IRIDIUM COMPOUND AND METHOD FOR PRODUCING IRIDIUM COMPLEX BY USING IRIDIUM COMPOUND

Abstract

The present invention provides an iridium compound useful as a raw material compound for producing a cyclometalated iridium complex, the iridium compound being represented by the following General Formula (1). The iridium compound of the present invention is particularly useful as a raw material for imidazole-based cyclometalated iridium complexes among cyclometalated iridium complexes.

##STR00001##

(In General Formula (1), Ir represents an iridium atom, O represents an oxygen atom, X represents a halogen atom, and Y represents a counter cation; and R.sup.1 and R.sup.2 each independently represent an alkyl group with a carbon number of 1 or more and 10 or less, with the proviso that only one of R.sup.1 and R.sup.2 is a branched alkyl group.)

Claims

1. An iridium compound which is represented by the following General Formula (1): ##STR00013## (in General Formula (1), Ir represents an iridium atom, O represents an oxygen atom, X represents a halogen atom, and Y represents a counter cation; and R.sup.1 and R.sup.2 each independently represent an alkyl group with a carbon number of 1 or more and 10 or less, with the proviso that only one of R.sup.1 and R.sup.2 is a branched alkyl group).

2. The iridium compound according to claim 1, wherein one of R.sup.1 and R.sup.2 is a methyl group, and the other one of R.sup.1 and R.sup.2 is a branched alkyl group with a carbon number of 3 or more and 10 or less.

3. The iridium compound according to claim 1, wherein one of R.sup.1 and R.sup.2 is an isopropyl group.

4. The iridium compound according claim 1, wherein X represents a chlorine atom or a bromine atom.

5. A method for producing an iridium complex by reacting a raw material including an iridium compound with a ligand, comprising producing an iridium complex by reacting the raw material with the ligand, the raw material being the iridium compound defined in claim 1, the ligand being a ligand represented by the following General Formula (2), the iridium complex being represented by the following General Formula (3): ##STR00014## (in General Formulae (2) and (3), Ir represents an iridium atom; N represents a nitrogen atom; R.sup.3 to R.sup.9 each independently represent a hydrogen atom or a substituent; and adjacent substituents are optionally linked together to further form a ring structure).

6. The iridium compound according to claim 2, wherein one of R.sup.1 and R.sup.2 is an isopropyl group.

7. The iridium compound according claim 2, wherein X represents a chlorine atom or a bromine atom.

8. The iridium compound according claim 3, wherein X represents a chlorine atom or a bromine atom.

9. A method for producing an iridium complex by reacting a raw material including an iridium compound with a ligand, comprising producing an iridium complex by reacting the raw material with the ligand, the raw material being the iridium compound defined in claim 2, the ligand being a ligand represented by the following General Formula (2), the iridium complex being represented by the following General Formula (3): ##STR00015## (in General Formulae (2) and (3), Ir represents an iridium atom; N represents a nitrogen atom; R.sup.3 to R.sup.9 each independently represent a hydrogen atom or a substituent; and adjacent substituents are optionally linked together to further form a ring structure).

10. A method for producing an iridium complex by reacting a raw material including an iridium compound with a ligand, comprising producing an iridium complex by reacting the raw material with the ligand, the raw material being the iridium compound defined in claim 3, the ligand being a ligand represented by the following General Formula (2), the iridium complex being represented by the following General Formula (3): ##STR00016## (in General Formulae (2) and (3), Ir represents an iridium atom; N represents a nitrogen atom; R.sup.3 to R.sup.9 each independently represent a hydrogen atom or a substituent; and adjacent substituents are optionally linked together to further form a ring structure).

11. A method for producing an iridium complex by reacting a raw material including an iridium compound with a ligand, comprising producing an iridium complex by reacting the raw material with the ligand, the raw material being the iridium compound defined in claim 4, the ligand being a ligand represented by the following General Formula (2), the iridium complex being represented by the following General Formula (3): ##STR00017## (in General Formulae (2) and (3), Ir represents an iridium atom; N represents a nitrogen atom; R.sup.3 to R.sup.9 each independently represent a hydrogen atom or a substituent; and adjacent substituents are optionally linked together to further form a ring structure).

Description

DESCRIPTION OF EMBODIMENTS

[0072] Hereinafter, an embodiment of the present invention will be described in detail, but the embodiment is illustrative, and the present invention is not limited thereto.

[0073] In this embodiment, the iridium compound (Ir-1) of Chemical Formula 6 was used as a raw material, and reacted with the following 2-phenylimidazole derivative (L-1) to produce an imidazole-based cyclometalated iridium complex (T-1).

##STR00011##

[0074] [Production of Iridium Compound (Ir-1)]

[0075] 40.6 g (115 mmol) of iridium trichloride trihydrate and 530 ml of pure water were added in a three-necked flask, and dissolved, 45.7 g (357 mmol) of 5-methyl-2,4-hexanedione was subsequently added, the mixture was reacted at 95 C. for 1 hour, and 47.5 g (475 mmol) of potassium carbonate was added to the mixture little by little to adjust the pH to about 8. Further, the mixture was heated and reacted for 5 hours. After the reaction, the reaction product was left standing overnight, unreacted 5-methyl-2,4-hexanedione was extracted and removed from the aqueous layer of the supernatant by use of hexane, an iridium compound (Ir-1) was subsequently extracted with ethyl acetate, and the extract was concentrated and dried to obtain 12 g of an orange crude crystal of the iridium compound (Ir-1). Further, the crude crystal was subjected to column purification to obtain 10.2 g of an orange crystal of the iridium compound (Ir-1). The isolation yield was 16%.

[0076] [Production of Iridium Complex]

[0077] 167.0 mg (0.3 mmol) of the iridium compound (Ir-1) produced as described above, 396.0 mg (1.8 mmol) of a 2-phenylimidazole derivative (L-1) and 5 ml of ethylene glycol as a solvent were added in a three-necked flask, and the mixture was heated and reacted in an argon atmosphere at 180 C. for 17 hours. After completion of the reaction, the reaction solution was cooled to room temperature, and the precipitated solid was washed with methanol to obtain an imidazole-based cyclometalated iridium complex (T-1). The isolation yield was 73%. The product was analyzed by .sup.1H-NMR, and identified.

COMPARATIVE EXAMPLE

[0078] In the comparative example, bis(acetylacetonate)dichloroiridium (III) acid sodium in Patent Document 1 was used as a raw material, and reacted with the following 2-phenylimidazole derivative (L-1) to produce an imidazole-based cyclometalated iridium complex (T-1).

##STR00012##

[0079] 145.3 mg (0.3 mmol) of bis(acetylacetonate)dichloroiridium (III) acid sodium, 396.0 mg (1.8 mmol) of a 2-phenylimidazole derivative (L-1) and 5 ml of ethylene glycol were added in a three-necked flask, and the mixture was heated and reacted in an argon atmosphere at 180 C. for 17 hours. After completion of the reaction, the reaction solution was cooled to room temperature, and the precipitated solid was washed with methanol to obtain an imidazole-based cyclometalated iridium complex (T-1). The isolation yield was 52%.

[0080] From the above results, it was confirmed that imidazole-based cyclometalated iridium (T-1) was produced with a high yield by use of the iridium compound (Ir-1) of this embodiment. Comparison between this embodiment and the comparative example shows that when the iridium compound (Ir-1) of this embodiment was used, the yield was higher by 40% or more than when bis(acetylacetonate)dichloroiridium (III) acid sodium of the comparative example, which is a conventional compound, was used.

INDUSTRIAL APPLICABILITY

[0081] The present invention allows a cyclometalated iridium complex to be efficiently produced. Particularly, an imidazole-based cyclometalated iridium complex can also be produced with a high yield. The present invention provides a raw material suitable for producing a cyclometalated iridium complex to be used as a phosphorescent material which is used for organic electroluminescent (EL) devices, organic electrochemiluminescent (ECL) devices, luminescent sensors, photosensitizing pigments, photocatalysts, luminescent probes, various light sources and the like.