <2> The metal complex described herein, wherein the R A1 ~R A9 , the R C1 ~R C8 , the R E1 ~R E6 Each of them is independently a single bond, an alkylene group having 1 to 4 carbon atoms, a phenylene group, a naphthylene group, a pyridylene group, a bipyridylene group, a pyrimidylene group or a group represented by the above formula (4).

[0048] <4> Said <1> ~ <3> The metal complex according to any one of the preceding claims, wherein R B1 ~R B9 , the R D1 ~R D8 , the R F1 ~R F6 are each independently a hydrogen atom or a phenanthroline group.

[0049] <5> Said <1> ~ <4> The metal complex according to any one of the above items, wherein the metal complex is any one selected from the group consisting of compounds represented by the following L101-M to L108-M, L201-M to L-212-M, and L301-M to L320-M.

[0050] [Chemical formula 5]

[0051]

[0052] [Chemical formula 6]

[0053]

[0054] [Chemical formula 7]

[0055]

[0056] [Chemical formula 8]

[0057]

[0058] [Chemical formula 9]

[0059]

[0060] [Chemical formula 10]

[0061]

[0062] [Chemical formula 11]

[0063]

[0064] <6> Said <1> ~ <5> The metal complex according to any one of items, wherein M is an alkali metal.

[0065] <7> Said <6> The metal complex described herein, wherein the alkali metal is Rb or Cs.

[0066] Next, according to the above-mentioned object, a second aspect of the present invention relates to a coordinating compound used in the above-mentioned metal complex.

[0067] <8> A coordination compound, which is used for <1> ~ <7> The metal complex according to any one of items.

[0068] Next, according to the above-mentioned purpose, the third aspect of the present invention relates to the following electron transport material: it uses the above-mentioned metal complex, can be formed by a wet method in the manufacture of an organic electroluminescent element with a multilayer structure, and has excellent electron injection properties, electron transport properties and durability.

[0069] <9> An electron transport material for an organic electroluminescent element, comprising <1> ~ <7> The metal complex according to any one of items.

[0070] <10> According to the <9> The electron transport material described above, wherein the electron transport material further contains a dopant.

[0071] <11> According to the <10> The electron transport material described above, wherein the dopant contains a metal alkoxide represented by the following formula (7a) and / or the following formula (7b).

[0072] [Chemical formula 12]

[0073] R H1 -OM 1 (7a)

[0074] R H1 -OM 2 -OR H2 (7b)

[0075] In formula (7a) and formula (7b), RH1 , R H2 Each independently represents an alkyl group, and M 1 Alkali metal, M 2 It is an alkaline earth metal.

[0076] <12> According to the <10> or <11> The electron transport material described above, wherein the dopant contains one or more selected from the group consisting of alkali metal complexes of hydroxyquinoline, alkali metal complexes of pyridylphenolate, alkali metal complexes of bipyridylphenolate, and alkali metal complexes of isoquinolylphenolate.

[0077] <13> According to the <10> ~ <12> The electron transport material according to any one of the preceding claims, wherein the dopant contains at least one selected from the group consisting of alkali metal hydroxides, alkali metal halides, alkali metal carbonates, alkali metal bicarbonates, alkali metal organic acid salts having 1 to 9 carbon atoms, alkaline earth metal hydroxides, alkaline earth metal halides, alkaline earth metal carbonates, alkaline earth metal bicarbonates, and alkaline earth metal organic acid salts having 1 to 9 carbon atoms.

[0078] <14> According to the <9> ~ <13> The electron transport material according to any one of claims 1 to 5, wherein the electron transport material further contains a ligand constituting the metal complex.

[0079] Next, according to the above-mentioned object, a fourth aspect of the present invention relates to a liquid material containing the above-mentioned electron transport material and a solvent, and used for constructing an electron transport layer of the following organic electroluminescent element.

[0080] <15> A liquid material containing the <9> ~ <14> The liquid material of any one of the electron transport materials and the protic polar solvent is used to construct the electron transport layer of the organic electroluminescent element.

[0081] <16> According to the <15> The liquid material described above, wherein the protic polar solvent is an alcohol solvent having 1 to 12 carbon atoms.

[0082] <17> According to the <16> The liquid material described above, wherein the alcohol solvent having 1 to 12 carbon atoms is a monovalent or divalent alcohol.

[0083] <18> According to the <15> ~ <17> The liquid material according to any one of the preceding claims, wherein the liquid material contains 0.01 to 10% by mass of the <1> ~ <7> The metal complex according to any one of items.

[0084] Furthermore, according to the above-mentioned object, other aspects of the present invention relate to the following inventions.

[0085] <19> An organic electroluminescent element comprising <9> ~ <14> An electron transport layer of the electron transport material according to any one of claims.

[0086] <20> A method for manufacturing an organic electroluminescent element, comprising: <15> ~ <18> A process for constructing an electron transport layer of an organic electroluminescent element using the liquid material described in any one of claims 1 to 4 by a wet method.

[0087] Effects of the Invention

[0088] According to the present invention, a novel alkali metal complex and alkaline earth metal complex having both electron transport and alcohol solubility can be provided. In addition, the present invention also provides a coordination compound constituting the alkali metal complex and the alkaline earth metal complex. In addition, an electron transport material and an organic electroluminescent element using the electron transport material are also provided, wherein the electron transport material uses the metal complex and can be formed by a wet method in the manufacture of an organic electroluminescent element having a multilayer structure and has excellent electron injection characteristics, electron transport characteristics, and durability.

[0089] The electron transport material including the metal complex of the present invention can have both high electron transport property and high electron injection property, and is suitable for use as an electron transport material for an organic electroluminescent element.

[0090] By using the present invention, it is possible to provide an organic electroluminescent element which is highly productive and can be manufactured at low cost, has excellent luminous efficiency, and has high durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Figure 1 It is a diagram schematically showing a cross-sectional view of an organic electroluminescent element.

[0092] Figure 2 It is a diagram showing the NMR spectrum of the metal complex (L101-Cs) of the present invention and its ligand (L101).

[0093] Figure 3 It is a diagram showing the NMR spectrum of the metal complex (L301-Cs) of the present invention and its ligand (L301).

[0094] Figure 4 It is a diagram showing the NMR spectrum of the metal complex (L302-Cs) of the present invention and its ligand (L302). DETAILED DESCRIPTION

[0095] Next, the embodiment of the present invention will be described in detail to facilitate understanding of the present invention. The description of the constituent elements described below is an example (representative example) of the embodiment of the present invention, and the present invention is not limited to the following contents as long as the gist thereof is not changed. In addition, when the expression "to" is used in this specification, it is used as an expression containing the numerical values ​​before and after it.

[0096] [1] Metal complexes

[0097] The metal complex according to the first embodiment of the present invention (hereinafter sometimes referred to as "the metal complex of the present invention") is a metal complex represented by any one of the following formulae (1) to (3) containing at least one phenanthroline group and a nitrogen-containing condensed ring.

[0098] [Chemical formula 13]

[0099]

[0100] In formulas (1) to (3), R A1 ~R A9 , R C1 ~R C8 , R E1 ~R E6 Each is independently a single bond, an alkylene group, an arylene group, a heteroarylene group or a group represented by the following formula (4):

[0101] [Chemical formula 14]

[0102] -R P1 -P(=O)R P2 -R P3 - (4)

[0103] (In formula (4), R P1 , R P3 are independently a single bond, an alkylene group, an arylene group, or a heteroarylene group, and R P2 is alkyl, aryl or heteroaryl. ).

[0104] R B1 ~R B9 , R D1 ~R D8 , R F1 ~R F6 are each independently a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an amino group, a cyano group, a halogen atom or a hydroxyl group,

[0105] Selected from R B1 ~R B9 At least one of the group consisting of is a phenanthroline group, selected from R D1 ~R D8 At least one of the groups consisting of is a phenanthroline group, selected from RF1 ~R F6 One or more of the groups formed is a phenanthroline group.

[0106] M is an alkali metal or an alkaline earth metal,

[0107] Z is 1 or 2,

[0108] X is O or S.

[0109] The metal complex of the present invention contains at least one phenanthroline group and a nitrogen-containing fused ring. The basic skeleton of formula (1) is a benzimidazole complex. In formula (2), X is O or S, and the basic skeleton when X is O is a benzoxazole complex, and the basic skeleton when X is S is a benzothiazole complex. In formula (3), X is O or S, and the basic skeleton when X is O is a benzofuran pyridine complex, and the basic skeleton when X is S is a benzothiophene pyridine complex.

[0110] The ligands (coordinating compounds) constituting the metal complex of the present invention all have a nitrogen-containing fused ring formed by condensing two or more rings including phenolate (phenolato) and N-containing heterocyclic rings, and are structures in which the nitrogen atom constituting the nitrogen-containing fused ring and the O- ion of the phenolate are coordinated on the metal M. In this way, the part of the ligand coordinated to the metal M forms a rigid skeleton, and it is inferred that the stability of the coordination structure can be improved even in an anionic state, and the durability as an electron transport material described later is also excellent. It can also be inferred that the phenanthroline group can not only improve durability, but also improve electron transport and electron injection.

[0111] Here, in the present application, the nitrogen-containing fused ring is formed by condensing two or more rings, and at least one of the rings constituting the fused ring is an N-containing heterocyclic ring containing a nitrogen atom as a ring constituent element. In the present invention, the basic skeletons of the above formulae (1) to (3) are structures containing a nitrogen-containing fused ring.

[0112] In this application, a single bond indicates a direct connection. For example, R A1 When it is a single bond, it means R B1 A structure that is directly connected to the basic skeleton without intervening an alkylene group, an arylene group, a heteroarylene group, or any group of the above formula (4). P1 When it is a single bond, it means that the P atom is directly connected to the basic skeleton without any group of alkylene, arylene or heteroarylene. P4 When it is a single bond, it means a structure in which the P atom is directly connected to the phenanthroline skeleton without any of an alkylene group, an arylene group, and a heteroarylene group.

[0113] In the present application, the alkylene group may be straight chain, branched chain or cyclic. For example, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene, tert-butylene and the like may be cited as the alkylene group.

[0114] In addition, the alkylene group may be unsubstituted or may have a substituent. As the substituent, aryl, heteroaryl, alkoxy, aryloxy, heteroaryloxy, halogen atom, etc. may be listed, preferably phenyl, naphthyl, pyridyl, bipyridyl, phenanthroline, fluorine atom, etc. When there are multiple substituents, they may be the same or different.

[0115] In the present application, the arylene group may be a monocyclic group or a polycyclic group (a ring aggregate formed by connecting two or more monocyclic groups or a condensed ring formed by condensing two or more monocyclic groups). For example, the arylene group includes phenylene, naphthylene, anthrylene, pyrenylene, biphenylene (divalent biphenyl), etc.

[0116] In addition, the arylene group may be unsubstituted or may have a substituent. Examples of the substituent include an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, a halogen atom, and the like, preferably an alkyl group having 1 to 4 carbon atoms, a phenyl group, a naphthyl group, a pyridyl group, a bipyridyl group, a phenanthroline group, and the like. When there are multiple substituents, they may be the same or different.

[0117] In the present application, the heteroarylene group may be monocyclic or polycyclic. For example, the heteroarylene group includes pyridylene, pyrimidylene, triazinylene, quinolylene, imidazolylene, oxazolylene, thiazolylene, carbolinylene, furylene, thienylene, bipyridylene (divalent bipyridylene) and the like.

[0118] In addition, the heteroarylene group may be unsubstituted or may have a substituent. Examples of the substituent include an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, a halogen atom, and the like, preferably an alkyl group having 1 to 4 carbon atoms, a phenyl group, a naphthyl group, a pyridyl group, a bipyridyl group, a phenanthroline group, and the like. When there are multiple substituents, they may be the same or different.

[0119] In the present application, the alkyl group may be straight chain, branched chain or cyclic. Examples of the alkyl group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl or structural isomers thereof.

[0120] In addition, the alkyl group may be unsubstituted or may have a substituent. As the substituent, aryl, heteroaryl, alkoxy, aryloxy, heteroaryloxy, halogen atom, etc. may be listed, preferably phenyl, naphthyl, pyridyl, bipyridyl, phenanthroline, fluorine atom, etc. When there are multiple substituents, they may be the same or different.

[0121] In the present application, the aryl group may be a monocyclic group or a polycyclic group. For example, examples of the aryl group include phenyl, biphenyl, naphthyl, anthracenyl, pyrenyl, and the like.

[0122] In the present application, the aryl group may be unsubstituted or may have a substituent. As the substituent, there may be listed: an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, a halogen atom, etc., preferably an alkyl group having 1 to 4 carbon atoms, a phenyl group, a naphthyl group, a pyridyl group, a bipyridyl group, a phenanthroline group, etc. When there are multiple substituents, they may be the same or different.

[0123] In the present application, heteroaryl can be monocyclic or polycyclic. At least one of the substituents selected as the metal complex of the present invention is one of heteroaryl, i.e., phenanthroline (phenanthroline). In addition, the metal complex of the present invention can also have heteroaryl other than phenanthroline, for example, as heteroaryl, can be listed: pyridyl, bipyridyl, pyrimidyl, triazine, quinolyl, imidazolyl, oxazolyl, thiazolyl, carbolinyl, furyl, thienyl etc.

[0124] In addition, the heteroaryl group may be unsubstituted or may have a substituent. Examples of the substituent include an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, a halogen atom, and the like, preferably an alkyl group having 1 to 4 carbon atoms, a phenyl group, a naphthyl group, a pyridyl group, a bipyridyl group, a phenanthroline group, and the like. When there are multiple substituents, they may be the same or different.

[0125] In the present application, an alkoxy group is a structure in which an alkyl group is bonded to an oxygen atom, and the alkyl group bonded to the oxygen atom may be a straight chain, a branched chain, or a cyclic chain. For example, the alkoxy group may include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, or a structural isomer thereof.

[0126] In addition, the alkoxy group may be unsubstituted or may have a substituent. As the substituent, aryl, heteroaryl, alkoxy, aryloxy, heteroaryloxy, halogen atom, etc. may be listed, preferably phenyl, naphthyl, pyridyl, bipyridyl, phenanthroline. When there are multiple substituents, they may be the same or different.

[0127] In the present application, an aryloxy group is a structure in which an aryl group is bonded to an oxygen atom, and the aryl group bonded to the oxygen atom may be monocyclic or polycyclic. For example, examples of the aryloxy group include phenyloxy (phenoxy), naphthyloxy, anthryloxy, pyreneoxy, and the like.

[0128] In addition, the aryloxy group may be unsubstituted or may have a substituent. Examples of the substituent include an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, a halogen atom, and the like, preferably an alkyl group having 1 to 4 carbon atoms, a phenyl group, a naphthyl group, a pyridyl group, a bipyridyl group, a phenanthroline group, and the like. When there are multiple substituents, they may be the same or different.

[0129] In the present application, heteroaryloxy is a structure in which a heteroaryl group is bonded to an oxygen atom, and the heteroaryl group bonded to the oxygen atom may be a monocyclic or polycyclic group. For example, heteroaryloxy includes pyridyloxy, pyrimidyloxy, triazineoxy, quinolyloxy, imidazolyloxy, oxazolyloxy, thiazolyloxy, phenanthrolineoxy, carbolineoxy, furanyloxy, thienyloxy, etc.

[0130] In addition, the heteroaryloxy group may be unsubstituted or may have a substituent. Examples of the substituent include an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, a halogen atom, and the like, preferably an alkyl group having 1 to 4 carbon atoms, a phenyl group, a naphthyl group, a pyridyl group, a bipyridyl group, a phenanthroline group, and the like. When there are multiple substituents, they may be the same or different.

[0131] In the present application, amino may be unsubstituted or may have a substituent. Examples of the substituent include alkyl, aryl, heteroaryl, alkoxy, aryloxy, heteroaryloxy, etc., preferably phenyl and pyridyl. When there are multiple substituents, they may be the same or different.

[0132] In the present application, examples of the halogen atom include a fluorine atom (F), a chlorine atom (Cl), a bromine atom (Br), an iodine atom (I) and the like.

[0133] Next, the metal complexes represented by the above formulae (1) to (3) will be described.

[0134] In the above formulas (1) to (3), R A1 ~R A9 , R C1 ~R C8 , R E1 ~R E6 are independently a single bond, an alkylene group, an arylene group, a heteroarylene group or a group represented by the above formula (4) (i.e., -R P1 -P(=O)R P2 -R P3Here, from the viewpoints of structural stability, solubility in polar solvents, ease of synthesis, electron transport or electron injection properties as an electron transport material, etc., R A1 ~R A9 , R C1 ~R C8 , R E1 ~R E6 In the above, the alkylene group preferably has 1 to 4 carbon atoms, the arylene group preferably has 6 to 18 carbon atoms, and the heteroarylene group preferably has 3 to 17 carbon atoms.

[0135] From the perspective of electron transport properties and ease of synthesis as an electron transport material, R A1 ~R A9 , R C1 ~R C8 , R E1 ~R E6 Preferably, each independently represents a single bond, an alkylene group having 1 to 4 carbon atoms, an arylene group having 6 to 18 carbon atoms, a heteroarylene group having 3 to 17 carbon atoms, or a group represented by the above formula (4), and more preferably represents a single bond, an alkylene group having 1 to 4 carbon atoms, a phenylene group, a naphthylene group, a pyridylene group, a bipyridylene group, a pyrimidylene group, or a group represented by the above formula (4). In addition, they may also have a substituent. For example, in order to improve solubility, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms may be further introduced.

[0136] The above formula (4) (i.e., -R P1 -P(=O)R P2 -R P3 -) P1 , R P3 are independently a single bond, an alkylene group, an arylene group or a heteroarylene group. P1 is a group bonded to the basic skeleton of the metal complex represented by the above formula (1) to the above formula (3), R P3 is with R B1 etc., R D1 etc., R F1 In addition, R in the above formula (4) P2 is an alkyl group, an aryl group or a heteroaryl group. P1 , R P2 , R P3 These groups represented may be unsubstituted or may have a substituent.

[0137] R A1 ~R A3 , R A5 ~R A9 , R C1 ~R C8 , R E1~R E6 In the above formula (4), R P1 , R P3 Preferably, each independently represents a single bond, an alkylene group having 1 to 4 carbon atoms, an arylene group having 6 to 18 carbon atoms, or a heteroarylene group having 3 to 17 carbon atoms. From the viewpoint of electron transport properties as an electron transport material, a single bond, an arylene group having 6 to 18 carbon atoms, or a heteroarylene group having 3 to 17 carbon atoms is preferred, a single bond or an arylene group having 6 to 18 carbon atoms is more preferred, and a single bond or a phenylene group is further preferred.

[0138] In addition, R A1 ~R A3 , R A5 ~R A9 , R C1 ~R C8 , R E1 ~R E6 In the above formula (4), R P2 It is preferably an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a heteroaryl group having 3 to 17 carbon atoms. From the viewpoint of electron transport properties as an electron transport material, an aryl group having 6 to 18 carbon atoms or a heteroaryl group having 3 to 17 carbon atoms is preferred, an aryl group having 6 to 18 carbon atoms is more preferred, and a phenyl group is further preferred.

[0139] For example, R A1 ~R A3 , R A5 ~R A9 , R C1 ~R C8 , R E1 ~R E6 In the above formula (4), the group represented by the formula (4) includes: "-C6H4-P(=O)C6H5-(R P1 is phenylene, R P2 is phenyl, R P3 is a single bond", "-P(=O)C6H5-(R P1 , R P3 is a single bond, R P2 is phenyl)" etc.

[0140] R A4 In the above formula (4), R P1 It is preferably an alkylene group having 1 to 4 carbon atoms, an arylene group having 6 to 18 carbon atoms, or a heteroarylene group having 3 to 17 carbon atoms. From the viewpoint of electron transport properties as an electron transport material, an arylene group having 6 to 18 carbon atoms or a heteroarylene group having 3 to 17 carbon atoms is preferred, an arylene group having 6 to 18 carbon atoms is more preferred, and a phenylene group is further preferred.

[0141] In addition, R A4In the above formula (4), R P2 Preferred are alkyl groups having 1 to 4 carbon atoms, aryl groups having 6 to 18 carbon atoms, or heteroaryl groups having 3 to 17 carbon atoms. From the viewpoint of durability, aryl groups having 6 to 18 carbon atoms or heteroaryl groups having 3 to 17 carbon atoms are preferred, aryl groups having 6 to 18 carbon atoms are more preferred, and phenyl groups are further preferred.

[0142] In addition, R A4 In the above formula (4), R P3 Preferred are single bonds, alkylene groups having 1 to 4 carbon atoms, arylene groups having 6 to 18 carbon atoms, or heteroarylene groups having 3 to 17 carbon atoms. From the viewpoint of electron transport properties as an electron transport material, preferred are single bonds, arylene groups having 6 to 18 carbon atoms, or heteroarylene groups having 3 to 17 carbon atoms, more preferred are single bonds or arylene groups having 6 to 18 carbon atoms, and still more preferred are single bonds or phenylene groups.

[0143] For example, R A4 In the above formula (4), the group represented by the formula (4) includes: "-C6H4-P(=O)C6H5-(R P1 is phenylene, R P2 is phenyl, R P3 is a single key)" etc.

[0144] In the above formulas (1) to (3), R B1 ~R B9 , R D1 ~R D8 , R F1 ~R F6 are independently a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an amino group, a cyano group, a halogen atom or a hydroxyl group. B1 ~R B9 At least one of the group consisting of is a phenanthroline group, selected from R D1 ~R D8 At least one of the group consisting of is a phenanthroline group, selected from R F1 ~R F6 Here, from the viewpoints of structural stability, solubility in polar solvents, ease of synthesis, etc., at least one of the groups consisting of R B1 ~R B9 , R D1 ~R D8 , R F1 ~R F6 In the above, the number of carbon atoms of the alkyl group and the alkoxy group is preferably 1 to 4, the number of carbon atoms of the aryl group and the aryloxy group is preferably 6 to 18, and the number of carbon atoms of the heteroaryl group and the heteroaryloxy group is preferably 3 to 17. Furthermore, these may have a substituent.

[0145] For example, R B1 ~R B9 , R D1 ~R D8 , R F1 ~R F6 Each of them independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 18 carbon atoms, a heteroaryl group having 3 to 17 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. B1 ~R B9 , R D1 ~R D8 , R F1 ~R F6 Each of them independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, a pyridyl group, a bipyridyl group, a pyrimidyl group, a triazine group, a phenanthroline group, a carboline group, or an alkoxy group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a n-butyl group, a sec-butyl group, an isobutyl group, and a tert-butyl group, and examples of the alkoxy group having 1 to 4 carbon atoms include the alkoxy groups corresponding to the alkyl group having 1 to 4 carbon atoms.

[0146] In addition, from the viewpoint of electron transport property and durability as an electron transport material, R B1 ~R B9 At least one of the group consisting of R D1 ~R D8 At least one of the group consisting of R F1 ~R F6 At least one of the group consisting of can be independently an aryl group, a heteroaryl group, an aryloxy group or a heteroaryloxy group. In addition, from the viewpoint of the band gap as an electron transport material, the adjustment of the electron conduction level, the luminous efficiency and the heat resistance, the selected R B1 ~R B9 At least one of the group consisting of R D1 ~R D8 At least one of the group consisting of R F1 ~R F6 At least one of the group consisting of these groups may be independently an alkyl group, an alkoxy group, an amino group, a cyano group, a halogen atom or a hydroxyl group.

[0147] For example, R B1 ~R B9 , R D1 ~R D8 , R F1 ~R F6 They may each independently be a hydrogen atom, an aryl group having 6 to 18 carbon atoms, or a heteroaryl group having 3 to 17 carbon atoms. B1 ~R B9 , RD1 ~R D8 , R F1 ~R F6 Each of them can be independently a hydrogen atom, a phenyl group, a biphenyl group, a naphthyl group, a pyridyl group, a bipyridyl group, a pyrimidyl group, a triazine group, a phenanthroline group or a carboline group. B1 ~R B9 , R D1 ~R D8 , R F1 ~R F6 are each independently a hydrogen atom or a phenanthroline group.

[0148] In addition, as described above, the metal complex of the present invention has at least one phenanthroline group. B1 ~R B9 At least one of the group consisting of is a phenanthroline group. D1 ~R D8 At least one of the group consisting of is a phenanthroline group. F1 ~R F6 At least one of the composed groups is a phenanthroline group.

[0149] In the above formula (1), preferably R B1 ~R B9 1 to 4 of the group are phenanthroline groups, more preferably 1 to 3 are phenanthroline groups, and further preferably 1 or 2 are phenanthroline groups. The phenanthroline group may further have a phenanthroline group as a substituent, but the number of phenanthroline groups in one ligand is preferably 1 to 4, more preferably 1 to 3, and further preferably 1 or 2. When the number of phenanthroline groups is too large, there is a tendency that the solubility in the solvent is reduced, the structure is unstable, the durability as an electron transport material is reduced, and the synthesis is difficult.

[0150] In the above formula (2), preferably selected from R D1 ~R D8 1 to 3 of the group are phenanthroline groups, and more preferably 1 or 2 are phenanthroline groups. The phenanthroline group may further have a phenanthroline group as a substituent, but the number of phenanthroline groups in one ligand is preferably 1 to 4, more preferably 1 to 3, and further preferably 1 or 2. When the number of phenanthroline groups is too large, there is a tendency that the solubility in the solvent is reduced, the structure is unstable, the durability as an electron transport material is reduced, and the synthesis is difficult.

[0151] In the above formula (3), preferably selected from R F1 ~R F61 to 3 of the group are phenanthroline groups, and more preferably 1 or 2 are phenanthroline groups. The phenanthroline group may further have a phenanthroline group as a substituent, but the number of phenanthroline groups in one ligand is preferably 1 to 4, more preferably 1 to 3, and further preferably 1 or 2. When the number of phenanthroline groups is too large, there is a tendency that the solubility in the solvent is reduced, the structure is unstable, the durability as an electron transport material is reduced, and the synthesis is difficult.

[0152] Here, the phenanthroline group is preferably selected from 1,10-phenanthroline groups represented by the following formula (5a) to the following formula (5d). When the metal complex of the present invention has two or more phenanthroline groups, the phenanthroline groups may be the same or different, and are preferably independently selected from the groups represented by the following formula (5a) to the following formula (5d). Among them, the following formula (5a) or the following formula (5c) is preferred.

[0153] [Chemical formula 15]

[0154]

[0155] In the above formulas (5a) to (5d), R G2 ~R G9 Each independently represents a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an amino group, a cyano group, a halogen atom, a hydroxyl group or a group represented by the following formula (6).

[0156] [Chemical formula 16]

[0157] -R P4 -P(=O)R P5 -R P6 (6)

[0158] In formula (6), R P4 is a single bond, an alkylene group, an arylene group or a heteroarylene group, R P5 , R P6 are independently alkyl, aryl, or heteroaryl. P4 , R P5 , R P6 These groups represented may be unsubstituted or may have a substituent.

[0159] Here, R in the above formula (5a) to the above formula (5d) G2 ~R G9 In the above, from the viewpoints of structural stability, solubility in polar solvents, ease of synthesis, etc., the number of carbon atoms of the alkyl group and the alkoxy group is preferably 1 to 4, the number of carbon atoms of the aryl group and the aryloxy group is preferably 6 to 18, and the number of carbon atoms of the heteroaryl group and the heteroaryloxy group is preferably 3 to 17.

[0160] For example, R G2 ~R G9Each of them can be independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 18 carbon atoms, a heteroaryl group having 3 to 17 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a group represented by the above formula (6). G2 ~R G9 Each of them independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, a pyridyl group, a bipyridyl group, a pyrimidyl group, a triazine group, a phenanthroline group, a carboline group, an alkoxy group having 1 to 4 carbon atoms, or a group represented by the above formula (6). In addition, they may have a substituent.

[0161] From the viewpoint of electron transport properties and durability as an electron transport material, R G2 ~R G9 At least one of the group consisting of may be an aryl group, a heteroaryl group, an aryloxy group, or a heteroaryloxy group. G9 , R in the above formulas (5b) to (5d) G2 and / or R G9 The introduction of a substituent (alkyl, aryl, heteroaryl, alkoxy, aryloxy, heteroaryloxy, amino, cyano, halogen atom, hydroxyl or a group represented by the above formula (6)) can improve the durability of the electron transport material. In addition, from the viewpoint of adjusting the band gap or electron conduction level of the electron transport material, luminous efficiency and heat resistance, the selected R G2 ~R G9 At least one of the group consisting of these groups may be an alkyl group, an alkoxy group, an amino group, a cyano group, a halogen atom, a hydroxyl group or a group represented by the above formula (6).

[0162] For example, R G2 ~R G9 R may be each independently a hydrogen atom, an aryl group having 6 to 18 carbon atoms, a heteroaryl group having 3 to 17 carbon atoms, or a group represented by the above formula (6). G2 ~R G9 Each of them can be independently a hydrogen atom, a phenyl group, a biphenyl group, a naphthyl group, a pyridyl group, a bipyridyl group, a pyrimidyl group, a triazine group, a phenanthroline group, a carboline group or a group represented by the above formula (6). G2 ~R G9 Each of them may be independently a hydrogen atom or a group represented by the above formula (6). G2 ~R G9 Each of them independently may be a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a group represented by the above formula (6).

[0163] As the group represented by the above formula (6), R P4Preferably a single bond, an alkylene group having 1 to 4 carbon atoms, an arylene group having 6 to 18 carbon atoms, or a heteroarylene group having 3 to 17 carbon atoms. In addition, they may also have substituents. For example, R P4 may be a single bond, an alkylene group having 1 to 4 carbon atoms, a phenylene group, a naphthylene group, a pyridyl group, a bipyridyl group, or a pyrimidinyl group. Additionally, R P4 may also be a single bond or a phenylene group.

[0164] Additionally, R P5 , R P6 are preferably each independently an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a heteroaryl group having 3 to 17 carbon atoms. For example, more preferably, R P5 , R P6 are each independently an alkyl group having 1 to 4 carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, a pyridyl group, a bipyridyl group, or a phenanthroline group.

[0165] Specifically, as the group represented by the above formula (6), examples include: "-P(=O)(C6H5)2 (R P4 is a single bond, R P5 and R P6 are phenyl groups)".

[0166] From the viewpoints of structural stability, solubility in polar solvents, ease of synthesis, etc., the phenanthroline groups represented by the above formulas (5a) to (5d) are preferably selected such that 2 to 7 of those composed of R G2 to R G9 are hydrogen atoms, more preferably 4 to 7 are hydrogen atoms, and further preferably 6 or 7 are hydrogen atoms. For example, R G3 and R G8 can be hydrogen atoms. Additionally, R G3 , R G4 , R G7 and R G8 can be hydrogen atoms. Additionally, R G3 to R G8 can be hydrogen atoms.

[0167] In the metal complexes represented by the above formulas (1) to (3), M represents an alkali metal or an alkaline earth metal. Examples of the alkali metal include: Li, Na, K, Rb, Cs, etc., and examples of the alkaline earth metal include: Be, Mg, Ca, Sr, Ba, etc.

[0168] As the metal complex for an electron transport material described later, an alkali metal is more preferred. Among them, from the viewpoints of both electron injection property and alcohol solubility, the larger the atomic number in the order of Li < Na < K < Rb < Cs, the better, and Rb or Cs is more suitable for use. Additionally, as the alkaline earth metal, Ba is suitable for use.

[0169] In the metal complexes represented by the above formulae (1) to (3), Z represents an integer of 1 or 2. That is, Z is 1 when M is an alkali metal, and Z is 2 when M is an alkaline earth metal.

[0170] Next, the metal complexes represented by the above formulae (1) to (3) of the present invention will be described in more detail.

[0171] (A) Metal complex represented by formula (1)

[0172] Examples of the metal complex represented by formula (1) of the present invention include: B1 , R B3 , R B4 and R B6 A complex in which at least one of the groups is a phenanthroline group.

[0173] For example, the following complexes can be cited: A2 , R A5 , R A7 ~R A9 is a single bond, R B2 , R B5 , R B7 ~R B9 is a hydrogen atom, R A1 , R A3 , R A4 , R A6 are independently a single bond, an alkylene group, an arylene group, a heteroarylene group or a group represented by the above formula (4), R B1 , R B3 , R B4 , R B6 are independently a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an amino group, a halogen atom, a cyano group or a hydroxyl group, R B1 , R B3 , R B4 and R B6 At least one of them is a phenanthroline group.

[0174] In addition, the following complexes can also be cited: A1 , R A2 , R A5 ~R A9 is a single bond, R B1 , R B2 , R B5 ~R B9 is a hydrogen atom, R A3 , R A4 are independently a single bond, an alkylene group, an arylene group, a heteroarylene group or a group represented by the above formula (4), R B3 , R B4are independently a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an amino group, a halogen atom, a cyano group or a hydroxyl group, R B3 , R B4 At least one of them is a phenanthroline group.

[0175] In addition, examples of the metal complex represented by the formula (1) of the present invention include the following complexes: B3 , R B4 and R B7 At least one of the groups is a phenanthroline group.

[0176] For example, the following complexes can be cited: A1 , R A2 , R A5 , R A6 , R A8 , R A9 is a single bond, R B1 , R B2 , R B5 , R B6 , R B8 , R B9 is a hydrogen atom, R A3 , R A4 , R A7 are each independently a single bond, an arylene group having 6 to 18 carbon atoms, a heteroarylene group having 3 to 17 carbon atoms, or a group represented by the general formula (4), R B3 , R B4 , R B7 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 18 carbon atoms, a heteroaryl group having 3 to 17 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and R B3 , R B4 , R B7 At least one of them is a phenanthroline group.

[0177] In addition, the following complexes may also be present: R A1 ~R A9 is a single bond, an arylene group having 6 to 18 carbon atoms, a heteroarylene group having 3 to 17 carbon atoms, or a group represented by the above formula (4), R B1 ~R B3 , R B5 ~R B9 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 18 carbon atoms, a heteroaryl group having 3 to 17 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and R B4 It is a phenanthroline group.

[0178] In addition, the following complexes may also be present: R A1 ~RA9 is a single bond, an arylene group having 6 to 18 carbon atoms, a heteroarylene group having 3 to 17 carbon atoms, or a group represented by the above formula (4), R B1 ~R B2 , R B4 ~R B9 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 18 carbon atoms, a heteroaryl group having 3 to 17 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and R B3 It is a phenanthroline group.

[0179] Specifically, the compounds represented by the following L101-M to L108-M can be exemplified. In addition, M represents an alkali metal or an alkaline earth metal. In addition, the following compounds are only examples, and the metal complex of the present invention is not limited to these.

[0180] [Chemical formula 17]

[0181]

[0182] [Chemical formula 18]

[0183]

[0184] [Chemical formula 19]

[0185]

[0186] (B) Metal complex represented by formula (2)

[0187] Examples of the metal complex represented by formula (2) of the present invention include: D1 , R D3 and R D5 A complex in which at least one of the groups is a phenanthroline group.

[0188] For example, the following complexes can be cited: C2 , R C4 , R C6 ~R C8 is a single bond, R D2 , R D4 , R D6 ~R D8 is a hydrogen atom, R C1 , R C3 , R C5 are independently a single bond, an alkylene group, an arylene group, a heteroarylene group or a group represented by the above formula (4), R D1 , R D3 , R D5are independently a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an amino group, a halogen atom, a cyano group or a hydroxyl group, R D1 , R D3 and R D5 At least one of them is a phenanthroline group.

[0189] In addition, the following complexes can also be cited: C1 , R C2 , R C4 , R C6 ~R C8 is a single bond, R D1 , R D2 , R D4 , R D6 ~R D8 is a hydrogen atom, R C3 , R C5 are independently a single bond, an alkylene group, an arylene group, a heteroarylene group or a group represented by the above formula (4), R D3 , R D5 are independently a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an amino group, a halogen atom, a cyano group or a hydroxyl group, R D3 , R D5 At least one of them is a phenanthroline group.

[0190] In addition, examples of the metal complex represented by the formula (2) of the present invention include the following complexes: D3 , R D5 and R D7 At least one of the groups is a phenanthroline group.

[0191] For example, the following complexes can also be cited: C1 , R C2 , R C4 , R C6 , R C8 is a single bond, R D1 , R D2 , R D4 , R D6 , R D8 is a hydrogen atom, R C3 , R C5 , R C7 are each independently a single bond, an arylene group having 6 to 18 carbon atoms, a heteroarylene group having 3 to 17 carbon atoms, or a group represented by the general formula (4), R D3 , R D5 , R D7 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 18 carbon atoms, a heteroaryl group having 3 to 17 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and RD3 , R D5 , R D7 At least one of them is a phenanthroline group.

[0192] In addition, the following complexes may also be present: R C1 ~R C8 is a single bond, an arylene group having 6 to 18 carbon atoms, a heteroarylene group having 3 to 17 carbon atoms, or a group represented by the general formula (4), R D1 ~R D2 , R D4 ~R B8 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 18 carbon atoms, a heteroaryl group having 3 to 17 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and R D3 It is a phenanthroline group.

[0193] In addition, the following complexes may also be present: R C1 ~R C8 is a single bond, an arylene group having 6 to 18 carbon atoms, a heteroarylene group having 3 to 17 carbon atoms, or a group represented by the general formula (4), R D1 ~R D4 , R D6 ~R D8 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 18 carbon atoms, a heteroaryl group having 3 to 17 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and R D5 It is a phenanthroline group.

[0194] Specifically, the compounds represented by the following L201-M to L212-M can be exemplified. In addition, M represents an alkali metal or an alkaline earth metal. In addition, the following compounds are only examples, and the metal complex of the present invention is not limited to these.

[0195] [Chemical formula 20]

[0196]

[0197] [Chemical formula 21]

[0198]

[0199] [Chemical formula 22]

[0200]

[0201] [Chemical formula 23]

[0202]

[0203] [Chemical formula 24]

[0204]

[0205] (C) Metal complex represented by formula (3)

[0206] Examples of the metal complex represented by formula (3) of the present invention include: F1 , R F3 , R F5 A complex in which at least one of the groups is a phenanthroline group.

[0207] For example, the following complexes can be cited: E2 , R E4 , R E6 is a single bond, R F2 , R F4 , R F6 is a hydrogen atom, R E1 , R E3 , R E5 are independently a single bond, an alkylene group, an arylene group, a heteroarylene group or a group represented by the above formula (4), R F1 , R F3 , R F5 are independently a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an amino group, a halogen atom, a cyano group or a hydroxyl group, R F1 , R F3 and R F5 At least one of them is a phenanthroline group.

[0208] In addition, the following complexes can be cited: R E1 , R E2 , R E4 , R E6 is a single bond, R F1 , R F2 , R F4 , R F6 is a hydrogen atom, R E3 , R E5 are independently a single bond, an alkylene group, an arylene group, a heteroarylene group or a group represented by the above formula (4), R F3 , R F5 are independently a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an amino group, a halogen atom, a cyano group or a hydroxyl group, R F3 , R F5 At least one of them is a phenanthroline group.

[0209] In addition, the following complex may be used: R E1 ~R E6 is a single bond, an arylene group having 6 to 18 carbon atoms, a heteroarylene group having 3 to 17 carbon atoms, or a group represented by the above formula (4), R F1 ~RF2 , R F4 ~R F6 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 18 carbon atoms, a heteroaryl group having 3 to 17 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and R F3 It is a phenanthroline group.

[0210] In addition, the following complexes may also be present: R E1 ~R E6 is a single bond, an arylene group having 6 to 18 carbon atoms, a heteroarylene group having 3 to 17 carbon atoms, or a group represented by the general formula (4), R F1 ~R F4 , R F6 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 18 carbon atoms, a heteroaryl group having 3 to 17 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and R F5 It is a phenanthroline group.

[0211] Specifically, the compounds represented by the following L301-M to L320-M can be exemplified. In addition, M represents an alkali metal or an alkaline earth metal. In addition, the following compounds are only examples, and the metal complex of the present invention is not limited to these.

[0212] [Chemical formula 25]

[0213]

[0214] [Chemical formula 26]

[0215]

[0216] [Chemical formula 27]

[0217]

[0218] [Chemical formula 28]

[0219]

[0220] [Chemical formula 29]

[0221]

[0222] [Chemical formula 30]

[0223]

[0224] [Chemical formula 31]

[0225]

[0226] [Chemical formula 32]

[0227]

[0228] (Manufacturing method)

[0229] The metal complex having the structure represented by the above general formulae (1) to (3) of the present invention can be synthesized, for example, by reacting a compound (ligand) represented by the following formulae (1a) to (3a) with an alkali metal compound or alkaline earth metal compound as a metal ion source.

[0230] [Chemical formula 33]

[0231]

[0232] In the above formulas (1a) to (3a), R A1 ~R A9 , R C1 ~R C8 , R E1 ~R E6 , R B1 ~R B9 , R D1 ~R D8 , R F1 ~R F6 , X have the same meanings as in the above formula (1) to the above formula (3), and the preferred embodiments are also the same.

[0233] For example, when an alkali metal hydroxide or an alkaline earth metal hydroxide is used as a metal ion source, the metal complex of the present invention can be obtained by the following reaction.

[0234] [Chemical formula 34]

[0235]

[0236] [Chemical formula 35]

[0237]

[0238] [Chemical formula 36]

[0239]

[0240] The molar ratio of the ligand to the metal ion source is appropriately adjusted according to the type of alkali metal compound or alkaline earth metal compound used and the valence of the central metal of the synthesized metal complex. When the ligand reacts with the alkali metal compound, the reaction can be carried out at a molar ratio of ligand: alkali metal ion in the alkali metal compound = 1:0.5 to 1:2 or 1:0.5 to 1:1.5. In addition, when the ligand reacts with the alkaline earth metal compound, the reaction can be carried out at a molar ratio of ligand: alkaline earth metal ion in the alkaline earth metal compound = 1:0.25 to 1:1 or 1:0.25 to 1:0.8.

[0241] The reaction temperature or reaction time can be appropriately adjusted according to the structure of the synthesized metal complex, the type of metal ion source, etc. For example, in the presence of a solvent, the ligand and the metal ion source are reacted at 20 to 30 ° C for 0.5 to 25 hours to synthesize the metal complex of the present invention. Appropriate purification can also be performed after the reaction of the ligand and the metal ion source. In addition, when the purity of the ligand or metal ion source used is very high, it is also possible not to purify after the reaction, and the solid obtained by removing the solvent can be directly used for the purposes of the electron transport material described later. According to the molar ratio of the ligand to the metal ion source, the solid obtained by removing the solvent sometimes contains unreacted ligands and metal ion sources in addition to the metal complex of the present invention, but since the unreacted ligands and metal ions may contribute to the improvement of the electron transport properties of the electron transport material, they can also be used in a state containing them. In addition, it can also contain a substance that forms a coordination bond with a heteroatom such as a nitrogen atom of other ligands other than the ligand with an oxygen atom to which the metal ion is bonded. In addition, it is also possible to contain a substance in which a metal ion of a metal ion source forms a coordination bond with a nitrogen atom of a phenanthroline group constituting a ligand. That is, the unreacted ligand and metal ion source generated when synthesizing the metal complex of the present invention are not all in a free state, and a part of them may become a coordination bond state as described above, or be locally present near the metal complex.

[0242] [2] Coordination compounds

[0243] The coordination compound described in the second embodiment of the present invention is a compound represented by the above formula (1a) to the above formula (3a) containing one or more phenanthroline groups and a nitrogen-containing fused ring. The coordination compound can be used to synthesize the metal complex described in the first embodiment of the present invention, and can also be used as a ligand constituting the metal complex.

[0244] [3] Electron transport materials

[0245] The electron transport material described in the third embodiment of the present invention (hereinafter, sometimes referred to as "the electron transport material of the present invention") includes an alkali metal complex or an alkaline earth metal complex represented by the above formula (1) to the above formula (3) described in detail in the above first embodiment. The metal complex represented by the above formula (1) to the above formula (3) tends to have a wide band gap and is suitable as an electron transport material.

[0246] When the structure of "-OM···N≡" of the metal complex of the present invention is used as an electron transport material, it can impart solubility in protic polar solvents such as alcohols described later, and contribute to the improvement of electron injection. In addition, the phenanthroline group helps to improve electron transport and durability. Moreover, the metal complex of the present invention has a low degree of freedom in the ligand part coordinated to the metal M and has a rigid structure, so an electron transport material with better durability and excellent life can be obtained.

[0247] The electron transport material of the present invention preferably contains a dopant in order to improve the electron injection property and the electron transport property. The dopant contained in the electron transport material of the present invention preferably uses a substance having the property of reducing the metal complex of the present invention. For example, a compound containing an alkali metal or an alkaline earth metal can be used.

[0248] One of the substances suitable as the dopant contained in the electron transport material of the present invention is a metal alkoxide. That is, in the electron transport material of the present invention, the dopant preferably contains a metal alkoxide.

[0249] The metal alkoxide may be used in its prepared form, or may be prepared by adding an alkali metal or an alkaline earth metal to any alcohol solvent and reacting the resulting metal alkoxide with the alcohol solvent.

[0250] When the prepared metal alkoxide is used, the compound represented by the following formula (7a) and / or (7b) is more preferably used.

[0251] [Chemical formula 37]

[0252] R H1 -OM 1 7a)

[0253] R H1 -OM 2 -OR H2 (7b)

[0254] In the above formulas (7a) and (7b), R H1 , R H2 Each independently represents an alkyl group, and M 1 Represents alkali metal, M 2 Represents alkaline earth metals.

[0255] Examples of the alkyl group include linear, branched or cyclic alkyl groups having 1 to 10 carbon atoms, preferably 1 to 7 carbon atoms. Specifically, examples include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, 1-methylbutyl, 1-ethylpropyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1-methyl-2-methylpropyl, 2,2-dimethylpropyl, n-hexyl, 2-methylpentyl, 1-methyl-3-methylbutyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, 1-ethylpentyl, n-octyl, 1-methylheptyl, 2-ethylhexyl, n-nonyl, 3,5,5-trimethylhexyl, and n-decyl. Among them, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, and n-hexyl are preferably used.

[0256] These may be used alone or in combination of any two or more in any ratio.

[0257] As M 1 Specific examples include alkali metals such as Li, Na, K, Rb or Cs as M 2 Specific examples include alkaline earth metals such as Be, Mg, Ca, Sr, and Ba. Among them, Li is preferably used from the viewpoint of film forming properties and electron transport properties.

[0258] When an alkali metal or alkaline earth metal is added to an alcohol solvent (alcohol) to prepare a metal alkoxide, the alkali metal or alkaline earth metal is added to the alcohol solvent under an inert gas atmosphere and stirred to dissolve to a predetermined concentration. During the dissolution, cooling or heating may be performed as required. Taking a monohydric alcohol as an example, at this time, the reaction represented by the following reaction formula (8a) or reaction formula (8b) is performed to prepare a solution in which the metal alkoxide is dissolved.

[0259] [Chemical formula 38]

[0260] R 1 -OH+M 1 →R 1 -OM 1 +1 / 2H2 (8a)

[0261] 2R 1 -OH+M 2 →R 1 -OM 2 -OR 1 +H2 (8b)

[0262] Alcohol is a general term for compounds having a hydroxyl group (OH group). In the above reaction formula (8a) or the above reaction formula (8b), R 1 Corresponding to the part obtained by removing the hydroxyl group of the corresponding alcohol solvent, M 1Represents alkali metal, M 2 Represents alkaline earth metals.

[0263] As the solvent used in the preparation of the metal alkoxide, the solvent used in the liquid material described below can be used in the same manner. Among them, monohydric alcohols are preferred.

[0264] Specific examples of the metal alkoxide include sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium ethoxide, potassium tert-butoxide, lithium n-butoxide, lithium tert-butoxide, and cesium n-heptanoxide.

[0265] As suitable dopants contained in the electron transport material of the present invention, there can be mentioned: at least one selected from the group consisting of hydroxyquinoline complexes, pyridylphenolate complexes, bipyridylphenolate complexes and isoquinolylphenolate complexes having alkali metals and / or alkaline earth metals. In the electron transport material of the present invention, the dopant preferably contains at least one selected from the group consisting of alkali metal complexes of hydroxyquinoline, alkali metal complexes of pyridylphenolate, alkali metal complexes of bipyridylphenolate and alkali metal complexes of isoquinolylphenolate.

[0266] Specific examples of these hydroxyquinoline complexes or phenolate complexes include 8-hydroxyquinoline lithium, 8-hydroxyquinoline sodium, 8-hydroxyquinoline cesium, 2-(2-pyridyl)phenolate lithium, 2-(2-pyridyl)phenolate sodium, 2-(2,2'-bipyridyl-6-yl)phenolate lithium, and 2-(1-isoquinolyl)phenolate lithium.

[0267] Suitable dopants contained in the electron transport material of the present invention include alkali metal hydroxides, alkali metal salts, alkaline earth metal hydroxides and alkaline earth metal salts. That is, in the electron transport material of the present invention, the dopant preferably contains one or more selected from the group consisting of alkali metal hydroxides, alkali metal halides, alkali metal carbonates, alkali metal bicarbonates, organic acid salts of alkali metals having 1 to 9 carbon atoms, alkaline earth metal hydroxides, alkaline earth metal halides, alkaline earth metal carbonates, alkaline earth metal bicarbonates and organic acid salts of alkaline earth metals having 1 to 9 carbon atoms.

[0268] By including these inorganic compounds or organic acid salts, electron transport properties can be improved and durability can be improved. Since these inorganic compounds or organic acid salts easily dissociate metal ions, liquid materials for manufacturing organic electroluminescent elements with higher efficiency, excellent durability and better productivity can be obtained.

[0269] Specific examples of these inorganic compounds or organic acid salts include: lithium hydroxide, sodium hydroxide, cesium hydroxide, rubidium hydroxide, lithium chloride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, lithium bromide, sodium bromide, potassium bromide, rubidium bromide, cesium bromide, lithium iodide, sodium iodide, potassium iodide, rubidium iodide, cesium iodide, lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, lithium bicarbonate, sodium bicarbonate, potassium bicarbonate, rubidium bicarbonate, cesium bicarbonate, lithium acetate, sodium acetate, potassium acetate, rubidium acetate, cesium acetate, lithium formate, sodium formate, potassium formate, rubidium formate, cesium formate, etc.

[0270] The dopant contained in the electron transport material of the present invention can be used alone or in combination of any two or more compounds. For example, the dopant contained in the electron transport material of the present invention can be a complex dopant such as the above-mentioned metal alkoxide, alkali metal complex of hydroxyquinoline, alkali metal hydroxide, alkali metal salt, alkaline earth metal hydroxide, alkaline earth metal salt, alone or in combination.

[0271] The ratio of the dopant contained in the electron transport material of the present invention can be appropriately adjusted according to the type of the dopant, etc. The dopant contained in the electron transport material of the present invention may be 0.1 to 50 wt %, more preferably 1 to 40 wt % relative to the metal complex of the present invention.

[0272] In addition, the electron transport material of the present invention may contain a ligand constituting the metal complex of the present invention in addition to the metal complex of the present invention. For example, as described above, the solid obtained by the reaction of the ligand and the metal ion source may be used directly as the electron transport material without purification, and may contain unreacted ligands and metal ion sources.

[0273] [4] Liquid materials

[0274] The invention according to the fourth embodiment of the present invention relates to a liquid material containing the electron transport material according to the third embodiment of the present invention and a solvent (hereinafter sometimes referred to as "liquid material of the present invention").

[0275] In the liquid material of the present invention, the solvent is preferably a solvent that is difficult to swell or dissolve the organic light-emitting layer. Thus, when used in the manufacture of an organic electroluminescent element, the organic light-emitting layer film can be prevented from being deteriorated or becoming extremely thin, and as a result, a liquid material for the manufacture of an organic electroluminescent element with higher efficiency, excellent durability, and better productivity can be obtained.

[0276] In the liquid material of the present invention, the solvent is preferably a protic polar solvent. Most of the luminescent materials and hole transport materials are difficult to dissolve in protic polar solvents. Therefore, by using a protic polar solvent, the reduction of efficiency can be prevented. As a result, a liquid material with better productivity used in the manufacture of an organic electroluminescent element with higher efficiency and excellent durability can be obtained. In the liquid material of the present invention, the solvent is preferably an alcohol solvent as a main component. For example, the proportion of the alcohol solvent in the solvent of the liquid material can be listed as: 50% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, 100% by weight, etc.

[0277] As the alcohol solvent, an alcohol having 1 to 12 carbon atoms, preferably an alcohol having 1 to 10 carbon atoms, and more preferably a monovalent or divalent alcohol having 1 to 7 carbon atoms can be used. Among them, a monovalent alcohol is preferably used.

[0278] Specific examples of the alcohol solvent include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentanol, tert-pentanol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 4-methyl-2-pentanol, 2-methyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, 1-nonanol, 3,5,5-trimethyl-1-hexanol, 1-decanol, 1-undecanol, 1-dodecanol, allyl alcohol, propargyl alcohol, benzyl alcohol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 4-Methylcyclohexanol, α-terpineol, rosin alcohol, fusel oil, 1,2-ethanediol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2,3-butylene glycol, 1,5-pentanediol, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, glycerol, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol, 1,2,6-hexanetriol, and 2-methoxyethanol, 2-ethoxyethanol, 2-(methoxyethoxy)ethanol, 2-isopropoxyethanol, 2-butoxyethanol, 2-(isopentyloxy)ethanol, 2-(hexyloxy)ethanol, 2-phenoxyethanol, 2-(benzyloxy)ethanol, Furfuryl alcohol, tetrahydrofurfuryl alcohol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, tetraethylene glycol, polyethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, diacetone alcohol, 2-chloroethanol, 1-chloro-2-propanol, 3-chloro-1,2-propanediol, 1,3-dichloro-2-propanol, 2,2,2-trifluoroethanol, 3-hydroxypropionitrile, acetone cyanohydrin, 2-aminoethanol, 2-(dimethylamino)ethanol, 2-(diethylamino)ethanol, diethanolamine, N-butyldiethanolamine, triethanolamine, triisopropanolamine, 2,2'-thiodiethanol, as well as tetrafluoropropanol, pentafluoropropanol, 2,2, 2-Trifluoroethanol, 2-(perfluorobutyl)ethanol, 3,3,4,4,5,5,6,6,6-nonafluoro-1-hexanol, 2-(perfluorobutyl)ethanol, 3,3,4,4,5,5,6,6,6-nonafluorohexanol, 1,1,2,2-tetrahydroperfluorohexanol, 1H,1H,2H,2H-nonafluoro-1-hexanol, 1H,1H,2H,2H-nonafluoro-n-hexanol, 1H,1H,2H,2H-nonafluorohexanol, 1H,1H,2H,2H-nonafluorohexanol, 1H,1H,2H,2H-perfluorohexane-1-ol, 1H,1H,2H,2H-perfluorohexanol, 3,3,4,4,5,5,6,6,6-nonafluoro-1-hexanol, 2-(perfluorohexyl)ethanol, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol, 2-(perfluorohexyl)ethanol, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanol, 1,1,2,2-tetrahydroperfluorooctanol, 1,1,2,2-tetrahydrotridecafluorooctanol, 1H,1H,2H,2H-perfluoro-1-octanol, 1H,1H,2H,2H-perfluorooctan-1-ol, 1H,1H,2H,2H-perfluorooctanol, 1H,1H,2H,2H-tridecafluoro-n-octanol, 1H,1H,2H,2H-tridecafluorooctanol, 2-(tridecafluorohexyl)ethanol, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol, perfluorohexylethanol, etc.

[0279] Among them, 1-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-methyl-1-butanol, 1-hexanol, 1-heptanol, 1-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methoxyethanol, 2-ethoxyethanol, and 2-(methoxyethoxy)ethanol are more preferably used. They can be used alone or any two or more of them can be mixed in any proportion.

[0280] The alcohols having these carbon numbers have high solubility in the metal complex, metal alkoxide, etc. of the present invention, and as a result, a liquid material for producing an organic electroluminescent element having higher efficiency, excellent durability, and better productivity can be obtained.

[0281] The liquid material of the present invention contains 0.01 to 10% by weight, preferably 0.1 to 5% by weight, of a metal complex having a structure represented by the above formula (1) to the above formula (3). When the content of the metal complex is less than 0.01% by weight, it may be impossible to form a required film thickness on the organic electroluminescent element. On the other hand, when the content of the metal complex exceeds 10% by weight, it becomes difficult to dissolve in a solvent.

[0282] The liquid material of the present invention can be prepared by mixing the metal complex of the present invention and the metal alkoxide, metal ion salt, etc., but it is preferred to mix the first solution containing the metal complex of the present invention with the second solution containing the metal alkoxide, metal ion salt, etc. to prepare the liquid material.

[0283] [5] Organic electroluminescent elements

[0284] Next, an organic electroluminescent element according to a fifth embodiment using the electron transport material (third embodiment) of the present invention will be described.

[0285] The organic electroluminescent element of the present invention may have an electron transport layer containing the electron transport material of the present invention. That is, the organic electroluminescent element of the present invention has an anode, a cathode, and an organic compound layer provided between the anode and the cathode and containing at least a hole transport layer, a light-emitting layer, and an electron transport layer, and the electron transport layer may be an organic electroluminescent element containing the electron transport material of the present invention.

[0286] The method for producing an organic electroluminescent element of the present invention comprises a step of constructing an electron transport layer of the organic electroluminescent element by a wet method using the liquid material of the present invention. This method is particularly suitable for producing the organic electroluminescent element of the present invention.

[0287] like Figure 1 As shown, the organic electroluminescent element 1 of the present invention is an organic electroluminescent element having an anode 3, a cathode 8, and a plurality of organic compound layers stacked between the anode 3 and the cathode 8 (starting from the anode 3 side, the hole injection layer 4, the hole transport layer 5, the light-emitting layer 6, and the electron transport layer 7). The anode 3 is arranged on a transparent substrate 2, and all are sealed with a sealing member 9. The light-emitting layer 6 contains an organic compound insoluble in an alcohol solvent. The electron transport layer 7 formed by contacting the light-emitting layer 6 on the surface opposite to the cathode 8 contains one or more electron transport materials of the present invention that are soluble in an alcohol solvent.

[0288] The substrate 2 is a support of the organic electroluminescent element 1. The organic electroluminescent element 1 described in this embodiment is a structure in which light is extracted from the substrate 2 side (bottom emission type), so the substrate 2 and the anode 3 are respectively composed of substantially transparent (colorless transparent, colored transparent or translucent) materials. As the constituent material of the substrate 2, for example, resin materials such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, cycloolefin polymer, polyamide, polyester sulfone, polymethyl methacrylate, polycarbonate, and polyarylate, glass materials such as quartz glass and soda glass, etc. can be listed, and one or more of them can be used in combination.

[0289] The average thickness of the substrate 2 is not particularly limited, but is preferably about 0.1 to 30 mm, and more preferably about 0.1 to 10 mm. In addition, when the organic electroluminescent element 1 is configured to extract light from the opposite side of the substrate 2 (top emission type), the substrate 2 can use any of a transparent substrate and an opaque substrate. Examples of opaque substrates include substrates made of ceramic materials such as alumina, substrates with oxide films (insulating films) formed on the surface of metal substrates such as stainless steel, and substrates made of resin materials.

[0290] The anode 3 is an electrode for injecting holes into the hole injection layer 4 described later. As the constituent material of the anode 3, it is preferable to use a material having a large work function and excellent conductivity. Examples of the constituent material of the anode 3 include ITO (indium tin oxide), IZO (indium zirconium oxide), In3O3, S n O2, S containing Sb n Oxides such as O2, ZnO containing Al, Au, Pt, Ag, Cu or alloys containing them, etc., one or more of which can be used in combination. The average thickness of the anode 3 is not particularly limited, but is preferably about 10 to 200 nm, more preferably about 50 to 150 nm.

[0291] On the other hand, the cathode 8 is an electrode for injecting electrons into the electron transport layer 7, and is arranged on the opposite side of the light-emitting layer 6 connected to the electron transport layer 7. As the constituent material of the cathode 8, it is preferred to use a material with a small work function. As the constituent material of the cathode 8, for example, Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc, Y, Yb, Ag, Cu, Al, Cs, Rb or alloys containing them, etc., one of which or any two or more combinations thereof (such as a multilayer laminate, etc.) can be used.

[0292] In particular, when an alloy is used as a constituent material of the cathode 8, an alloy containing a stable metal element such as Ag, Al, Cu, etc. is preferably used, and specifically, an alloy such as MgAg, AlLi, CuLi, etc. is preferably used. By using such an alloy as a constituent material of the cathode 8, the electron injection efficiency and stability of the cathode 8 can be improved. The average thickness of the cathode 8 is not particularly limited, but is preferably about 50 to 10000 nm, and more preferably about 80 to 500 nm.

[0293] In the case of the top emission type, a material with a small work function or an alloy containing them is made into a thickness of about 5 to 20 nm, which has translucency, and then a highly translucent conductive material such as ITO is formed thereon with a thickness of about 100 to 500 nm. In addition, the organic electroluminescent element 1 described in this embodiment is a bottom emission type, so there is no special requirement for the light translucency of the cathode 8.

[0294] A hole injection layer 4 and a hole transport layer 5 are provided on the anode 3. The hole injection layer 4 has a function of receiving holes injected from the anode 3 and transporting them to the hole transport layer 5, and the hole transport layer 5 has a function of transporting holes injected from the hole injection layer 4 to the light-emitting layer 6. Examples of hole injection materials and hole transport materials constituting the hole injection layer 4 and the hole transport layer 5 include metal or metal-free phthalocyanine compounds such as phthalocyanine, copper phthalocyanine (CuPc), and iron phthalocyanine, polyarylamine, fluorene-arylamine copolymer, fluorene-dithiophene copolymer, poly(N-vinylcarbazole), polyvinylpyrene, polyvinylanthracene, polythiophene, polyalkylthiophene, polyhexylthiophene, poly(p-phenylene vinylene), polythiophene acetylene, pyrene formaldehyde resin, ethylcarbazole formaldehyde resin, or derivatives thereof, and one or more of them may be used in combination.

[0295] In addition, the hole injection material or hole transport material can also be used as a mixture with other compounds. As an example, a mixture containing polythiophene can include poly (3,4-ethylenedioxythiophene / styrene sulfonic acid) (PEDOT / PSS) and the like. In the hole injection layer 4 and the hole transport layer 5, according to the type of material used in the anode 3 and the light-emitting layer 6, from the perspectives of optimizing the injection efficiency and transport efficiency of holes, preventing the reabsorption of the radiated light from the light-emitting layer 6, heat resistance, etc., one or more suitable materials are appropriately selected, or used in combination.

[0296] For example, in the hole injection layer 4, the difference between the hole conduction level (Ev) and the work function of the material used in the anode 3 is small. In order to prevent the reabsorption of the radiated light, it is preferred to use a material without an absorption band in the visible light region. In addition, in the hole transport layer 5, no excited complex (exciplex) or charge transfer complex is formed between the constituent material of the light-emitting layer 6. In order to prevent the energy transfer of the excitons generated in the light-emitting layer 6 or the injection of electrons from the light-emitting layer 6, it is preferred to use a material with a large singlet excitation energy, a large band gap energy, and a shallow electron conduction potential (Ec) compared to the exciton energy of the light-emitting layer 6. When ITO is used in the anode 3, examples of materials suitable for use in the hole injection layer 4 and the hole transport layer 5 can be listed respectively: poly (3,4-ethylenedioxythiophene / styrenesulfonic acid) (PEDOT / PSS) and poly (N-vinylcarbazole) (PVK).

[0297] In addition, when the light-emitting layer 6 formed on the hole transport layer 5 is formed by a wet method, the hole transport material constituting the hole transport layer 5 can be selected from a material that is insoluble in (does not swell or dissolve) the solvent of the liquid material used to form the light-emitting layer. In addition, when the electron transport layer 7 is formed by a wet method, the solvent of the liquid material used in the formation of the electron transport layer 7 may cause the hole transport material to swell or dissolve, so it is preferred to use a material that is insoluble in the solvent of the liquid material used to form the electron transport layer.

[0298] The average thickness of the hole injection layer 4 is not particularly limited, but is preferably about 10 to 150 nm, more preferably about 20 to 100 nm. The average thickness of the hole transport layer 5 is not particularly limited, but is preferably about 10 to 150 nm, more preferably about 15 to 50 nm.

[0299] On the hole transport layer 5, that is, adjacent to the surface on the opposite side of the hole injection layer 4, a light-emitting layer 6 is provided. Electrons are supplied (injected) from the cathode 8 through the electron transport layer 7, and holes are supplied (injected) from the hole transport layer 5 to the light-emitting layer 6. Then, holes and electrons are recombined inside the light-emitting layer 6, and excitons are generated by the energy released during the recombination. When the excitons return to the ground state, energy (fluorescence or phosphorescence) is released (light emission).

[0300] The constituent materials of the light-emitting layer 6 include: benzene compounds such as 1,3,5-tris[(3-phenyl-6-trifluoromethyl)quinoxaline-2-yl]benzene (TPQ1) and 1,3,5-tris[{3-(4-tert-butylphenyl)-6-trifluoromethyl}quinoxaline-2-yl]benzene (TPQ2), low molecular weight materials such as tris(8-hydroxyquinoline)aluminum(III) (Alq3) and fac-tris(2-phenylpyridine)iridium (Ir(ppy)3), low molecular weight or high molecular weight materials such as oxadiazole materials, triazole materials, and carbazole materials, and high molecular weight materials such as polyfluorene materials, polyparaphenylene vinylene materials, polypyrrole materials, polyacetylene materials, and polyaniline materials. One or more of these materials may be used in combination.

[0301] The light-emitting layer 6 may be composed of a single material or a combination of multiple materials depending on the light-emitting color. In addition, a two-component system of a guest material that emits light and a host material that transports electrons or holes may be used. When a host-guest two-component system is used, the concentration of the guest material in the light-emitting layer 6 is generally about 0.1 to 1% by weight relative to the host material.

[0302] In addition, when the electron transport layer 7 formed on the light-emitting layer 6 is formed by a wet method, the constituent material of the light-emitting layer 6 can be selected from materials that are insoluble (do not swell or dissolve) in the solvent of the liquid material for forming the electron transport layer. The electron transport layer containing the electron transport material of the present invention can be constructed using a protic polar solvent (particularly alcohol), and therefore, the light-emitting layer 6 is preferably a layer insoluble in a protic polar solvent, and more preferably a layer insoluble in alcohol.

[0303] The average thickness of the light-emitting layer 6 is not particularly limited, but is preferably about 10 to 150 nm, and more preferably about 20 to 100 nm.

[0304] An electron transport layer 7 is provided between the light emitting layer 6 and the cathode 8. The electron transport layer 7 has a function of transporting electrons injected from the cathode 8 to the light emitting layer 6. As a constituent material of the electron transport layer 7, the electron transport material described in the third embodiment of the present invention can be used.

[0305] The average thickness of the electron transport layer is not particularly limited, but is preferably about 1 to 100 nm, more preferably about 1 to 50 nm, and further preferably about 5 to 50 nm.

[0306] In the organic electroluminescent element 1, a cathode 8 is provided on the electron transport layer 7, that is, adjacent to the surface on the opposite side of the light-emitting layer 6. By having an electron transport layer 7 using the electron transport material of the present invention, even if an electron injection layer using an unstable compound such as NaF or LiF is not provided, the cathode 8 is directly formed on the electron transport layer 7, and the luminous efficiency of the light-emitting layer can be improved, thereby improving the degree of freedom in optical design.

[0307] Next, a sealing member 9 is provided to cover the organic electroluminescent element 1 (anode 3, hole injection layer 4, hole transport layer 5, light-emitting layer 6, electron transport layer 7 and cathode 8), and hermetically seal it to block oxygen or moisture. By providing the sealing member 9, the reliability of the organic electroluminescent element 1 can be improved, and the effects of preventing deterioration and degradation (improving durability) can be obtained.

[0308] As the constituent material of the sealing member 9, for example, Al, Au, Cr, Nb, Ta, Ti or alloys containing them, silicon oxide, various resin materials, etc. can be listed. In addition, when a conductive material is used as the constituent material of the sealing member 9, in order to prevent short circuit, an insulating film is preferably provided between the sealing member 9 and the organic electroluminescent element 1 as required. In addition, the sealing member 9 can also be a flat plate, facing the substrate 2, and the space between them is sealed with a sealing material such as a thermosetting resin.

[0309] In addition, the organic electroluminescent element of the present invention is not limited to the organic electroluminescent element 1 .

[0310] In the organic electroluminescent element 1, the hole injection layer 4 and the hole transport layer 5 are formed as two layers between the anode 3 and the light-emitting layer 6, respectively. As needed, a single hole transport layer for hole injection from the anode 3 and hole transport to the light-emitting layer 6 can be made, or a structure in which three or more layers of the same composition or different compositions are stacked. The light-emitting layer is a single layer, but it can also be a structure in which multiple layers of the same composition or different compositions are stacked. For example, a structure in which multiple light-emitting layers of different compositions are stacked can be made according to the color of light to be emitted. The electron transport layer can also be a structure in which multiple layers of the same composition or different compositions are stacked.

[0311] In addition, the organic electroluminescent element of the present invention may further have a layer other than a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer between the anode and the cathode, or may have an electron injection layer containing NaF, LiF, etc. between the cathode 8 and the electron transport layer 7.

[0312] The organic electroluminescent element 1 can be produced, for example, by constructing an organic compound layer by a wet method and by the following production method.

[0313] First, a substrate 2 is prepared, and an anode 3 is formed on the substrate 2. The anode 3 can be formed, for example, by chemical vapor deposition (CVD) such as plasma CVD, thermal CVD, and laser CVD, dry plating such as vacuum evaporation, sputtering, and ion plating, wet plating such as electrolytic plating, immersion plating, and electroless plating, spraying, sol-gel method, MOD method, metal foil bonding, etc.

[0314] Next, the hole injection layer 4 and the hole transport layer 5 are sequentially formed on the anode 3 .

[0315] The hole injection layer 4 and the hole transport layer 5, for example, the hole injection material can be dissolved in a solvent or dispersed in a liquid material for forming a hole injection layer formed by a dispersion medium, and then dried (desolventized or de-dispersed), and then the hole transport material is dissolved in a solvent or dispersed in a liquid material for forming a hole transport layer formed by a dispersion medium. After being supplied to the hole injection layer 4, it is dried and formed. As a supply method for a liquid material for forming a hole injection layer and a liquid material for forming a hole transport layer, for example, various coating methods such as spin coating, casting, micro gravure coating, gravure coating, rod coating, roller coating, wire rod coating, dip coating, spray coating, screen printing, flexographic printing, offset printing, and inkjet printing can be used. By using such a coating method, it is relatively easy to form a hole injection layer 4 and a hole transport layer 5.

[0316] Examples of the solvent or dispersion medium used in the preparation of the liquid material for forming the hole injection layer and the liquid material for forming the hole transport layer include: inorganic solvents such as nitric acid, sulfuric acid, ammonia, hydrogen peroxide, water, carbon disulfide, carbon tetrachloride, and ethylene carbonate; ketone solvents such as methyl ethyl ketone (MEK), acetone, diethyl ketone, methyl isobutyl ketone (MIBK), methyl isopropyl ketone (MIPK), and cyclohexanone; alcohol solvents such as methanol, ethanol, isopropanol, ethylene glycol, diethylene glycol (DEG), and glycerol; ether solvents such as diethyl ether, diisopropyl ether, 1,2-dimethoxyethane (DME), 1,4-dioxane, tetrahydrofuran (THF), tetrahydropyran (THP), anisole, diethylene glycol dimethyl ether (diglyme), and diethylene glycol ethyl ether (carbitol). ; Cellosolve solvents such as methyl cellosolve, ethyl cellosolve, phenyl cellosolve; aliphatic hydrocarbon solvents such as hexane, pentane, heptane, cyclohexane; aromatic hydrocarbon solvents such as toluene, xylene, benzene; aromatic heterocyclic compound solvents such as pyridine, pyrazine, furan, pyrrole, thiophene, methylpyrrolidone; amide solvents such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA); halogen compound solvents such as chlorobenzene, dichloromethane, chloroform, 1,2-dichloroethane; ester solvents such as ethyl acetate, methyl acetate, ethyl formate; sulfur compound solvents such as dimethyl sulfoxide (DMSO) and cyclopentane; nitrile solvents such as acetonitrile, propionitrile, acrylonitrile; various organic solvents such as organic acid solvents such as formic acid, acetic acid, trichloroacetic acid, trifluoroacetic acid; or mixed solvents containing them.

[0317] Drying can be performed by, for example, leaving the sample in an atmospheric pressure or reduced pressure atmosphere, heating treatment, blowing of an inert gas, or the like.

[0318] In addition, oxygen plasma treatment may be performed on the upper surface of anode 3 before this step. This can impart lyophilicity to the upper surface of anode 3, remove (clean) organic matter attached to the upper surface of anode 3, and adjust the work function near the upper surface of anode 3.

[0319] Here, the conditions for oxygen plasma treatment are preferably set to, for example, a plasma power of about 100 to 800 W, an oxygen flow rate of about 50 to 100 mL / min, a transport speed of the treated component (anode 3) of about 0.5 to 10 mm / sec, and a temperature of the substrate 2 of about 70 to 90°C.

[0320] Next, the light-emitting layer 6 is formed on the hole transport layer 5 (on one surface side of the anode 3 ).

[0321] The light-emitting layer 6 can be formed, for example, by supplying a liquid material for forming the light-emitting layer, which is formed by dissolving the constituent material of the light-emitting layer 6 in a solvent or dispersing it in a dispersion medium, onto the hole transport layer 5, and then drying (removing the solvent or the dispersion medium). The supply method and drying method of the liquid material for forming the light-emitting layer are the same as those described in the formation of the hole injection layer 4 and the hole transport layer 5.

[0322] As the solvent or dispersion medium used for preparation for forming the light-emitting layer, the same substances as those described in the formation of the hole injection layer 4 and the hole transport layer 5 can be used. However, a solvent in which the hole transport layer 5 is insoluble can be selected according to the hole transport layer 5 to be formed.

[0323] Next, the electron transport layer 7 is formed on the light emitting layer 6 according to the following steps, for example.

[0324] (a) Step 1

[0325] First, a liquid material for forming an electron transport layer containing the metal complex represented by the above formulae (1) to (3) and, if necessary, a dopant such as a metal alkoxide is prepared.

[0326] As the solvent used in the preparation of the liquid material for forming the electron transport layer, a solvent in which the constituent material of the light-emitting layer 6 is difficult to swell or dissolve is preferred, and an insoluble solvent is more preferred. In this way, the deterioration of the light-emitting material or the dissolution of the light-emitting layer 6, and the extreme reduction in film thickness can be prevented. As a result, the reduction in the luminous efficiency of the organic electroluminescent element 1 can be prevented. In addition, since the liquid material for forming the electron transport layer may swell or dissolve the constituent material of the hole transport layer 5, the solvent is preferably a solvent in which the constituent material of the hole transport layer 5 is difficult to swell or dissolve, and an insoluble solvent is more preferred. Most of the materials constituting the hole transport layer 5 or the light-emitting layer 6 are difficult to dissolve in protic polar solvents, especially alcohols, so the solvent uses the alcohol solvent described above, preferably an alcohol with 1 to 10 carbon atoms. In this way, the reduction in luminous efficiency can be prevented, and the organic electroluminescent element 1 can be manufactured with better productivity.

[0327] (b) Step 2

[0328] Next, the prepared liquid material is supplied onto the light-emitting layer 6 and then dried (desolventized). Thus, an electron transport layer 7 containing the metal complex represented by the above formula (1) to the above formula (3) can be obtained. The supply method and drying method of the liquid material for forming the electron transport layer are the same as those described in the formation of the hole injection layer 4 and the hole transport layer 5.

[0329] In addition, the first step and the second step may be performed continuously, or the first step and the second step may be performed discontinuously, and a liquid material for forming an electron transport layer may be prepared in advance. The electron transport layer 7 may be constructed by supplying the previously prepared liquid material for forming an electron transport layer onto the light-emitting layer 6 and then drying (desolventizing).

[0330] Then, the cathode 8 is formed on the electron transport layer 7 .

[0331] The cathode 8 can be formed by, for example, vacuum deposition, sputtering, bonding of metal foil, application and baking of metal particle ink, or the like.

[0332] Finally, the sealing member 9 is applied so as to cover the obtained organic electroluminescent element 1, and is bonded to the substrate 2. Through the above steps, the organic electroluminescent element 1 can be obtained.

[0333] According to the above-mentioned manufacturing method, in the formation of the organic compound layer (hole injection layer 4, hole transport layer 5, light-emitting layer 6, electron transport layer 7) and the formation of the cathode 8 when using metal particle ink, no large-scale equipment such as a vacuum device is required, so it is possible to reduce the manufacturing time and manufacturing cost of the organic electroluminescent element 1. In addition, by using the inkjet method (droplet ejection method), it becomes easy to make large-area elements and separate coating of multiple colors.

[0334] In addition, the manufacturing method of the organic electroluminescent element 1 describes the case where a liquid phase process is used to manufacture the hole injection layer 4, the hole transport layer 5 and the light-emitting layer 6, but the manufacturing method of the organic electroluminescent element of the present invention may also form part or all of these layers by a gas phase process such as vacuum evaporation depending on the types of hole injection materials, hole transport materials and light-emitting materials used.

[0335] The organic electroluminescent element of the present invention can be used, for example, as a light source, etc. In addition, a display device can be constructed by arranging a plurality of organic electroluminescent elements of the present invention in a matrix.

[0336] In addition, the driving method of the display device is not particularly limited, and may be either an active matrix method or a passive matrix method.

[0337] The electrical energy supplied to the organic electroluminescent element of the present invention is mainly direct current, but pulse current and alternating current can also be used. There is no particular restriction on the current value and voltage value, but if the power consumption and life of the element are taken into consideration, the maximum brightness should be obtained with the lowest possible energy.

[0338] The "matrix" that constitutes a display device refers to the arrangement of pixels (pixels) for display in a grid shape, and text and images are displayed by a collection of pixels. The shape and size of the pixel are determined according to the purpose. For example, for the image and text display of personal computers, monitors, and televisions, quadrilateral pixels with a side length of less than 300μm are usually used. In the case of large displays such as display panels, pixels with a side length of mm are used. In the case of monochrome display, pixels of the same color can be arranged, but in the case of color display, red, green, and blue pixels are arranged for display. In this case, there are typically delta type and stripe type. Then, as a driving method for the matrix, it can be any of a passive matrix method and an active matrix method. The former has the advantage of a simple structure. Considering the working characteristics, the latter's active matrix is ​​sometimes more excellent, so this also needs to be used separately according to the purpose.

[0339] The organic electroluminescent element of the present invention can be a segment display device. "Segment" means that a pattern of a specified shape is formed in a manner of displaying predetermined information, and the determined area is illuminated. Examples include: a digital clock, a thermometer time or temperature display, an audio device or an induction cooker working status display, a car panel display, etc. Moreover, the matrix display and the segment display can coexist in the same panel.

[0340] The organic electroluminescent element of the present invention can be used as a backlight source for liquid crystal display devices, clocks, audio equipment, automobile panels, display boards, signs, etc., in order to improve the visibility of non-self-luminous display devices. In particular, as a backlight source for liquid crystal display devices and personal computers for which thinning is a problem, it can be made thinner and lighter than a conventional backlight source composed of a fluorescent lamp and a light guide plate.

[0341] Example

[0342] The compounds were identified by thin layer chromatography, FAB, MS or ASAP-TOF-MS. FAB and MS were measured using JMS700 manufactured by JEOL Ltd. ASAP-TOF-MS used LCT Premire XE manufactured by Waters Corporation.

[0343] In addition, for several ligands and complexes, DMSO-d6 was used as a deuterated solvent, and NMR (400 MHz) was measured using JNM-LA400 manufactured by JEOL Ltd.

[0344] As silica gel C300 used for column chromatography, Wako Pure Chemical Industries, Ltd. Wacol C300 (C300) and Fuji Silicone Chemical Co., Ltd. Chromatorex NH2 (NH2) were used.

[0345] [1] Synthesis of metal complexes

[0346] [A] Metal complex represented by formula (1)

[0347] [A-1] Synthesis of L101-M complex (M = Cs, Rb)

[0348] [A-1-1] Synthesis of ligand L101

[0349] (1-1-1) Synthesis of intermediate: Synthesis of N-(3-chlorophenyl)-3-methoxy-2-nitrosoaniline

[0350] [Chemical formula 39]

[0351]

[0352] 3-Chloroaniline (3.16 mL, 30 mmol) was added dropwise to a solution of KOtBu (10 g, 180 mmol)-THF (80 mL) cooled to -70°C, and stirred for 30 minutes. A solution of 2-nitroanisole (3.1 mL, 30 mmol)-THF (20 mL) was added dropwise, and stirred at -50°C. After 2 hours, a saturated aqueous solution of ammonium chloride was added to stop the reaction. After the reaction was completed, the mixture was extracted with dichloromethane, and the organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography (C300, heptane: dichloromethane) to obtain N-(3-chlorophenyl)-3-methoxy-2-nitrosoaniline (6.28 g, 79.8%).

[0353] ASAP-TOF-MS m / z = 263 ([M+1] + )

[0354] (1-1-2) Synthesis of intermediate: 1-(3-chlorophenyl)-4-methoxy-2-phenyl-1H-benzimidazole

[0355] [Chemical formula 40]

[0356]

[0357] N-(3-chlorophenyl)-3-methoxy-2-nitrosoaniline (3.15 g, 14.4 mmol), benzylphenyl sulfone (3.35 g, 14.4 mmol) and KOtBu (13.5 g, 120 mmol) obtained in the above (1-1-1) were added to 144 mL of acetonitrile and stirred at room temperature for 16 hours. After the reaction was completed, the reaction solution was poured into water and concentrated under reduced pressure. Then, it was extracted with dichloromethane, and the organic layer was washed with water, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by column chromatography (C300, heptane: dichloromethane) to obtain 1-(3-chlorophenyl)-4-methoxy-2-phenyl-1H-benzimidazole (1.68 g, 41.8%).

[0358] (1-1-3) Synthesis of intermediate: 1-[3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-4-methoxy-2-phenyl-1H-benzimidazole

[0359] [Chemical formula 41]

[0360]

[0361] 1-(3-chlorophenyl)-4-methoxy-2-phenyl-1H-benzimidazole (1.68 g, 5.02 mmol), bis(pinacol)diboron (1.39 g, 5.48 mmol), tris(dibenzylideneacetone)dipalladium (0.17 g, 0.19 mmol), XPhos (0.22 g, 0.46 mmol), potassium acetate (1.47 g, 15 mmol) obtained in the above (1-1-2) were added to 18.8 mL of dioxane, degassed, and stirred at 80°C for 16 hours. After the reaction was completed, it was concentrated under reduced pressure, water was added, and extracted with dichloromethane. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography (C300, heptane:dichloromethane) to give 1-[3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-4-methoxy-2-phenyl-1H-benzimidazole (1.65 g, 77.1%).

[0362] (1-1-4) Synthesis of intermediate: 1-[3-(1,10-phenanthroline-2-yl)phenyl]-4-methoxy-2-phenyl-1H-benzimidazole

[0363] [Chemical formula 42]

[0364]

[0365] 1-[3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-4-methoxy-2-phenyl-1H-benzimidazole (1.8 g, 4.22 mmol), 2-bromo-1,10-phenanthroline (1.09 g, 4.22 mmol), tetrakis(triphenylphosphine)palladium (0.26 g, 0.23 mmol), and cesium carbonate (4.56 g, 14 mmol) obtained by repeatedly performing the above (1-1-3) were added to 27 mL of toluene, 4.5 mL of water, and 2.8 mL of ethanol, and stirred at 100°C for 16 hours. After the reaction was completed, water was added and the mixture was extracted with dichloromethane. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography (NH 2 , heptane:dichloromethane) to give 1-[3-(1,10-phenanthroline-2-yl)phenyl]-4-methoxy-2-phenyl-1H-benzimidazole (1.12 g, 55%).

[0366] (1-1-5) Synthesis of Ligand L101: 1-[3-(1,10-phenanthroline-2-yl)phenyl]-2-phenyl-1H-benzimidazol-4-ol

[0367] [Chemical formula 43]

[0368]

[0369] Pyridine hydrochloride (6.3 g, 54.6 mmol) was added to 1-[3-(1,10-phenanthroline-2-yl)phenyl]-4-methoxy-2-phenyl-1H-benzimidazole (1.12 g, 2.34 mmol) obtained in the above (1-1-4), and the mixture was stirred at 200°C for 16 hours. After the reaction was completed, water was added and the insoluble matter was filtered to obtain 1-[3-(1,10-phenanthroline-2-yl)phenyl]-2-phenyl-1H-benzimidazol-4-ol (L101) (1.00 g, 92.6%).

[0370] [A-1-2] Synthesis of complex: Synthesis of L101-Cs

[0371] [Chemical formula 44]

[0372]

[0373] A 50% cesium hydroxide aqueous solution (0.075 mL, 0.431 mmol)-methanol (3 mL) solution was added dropwise to 8 mL of toluene of L101 (0.2 g, 0.431 mmol) obtained in [A-1-1], and the mixture was stirred at room temperature for 16 hours. After the reaction was completed, the mixture was concentrated under reduced pressure, dried after adding heptane, and L101-Cs (0.23 g, 89.6%) was obtained.

[0374] FAB-MS m / z=597([M+1] + )

[0375] In addition, the NMR of the obtained complex is shown together with the NMR of L101. Figure 2 middle.

[0376] [A-1-3] Synthesis of complex: Synthesis of L101-Rb

[0377] [Chemical formula 45]

[0378]

[0379] A 50% rubidium hydroxide aqueous solution (0.051 mL, 0.431 mmol)-methanol (3 mL) solution was added dropwise to 8 mL of toluene of L101 (0.2 g, 0.431 mmol) obtained in [A-1-1], and the mixture was stirred at room temperature for 16 hours. After the reaction was completed, the mixture was concentrated under reduced pressure, dried after adding heptane, and L101-Rb (0.2 g, 84.5%) was obtained.

[0380] FAB-MS m / z=548([M+1] + )

[0381] [A-2] Synthesis of L102-M complex (M=Cs).

[0382] [A-2-1] Synthesis of ligand L102.

[0383] (1-2-1) Synthesis of intermediate: Synthesis of 1-(1,10-phenanthroline-2-yl)amino-3-methoxy-2-nitrobenzene

[0384] [Chemical formula 46]

[0385]

[0386] 2-Amino-1,10-phenanthroline (3g, 15.4mmol) was added dropwise to a solution of KOtBu (5g, 44.6mmol)-THF (40mL) cooled to -70°C, and stirred for 30 minutes. A solution of 2-nitroanisole (1.84mL, 15mmol)-THF (10mL) was added dropwise, and stirred at -50°C. After 2 hours, a saturated aqueous solution of ammonium chloride was added to stop the reaction. After the reaction was completed, the mixture was extracted with dichloromethane, and the organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography (NH2, heptane: dichloromethane) to obtain 1-(1,10-phenanthroline-2-yl)amino-3-methoxy-2-nitrobenzene (4.47g, 90.3%).

[0387] (1-2-2) Synthesis of intermediate: Synthesis of 4-methoxy-2-phenyl-1-(1,10-phenanthroline-2-yl)-1H-benzimidazole

[0388] [Chemical formula 47]

[0389]

[0390] 1-(1,10-phenanthroline-2-yl)amino-3-methoxy-2-nitrobenzene (3.15 g, 14.4 mmol), benzylphenyl sulfone (3.35 g, 14.4 mmol) and KOtBu (13.5 g, 120 mmol) obtained in the above (1-2-1) were added to 144 mL of acetonitrile and stirred at room temperature for 16 hours. After the reaction was completed, the reaction solution was poured into water and concentrated under reduced pressure. Then, it was extracted with dichloromethane, and the organic layer was washed with water, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by column chromatography (NH2, heptane: dichloromethane) to obtain 4-methoxy-2-phenyl-1-(1,10-phenanthroline-2-yl)-1H-benzimidazole (2.42 g, 41.8%).

[0391] (1-2-3) Synthesis of ligand L102: Synthesis of 4-hydroxy-2-phenyl-1-(1,10-phenanthroline-2-yl)-1H-benzimidazole

[0392] [Chemical formula 48]

[0393]

[0394] Pyridine hydrochloride (6.3 g, 54.6 mmol) was added to 4-methoxy-2-phenyl-1-(1,10-phenanthroline-2-yl)-1H-benzimidazole (1.12 g, 2.34 mmol) obtained in the above (1-2-2), and the mixture was stirred at 200°C for 16 hours. After the reaction was completed, water was added and the insoluble matter was filtered to obtain 4-hydroxy-2-phenyl-1-(1,10-phenanthroline-2-yl)-1H-benzimidazole (L102) (1.00 g, 76.6%).

[0395] [A-2-2] Synthesis of complex: Synthesis of L102-Cs

[0396] [Chemical formula 49]

[0397]

[0398] A 50% cesium hydroxide aqueous solution (0.045 mL, 0.257 mmol)-methanol (1.92 mL) solution was added dropwise to the suspension of L102 (0.100 g, 0.257 mmol)-toluene (4.8 mL) obtained in [A-2-1] above, and stirred at room temperature for 1 hour. After the reaction was completed, it was concentrated under reduced pressure, dried after adding heptane, and L102-Cs (0.110 g, 82.7%) was obtained.

[0399] [A-2-3] Synthesis of composition (1a) containing L102-Cs

[0400] In order to achieve a condition in which L102 is in excess relative to the metal ion source (50% cesium hydroxide aqueous solution), the same operation as [A-2-2] was performed except that the 50% cesium hydroxide aqueous solution was changed from 0.045 mL (0.257 mol) to 0.022 mL (0.128 mol) to obtain a dried product (0.104 g, 89.0%). The obtained dried product was made into a composition (1a) containing L102-Cs.

[0401] [A-2-4] Synthesis of composition (1b) containing L102-Cs

[0402] In order to achieve the condition that the metal ion source (50% cesium hydroxide aqueous solution) is in excess relative to L102, the same operation as [A-2-2] was performed except that the 50% cesium hydroxide aqueous solution was changed from 0.045mL (0.257mL) to 0.058mL (0.333mL) to obtain a dry product (0.119g, 76.2%). The obtained dry product was made into a composition (1b) containing L102-Cs.

[0403] [A-3] Synthesis of L103-M complex (M = Cs, Li)

[0404] [A-3-1] Synthesis of ligand L103

[0405] (1-3-1) Synthesis of intermediate: 3-anilino-4-chloro-2-nitrosoanisole

[0406] [Chemical formula 50]

[0407]

[0408] Aniline (6.12 mL, 90 mmol) was added dropwise to a solution of KOtBu (30 g, 267 mmol)-THF (240 mL) cooled to -70°C, and the mixture was stirred for 30 minutes. A solution of 4-chloro-2-nitroanisole (16.9 g, 90 mmol)-THF (60 mL) was added dropwise, and the mixture was stirred at -50°C. After 2 hours, a saturated aqueous solution of ammonium chloride was added to stop the reaction. After the reaction was completed, the mixture was extracted with dichloromethane, and the organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography (C300, heptane: dichloromethane) to obtain N-3-anilino-4-chloro-2-nitrosoanisole (12.7 g, 53.6%).

[0409] (1-3-2) Synthesis of intermediate: Synthesis of 7-chloro-4-methoxy-1,2-diphenyl-1H-benzimidazole

[0410] [Chemical formula 51]

[0411]

[0412] 3-anilino-4-chloro-2-nitrosoanisole (4.0 g, 15.2 mmol), benzylphenyl sulfone (4.35 g, 18.7 mmol) and KOtBu (17.5 g, 156 mmol) obtained in (1-3-1) above were added to 187 mL of acetonitrile and stirred at room temperature for 16 hours. After the reaction was completed, the reaction solution was poured into water and concentrated under reduced pressure. Then, it was extracted with dichloromethane, and the organic layer was washed with water, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by column chromatography (C300, heptane: dichloromethane) to obtain 7-chloro-4-methoxy-1,2-diphenyl-1H-benzimidazole (1.37 g, 27.0%).

[0413] (1-3-3) Synthesis of intermediate: Synthesis of 1,2-diphenyl-4-methoxy-7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-benzimidazole

[0414] [Chemical formula 52]

[0415]

[0416] 7-Chloro-4-methoxy-1,2-diphenyl-1H-benzimidazole (2.81 g, 8.4 mmol), bis(pinacol)diboron (2.32 g, 9.12 mmol), tris(dibenzylideneacetone)dipalladium (0.28 g, 0.31 mmol), XPhos (0.36 g, 0.76 mmol), potassium acetate (2.45 g, 25 mmol) obtained in (1-3-2) above were added to 29.7 mL of dioxane, and stirred at 80°C for 16 hours after degassing. After the reaction was completed, it was concentrated under reduced pressure, water was added, and extraction was performed with dichloromethane. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography (C300, heptane:dichloromethane) to give 1,2-diphenyl-4-methoxy-7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-benzimidazole (2.65 g, 74.1%).

[0417] (1-3-4) Synthesis of intermediate: Synthesis of 1,2-diphenyl-4-methoxy-7-(1,10-phenanthroline-2-yl)-1H-benzimidazole

[0418] [Chemical formula 53]

[0419]

[0420] 1,2-diphenyl-4-methoxy-7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-benzimidazole (1.27 g, 2.98 mmol), 2-bromo-1,10-phenanthroline (0.77 g, 2.98 mmol), tetrakis(triphenylphosphine)palladium (0.17 g, 0.15 mmol), and cesium carbonate (3.01 g, 9.24 mmol) obtained by repeating the above (1-3-3) several times were added to 16 mL of toluene, 3.0 mL of water, and 1.9 mL of ethanol, and stirred at 100° C. for 16 hours. After the reaction was completed, water was added and the mixture was extracted with dichloromethane. The organic layer was dried over magnesium sulfate, concentrated under reduced pressure, and purified by column chromatography (NH2, heptane:dichloromethane) to give 1,2-diphenyl-4-methoxy-7-(1,10-phenanthroline-2-yl)-1H-benzimidazole (0.64 g, 45%).

[0421] (1-3-5) Synthesis of ligand: Synthesis of 1,2-diphenyl-4-hydroxy-7-(1,10-phenanthroline-2-yl)-1H-benzimidazole

[0422] [Chemical formula 54]

[0423]

[0424] Pyridine hydrochloride (2.77 g, 24.0 mmol) was added to 1,2-diphenyl-4-methoxy-7-(1,10-phenanthroline-2-yl)-1H-benzimidazole (0.49 g, 1.0 mmol) obtained in the above (1-3-4), and the mixture was stirred at 200°C for 16 hours. After the reaction was completed, water was added and the insoluble matter was filtered to obtain 1,2-diphenyl-4-hydroxy-7-(1,10-phenanthroline-2-yl)-1H-benzimidazole (L103) (0.38 g, 82.6%).

[0425] [A-3-2] Synthesis of L103-Cs

[0426] [Chemical formula 55]

[0427]

[0428] A 50% cesium hydroxide aqueous solution (0.028 mL, 0.161 mmol)-methanol (0.86 mL) solution was added dropwise to the suspension of L103 (0.075 g, 0.161 mmol)-toluene (2.15 mL) obtained in [A-3-1] above, and stirred at room temperature for 1 hour. After the reaction was completed, it was concentrated under reduced pressure, dried after adding heptane, and L103-Cs (0.078 g, 81.2%) was obtained.

[0429] [A-3-3] Synthesis of L103-Li

[0430] [Chemical formula 56]

[0431]

[0432] L103-Li (0.063 g, 82.9%) was obtained in the same manner as in [A-3-2] except that the 50% cesium hydroxide aqueous solution was replaced with a 4 mol / L lithium hydroxide aqueous solution (0.040 mL, 0.160 mmol).

[0433] [A-3-4] Synthesis of composition (2a) containing L103-Cs

[0434] In order to achieve a condition in which L103 is in excess relative to the metal ion source (50% cesium hydroxide aqueous solution), the same operation as [A-3-2] was performed except that the 50% cesium hydroxide aqueous solution was changed from 0.028 mL (0.161 mmol) to 0.022 mL (0.128 mmol) to obtain a dried product (0.070 g, 76.2%). The obtained dried product was made into a composition (2a) containing L103-Cs.

[0435] [A-3-5] Synthesis of Composition (2b) Containing L103-Cs

[0436] In order to achieve the condition that the metal ion source (50% cesium hydroxide aqueous solution) is in excess relative to L103, the same operation as [A-3-2] was performed except that the 50% cesium hydroxide aqueous solution was changed from 0.028mL (0.161mmol) to 0.056mL (0.322mmol), and a dry product (0.105g, 72.8%) was obtained. The obtained dry product was made into a composition (2b) containing L103-Cs.

[0437] [C] Metal complex represented by formula (3)

[0438] [C-1] Synthesis of L301-M complex (M=Cs)

[0439] [C-1-1] Synthesis of ligand L301

[0440] (3-1-1) Synthesis of intermediate: Synthesis of 3-amino-5-chloro-2-(2,6-dimethoxyphenyl)pyridine

[0441] [Chemical formula 57]

[0442]

[0443] 3-amino-2-bromo-5-chloropyridine (4.52 g, 21.8 mmol), 2,6-dimethoxyphenylboronic acid (4.77 g, 26.2 mmol), sodium carbonate (4.62 g, 43.6 mmol), tetrakis(triphenylphosphine)palladium (1.26 g, 10.9 mmol) were added to 80 mL of 1,2-dimethoxyethane and 40 mL of water, and stirred at 90°C for 3 hours. After the reaction was completed, water was added and extracted with dichloromethane. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained residue was purified by column chromatography (C300, dichloromethane) to obtain 3-amino-5-chloro-2-(2,6-dimethoxyphenyl)pyridine (5.31 g, 92%).

[0444] (3-1-2) Synthesis of intermediate: Synthesis of 3-chloro-9-methoxybenzofurano[3,2-b]pyridine

[0445] [Chemical formula 58]

[0446]

[0447] 3-Amino-5-chloro-2-(2,6-dimethoxyphenyl)pyridine (4.5 g, 17 mmol), sulfuric acid (0.9 mL, 16.9 mmol), and 30.2 mL of THF obtained in (3-1-1) above were placed in a flask and cooled to -10°C. Tert-butyl nitrite (3.6 mL, 30 mmol) was added dropwise to the solution, stirred for 3 hours, and then stirred at room temperature for 16 hours. After the reaction was completed, the reaction solution was concentrated. Water was added, extracted with ethyl acetate, and washed with saturated sodium bicarbonate aqueous solution and saturated brine. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography (C300, heptane: dichloromethane) to obtain 3-chloro-9-methoxybenzofurano[3,2-b]pyridine (2.77 g, 70%).

[0448] (3-1-3) Synthesis of intermediate: Synthesis of 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9-methoxybenzofurano[3,2-b]pyridine

[0449] [Chemical formula 59]

[0450]

[0451] 3-Chloro-9-methoxybenzofurano[3,2-b]pyridine (2.38 g, 10.2 mmol), bis(pinacol)diboron (2.88 g, 11.3 mmol), tris(dibenzylideneacetone)dipalladium (0.35 g, 0.38 mmol), XPhos (0.443 g, 0.93 mmol) and potassium acetate (3 g, 30.6 mmol) obtained in (3-1-2) above were added to 38.4 mL of dioxane and stirred at 80°C for 16 hours. After the reaction was completed, water was added and extracted with dichloromethane. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography (C300, heptane:dichloromethane) to give 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9-methoxybenzofuro[3,2-b]pyridine (2.88 g, 87.5%).

[0452] (3-1-4) Synthesis of intermediate: 3-(1,10-phenanthroline-2-yl)-9-methoxybenzofurano[3,2-b]pyridine

[0453] [Chemical formula 60]

[0454]

[0455] Toluene 54 mL, water 9 mL, and ethanol 5.6 mL were added to 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9-methoxybenzofurano[3,2-b]pyridine (2.80 g, 8.61 mmol), 2-bromo-1,10-phenanthroline (2.33 g, 9 mmol), tetrakis(triphenylphosphine)palladium (0.52 g, 0.45 mmol), and cesium carbonate (9.09 g, 27.9 mmol) obtained in the above (3-1-3), and stirred at 100°C for 16 hours. After the reaction was completed, water was added and extracted with dichloromethane. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography (NH 2 , heptane:dichloromethane) to give 3-(1,10-phenanthroline-2-yl)-9-methoxybenzofurano[3,2-b]pyridine (1.92 g, 58.4%).

[0456] (3-1-5) Synthesis of ligand: Synthesis of 3-(1,10-phenanthroline-2-yl)-benzofurano[3,2-b]pyridine-9-ol

[0457] [Chemical formula 61]

[0458]

[0459] Pyridine hydrochloride (12.9 g, 112 mmol) was added to 3-(1,10-phenanthroline-2-yl)-9-methoxybenzofurano[3,2-b]pyridine (1.81 g, 4.8 mmol) obtained in (3-1-4) above, and the mixture was stirred at 200°C for 16 hours. After the reaction, water was added and the precipitate was filtered to obtain 3-(1,10-phenanthroline-2-yl)-benzofurano[3,2-b]pyridine-9-ol (L301) (1.15 g, 65.8%).

[0460] [C-1-2] Synthesis of complex: Synthesis of L301-Cs complex

[0461] [Chemical formula 62]

[0462]

[0463] A 50% cesium hydroxide aqueous solution (0.24 mL, 1.38 mmol)-methanol (7 mL) solution was added dropwise to a suspension of the ligand L301 (0.5 g, 1.38 mmol)-toluene (17.6 mL) obtained in [C-1-1] above, and the mixture was stirred at room temperature for 16 hours. The reaction solution was concentrated under reduced pressure, dried after adding heptane, and L301-Cs (0.43 g, 63.2%) was obtained.

[0464] FAB-MS: m / z = 496 ([M+1] + )

[0465] In addition, the NMR of the obtained complex is shown together with the NMR of L301. Figure 3 middle.

[0466] [C-2] Synthesis of L302-M complex (M = Cs, Rb, Li)

[0467] [C-2-1] Synthesis of ligand L302

[0468] (3-2-1) Synthesis of intermediate: Synthesis of 3-amino-2-(2,6-dimethoxyphenyl)pyridine

[0469] [Chemical formula 63]

[0470]

[0471] 105 mL of 1,2-dimethoxyethane and 52.5 mL of water were added to 3-amino-2-bromopyridine (5 g, 28.9 mmol), 2,6-dimethoxyphenylboronic acid (6.26 g, 34.4 mmol), sodium carbonate (6.07 g, 57.3 mmol), and tetrakis(triphenylphosphine)palladium (1.65 g, 1.43 mmol), and the mixture was stirred at 90°C for 3 hours after degassing. After the reaction was completed, water was added and the mixture was extracted with dichloromethane. After concentration, the mixture was recrystallized with heptane and dichloromethane to obtain 3-amino-2-(2,6-dimethoxyphenyl)pyridine (6.25 g, 93%).

[0472] (3-2-2) Synthesis of intermediate: Synthesis of 9-methoxybenzofurano[3,2-b]pyridine

[0473] [Chemical formula 64]

[0474]

[0475] 3-Amino-2-(2,6-dimethoxyphenyl)pyridine (5.88 g, 25.5 mmol) and sulfuric acid (1.34 mL, 25.5 mmol) obtained in (3-2-1) above were added to 46 mL of THF and 138 mL of acetic acid and stirred at -15°C. Tert-butyl nitrite (5.4 mL, 45 mol) was then added. Stir at -15°C for 3 hours and then at room temperature for 16 hours. After the reaction was completed, the mixture was concentrated under reduced pressure and water was injected. The mixture was then extracted with ethyl acetate, and the organic layer was washed with an aqueous sodium bicarbonate solution and brine, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by column chromatography (NH2, heptane: dichloromethane) and recrystallized from heptane to obtain 9-methoxybenzofurano[3,2-b]pyridine (3.7 g, 73.8%).

[0476] (3-2-3) Synthesis of intermediate: Synthesis of 6-bromo-9-methoxybenzofurano[3,2-b]pyridine

[0477] [Chemical formula 65]

[0478]

[0479] The 9-methoxybenzofurano[3,2-b]pyridine (3.75 g, 18.8 mmol) obtained by repeatedly carrying out the above (3-2-2) was dissolved in 145 mL of methanol. The solution was cooled to 0°C, bromine (3.24 g, 20.3 mmol) was added, and stirred at room temperature for 2 hours. After the reaction was completed, it was concentrated under reduced pressure and a 5wt% sodium thiosulfate-5wt% sodium bicarbonate aqueous solution was injected. Then it was extracted with ethyl acetate, the organic layer was dried with magnesium sulfate, and concentrated under reduced pressure. The residue was recrystallized from heptane-ethanol to obtain 6-bromo-9-methoxybenzofurano[3,2-b]pyridine (9.63 g, 65.3%).

[0480] (3-2-4) Synthesis of intermediate: 9-methoxy-6-phenylphosphonylbenzofurano[3,2-b]pyridine

[0481] [Chemical formula 66]

[0482]

[0483] A THF 180ml solution of 6-bromo-9-methoxybenzofurano[3,2-b]pyridine (5.01g, 18mmol) obtained in (3-2-3) above was cooled to -80°C. 2.6M n-butyllithium (9.69mL, 25.2mmol) was added dropwise and stirred for 2 hours. Diethylamino(chloro)phenylphosphine (5.43g, 25.2mmol) was further added and stirred for 30 minutes, and then stirred at room temperature. After that, it was cooled to 0°C, hydrochloric acid was added, and stirred at room temperature. After the reaction was completed, it was concentrated under reduced pressure and neutralized with aqueous sodium bicarbonate solution. Then, it was extracted with dichloromethane, and the organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography to obtain 9-methoxy-6-phenylphosphonobenzofurano[3,2-b]pyridine (4.25g, 72.8%).

[0484] (3-2-5) Synthesis of intermediate: Synthesis of 9-methoxy-6-(phenanthroline (phenyl)phosphonyl)benzofurano[3,2-b]pyridine

[0485] [Chemical formula 67]

[0486]

[0487] 9-methoxy-6-phenylphosphonylbenzofurano[3,2-b]pyridine (3.01 g, 12 mmol), 2-bromophenanthroline (3.73 g, 14.4 mmol), palladium acetate (54 mg, 0.24 mmol), 1,3-bis(diphenylphosphino)propane (198 mg, 0.48 mmol) and 24 mL of triethanolamine obtained in the above (3-2-4) were added to 48 mL of toluene and stirred at 140°C for 30 hours. After the reaction was completed, it was concentrated under reduced pressure, and the obtained residue was poured into water and extracted with dichloromethane. The obtained organic layer was washed with water, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by column chromatography (NH2, heptane: dichloromethane) to obtain 9-methoxy-6-(phenanthroline (phenyl) phosphonyl)benzofurano[3,2-b]pyridine (3.01 g, 50%).

[0488] (3-2-6) Synthesis of ligand: Synthesis of 9-hydroxy-6-(phenanthroline (phenyl)phosphonyl)benzofurano[3,2-b]pyridine (L302)

[0489] [Chemical formula 68]

[0490]

[0491] 9-Methoxy-6-phenanthroline (phenyl) phosphonylbenzofurano [3,2-b] pyridine (1.50 g, 3.0 mmol) obtained in (3-2-5) above was added to 8.12 g of pyridine hydrochloride and stirred at 200°C for 1 hour. After the reaction was completed, water was added and the insoluble matter was filtered out. The obtained insoluble matter was dissolved in dichloromethane, washed in the order of saturated NaHCO3 aqueous solution, saturated ammonium chloride aqueous solution, and water, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was recrystallized from heptane-ethanol to obtain 9-hydroxy-6-(phenanthroline (phenyl) phosphonyl)benzofurano [3,2-b] pyridine (L302) (904 mg, 61.7%).

[0492] [C-2-2] Synthesis of complex: Synthesis of L302-Cs complex

[0493] [Chemical formula 69]

[0494]

[0495] A 50% cesium hydroxide aqueous solution (0.035 mL, 0.2 mmol)-methanol (1 mL) solution was added dropwise to a solution of the ligand L302 (0.98 g, 0.2 mmol)-toluene (2.5 mL) obtained by repeatedly performing the above [C-2-1], and the mixture was stirred at room temperature for 1 hour. The reaction solution was concentrated under reduced pressure, dried after adding heptane, and L302-Cs (71 mg, 57.5%) was obtained.

[0496] FAB-MS: m / z = 620 ([M+1] + )

[0497] In addition, the NMR of the obtained complex is shown together with the NMR of L302. Figure 4 middle.

[0498] [C-2-3] Synthesis of complex: Synthesis of L302-Rb complex

[0499] [Chemical formula 70]

[0500]

[0501] A 50% rubidium hydroxide aqueous solution (0.041 mL, 0.2 mmol)-methanol (1 mL) solution was added dropwise to a solution of ligand L302 (0.98 g, 0.2 mmol)-toluene (2.5 mL) obtained by repeatedly performing the above [C-2-1], and the mixture was stirred at room temperature for 1 hour. The reaction solution was concentrated under reduced pressure, dried after adding heptane, and L302-Rb (87 mg, 70.5%) was obtained.

[0502] FAB-MS: m / z = 573 ([M+1] + )

[0503] [C-2-4] Synthesis of complex: Synthesis of L302-Li complex

[0504] [Chemical formula 71]

[0505]

[0506] A 4 mol / L lithium hydroxide aqueous solution (0.075 mL, 0.3 mmol)-methanol (1.5 mL) solution was added dropwise to a solution of the ligand L302 (0.146 g, 0.3 mmol)-toluene (3.75 mL) obtained in [C-2-1] above, and the mixture was stirred at room temperature for 1 hour. The reaction solution was concentrated under reduced pressure, dried after adding heptane, and L302-Li (136 mg, 92.0%) was obtained.

[0507] [C-3] Synthesis of L303-M complex (M = Cs, Rb)

[0508] [C-3-1] Synthesis of ligand L303

[0509] (3-3-1) Synthesis of intermediate: Synthesis of 6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)9-methoxybenzofurano[3,2-b]pyridine

[0510] [Chemical formula 72]

[0511]

[0512] 6-Bromo-9-methoxybenzofurano[3,2-b]pyridine (5.0 g, 18 mmol), bis(pinacolato)diboron (7.26 g, 28.6 mmol), tris(dibenzylideneacetone)dipalladium (0.577 g, 0.63 mmol), XPhos (0.377 g, 0.79 mmol), and potassium acetate (5.57 g, 56.8 mmol) obtained in the same manner as in (3-2-3) of [C-2] above were added to 66 mL of dioxane, and stirred at 80°C for 16 hours after degassing. After completion of the reaction, the mixture was concentrated under reduced pressure and extracted with dichloromethane. The organic layer was dried over magnesium sulfate and then concentrated under reduced pressure. The residue was purified by column chromatography (C300, heptane:dichloromethane) and recrystallized from methanol to give 6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)9-methoxybenzofurano[3,2-b]pyridine (3.11 g, 53%).

[0513] (3-3-2) Synthesis of intermediate: Synthesis of 6-(9-chloro-1,10-phenanthroline-2-yl)-9-methoxybenzofurano[3,2-b]pyridine

[0514] [Chemical formula 73]

[0515]

[0516] 6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)9-methoxybenzofurano[3,2-b]pyridine (3.2 g, 9.84 mmol), 2,9-dichloro-1,10-phenanthroline (2.46 g, 9.82 mmol), tetrakis(triphenylphosphine)palladium (0.382 g, 0.504 mmol), cesium carbonate (10.26 g, 31.6 mmol) obtained by repeatedly performing the above (3-3-1) were added to toluene (60.8 mL), ethanol (5.6 mL), and water (8.96 mL), degassed, and stirred at 100°C for 16 hours. After the reaction was completed, it was concentrated under reduced pressure, water was added, and extraction was performed with dichloromethane. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The residue was recrystallized from heptane-dichloromethane to give 6-(9-chloro-1,10-phenanthroline-2-yl)-9-methoxybenzofurano[3,2-b]pyridine (1.43 g, 71.0%).

[0517] (3-3-3) Synthesis of intermediate: Synthesis of 6-(9-diphenylphosphonyl-1,10-phenanthroline-2-yl)-9-methoxybenzofurano[3,2-b]pyridine

[0518] [Chemical formula 74]

[0519]

[0520] After synthesis with reference to the patent document Japanese Patent Application Publication No. 2017-120845, 6-(9-diphenylphosphino-1,10-phenanthroline-2-yl)-9-methoxybenzofurano[3,2-b]pyridine (1.7 g, 60.7 mmol) was obtained.

[0521] (3-3-4) Synthesis of Ligand L103: Synthesis of 9-Hydroxy-6-(9-diphenylphosphino-1,10-phenanthroline-2-yl)benzofurano[3,2-b]pyridine

[0522] [Chemical formula 75]

[0523]

[0524] 6-(9-diphenylphosphino-1,10-phenanthroline-2-yl)-9-methoxybenzofurano[3,2-b]pyridine (0.46 g, 0.8 mmol) obtained in the above (3-3-3) was added to pyridine hydrochloride (2.4 g, 21 mmol) and stirred at 200°C for 16 hours. After the reaction was completed, water was added, and the precipitate was filtered and washed with methanol to obtain 9-hydroxy-6-(9-diphenylphosphino-1,10-phenanthroline-2-yl)benzofurano[3,2-b]pyridine (L303) (0.30 g, 68%).

[0525] [C-3-2] Synthesis of complex: Synthesis of L303-Cs

[0526] [Chemical formula 76]

[0527]

[0528] A 50% cesium hydroxide aqueous solution (0.031 mL, 0.177 mmol)-methanol (1.5 mL) solution was added dropwise to a solution of the ligand L303 (0.10 g, 0.177 mmol)-toluene (4 mL) obtained in [C-3-1] above, and the mixture was stirred at room temperature for 16 hours. The reaction solution was concentrated under reduced pressure, dried after adding heptane, and L103-Cs (0.09 g, 72%) was obtained.

[0529] FAB-MS: m / z = 696 ([M+1] + )

[0530] [C-3-3] Synthesis of complex: Synthesis of L303-Rb

[0531] [Chemical formula 77]

[0532]

[0533] A 50% rubidium hydroxide aqueous solution (0.021 mL, 0.177 mmol)-methanol (1 mL) solution was added dropwise to a solution of the ligand L303 (0.10 g, 0.177 mmol)-toluene (2.7 mL) obtained in [C-3-1] above, and the mixture was stirred at room temperature for 16 hours. The reaction solution was concentrated under reduced pressure, dried after adding heptane, and L303-Rb (0.06 g, 56.5%) was obtained.

[0534] FAB-MS: m / z = 649 ([M+1] + )

[0535] [2]Manufacturing and evaluation of organic electroluminescent elements

[0536] (1) Manufacture of liquid materials

[0537] The metal complex obtained in the above [1] was dissolved in a protic polar solvent listed in Table 1 to prepare a liquid material for constructing an electron transport layer of an organic electroluminescent element.

[0538] For example, the metal complex L101-Cs is dissolved in 1-heptanol to prepare an alcohol solution of 7.5 g / L to 15 g / L.

[0539] The results of the dissolution test for each solvent are shown in Table 1. In Table 1, the case where there is undissolved matter is indicated by "×", the case where there is slightly undissolved matter is indicated by "△", and the case where it is completely dissolved is indicated by "

[0540] [Table 1]

[0541]

[0542] (2) Manufacturing of organic electroluminescent elements

[0543] (2-1) Component composition

[0544] Apart from Figure 1 The organic electroluminescent element (element (A)) having the element structure shown in FIG. 1 and an electron injection layer provided between the cathode and the electron transport layer is manufactured in whole Figure 1 An organic electroluminescent device (device (B)) having the device configuration shown below was obtained. The film thickness of each layer was as follows.

[0545] Component (A): anode / hole injection layer / hole transport layer / light-emitting layer / electron transport layer / cathode Anode: ITO (150nm)

[0546] Hole injection layer: PEDOT:PSS (35nm)

[0547] Hole transport layer: triphenylamine polymer (20nm)

[0548] Light-emitting layer: F8BT (manufactured by Aldrich, CAS: 210347-52-7) (60 nm)

[0549] Electron transport layer: Electron transport material listed in Table 2 (20 nm)

[0550] Cathode: Al (100nm)

[0551] Component (B): anode / hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode

[0552] Anode: ITO (150nm)

[0553] Hole injection layer: PEDOT:PSS (35nm)

[0554] Hole transport layer: triphenylamine polymer (20nm)

[0555] Light-emitting layer: F8BT (manufactured by Aldrich, CAS: 210347-52-7) (60 nm)

[0556] Electron transport layer: Electron transport material listed in Table 2 (20 nm)

[0557] Electron injection layer: LiF (0.5nm)

[0558] Cathode: Al (100nm)

[0559] (2-2) Materials used

[0560] An ITO substrate manufactured by Technoprene (film thickness: 150 nm) was used, and 2-propanol for cleaning the substrate, manufactured by Wako Pure Chemical Industries, Ltd., for use in the electronics industry, was used.

[0561] Hole injection layer

[0562] As a liquid material for forming the hole injection layer, a stock solution of PEDOT:PSS (Al4083 manufactured by Heraeus) was used as it was.

[0563] Hole transport layer

[0564] As a liquid material for forming the hole transport layer, a toluene solution (5 g / L) prepared by adding 1 phr of dicumyl peroxide to a triphenylamine polymer was used. Toluene was produced by Wako Pure Chemical Industries, Ltd.

[0565] The compounds used are shown below.

[0566] [Chemical formula 78]

[0567]

[0568] Triphenylamine polymer

[0569] CAS: 472960-35-3

[0570] [Chemical formula 79]

[0571]

[0572] Dicumyl peroxide

[0573] CAS: 80-43-3

[0574] Luminescent layer

[0575] The light emitting layer was formed using a toluene solution (10 g / L) of F8BT manufactured by Wako Pure Chemical Industries, Ltd.

[0576] The compounds used are shown below.

[0577] [Chemical formula 80]

[0578]

[0579] F8BT

[0580] (Poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazole-4,8-diyl)])

[0581] cas:210347-52-7

[0582] Electron transport layer

[0583] The electron transport layer was formed using the liquid materials for forming the electron transport layer listed in Table 2. The solvent used was that manufactured by Wako Pure Chemical Industries, Ltd.

[0584] The liquid material for forming the electron transport layer was prepared by dissolving the metal complex described in Table 2 in the solvent described in Table 2 so that the concentration became 7.5 g / L.

[0585] In addition, in order to make a component with added metal alkoxide to achieve the purpose of further driving voltage and long life, a liquid material for forming an electron transport layer with added metal alkoxide as a dopant was prepared. The preparation of the liquid material for forming an electron transport layer with added metal alkoxide is implemented by adding a metal alkoxide solution to a metal complex solution. The solution of the metal complex is prepared by dissolving the metal complex recorded in Table 2 in the solvent recorded in Table 2 to a concentration of 7.5 g / L. The metal alkoxide solution, in the case of lithium tert-butoxide (LiOnBu), is prepared by dissolving the reagent prepared by Kojun Chemical Research Institute Co., Ltd. in a glove box at a concentration of 5 g / L in the solvent recorded in Table 2. Then the 7.5 g / L solution of the metal complex is mixed with the 5 g / L metal alkoxide solution so that the dopant (metal alkoxide) is 10% by weight relative to the metal complex, and then used for film formation.

[0586] In addition, a liquid material for forming an electron transport layer for comparison was prepared in the same manner as above except that LiBPP was used instead of the metal complex.

[0587] The compounds used are shown below.

[0588] [Compound 81]

[0589]

[0590] LiBPP

[0591] (2-(2',2"-bipyridin-6'-yl)-phenol lithium)

[0592] cas:1049805-81-3

[0593] (2-3) Component Manufacturing

[0594] As a pretreatment of the ITO substrate, it was boiled and cleaned in 2-propanol for 5 minutes, and then immediately placed in a UV / O3 treatment device and subjected to O3 treatment by UV irradiation for 15 minutes.

[0595] The hole injection layer, the hole transport layer, the light emitting layer, and the electron transport layer were formed using a spin coater manufactured by IDEN and then dried in a N2 atmosphere.

[0596] The cathode (Al, purity 99.999%) and the electron injection layer (LiF) were deposited in a chamber with a thickness of 1×10 -4 Pa high vacuum evaporation device. The evaporation rate for LiF is For Al After the cathode film formation was completed, the device was directly moved into a glove box purged with nitrogen and sealed with a glass cover coated with a desiccant.

[0597] (3) Evaluation of organic electroluminescent elements

[0598] The voltage-current-luminance relationship of the produced organic EL element was customized. A voltage was applied from 0 V to 10 V using a DC voltage and current power supply monitor (6241A, 7351A manufactured by ADCMT) and the current value was measured at every 0.1 V.

[0599] In addition, the life of the organic EL element was measured using a service life evaluation measuring device (manufactured by Kyushu Instruments). The element was set in a constant temperature chamber at 25°C, and the change in brightness voltage accompanied by constant current drive was measured. However, the acceleration factor used for element evaluation was 1.758. By converting to 100Cd / m 2 The driving time is compared with the half-decay time to reach 1 / 2 of the initial brightness.

[0600] T=(L0 / L) 1.758 ×T1

[0601] (Where L0: Initial brightness [cd / m 2 ], L: converted brightness [cd / m 2 ], T1: measured brightness half-decay time, T: converted brightness half-decay time)

[0602] The relative lifetime is based on the lifetime of Example 3 [material complex (L301-Cs) + dopant (LiOBu) + electroinjection layer] (100).

[0603] (4) Examples and Comparative Examples

[0604] 1) Embodiment 1

[0605] In the manufacture of the organic electroluminescent element of (2) above, L101-Cs is used as a metal complex of an electron transport material, and LiOBu is used as a dopant to manufacture an element (A) without an electron injection layer or an element (B) with an electron injection layer. The driving voltage (V) and current efficiency (η) of the obtained element are measured. c ) and the physical property values ​​of the relative lifetime are shown together in Table 2. In addition, Table 2 also records the presence or absence of the electron injection layer.

[0606] 2) Examples 2 to 7, Comparative Example 1

[0607] The device was manufactured in the same manner as in Example 1 except that the liquid material for forming the electron transport layer in Example 1 was replaced with the one shown in Table 2. The driving voltage (V) and current efficiency (η c ) and the physical property values ​​of relative life are shown in Table 2.

[0608] (5) Evaluation and investigation

[0609] First, it can be seen that compared with the similar compound LiBPP of Comparative Example 1 (compounds having a structure in which a phenolate is connected to a pyridine ring), the elements (Examples 1 to 7) using the compounds of this embodiment (compounds having a nitrogen-containing fused ring obtained by condensing a ring containing a phenolate and an N-containing heterocyclic ring in the basic skeleton) have low driving voltage, high current efficiency, and long life. Although the reason is uncertain, it is considered that the compound of this embodiment can improve the film-forming property and electron transport property by having a structure fused with a phenolate and a pyridine ring or an imidazole ring relative to the compound of Comparative Example 1. In addition, it is believed that the fact that the compounds of this embodiment have a total of 3 carbon rings and heterocyclic rings relative to LiBPP of Comparative Example 1, and a total of 6 or more carbon rings and heterocyclic rings in the compounds of this embodiment also contribute to the improvement of film-forming property and electron transport property.

[0610] In addition, although L302-Cs used in Examples 4 and 5 has a phosphine oxide structure, which has been reported to be chemically unstable in the CP bond in an anionic state, the devices of Examples 4 and 5 can achieve a longer life than Comparative Example 1. Although the reason is uncertain, it is believed that although it has a phosphine oxide structure, the electron transport property is improved by having the complex structure shown in the present invention.

[0611] Furthermore, from the comparison between Example 4 and Example 5, it can be seen that the addition of metal alkoxide can achieve a lower driving voltage and a longer life.

[0612] [Table 2]

[0613]

[0614] For compositions (1a) and (1b) containing L102-Cs and compositions (2a) and (2b) containing L103-Cs, a liquid material for forming an electron transport layer was prepared using 2-methoxyethanol or 1-heptanol, and an organic electroluminescent element was manufactured using the liquid material. The manufactured element was confirmed to emit light.

[0615] Possibility of Industrial Application

[0616] The metal complex having a novel ligand of the present invention has both high durability and electron transporting property, and is suitable for use as an electron transporting material for an organic electroluminescent element.

[0617] Explanation of symbols

[0618] 1 Organic electroluminescent element

[0619] 2 substrate

[0620] 3 Anode

[0621] 4 Hole injection layer

[0622] 5. Hole Transport Layer

[0623] 6. Luminescent layer

[0624] 7 Electron Transport Layer

[0625] 8 Cathode

[0626] 9 Sealing parts

Claims

1. A metal complex, characterized in that Contains at least one phenanthroline group and a nitrogen-containing fused ring, and is represented by the following formula (1) or the following formula (3): [Chemical formula 1] In formula (1) or (3), R A1 ~ R A9 are each independently a single bond, an arylene group having 6 to 18 carbon atoms, or a heteroarylene group having 3 to 17 carbon atoms; R E1 ~ R E6 are each independently a single bond or a group represented by the following formula (4); R B1 ~ R B9 are each independently a hydrogen atom or an unsubstituted phenanthroline group; R F1 ~ R F6 Each independently represents a hydrogen atom or a phenanthroline group represented by any one of the following formulae (5a) to (5d); Selected from R B1 ~ R B9 One or more of the group consisting of is an unsubstituted phenanthroline group; Selected from R F1 ~ R F6 One or more of the group consisting of the above-mentioned groups is a phenanthroline group represented by any one of the following formulae (5a) to (5d); M is an alkali metal, Z is 1, X is O, [Chemical formula 2] In formula (4), R P1 , R P3 is a single bond, R P2 is an aryl group having 6 to 18 carbon atoms or a heteroaryl group having 3 to 17 carbon atoms; [Chemical formula 3] In formula (5a) to formula (5d), R G2 ~ R G9 are each independently a hydrogen atom or a group represented by the following general formula (6): [Chemical formula 4] -R P4 -P(=O)R P5 -R P6 (6) In formula (6), R P4 is a single bond, R P5 , R P6 are each independently an aryl group having 6 to 18 carbon atoms or a heteroaryl group having 3 to 17 carbon atoms, selected from R G2 ~R G9 6 or 7 of them are hydrogen atoms.

2. The metal complex according to claim 1, wherein R A1 ~ R A9 are each independently a single bond, a phenylene group, a naphthylene group, a pyridylene group, a bipyridylene group or a pyrimidylene group.

3. A metal complex, wherein the metal complex is any one selected from the group consisting of compounds represented by the following L101-M to L108-M, L301-M to L308-M, L317-M and L318-M, In addition, in the following, M is an alkali metal, [Chemical formula 5] [Chemical formula 6] [Chemical formula 7] 。 The metal complex according to claim 1 or 3, wherein the alkali metal is Rb or Cs.

5. A coordination compound, characterized in that The metal complex according to any one of claims 1 to 4 is used.

6. An electron transport material for an organic electroluminescent element, characterized in that: Contains the metal complex according to any one of claims 1 to 4. The electron transport material according to claim 6 , wherein the electron transport material further contains a dopant.

8. The electron transport material according to claim 7, wherein the dopant contains a metal alkoxide represented by the following formula (7a) and / or the following formula (7b): [Chemical formula 8] R H1 -OM 1 (7a) R H1 -OM 2 -OR H2 (7b) In formula (7a) and formula (7b), R H1 , R H2 Each independently represents an alkyl group, and M 1 Alkali metal, M 2 It is an alkaline earth metal.

9. The electron transport material according to claim 7 or 8, wherein the dopant contains one or more selected from the group consisting of alkali metal complexes of hydroxyquinoline, alkali metal complexes of pyridylphenolate, alkali metal complexes of bipyridylphenolate, and alkali metal complexes of isoquinolylphenolate.

10. The electron transport material according to claim 7 or 8, wherein the dopant contains one or more selected from the group consisting of alkali metal hydroxides, alkali metal halides, alkali metal carbonates, alkali metal bicarbonates, alkali metal organic acid salts having 1 to 9 carbon atoms, alkaline earth metal hydroxides, alkaline earth metal halides, alkaline earth metal carbonates, alkaline earth metal bicarbonates, and alkaline earth metal organic acid salts having 1 to 9 carbon atoms. 11 . The electron transport material according to claim 7 or 8 , wherein the electron transport material further contains a ligand constituting the metal complex. 12 . A liquid material comprising the electron transport material according to claim 6 and a protic polar solvent, and used for constructing an electron transport layer of an organic electroluminescent element. 13 . The liquid material according to claim 12 , wherein the protic polar solvent is an alcohol solvent having 1 to 12 carbon atoms. 14 . The liquid material according to claim 13 , wherein the alcohol solvent having 1 to 12 carbon atoms is a monovalent or divalent alcohol. 15 . The liquid material according to claim 12 , wherein the liquid material contains 0.01 to 10 wt % of the metal complex according to claim 1 .

16. An organic electroluminescent element, characterized in that: A method of providing an electron transport layer comprising the electron transport material according to any one of claims 6 to 11.

17. A method for manufacturing an organic electroluminescent element, characterized in that: The method comprises the step of constructing an electron transport layer of an organic electroluminescent element by a wet method using the liquid material according to any one of claims 12 to 15.

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