JP6344003B2 - Method for producing iridium complex compound, and iridium complex compound obtained by the method - Google Patents

Description

  The present invention relates to a method for producing an iridium complex compound and an iridium complex compound obtained by the production method. More specifically, the present invention relates to a method for producing an iridium binuclear complex compound and an iridium binuclear complex compound obtained by the production method.

In recent years, various electronic devices using organic electroluminescent elements (hereinafter also referred to as “organic EL elements”) such as organic EL lighting and organic EL displays are being put into practical use. An organic EL element has a low applied voltage, low power consumption, surface light emission, and can emit three primary colors. Therefore, application to lighting and displays has been actively studied.
It has been found that there is a high correlation between the emission quantum yield of an iridium complex compound and the emission efficiency of an organic EL device produced using the compound. Therefore, in order to obtain an organic EL element with high light emission efficiency, it is necessary to develop an iridium complex compound having a high light emission quantum yield.

  For example, as disclosed in Patent Document 1 and Non-Patent Documents 1 to 3, an iridium complex compound composed of iridium and an organic ligand is very stable as a complex and has various interesting chemical / photochemistry. It has attracted much attention in the fields of synthetic organic chemistry and optoelectronic devices. Among these, as for the iridium binuclear complex compound, many compounds are synthesized as synthetic intermediates of various iridium complex compounds, and are derived into various complex compounds according to the purpose.

International Publication No. 2009/073246

Inorganic Chemistry, 1993, 32, 3081-3087. Chemical Society Reviews, 2012, 41, 7061-7084. Highly Efficient OLEDs with Phosphorescent Materials, H. Yersin, WILEY-VCH, 2008.

However, little attention has been paid to the method for producing the iridium binuclear complex compound, and the iridium binuclear complex compound is produced using a known technique. In the process of synthesizing a desired iridium complex compound, the present inventors synthesized an iridium binuclear complex compound using a known technique. In the known technique, (1) conversion rate to an iridium binuclear complex compound It takes time to increase, (2) the purity of the resulting iridium binuclear complex compound is decreased, and (3) the synthesis yield of the iridium complex compound derived from the compound is decreased. It became clear.
Therefore, in the present invention, it is an object to shorten the reaction time when synthesizing the iridium binuclear complex compound, improve the purity, and improve the synthesis yield when using the compound.

As a result of intensive studies in view of the above problems, the present inventors have conducted distillation in a method for producing a specific iridium complex compound, preferably by removing a part of the solvent from the reaction system by distillation. As a result, it was found that the reaction time of the iridium binuclear complex compound can be shortened and the purity can be improved, and the present invention has been completed.
That is, the gist of the present invention is to react an iridium halide with a ligand represented by the following formula (2) in the presence of water and an organic solvent to produce an iridium complex compound represented by the following formula (1). A method for producing an iridium complex compound comprising a distillation step when reacting iridium halide with a ligand represented by the following formula (2) in the presence of water and an organic solvent: Lies in the way.

[In the formulas (1) and (2), Ir represents an iridium atom, and D represents a halogen atom. Ring A represents a 6-membered or 5-membered aromatic hydrocarbon ring or aromatic heterocyclic ring containing carbon atoms C ¹ and C ² , and Ring B contains carbon atom C ³ and nitrogen atom N ¹ Represents a 6-membered or 5-membered aromatic heterocycle.
The hydrogen atoms on ring A and ring B are each independently a fluorine atom, chlorine atom, bromine atom, alkyl group having 1 to 20 carbon atoms, (hetero) aralkyl group having 7 to 40 carbon atoms, or 1 to carbon atoms. 20 alkoxy groups, (hetero) aryloxy groups having 3 to 20 carbon atoms, alkylsilyl groups having 1 to 20 carbon atoms in the alkyl group, arylsilyl groups having 6 to 20 carbon atoms in the aryl group, carbon numbers An alkylcarbonyl group having 2 to 20 carbon atoms, an arylcarbonyl group having 7 to 20 carbon atoms, an alkylamino group having 2 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, or a (hetero) aryl group having 3 to 20 carbon atoms May be substituted. Further, adjacent substituents bonded to ring A and ring B may be bonded to form a ring. ]

  The production method of the present invention provides an efficient method for synthesizing an iridium binuclear complex compound, and improves the synthesis yield of an iridium complex compound derived from the iridium binuclear complex compound. It is.

(A) Temporal change of oil bath temperature and internal temperature when using the production method of the present invention, (b) The amount of solvent extracted from the reaction system by distillation when using the production method of the present invention, ( c) Conversion calculated by 1H-NMR. ¹ H-NMR spectrum of compound 1 (including unreacted ligand 1) (in a mixed solvent of DMSO-d ₆ and CDCl ₃ ).

  Embodiments of the present invention will be described in detail below. However, the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention.

<Method for producing iridium complex compound>
The method for producing an iridium complex compound represented by the formula (1) of the present invention comprises reacting iridium halide with a ligand represented by the formula (2) in the presence of water and an organic solvent, In the method for producing the iridium complex compound represented by the formula (1), when the iridium halide and the ligand represented by the formula (2) are reacted in the presence of water and an organic solvent, a distillation step It is characterized by having. More preferably, in the presence of water and an organic solvent having a boiling point of 120 ° C. or higher, iridium halide is reacted with a ligand represented by the formula (2), and the formula (1) In the step of synthesizing the represented iridium complex compound, when water and the organic solvent are removed from the reaction system by distillation, the internal temperature is increased by at least 10 ° C. or more. When the internal temperature in the reaction system during the distillation is increased by at least 10 ° C. from the internal temperature before the start of distillation, the reaction between the iridium halide and the ligand is promoted, and water and the organic solvent are The problem of the present invention can be solved by increasing the concentration of the unreacted compound and promoting the accompanying reaction by removing it from the reaction system.

<Internal temperature>
In the present invention, the internal temperature refers to the temperature of the solution in the reaction system, and the temperature of a heat medium such as an oil bath refers to the external temperature. Specifically, the internal temperature can be measured by inserting a thermometer, thermocouple, etc. into the reaction solution, but at this time it is also possible not to directly touch the reaction solvent using a sheath tube. preferable.

In the present invention, the internal temperature in the reaction system during distillation is preferably increased by at least 10 ° C. higher than the internal temperature before the start of distillation, but it is increased by 15 ° C. or more in order to increase the reaction rate. Is preferable, and it is more preferable to raise the temperature by 20 ° C or more. Moreover, it is preferable that the internal temperature before the start of distillation is equal to or higher than the boiling point of the organic compound contained in the organic solvent.
That is, the internal temperature in the reaction system during distillation is preferably an internal temperature that is at least 10 ° C. higher than the boiling point of the organic solvent, more preferably 15 ° C. or higher, and even more preferably 20 ° C. or higher. About the measuring method of internal temperature, and the method of removing a solvent out of a reaction system by distillation, it can measure using a known method.

<Distillation>
The distillation is not particularly limited. For example, “Fifth Edition Experimental Chemistry Course: Fundamentals I”
This can be done using the well-known technology published in “Basics of Experiments and Information”. Specifically, an experimental device combining a Dimroth cooling pipe with a branch pipe, a Liebig cooling pipe, etc. is assembled, and the reaction liquid is oiled. This can be done by heating to a temperature higher than the internal temperature before the start of distillation using a heat medium such as a bath. Preferably, the internal temperature in the reaction system during distillation is preferably at least 10 ° C. higher than the internal temperature before the start of distillation, but as a means for increasing the internal temperature by 10 ° C. or higher, heating is performed at the external temperature. However, from the viewpoint of distillation efficiency and the like, it is more preferable to heat at an external temperature that is 20 ° C. or higher, and it is more preferable that the temperature is higher by 30 ° C. About the timing which begins to remove a solvent out of a reaction system by distillation, if it is after reflux begins, it is arbitrary. At this time, it may be carried out at normal pressure or under reduced pressure, but it is more preferred to carry out at normal pressure in order to increase the temperature of the reaction solution.
The amount of the solvent partially removed by distillation is not a problem as long as at least a part of the solvent is removed by distillation. Specifically, 5% or more of the total amount of solvent at the time of charging is preferable, and 10% or more is preferable. More preferably, 80% or less is preferable, and 60% or less is more preferable.

<Solvent>
The solvent that can be used in the production method of the present invention is not particularly limited as long as it contains at least water and an organic solvent, but preferably contains an organic compound having a boiling point of 120 ° C. or higher in the organic solvent. It is preferable that the organic solvent is an organic compound having a temperature of 120 ° C. or higher. Specifically, N, N-dimethylformamide, N, N-dimethylacetamide, ethylene glycol, diethylene glycol, triethylene glycol, ethylene glycol derivatives (ethylene glycol monoalkyl ethers, ethylene glycol monoaryl ethers, ethylene glycol dialkyl ethers) Among them, ethylene glycol and ethylene glycol derivatives are preferable, ethylene glycol derivatives are more preferable, ethylene glycol derivatives are more preferable, and ethylene glycol derivatives are more preferable. Glycol monoalkyl ethers are particularly preferred.

  Here, as ethylene glycol monoalkyl ethers, 2-methoxyethanol, 2-ethoxyethanol, 2-propylethanol, 2-isopropylethanol, 2-normalbutylethanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol Examples thereof include monoethyl ether, among which 2-methoxyethanol and 2-ethoxyethanol are preferable. Examples of ethylene glycol monoaryl ethers include 2-phenoxyethanol. Examples of the ethylene glycol dialkyl ethers include 1,2-diethoxyethane, diglyme, triglyme, diethylene glycol diethyl ether, and the like, among which 1,2-diethoxyethane and diglyme are more preferable.

  Regarding the mixing ratio of water and the organic solvent, the volume ratio of water to the total amount of the solvent is not particularly limited in consideration of the low solubility of the ligand in water, but is preferably 50% or less. 30% or less, more preferably 20% or less, considering the low solubility of iridium halide in an organic solvent, preferably 1% or more, and more preferably 5% or more. More preferably.

<Iridium halide>
As the iridium halide, iridium chloride, iridium bromide, salts of these compounds (for example, sodium chloroiridate, potassium chloroiridate), and hydrates of the aforementioned compounds can be used. The iridium halide may be synthesized and used in the system by treating a compound such as Ir (acac) ₃ complex or Ir cyclooctadienyl complex with hydrochloric acid or the like.

<Ligand>
The ligand represented by the following formula (2) used in the production method of the present invention will be described.

In the above formula (2), ring A is a 6-membered or 5-membered ring containing carbon atoms C ¹ and C ² .
An aromatic hydrocarbon ring or an aromatic heterocyclic ring is represented, and ring B represents a 6-membered or 5-membered aromatic heterocyclic ring containing carbon atom C ³ and nitrogen atom N ¹ . Examples of the 6-membered ring or 5-membered aromatic hydrocarbon ring or aromatic heterocycle include a benzene ring, a pyridine ring, a furan ring, a thiophene ring, a pyrrole ring, etc., among which a benzene ring and a pyridine ring are preferable. More preferred is a benzene ring. Examples of the 6-membered or 5-membered aromatic heterocycle include a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazine ring, an imidazole ring, an oxazole ring, a thiazole ring, and the like. Among them, a pyridine ring, a pyrazine ring, a pyrimidine ring, An imidazole ring, an oxazole ring and a thiazole ring are preferable, and a pyridine ring, an oxazole ring and a thiazole ring are more preferable.

  The hydrogen atoms on ring A and ring B are each independently a fluorine atom, chlorine atom, bromine atom, alkyl group having 1 to 20 carbon atoms, (hetero) aralkyl group having 7 to 40 carbon atoms, or 1 to carbon atoms. 20 alkoxy groups, (hetero) aryloxy groups having 3 to 20 carbon atoms, alkylsilyl groups having 1 to 20 carbon atoms in the alkyl group, arylsilyl groups having 6 to 20 carbon atoms in the aryl group, carbon numbers An alkylcarbonyl group having 2 to 20 carbon atoms, an arylcarbonyl group having 7 to 20 carbon atoms, an alkylamino group having 2 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, or a (hetero) aryl group having 3 to 20 carbon atoms May be substituted. When a hydrogen atom is substituted, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, or a (hetero) aryl group having 3 to 20 carbon atoms is preferable from the viewpoint of durability. In particular, an aryl group having 3 to 20 carbon atoms is more preferable.

  Further, adjacent substituents bonded to ring A and ring B may be bonded to form a ring. Specific examples of such rings include fluorene ring, naphthalene ring, phenanthrene ring, triphenylene ring, chrysene ring, benzofuran ring, dibenzofuran ring, benzothiophene ring, dibenzothiophene ring, carbazole ring, carboline ring, diazacarbazole ring, Examples thereof include a tetrahydronaphthalene ring, a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, an azaphenanthrene ring, an azatriphenylene ring, a benzimidazole ring, a benzoxazole ring, and a benzthiazole ring. Among these, a fluorene ring, naphthalene ring, carbazole ring, carboline ring, quinoline ring, quinazoline ring, quinoxaline ring, azatriphenylene ring, benzoxazole ring, and benzthiazole ring are preferable.

  Specific examples of the alkyl group having 1 to 20 carbon atoms include a linear alkyl group, a branched alkyl group, and a cyclic alkyl group, and more specifically, a methyl group, an ethyl group, a propyl group, and an isopropyl group. , N-butyl group, n-pentyl group, n-hexyl group, n-octyl group, isopentyl group, cyclohexyl group and the like. Among these, straight chain alkyl groups such as a methyl group, an ethyl group, an n-pentyl group, an n-hexyl group, and an n-octyl group are preferable.

  As specific examples of the (hetero) aralkyl group having 7 to 40 carbon atoms, a part of hydrogen atoms constituting a linear alkyl group, a branched alkyl group, and a cyclic alkyl group are substituted with a (hetero) aryl group. More specifically, 1-phenyl-1-ethyl group, cumyl group, 5-phenyl-1-pentyl group, 6-phenyl-1-hexyl group, 7-phenyl-1-heptyl group And tetrahydronaphthyl group. Of these, a 5-phenyl-1-pentyl group, a 6-phenyl-1-hexyl group, and a 7-phenyl-1-heptyl group are preferable.

Specific examples of the alkoxy group having 1 to 20 carbon atoms include methoxy group, ethoxy group, hexyloxy group, cyclohexyloxy group, octadecyloxy group and the like. Of these, a methoxy group and a hexyloxy group are preferable.
Specific examples of the (hetero) aryloxy group having 3 to 20 carbon atoms include a phenoxy group and a 4-methylphenyloxy group. Of these, a phenoxy group is preferable.

  Specific examples of the alkylsilyl group having 1 to 20 carbon atoms in the alkyl group include trimethylsilyl group, triethylsilyl group, triisopropylsilyl group, dimethylphenyl group, t-butyldimethylsilyl group, t-butyldiphenylsilyl group and the like. Among them, triisopropylsilyl group, t-butyldimethylsilyl group, and t-butyldiphenylsilyl group are preferable.

Specific examples of the arylsilyl group having 6 to 20 carbon atoms in the aryl group include a diphenylmethylsilyl group and a triphenylsilyl group. Among them, a triphenylsilyl group is preferable.
Specific examples of the alkylcarbonyl group having 2 to 20 carbon atoms include an acetyl group, a propionyl group, a pivaloyl group, a caproyl group, a decanoyl group, and a cyclohexylcarbonyl group, and among them, an acetyl group and a pivaloyl group are preferable.

Specific examples of the arylcarbonyl group having 7 to 20 carbon atoms include a benzoyl group, a naphthoyl group, and an anthryl group, and among them, a benzoyl group is preferable.
Specific examples of the alkylamino group having 2 to 20 carbon atoms include a methylamino group, a dimethylamino group, a diethylamino group, an ethylmethylamino group, a dihexylamino group, a dioctylamino group, and a dicyclohexylamino group. Group, dicyclohexylamino group is preferred.

Specific examples of the arylamino group having 6 to 20 carbon atoms include phenylamino group, diphenylamino group, di (4-tolyl) amino group, di (2,6-dimethylphenyl) amino group and the like. An amino group and a di (4-tolyl) amino group are preferred.
A (hetero) aryl group having 3 to 20 carbon atoms means both an aromatic hydrocarbon group and an aromatic heterocyclic group having one free valence.

  Specific examples include a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, fluoranthene ring, furan ring, having one free valence, Benzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole Ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, tri Jin ring, a quinoline ring, an isoquinoline ring, cinnoline ring, quinoxaline ring, benzimidazole ring, perimidine ring, a quinazoline ring, a quinazolinone ring, and a group of azulene ring.

From the viewpoint of durability, a benzene ring, a naphthalene ring, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, a pyridine ring, a pyrimidine ring, and a triazine ring having one free valence are preferable, and among them, one free valence is preferable. More preferred are benzene rings and pyridine rings having
Here, in the present invention, free valence can form bonds with other free valences as described in Organic Chemistry / Biochemical Nomenclature (above) (Revised 2nd edition, Nankodo, 1992). Say things. That is, for example, “a benzene ring having one free valence” refers to a phenyl group, and “a benzene ring having two free valences” refers to a phenylene group.

When the ligand represented by the formula (2) includes an alkyl group having 5 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, or a substituent represented by the formula (3). The production method of the present invention can provide more remarkable effects. Although the detailed mechanism that exerts a remarkable effect has not been clarified, since the ligand having these substituents is highly soluble in organic solvents, side reactions are likely to proceed by heating for a long time. It is presumed that, by applying the production method of the present invention, unnecessary heating can be avoided, so that the amount of by-products is reduced and the effects of the present invention are exhibited.

Specific examples of the alkyl group having 5 to 20 carbon atoms include a linear alkyl group, a branched alkyl group, and a cyclic alkyl group, and more specifically, n-pentyl group, n-hexyl group, n -An octyl group, an isopentyl group, a cyclohexyl group, etc. are mentioned. Of these, linear alkyl groups such as an n-pentyl group, an n-hexyl group, and an n-octyl group are preferable. As specific examples of the (hetero) aralkyl group having 7 to 40 carbon atoms, a part of hydrogen atoms constituting a linear alkyl group, a branched alkyl group, and a cyclic alkyl group are substituted with a (hetero) aryl group. More specifically, 1-phenyl-1-ethyl group, cumyl group, 5-phenyl-1-pentyl group, 6-phenyl-1-hexyl group, 7-phenyl-1-heptyl group And tetrahydronaphthyl group. Of these, a 5-phenyl-1-pentyl group, a 6-phenyl-1-hexyl group, and a 7-phenyl-1-heptyl group are preferable.
Hereinafter, the substituent represented by the following formula (3) will be described.

In the formula (3), R ^{11 to} R ¹⁴ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, or a (hetero) aralkyl having 7 to 40 carbon atoms. Represents a group, an alkoxy group having 1 to 20 carbon atoms, a (hetero) aryloxy group having 3 to 20 carbon atoms, or a (hetero) aryl group having 3 to 20 carbon atoms. R ^{15 to} R ¹⁹ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, or 1 to 20 carbon atoms. An alkoxy group, or a (hetero) aryloxy group having 3 to 20 carbon atoms. p represents an integer of 1 to 3, and a plurality of R ^{11 to} R ¹⁴ may be the same or different from each other. C1-C20 alkyl group, C7-C40 (hetero) aralkyl group, C1-C20 alkoxy group, C3-C20 (hetero) aryloxy group, or C3-C20 Specific examples of the (hetero) aryl group are the same as those described above.

  As a method for synthesizing the ligand represented by the formula (2), a known synthesis method can be used. For example, it is disclosed in ACS Applied Materials & Interfaces, 2013, Vol. 5, No. 11, pages 4937-4944, International Publication No. 2009/073246, International Publication No. 2013/072740, International Publication No. 2013/105615. It can be synthesized by combining the methods.

  The production method of the present invention is effective when the ligand represented by the formula (2) is used, but is more prominent when the ligand represented by the following formula (2-1) is used. Effects can be obtained. Hereinafter, the following formula (2-1) will be described.

In the formula (2-1), R ^{1 to} R ⁸ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, or a heteroalkyl having 7 to 40 carbon atoms (hetero ) Represents an aralkyl group, an alkoxy group having 1 to 20 carbon atoms, a (hetero) aryloxy group having 3 to 20 carbon atoms, or a (hetero) aryl group having 3 to 20 carbon atoms. These groups are further substituted. You may have. Specific examples of these substituents are as described above.

Moreover, adjacent R < ¹ > -R < ⁸ > may couple | bond together and may form a ring further, and the formed ring may have a substituent further. Specific examples of such rings include fluorene ring, naphthalene ring, phenanthrene ring, triphenylene ring, chrysene ring, dibenzofuran ring, carbazole ring, carboline ring, diazacarbazole ring, tetrahydronaphthalene ring, quinoline ring, isoquinoline ring, quinazoline Ring, quinoxaline ring, azaphenanthrene ring, azatriphenylene ring and the like. Among these, a fluorene ring, naphthalene ring, carbazole ring, carboline ring, quinoline ring, quinazoline ring, quinoxaline ring, azatriphenylene ring, benzoxazole ring, and benzthiazole ring are preferable.

<Iridium complex compound>
The iridium binuclear complex compound represented by the following formula (1) obtained by the production method of the present invention will be described.

  In the formula (1), Ir represents an iridium atom, and D represents a halogen atom. The halogen atom is preferably a chlorine atom or a bromine atom from the viewpoint of raw material procurement, but may be an iodine atom. Ring A and ring B are the same as those described in the section of formula (2).

The ratio of the substrate used when synthesizing the iridium binuclear complex compound represented by the formula (1) is preferably 2 equivalents or more, and 2.1 equivalents or more, based on iridium halide. Is more preferable, and it is preferably used at 3 equivalents or less, more preferably at 2.8 equivalents or less. When used at a ratio of less than 2 equivalents, both the conversion and yield are reduced because the stoichiometric ratio is not reached, and when used at a ratio of greater than 3 equivalents, the unreacted ligand is iridium dioxygen. Since it is mixed with the nuclear complex compound, the purity is extremely reduced.

The concentration of the substrate used when synthesizing the iridium binuclear complex compound represented by the formula (1) is arbitrary, but if the concentration is too low, the reaction rate becomes low, and if the concentration is too high, the substrates are mixed well. Therefore, it is preferable to use the following concentrations in order to hinder the progress of the reaction. That is, the molar concentration of iridium halide at the time of reaction preparation is preferably 1 mmol / L or more, more preferably 5 mmol / L or more, preferably 2 mol / L or less, and more preferably 1 mol / L or less.
The reaction time for synthesizing the iridium binuclear complex compound represented by the formula (1) is usually 30 minutes to 72 hours, preferably 1 hour to 48 hours, and more preferably 2 hours to 24 hours. It is also preferable to carry out the reaction in a nitrogen atmosphere or an argon atmosphere.

<Reason why the production method of the present invention is effective>
Although the details of the mechanism by which the effects of the present invention can be obtained by the manufacturing method of the present invention have not been clarified at present, it is presumed as follows. As described above, the compound represented by the formula (1) is synthesized by reacting iridium halide with the compound represented by the formula (2). In general, iridium halides have low solubility in organic solvents, while organic ligands have low solubility in water. Therefore, when synthesizing iridium binuclear complex compounds, a solvent system in which water and an organic solvent are mixed is used. Is used. However, in these solvent systems, even if heating is performed in an oil bath or the like having a boiling point higher than that of the organic solvent, the internal temperature stops at around 100 ° C., which is the boiling point of water. For this reason, it takes a long time until the reaction between the iridium halide and the ligand is completed, and many undesirable by-products are generated due to the long reaction time. The present invention provides a production method for improving these problems, and it is presumed that a desired effect can be obtained by using the production method of the present invention.

<Specific example>
Specific preferred examples of the iridium complex compound of the present invention are shown below, but the present invention is not limited thereto. In the present specification, Me represents a methyl group.

<Uses of iridium complex compounds>
The iridium complex compound synthesized by the production method of the present invention exhibits interesting chemical / photochemical characteristics, and is useful as an intermediate for the synthesis of various iridium complex compounds. It can be used in the area.
The iridium complex compound synthesized by the production method of the present invention can also use an organic electroluminescent element, and can be applied to an organic electroluminescent device using this element, specifically, a display device or a lighting device. There is no restriction | limiting in particular about this form and structure, It can assemble in accordance with a conventional method using the iridium complex compound of this invention.

  For example, the display device and the illumination device of the present invention can be obtained by the method described in “Organic EL display” (Ohm, published on August 20, 2004, Shizutoki Toki, Chiba Adachi, Hideyuki Murata). Can be formed.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. The values of various conditions and evaluation results in the following examples have meanings as preferred values of the upper limit or lower limit in the embodiments of the present invention, and the preferred ranges are the above upper limit or lower limit values and the following values: It may be a range defined by a combination of values of the examples or values between the examples.
<Synthesis Example of Ligand 1>
(Synthesis example of intermediate 1)

Under a nitrogen atmosphere, 5-chloro-2-nitrobenzaldehyde (50.8 g), iron powder (38.8 g), ethanol (440 mL), and 0.2N hydrochloric acid (60 mL) were sequentially added, and the mixture was stirred at 95 ° C. for 3 hours. . After returning to room temperature, potassium hydroxide (19.6 g) and 3′-bromoacetophenone (51.2 g) were sequentially added, and the mixture was further stirred for 2 hours. Water (50 mL) and methylene chloride (500 mL) were added, followed by celite filtration. The filtrate was dried over MgSO4 and concentrated. The product was purified by silica gel column chromatography and reprecipitated from methylene chloride / methanol to obtain synthetic intermediate 1 (66.2 g, yield 76%). 5-Chloro-2-nitrobenzaldehyde was purchased from Tokyo Chemical Industry Co., Ltd., and 3′-bromoacetophenone was purchased from Sigma-Aldrich.
(Synthesis example of ligand 1)

Under a nitrogen atmosphere, Intermediate 1 (56.0 g), 4-hexylphenylboronic acid (62.9 g), toluene (225 mL), ethanol (115 mL), Pd (PPh ₃ ) ₄ (4.06 g), distilled water ( 120 mL) and sodium carbonate (25.2 g) were added in this order, and the mixture was stirred for 3 hours while being heated to reflux. After returning to room temperature, distilled water and methylene chloride were added, and the organic phase was separated. The organic phase was washed with water and a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography, and the obtained solid was directly used in the next reaction. Under a nitrogen atmosphere, the obtained solid, 4-hexylphenylboronic acid (54.6 g), palladium acetate (1.19 g), S-PHOS (4.37 g), tripotassium phosphate (114 g), dehydrated toluene (300 mL) ) In this order, followed by stirring for 30 hours while heating to reflux at 120 ° C. While confirming the progress of the reaction, a palladium catalyst, SPHOS, and boronic acid were appropriately added. After returning to room temperature, insoluble matters were removed by suction filtration, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain ligand 1 (63.8 g, yield 69%). In addition, S-PHOS is a common name of the compound of CAS number 657408-07-6, and the thing by Wako Pure Chemical Industries Ltd. was used. 4-hexylphenylboronic acid was purchased from SYNTHON Chemicals.

The measurement result of ¹ H-NMR of the obtained compound is shown below.
¹ H-NMR (CDCl ₃ , ppm); 8.40 (t, 1H), 8.27-8.22 (m, 2H), 8.14-8.11 (m, 1H), 8.01- 7.98 (m, 2H), 7.94 (d, 1H), 7.70-7.56 (m, 6H), 7.30 (t, 4H), 2.70-2.65 (m, 4H), 1.71-1.63 (m, 4H), 1.42-1.31 (m, 12H), 0.92-0.89 (s, 6H).

  <Example 1: Synthesis example of iridium binuclear complex 1>

Under a nitrogen atmosphere, ligand 1 (30.0 g), distilled water (40 mL), 2-ethoxyethanol (400 mL, boiling point 135 ° C.) were sequentially added, and the mixture was stirred in a 120 ° C. oil bath. Five minutes after the internal temperature reached 100 ° C., iridium chloride hydrate (8.96 g) was added and further stirred. After 1 hour, an operation for removing the solvent out of the reaction system by distillation was started. After 3 hours and 6 hours, the temperature of the oil bath was increased to 150 ° C. and 160 ° C., respectively, and the mixture was heated and stirred for 20 hours while removing the solvent. The total amount of solvent removed by the end of the reaction was about 170 mL, and the internal temperature at the end of the reaction was 128 ° C. After cooling to room temperature, dichloromethane (600 mL) and distilled water (300 mL) were added, and the organic phase was separated. The organic phase was washed with water, dried over sodium sulfate, and the solvent was distilled off under reduced pressure. The residue was reprecipitated with dichloromethane / methanol to obtain Compound 1 (33.8 g, ¹ H-NMR yield 88%). The NMR yield was determined by calculating the ratio from the integral ratio of the benzylic hydrogen of ligand 1 and compound 1. The peak of benzylic hydrogen appears in the vicinity of 2.7 ppm to 2.5 ppm, and the triple line peak on the low magnetic field side shows benzylic hydrogen (4H) of the unreacted ligand and benzylic hydrogen (4H) of the target product. ), The triple line peak on the high magnetic field side is attributed to the target benzylic hydrogen (4H). Also, the internal temperature / oil bath temperature during the reaction, the amount of solvent removed, the conversion rate to compound 1 (determined by ¹ H-NMR), and the ¹ H-NMR spectrum of compound 1 (including unreacted ligand 1) Are shown in FIGS.

<Comparative Example 1>
The reaction was conducted in the same manner as in Example 1 except that the operation for removing the solvent out of the reaction system by distillation was not performed in Example 1. As a result, the ¹ H-NMR yield of Compound 1 was 51%.

Claims (5)

In the method of producing an iridium complex compound represented by the following formula (1) by reacting iridium chloride with a ligand represented by the following formula (2-1) in the presence of water and an organic solvent, A method for producing an iridium complex compound, comprising a distillation step when iridium chloride is reacted with a ligand represented by the following formula (2-1) in the presence of an organic solvent.

[In the formulas (1) and (2-1), Ir represents an iridium atom,
R ^{1 to} R ⁸ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, or 1 to 20 carbon atoms. Represents an alkoxy group, a C 3-20 (hetero) aryloxy group, or a C 3-20 (hetero) aryl group, these groups may further have a substituent.
Moreover, adjacent R < ¹ > -R < ⁸ > may couple | bond together and it may form a ring further, and the formed ring may have a substituent further.   The method for producing an iridium complex compound according to claim 1, wherein the organic solvent is an organic compound having a boiling point of 120 ° C or higher.   The method for producing an iridium complex compound according to claim 1 or 2, wherein the internal temperature in the reaction system during distillation is higher by 10 ° C or higher than the internal temperature before the start of distillation.   The method for producing an iridium complex compound according to any one of claims 1 to 3, wherein ethylene glycol or an ethylene glycol derivative is used as the organic solvent. Formula (2-1) is an alkyl group having 5 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 4 to 20 carbon atoms, and a (hetero) aryloxy having 3 to 20 carbon atoms. The manufacturing method of the iridium complex compound as described in any one of Claims 1-4 containing the substituent represented by group or following formula (3).
[Wherein, R ^{11 to} R ¹⁴ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, carbon A C1-C20 alkoxy group, a C3-C20 (hetero) aryloxy group, or a C3-C20 (hetero) aryl group is represented. R ^{15 to} R ¹⁹ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, or 1 to 20 carbon atoms. An alkoxy group, or a (hetero) aryloxy group having 3 to 20 carbon atoms. p represents an integer of 1 to 3, and a plurality of R ^{11 to} R ¹⁴ may be the same or different. ]