JP2020083767A - Cyclometallized iridium complex manufacturing method and iridium acetate used suitably for manufacturing method - Google Patents

Abstract

To provide a method of manufacturing a cyclometallized iridium complex useful as a phosphorescent material for, e.g., an organic electroluminescent element.SOLUTION: A method of manufacturing a cyclometallized iridium complex comprises reacting iridium acetate with a heteroaromatic ring bidentate ligand represented by general formula (1). (In the formula, CyA is a N-containing 5- or 6-membered cyclic group, and CyB is a C-containing 5- or 6-membered cyclic group, provided that CyA and CyB may bind to each other to form a ring structure.)SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a method for producing a cyclometalated iridium complex which is useful as a light emitting material for an organic electroluminescence device, and iridium acetate which is preferably used in the production method.

Organic electroluminescent devices have attracted attention as a next-generation display technology, and research and development for practical use have been actively promoted. It has been widely known so far that the use of a phosphorescent material in the light emitting layer of an organic electroluminescent device improves the light emitting efficiency. As a typical phosphorescent material, there is a cyclometalated iridium complex having an aromatic heterocyclic bidentate ligand (for example, tris(2-phenylpyridine)iridium shown in Chemical formula 3).

As a method for producing such a cyclometalated iridium complex, a method is known in which iridium acetate is reacted with an aromatic heterocyclic bidentate ligand (see, for example, Patent Document 1). In addition, a method is known in which Ir(acac) ₃ (acac=acetylacetonate) is reacted with an aromatic heterocyclic bidentate ligand (see, for example, Patent Document 2).

JP 2012-6914 A Japanese Patent Publication No. 2004-526700 Japanese Patent Publication No. 2008-542223 European Patent Application Publication No. 01046629 International Publication No. 96/023757

The method for producing a cyclometalated iridium complex using iridium acetate described in Patent Document 1 has a higher yield of the cyclometalated iridium complex at a reaction temperature as low as 50 to 100° C. than the method described in Patent Document 2. There are features that can be obtained.

It is disclosed in Patent Document 1 that the structure of iridium acetate (manufactured by ChemPur GmbH) actually used is Ir(CH ₃ COO) ₃ and its molecular weight is 369.35. However, in general, the definition of iridium acetate is very broad, and its structure is not clear. For example, as disclosed in Japanese Patent Publication No. 2008-542223 (Patent Document 3), it is known that iridium acetate refers to all compounds having an iridium atom and an acetate salt. Therefore, what kind of iridium acetate should be specifically used in order to produce a cyclometalated iridium complex with a high yield, that is, a mononuclear complex (Irdium having three acetate ligands coordinated to iridium). It has not been fully clarified whether it should be (CH ₃ COO) ₃ ).

Further, according to the knowledge of the present inventors, there is a problem that the yield and the purity of the cyclometalated iridium complex are lowered depending on the iridium acetate used.

An object of the present disclosure is to provide a method for producing a cyclometalated iridium complex that is useful as a phosphorescent material for an organic electroluminescent device, and iridium acetate that is preferably used in the production method.

The inventors of the present invention have conducted extensive studies in view of the above circumstances, and as a result of mass spectrometric analysis of iridium acetate, it has been found that iridium acetate contains a plurality of components. Among them, in particular, it was found that an iridium compound showing a peak at a mass-to-charge ratio (m/z)=947±1 detected by mass spectrometry is suitable as a raw material for a cyclometalated iridium complex, and the present invention is completed. I arrived.

That is, according to this application, the following inventions are provided.

The method for producing a cyclometalated iridium complex according to the present invention is a method for producing a cyclometalated iridium complex by reacting iridium acetate with an aromatic heterocyclic bidentate ligand represented by the general formula (1). As the iridium acetate, use an iridium compound that shows a peak at the mass-to-charge ratio (m/z)=947±1 when the applied voltage for introducing ions into the mass analysis section by mass spectrometry is 30 to 50V. Is characterized by.
(In the general formula (1), N represents a nitrogen atom, C represents a carbon atom, H represents a hydrogen atom, CyA represents a 5-membered or 6-membered cyclic group containing a nitrogen atom, and CyB represents It represents a 5-membered or 6-membered cyclic group containing a carbon atom, and CyA and CyB may combine to form a ring structure.)

In the method for producing a cyclometalated iridium complex according to the present invention, when the peak intensity at m/z=947±1 is 100%, iridium acetate having a peak intensity at m/z=620±1 of less than 50% is used. It is preferable to use. It has been revealed that the presence of many components in iridium acetate having a peak at m/z=620 adversely affects the production of the cyclometalated iridium complex. Therefore, the inventors of the present invention use iridium acetate whose peak intensity at m/z=620±1 is less than 50% when the peak intensity at m/z=947±1 is set to 100%. It has been found that the cyclometalated iridium complex can be obtained in higher yield.

In the method for producing a cyclometalated iridium complex according to the present invention, the ionization method in mass spectrometry is preferably an electrospray ionization (ESI) method.

In the method for producing a cyclometalated iridium complex according to the present invention, the aromatic heterocyclic bidentate ligand is preferably any of the general formulas (2) to (6).
(In formulas (2) to (6), R ^{1 to} R ⁴⁸ each independently represent a hydrogen atom or a substituent.)

In the method for producing a cyclometalated iridium complex according to the present invention, the cyclometalated iridium complex is preferably a triscyclometalated iridium complex.

The iridium acetate according to the present invention is characterized by showing a peak at a mass-to-charge ratio (m/z)=947±1 when an applied voltage for introducing ions into a mass spectrometric section is 30 to 50 V by mass spectrometry. To do.

The iridium acetate according to the present invention preferably has a peak intensity at m/z=620±1 of less than 50% when the peak intensity at m/z=947±1 is 100%.

In the iridium acetate according to the present invention, the ionization method in mass spectrometry is preferably the electrospray ionization (ESI) method.

According to the present disclosure, it is possible to provide a method for producing a cyclometalated iridium complex that is useful as a light emitting material for an organic electroluminescent device, and iridium acetate that is preferably used in the method.

It is an example of a mass spectrum when a methanol solution of iridium acetate is analyzed by electrospray ionization mass spectrometry.

Next, the present invention will be described in detail by showing embodiments, but the present invention is not construed as being limited to these descriptions. The embodiments may be variously modified as long as the effects of the present invention are exhibited.

The production method of the present invention is a production method of a cyclometalated iridium complex that can be suitably used as a phosphorescent material such as an organic electroluminescence device, and an applied voltage for introducing ions into a mass spectrometry unit by mass spectrometry is When 30 to 50 V, iridium acetate showing a peak at a mass-to-charge ratio (m/z)=947±1 is reacted with an aromatic heterocyclic bidentate ligand represented by the general formula (1). And

Iridium acetate used in the production method of the present invention has a peak at a mass-to-charge ratio (m/z) of 947±1. The yield of the desired cyclometalated iridium complex can be increased as compared to iridium acetate which does not show a peak at the mass-to-charge ratio (m/z)=947±1.

The iridium acetate used in the production method of the present invention has a peak intensity of m/z=620±1 of less than 50% when the peak intensity of m/z=947±1 detected by a mass spectrometer is 100%. Is preferred. The yield of the desired cyclometalated iridium complex can be further increased as compared with the case where iridium acetate having a peak intensity of m/z=620±1 of 50% or more is used. Assuming that the peak intensity of m/z=947±1 detected by the mass spectrometer is 100%, the peak intensity of m/z=620±1 is more preferably less than 30%, and less than 15%. It is particularly preferable that it is less than 10%, and it is most preferable that it is less than 8%.

The peak intensity is preferably the peak height.

It is speculated that m/z=947 is a fragment peak corresponding to the molecular formula: C ₁₂ H ₁₈ Ir ₃ O ₁₃ . That is, the peak at m/z=947 is presumed to be a trinuclear complex.

It is speculated that m/z=620 is a fragment peak corresponding to the molecular formula: C ₈ H ₁₂ Ir ₂ O ₈ . That is, the peak at m/z=620 is estimated to be a binuclear complex.

The above-mentioned value of m/z is slightly different depending on the separation accuracy of the mass spectrometer, the type of the detector, etc., and thus is acceptable within the range of ±1.

The ionization method in the mass spectrometer is not particularly limited, and includes electron ionization (EI) method, chemical ionization (CI) method, desorption electron ionization (DEI) method, desorption chemical ionization (DCI) method, and fast atom collision. (FAB) method, electrospray ionization (ESI) method, atmospheric pressure chemical ionization (APCI) method, matrix-assisted laser desorption ionization (MALDI) method and the like. Among them, the electrospray ionization (ESI) method is preferable.

As a condition for mass spectrometry, the applied voltage for introducing ions generated at the interface of the mass spectrometer into the mass spectrometer (called as drift voltage, fragmentor voltage, extract voltage, cone voltage, etc. depending on the model of the spectrometer) ) Is 30 to 50V, more preferably 35 to 50V, particularly preferably 40 to 50V, and most preferably 45 to 50V. On the other hand, when the applied voltage for introducing ions into the mass spectrometric section in the mass spectrometry is less than 30 V, there are various peaks due to addition of solvent, water, etc. to the fragment showing m/z=947 and m/z=620. Are observed, and the peak becomes complicated, which is not preferable. If the applied voltage for introducing ions into the mass spectrometric section exceeds 50 V in mass spectrometry, the peak intensity may decrease. It is preferable to set the applied voltage to 30 to 50 V because a spectrum that is simple and easy to analyze can be obtained.

As conditions for mass spectrometry, the capillary voltage is preferably 1 to 5 kV, more preferably 2 to 5 kV, and particularly preferably 3 to 5 kV.

As conditions for mass spectrometry, the ion source temperature is preferably 100 to 700°C, more preferably 100 to 500°C, and particularly preferably 100 to 200°C.

As conditions for mass spectrometry, the desolvation temperature is preferably 100 to 500°C, preferably 100 to 300°C, and particularly preferably 150 to 250°C.

As conditions for mass spectrometry, the desolvation gas flow rate is preferably 100 to 800 L/Hr, preferably 100 to 300 L/Hr, and particularly preferably 100 to 200 L/Hr.

As conditions for mass spectrometry, the cone gas flow rate is preferably 10 to 200 L/Hr, preferably 10 to 100 L/Hr, and particularly preferably 20 to 80 L/Hr.

The positive mode is preferable as the condition for the mass spectrometry.

The mass spectrometer used in the present invention is preferably a time-of-flight mass spectrometer, a single collector magnetic field mass spectrometer, or a quadrupole mass spectrometer, and it is a quadrupole mass spectrometer. Is more preferable.

When iridium acetate used in the production method of the present invention is analyzed by a mass spectrometer, it is preferable to dissolve iridium acetate in a solvent in advance. The solvent is not particularly limited, but an alcohol solvent or a nitrile solvent is preferable, an alcohol solvent is more preferable, and methanol is particularly preferable. It is particularly preferable to dissolve iridium acetate in the above-mentioned solvent and then perform analysis with a mass spectrometer after a certain time has elapsed. The fixed time is preferably 1 to 48 hours, more preferably 5 to 24 hours, and particularly preferably 12 to 24 hours. Providing a certain period of time improves the detection sensitivity of iridium acetate in mass spectrometry, which is preferable.

FIG. 1 shows an example of a mass spectrum when an methanol solution of iridium acetate is analyzed by electrospray ionization mass spectrometry. From FIG. 1, a peak at m/z=947±1 (m/z=946.6 in FIG. 1) and a peak at m/z=620±1 (m/z=619.5 in FIG. 1) are observed. You can see that it is done. In the case of this iridium acetate, when the peak intensity at m/z=947±1 is 100%, the peak intensity at m/z=620±1 is calculated to be 27.7%. The applied voltage (cone voltage) for introducing ions into the mass spectrometric section by mass spectrometry is 50V.

Iridium acetate is a known production method (for example, Japanese Patent Publication No. 2008-542223 (Patent Document 3), European Patent Application Publication No. 01046629 (Patent Document 4), and International Publication No. 96/023757 (Patent Document 5)). , And can be easily manufactured with reference to these documents. Various kinds of iridium acetate can be produced by appropriately changing the reaction conditions (addition amount of acetic acid, reaction time, reaction temperature, substrate concentration, etc.).

Next, R ^{1 to} R ⁴⁸ , CyA and CyB described in the general formulas (1) to (6) will be described.

R ^{1 to} R ⁴⁸ are hydrogen atoms or substituents. As the substituent, for example, an alkyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, for example, methyl, ethyl, iso-propyl, tert-butyl). , N-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably carbon). The number is 2 to 10, and examples thereof include vinyl, allyl, 2-butenyl, 3-pentenyl, and the like, alkynyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably carbon). A number of 2 to 10, for example, propargyl, 3-pentynyl, etc.), an aryl group (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms). , For example, phenyl, p-methylphenyl, naphthyl, anthranyl, etc.), an amino group (preferably having 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, particularly preferably 0 to 10 carbon atoms, Examples thereof include amino, methylamino, dimethylamino, diethylamino, dibenzylamino, diphenylamino, ditolylamino, etc.), an alkoxy group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably carbon). A number of 1 to 10, for example, methoxy, ethoxy, butoxy, 2-ethylhexyloxy, etc.), an aryloxy group (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 carbon atoms). It has 6 to 12 carbon atoms, and examples thereof include phenyloxy, 1-naphthyloxy, 2-naphthyloxy and the like.), a heterocyclic oxy group (preferably 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, It preferably has 1 to 12 carbon atoms, and examples thereof include pyridyloxy, pyrazyloxy, pyrimidyloxy, quinolyloxy, etc.), an acyl group (preferably 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably It has 1 to 12 carbon atoms, and examples thereof include acetyl, benzoyl, formyl, pivaloyl, etc.), an alkoxycarbonyl group (preferably 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 carbon atoms). To 12 and include, for example, methoxycarbonyl, ethoxycarbonyl, etc.), Aryl Xycarbonyl group (preferably having 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, and particularly preferably 7 to 12 carbon atoms, and examples thereof include phenyloxycarbonyl and the like. ), an acyloxy group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 to 10 carbon atoms, and examples thereof include acetoxy and benzoyloxy). Acylamino group (preferably). It has 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 to 10 carbon atoms, and examples thereof include acetylamino and benzoylamino.), alkoxycarbonylamino groups (preferably 2 to 10 carbon atoms). 30, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 12 carbon atoms, and examples thereof include methoxycarbonylamino and the like, aryloxycarbonylamino group (preferably 7 to 30 carbon atoms, and more preferably 7 to 20 carbon atoms, particularly preferably 7 to 12 carbon atoms, and examples thereof include phenyloxycarbonylamino and the like, sulfonylamino group (preferably 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, Particularly preferably, it has 1 to 12 carbon atoms, and examples thereof include methanesulfonylamino, benzenesulfonylamino and the like.), a sulfamoyl group (preferably 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, and particularly preferably carbon atoms). The number is 0 to 12, and examples thereof include sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, and phenylsulfamoyl.), a carbamoyl group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms). Particularly preferably, it has 1 to 12 carbon atoms, and examples thereof include carbamoyl, methylcarbamoyl, diethylcarbamoyl and phenylcarbamoyl.), an alkylthio group (preferably 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms). It preferably has 1 to 12 carbon atoms, and examples thereof include methylthio and ethylthio.), an arylthio group (preferably 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and particularly preferably 6 to 12 carbon atoms). And, for example, phenylthio, etc.), a heterocyclic thio group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms), for example pyridylthio, 2- Benzimizolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio, etc.), sulfonyl group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, and particularly preferably having carbon atoms). 1 to 12, and examples thereof include mesyl and tosyl.) Ruffinyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include methanesulfinyl and benzenesulfinyl. ), a ureido group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include ureido, methylureido, phenylureido, etc.), and phosphoric acid. Amido group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include diethylphosphoric acid amide and phenylphosphoric acid amide). A mercapto group, a halogen atom (preferably a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, more preferably a bromine atom, an iodine atom, and particularly preferably a bromine atom), a cyano group, a sulfo group, a carboxyl group. Group, nitro group, trifluoromethyl group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 12 carbon atoms, and as a hetero atom) , For example, nitrogen atom, oxygen atom, sulfur atom, specifically imidazolyl, pyridyl, quinolyl, furyl, thienyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, carbazolyl group, azepinyl group, etc.) A silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms, and examples thereof include trimethylsilyl and triphenylsilyl). Silyloxy group (preferably It has 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms, and examples thereof include trimethylsilyloxy and triphenylsilyloxy).

Among the above, a preferable substituent is a cyano group, a trifluoromethyl group, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an amino group, or a heterocyclic group, and a more preferable substituent is a cyano group or a halogen. An atom, an alkyl group, an aryl group, or a heterocyclic group, a particularly preferable substituent is a halogen atom, an alkyl group, or an aryl group, and a particularly preferable substituent is a bromine atom, an alkyl group, or an aryl group. is there. These substituents may further have a substituent.

CyA represents a 5-membered or 6-membered cyclic group containing a nitrogen atom, and is bonded to iridium via the nitrogen atom. CyA is preferably a 5-membered or 6-membered nitrogen-containing aromatic heterocycle.

CyB represents a 5-membered or 6-membered cyclic group containing a carbon atom, and is bonded to iridium via the carbon atom. CyB is preferably a 5-membered or 6-membered aromatic carbocycle or aromatic heterocycle, and more preferably a 5-membered or 6-membered aromatic carbocycle or nitrogen-containing aromatic heterocycle. A 5-membered or 6-membered aromatic carbocyclic ring is particularly preferable.

CyA and CyB may combine to form a new ring structure. In this case, CyA and CyB are preferably bonded to each other to form a new saturated ring or unsaturated ring, more preferably an unsaturated ring.

Examples of the 5- or 6-membered cyclic group containing a nitrogen atom include pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, quinoline ring, isoquinoline ring, quinoxaline ring, cinnoline ring, phthalazine ring, quinazoline ring, naphthyridine ring. Examples thereof include a ring, an imidazole ring, a pyrazole ring, a triazole ring, a tetrazole ring, an oxazole ring, an oxadiazole ring, a thiazole ring, and a thiadiazole ring. Among these, a pyridine ring, a pyrimidine ring, a pyrazine ring, a quinoline ring, an isoquinoline ring, an imidazole ring, a pyrazole ring, or a triazole ring is preferable, and a pyridine ring, a quinoline ring, an isoquinoline ring, or an imidazole ring is more preferable. It is a ring, particularly preferably a pyridine ring, a triazole ring or an imidazole ring, most preferably an imidazole ring.

Specific examples of the 5- or 6-membered cyclic group containing a carbon atom include benzene ring, naphthalene ring, anthracene ring, carbazole ring, fluorene ring, furan ring, thiophene ring, pyridine ring, pyrimidine ring, pyrazine. Ring, pyridazine ring, quinoline ring, isoquinoline ring, quinoxaline ring, cinnoline ring, phthalazine ring, quinazoline ring, naphthyridine ring, imidazole ring, pyrazole ring, triazole ring, tetrazole ring, oxazole ring, oxadiazole ring, thiazole ring, or , And a thiadiazole ring. Among these, a benzene ring, a naphthalene ring, a pyridine ring, or a pyrimidine ring is preferable, a benzene ring, a pyridine ring, or a pyrimidine ring is more preferable, and a benzene ring is particularly preferable.

The ring formed by combining CyA and CyB preferably forms a benzoquinoxaline ring, a benzoquinoline ring, a dibenzoquinoxaline ring, a dibenzoquinoline ring, or a phenanthridine ring by combining CyA and CyB. It is more preferable to form a benzoquinoline ring, a dibenzoquinoxaline ring, or a phenanthridine ring. The benzoquinoline ring is preferably a benzo[h]quinoline ring. The dibenzoquinoxaline ring is preferably a dibenzo[f,h]quinoxaline ring. The phenanthridine ring is preferably an imidazo[1,2-f]phenanthridine ring.

The ring formed by combining CyA, CyB, and CyA and CyB may have a substituent, or adjacent substituents may combine to form a ring structure, and further has a substituent. May be.

The substituents bonded to CyA, CyB, and the ring formed by bonding CyA and CyB are the same as R ^{1 to} R ⁴⁸ , and the desirable ranges are also the same.

As the aromatic heterocyclic bidentate ligand represented by the general formula (1), those having a structure represented by any one of the general formulas (2) to (15) are particularly preferable. R ^{1 to} R ¹³⁵ each independently represent a hydrogen atom or a substituent. Adjacent substituents may be bonded to each other to form a ring structure. The substituents of R ^{1 to} R ¹³⁵ are the same as those of R ^{1 to} R ⁴⁸ described above, and the desirable range is also the same. Among these, those having the structure of general formulas (2) to (6) are preferable, those having the structure of general formula (3) or (4) are more preferable, and those having the structure of general formula (3) are preferable. Those are particularly preferable.

The cyclometalated iridium complex produced by the present invention will be described.

In the present specification, the cyclometalated iridium complex is characterized by having an aromatic heterocyclic bidentate ligand that forms an iridium-nitrogen bond and an iridium-carbon bond represented by the general formula (1). The cyclometalated iridium complex produced by the present invention is preferably a triscyclometalated iridium complex, more preferably represented by the general formula (16).

In the manufacturing method of the present invention, the heating means is not particularly limited. Any conventional external heating method such as an oil bath, a mantle heater, a block heater or a heating medium circulation type jacket or a microwave irradiation method can be applied.

The production method of the present invention can be carried out in an atmosphere of air or an inert gas (nitrogen, argon, etc.), more preferably in an atmosphere of an inert gas.

The reaction temperature in the production method of the present invention is preferably 50°C to 300°C, more preferably 50°C to 200°C, particularly preferably 100°C to 180°C, and most preferably 120°C to 160°C. Is.

The reaction time in the production method of the present invention is usually 1 hour to 72 hours, preferably 1 hour to 48 hours, more preferably 3 hours to 24 hours, and particularly preferably 5 hours to 17 hours. ..

The production method of the present invention is usually carried out under normal pressure, but may be carried out under pressure or under reduced pressure if necessary.

In the production method of the present invention, it is also preferable to carry out while distilling off by-product acetic acid from the reaction system.

In this embodiment, it is preferable to use a reaction solvent in order to smoothly proceed the reaction. The reaction solvent is not particularly limited, but alcohol solvents, protic solvents, aprotic solvents, hydrocarbon solvents, nitrile solvents, ionic solvents and the like are preferably used. The boiling point of the reaction solvent used is preferably 100°C to 300°C, more preferably 160°C to 250°C, and particularly preferably 180°C to 230°C. Examples of such a reaction solvent include 2-ethoxyethanol, DMF (N,N-dimethylformamide), diglyme, dodecane, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3- Examples include butanediol and glycerin. Among them, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol and glycerin are preferable. These reaction solvents can be used alone or as a mixed solvent containing two or more kinds.

The amount of the aromatic heterocyclic ligand used in the production method of the present invention is not particularly limited, but is preferably 3 to 10 times mol, more preferably 3 to 8 times mol, and more preferably 3 to 6 times mol, based on iridium acetate. Is particularly preferable. The number of moles of iridium acetate can be calculated from the iridium content rate.

The cyclometalated iridium complex obtained by the present invention can be processed into a highly pure product after being treated according to a usual post-treatment and then purified if necessary. As the method of the post-treatment, for example, extraction, cooling, crystallization by adding water or an organic solvent, operation of distilling off the solvent from the reaction mixture, and the like can be performed alone or in combination. As a purification method, recrystallization, distillation, sublimation, column chromatography or the like can be performed alone or in combination.

The cyclometalated iridium complex produced by the present invention does not contain halogen (chlorine or the like) that adversely affects the characteristics of the light emitting device, and can be contained in the light emitting layer of the light emitting device or a plurality of organic compound layers including the light emitting layer. It is possible to obtain a light-emitting element that is more excellent in light emission efficiency and durability than ever before.

Next, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

The structures of the compounds appearing in the examples are shown below.

The iridium acetates A to E (manufactured by Furuya Metal Co., Ltd.) used in the present invention were analyzed by a mass spectrometer. Iridium acetate was dissolved in methanol, and after 24 hours, mass spectrometry was performed. The specific analysis conditions are as follows.

Ionization method: Electrospray ionization method Cone voltage: 50V
Capillary voltage: 4kV
Ion source temperature: 150℃
Desolvation temperature: 200°C
Desolvation gas flow rate: 160 L/Hr
Cone gas flow rate: 60 L/Hr
Gas: Nitrogen gas Device name: Waters Micromass ZQ

As a result of mass spectrometry, iridium acetates A to E were classified into two types.
(1) A peak of m/z=947±1 was observed (iridium acetate A to D)
(2) No peak of m/z=947±1 was observed (iridium acetate E)

Next, regarding the iridium acetates A to D in which the peak at m/z=947±1 was observed, when the peak intensity at m/z=947±1 was set to 100%, the peak intensity at m/z=620±1. Can be summarized as follows.
Iridium acetate A: 7.0%
Iridium acetate B: 19.3%
Iridium acetate C: 28.9%
Iridium acetate D: 50.0%

As a result of the above-mentioned mass spectrometry, a peak corresponding to the molecular weight of Ir(CH ₃ COO) ₃ used in Patent Document 1 was not detected.

A cyclometalated iridium complex was synthesized using these iridium acetates A to E. Examples will be shown below.

Example 1 (Synthesis of Compound (1))
Iridium acetate A (50 mg), ligand L-1 (158 mg), and ethylene glycol (2.5 ml) were heated and reacted at 150° C. for 17 hours under an argon atmosphere. After cooling to room temperature, the reaction solution was filtered, and the obtained yellow solid was washed with methanol. This yellow solid was compound (1), and the isolated yield was 72%. Furthermore, the reaction solution was extracted with ethyl acetate and water, and the organic layer was concentrated to dryness. The obtained yellow solid was purified by silica gel column chromatography (eluent: mixed solvent of ethyl acetate and hexane) to obtain compound (1) in an isolated yield of 7%. The total isolated yield of the compound (1) was 79%.

Example 2 (Synthesis of Compound (1))
Compound (1) was obtained in the same manner as in Example 1 except that iridium acetate B was used instead of iridium acetate A. The isolated yield of the compound (1) was 76%.

Example 3 (Synthesis of Compound (1))
Compound (1) was obtained in the same manner as in Example 1 except that iridium acetate C was used instead of iridium acetate A. The isolated yield of the compound (1) was 67%.

Example 4 (Synthesis of Compound (1))
Compound (1) was obtained in the same manner as in Example 1 except that iridium acetate D was used instead of iridium acetate A. The isolated yield of the compound (1) was 58%.

Comparative Example 1 (Synthesis of Compound (1))
Compound (1) was obtained in the same manner as in Example 1 except that iridium acetate E was used instead of iridium acetate A. The isolated yield of the compound (1) was 48%.

Example 5 (Synthesis of Compound (2))
Iridium acetate C (50 mg), ligand L-2 (133 mg), and ethylene glycol (2.5 ml) were heated and reacted at 150° C. for 5 hours under an argon atmosphere. After cooling to room temperature, the reaction solution was filtered, and the obtained yellow solid was washed with methanol. This yellow solid was compound (2), and the isolated yield of compound (2) was 79%.

From the above results, when iridium acetate E in which the peak of m/z=947±1 is not observed in mass spectrometry is used, it is compared with iridium acetate A to D in which the peak of m/z=947±1 is observed in mass spectrometry. The yield of the target compound (1) is low. Next, when comparing iridium acetates A to D where a peak at m/z=947±1 was observed by mass spectrometry, when the peak intensity at m/z=947±1 was 100% by mass spectrometry, m/z=947±1. It was revealed that the desired cyclometalated iridium complex can be produced in higher yield by using iridium acetate having a peak intensity of z=620±1 of less than 50%.

Claims (8)

A method for producing a cyclometalated iridium complex by reacting iridium acetate with an aromatic heterocyclic bidentate ligand represented by the general formula (1), wherein the iridium acetate is used for mass spectrometry of ions by mass spectrometry. A method for producing a cyclometalated iridium complex, which comprises using an iridium compound showing a peak at a mass-to-charge ratio (m/z)=947±1 when an applied voltage for introducing into the part is 30 to 50V.
(In the general formula (1), N represents a nitrogen atom, C represents a carbon atom, H represents a hydrogen atom, CyA represents a 5-membered or 6-membered cyclic group containing a nitrogen atom, and CyB represents It represents a 5-membered or 6-membered cyclic group containing a carbon atom, and CyA and CyB may combine to form a ring structure.) Iridium acetate whose peak intensity at m/z=620±1 is less than 50% is used when the peak intensity at m/z=947±1 is 100%, and the cyclometal according to claim 1. For producing an iridium complex. The method for producing a cyclometallated iridium complex according to claim 1 or 2, wherein the ionization method in mass spectrometry is an electrospray ionization (ESI) method. The method for producing a cyclometalated iridium complex according to any one of claims 1 to 3, wherein the aromatic heterocyclic bidentate ligand is one of the general formulas (2) to (6). ..
(In formulas (2) to (6), R ^{1 to} R ⁴⁸ each independently represent a hydrogen atom or a substituent.) The method for producing a cyclometalated iridium complex according to claim 1, wherein the cyclometalated iridium complex is a triscyclometalated iridium complex. Iridium acetate characterized by exhibiting a peak at a mass-to-charge ratio (m/z) of 947±1 when an applied voltage for introducing ions into a mass spectrometric section is 30 to 50 V in mass spectrometry. 7. The iridium acetate according to claim 6, wherein the peak intensity at m/z=620±1 is less than 50% when the peak intensity at m/z=947±1 is 100%. Iridium acetate according to claim 6 or 7, wherein the ionization method in mass spectrometry is an electrospray ionization (ESI) method.