JP7590187B2 - Method for producing dinuclear iridium complexes - Google Patents

Description

The present invention relates to a method for producing a dinuclear iridium complex suitable as a light-emitting material for use in the light-emitting layer of an organic electroluminescence device.

As a light-emitting material for use in the light-emitting layer of an organic electroluminescence element, an iridium complex with high luminescence quantum efficiency is required. Iridium complexes are known to be derived from iridium dinuclear complexes, which are synthesized by the manufacturing methods described in, for example, Patent Documents 1 to 4.

In Patent Documents 1 and 2, iridium chloride is reacted with a ligand compound in the presence of water and an organic solvent, but because water is contained, the internal temperature of the reaction vessel does not rise above 100°C, and the reaction time is long.

In Patent Document 3, in order to increase the reaction temperature, a distillation process is carried out in addition to the conditions in Patent Documents 1 and 2, so that the reaction is carried out under conditions where the internal temperature of the reaction vessel after distillation is 100°C or higher, but this does not sufficiently shorten the reaction time.

In Patent Document 4, iridium chloride is reacted with a ligand compound (A) at an internal temperature of a reaction vessel of 100° C. or higher without adding water at the stage of mixing the raw materials, but the reaction time is not sufficiently shortened.

JP 2008-179617 A Special Publication No. 2005-521210 JP 2015-189687 A JP 2006-213686 A

The objective of the present invention is to provide a more efficient method for producing an iridium dinuclear complex. Specifically, the objective of the present invention is to provide a method for producing an iridium dinuclear complex in which the reaction time is significantly reduced.

As a result of studies conducted to solve the above problems, the present inventors discovered that the reaction time for producing a dinuclear iridium complex can be significantly shortened by reacting a compound (ligand compound) having a specific structure represented by formula (2) with iridium chloride in an alkoxy alcohol without adding water. Based on this knowledge, further studies led to the completion of the present invention.

The present invention provides the following [1] to [10].
[1] A method for producing an iridium dinuclear complex represented by formula (1), comprising reacting iridium chloride with a compound represented by formula (2) in an alkoxy alcohol without adding water.

[In formula (1) and formula (2),
R ¹ to R ⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, a cyano group, or a dendron, and these groups may have a substituent. Two adjacent groups among ^{R 3} to R ⁸ may be bonded to each other to form a ring together with the carbon atoms to which they are bonded, and the ring may have a substituent.

However, at least one of R ¹ and R ² is a halogen atom, an alkyl group, or a group represented by formula (3):

is a group represented by:

A represents =CH- or =N-. When A is =CH-, it may have a substituent. When A is =N-, two or more A are =N-. Multiple A's may be the same or different.

［式（１）及び式（２）中、
Ｒ^１～Ｒ^８は、それぞれ独立に、水素原子、ハロゲン原子、アルキル基、シクロアルキル基、アルコキシ基、シクロアルコキシ基、アルキルチオ基、シクロアルキルチオ基、アリール基、アリールオキシ基、アリールチオ基、アリールアルキル基、アリールアルコキシ基、アリールアルキルチオ基、アシル基、アシルオキシ基、アミド基、酸イミド基、イミン残基、置換アミノ基、置換シリル基、置換シリルオキシ基、置換シリルチオ基、置換シリルアミノ基、１価の複素環基、ヘテロアリールオキシ基、ヘテロアリールチオ基、アリールアルケニル基、アリールアルキニル基、置換カルボキシル基、シアノ基、又はデンドロンを表し、これらの基は置換基を有していてもよい。Ｒ^３～Ｒ^８のうち隣り合う２つの基が互いに結合してそれぞれが結合する炭素原子とともに環を形成してもよく、当該環は置換基を有していてもよい。
但し、Ｒ^１及びＲ^２の少なくとも一方は、ハロゲン原子、アルキル基、又は、式（３）：

で表される基である。
Ａは、＝ＣＨ－又は＝Ｎ－を表し、Ａが＝ＣＨ－である場合は置換基を有していてもよく、Ａが＝Ｎ－である場合は２つ以上のＡが＝Ｎ－である。複数存在するＡは、同一でも異なっていてもよい。
Ｒ^９及びＲ^１０は、それぞれ独立に、水素原子、ハロゲン原子、アルキル基、シクロアルキル基、アルコキシ基、シクロアルコキシ基、アルキルチオ基、シクロアルキルチオ基、アリール基、アリールオキシ基、アリールチオ基、アリールアルキル基、アリールアルコキシ基、アリールアルキルチオ基、アシル基、アシルオキシ基、アミド基、酸イミド基、イミン残基、置換アミノ基、置換シリル基、置換シリルオキシ基、置換シリルチオ基、置換シリルアミノ基、１価の複素環基、ヘテロアリールオキシ基、ヘテロアリールチオ基、アリールアルケニル基、アリールアルキニル基、置換カルボキシル基、シアノ基、又はデンドロンを表し、これらの基は置換基を有していてもよい。］

［式（４）中、
Ｒ^１１～Ｒ^１８は、それぞれ独立に、水素原子、ハロゲン原子、アルキル基、シクロアルキル基、アルコキシ基、シクロアルコキシ基、アルキルチオ基、シクロアルキルチオ基、アリール基、アリールオキシ基、アリールチオ基、アリールアルキル基、アリールアルコキシ基、アリールアルキルチオ基、アシル基、アシルオキシ基、アミド基、酸イミド基、イミン基、置換アミノ基、置換シリル基、置換シリルオキシ基、置換シリルチオ基、置換シリルアミノ基、１価の複素環基、ヘテロアリールオキシ基、ヘテロアリールチオ基、アリールアルケニル基、アリールアルキニル基、置換カルボキシル基、シアノ基、又はデンドロンを表し、これらの基は置換基を有していてもよい。Ｒ^１１～Ｒ^１８のうち隣り合う２つの基が互いに結合してそれぞれが結合する炭素原子とともに環を形成してもよい。］

［式（５）中、Ｒ^１～Ｒ^８及びＲ^１１～Ｒ^１８は前記に同じ。］ ^R9 and ^R10 each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, a cyano group, or a dendron, and these groups may have a substituent.]
[2] The method according to [1], wherein at least one of R ⁵ to R ⁸ is a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, a cyano group, or a dendron.
[3] The method according to [1] or [2], wherein two adjacent groups among R ⁵ to R ⁸ are bonded to each other to form a ring together with the carbon atoms to which they are bonded, and the ring may have a substituent.
[4] The method according to any one of [1] to [3], wherein one of R ¹ and R ² is a halogen atom, an alkyl group, or a group represented by formula (3).
[5] The method according to any one of [1] to [4], wherein R ² is a halogen atom, an alkyl group, or a group represented by formula (3).
[6] The method according to any one of [1] to [5], wherein R ² is a group represented by formula (3).
[7] The method according to any one of [1] to [6], wherein all of A are =N-, or all of A are =CH-, and the =CH- may have a substituent.
[8] The method according to any one of [1] to [7], wherein the alkoxy alcohol is an alkoxy alcohol having 3 to 12 carbon atoms.
[9] The method according to any one of [1] to [8], wherein the internal temperature of the reaction vessel during the reaction (temperature of the reaction solution) is 115° C. or higher.
[10] A method for producing a compound represented by formula (5) (iridium complex), comprising reacting iridium chloride with a compound represented by formula (2) in an alkoxy alcohol without adding water, and reacting the resulting compound represented by formula (1) with formula (4).

[In formula (1) and formula (2),
R ¹ to R ⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, a cyano group, or a dendron, and these groups may have a substituent. Two adjacent groups among ^{R 3} to R ⁸ may be bonded to each other to form a ring together with the carbon atoms to which they are bonded, and the ring may have a substituent.
However, at least one of R ¹ and R ² is a halogen atom, an alkyl group, or a group represented by formula (3):

It is a group represented by the following formula:
A represents ═CH— or ═N—, and when A is ═CH—, it may have a substituent, and when A is ═N—, two or more A are ═N—. A plurality of A may be the same or different.
^R9 and ^R10 each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, a cyano group, or a dendron, and these groups may have a substituent.]

[In formula (4),
R ¹¹ to R ¹⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine group, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, a cyano group, or a dendron, and these groups may have a substituent. Two adjacent groups among ^{R 11} to R ¹⁸ may be bonded to each other to form a ring together with the carbon atoms to which they are bonded.]

[In formula (5), R ¹ to R ⁸ and R ¹¹ to R ¹⁸ are the same as above.]

The manufacturing method of the present invention can significantly reduce the reaction time required to synthesize a dinuclear iridium complex.

Hereinafter, an embodiment of the present invention will be described.
1. Explanation of common terms
Terms commonly used in this specification have the following meanings unless otherwise specified.

Examples of "halogen atoms" include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

The "alkyl group" may be either linear or branched. The number of carbon atoms in this alkyl group is usually 1 to 12 (hereinafter, sometimes referred to as "C1 to C12 alkyl"). The alkyl group may have a substituent. Specific examples of the alkyl group that may have a substituent include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, a 3,7-dimethyloctyl group, a lauryl group, a trifluoromethyl group, a pentafluoroethyl group, a perfluorobutyl group, a perfluorohexyl group, a perfluorooctyl group, and the like. Among these, the tert-butyl group, the pentyl group, the hexyl group, the octyl group, the 2-ethylhexyl group, the decyl group, and the 3,7-dimethyloctyl group are preferred.

The number of carbon atoms in a "cycloalkyl group" is usually 3 to 12 (hereinafter sometimes referred to as "C3-C12 cycloalkyl"). The cycloalkyl group may have a substituent, and specific examples of cycloalkyl groups that may have a substituent include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclohexylmethyl group, and a cyclohexylethyl group.

The "alkoxy group" may be either linear or branched. The number of carbon atoms in this alkoxy group is usually 1 to 12 (hereinafter, sometimes referred to as "C1-C12 alkoxy"). The alkoxy group may have a substituent. Specific examples of the alkoxy group that may have a substituent include a methoxy group, an ethoxy group, a propyloxy group, an isopropyloxy group, a butoxy group, an isobutoxy group, a tert-butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a 2-ethylhexyloxy group, a nonyloxy group, a decyloxy group, a 3,7-dimethyloctyloxy group, a lauryloxy group, a trifluoromethoxy group, a pentafluoroethoxy group, a perfluorobutoxy group, a perfluorohexyl group, a perfluorooctyl group, a methoxymethyloxy group, and a 2-methoxyethyloxy group. Of these, pentyloxy, hexyloxy, octyloxy, 2-ethylhexyloxy, decyloxy, and 3,7-dimethyloctyloxy groups are preferred.

The number of carbon atoms in a "cycloalkoxy group" is usually 3 to 12 (hereinafter sometimes referred to as "C3-C12 cycloalkoxy"). The cycloalkoxy group may have a substituent, and specific examples of the cycloalkoxy group that may have a substituent include a cyclopropyloxy group, a cyclobutyloxy group, a cyclopentyloxy group, and a cyclohexyloxy group.

The "alkylthio group" may be either linear or branched. The number of carbon atoms in this alkylthio group is usually 1 to 12. The alkylthio group may have a substituent. Specific examples of the alkylthio group that may have a substituent include a methylthio group, an ethylthio group, a propylthio group, an isopropylthio group, a butylthio group, an isobutylthio group, a tert-butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a 2-ethylhexylthio group, a nonylthio group, a decylthio group, a 3,7-dimethyloctylthio group, a laurylthio group, and a trifluoromethylthio group. Of these, the pentylthio group, the hexylthio group, the octylthio group, the 2-ethylhexylthio group, the decylthio group, and the 3,7-dimethyloctylthio group are preferred.

The number of carbon atoms in a "cycloalkylthio group" is usually 3 to 12. The cycloalkylthio group may have a substituent. Specific examples of the cycloalkylthio group that may have a substituent include a cyclopropylthio group, a cyclobutylthio group, a cyclopentylthio group, and a cyclohexylthio group.

"Aryl group" refers to the atomic group remaining after removing one hydrogen atom directly bonded to a carbon atom constituting a ring from an aromatic hydrocarbon. Such aromatic hydrocarbons include those having condensed rings and those having two or more selected from independent benzene rings and condensed rings bonded directly or via a group such as vinylene. The number of carbon atoms in an aryl group is usually 6 to 60, preferably 6 to 48, and more preferably 6 to 20. Examples include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, and a pyrenyl group.

The aryl group may have a substituent. Examples of the substituent include an alkoxy group (particularly a C1-C12 alkoxy group, etc.), a cycloalkoxy group (particularly a C3-C12 cycloalkoxy group, etc.), an alkyl group (particularly a C1-C12 alkyl group, etc.), a cycloalkyl group (particularly a C3-C12 cycloalkyl group, etc.), a chlorine atom, a bromine atom, an alkoxyphenyl group (particularly a C1-C12 alkoxyphenyl group), an alkylphenyl group (particularly a C1-C12 alkylphenyl group), a monovalent heterocyclic group, etc. The aryl group may have 1 to 5 (particularly 1 to 3) groups selected from the group consisting of these substituents.

Examples of the aryl group which may have a substituent include a phenyl group, a C1-C12 alkoxyphenyl group, a C1-C12 alkylphenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthracenyl group, a 2-anthracenyl group, a 9-anthracenyl group, a pentafluorophenyl group, a mono- or di-(C1-C12 alkoxyphenyl)phenyl group, a mono- or di-(C1-C12 alkylphenyl)phenyl group, etc. Among these, a C1-C12 alkoxyphenyl group, a C1-C12 alkylphenyl group, a di-(C1-C12 alkoxyphenyl)phenyl group, a di-(C1-C12 alkylphenyl)phenyl group, etc. are preferred.

Examples of C1 to C12 alkoxyphenyl groups include methoxyphenyl, ethoxyphenyl, dimethoxyphenyl, propyloxyphenyl, 1,3,5-trimethoxyphenyl, methoxyethoxyphenyl, isopropyloxyphenyl, butoxyphenyl, isobutoxyphenyl, tert-butoxyphenyl, pentyloxyphenyl, isoamyloxyphenyl, hexyloxyphenyl, heptyloxyphenyl, octyloxyphenyl, nonyloxyphenyl, decyloxyphenyl, and dodecyloxyphenyl groups.

Examples of C1-C12 alkylphenyl groups include methylphenyl, ethylphenyl, dimethylphenyl, propylphenyl, mesityl, methylethylphenyl, isopropylphenyl, butylphenyl, isobutylphenyl, tert-butylphenyl, pentylphenyl, isoamylphenyl, hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl, decylphenyl, and dodecylphenyl groups.

"Arylene group" refers to the atomic group remaining after removing two hydrogen atoms directly bonded to carbon atoms constituting a ring from an aromatic hydrocarbon. The number of carbon atoms in an arylene group is usually 6 to 60, preferably 6 to 30, and more preferably 6 to 18.

The arylene group may have a substituent (e.g., an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, a monovalent heterocyclic group, a bromine atom, etc.). Examples of the arylene group that may have the substituent include a phenylene group, a naphthalenediyl group, an anthracenediyl group, a phenanthrenediyl group, a dihydrophenanthrenediyl group, a naphthacenediyl group, a fluorenediyl group, a pyrenediyl group, a perylenediyl group, a chrysenediyl group, a dibenzocycloheptanediyl group, and groups in which these groups have a substituent, and preferably the groups represented by formulas (A-1) to (A-23). The arylene group includes groups in which a plurality of these groups are bonded.

[In the formula, R and R ^a each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, or a monovalent heterocyclic group. A plurality of R and R ^a may be the same or different, and R ^a may be bonded to each other to form a ring together with the atom to which they are bonded.]

"Trivalent aromatic hydrocarbon group" refers to the atomic group remaining after removing three hydrogen atoms directly bonded to carbon atoms constituting a ring from an aromatic hydrocarbon. The number of carbon atoms in a trivalent aromatic hydrocarbon group is usually 6 to 60, preferably 6 to 30, and more preferably 6 to 18.

The trivalent aromatic hydrocarbon group may have a substituent (e.g., an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, a monovalent heterocyclic group, a bromine atom, etc.), and examples of the trivalent aromatic hydrocarbon group that may have the substituent include a benzenetriyl group, a naphthalenetriyl group, an anthracenetriyl group, a phenanthrenetriyl group, a dihydrophenanthrenetriyl group, a naphthanetriyl group, a fluorenetriyl group, a pyrenetriyl group, a perylenetriyl group, a chrysentrieyl group, a dibenzocycloheptanetriyl group, and groups in which these groups have a substituent, and preferably a trivalent group in which one R is a bond in the divalent groups represented by formulas (A-1) to (A-23). The trivalent aromatic hydrocarbon group includes groups in which a plurality of these groups are bonded.

The number of carbon atoms in the "aryloxy" group is usually 6 to 60, and preferably 7 to 48. The aryloxy group may have a substituent (alkyl group, cycloalkyl group, alkoxy group, cycloalkoxy group, aryl group, bromine atom, etc.), and examples of the aryloxy group that may have a substituent include a phenoxy group, a C1 to C12 alkoxyphenoxy group, a C1 to C12 alkylphenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, and a pentafluorophenyloxy group. Of these, a C1 to C12 alkoxyphenoxy group and a C1 to C12 alkylphenoxy group are preferred.

Examples of C1 to C12 alkoxyphenoxy groups include methoxyphenoxy groups, ethoxyphenoxy groups, dimethoxyphenoxy groups, propyloxyphenoxy groups, 1,3,5-trimethoxyphenoxy groups, methoxyethoxyphenoxy groups, isopropyloxyphenoxy groups, butoxyphenoxy groups, isobutoxyphenoxy groups, tert-butoxyphenoxy groups, pentyloxyphenoxy groups, isoamyloxyphenoxy groups, hexyloxyphenoxy groups, heptyloxyphenoxy groups, octyloxyphenoxy groups, nonyloxyphenoxy groups, decyloxyphenoxy groups, and dodecyloxyphenoxy groups.

Examples of C1-C12 alkylphenoxy groups include methylphenoxy groups, ethylphenoxy groups, dimethylphenoxy groups, propylphenoxy groups, 1,3,5-trimethylphenoxy groups, methylethylphenoxy groups, isopropylphenoxy groups, butylphenoxy groups, isobutylphenoxy groups, tert-butylphenoxy groups, pentylphenoxy groups, isoamylphenoxy groups, hexylphenoxy groups, heptylphenoxy groups, octylphenoxy groups, nonylphenoxy groups, decylphenoxy groups, and dodecylphenoxy groups.

The number of carbon atoms in an "arylthio group" is usually 6 to 60, and preferably 7 to 48. The arylthio group may have a substituent (e.g., an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, a monovalent heterocyclic group, a bromine atom, etc.), and examples of the arylthio group that may have a substituent include a phenylthio group, a C1-C12 alkoxyphenylthio group, a C1-C12 alkylphenylthio group, a 1-naphthylthio group, a 2-naphthylthio group, and a pentafluorophenylthio group. Of these, a C1-C12 alkoxyphenylthio group and a C1-C12 alkylphenylthio group are preferred.

The number of carbon atoms in the "arylalkyl group" is usually 7 to 60, and preferably 7 to 48. The arylalkyl group may have a substituent (e.g., an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, a monovalent heterocyclic group, a bromine atom, etc.), and examples of the arylalkyl group that may have the substituent include phenyl-C1 to C12 alkyl group, C1 to C12 alkoxyphenyl-C1 to C12 alkyl group, C1 to C12 alkylphenyl-C1 to C12 alkyl group, 1-naphthyl-C1 to C12 alkyl group, and 2-naphthyl-C1 to C12 alkyl group. Of these, C1 to C12 alkoxyphenyl-C1 to C12 alkyl group and C1 to C12 alkylphenyl-C1 to C12 alkyl group are preferred.

The number of carbon atoms in the "arylalkoxy group" is usually 7 to 60, preferably 7 to 48. The arylalkoxy group may have a substituent (e.g., an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, a monovalent heterocyclic group, a bromine atom, etc.), and examples of the arylalkoxy group that may have a substituent include phenyl-C1 to C12 alkoxy groups such as phenylmethoxy group, phenylethoxy group, phenylbutoxy group, phenylpentyloxy group, phenylhexyloxy group, phenylheptyloxy group, and phenyloctyloxy group; C1 to C12 alkoxyphenyl-C1 to C12 alkoxy group, C1 to C12 alkylphenyl-C1 to C12 alkoxy group, 1-naphthyl-C1 to C12 alkoxy group, and 2-naphthyl-C1 to C12 alkoxy group. Of these, C1 to C12 alkoxyphenyl-C1 to C12 alkoxy group and C1 to C12 alkylphenyl-C1 to C12 alkoxy group are preferred.

The number of carbon atoms in the "arylalkylthio group" is usually 7 to 60, and preferably 7 to 48. The arylalkylthio group may have a substituent (e.g., an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, a monovalent heterocyclic group, a bromine atom, etc.), and examples of the arylalkylthio group that may have the substituent include a phenyl-C1-C12 alkylthio group, a C1-C12 alkoxyphenyl-C1-C12 alkylthio group, a C1-C12 alkylphenyl-C1-C12 alkylthio group, a 1-naphthyl-C1-C12 alkylthio group, and a 2-naphthyl-C1-C12 alkylthio group. Of these, the C1-C12 alkoxyphenyl-C1-C12 alkylthio group and the C1-C12 alkylphenyl-C1-C12 alkylthio group are preferred.

The number of carbon atoms in the "acyl group" is usually 2 to 20, and preferably 2 to 18. The acyl group may have a substituent (e.g., an alkoxy group, a cycloalkoxy group, an aryl group, a monovalent heterocyclic group, a bromine atom, a fluorine atom, etc.), and examples of the acyl group that may have a substituent include an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a pivaloyl group, a benzoyl group, a trifluoroacetyl group, a pentafluorobenzoyl group, etc.

The number of carbon atoms in an "acyloxy group" is usually 2 to 20, and preferably 2 to 18. The acyloxy group may have a substituent (e.g., an alkoxy group, a cycloalkoxy group, an aryl group, a monovalent heterocyclic group, a bromine atom, etc.), and examples of the acyloxy group that may have a substituent include an acetoxy group, a propionyloxy group, a butyryloxy group, an isobutyryloxy group, a pivaloyloxy group, a benzoyloxy group, a trifluoroacetyloxy group, and a pentafluorobenzoyloxy group.

The number of carbon atoms in the "amide group" is usually 2 to 20, and preferably 2 to 18. The amide group also includes those having a substituent on the amide nitrogen atom (e.g., an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, a monovalent heterocyclic group, a bromine atom, a fluorine atom, etc.). Examples of the amide group include a formamide group, an acetamide group, a propioamide group, a butyroamide group, a benzamide group, a trifluoroacetamide group, a pentafluorobenzamide group, a diformamide group, a diacetamide group, a dipropioamide group, a dibutyroamide group, a dibenzamide group, a ditrifluoroacetamide group, a dipentafluorobenzamide group, etc.

An "acid imide group" refers to a monovalent residue obtained by removing one hydrogen atom bonded to the nitrogen atom from an acid imide. The number of carbon atoms in this acid imide group is usually 2 to 60, and preferably 2 to 48. Examples of acid imide groups include groups represented by the following structural formulas.

（式中、窒素原子から延びた線は結合手を表し、Ｍｅはメチル基、Ｅｔはエチル基、ｎ－Ｐｒはｎ－プロピル基を表す。以下、同じである。）

(In the formula, the line extending from the nitrogen atom represents a bond, Me represents a methyl group, Et represents an ethyl group, and n-Pr represents an n-propyl group. The same applies below.)

"Imine residue" means a monovalent residue obtained by removing one hydrogen atom from an imine compound (i.e., an organic compound having -N=C- in the molecule. Examples include aldimines, ketimines, and compounds in which the hydrogen atoms bonded to the nitrogen atoms in these molecules are replaced with alkyl groups, etc.). This imine residue usually has 2 to 20 carbon atoms, and preferably 2 to 18. Specific examples include groups represented by the following structural formulas.

（式中、ｉ－Ｐｒはイソプロピル基、ｎ－Ｂｕはｎ－ブチル基、ｔ－Ｂｕはｔｅｒｔ－ブチル基を表す。波線で示した結合は、「楔形で表される結合」及び／又は「破線で表される結合」であることを意味する。ここで、「楔形で表される結合」とは、紙面からこちら側に向かって出ている結合を意味し、「破線で表される結合」とは、紙面の向こう側に出ている結合を意味する。）

(In the formula, i-Pr represents an isopropyl group, n-Bu represents an n-butyl group, and t-Bu represents a tert-butyl group. The bond represented by a wavy line means a "bond represented by a wedge shape" and/or a "bond represented by a dashed line." Here, a "bond represented by a wedge shape" means a bond extending outward from the paper, and a "bond represented by a dashed line" means a bond extending outward from the paper.)

"Substituted amino group" means an amino group substituted with one or two groups selected from the group consisting of an alkyl group, an aryl group, an arylalkyl group, and a monovalent heterocyclic group. The alkyl group, aryl group, arylalkyl group, or monovalent heterocyclic group may have a substituent (e.g., an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, a monovalent heterocyclic group, a bromine atom, etc.). The number of carbon atoms in the substituted amino group, not including the number of carbon atoms in the substituent, is usually 1 to 60, and preferably 2 to 48.

Examples of substituted amino groups include methylamino, dimethylamino, ethylamino, diethylamino, propylamino, dipropylamino, isopropylamino, diisopropylamino, butylamino, isobutylamino, tert-butylamino, pentylamino, hexylamino, cyclohexylamino, heptylamino, octylamino, 2-ethylhexylamino, nonylamino, decylamino, 3,7-dimethyloctylamino, laurylamino, cyclopentylamino, dicyclopentylamino, cyclohexylamino, dicyclohexylamino, pyrrolidyl, piperidyl, ditrifluoromethylamino, phenylamino, diphenylamino, and C1-C12 alkoxyphenyl. Examples include amino group, di(C1-C12 alkoxyphenyl)amino group, di(C1-C12 alkylphenyl)amino group, 1-naphthylamino group, 2-naphthylamino group, pentafluorophenylamino group, pyridylamino group, pyridazinylamino group, pyrimidylamino group, pyrazylamino group, triazylamino group, phenyl-C1-C12 alkylamino group, C1-C12 alkoxyphenyl-C1-C12 alkylamino group, C1-C12 alkylphenyl-C1-C12 alkylamino group, di(C1-C12 alkoxyphenyl-C1-C12 alkyl)amino group, di(C1-C12 alkylphenyl-C1-C12 alkyl)amino group, 1-naphthyl-C1-C12 alkylamino group, 2-naphthyl-C1-C12 alkylamino group, etc.

"Substituted silyl group" means a silyl group substituted with one, two or three groups selected from the group consisting of an alkyl group, an aryl group, an arylalkyl group and a monovalent heterocyclic group. The number of carbon atoms in the substituted silyl group is usually 1 to 60, preferably 3 to 48. The alkyl group, aryl group, arylalkyl group or monovalent heterocyclic group may have a substituent.

Substituted silyl groups include trimethylsilyl, triethylsilyl, tripropylsilyl, triisopropylsilyl, dimethylisopropylsilyl, diethylisopropylsilyl, tert-butylsilyldimethylsilyl, pentyldimethylsilyl, hexyldimethylsilyl, heptyldimethylsilyl, octyldimethylsilyl, 2-ethylhexyldimethylsilyl, nonyldimethylsilyl, decyldimethylsilyl, 3,7-dimethyloctyldimethylsilyl, and lauryldimethylsilyl. , phenyl-C1-C12 alkylsilyl group, C1-C12 alkoxyphenyl-C1-C12 alkylsilyl group, C1-C12 alkylphenyl-C1-C12 alkylsilyl group, 1-naphthyl-C1-C12 alkylsilyl group, 2-naphthyl-C1-C12 alkylsilyl group, phenyl-C1-C12 alkyldimethylsilyl group, triphenylsilyl group, tri-p-xylylsilyl group, tribenzylsilyl group, diphenylmethylsilyl group, tert-butyldiphenylsilyl group, dimethylphenylsilyl group, etc. are examples.

"Substituted silyloxy group" means a silyloxy group substituted with one, two or three groups selected from the group consisting of an alkoxy group, an aryloxy group, an arylalkoxy group and a monovalent heterocyclic oxy group. The number of carbon atoms in the substituted silyloxy group is usually 1 to 60, preferably 3 to 48. The alkoxy group, aryloxy group, arylalkoxy group or monovalent heterocyclic oxy group may have a substituent.

Examples of substituted silyloxy groups include trimethylsilyloxy, triethylsilyloxy, tripropylsilyloxy, triisopropylsilyloxy, dimethylisopropylsilyloxy, diethylisopropylsilyloxy, tert-butylsilyldimethylsilyl, pentyldimethylsilyloxy, hexyldimethylsilyloxy, heptyldimethylsilyloxy, octyldimethylsilyloxy, 2-ethylhexyldimethylsilyloxy, nonyldimethylsilyloxy, decyldimethylsilyloxy, 3,7-dimethyloctyldimethylsilyloxy, lauryldimethylsilyloxy, ... Examples include a silyloxy group, a phenyl-C1-C12 alkylsilyloxy group, a C1-C12 alkoxyphenyl-C1-C12 alkylsilyloxy group, a C1-C12 alkylphenyl-C1-C12 alkylsilyloxy group, a 1-naphthyl-C1-C12 alkylsilyloxy group, a 2-naphthyl-C1-C12 alkylsilyloxy group, a phenyl-C1-C12 alkyldimethylsilyloxy group, a triphenylsilyloxy group, a tri-p-xylylsilyloxy group, a tribenzylsilyloxy group, a diphenylmethylsilyloxy group, a tert-butyldiphenylsilyloxy group, and a dimethylphenylsilyloxy group.

"Substituted silylthio group" means a silylthio group substituted with one, two or three groups selected from the group consisting of an alkylthio group, an arylthio group, an arylalkylthio group and a monovalent heterocyclic thio group. The number of carbon atoms in the substituted silylthio group is usually 1 to 60, preferably 3 to 48. The alkoxy group, arylthio group, arylalkylthio group or monovalent heterocyclic thio group may have a substituent.

Substituted silylthio groups include trimethylsilylthio, triethylsilylthio, tripropylsilylthio, triisopropylsilylthio, dimethylisopropylsilylthio, diethylisopropylsilylthio, tert-butylsilyldimethylsilylthio, pentyldimethylsilylthio, hexyldimethylsilylthio, heptyldimethylsilylthio, octyldimethylsilylthio, 2-ethylhexyldimethylsilylthio, nonyldimethylsilylthio, decyldimethylsilylthio, 3,7-dimethyloctyldimethylsilylthio, lauryldimethylsilylthio, ... Examples include silylthio group, phenyl-C1-C12 alkylsilylthio group, C1-C12 alkoxyphenyl-C1-C12 alkylsilylthio group, C1-C12 alkylphenyl-C1-C12 alkylsilylthio group, 1-naphthyl-C1-C12 alkylsilylthio group, 2-naphthyl-C1-C12 alkylsilylthio group, phenyl-C1-C12 alkyldimethylsilylthio group, triphenylsilylthio group, tri-p-xylylsilylthio group, tribenzylsilylthio group, diphenylmethylsilylthio group, tert-butyldiphenylsilylthio group, and dimethylphenylsilylthio group.

The term "substituted silylamino group" refers to a silylamino group substituted with one, two or three groups selected from the group consisting of an alkylamino group, an arylamino group, an arylalkylamino group and a monovalent heterocyclic amino group. The number of carbon atoms in the substituted silylamino group is usually 1 to 60, and preferably 3 to 48. The alkoxy group, arylamino group, arylalkylamino group or monovalent heterocyclic amino group may have a substituent.

Substituted silylamino groups include trimethylsilylamino, triethylsilylamino, tripropylsilylamino, triisopropylsilylamino, dimethylisopropylsilylamino, diethylisopropylsilylamino, tert-butylsilyldimethylsilylamino, pentyldimethylsilylamino, hexyldimethylsilylamino, heptyldimethylsilylamino, octyldimethylsilylamino, 2-ethylhexyldimethylsilylamino, nonyldimethylsilylamino, decyldimethylsilylamino, 3,7-dimethyloctyldimethylsilylamino, lauryldimethylsilylamino, Examples include silylamino group, phenyl-C1-C12 alkylsilyloxy group, C1-C12 alkoxyphenyl-C1-C12 alkylsilylamino group, C1-C12 alkylphenyl-C1-C12 alkylsilylamino group, 1-naphthyl-C1-C12 alkylsilylamino group, 2-naphthyl-C1-C12 alkylsilylamino group, phenyl-C1-C12 alkyldimethylsilylamino group, triphenylsilylamino group, tri-p-xylylsilylamino group, tribenzylsilylamino group, diphenylmethylsilylamino group, tert-butyldiphenylsilylamino group, dimethylphenylsilylamino group, etc.

"p-valent heterocyclic group" (p is an integer of 1 or more) means the atomic group remaining after removing p hydrogen atoms from the hydrogen atoms directly bonded to the carbon atoms or heteroatoms that constitute the ring from a heterocyclic compound. The p-valent heterocyclic group may have a substituent. Here, the heterocyclic compound refers to an organic compound having a cyclic structure in which the elements that constitute the ring are not only carbon atoms but also heteroatoms such as oxygen, sulfur, nitrogen, phosphorus, and boron in the ring. Examples of heterocyclic compounds include aromatic heterocyclic compounds and aliphatic heterocyclic compounds. Among p-valent heterocyclic groups, "p-valent aromatic heterocyclic groups" which are the atomic group remaining after removing p hydrogen atoms from the hydrogen atoms directly bonded to the carbon atoms or heteroatoms that constitute the ring from an aromatic heterocyclic compound are preferred, and "p-valent nitrogen-containing aromatic heterocyclic groups" are more preferred.

"Aromatic heterocyclic compound" refers to compounds in which the heterocycle itself is aromatic, such as oxadiazole, thiadiazole, thiazole, oxazole, thiophene, pyrrole, phosphole, furan, pyridine, pyrazine, pyrimidine, triazine, pyridazine, quinoline, isoquinoline, carbazole, and dibenzophosphole, as well as compounds in which an aromatic ring is condensed with a heterocycle, such as phenoxazine, phenothiazine, dibenzoborole, dibenzosilole, and benzopyran, even if the heterocycle itself does not exhibit aromaticity.

"Aliphatic heterocyclic compounds" include hydrofuran, pyran, hydropyran, dioxane, pyrrolidine, imidazolidine, pyrazolidine, piperidine, piperazine, morpholine, quinuclidine, hydrothiophene, thiane, etc.

The number of carbon atoms in the "monovalent heterocyclic group" (p = 1) is usually 2 to 60, and preferably 3 to 20. Note that the number of carbon atoms in the monovalent heterocyclic group does not include the number of carbon atoms of the substituents.

The monovalent heterocyclic group may have a substituent. Examples of the monovalent heterocyclic group that may have a substituent include a thienyl group, a pyrrolyl group, a furyl group, a pyridyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a piperidinyl group, a quinolinyl group, an isoquinolinyl group, a pyrimidinyl group, a triazinyl group, and groups in which the hydrogen atom in these groups is replaced with an alkyl group (e.g., C1-C12 alkyl), an alkoxy group (e.g., C1-C12 alkoxy), an aryl group, a bromine atom, or the like.

The number of carbon atoms in the "divalent heterocyclic group" (p = 2) is usually 2 to 60, and preferably 3 to 20. Note that the number of carbon atoms in the divalent heterocyclic group does not include the number of carbon atoms of the substituents.

The divalent heterocyclic group may have a substituent. Examples of the divalent heterocyclic group that may have a substituent include divalent groups obtained by removing two hydrogen atoms from the hydrogen atoms directly bonded to the carbon atoms or heteroatoms that constitute the ring from pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, carbazole, dibenzofuran, dibenzothiophene, dibenzosilole, phenoxazine, phenothiazine, acridine, dihydroacridine, furan, thiophene, azole, diazole, and triazole (these groups may have substituents such as alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, and bromine atoms), and preferably the groups represented by formulae (AA-1) to (AA-34). The divalent heterocyclic group includes groups in which a plurality of these groups are bonded.

［式中、Ｒ及びＲ^ａは、前記と同じ意味を表す。］

[In the formula, R and ^Ra have the same meanings as defined above.]

The number of carbon atoms in the "trivalent heterocyclic group" (p = 3) is usually 2 to 60, and preferably 3 to 20. Note that the number of carbon atoms in the trivalent heterocyclic group does not include the number of carbon atoms of the substituents.

The trivalent heterocyclic group may have a substituent. Examples of the trivalent heterocyclic group that may have a substituent include trivalent groups obtained by removing three hydrogen atoms from the hydrogen atoms directly bonded to the carbon atoms or heteroatoms that constitute the ring from pyridine, diazabenzene, triazine, azanaphthalene, diazanaphthalene, carbazole, dibenzofuran, dibenzothiophene, dibenzosilole, phenoxazine, phenothiazine, acridine, dihydroacridine, furan, thiophene, azole, diazole, and triazole (these groups may have substituents such as alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, aryl groups, and bromine atoms), and preferably, the divalent groups represented by formulae (AA-1) to (AA-34) above, in which one R is a bond. The trivalent heterocyclic group includes groups in which a plurality of these groups are bonded.

The number of carbon atoms in a "heteroaryloxy group" is usually 3 to 60, and preferably 3 to 48. The heteroaryloxy group may have a substituent. Examples of the heteroaryloxy group that may have a substituent include a thienyloxy group, a C1-C12 alkoxythienyloxy group, a C1-C12 alkylthienyloxy group, a pyridyloxy group, a C1-C12 alkoxypyridyloxy group, a C1-C12 alkylpyridyloxy group, and an isoquinolyloxy group. Of these, a C1-C12 alkoxypyridyloxy group and a C1-C12 alkylpyridyloxy group are preferred.

Examples of the C1 to C12 alkoxypyridyloxy group include methoxypyridyloxy group, ethoxypyridyloxy group, propyloxypyridyloxy group, isopropyloxypyridyloxy group, butoxypyridyloxy group, isobutoxypyridyloxy group, tert-butoxypyridyloxy group, pentyloxypyridyloxy group, hexyloxypyridyloxy group, cyclohexyloxypyridyloxy group, heptyloxypyridyloxy group, octyloxypyridyloxy group, 2-ethylhexyloxypyridyloxy group, nonyloxypyridyloxy group, decyloxypyridyloxy group, 3,7-dimethyloctyloxypyridyloxy group, lauryloxypyridyloxy group, etc.

Examples of the C1 to C12 alkylpyridyloxy group include methylpyridyloxy group, ethylpyridyloxy group, dimethylpyridyloxy group, propylpyridyloxy group, 1,3,5-trimethylpyridyloxy group, methylethylpyridyloxy group, isopropylpyridyloxy group, butylpyridyloxy group, isobutylpyridyloxy group, tert-butylpyridyloxy group, pentylpyridyloxy group, isoamylpyridyloxy group, hexylpyridyloxy group, heptylpyridyloxy group, octylpyridyloxy group, nonylpyridyloxy group, decylpyridyloxy group, dodecylpyridyloxy group, etc.

The number of carbon atoms in a "heteroarylthio group" is usually 6 to 60, and preferably 7 to 48. The heteroarylthio group may have a substituent. Examples of the heteroarylthio group that may have a substituent include a pyridylthio group, a C1-C12 alkoxypyridylthio group, a C1-C12 alkylpyridylthio group, and an isoquinolylthio group. Of these, a C1-C12 alkoxypyridylthio group and a C1-C12 alkylpyridylthio group are preferred.

The number of carbon atoms in the "arylalkenyl group" is usually 8 to 60, and preferably 8 to 48. The arylalkenyl group may have a substituent. Examples of the arylalkenyl group that may have a substituent include phenyl-C2-C12 alkenyl group ("C2-C12 alkenyl" means that the alkenyl portion has 2 to 12 carbon atoms. The same applies below.), C1-C12 alkoxyphenyl-C2-C12 alkenyl group, C1-C12 alkylphenyl-C2-C12 alkenyl group, 1-naphthyl-C2-C12 alkenyl group, and 2-naphthyl-C2-C12 alkenyl group. Of these, C1-C12 alkoxyphenyl-C2-C12 alkenyl group and C1-C12 alkylphenyl-C2-C12 alkenyl group are preferred.

The number of carbon atoms in the "arylalkynyl group" is usually 8 to 60, and preferably 8 to 48. The arylalkynyl group may have a substituent. Examples of the arylalkynyl group that may have a substituent include phenyl-C2-C12 alkynyl group ("C2-C12 alkynyl" means that the alkynyl portion has 2 to 12 carbon atoms. The same applies below.), C1-C12 alkoxyphenyl-C2-C12 alkynyl group, C1-C12 alkylphenyl-C2-C12 alkynyl group, 1-naphthyl-C2-C12 alkynyl group, and 2-naphthyl-C2-C12 alkynyl group. Of these, C1-C12 alkoxyphenyl-C2-C12 alkynyl group and C1-C12 alkylphenyl-C2-C12 alkynyl group are preferred.

The number of carbon atoms in a "substituted carboxyl group" is usually 2 to 60, and preferably 2 to 48, and refers to a carboxyl group substituted with an alkyl group, an aryl group, an arylalkyl group, or a monovalent heterocyclic group. Examples of the substituted carboxyl group include a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, an isopropoxycarbonyl group, a butoxycarbonyl group, an isobutoxycarbonyl group, a tert-butoxycarbonyl group, a pentyloxycarbonyl group, a hexyloxycarbonyl group, a cyclohexyloxycarbonyl group, a heptyloxycarbonyl group, an octyloxycarbonyl group, a 2-ethylhexyloxycarbonyl group, a nonyloxycarbonyl group, a decyloxycarbonyl group, a 3,7-dimethyloctyloxycarbonyl group, a dodecyloxycarbonyl group, a trifluoromethoxycarbonyl group, a pentafluoroethoxycarbonyl group, a perfluorobutoxycarbonyl group, a perfluorohexyloxycarbonyl group, a perfluorooctyloxycarbonyl group, a pyridyloxycarbonyl group, a naphthoxycarbonyl group, and a pyridyloxycarbonyl group. The alkyl group, aryl group, arylalkyl group, or monovalent heterocyclic group may have a substituent. The number of carbon atoms of the substituted carboxyl group does not include the number of carbon atoms of the substituent.

In the case where "two adjacent groups among ^R3 to ^R8 are bonded to each other to form a ring together with the carbon atoms to which they are bonded", examples of the group in which two adjacent groups are bonded to each other include the following groups. The group may have a substituent selected from an alkyl group, an aryl group, an alkylaryl group, a cycloalkyl group, a halogen atom, a 1,3,5-triazin-2-yl group having aryl groups as substituents at the 4th and 6th positions, a 1,3-pyrimidin-2-yl group having aryl groups as substituents at the 4th and 6th positions, a dendron, etc.

[In the formula, * indicates the carbon atom to which two adjacent groups among ^R3 to ^R8 are bonded.]

A "dendron" is a group having a regular dendritic branching structure with atoms or rings as branching points. Examples of metal complexes having a dendron as a partial structure (hereinafter also referred to as "metal complexes having a dendron") include structures described in WO 02/067343, JP 2003-231692 A, WO 2003/079736 A, WO 2006/097717 A, etc.

The dendron is preferably a group represented by formula (D-A) or formula (D-B).

[Wherein,
m ^DA1 , m ^DA2 and m ^DA3 each independently represent an integer of 0 or more and 10 or less.

G ^DA represents a nitrogen atom, a trivalent aromatic hydrocarbon group or a trivalent heterocyclic group, and these groups may have a substituent.

Ar ^DA1 , Ar ^DA2 and Ar ^DA3 each independently represent an arylene group or a divalent heterocyclic group, and these groups may have a substituent. When there are a plurality of Ar ^DA1 , Ar ^DA2 and Ar ^DA3 , they may be the same or different.

T ^DA represents an aryl group or a monovalent heterocyclic group, and these groups may have a substituent. A plurality of T ^DA may be the same or different.

[Wherein,
^mDA1 , ^mDA2 , ^mDA3 , ^mDA4 , ^mDA5 , ^mDA6 and ^mDA7 each independently represent an integer of 0 or more and 10 or less.

G ^DA represents a nitrogen atom, a trivalent aromatic hydrocarbon group or a trivalent heterocyclic group, and these groups may have a substituent. A plurality of G ^DA may be the same or different.

Ar ^DA1 , Ar ^DA2 , Ar ^DA3 , Ar ^DA4 , Ar ^DA5 , Ar ^DA6 and Ar ^DA7 each independently represent an arylene group or a divalent heterocyclic group, and these groups may have a substituent. When there are a plurality of Ar ^DA1 , Ar ^DA2 , Ar ^DA3 , Ar DA4 , Ar ^DA5 , Ar ^DA6 and Ar ^{DA7 ,} they may be the same or different.

T ^DA represents an aryl group or a monovalent heterocyclic group, and these groups may have a substituent. A plurality of T ^DA may be the same or different.

^mDA1 , ^mDA2 , ^mDA3 , ^mDA4 , ^mDA5 , mDA6 and ^mDA7 are preferably integers of 5 or less, more preferably integers of ² or less, and even more preferably 0 or 1. ^mDA2 , ^mDA3 , ^mDA4 , ^mDA5 , ^mDA6 and ^mDA7 are preferably the same integer. ^mDA1 may be an integer of 1 or more and 10 or less.

^G is preferably a group consisting of a benzene ring, a pyridine ring, a pyrimidine ring, a triazine ring, or a carbazole ring, except for three hydrogen atoms that are directly bonded to carbon atoms or nitrogen atoms that constitute the ring, and these groups may have a substituent.

The substituent that G ^DA may have is preferably an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, or a monovalent heterocyclic group, more preferably an alkyl group, a cycloalkyl group, an alkoxy group, or a cycloalkoxy group, and further preferably an alkyl group or a cycloalkyl group, and these groups may have a substituent.

G ^DA is preferably a group represented by formula (GDA-11) to formula (GDA-15), more preferably a group represented by formula (GDA-11) to formula (GDA-14), and even more preferably a group represented by formula (GDA-11) or formula (GDA-14).

[Wherein,
* represents a bond to Ar ^DA1 in formula (DA), Ar ^DA1 in formula (DB), Ar ^DA2 in formula (DB), or Ar ^DA3 in formula (DB).

** represents a bond to Ar ^DA2 in formula (DA), Ar ^DA2 in formula (DB), Ar ^DA4 in formula (DB), or Ar ^DA6 in formula (DB).

*** represents a bond to Ar ^DA3 in formula (DA), Ar ^DA3 in formula (DB), Ar ^DA5 in formula (DB), or Ar ^DA7 in formula (DB).

R ^DA represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an aryl group, or a monovalent heterocyclic group, and these groups may further have a substituent. When there are multiple R ^{DA s} , they may be the same or different.
R ^DA is preferably a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group or a cycloalkoxy group, more preferably a hydrogen atom, an alkyl group or a cycloalkyl group, and these groups may have a substituent.

Ar ^DA1 , Ar ^DA2 , Ar ^DA3 , Ar ^DA4 , Ar ^DA5 , Ar ^DA6 and Ar ^DA7 are preferably a phenylene group, a fluorenediyl group or a carbazolediyl group, more preferably a group represented by formula (ArDA-1) to formula (ArDA-5), further preferably a group represented by formula (ArDA-1) to formula (ArDA-3), particularly preferably a group represented by formula (ArDA-1) or formula (ArDA-2), particularly preferably a group represented by formula (ArDA-2), and these groups may have a substituent.

[Wherein,
R ^DA has the same meaning as defined above.

R ^DB represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, and these groups may have a substituent. When there are multiple R ^DBs , they may be the same or different.

R ^DB is preferably an alkyl group, a cycloalkyl group, an aryl group, or a monovalent heterocyclic group, more preferably an aryl group or a monovalent heterocyclic group, and even more preferably an aryl group, and these groups may have a substituent.

Examples and preferred ranges of the substituents which Ar ^DA1 , Ar ^DA2 , Ar ^DA3 , Ar ^DA4 , Ar ^DA5 , Ar ^DA6 and Ar ^DA7 may have are the same as the examples and preferred ranges of the substituents which G ^DA may have.

^TDA is preferably a group represented by formula (TDA-1) to formula (TDA-3), more preferably a group represented by formula (TDA-1).

［式中、Ｒ^DA及びＲ^DBは、前記と同じ意味を表す。］

[In the formula, R ^DA and R ^DB have the same meanings as defined above.]

The group represented by formula (D-A) is preferably a group represented by formula (D-A1) to formula (D-A5), more preferably a group represented by formula (D-A1) or formula (D-A3) to formula (D-A5), and even more preferably a group represented by formula (D-A1), formula (D-A3) or formula (D-A5).

The group represented by formula (D-B) is preferably a group represented by formula (D-B1) to formula (D-B6), more preferably a group represented by formula (D-B1) to formula (D-B3), formula (D-B5) or formula (D-B6), even more preferably a group represented by formula (D-B1), formula (D-B3) or formula (D-B5), and particularly preferably a group represented by formula (D-B1).

Examples of the group represented by formula (D-A) include groups represented by formulas (D-A-1) to (D-A-12).

［式中、Ｒ^Dは、水素原子、メチル基、エチル基、イソプロピル基、ｔｅｒｔ－ブチル基、ヘキシル基、２－エチルヘキシル基、ｔｅｒｔ－オクチル基、シクロヘキシル基、メトキシ基、２－エチルヘキシルオキシ基又はシクロへキシルオキシ基を表す。Ｒ^Dが複数存在する場合、それらは同一でも異なっていてもよい。］

[In the formula, ^R represents a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a hexyl group, a 2-ethylhexyl group, a tert-octyl group, a cyclohexyl group, a methoxy group, a 2-ethylhexyloxy group, or a cyclohexyloxy group. When there are a plurality of ^Rs , they may be the same or different.]

Examples of the group represented by formula (D-B) include groups represented by formulas (D-B-1) to (D-B-7).

［式中、Ｒ^Dは、水素原子、メチル基、エチル基、イソプロピル基、ｔｅｒｔ－ブチル基、ヘキシル基、２－エチルヘキシル基、ｔｅｒｔ－オクチル基、シクロヘキシル基、メトキシ基、２－エチルヘキシルオキシ基又はシクロへキシルオキシ基を表す。Ｒ^Dが複数存在する場合、それらは同一でも異なっていてもよい。］

[In the formula, ^R represents a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a hexyl group, a 2-ethylhexyl group, a tert-octyl group, a cyclohexyl group, a methoxy group, a 2-ethylhexyloxy group, or a cyclohexyloxy group. When there are a plurality of ^Rs , they may be the same or different.]

R ^D is preferably a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a hexyl group, a 2-ethylhexyl group, or a tert-octyl group.

In this specification, unless otherwise specified, examples of "substituents" include halogen atoms, cyano groups, alkyl groups, cycloalkyl groups, alkoxy groups, cycloalkoxy groups, alkylthio groups, cycloalkylthio groups, aryl groups, aryloxy groups, arylthio groups, arylalkyl groups, arylalkoxy groups, arylalkylthio groups, acyl groups, acyloxy groups, amide groups, acid imide groups, imine residues, substituted amino groups, substituted silyl groups, substituted silyloxy groups, substituted silylthio groups, substituted silylamino groups, monovalent heterocyclic groups, heteroaryloxy groups, heteroarylthio groups, arylalkenyl groups, arylalkynyl groups, substituted carboxyl groups, cyano groups, and dendrons. The substituents may be bridging groups.

2. Method for Producing an Iridium Dinuclear Complex The method for producing an iridium dinuclear complex represented by formula (1) of this embodiment is characterized in that iridium chloride is reacted with a compound represented by formula (2) in an alkoxy alcohol without adding water. That is, the method is characterized in that iridium chloride is reacted with a compound represented by formula (2) in an alkoxy alcohol under conditions substantially free of water.

The compounds represented by formula (2) can be produced according to or in accordance with known methods. For example, they can be synthesized by Suzuki coupling, Grignard coupling, Stille coupling, etc., of a 2-phenylpyridine derivative and a cyclic aromatic compound or a heterocyclic aromatic compound. More specifically, they can be synthesized by dissolving these compounds in an organic solvent as necessary and reacting them at a temperature between the melting point and the boiling point of the organic solvent using, for example, an alkali or a suitable catalyst. For this synthesis, for example, the methods described in "Organic Syntheses", Collective Volume VI, pp. 407-411, John Wiley & Sons, Inc., 1988; Chem. Rev., Vol. 106, p. 2651 (2006); Chem. Rev., Vol. 102, p. 1359 (2002); Chem. Rev., Vol. 95, p. 2457 (1995); Journal of Organometallic Chemistry, Vol. 576, p. 147 (1999), etc. can be used.

The heterocyclic aromatic compounds can be synthesized by the methods described in "HOUBEN-WEYL METHODS OF ORGANIC CHEMISTRY 4T H EDITION", Vol. E9b, p. 1, GEORG THIEME VERLAG STUTTGART; HOUBEN-WEYL METHODS OF ORGANIC CHEMISTRY 4T H EDITION, Vol. E9c, p. 667, GEORG THIEME VERLAG STUTTGART, etc.

In this embodiment, the reaction temperature is the external temperature of the reaction vessel, which is usually 110°C or higher, preferably 115°C or higher, more preferably 115 to 250°C, and even more preferably 115 to 200°C. Alternatively, it is preferably 120°C or higher, more preferably 120 to 200°C, and even more preferably 130 to 160°C. The internal temperature of the reaction vessel is usually 110°C or higher, preferably 115°C or higher, more preferably 115 to 250°C, and even more preferably 115 to 200°C. Alternatively, it is preferably 120°C or higher, more preferably 120 to 200°C, and even more preferably 130 to 160°C. Here, the internal temperature refers to the temperature of the solution or suspension in the reaction vessel, and the external temperature refers to the temperature of a heat medium such as an oil bath that heats the reaction vessel from the outside.

The reaction time is usually 1 minute to 3 hours, preferably 5 minutes to 2 hours. The reaction time means the time from the start of the reaction to the end (stop) of the reaction. The time when the reaction is ended (stopped) is the time when the LC area percentage value of the iridium dinuclear complex stops changing when the reaction solution is sampled multiple times at regular time intervals (for example, 1 minute to 3 hour intervals) and analyzed by liquid chromatography (LC). Specifically, the method described in the Examples can be adopted. After the reaction is completed, the iridium dinuclear complex represented by formula (1) can be obtained using a known method.

In this reaction, an alkoxy alcohol is used as a solvent, and reaction conditions that do not substantially contain water are adopted, so that the reaction temperature can be increased to above the boiling point of water, but since water is not contained, it was expected that the solubility of iridium chloride in the solvent would be low, and the reaction would be slow. However, by reacting a compound represented by formula (2) having a specific structure (wherein at least one of R ¹ and R ² has a halogen atom, an alkyl group, or a group represented by formula (3)) with iridium chloride under the above reaction conditions, contrary to the above expectation, the reaction is dramatically promoted, and it has become clear that the iridium dinuclear complex represented by formula (1) can be produced in a short time. In addition, by shortening the reaction time, the amount of by-products is reduced, and the yield of the iridium dinuclear complex represented by formula (1) is also improved.

The solvent used in this reaction is an alkoxy alcohol. The alkoxy alcohol refers to an alcohol having an alkoxy group, and examples thereof include those having a boiling point of 120°C or higher, preferably 120°C to 350°C, and more preferably 120°C to 210°C at normal pressure. Preferred are alkoxy alcohols having 3 or more carbon atoms, more preferably alkoxy alcohols having 3 to 12 carbon atoms, and even more preferably alkoxy alcohols having 3 to 6 carbon atoms. Specific examples include C2-C3 alkylene glycol mono C1-4 alkyl ethers such as 2-methoxyethanol, 2-ethoxyethanol, 2-n-propoxyethanol, 2-isopropoxyethanol, 2-n-butoxyethanol, 2-isobutoxyethanol, 2-sec-butoxyethanol, 2-tert-butoxyethanol, 1,3-propanediol monomethyl ether, 1,3-propanediol monoethyl ether, and propylene glycol 1-monomethyl ether; di(C2-C3 alkylene glycol) mono C1-4 alkyl ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether (carbitol), and dipropylene glycol monomethyl ether; and poly(particularly tri- or tetra-)(C2-C3 alkylene glycol) mono C1-4 alkyl ethers such as triethylene glycol monomethyl ether and tetraethylene glycol monomethyl ether. Of these, 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-butoxyethanol, carbitol, dipropylene glycol monomethyl ether, triethylene glycol monomethyl ether, etc. are preferred.

From the viewpoint of the fluidity of the reaction solution, the amount of alkoxy alcohol used (volume v: ml) is, for example, 10 times (v/w) or more, preferably 30 times (v/w) or more, more preferably 30 to 85 times (v/w) the pure content of iridium chloride (mass w: g). Here, the pure content of iridium chloride means iridium chloride or a salt thereof excluding water of the hydrate when iridium chloride is a hydrate. Alternatively, the amount of alkoxy alcohol used can be set so that the molar concentration of the pure content of iridium chloride is, for example, 0.30 mol/l or less, preferably 0.02 to 0.20 mol/l, more preferably 0.03 to 0.15 mol/l.

The solvent used in this reaction may contain, in addition to the alkoxy alcohol, other organic solvents within a range that does not adversely affect the effects of the present invention. Examples of such other organic solvents include those having a boiling point of 120°C or higher at normal pressure (e.g., 1 atm). Examples include n-octane, n-nonane, n-decane, xylene, monochlorobenzene, o-dichlorobenzene, dimethylformamide, dimethyl sulfoxide, 1-pentanol, 1-octanol, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diethylene glycol, and triethylene glycol. The solvent preferably contains an alkoxy alcohol as a main component, and the content of the alkoxy alcohol in the total solvent is usually 80% by volume or more, preferably 90% by volume or more, more preferably 95% by volume or more, and particularly preferably 98% by volume or more.

This reaction is carried out by mixing the above-described alkoxy alcohol, iridium chloride, and the compound represented by formula (2), but there is no particular restriction on the order in which they are added to the reaction system, and they may be added in any order.

In the present invention, the reaction is carried out without adding water to the reaction system containing the above-mentioned solvent, iridium chloride, and the compound represented by formula (2). In other words, the reaction is carried out under conditions that are substantially free of water in the reaction system containing the above-mentioned solvent, iridium chloride, and the compound represented by formula (2). This allows the reaction to proceed quickly, and the reaction time for forming the iridium binuclear complex represented by formula (1) is significantly shortened. Here, "substantially free of water" means that the water content is reduced as much as possible so that the internal temperature of the reaction vessel is unlikely to rise above the boiling point of water, which would cause the reaction to be delayed, and does not mean that the reaction system is completely free of water. The content of water that can be contained in the reaction system is usually 5% by mass or less, preferably 2% by mass or less, more preferably 1% by mass or less, and particularly preferably less than 1% by mass, in the total solvent. In addition, when a hydrate of iridium chloride is used in the production method of the present invention, the amount of water generated from the hydrate is small, so that it does not usually have a negative effect on the effects of the present invention. Therefore, water derived from the hydrate of iridium chloride is not included in the water added to the reaction system in this reaction.

The iridium chloride used in this reaction includes anhydrous iridium chloride, its salts, or hydrates thereof. The iridium contained in the iridium chloride is preferably trivalent. Specifically, examples of the iridium chloride include iridium(III) chloride, iridium(III) chloride monohydrate, iridium(III) chloride dihydrate, iridium(III) chloride trihydrate, iridium(III) chloride n-hydrate, anhydrous or n-hydrate of sodium chloroiridate(III) (Na ₃ [IrCl ₆ ]), anhydrous or n-hydrate of potassium chloroiridate(III) (K ₃ [IrCl ₆ ]), and anhydrous or n-hydrate of ammonium chloroiridate(III) ((NH ₄ ) ₃ [IrCl ₆ ]) (n is a number greater than 0).

Preferred embodiments of the iridium dinuclear complex represented by formula (1) and the compound represented by formula (2) include the following.

R ³ to R ⁸ are preferably a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an arylalkyl group, a substituted amino group, a monovalent heterocyclic group, or a dendron (these groups may have a substituent). Further, R ⁵ to R ⁸ are preferably a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an arylalkyl group, a monovalent heterocyclic group, or a dendron (these groups may have a substituent).

It is also preferred that two adjacent groups among R ³ to R ⁸ are bonded to each other to form a ring together with the carbon atoms to which they are bonded (this formed ring may further have a substituent).It is also preferred that two adjacent groups among R ⁵ to R ⁸ are bonded to each other to form a ring together with the carbon atoms to which they are bonded (this formed ring may further have a substituent).

One of ^R1 and ^R2 is preferably a halogen atom, an alkyl group, or a group represented by formula (3), more preferably a halogen atom or a group represented by formula (3), and even more preferably a group represented by formula (3). The other of ^R1 and ^R2 is preferably a hydrogen atom.

It is preferred that ^R2 is a halogen atom, an alkyl group, or a group represented by formula (3), and ^R1 is a hydrogen atom. It is more preferred that ^R2 is a halogen atom, or a group represented by formula (3), and ^R1 is a hydrogen atom. It is particularly preferred that ^R2 is a group represented by formula (3), and ^R1 is a hydrogen atom.

The halogen atom is preferably a chlorine atom or a bromine atom, and more preferably a bromine atom.

The alkyl group is preferably an alkyl group having 1 to 12 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. The alkyl group may be either linear or branched.

The cycloalkyl group is preferably a cycloalkyl group having 3 to 12 carbon atoms, and more preferably a cycloalkyl group having 5 to 10 carbon atoms.

In the group represented by formula (3), it is preferred that two or more A's are =N-, or that all A's are =CH-, and that =CH-'s may have a substituent. Furthermore, it is particularly preferred that all A's are =N-, or that all A's are =CH-, and that =CH-'s may have a substituent.

In this reaction, the amount of the compound represented by formula (2) used is usually 2 moles or more, preferably 2.1 moles or more, and more preferably 2.2 moles or more, per mole of iridium chloride.

More preferred embodiments of the iridium dinuclear complex represented by formula (1) and the compound represented by formula (2) include the iridium dinuclear complex represented by formula (1A) and the compound represented by formula (2A).

（式中、Ｒ^１、Ｒ^２、Ｒ^６及びＲ^７は、前記に同じ。）

(In the formula, R ¹ , R ² , R ⁶ and R ⁷ are the same as above.)

Examples of the metal complex represented by the above formula (1A) include the metal complexes shown below.

The iridium dinuclear complex obtained by the manufacturing method of this embodiment is used as a synthetic intermediate for a light-emitting material (iridium complex) used in the light-emitting layer of an organic electroluminescence element. The iridium dinuclear complex can be converted into a light-emitting material (iridium complex) by a known method (for example, Patent Document 1, etc.).

3. Method for Producing Iridium Complex The iridium complex represented by formula (5) of this embodiment is obtained by reacting the dinuclear iridium complex represented by formula (1) obtained above with a compound represented by formula (4).

In this embodiment, the reaction temperature is the external temperature of the reaction vessel, which is usually 80°C or higher, preferably 80 to 200°C, more preferably 90 to 180°C, and even more preferably 100 to 160°C. The internal temperature of the reaction vessel is usually 80°C or higher, preferably 80°C or higher, more preferably 90 to 180°C, and even more preferably 100 to 160°C. Here, the internal temperature refers to the temperature of the solution or suspension in the reaction vessel, and the external temperature refers to the temperature of a heat medium such as an oil bath that heats the reaction vessel from the outside.

The reaction time is usually 1 hour or more, preferably 1 to 100 hours, more preferably 1 to 50 hours, and even more preferably 1 to 10 hours.

This reaction is usually carried out in a solvent. Examples of the solvent include alcohol solvents such as methanol, ethanol, propanol, ethylene glycol, glycerin, 2-methoxyethanol, 2-ethoxyethanol, and 2-butoxyethanol; ether solvents such as diethyl ether, tetrahydrofuran, dioxane, cyclopentyl methyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, 1,4-dioxane, and 4-methyltetrahydropyran; halogenated hydrocarbon solvents such as methylene chloride, chloroform, monochlorobenzene, and o-dichlorobenzene; nitrile solvents such as acetonitrile and benzonitrile; hydrocarbon solvents such as n-hexane, n-heptane, n-octane, decalin, toluene, xylene, and mesitylene; amide solvents such as N,N-dimethylformamide and N,N-dimethylacetamide; acetone, dimethyl sulfoxide, and water. Ether solvents and alcohol solvents are preferred, and ether solvents are more preferred.

The ether solvent is preferably dioxane, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, or triethylene glycol dimethyl ether, and more preferably diethylene glycol dimethyl ether.

From the viewpoint of the fluidity of the reaction solution, the amount of the solvent used (volume v: ml) is, for example, 3 times (v/w) or more, preferably 5 times (v/w) or more, and more preferably 10 to 25 times (v/w) the pure content (mass w: g) of the compound represented by formula (1).

The solvent used in this reaction preferably contains an ether solvent and/or an alcohol solvent as a main component, and the content of the solvent and/or alcohol solvent in the total solvent is usually 80% by volume or more, preferably 90% by volume or more, more preferably 95% by volume or more, and particularly preferably 98% by volume or more.

This reaction can be carried out by mixing the above-described solvent, the compound represented by formula (1), the compound represented by formula (4), a silver compound, and, if necessary, a base. There is no particular restriction on the order in which these components are added to the reaction system, and they may be added in any order.

The silver compound used in this reaction is preferably, for example, silver trifluoromethanesulfonate, silver trifluoroacetate, etc., and more preferably silver trifluoromethanesulfonate.

This reaction may or may not involve the use of a base, but it is preferable to use a base. The base used may be either an organic base or an inorganic base, but is preferably an organic base. Examples of organic bases include ammonia, triethylamine, and 2,6-lutidine, with 2,6-lutidine being preferred.

Preferred embodiments of the iridium complex represented by formula (5) include the following.
R ³ to R ⁸ are preferably a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an arylalkyl group, a substituted amino group, a monovalent heterocyclic group, or a dendron (these groups may have a substituent). Further, R ⁵ to R ⁸ are preferably a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an arylalkyl group, a monovalent heterocyclic group, or a dendron (these groups may have a substituent).

Furthermore, two adjacent groups among ^R3 to ^R8 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded (this ring may further have a substituent). Furthermore, two adjacent groups among ^R5 to ^R8 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded (this ring may further have a substituent).

One of ^R1 and ^R2 is preferably a halogen atom, an alkyl group, or a group represented by formula (3), more preferably a halogen atom or a group represented by formula (3), and even more preferably a group represented by formula (3). The other of ^R1 and ^R2 is preferably a hydrogen atom.

It is preferred that ^R2 is a halogen atom, an alkyl group, or a group represented by formula (3), and ^R1 is a hydrogen atom. It is more preferred that ^R2 is a halogen atom, or a group represented by formula (3), and ^R1 is a hydrogen atom. It is particularly preferred that ^R2 is a group represented by formula (3), and ^R1 is a hydrogen atom.

The halogen atom is preferably a chlorine atom or a bromine atom, and more preferably a bromine atom.

The alkyl group is preferably an alkyl group having 1 to 12 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. The alkyl group may be either linear or branched.

The cycloalkyl group is preferably a cycloalkyl group having 3 to 12 carbon atoms, and more preferably a cycloalkyl group having 5 to 10 carbon atoms.

In the group represented by formula (3), it is preferred that two or more A's are =N-, or that all A's are =CH-, and that =CH-'s may have a substituent. Furthermore, it is particularly preferred that all A's are =N-, or that all A's are =CH-, and that =CH-'s may have a substituent.

R ¹³ to R ¹⁸ are preferably a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an arylalkyl group, a substituted amino group, a monovalent heterocyclic group, or a dendron (these groups may have a substituent). Further, R ¹⁵ to R ¹⁸ are preferably a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an arylalkyl group, a monovalent heterocyclic group, or a dendron (these groups may have a substituent).

Furthermore, two adjacent groups among R ¹³ to R ¹⁸ may be bonded to each other to form a ring together with the carbon atoms to which they are bonded (this ring may further have a substituent). Furthermore, two adjacent groups among R ¹⁵ to R ¹⁸ may be bonded to each other to form a ring together with the carbon atoms to which they are bonded (this ring may further have a substituent).

［式中、
Ａ^１は、＝ＣＨ－又は＝Ｎ－を表し、Ａ^１が＝ＣＨ－である場合は置換基を有していてもよく、Ａ^１が＝Ｎ－である場合は２つ以上のＡ^１が＝Ｎ－である。複数存在するＡ^１は、同一でも異なっていてもよい。
Ｒ^１９及びＲ^２０は、それぞれ独立に、水素原子、ハロゲン原子、アルキル基、シクロアルキル基、アルコキシ基、シクロアルコキシ基、アルキルチオ基、シクロアルキルチオ基、アリール基、アリールオキシ基、アリールチオ基、アリールアルキル基、アリールアルコキシ基、アリールアルキルチオ基、アシル基、アシルオキシ基、アミド基、酸イミド基、イミン残基、置換アミノ基、置換シリル基、置換シリルオキシ基、置換シリルチオ基、置換シリルアミノ基、１価の複素環基、ヘテロアリールオキシ基、ヘテロアリールチオ基、アリールアルケニル基、アリールアルキニル基、置換カルボキシル基、シアノ基、又はデンドロンを表し、これらの基は置換基を有していてもよい。］ One of R ¹¹ and R ¹² is preferably a halogen atom, an alkyl group, or a group represented by formula (6), more preferably a halogen atom or a group represented by formula (6), and even more preferably a group represented by formula (6). The other of R ¹¹ and R ¹² is preferably a hydrogen atom.

[Wherein,
A ¹ represents =CH- or =N-, and when A ¹ is =CH-, it may have a substituent, and when A ¹ is =N-, two or more A ¹ are =N-. A ¹ present multiple times may be the same or different.
R ¹⁹ and R ²⁰ each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, a cyano group, or a dendron, and these groups may have a substituent.]

It is preferable that R ¹² is a halogen atom, an alkyl group, or a group represented by formula (6), and R ¹¹ is a hydrogen atom. It is more preferable that R ¹² is a halogen atom, or a group represented by formula (6), and R ¹¹ is a hydrogen atom. It is particularly preferable that R ¹² is a group represented by formula (6), and R ¹¹ is a hydrogen atom.

The halogen atom is preferably a chlorine atom or a bromine atom, and more preferably a bromine atom.

The alkyl group is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. The alkyl group may be either linear or branched.
The cycloalkyl group is preferably a cycloalkyl group having 3 to 12 carbon atoms, and more preferably a cycloalkyl group having 5 to 10 carbon atoms.

In the group represented by formula (6), it is preferred that two or more A ¹ 's are =N-, or all A ¹ 's are =CH-, which may have a substituent. It is particularly preferred that all A ¹ 's are =N-, or all A ¹ 's are =CH-, which may have a substituent.

In this reaction, the amount of the compound represented by formula (4) used is usually 2 to 20 mol, preferably 2 to 10 mol, more preferably 2 to 3 mol, relative to 1 mol of the compound represented by formula (1).
In this reaction, the amount of the silver compound used is usually 2 to 20 moles, preferably 2 to 10 moles, and more preferably 2 to 3 moles, per mole of the compound represented by formula (1).
In the case where a base is used in this reaction, the amount of the base used is usually 2 to 20 mol, preferably 2 to 10 mol, more preferably 2 to 3 mol, relative to 1 mol of the compound represented by formula (1).

（式中、Ｒ^１、Ｒ^２、Ｒ^６、Ｒ^７、Ｒ^１１、Ｒ^１２、Ｒ^１６、及びＲ^１７は、前記に同じ。） A preferred embodiment of the iridium complex represented by formula (5) is an iridium complex represented by formula (1C), and a more preferred embodiment is an iridium complex represented by formula (1C) in which R ¹ = R ¹¹ , R ² = R ¹² , R ⁶ = R ¹⁶ , and R ⁷ = R ¹⁷ .

(In the formula, R ¹ , R ² , R ⁶ , R ⁷ , R ¹¹ , R ¹² , R ¹⁶ , and R ¹⁷ are the same as above.)

Specific examples of the metal complex represented by the above formula (1C) include the metal complexes shown below.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. As an index of the purity of a compound, the value of the area percentage of high performance liquid chromatography (HPLC) was used. This value is the value at UV=254 nm in HPLC (manufactured by Shimadzu Corporation, product name: LC-20A) unless otherwise specified. In this case, the compound to be measured was dissolved in toluene or chloroform so as to have a concentration of 0.01 to 0.2 mass%, and 1 to 10 μL was injected into the HPLC depending on the concentration. The mobile phase of the HPLC was used with a ratio of acetonitrile/tetrahydrofuran changed from 100/0 to 0/100 (volume ratio), and the flow rate was 1.0 mL/min. The column used was SUMIPAX ODS Z-CLUE (manufactured by Sumika Chemical Analysis Center) or an ODS column having equivalent performance. The detector used was a photodiode array detector (manufactured by Shimadzu Corporation, product name: SPD-M20A).

<Synthesis Example 1> (Compound L-1)
Compound L-1 described below was synthesized according to the method described in JP-A-2016-64998.

<Synthesis Example 2> (Compound L-2)
Compound L-2a (5-bromo-2-(4-tert-butylphenyl)pyridine) was synthesized according to the method described in Japanese Patent No. 5128728. Methyl-2-(2'-methyl-4,4''-bis(2,4,4-trimethylpentan-2-yl)-[1,1':3',1''-terphenyl]-5 -yl)-1,3,2-dioxaborolane) was synthesized according to the method described in JP 2014-224101 A.

Compound L-2a (14.8 g, 51.2 mmol), compound L-2b (31.3 g, 52.7 mmol), tetrakistriphenylphosphine palladium (0.230 g, 1.02 mmol), 40% by mass tetrabutylammonium hydroxide aqueous solution (132 g, 205 mmol), and toluene (148 mL) were weighed into a reaction vessel, and the mixture was stirred at 85° C. for 1 hour under a nitrogen atmosphere. After cooling to room temperature, the mixture was separated and the organic layer was recovered. Ion-exchanged water was added to the organic layer, and washing with water was repeatedly performed until the pH became 8. After drying with anhydrous magnesium sulfate, activated carbon (2.97 g) was added and the mixture was stirred for 30 minutes. The resulting mixture was filtered through silica gel Celite, washed with toluene, and then concentrated to dryness. Toluene (59.4 ml) was added to the concentrated residue, and the mixture was dissolved by heating at 75° C. After adjusting the temperature to 55° C., acetonitrile (178 ml) was added dropwise, and the mixture was stirred for 1 hour, and then cooled to 0° C. The precipitated white solid was collected by filtration, washed with a mixed solvent of toluene:acetonitrile (1:3), and dried to obtain crude crystals. Toluene (125 ml) was added to the obtained crude crystals, and the mixture was heated and dissolved at 75°C. After adjusting the temperature to 55°C, acetonitrile (376 ml) was added dropwise, and the mixture was kept at 55°C for 1 hour, and then cooled to 0°C. The precipitated white solid was collected by filtration, washed with a mixed solvent of toluene:acetonitrile (1:3), and dried to obtain compound L-2 (30.4 g, 44.8 mmol) in a yield of 88%.
¹ H-NMR (CDCl ₃ , 300MHz): δ (ppm) = 0.75 (s, 18H), 1.37 (s, 9H), 1.44 (s, 12H), 1.77 (s, 4H), 2. 14 (s, 3H), 7.31-7.51 (m, 12H), 7.76 (d, 1H), 7.95-8.00 (m, 3H), 8.96 (d, 1H))

<Synthesis Example 3> (Compound L-3)
Compound L-3a (5-bromo-2-phenylpyridine) was a commercially available reagent (manufactured by Tokyo Chemical Industry Co., Ltd.) Compound L-3b was synthesized according to the method described in JP 2011-195829 A.

Compound L-3a (12.8 g, 54.6 mmol), compound L-3b (30.7 g, 65.5 mmol), potassium phosphate (20.9 g, 98.3 mmol), bis(triphenylphosphine)palladium dichloride (38.3 mg, 0.0546 mmol), ion-exchanged water (19.2 ml), n-butanol (94.6 ml), and toluene (29.4 mL) were weighed into a reaction vessel, and the mixture was stirred at 80° C. for 3 hours under a nitrogen atmosphere. After cooling to room temperature, toluene (76.7 ml) was added to the reaction solution, which was stirred and separated to recover the organic layer. Ion-exchanged water (25.6 ml) was added to the organic layer, which was stirred and separated, and the organic layer was concentrated. Toluene (162.6 ml) was added to the concentrated residue, and the mixture was dissolved by heating. n-heptane (65.0 ml) was added dropwise to this solution, which was then cooled to room temperature. The precipitated white solid was collected by filtration, washed with n-heptane, and dried to obtain compound L-3 (11.72 g, 24.8 mmol).
¹ H-NMR (CDCl ₃ , 300MHz): δ (ppm) = 1.39 (s, 18H), 7.44-7.55 (m, 7H), 7.63-7.67 (m, 4H), 7.79 (d, 2H), 7.83-7.86 (m, 2H), 8.03-8.10 (m, 3H), 9.03 (dd, 1H)

<Synthesis Example 4> (Compound L-4)
Compound L-4 was synthesized according to the method described in JP 2012-36388 A.

<Synthesis Example 5> (Compound CL-1)
Compound CL-1 was synthesized according to the method described in JP 2012-131995 A.

(Compound L-6)
Compound L-6 (2,6-diphenylpyridine) was a commercially available reagent (Tokyo Chemical Industry Co., Ltd.).

(Compound L-7)
Compound L-7 (2-methyl-6-phenylpyridine) was a commercially available reagent (Tokyo Chemical Industry Co., Ltd.).

(Compound L-8)
Compound L-8 (5-methyl-2-phenylpyridine) was a commercially available reagent (Tokyo Chemical Industry Co., Ltd.).

(Compound L-9)
Compound L-9 (2-bromo-6-phenylpyridine) was a commercially available reagent (Tokyo Chemical Industry Co., Ltd.).

(Compound L-11)
Compound L-11 (4-bromo-2-phenylpyridine) was a commercially available reagent (manufactured by AstaTech).

Example 1 (Synthesis of compound M-1 without adding water)
Compound L-1 (3.14 g, 3.73 mmol), iridium chloride n-hydrate (0.619 g, 1.67 mmol), and 2-ethoxyethanol (41.7 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 150° C. (internal temperature 132° C.). The water content at the start of the reaction was 0.3 mass %. The reaction was stopped 40 minutes after the start of the reaction. The LC analysis value of compound M-1 at 40 minutes was 60% (area percentage value).

The reaction solution was sampled at least twice at 10-minute intervals and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Example 2 (Synthesis of compound M-1 without adding water)
Compound L-1 (0.940 g, 1.12 mmol), iridium chloride n-hydrate (0.180 g, 0.500 mmol), and 2-butoxyethanol (12.5 mL) were weighed out and placed in a reaction vessel, and heated at an external temperature of 150° C. under a nitrogen stream. The water content at the start of the reaction was 0.3 mass %. The reaction was stopped 50 minutes after the start of the reaction. The LC analysis value of compound M-1 at 50 minutes was 71% (area percentage value).

The reaction solution was sampled at least twice at intervals of 10 to 40 minutes and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Comparative Example 1 (Synthesis of Compound M-1 by Addition of Water)
Compound L-1 (6.25 g, 7.44 mmol), iridium chloride n-hydrate (1.24 g, 3.35 mmol), 2-ethoxyethanol (83.3 mL), and water (13.3 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 150° C. (internal temperature of 109° C.). The water content at the start of the reaction was 13.8% by mass. The reaction was not completed 48 hours after the start of the reaction. The LC analysis value of compound M-1 at 48 hours was 29% (area percentage value).

Sampling was carried out at intervals of 3.5 to 15 hours.

Example 3 (Synthesis of compound M-2 without adding water)
Compound L-2 (2.00 g, 2.95 mmol), iridium chloride n-hydrate (0.495 g, 1.34 mmol), and 2-ethoxyethanol (12.0 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 152° C. (internal temperature of 130° C.). The water content at the start of the reaction was 0.6% by mass. The reaction was stopped 1.5 hours after the start of the reaction. The LC analysis value of compound M-2 at 1.5 hours was 82% (area percentage value).
The reaction solution was sampled at least twice at intervals of 15 to 30 minutes and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Example 4 (Synthesis of compound M-3 without adding water)
Compound L-3 (0.943 g, 1.86 mmol), iridium chloride n-hydrate (0.31 g, 0.837 mmol), and 2-ethoxyethanol (17.5 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 150° C. (internal temperature of 135° C.). The water content at the start of the reaction was 0.3 mass %. The reaction was stopped one hour after the start of the reaction. The LC analysis value of compound M-3 at one hour was 68% (area percentage value).

The reaction solution was sampled at least twice at 15-30 minute intervals and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Example 5 (Synthesis of compound M-4 without adding water)
Compound L-4 (2.13 g, 4.27 mmol), iridium chloride n-hydrate (0.686 g, 1.92 mmol), and 2-ethoxyethanol (17.2 mL) were weighed out and placed in a reaction vessel, and heated at an external temperature of 150° C. under a nitrogen stream. The water content at the start of the reaction was 0.6 mass %. The reaction was stopped 35 minutes after the start of the reaction. The LC analysis value of compound M-4 at 35 minutes was 78% (area percentage value).

The reaction solution was sampled at least twice at 25-30 minute intervals and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Example 6 (Synthesis of compound M-4 without adding water)
Compound L-4 (2.13 g, 4.27 mmol), iridium chloride n-hydrate (0.686 g, 1.92 mmol), and 2-butoxyethanol (17.2 mL) were weighed out and placed in a reaction vessel, and heated at an external temperature of 150° C. under a nitrogen stream. The water content at the start of the reaction was 0.6% by mass. The reaction was stopped 35 minutes after the start of the reaction. The LC analysis value of compound M-4 at 35 minutes was 74% (area percentage value).

The reaction solution was sampled at least twice at 25-30 minute intervals and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Example 7 (Synthesis of compound M-4 without adding water)
Compound L-4 (1.85 g, 3.72 mmol), iridium chloride n-hydrate (0.619 g, 1.67 mmol), and carbitol (15.0 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 150° C. (internal temperature 132° C.). The water content at the start of the reaction was 0.7% by mass. The reaction was stopped 10 minutes after the start of the reaction. The LC analysis value of compound M-4 at 10 minutes was 76% (area percentage value).

The reaction solution was sampled at least twice at 10-minute intervals and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Example 8 (Synthesis of compound M-6 without adding water)
Compound L-6 (1.00 g, 4.33 mmol), iridium chloride n-hydrate (0.720 g, 1.95 mmol), and 2-ethoxyethanol (40.7 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 156° C. (internal temperature of 133° C.). The water content at the start of the reaction was 0.4% by mass. The reaction was stopped one hour after the start of the reaction. The LC analysis value of compound M-6 at one hour was 24% (area percentage value).
The reaction solution was sampled at least twice at intervals of 15 to 30 minutes and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Example 9 (Synthesis of compound M-7 without adding water)
Compound L-7 (0.98 g, 5.79 mmol), iridium chloride n-hydrate (0.779 g, 2.61 mmol), and 2-ethoxyethanol (54.5 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 150° C. (internal temperature 118° C.). The water content at the start of the reaction was 0.4 mass %. The reaction was stopped 45 minutes after the start of the reaction. The LC analysis value of compound M-7 at 45 minutes was 22% (area percentage value).
The reaction solution was sampled at least twice at intervals of 15 to 30 minutes and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Example 10: Synthesis of compound M-8 without adding water
Compound L-8 (0.98 g, 5.79 mmol), iridium chloride n-hydrate (0.779 g, 2.61 mmol), and 2-ethoxyethanol (54.5 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 152° C. (internal temperature of 132° C.). The water content at the start of the reaction was 0.4% by mass. The reaction was stopped one hour after the start of the reaction. The LC analysis value of compound M-8 at one hour was 39% (area percentage value).
The reaction solution was sampled at least twice at intervals of 15 to 30 minutes and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Example 11 (Synthesis of compound M-9 without adding water)
Compound L-9 (1.00 g, 4.28 mmol), iridium chloride n-hydrate (0.713 g, 1.93 mmol), and 2-ethoxyethanol (40.3 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 157° C. (internal temperature of 130° C.). The water content at the start of the reaction was 0.3 mass %. The reaction was stopped one hour after the start of the reaction. The LC analysis value of compound M-9 at one hour was 48% (area percentage value).
The reaction solution was sampled at least twice at intervals of 15 to 30 minutes and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Example 12 (Synthesis of compound M-10 without adding water)
Compound L-3a (1.00 g, 4.28 mmol), iridium chloride n-hydrate (0.713 g, 1.93 mmol), and 2-ethoxyethanol (40.3 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 154° C. (internal temperature of 133° C.). The water content at the start of the reaction was 0.3 mass %. The reaction was stopped 3 hours after the start of the reaction. The LC analysis value of compound M-10 at 2 hours was 82% (area percentage value).
The reaction solution was sampled at least twice at intervals of 1 to 2 hours and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Example 13 (Synthesis of compound M-11 without adding water)
Compound L-11 (0.93 g, 3.96 mmol), iridium chloride n-hydrate (0.659 g, 1.78 mmol), and 2-ethoxyethanol (37.2 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 151° C. (internal temperature of 137° C.). The water content at the start of the reaction was 0.3 mass %. The reaction was stopped 1.5 hours after the start of the reaction. The LC analysis value of compound M-11 at 1.5 hours was 54% (area percentage value).
The reaction solution was sampled at least twice at intervals of 1 to 2 hours and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Example 14 (Synthesis of compound M-1 without adding water)
Compound L-1 (3.14 g, 3.73 mmol), iridium chloride n-hydrate (0.619 g, 1.67 mmol), and carbitol (41.7 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 203° C. (internal temperature of 191° C.). The water content at the start of the reaction was 0.3 mass %. The reaction was stopped within 1 minute after the start of the reaction. The LC analysis value of compound M-1 immediately after the start of the reaction was 66% (area percentage value).
The reaction solution was sampled at least twice at 15-minute intervals and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Example 15 (Synthesis of compound M-1 without adding water)
Compound L-1 (3.14 g, 3.73 mmol), iridium chloride n-hydrate (0.619 g, 1.67 mmol), and 2-methoxyethanol (41.7 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 154° C. (internal temperature of 125° C.). The water content at the start of the reaction was 0.3 mass %. The reaction was stopped one hour after the start of the reaction. The LC analysis value of compound M-1 at one hour was 60% (area percentage value).
The reaction solution was sampled at least twice at intervals of 15 to 30 minutes and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Comparative Example 2 (Synthesis of compound CM-1 without adding water)
Compound CL-1 (1.85 g, 0.37 mmol), iridium chloride n-hydrate (0.618 g, 1.67 mmol), and 2-ethoxyethanol (35.0 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 150° C. (internal temperature of 135° C.). The water content at the start of the reaction was 0.3 mass %. The reaction was stopped 4 hours after the start of the reaction. The LC analysis value (UV=264 nm) of compound CM-1 after 4 hours was 54% (area percentage value).

The reaction solution was sampled at least twice at 25-60 minute intervals and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when the LC area percentage value of the iridium dinuclear complex no longer changed.

Comparative Example 3 (Synthesis of compound CM-1 with addition of water)
In a reaction vessel, iridium chloride n-hydrate (1.00 g, 2.71 mmol) and water (9.00 mL) were weighed and heated to 60° C. under a nitrogen stream. After confirming the dissolution of iridium chloride, the mixture was cooled to room temperature to prepare an iridium chloride aqueous solution. In a separate reaction vessel, compound CL-1 (2.99 g, 6.04 mmol), 2-ethoxyethanol (70.0 mL), and ion-exchanged water (5.00 mL) were weighed and the iridium chloride aqueous solution was added dropwise over 1 hour under a nitrogen stream at an internal temperature of 100° C. The water content at the end of the dropwise addition was 17.1% by mass. After the dropwise addition, heating was continued at an external temperature of 115° C. (internal temperature of 105° C.), and the reaction stopped after 14 hours. The LC analysis value (UV=264 nm) of compound CM-1 after 14 hours was 82% (area percentage value).

The reaction solution was sampled at least twice at 2-3 hour intervals and analyzed by liquid chromatography (LC). The reaction was determined to have ended (stopped) when there was no change in the LC area percentage value of the iridium dinuclear complex.

Example 16 Synthesis of Compound T-1
Compound L-1 (6.28 g, 7.47 mmol), iridium chloride n-hydrate (1.24 g, 3.35 mmol), and 2-ethoxyethanol (83.3 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 154° C. (internal temperature of 134° C.). The water content at the start of the reaction was 0.3 mass %. The reaction was stopped 45 minutes after the start of the reaction. The LC analysis value of compound M-1 at 45 minutes was 58% (area percentage value).
After the reaction was completed, the reaction mixture was cooled to room temperature and methanol (23 ml) was added dropwise. The precipitated crystals were filtered, washed with methanol (16 ml), and dried under reduced pressure to obtain crude crystals (6.15 g). The obtained crude crystals were purified by silica gel chromatography (toluene: normal heptane = 1:1) to obtain compound M-1 (3.90 g) in a yield of 61%.
¹ H-NMR (CDCl ₃ , 300MHz): δ (ppm) = 1.35 (s, 72H), 2.15 (s, 12H), 6.02 (d, 4H), 6.66 (d, 4H), 6.86 (dd, 4H) ), 7.03 (d, 4H), 7.11-7.57 (m, 80H), 8.44-8.48 (m, 12H), 9.26-9.28 (m, 8H), 11.1 (d, 4H)

Compound M-1 (0.601 g, 1.58 mmol), compound L-1 (0.278 g, 3.31 mmol), AgOTf (0.109 g, 4.25 mmol), 2,6-lutidine (0.0456 g, 4.25 mmol), and diglyme (12.0 mL) were weighed into a reaction vessel, and heated under a nitrogen stream at an external temperature of 158 ° C. (internal temperature 151 ° C.) for 8 hours. After cooling the reaction mixture to room temperature, methanol (27 ml) was added dropwise and stirred for 1 hour. The precipitated crystals were filtered and washed with methanol (4 ml), and the obtained crude crystals were dissolved in toluene (14 ml) and filtered through silica gel Celite. The solid obtained after concentration to dryness was purified by silica gel chromatography (toluene: normal heptane = 7: 3) to obtain compound T-1 (0.42 g) in a yield of 76%.
¹ H-NMR (CDCl ₃ , 300MHz): δ (ppm) = 1.36 (s, 54H), 2.16 (s, 9H), 7.11-7.44 (m, 48H), 7.55 (s, 6H) ), 7.73 (m, 12H), 7.99-8.09 (m, 12H), 8.57 (dd, 3H), 8.79 (d, 6H), 9.93 (dd, 3H)

Example 17 Synthesis of Compound T-2
Compound L-2 (2.66 g, 3.92 mmol), iridium chloride n-hydrate (0.656 g, 1.85 mmol), and 2-ethoxyethanol (16.0 mL) were weighed out and placed in a reaction vessel, and heated under a nitrogen stream at an external temperature of 150° C. (internal temperature of 130° C.). The water content at the start of the reaction was 0.7% by mass. The reaction was stopped one hour after the start of the reaction. The LC analysis value of compound M-2 at one hour was 84% (area percentage value).
After the reaction was completed, the reaction mixture was cooled to room temperature, and ion-exchanged water (5.33 ml) was added dropwise. The precipitated crystals were filtered, washed with methanol (8.00 ml), and dried under reduced pressure to obtain crude crystals. The obtained crude crystals were dissolved in toluene (13.3 ml) and repeatedly washed with water until the pH reached 7. The organic layer was dehydrated with magnesium sulfate (1.60 g), filtered through silica gel Celite, washed with toluene, and the organic solvent was distilled off under reduced pressure. Dichloromethane (11.2 ml) was added to the obtained concentrated residue, heated and dissolved at 50° C., and then methanol (13.8 ml) was added dropwise at 40° C. After keeping at 40° C. for 1 hour, the mixture was cooled to 25° C., and the precipitated crystals were collected by filtration and washed with a mixed solvent of dichloromethane and methanol (2:1). The obtained crystals were dried under reduced pressure to obtain compound M-2 (2.57 g) in a yield of 91%.
¹ H-NMR (CDCl ₃ , 300MHz): δ (ppm) = 0.77 (s, 72H), 0.88 (s, 36H) 1.47 (s, 24H), 1.50 (s, 24H), 1.77 (d, 8H), 1.84 (s, 8H), 2.13 (s, 12H), 5. 99 (d, 4H), 6.73 (dd, 4H), 6.93 (d, 4H), 6.96 (s, 8H), 7.06 (d, 4H), 7.23 (d, 16H), 7.32 (dd, 4H), 7.43 (d, 16H), 9.80 (d, 4H)

Compound M-2 (2.00 g, 0.632 mmol), compound L-2 (1.07 g, 1.58 mmol), AgOTf (0.357 g, 1.39 mmol), 2,6-lutidine (0.169 g, 1.58 mmol), and diglyme (30.0 mL) were weighed into a reaction vessel, and heated under a nitrogen stream at an external temperature of 107 ° C. (internal temperature 102 ° C.) for 6 hours. After cooling the reaction mixture to room temperature, acetonitrile (18.0 ml) was added dropwise, and the precipitated crystals were filtered and washed with acetonitrile (12.0 ml). The obtained crude crystals were dissolved in toluene (40 ml), filtered through silica gel Celite, washed with toluene (16.0 ml), and concentrated to dryness. Toluene (4.20 ml) was added to the concentrated residue, and the mixture was dissolved by heating at 40 ° C., and then acetonitrile (2.00 ml) was added dropwise at 35 ° C. After keeping at 35°C for 1 hour, acetonitrile (4.60 ml) was further added dropwise and stirred for 30 minutes. After cooling to 0°C, the precipitated crystals were filtered, washed with a mixed solvent of toluene and acetonitrile (1:1.6), and dried under reduced pressure to obtain compound T-2 (2.26 g) in a yield of 81%.
¹ H-NMR (CDCl ₃ , 300MHz): δ (ppm) = 0.75 (s, 54H), 1.13 (s, 27H), 1.38 (s, 18H), 1.39 (s, 18H), 1.76 (s, 12H), 1.94 (s, 9H), 6 91-6.95 (m, 9H), 7.09-7.11 (m, 15H), 7.33 (d, 12H), 7.43 (dd, 3H), 7.51 (d, 3H), 7.58 (d, 3H), 7.74 (d, 3H)

The following points became clear from Examples 1 to 17 and Comparative Examples 1 to 3.

When a compound having a substituent at the R ² position in formula (2) (compound L-1) was used as a ligand, the reaction was completed in a short time of less than 1 hour when an alkoxy alcohol was used as a solvent (Examples 1 and 2), whereas when an alkoxy alcohol or water was used as a solvent, the internal temperature did not increase and the reaction was not completed even after 48 hours (Comparative Example 1).

When a compound having no substituent at the ^R2 position in formula (2) (compound CL-1) was used as the ligand and an alkoxy alcohol was used as the solvent, the internal temperature rose to 135° C., but the reaction completion time was 4 hours (Comparative Example 2). On the other hand, when an alkoxy alcohol and water were used as the solvent, the internal temperature did not rise, and the reaction completion time was 14 hours (Comparative Example 3).

When a compound having a substituent at the R ² position in formula (2) (compound L-3 and compound L-4) was used as the ligand, and an alkoxy alcohol was used as the solvent, the reaction was completed in a short time of within 2 hours.

These results demonstrate that the reaction time required to complete the reaction in the production of the iridium dinuclear complex represented by formula (1) can be significantly shortened by reacting a compound having a substituent at the ^R2 position in formula (2) as a ligand with iridium chloride in an alkoxyalcohol without adding water.

The manufacturing method of the present invention can significantly shorten the reaction time when synthesizing an iridium dinuclear complex, which is a synthetic intermediate of a light-emitting material (iridium complex) used in the light-emitting layer of an organic electroluminescence element.

Claims (10)

A method for producing an iridium dinuclear complex represented by formula (1), comprising reacting iridium chloride with a compound represented by formula (2) in an alkoxy alcohol without adding water.

[In formula (1) and formula (2),
R ¹ to R ⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, a cyano group, or a dendron, and these groups may have a substituent. Two adjacent groups among ^{R 3} to R ⁸ may be bonded to each other to form a ring together with the carbon atoms to which they are bonded, and the ring may have a substituent.
However, at least one of R ¹ and R ² is a halogen atom, an alkyl group, or a group represented by formula (3):

It is a group represented by the following formula:
A represents ═CH— or ═N—, and when A is ═CH—, it may have a substituent, and when A is ═N—, two or more A are ═N—. A plurality of A may be the same or different.
^R9 and ^R10 each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, a cyano group, or a dendron, and these groups may have a substituent.] The method according to claim 1, wherein at least one of R ⁵ to R ⁸ is a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, a cyano group, or a dendron. The method according to claim 1 or 2, wherein two adjacent groups among R ⁵ to R ⁸ are bonded to each other to form a ring together with the carbon atoms to which they are bonded, and the ring may have a substituent. The method according to any one of claims 1 to 3, wherein one of R ¹ and R ² is a halogen atom, an alkyl group, or a group represented by formula (3). The method according to any one of claims 1 to 4, wherein R ² is a halogen atom, an alkyl group, or a group represented by formula (3). The method according to any one of claims 1 to 5, wherein R ² is a group represented by formula (3). The method according to any one of claims 1 to 6, wherein all of A are =N- or all are =CH-, and the =CH- may have a substituent. The method according to any one of claims 1 to 7, wherein the alkoxy alcohol is an alkoxy alcohol having 3 to 12 carbon atoms. The method according to any one of claims 1 to 8, wherein the internal temperature of the reaction vessel during the reaction is 115°C or higher. A method for producing a compound represented by formula (5), comprising reacting iridium chloride with a compound represented by formula (2) in an alkoxy alcohol without adding water, and reacting the resulting compound represented by formula (1) with formula (4).

[In formula (1) and formula (2),
R ¹ to R ⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, a cyano group, or a dendron, and these groups may have a substituent. Two adjacent groups among ^{R 3} to R ⁸ may be bonded to each other to form a ring together with the carbon atoms to which they are bonded, and the ring may have a substituent.
However, at least one of R ¹ and R ² is a halogen atom, an alkyl group, or a group represented by formula (3):

It is a group represented by the following formula:
A represents ═CH— or ═N—, and when A is ═CH—, it may have a substituent, and when A is ═N—, two or more A are ═N—. A plurality of A may be the same or different.
^R9 and ^R10 each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, a cyano group, or a dendron, and these groups may have a substituent.]

[In formula (4),
R ¹¹ to R ¹⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine group, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, a cyano group, or a dendron, and these groups may have a substituent. Two adjacent groups among ^{R 11} to R ¹⁸ may be bonded to each other to form a ring together with the carbon atoms to which they are bonded.]

[In formula (5), R ¹ to R ⁸ and R ¹¹ to R ¹⁸ are the same as above.]