WO2004043974A1

WO2004043974A1 - Production of iridium complexes

Info

Publication number: WO2004043974A1
Application number: PCT/JP2003/014192
Authority: WO
Inventors: Yuji Nakayama; Yoshimasa Matsushima; Yoji Hori
Original assignee: Takasago International Corp; Takasago Perfumery Industry Co
Current assignee: Takasago International Corp
Priority date: 2002-11-12
Filing date: 2003-11-07
Publication date: 2004-05-27
Anticipated expiration: 2005-05-12
Also published as: AU2003276717A1; TWI253449B; TW200418865A; JP2004161661A

Abstract

The invention relates to a process for producing a trivalent hexadentate ortho-metallated iridium complex with an iridium compound and a coordination compound as starting materials, which is characterized in that a monovalent iridium dinulear complex represented by the following formula (I)is used:(wherein A represents a non-conjugated diene compound; and X represents a halogen atom).According to the invention, it is possible to carry out the successive reactions in the same reaction vessel (i.e., one-pot reaction) by using the complex produced in the above process in the next step without isolation and purification.

Description

DESCRIPTION PRODUCTION OF IRIDIUM COMPLEXES

BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION

The present invention relates to a process for producing a trivalent hexadentate ortho- etallated iridium complex being useful as a material for a light-emitting device and the like.

2. RELATED ART

Organic electroluminescence (EL) devices have received attention in view of the practical use as display devices of the next generation including an ultra-slimline display or electronic paper since they can emit light of high luminance at a lower voltage.

By using an organic EL device, it is possible to form a slimflat-panel displaywithoutbacklight as in liquidcrystals because the EL device has a higher response speed than liquid crystals and emits spontaneously. The organic EL device is an emission device utilizing electroluminescence (EL) based on the same principle as in LED and characterized by using an organic fluorescent substance as an emission material.

A variety of emission materials for organic EL devices have been developed, and particularly trivalent hexadentate ortho-metallated iridium complexes such as bis (2-phenylpyridinato-N,C²') iridium acetylacetonate (re- ferred to as Compound 3-1 below) and tris (2-phenylpyridinato-N, C²' ) iridium (referredto as Compound 5-1 below) have received attention since they emit phosphorescence from a triplet excitation state with a characteristic higher quantum efficiency than the fluorescent emission and its wavelength of emission can optionally be adjusted by changing the chemical structure of the ligand. For example, a light-emitting device using Compound 5-1 as discussed below has a value as high as 9% in an external quantum efficiency for green-light emission (see Non-patent document 1). Bis [2- (2' -benzothienyl) pyridinato-N, C³' ) iridium (III) acetylacetonate (referred to as Compound 3-7 below) has been reported to be a red phosphorescence-emitting material with very high quantum efficiency and color purity (see Non-patent document 2) . From the above fact, research on the design for peripheral devices as well as an efficient method for synthesis of the complexes have now actively be conducted aiming at actual use of them.

Inproductionof a trivalenthexadentate ortho-metallated iridium complex, a variety of processes have been reported. For example, a process in which iridium (III) chloride hydrate is allowed to react with a large amount of a ligand in the presence of a silver salt and water at high temperature has been known (see Patent document 1 as an example of recent year) . According to the report on this process, the objective product is obtained in 10% to 82% yield.

As another recent example, a process in which iridium

(III) acetylacetonate is allowed to react with a theoretical amount of a ligand in glycerol at high temperature has been known (Patent document 2), wherein it has been reported the product is produced in 75% yield. Though the yield is moderate, theprocess requires a strict reaction condition, andtheprocess is not able to introduce different kinds of ligands to the iridium complex (for example, the complex of the formula (V)) .

In improving this process, a process in which a trivalent hexadentate ortho-metallated iridium dinuclear complex of the formula (II) is synthesized by the reaction of iridium(III) chloride hydrate with a theoretical amount of a ligand according to the so-called Nonoyama process (see Non-patent document 3) , followed by reaction with acetylacetone in the presence of a base to give an acetylacetonate complex, which is then allowed to react with a theoretical amount of a ligand in glycerol at a high temperature to give a trivalent hexadentate ortho-metallated iridium complex of the formula (V) (see Non-patent documents 4 and 5 and Patent document 3 as examples in recent years) has be reported. In this process, the reported yield at the 1st step is 75% or higher, 75-90% at the 2nd step, and 85% at the 3rd step (see Non-patent document 5) . According to this process, the complexes containing the different ligands

(formula (III) ) and the complexes containing the same ligands (formula (V) ) can be produced respectively from the common raw materials in good yields. There are some problems therein, however, that the reaction has to be carried out in multi steps and requires complicated procedures for isolation and purification of respective intermediates and the objective compounds, which result in the loss of the objective compounds.

REFERENCES

Patent document 1 WO 02/02714 Patent document 2 WO 02/15645 Patent document 3 JP-A No.105055

Non-patent document 1: Baldo M.A. et al . , Appl. Phys . Lett.,

1999,^' 75, 4-6 Non-patent document 2: Adachi, C. et al . , Appl. Phys. Lett.,

2001, 78, 1622-1624 Non-patent document 3: M. Nonoyama, Bull. Chem. Soc. Jpn.,

1974, 47(3), 767-768 Non-patent document 4: S. Lamansky, et al . , J. Am. Chem. Soc,

2001, 123, 4304-4312 Non-patent document 5: S. Lamansky, et al . , Inorg. Chem.,

2001, 40, 1704-1711 SUMMARY OF THE INVENTION Trivalent hexadentate ortho-metallated iridium complexes have been expected as light-emitting materials for organic electroluminescence (EL) devices. The production method thereof, however, has to pass through complicated steps, and accordingly it has been desired that a more convenient process for producing such complexes in high yield will be established toward the practical use of the complexes as the light-emitting material.

An object of the present invention is to provide a convenient and efficient process for producing a trivalent hexadentate ortho-metallated iridium complex being useful as a material for a light-emitting device.

Thepresent inventors have conducted research assiduously to develop an efficient and convenient process for producing a trivalent hexadentate ortho-metallated iridium dinuclear complex in a milder condition. As a result, they have found that the reaction using a monovalent iridium dinuclear complex represented by the formula (I) as a starting material gives a trivalent hexadentate ortho-metallated iridium dinuclear complex represented by the formula (II) in a milder condition efficiently in quantitative yield within a short period of time .

After isolation and purification, the complex of the formula (II) produced in this process can be applied to the synthesis of other complexes. The present inventors further conducted research assiduously to establish a commercially applicable process for producing iridium complexes, and as a result they have found that the trivalent hexadentate ortho-metallated iridium dinuclear complex of the formula (II) produced in this reaction can be applied without isolation and purification from the reaction mixture to the reaction with a compound of the formula (VII) or (VIII) and a base or a compound of the formula (VI) and a silver salt placed in the same reaction vessel to give the complex in which the ligands are the same with each other (the formula (V) ) as the complex (the formula e (III) and (IV)), in which the ligands are different, in a conventional way in high yield, wherein the individual products can optionally be produced separately. Thus, the invention has been completed based on the finding mentioned above.

Thus, the invention provides a process for producing a trivalent hexadentate ortho-metallated iridium complex with an iridium compound and a coordination compound as starting materials, which is characterized in that a monovalent iridium dinuclear complex represented by the following formula (I) is used as the raw iridium compound:

(wherein A represents a non-conjugated diene compound; and X represents a halogen atom) .

More particularly, the invention provides a process for producing a trivalent hexadentate ortho-metallated iridium dinuclear complex represented by the formula (II) :

(wherein the ring B represents an optionally substituted aryl group or heteroaryl group; the ring C represents an optionally substituted nitrogen-containing aryl group; the rings B and C may be taken with each other to form a fused ring; X has the same meanings as mentioned above) characterized in that reacting a monovalent iridium dinuclear complex of the formula (I) with a compound of the formula (VI) :

(wherein the rings B andC eachhave the samemeanings asmentioned above)

The process of the invention can be shown briefly by the following reaction formula.

Formula (I) + Formula (VI) —» Formula (II) The invention also provides a process for converting the complex of the formula (II) produced in the above process into a trivalent hexadentate ortho-metallated iridium complex representedby the formula (III), (IV) or (V) . In this reaction, the complex of the formula (II) without isolating and purifying from the reaction mixture can be used as an intact reaction mixture in the next step. This is another major characteristic in the invention.

Briefly, the invention provides a process for producing a trivalent hexadentate ortho-metallated iridium complex represented by the formula (III) :

(wherein R¹ and R³ each represent independently an alkyl group, alkoxy group, aryl group or heteroaryl group; R² represents a hydrogen atom, alkyl group, aryl group or heteroaryl group;

R¹ and R² or R² and R³ may be taken together with the adjacent carbon atom to form a ring; the rings B and C, each has the same meanings as mentioned above) characterized in that reacting a monovalent iridium dinuclear complex of the formula (I) with a compound of the formula (VI) to give a compound of the formula (II), followed by reacting the compound of the formula (II) with a compound of the formula

(VII) :

(wherein R¹, R² and R³ each have the same meanings as mentioned above) . This process of the invention can be shown briefly by the following reaction formulae.

1st step: Formula (I) + Formula (VI) —> Formula (II) 2nd step: Formula (II) + Formula (VII) -» Formula (III) This process of the invention may be carried out step by step or successively. When the reaction is carried out successively, the reaction may be conduced in the same reaction vessel, i.e., one-pot reaction, by adding a compound of the formula (VII) into the reaction mixture of the 1st step.

In addition, the invention also provides a process for producing a trivalent hexadentate ortho-metallated iridium complex represented by the formula (IV) :

(wherein the rings B andC eachhave the samemeanings as mentioned above, and the ring D represents an optionally substituted pyridyl group. Alternatively, the rings B and C may be taken with each other to form a fused ring) characterized in that reacting a monovalent iridium dinuclear complex of the formula (I) with a compound of the formula (VI) , followed by the reaction with a compound of the formula (VIII) :

(wherein the ring D has the same meanings as mentioned above) This process of the invention can be shown briefly by the following reaction formulae.

1st step: Formula (I) + Formula (VI) —> Formula (II) 2nd step: Formula (II) + Formula (VIII) —> Formula (IV) This process of the invention may be carried out step by step or successively. When the reaction is carried out successively, the reaction may be conduced in the same reaction vessel, i.e., one-pot reaction, by adding a compound of the formula (VIII) into the reaction mixture of the 1st step.

In addition, the invention also provides a process for producing a trivalent hexadentate ortho-metallated iridium complex represented by the formula (V) :

(wherein the rings B andC each have the samemeanings asmentioned above) characterized in that reacting a monovalent iridium dinuclear complex of the formula (I) with a compound of the formula (VI) to produce a compound of the formula (II) , followed by the reaction with a silver salt and a compound of the formula (VI) . This process of the invention can be shown briefly by the following reaction formulae.

1st step: Formula (I) + Formula (VI) -» Formula (II) 2nd step: Formula (II) + Silver salt + Formula (VI)

—> Formula (V) This process of the invention may be carried out step by step or successively. When the reaction is carried out successively, the reaction may be conduced in the same reaction vessel, i.e., one-pot reaction, by adding a silver salt into the reaction mixture of the 1st step.

The processes for producing trivalent hexadentate ortho-metallated iridium complexes of the present invention are characterized by using a monovalent iridium dinuclear complex represented by the formula (I) as the raw material. The processes of the present invention are also characterized in that the objective trivalent hexadentate ortho-metallated iridium complexes can be produced in the same reaction vessel, i.e., one-pot reaction, using the monovalent iridium dinuclear complex represented by the formula (I) as the raw material. According to the processes of the present invention, iridium complexes containing a variety of coordination compounds as ligands, such as trivalent hexadentate ortho-metallated iridium complexes represented by the following formula (II),

formula (III)

formula (IV) ,

or formula (V) can be produced.

(wherein the ring B represents an optionally substituted aryl group or heteroaryl group; the ring C represents an optionally substituted nitrogen-containing aryl group; the ring D represents an optionally substituted pyridyl group; the rings B and C may be taken with each other to form a fused ring; X represents a halogen atom; R¹ and R³ each represents independently an alkyl group, alkoxy group, aryl group or heteroaryl group; R² represents a hydrogen atom, alkyl group, aryl group or heteroaryl group; R¹ and R² or R² and R³ may be taken together with the adjacent carbon atom to form a ring) 3. DETAILED DESCRIPTION OF THE INVENTION

The followings, firstly, will explain the monovalent iridium dinuclear complexes of the formula (I) used as the starting compounds in the manufacturing process of the present invention.

A non-conjugated diene compound represented by A in the formula (I) may be cyclic or acyclic ones and may have a substituent or substituents as long as they have no adverse effect. The cyclic diene compound includes any one of monocyclic, polycyclic, condensed cyclic, and cross-linked cyclic. The preferred non-conjugated diene compound represented by A includes, for example, of those having 5 to 20 carbon atoms, preferably 5 to 10 carbon atoms, with a cyclic non-conjugated diene compound being particularly preferred. Specific examples of the preferred non-conjugated diene compounds include cyclic compounds such as 1, 5-cyclooctadiene (cod), and bicyclo [2.2. l]hepta-2, 5-diene (nbd) .

Ahalogen atomrepresentedbyX inthe formula (I) includes, for example, fluorine atom, chlorine atom, bromine atom, and iodine atom, with chlorine atom being preferred. The preferredmonovalent iridium dinuclear complexes of the formula (I) may be represented by the following formula (IX) or(X) :

(wherein X has the same meanings as mentioned above)

The followings will explain the trivalent hexadentate ortho-metallated iridium complexes represented by the formula e (II) to (V) which can be produced in the present invention.

In the formula (II), the optionally substituted aryl group or heteroaryl group represented by the ring B includes aryl groups, substituted aryl groups, heteroaryl groups and substituted heteroaryl groups.

An aryl group is exemplified by a monocyclic, polycyclic or condensed cyclic aryl group having 6 to 14 carbon atoms. Concrete examples of the aryl group include phenyl, naphthyl, anthryl, and the like.

A heteroaryl group is exemplified by a five- or six-membered monocyclic, polycyclic or condensed cyclic aromatic heterocyclic group containing, for example, 1 to 3 nitrogen atoms, oxygen atoms and/or sulfur atoms as heteroatoms . Concrete examples of the heteroaryl group include pyridyl, imidazolyl, thiazolyl, furyl, benzofuryl, thienyl, benzothienyl, and the like.

A substituted aryl group includes the aryl group as mentioned above in which at least one of the hydrogen atoms is substitutedbya substituent . Asubstitutedheteroaryl group includes the heteroaryl group as mentioned above in which at least one of the hydrogen atoms is substituted by a substituent .

The substituents in these groups include alkyl groups, alkenyl groups, alkynyl groups, aryl groups, heteroaryl groups, alkoxy groups, alkylthio groups, a cyano group, acyl groups, alkyloxycarbonyl groups, a nitro group, halogen atoms, alkylenedioxy groups, and the like. The alkyl group may be a straight or branched chain or cyclic group having, for example, 1 to 15 carbon atoms, preferably 1 to 6 carbon atoms. Concrete examples of the alkyl group include methyl, ethyl, n-propyl, 2-propyl, n-butyl, 2-butyl, isobutyl, tert-butyl, n-pentyl, 2-pentyl, tert-pentyl, 2-methylbutyl, 3-methylbutyl, 2, 2-dimethylpropyl, n-hexyl, 2-hexyl, 3-hexyl, tert-hexyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 2-methylpentan-3-yl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like. The alkenyl group may be a straight or branched chain alkenyl group of for example 2 to 6 carbon atoms. Concrete examples of the alkenyl group include ethenyl, propenyl, 1-butenyl, 2-butenyl, pentenyl, hexenyl, and the like. The alkynyl group may be a straight or branched chain alkynyl group having, for example, 2 to 5 carbon atoms. Concrete examples of the alkynyl group include ethynyl, 1-propynyl, 3-propynyl, 1-butynyl, 3-butynyl, pentynyl, and the like. The aryl group maybe a straight orbranched chain aryl group having, for example, monocyclic, polycyclic or condensed cyclic aryl groups of 6 to 14 carbon atoms. Concrete examples of the aryl group include phenyl, naphthyl, anthryl, and the like. The heteroaryl group may be a straight or branched chain heteroaryl group having, for example, five- or six-membered monocyclic, polycyclic or condensed cyclic aromatic heterocyclic group containing 1 to 3 heteroatoms, e.g., nitrogen atom, oxygen atom, sulfur atom, etc., specifically, pyridyl, imidazolyl, thiazolyl, furyl, benzofuryl, thienyl, benzothienyl, and the like.

The alkoxy group maybe a straight or branched chain alkoxy group having, for example, 1 to 6 carbon atoms . Concrete examples of the alkoxy group include methoxy, ethoxy, n-propoxy, 2-propoxy, n-butoxy, sec-butoxy, tert-butoxy, pentyloxy, hexyloxy, and the like. The alkylthio group may be a straight or branched chain alkylthio group of, for example, 1 to 6 carbon atoms. Concrete examples of the alkylthio group include methylthio, ethylthio, n-propylthio, 2-propylthio, n-butylthio, sec-butylthio, tert-butylthio, pentylthio, hexylthio, and the like. The acyl group may be a straight or branched chain or cyclic acyl group, for example, the acyl group derived from a carboxylic acid of 1 to 7 carbon atoms. Concrete examples of the acyl group include formyl, acetyl, propionyl, butyryl, pentanoyl, hexanoyl, benzoyl, and the like. The alkyloxycarbonyl group includes straight or branched chain alkyloxycarbonyl groups of for example 2 to 7 carbon atoms. Concrete examples of the alkyloxycarbonyl groups include methyloxycarbonyl, ethyloxycarbonyl, propyloxycarbonyl, n-butyloxycarbonyl, tert-butyloxycarbonyl, pentyloxycar- bonyl, hexyloxycarbonyl, and the like. The halogen atom includes, for example, fluorine atom, chlorine atom, bromine atom, and iodine atom. The alkylenedioxy group includes those of for example 1 to 3 carbon atoms, specifically, for example, methylenedioxy, ethylenedioxy, propylenedioxy, and the like.

A nitrogen-containing aryl group in the ring C means the heteroaryl group containing at least one nitrogen atom as heteroatom in the ring, which may further contain 1 or 2 heteroatom (s) such as nitrogen atom, oxygen atom or sulfur atom, including five- or six-membered monocyclic, polycyclic or condensed cyclic aromatic heterocyclic group, wherein at least one of the nitrogen atoms is placed so as to coordinate with the iridiumatom. The nitrogen-containing aryl group includes, for example, pyridyl, quinolyl, and the like.

The nitrogen-containing aryl group in the ring C may be substituted, and the substituted nitrogen-containing aryl group includes those as mentioned above in which at least one hydrogen atom may be substituted by a substituent. The substituent may be the same as that exemplified in the substituted aryl and heteroaryl groups in the ring B.

The ring which is formed by combination of the ring B and the ring C includes fused rings such as benzoquinoline .

The preferred example of the trivalent hexadentate ortho-metallated iridium complexs of the formula (II) produced by the process of the present invention includes those represented by the following formula (XI) :

(wherein R⁸, R⁹, R¹⁰, and R¹¹ each represents independently a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group, alkylthio group, a cyano group, acyl group, alkyloxycarbonyl group, a nitro group, or halogen atom; X represents a halogen atom; the ring B has the same meanings as mentioned above; the ring B may be taken with the pyridyl group binding to the ring B to form a ring)

The alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group, alkylthio group, acyl group, and alkyloxycarbonyl group represented by R⁸, R⁹, R¹⁰, and R¹¹ in the formula (XI) may have an additional substituent or substituents, which may be exemplified by those mentioned in the substituted aryl or heteroaryl groups in the formula (II) . The halogen atom represented by X in the formula (XI) is also as mentioned above.

The preferred ring B includes phenyl group, substituted phenyl group, naphthyl group, substitutednaphthyl group, furyl group, substituted furyl group, benzofuryl group, substituted benzofuryl group, thienyl group, substituted thienyl group, benzothienyl group, substituted benzothienyl group, and the like. The substituent on the substituted phenyl group, substituted naphthyl group, substituted furyl group, substituted benzofuryl group, substituted thienyl group, and substituted benzothienyl group may be exemplified by those mentioned in the substituted aryl group or heteroaryl group in the formula (II) .

Specific examples of the trivalent hexadentate ortho-metallated iridium complexs representedby the formula (II) include the following compounds (Il-i) to (II-xvi) .

π-xϋ

In the trivalent hexadentate ortho-metallated iridium complexs represented by the formula (III) :

(wherein the rings B and C, R , R² and R each has the same meanings as mentioned above) produced by the present invention, the respective groups, i.e., the ring B, the ring C, alkyl group, alkoxy group, aryl group, and heteroaryl group, are the same as described in the formula

(II) . Such groups may further be substituted by a substituent or substituents including those as mentioned'in the substituted aryl or heteroaryl groups in the formula (II) as mentioned above . The preferred substituent includes halogen atoms such as fluorine atom, chlorine atom andbromine atom, which exemplifies substituents such as haloalkyl group, haloalkoxy group, haloaryl group, and halogenated heteroaryl group.

An alkyl group represented by R¹, R² and R³ in the formula

(III) may be a straight or branched chain or cyclic group, for example, alkyl group having 1 to 6 carbon atoms. Concrete examples of the alkyl group include methyl, ethyl, n-propyl, 2-propyl, n-butyl, 2-butyl, isobutyl, tert-butyl, n-pentyl, 2-pentyl, tert-pentyl, 2-methylbutyl, 3-methylbutyl, 2, 2-dimethylpropyl, n-hexyl, 2-hexyl, 3-hexyl, tert-hexyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 2-methylpentan-3-yl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like. halogenated alkyl group includes, for example, the above-mentioned alkyl groups having 1 to 6 carbon atoms halogenated by one or two or more halogen atom(s) (e.g., fluorinated, chlorinated, brominated, or iodinated) . Concrete examples of the halogenated alkyl group include chloromethyl, bromomethyl, trifluoromethyl, 2-chloroethyl, 3-chloropropyl, 3-bromopropyl, 3, 3, 3-trifluoropropyl, and the like. An aryl group includes, for example, the aryl group having of 6 to 14 carbon atoms. Concrete examples of the aryl group include phenyl, naphthyl, anthryl, and the like. A heteroaryl group is exemplified by a five- or six-membered monocyclic or polycyclic aromatic heterocyclic group containing, for example, 1 to 3 nitrogen atoms, oxygen atoms and/or sulfur atoms as heteroatoms. Concrete examples of the heteroaryl group include pyridyl, imidazolyl, thiazolyl, furyl, benzofuryl, thienyl, benzothienyl, and the like . When R¹ and R² or R² and R³ are taken together with each other to form a ring, such a ring may be a monocycle or polycycle, with a five- or six-membered ring being preferred. Specific examples of the formed rings are cyclopentane, cyclohexane, and the like.

The preferred example of the trivalent hexadentate ortho-metallated iridium complexs represented by the formula (III) includes those representedby the following formula (XII)

(wherein R⁸, R⁹, R¹⁰, R¹¹, R¹, R², R³, and the ring B each has the same meanings as mentioned above; and the ring B may be taken with the pyridyl group binding to the ring B to form a ring)

Specific examples of the trivalent hexadentate ortho-metallated iridium complexes represented by the formula

(III) include the following compounds (Ill-i) to (III-xvi) .

(Hl-vi)

(IIHx) (III-x)

(III-xiii)

In the trivalent hexadentate ortho-metallated iridium complexes represented by the formula (IV) :

(wherein the rings B and C each has the same meanings as mentioned above; the ring D represents an optionally substituted pyridyl group; and the rings B and C may be taken with each other to form a fused ring) produced by the process of the present invention, the rings B and C each has the same meanings as in the formula (II) . The ring D contains a pyridine ring, which may be a monocyclic, polycyclic or condensed cyclic ring, in which one or two or more of the hydrogen atom ( s) may be substituted by a substituent or substituents. There is no limitation in the substituents as long as they have no adverse effect on the reaction in production of the trivalent hexadentate ortho-metallated iridium complex represented by the formula (IV) . Such substituents may be exemplified by those as mentioned about the substituted aryl and heteroaryl groups in the formula (II) . Specific examples of the trivalent hexadentate ortho-metallated iridium complexes represented by the formula

(IV) include the complexes represented by the following formula

(wherein R⁴, R⁵, R⁶, and R⁷ each represents independently a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group, alkylthio group, a cyano group, acyl group, alkyloxycarbonyl group, a nitro group, or halogen atom; R⁸, R⁹, R¹⁰, R^1:L,and the ring B each has the same meanings as mentioned above)

The alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group, alkylthio group, acyl group, and alkyloxycarbonyl group represented by R⁸, R⁹, R¹⁰, R¹¹, R⁴, R⁵, R⁶, and R⁷ in the formula (XIII) may be the same as mentioned above. These groups may have an additional substituent or substituents, which may be the same as those mentioned in the substituted aryl or heteroaryl groups in the formula (II) . The preferred ring B includes phenyl group, substituted phenyl group, naphthyl group, substitutednaphthyl group, furyl group, substituted furyl group, benzofuryl group, substituted benzofuryl group, thienyl group, substituted thienyl group, benzothienyl group, substituted benzothienyl group, and the like. The substituent on the substituted phenyl group, substituted naphthyl group, substituted furyl group, substituted benzofuryl group, substituted thienyl group, and substituted benzothienyl group may be exemplified by those mentioned in the substituted aryl group or heteroaryl group in the formula (II) .

Specific examples of the trivalent hexadentate ortho-metallated iridium complexes represented by the formula (IV) are the following compounds (IV-i) to (IV-viii).

(IV-v) (iV-vi)

In the trivalent hexadentate ortho-metallated iridium complexes represented by the formula (V) :

(wherein the rings B and C each has the same meanings as mentioned above) produced by the process of the present invention, the rings

B and C may be the same as mentioned above. The preferred trivalent hexadentate ortho-metallated iridium complexes of the formula (V) include those represented by the following formula (XIV) :

(wherein R⁸, R⁹, R¹⁰, R¹¹, and the ring B each has the same meanings as mentioned above; and the ring B may be taken with the pyridyl group binding to the ring B to form a ring).

The preferred ring B includes phenyl group, substituted phenyl group, naphthyl group, substituted naphthyl group, furyl group, substituted furyl group, benzofuryl group, substituted benzofuryl group, thienyl group, substituted thienyl group, benzothienyl group, substituted benzothienyl group, and the like. The substituent on the substituted phenyl group, substituted naphthyl group, substituted furyl group, substituted benzofuryl group, substituted thienyl group, and substituted benzothienyl group may be exemplified by those mentioned in the substituted aryl group or heteroaryl group in the formula (II) .

Specific examples of the trivalent hexadentate ortho-metallated iridium complexes represented by the formula (V) are the following compounds (V-i) to (V-x) .

(V-i) (V-ii) (V-iii) (V-iv)

The followings will explain the compounds represented by the formulae (VI) to (VIII) which are used as the starting compounds in the process of the present invention.

The coordination compound in the manufacturing process of the present invention means the compound having a chemical structure capable of forming a ligand of iridium complex. Such a compound includes a coordination compound which can entirely become a ligand for an iridium complex, or fromwhich the partial atom or atomic group may leave to form a ligand for an iridium complex.

In the compounds represented by the formula (VI ;

(wherein the rings B and C each has the same meanings as mentioned above) used in the process of the present invention, the rings B and C are the same as those described in the above-mentioned formula (II) . The preferred examples of the compounds represented by the formula (VI) include the compounds represented by the following formula (XV) :

(wherein R⁸, R⁹, R , and R each represents independently a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group, alkylthio group, a cyano group, acyl group, alkyloxycarbonyl group, a nitro group, or halogen atom; the ring B represents an optionally substituted aryl or heteroaryl group; or the ring B may be taken with the pyridyl group binding to the ring B to form a ring)

The alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group, alkylthio group, acyl group, and alkyloxycarbonyl group represented by R⁸, R⁹, R¹⁰, and R¹¹ in the formula (XV) may have an additional substituent or substituents, which may be exemplified by those mentioned in the substituted aryl or heteroaryl groups in the formula (II) .

The preferred ring B includes phenyl group, substituted phenyl group, naphthyl group, substituted naphthyl group, furyl group, substituted furyl group, benzofuryl group, substituted benzofuryl group, thienyl group, substituted thienyl group, benzothienyl group, substituted benzothienyl group, and the like. The substitutent on the substitutedphenyl group, substituted naphthyl group, substituted furyl group, substituted benzofuryl group, substituted thienyl group, and substituted benzothienyl group may be exemplified by those mentioned in the substituted aryl group or heteroaryl group in the formula (II) .

Specific examples of the compound represented by the formula (VI) are following compounds (Vl-i) to (Vl-xxvii) .

(VI- i) (VI- ii) (VI — Hi) (VI- iv)

(Vl-vii) (Vl-viii) (Vl-ix) (VI-x)

(Vl-xiii) (Vl-xiv) (VI -xv)

(Vl-xvi) (Vl-xvii) (Vl-xviii) (Vl-xix) (VI-xx)

(Vl-xxii) (Vl-xxiii) (Vl-xxiv) (VI-xxv)

(Vl-xxvi) (VI— xxvii)

In the compounds represented by the formula (VII)

(wherein R¹, R² and R³ each have the same meanings as mentioned above) used in the process of the invention, the alkyl group, alkoxy group, aryl group and heteroaryl group may have an additional susbstituent or substituents, which may be the same as those described in the formula (III). Moreover, the groups represented by R¹, R² and R³ in the compound represented by the formula (VII) are also the same as described in the formula (III) .

The compounds represented by the formula (VII) used in the invention are specifically exemplified by acetylacetone, 2-acetylcyclohexanone, 2-trifluoroacetylcyclopentanone, 1, 3-diphenyl-l, 3-propanedione, 2,2, 6, 6-tetramethyl-3, 5-heptanedione, 3-methyl-2, 4-pentanedione, 1, 1, 1, 5, 5, 5-hexafluoro-2, 4-pentanedione,

1-phenyl-l, 3-butanedione, 1-furyl-l, 3-butanedione and the like .

In the compounds represented by the formula (VIII) :

(wherein the ring D has the same meanings as mentioned above) used in the process of the invention, the ring D has the same meanings as mentioned in the formula (IV) . The preferred examples of the compounds represented by the formula (VIII) include pyridinecarboxylic acids or derivatives thereof represented by the following formula (XVI) :

(wherein R , R , R , and R each represents independently a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group, alkylthio group, a cyano group, acyl group, alkyloxycarbonyl group, a nitro group, or halogen atom)

In R⁴, R⁵, R⁶, and R⁷ in the formula (XVI) , the alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group, alkylthio group, acyl group, and alkyloxycarbonyl group are the same as described above. These groups may have an additional substituent or substituents, which may be the same as mentioned in the substituted aryl and heteroaryl groups in the formula (II) .

Specific examples of the compound represented by the formula (VIII) are following compounds (VHI-i) to (VHI-vii) .

(VIII -i) (VIII -ii) (VHI-iii) (VIII -iv)

(VIII-v) (VIII -vi) (VHI-vii)

The processes in the present invention will be explained in the following items 1) to 4) according to the reaction schemes 1 to 4.

1) Scheme 1 illustrated the reaction formula of aprocess for producing a trivalent hexadentate ortho-metallated iridium dinuclear complex of the formula (II) from a monovalent iridium dinuclear complex of the formula (I) as a starting compound. [Scheme 1]

Formula (I) 2

The trivalent hexadentate ortho-metallated iridium dinuclear complex represented by the formula (II) may readily be produced by reacting a monovalent iridium dinuclear complex of the formula (I) with a compound of the formula (VI) in or without a suitable solvent if required under an atmosphere of inert gas.

As an amount of the monovalent iridium dinuclear complex represented by the formula (I) and the compound represented by the formula (VI) , the compound represented by the formula

(VI) may be used usually in the amount appropriately selected from the range of 2 to 50 equivalents, preferably 3 to 20 equivalents, morepreferably 4 to 6 equivalents to themonovalent iridium dinuclear complex of the compound represented by the formula (I) .

The process of the present invention is preferably carried out in the presence of the solvent. In this process, it is appropriate to use a solvent, for example, an amide such as N,N-dimethylformamide, formamide, or N,N-dimethylacetamide; a cyano-containing organic compound such as acetonitrile; a halogenated hydrocarbon such as dichloromethane, 1, 2-dichloroethane, chloroform, carbon tetrachloride, or o-dichlorobenzene; an aliphatic hydrocarbon such as pentane, hexane, heptane, octane, or decane; an aromatic hydrocarbon such as benzene, toluene, or xylene; an ether such as diethyl ether, diisopropyl ether, tert-butyl methyl ether, di- methoxyethane, tetrahydrofuran, 1,4-dioxane, or 1, 3-dioxolane; a ketone such as acetone or methyl ethyl ketone; an alcohol such as methanol, ethanol, 2-propanol, n-butanol, tert-butanol, or 2-ethoxyethanol; a polyhydric alcohol such as ethylene glycol, propylene glycol, 1, 2-propanediol, or glycerin; or water. These solvents may be used alone or in combination of two or more members. Among these solvents, it is preferred to use an alcohol such as methanol, ethanol, 2-propanol, n-butanol, tert-butanol, or 2-ethoxyethanol; a polyhydric alcohol such as ethylene glycol, propylene glycol, 1, 2-propanediol, or glycerin; andwater, alone or in combination of two or more members.

There is no limitation in the amount of the solvent to be used as long as it promotes the reaction satisfactorily, and it may be used usually in the amount of 1 to 200 parts, preferably about 5 to 50 parts for 1 part of the monovalent iridium dinuclear complex represented by the formula (I).

In the above process, the reaction is preferably carried out in an atmosphere of an inert gas. As the inert gas, for example, nitrogen gas, argon gas, or the like can be used. The reaction may also be carried out in combination with an ultrasonic generator.

The reaction temperature is selected usually from the range of 25°C to 300°C, preferably from 60°C to 200°C, and more preferably from 80°C to 150°C.

The reaction time is selected usually from the range of 10 minutes to 72 hours, preferably 30 minutes to 48 hours, more preferably 1 to 6 hours.

Thus resulting product is preferably used in the succeeding reaction without any post-treatment, but if necessary it may be carried out, post-treatment isolation and purification. The post-treatmentmaybe conducted, for example, by extraction with the reaction product, filtration of the precipitate, crystallization with addition of a solvent, evaporation of the solvent, and so on. These operations may be conducted alone or in combination. The purification is achieved, for example, by column chromatography, recrys- tallization, sublimation, and so on, which may be conducted alone or in combination.

2) Scheme 2 illustrated the reaction formula of aprocess for producing a trivalent hexadentate ortho-metallated iridium complex represented by the formula (III) from a monovalent iridium dinuclear complex of the formula (I) as a starting compound.

Formula (III)

First, according to the process illustrated in Scheme 1, the trivalent hexadentate ortho-metallated iridium dinuclear complex represented by the formula (II) may readily be produced by reacting a monovalent iridium dinuclear complex represented by the formula (I) with a compound represented by the formula (VI) in or without a suitable solvent if required under an atmosphere of inert gas.

Subsequently, the resulting trivalent hexadentate ortho-metallated iridium dinuclear complex represented by the formula (II) is allowed to react with a compound of the formula (VII ) inorwithout a suitable solvent if required in the presence of a base and if required under an atmosphere of inert gas to smoothly give the trivalent hexadentate ortho-metallated iridium dinuclear complex represented by the formula (III) .

In this step, the trivalent hexadentate ortho-metallated iridiumdinuclear complex representedby the formula (II), after carried out the post-treatment, isolation and purification as mentioned above, may be allowed to react with a compound represented by the formula (VII) . In this process, however, it is appropriate without any post-treatment and the like of the trivalent hexadentate ortho-metallated iridium dinuclear complex to successively carry out the reaction of the complex represented by the formula (II) with a compound represented by the formula (VII) in one vessel (i.e., one-pot reaction) .

The compound represented by the formula (VII) and a base may be added separately into the reaction medium, or alternatively the compound of the formula (VII) may previously be allowed to react with a base and then added to the reaction medium. When the compound represented by the formula (VII) is first allowed to react with a base as mentioned below, for example, sodium acetylaceonate, potassium 2-acetylcyclohexanate, potassium benzoylacetonate, etc., may be used as a derivative from the compound of the formula (VII) .

As an amount of the monovalent iridium dinuclear complex represented by the formula (I) and the compound represented by the formula (VI), the compound represented by the formula (VI) may be used usually in the amount appropriately selected froma range of 2 to 50 equivalents, preferably 3 to 20 equivalents, and more preferably 4 to 6 equivalents to the monovalent iridium dinuclear complex represented by the formula (I) .

As amount of the compound representedby the formula (VII) may be used usually in the amount of 1 to 20 equivalents, preferably 1.5 to 10 equivalents, and more preferably 2 to 3 equivalents to the monovalent iridium dinuclear complex represented by the formula (I) .

In this process, the reaction is preferably carried out in the presence of a base. As the base, an inorganic base and organic base are exemplified. The inorganic base includes sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, and metal hydrides such as sodium hydride and the like. The organic base includes alkali metal alkoxides such as potassium methoxide, sodium methoxide, lithium methoxide, sodium ethoxide, and potassium tert-butoxide; and organic amines such as triethylamine, diisopropylethylamine, N,N-dimethylaniline, piperidine, pyridine, 4-dimethylaminopyridine,

1, 5-diazabicyclo [4.3.0] non-5-ene,

1, 8-diazabicyclo [5.4.0]undec-7-ene, tri-n-butylamine, and N-methylmorpholine .

An amount of the base may be used usually in the amount appropriately selected from a range of 0.5 to 10 equivalents, preferably 0.8 to 2 equivalents, and more preferably 1 to 1.2 equivalents to the compound of the formula (VII).

In this process, the reaction is preferably carried out in an atmosphere of inert gas such as nitrogen gas or argon gas. Also, this process may be carried out using an ultrasonic generator.

In this process, it is appropriate to use a solvent. As for the solvent, those as exemplified in Scheme 1 can be used.

The reaction time is selected usually from the range of 3 minutes to 48 hours, preferably 10 minutes to 24 hours, more preferably 30 minutes to 3 hours.

Thus resulting trivalent hexadentate ortho-metallated iridium complex represented by the formula (III) is then subjected to post-treatment, isolation and purification as mentioned in Scheme 1 to provide a phosphorescent material.

3) Scheme 3 illustrated the reaction sequence of a process for producing a trivalent hexadentate ortho-metallated iridiumcomplex representedbythe formula (IV) fromamonovalent iridium dinuclear complex represented by the formula (I) as a starting compound.

First, according to the process illustrated in Scheme

1, the trivalent hexadentate ortho-metallated iridium dinuclear complex represented by the formula (II) may readily be produced by reacting a monovalent iridium dinuclear complex represented by the formula (I) with a compound of the formula (VI) in or without a suitable solvent if required under an atmosphere of inert gas.

Subsequently, the resulting trivalent hexadentate ortho-metallated iridium dinuclear complex represented by the formula (II) is allowed to react with a compound represented by the formula (VIII) in or without a suitable solvent if required in the presence of a base, if required under an atmosphere of inert gas to smoothly give the trivalent hexadentate ortho-metallated iridium complex of the formula (IV).

In this step, the trivalent hexadentate ortho-metallated iridium dinuclear complex of the formula (II) , after carried out the post-treatmnet, isolation andpurification as mentioned above, may be allowed to react with a compound represented by the formula (VIII) . In this process, however, it is appropriate without any post-treatment of the trivalent hexadentate ortho-metallated iridium dinuclear complex to successively carry out the reaction of the complex of the formula (II) with a compound of the formula (VIII) in one vessel (i.e., one-pot reaction) .

The compound represented by the formula (VIII) and the base may be added separately into the reaction medium, or alternatively the compound of the formula (VIII) may previously be allowed to react with the base and then added to the reaction medium. When the compound of the formula (VIII) is first allowed to react with the base as mentioned below, for example, sodium picolinate, sodium 3-cyanopyridine-2-carboxylate, potassium 5-phenylpyridine-2-carboxylate, etc., may be used as a derivative from the compound of the formula (VIII) .

As an amount of the monovalent iridium dinuclear complex represented by the formula (I) and the compound represented by the formula (VI), the compound represented by the formula (VI) may be used usually in the amount appropriately selected froma range of 2 to 50 equivalents, preferably 3 to 20 equivalents, andmore preferably 4 to 6 equivalents to the monovalent iridium dinuclear complex represented by the formula (I).

The compound of the formula (VIII) may be used usually in the amount of 1 to 20 equivalents, preferably 1.5 to 10 equivalents, and more preferably 2 to 3 equivalents to the monovalent iridium dinuclear complex of the formula (I) .

In this process, the reaction is preferably carried out in the presence of a base. As the base, those as exemplified in Scheme 2 may be used.

In this process, the reaction is preferably carried out in an atmosphere of inert gas such as nitrogen gas, argon gas, and so on. The reaction may also be carried out in combination with an ultrasonic generator.

Thus resulting trivalent hexadentate ortho-metallated iridiumcomplex representedby the formula (IV) is then subjected to post-treatment, isolation and purification as mentioned in Scheme 1 to provide a phosphorescent material.

4) Scheme 4 illustrates the reaction formula of aprocess for producing a trivalent hexadentate ortho-metallated iridium dinuclear complex represented by the formula (V) from a monovalent iridiumdinuclear complex representedby the formula

(I) as a starting compound.

[Scheme 4]

Formula (VI)

Formula (I)

Silver salt Formula (VI)

Formula (V)

First, according to the process illustrated in Scheme

Subsequently, the resulting trivalent hexadentate ortho-metallated iridium dinuclear complex of the formula (II) is allowed to react with a compound of the formula (VI) and a silver salt in or without a suitable solvent if required under an atmosphere of inert gas to smoothly give the trivalent hexadentate ortho-metallated iridium complex of the formula (V) .

In this step, the trivalent hexadentate ortho-metallated iridium dinuclear complex of the formula (II), after carried out the post-treatment, isolation andpurification as mentioned above, may be allowed to react with a silver salt and a compound of the formula (VI) . In this process, however, it is appropriate without any post-treatment and the like of the trivalent hexadentate ortho-metallated iridium dinuclear complex to carry out the reaction of the complex represented by the formula (II) with the silver salt successively added to the reaction vessel (i.e., one pot reaction).

Alternatively, the compound represented by the formula (I) is first allowed to react with a compound represented by the formula (VI), to which a silver salt is then added, and then the compound of the formula (VI) is added to continue the reaction.

The silver salt includes, for example, silver nitrate, silver acetate, silver trifluoroacetate, silver methane- sulfonate, silver trifluoromethanesulfonate, and the like, with silver trifluoroacetate or silver trifluoromethanesulfonate being preferred.

The silver salt may be used usually in the amount of 1 to 20 equivalents, preferably 1.5 to 10 equivalents, and more preferably 2 to 3 equivalents to the compound represented by the formula (I) .

In this reaction, the compound represented by the formula

(VI) may be used usually in the amount appropriately selected from a range of 4 to 100 equivalents, preferably 6 to 40 equivalents, and more preferably 8 to 12 equivalents to the monovalent iridium dinuclear complex representedby the formula

(I) . In addition, when the compound representedby the formula

(VI) is further added after the addition of the silver salt, the compound of the formula (VI) may be added usually in the amount appropriately selected from a range of 2 to 50 equivalents, preferably 3 to 10 equivalents, and more preferably 4 to 6 equivalents to the compound represented by the formula (I) .

In this process, it is appropriate to use a solvent. As for the solvent, those as exemplified in Scheme 1 can be used. The reaction temperature is selected usually from the range of 25°C to 300°C, preferably from 60°C to 200°C, and more preferably from 80°C to 150°C. The reaction time is selected usually from the range of 10 minutes to 72 hours, preferably 30 minutes to 48 hours, more preferably 1 hour to 6 hours.

Thus resulting trivalent hexadentate ortho-metallated iridium complex of the formula (V) is then subjected to post-treatment, isolation and purification as mentioned in Scheme 1 to provide a phosphorescent material.

The process of the present invention is characterized in that the monovalent iridium dinuclear complexes are used. Thus, the trivalent hexadentate ortho-metallated iridium complexes representedby the formula (II), (III), (IV) or (V) can be produced in high efficiency, and in addition it becomes possible to produce them in one-pot process without isolating the intermediate trivalent hexadentate ortho-metallated iridium dinuclear complexes of the formula (II) . The process of the present invention is characterized by the followings.

1) The multi-step reaction can be carried out in the same reaction vessel and in the same solvent.

2) No complicated operations are required, which operations are usually conducted after the synthesis of intermediates such as recovery of solvent, post-treatment, isolation and purification.

3) The physical loss of the intermediates caused by the operations as mentioned in the item 2) can be minimized.

4) The costs of the intermediates and the final products can be reduced for the reason 1) to 3) .

The trivalent hexadentate ortho-metallated iridium complexes produced by the processes of the invention are useful as phosphorescent materials.

EXAMPLES

The invention will be specifically explained by the following examples which are not intended as a limitation thereof.

In the respective Examples, s/s indicates the volume ratio of the solvent to the weight of the starting monovalent iridium dinuclear complex in the unit of mL/g.

Example 1 Production of Compound (Il-i)

(Bis (2-phenylpyridinato-N, C²' ) iridium (III) chloride dimer)

In a Schlenk' s flask equipped with a reflux condenser was placed (1, 5-cyclooctadiene) iridium(I) chloride dimer (2.00 g, 2.98 mmol, 1 equivalent) and the interior of the flask was substituted with nitrogen. There were successively added 2-ethoxyethanol (20 mL, s/s^lO) and 2-phenylpyridine (2.56 mL, 17.88 mmol, 6.0 equivalents), and the mixture was stirred in a nitrogen atmosphere under refluxing (135°C) . Immediately after the additionof the ligand (2-phenylpyridine) , the reddish suspension turned into ocher and then into a reddish solution as the dissolution of the ligand by heating, which gave an yellow suspension with stirring. After stirring for 3 hours, the solvent was distilledoff fromthe reactionmixture under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: dichloromethane/methanol = 10/1). The column fractions were condensed, and the resulting yellow solid material was recrystallized from hexane/dichloromethane to give 3.06 g of the title compound (Il-i) as yellow powder in 95.8% yield.

^XE NMR (500MHz, CD₂C1₂) : δ

5.87 (dd, J=l.l, 7.8Hz, 4H) , 6.60 (dt, J=1.2, 7.8Hz, 4H) , 6.79-6.85 (m, 8H) , 7.56 (dd, J=1.3, 7.8Hz, 4H) , 7.80 (dt, J=1.6, 7.8Hz, 4H) , 7.94 (d, J=7.8Hz, 4H) , 1.25 (dd, J=0.8, 5.7Hz, 4H) .

Example 2 Production of Compound (2-10) (Bis [2- (2, 4-difluorophenyl) pyridinato-N,C²' ] iridium (III) chloride dimer)

In a Schlenk' s flask equipped with a reflux condenser was placed (1, 5-cyclooctadiene) iridium (I) chloride dimer (2.00 g, 2.98 mmol, 1 equivalent) and the interior of the flask was substituted with nitrogen. There were successively added 2-ethoxyethanol (20 mL, s/s=10) and 2- (2, 4-difluorophenyl) pyridine (3.42 g, 17.88 mmol, 6.0 equivalents) , and the mixture was stirred in a nitrogen atmosphere under refluxing (135°C) . Immediately after the addition of the ligand (2- (2, 4-difluorophenyl) pyridine), the reddish suspension turned into gray and then into a dark reddish solution as the dissolution of the ligand by heating, which gave an lemon yellow suspension with stirring. After stirring for 3 hours, the solvent was distilled off from the reactionmixture under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: dichloromethane/methanol = 10/1) . The column fractions were condensed, and the resulting yellow green solid material was recrystallized from hex- ane/dichloromethane to give 3.53 g of the title compound (2-10 ) as yellow green powder in 97.4% yield.

^XH NMR(500MHz CD₂C1₂) : δ

5.29 (dd, J=2.5, 9.1Hz, 4H) , 6.38 (ddd, J=2.5, 9.1, 12.5Hz, 4H),

6.87 (ddd, J=1.5, 5.8, 7.2Hz, 4H) , 7.87(ddd, J=1.5, 5.8, 7.2Hz, 4H) , 8.33 (ddd, J=0.7, 1.5, 8.1Hz, 4H) , 9.12 (ddd, J=0.7, 1.5, 5.8Hz, 4H) .

Example 3 Production of Compound (2-9) (Bis [2- (4-methylphenyl) pyridinato-N, C²' ] iridium (III) chloride dimer)

In a Schlenk' s flask equipped with a reflux condenser was placed (1, 5-cyclooctadiene) iridium (I) chloride dimer (500 mg, 0.744 mmol, 1 equivalent) and the interior of the flask was substituted with nitrogen. There were successively added

2-ethoxyethanol (5 L, s/s=10) and 2- (4-methylphenyl) pyridine

(504 mg, 2.976 mmol, 4.0 equivalents), and the mixture was stirred in a nitrogen atmosphere under refluxing (135°C) . Immediately after the addition of the ligand (2- (4-methylphenyl ) pyridine) , the reddish suspension turned into ocher and then into a dark reddish solution as the dissolution of the ligand by heating, which gave yellow precipitate with stirring. After stirring for 3 hours, the solventwas distilledoff fromthe reactionmixtureunder reduced pressure, and the residue was purified by silica gel column chromatography (eluent: dichloromethane/methanol = 100/1 to 20/1) . The column fractions were condensed, and the resulting yellow solidmaterial was recrystallized fromhexane/dichloro- methane to give 734 mg of the title compound (2-9) as yellow powder. From the crystallization mother liquid, an additional 60 mg of a recrystallized product was obtained in the same shape. Total yield: 794 mg (94.6%).

^XH NMR(500MHz, CD₂C1₂) : δ

1.96 (s, 12H) , 5.66 (d, J=0.7Hz, 4H) , 6.61-6.64 (m, 4H) , 6.77 (ddd, J=1.5, 5.7, 7.4Hz, 4H) , 7.44 (d, J=7.8Hz, 4H) , 7.75 (ddd, J=1.5, 7.4, 8.1Hz, 4H) , 7.87 (ddd, J=0.7, 1.5, 8.1Hz, 4H) , 9.19 (ddd, J=0.7, 1.5, 5.7Hz, 4H) . Example 4 Production of Compound (2-12)

(Bis [2- (4-methoxyphenyl) -5-trifluoromethylpyridinato-N, C²' ] iridium (III) chloride dimer)

In a Schlenk' s flask equipped with a reflux condenser wereplaced (1, 5-cyclooctadiene) iridium (I) chloride dimer (200 mg, 0.298 mmol, 1 equivalent) and 2- (4-methoxyphenyl) -5-trifluoromethylpyridine (302 mg, 1.192 mmol, 4.0 equivalents), and the interior of the flask was substituted with nitrogen. There was added 2-ethoxyethanol

(5 mL, s/s=10) , and the mixture was stirred in a nitrogen atmosphere under refluxing (135°C) . The reddish suspension obtained after addition of the ligand

(2- (4-methoxyphenyl) -5-trifluoromethylpyridine) was dissolved by heating and gave bright yellow precipitate with stirring. After stirring for 3 hours, the solvent was distilled off from the reaction mixture under reduced pressure, and the residue was purified by silica gel column chromatography

(eluent: dichloromethane/methanol = 100/0 to 100/1). The column fractions were condensed, and the resulting orange solid material was recrystallized from hexane/dichloromethane to give 394 mg of the title compound (2-12) as bright yellow powder in 90.3% yield. ^λE NMR(500MHz_N CD₂C1₂) : δ 3.40 (s, 12H) , 5.22 (d, J=2.5Hz, 4H) ,

6.49 (dd, J=2.5, 8.6Hz, 4H) , 7.58 (d, J=8.6Hz, 4H) ,

7.90-7.95 (m, 8H) , 9.57 (s, 4H) .

Example 5 Production of Compound (Ill-i) (Bis (2-phenylpyridinato-N, C²' ) iridium(III) acetylacetonate)

(1) In a Schlenk' s flask equippedwith a reflux condenser was placed (1, 5-cyclooctadiene) iridium (I) chloride dimer (500 mg, 0.744 mmol, 1 equivalent) and the interior of the flask was substituted with nitrogen. There were successively added

2-ethoxyethanol (5 mL, s/s=10) and 2-phenylpyridine (468 μL, 3.274 mmol, 4.4 equivalents), and the mixture was stirred in a nitrogen atmosphere under refluxing (135°C) for 3 hours. The resulting yellow suspension was cooled to room temperature, to which were added acetylacetone (230 μL, 2.232 mmol, 3.0 equivalents) and sodium carbonate (237 mg, 2.232 mmol, 3.0 equivalents) successively, and further stirred under refluxing for 2 hours to give a bright yellow suspension. The solvent was distilled off from the reaction mixture under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: dichloromethane). The column fractions were condensed, and recrystallized from hexane/dichloromethane to give 720 mg of the title compound (Ill-i) as bright yellow powder in 80.7% yield. ^XH NMR(500MHz CD₂Cl₂) : δ

1.79 (s, 6H) , 5.23 (s, IH) , 6.23 (dd, J=1.2, 7.3Hz, 2H) ,

6.68 (dt, J=1.3, 7.3Hz, 2H) , 6.84 (ddd, J=1.2, 7.3, 7.7Hz, 2H),

7.19 (ddd, J=1.6, 5.7, 7.5Hz, 2H) , 7.57 (dd, J=1.3, 7.7Hz, 2H),

7.77 (ddd, J=1.6, 7.5, 8.2Hz, 2H) ,

7.88 (ddd, J=0.8, 1.6, 8.2Hz, 2H) ,

8.49 (ddd, J=0.8, 1.6, 5.7Hz, 2H) .

(2) The same operation was made in a large scale. The reaction was carried out using (1, 5-cyclooctadiene) iridium (I) chloride dimer (5.00 g, 7.44 mmol, 1.0 equivalent), 2-phenylpyridine (4.7 mL, 32.74 mmol, 4.4 equivalents), acetylacetone (2.3 mL, 22.32 mmol, 3.0 equivalents), sodium carbonate (2.37 g, 22.32 mmol, 3.0 equivalents) and 2-ethoxyethanol (50 mL, s/s=10) as starting materials to give 8.03 g of the title compound (Ill-i) in 90.0% yield. The shape, physical properties and spectrum data of the product were identical with those of the product in Example 5 (1) . Since the yieldwas 80.7% inExample 5 (1), the process of the invention was recognized to be suitable for large-scale production.

Example 6 Production of Compound (3-10) (Bis [2- (2, 4-difluorophenyl) pyridinato-N, C²' ] iridium (III) acetylacetonate)

(1) In a Schlenk' s flask equippedwith a reflux condenser was placed (1, 5-cyclooctadiene) iridium(I) chloride dimer (500 mg, 0.744 mmol, 1 equivalent) and the interior of the flask was substituted with nitrogen. There were successively added 2-ethoxyethanol (5 L, s/s = 10) and 2- (2, 4-difluorophenyl) pyridine (626 mg, 3.274 mmol, 4.4 equivalents), and the mixture was stirred in a nitrogen atmosphere under refluxing (135°C) for 3 hours. The resulting lemon yellow suspension was cooled to room temperature, to which were added acetylacetone (230 μL, 2.232 mmol, 3.0 equivalents) and sodium carbonate (237 mg, 2.232 mmol, 3.0 equivalents) successively, and further stirred under refluxing for 2 hours to give an yellow suspension. The solvent was distilled off fromthe reactionmixture under reducedpressure, andthe residue was purified by silica gel column chromatography (eluent: dichloromethane) . The column fractions were condensed, and recrystallized from hexane/dichloromethane to give 896 mg of the title compound (3-10) as lemon yellow powder in 78.9%.

^XE NMR(500MHz CD₂C1₂) : δ

1.80 (s, 6H) , 5.31 (s, IH) , 5.50 (dd, J=2.4, 8.8Hz, 2H) ,

6.38 (ddd, J=2.4, 9.3, 12.5Hz, 2H) ,

7.24 (ddd, J=1.5, 5.7, 7.3Hz, 2H) ,

7.84 (ddt, J=0.6, 1.6, 7.3Hz, 2H) , 8.22-8.28 (m, 2H) ,

8.44 (ddd, J=0.8, 1.6, 5.7Hz, 2H) . (2) The same operation was made in a large scale. The reaction was carried out using (1, 5-cyclooctadiene) iridium(I) chloride dimer (5.00 g, 7.44 mmol, 1.0 equivalent), 2- (2, -difluorophenyl) pyridine (6.00 g, 32.74 mmol, 4.2 equivalents), acetylacetone (2.3 mL, 22.32 mmol, 3.0 equivalents), sodium carbonate (2.37 g, 22.32 mmol, 3.0 equivalents) and 2-ethoxyethanol (50 mL, s/s=10) as starting materials to give the title compound (3-10) as 8.53 g of lemon yellow powder as the first crop and 0.57 g of yellow powder as the second crop fraction in 95.9% purity. Total yield was 90.5%. The shape, physical properties and spectrum data of the product was identical with those of the product in Example 6 (1) .

Since the yield was 78.9% in Example 6 (1), the process of the invention was recognized to be suitable for large-scale production.

Example 7 Production of Compound (3-9) (Bis [2- (4-methylphenyl) pyridinato-N, C²' ] iridium (III) acetylacetonate)

In a Schlenk' s flask equipped with a reflux condenser was placed (1, 5-cyclooctadiene) iridium (I) chloride dimer (500 mg, 0.744 mmol, 1 equivalent) and the interior of the flask was substituted with nitrogen. There were successively added 2-ethoxyethanol (5mL, s/s=10) and 2- (4-methylphenyl) pyridine (504 mg, 2.976 mmol, 4.0 equivalents), and the mixture was stirred in a nitrogen atmosphere (135°C) for 3 hours. The resulting yellow suspension was cooled to room temperature, to which were added acetylacetone (230 μL, 2.232 mmol, 3.0 equivalents) and sodium carbonate (237 mg, 2.232 mmol, 3.0 equivalents) successively, and further stirred for 3 hours to give an ocher suspension. The solvent was distilled off from the reaction mixture under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: dichloromethane) . The column fractions were condensed, the resulting yellow solid was and recrystallized from hexane/dichloromethane to give 736 mg of the title compound (3-9) as yellow powder. An additional crop of the recrystallized crystals (27 mg) was obtained in the same shape from the crystallization mother liquid. Total yield: 763 mg (81.7%) . ^λE NMR(500MHz CD₂C1₂) : δ 1.78 (s, 6H) , 2.06 (s, 6H) , 5.26 (s, IH) , 6.04 (s, 2H) , 6.67 (d, J=7.9Hz, 2H) , 7.14 (ddd, J=1.6, 5.8, 7.2Hz, 2H) , 7.46 (d, J=7.9Hz, 2H) , 7.74 (ddd, J=1.6, 7.2, 8.3Hz, 2H) , 7.82 (ddd, J=0.8, 1.6, 8.3Hz, 2H) , 8.45 (ddd, J=0.8, 1.6, 5.8Hz, 2H) ,

Example 8 Production of Compound (3-11) (Bis [2- (4-methoxyphenyl) -5-trifluoromethylpyridinato-N, C²'] iridium (III) acetylacetonate)

In a Schlenk' s flask equipped with a reflux condenser wereplaced (1, 5-cyclooctadiene) iridium (I) chloride dimer (500 mg, 0.744 mmol, 1 equivalent) and

2- (4-methoxyphenyl) -5-trifluoromethylpyridine (754 mg, 2.976 mmol, 4.0 equivalents), and the interior of the flask was substituted with nitrogen. There was added 2-ethoxyethanol (5 mL, s/s=10) , and the mixture was stirred in a nitrogen atmosphere under refluxing (135°C) for 3 hours . The resulting blight yellow suspension was cooled to room temperature, to which were added acetylacetone (230 μL, 2.232 mmol, 3.0 equivalents) and sodium carbonate (237 mg, 2.232 mmol, 3.0 equivalents) successively, and further stirred for 3 hours to give an orange suspension. The solvent was distilled off from the reaction mixture under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: dichloromethane) . The column fractions were condensed, and the resulting orange solid was recrystallized from hexane/ dichloromethane to give 920 mg of the title compound (3-11) as orange powder. A additional crop of the recrystallized crystals (60 mg) was obtained in the same shape from the crystallization mother liquid. Total yield: 980 mg (82.8%) .

^XH NMR(500MHz, CD₂Cl₂) : δ 1.82 (s, 6H) , 3.54 (s, 6H) , 5.33 (s, IH) , 5.71 (d, J=2.5Hz, 2H),

6.51 (dd, J=2.5, 8.7Hz, 2H) , 7.60 (d, J=8.7Hz, 2H) ,

7.85 (d, J=8.8Hz, 2H) , 7.91 (dd, J=2.2, 8.8Hz, 2H) ,

8.67 (d, J=2.2Hz, 2H) .

Example 9 Production of Compound (3-7) (Bis [2- (2' -benzothienyl) pyridinato-N, C³' ] iridium (III) acetylacetonate)

(1) In a Schlenk' s flask equippedwith a reflux condenser wereplaced (1, 5-cyclooctadiene) iridium (I) chloride dimer (500 mg, 0.744 mmol, 1 equivalent) and 2- (2' -benzothienyl) pyridine (629 mg, 2.976 mmol, 4.0 equivalents) , and the interior of the flask was substituted with nitrogen. There was added 2-ethoxyethanol (5 mL, s/s=10) , and the mixture was stirred in a nitrogen atmosphere under refluxing (135°C) . A solvent was added, and the resulting reddish suspension was heated to turn into a dark red solution, which gave reddish brown precipitate with stirring. The resulting vermilion suspension was cooled to roomtemperature, to whichwere addedacetylacetone

(230 μL, 2.232 mmol, 3.0 equivalents ) and sodium carbonate (237 mg, 2.232 mmol, 3.0 equivalents) successively, and further stirred under refluxing for 3 hours . The solvent was distilled off from the reaction mixture under reduced pressure, and the residue was purified by silica gel column chromatography

(eluent: dichloromethane). The column fractions were con- densed, and the resulting reddishbrown solidwas recrystallized from hexane/dichloromethane to give 743 mg of the title compound (3-7) as reddish brown powder in 70.1% yield.

¹H NMR(500MHz, CD₂C1₂) : δ 1.81 (s, 6H) , 5.35 (s, IH) , 6.18 (d, J=8.2Hz, 2H) , 6.83 (ddd, J=l.l, 7.2, 8.2Hz, 2H) , 7.05-7.11 ( , 4H) , 7.62-7.68 (m, 4H) , 7.82 (ddd, J=1.5, 7.5, 8.1Hz, 2H) , 8.45 (ddd, J=0.8, 1.5, 5.7Hz, 2H) .

(2) The same operation was made in a large scale. The reaction was carried out using (1, 5-cyclooctadiene) iridium (I ) chloride dimer (3.29 g, 4.90 mmol, 1.0 equivalent), 2- (2' -benzothienyl) pyridine (4.35 g, 20.59 mmol, 4.2 equivalents), acetylacetone (1.5 mL, 14.70 mmol, 3.0 equivalents), sodium carbonate (1.56 g, 14.70 mmol, 3.0 equivalents) and 2-ethoxyethanol (33 mL, s/s=10) as starting materials to give the title compound (3-7) as 5.23 g of reddish brown powder as the first crop and additional 0.17 g of reddish brown powder as the second crop. Total yield was 77.4%. The shape, physical properties and spectrum data of the product was identical with those of the product in Example 9 (1) .

Since the yieldwas 70.1% in Example 9 (1), the process of the invention was recognized to be suitable for large-scale production. Example 10 Production of Compound (4-2) (Bis [2- (2, 4-difluorophenyl) pyridinato-N, C⁶'] iridium (III) picolinate)

In a Schlenk' s flask equipped with a reflux condenser was placed (1, 5-cyclooctadiene) iridium (I) chloride dimer (500 mg, 0.744 mmol, 1.0 equivalent) and the interior of the flask was substituted with nitrogen. There were successively added 2-ethoxyethanol (5 L, s/s=10) and 2- (2, 4-difluorophenyl) pyridine (626 mg, 3.274 mmol, 4.4 equivalents) , and the mixture was stirred in a nitrogen atmosphere under refluxing (135°C) for 3 hours. The resulting lemon yellow suspension was cooled to room temperature, to which was added sodium picolinate (324 mg, 2.232 mmol, 3.0 equivalents), and further stirred under refluxing for 3 hours. The suspension slowly turn into orange with proceeding of the reaction. The solvent was distilled off from the reaction mixture under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: dichloromethane/methanol = 20/1). The column fractions were condensed, and the resulting yellow solid was recrystallized from hexane/dichloromethane to give 967 mg of the title compound (4-2) as lemon yellow powder in 93.6% yield.

¹H NMR(500MHz, CD₂C1₂) : δ 5.62 (dd, J=2.4, 8.7Hz, IH) , 5.85 (dd, J=2.4, 8.7Hz, IH) , 6.44 (ddd, J=2.4, 9.2, 12.6Hz, IH) , 6.50 (ddd, J=2.4, 9.2, 12.6Hz, IH) , 7.02 (ddd, J=1.5, 5.9, 7.4Hz, IH) ,

7.21 (ddd, J=1.5, 5.9, 7.4Hz, IH) ,

7.40 (ddd, J=1.5, 5.4, 7.6Hz,lH),

7.46 (ddd, J=0.8, 1.6, 5.9Hz, IH) , 7.75-7.86 (m, 3H) , 7.94 (dt,

J=1.5, 7.6Hz, IH) , 8.20-8.28 (m, 2H) , 8.28-8.37 (m, IH) ,

8.69 (ddd, J=0.7, 1.6, 5.9Hz, IH) .

Example 11 Production of Compound (V-i) (tris (2-phenylpyridinato-N, C²' ) iridium (III) )

2-ethoxyethanol (5 mL, s/s=10) and 2-phenylpyridine (468 μL, 3.274 mmol, 4.4 equivalents), and the mixture was stirred in a nitrogen atmosphere under refluxing (135°C) for 3 hours. The resulting yellow suspension was cooled to room temperature, to which was added silver (I) trifluoromethanesulfonate (573 mg, 2.232 mmol, 3.0 equivalents), and further stirred at room temperature for 10 minutes to give a dark brown suspension. There was added an additional amount of 2-ethoxyethanol (7 mL, s/s=14) and then dropwise added 2-phenylpyridine (638 μL, 4.464 mmol, 6.0 equivalents), and the mixture was further stirred under refluxing for 3 hours to give an ocher suspension. The solvent was distilled off from the reactionmixture under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: dichloromethane) . The column fractions were condensed, and the resulting yellow solid was recrystallized from hexane/dichloromethane to give 837 mg of the title compound (V-i) as yellow powder in 85.9% yield. ^lE NMR(500MHz CD₂C1₂) : δ 6.72-6.81 (m, 6H) , 6.85-6.93 (m, 6H) ,

7.56 (ddd, J=0.8, 1.6, 5.5Hz, 3H) , 7.62-7.69 (m, 6H) , 7.89-7.94 (m, 3H) .

Example 12 Production of Compound (5-6) (tris [2- (2, 4-difluorophenyl) pyridinato-N, C⁶' ] iridium (III) )

In a Schlenk' s flask equipped with a reflux condenser was placed (1, 5-cyclooctadiene) iridium (I) chloride dimer (500 mg, 0.744 mmol, 1 equivalent) and the interior of the flask was substituted with nitrogen. There were successively added 2-ethoxyethanol (5 mL, s/s=10) and 2- (2, 4-difluorophenyl) pyridine (626mg, 3.274 mmol, 4.4 equivalents) , and the mixture was stirred in a nitrogen atmosphere under refluxing (135°C) for 3 hours. The resulting yellow green suspension was cooled to room temperature, to which was added silver (I) trifluo- romethanesulfonate (573 mg, 2.232 mmol, 3.0 equivalents) , and equivalents) , and further stirredunder reflexing for 10 minutes to give a darkbrown suspension, which yieldedbrownprecipitate . There was added an additional amount of 2-ethoxyethanol (8.5 mL, s/s=17) and then dropwise added 2- (2, 4-difluorophenyl) pyridine (853 mg, 4.464 mmol, 6.0 equivalents), and the mixture was further stirred under refluxing for 3 hours to give an ocher suspension. The solvent was distilled off from the reaction mixture under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: dichloromethane). The column fractions were condensed, and the resulting yellow green solid was recrystallized from hexane/dichloromethane to give 983 mg of the title compound (5-6) as yellow green powder in 86.6% yield.

^XK NMR(500MHz_s CD₂C1₂) : δ 6.23 (dd, J=2.5, 9.2Hz, 3H) , 6.41 (ddd, J=2.5, 9.2, 13.1Hz, 3H),

6.97 (ddd, J=1.3, 5.6, 7.2Hz, 3H) , 7.50 (ddd, J=0.8, 1.6, 5.6Hz, 3H) , 7.70-7.77 (m, 3H) , 8.28-8.34 (m, 3H) .

Example 13 Production of Compound (5-7) (tris [2- (4-methoxyphenyl) pyridinato-N, C²'] iridium (III) )

In a Schlenk' s flask equipped with a reflux condenser wereplaced (1, 5-cyclooctadiene) iridium(I) chloride dimer (200 mg, 0.298 mmol, 1 equivalent) and 2- (4-methoxyphenyl) pyridine (222 mg, 1.311 mmol, 4.4 equivalents), and the interior of the flask was substituted with nitrogen. There was added 2-ethoxyethanol (2 mL, s/s=10), and the mixture was stirred in a nitrogen atmosphere under refluxing (135°C) for 3 hours. The resulting yellow suspension was cooled to room temperature, to which was added silver (I) trifluoromethanesulfonate (230 mg, 0.894 mmol, 3.0 equivalents) , and stirred under refluxing for 10 minutes to give brown precipitate. There was added an additional amount of 2-ethoxyethanol (2 mL, s/s=10) and then added 2- (4-methoxyphenyl) pyridine (252 mg, 1.490 mmol, 5.0 equivalents), and the mixture was further stirred under refluxing for 3 hours. The solvent was distilled off from the reaction mixture under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: dichloromethane) . The column fractions were condensed, and the resulting lemon yellow solid was recrystallized from hexane/ dichloromethane to give 316 mg of the title compound (5-7) as lemon yellow powder in 76.1% yield.

^XH NMR(500MHz_N CD₂C1₂) : δ 3.55 (s, 9H) , 6.31 (d, J=2.7Hz, 3H) , 6.46 (dd, J=2,7, 8.6Hz, 3H),

6.83 (ddd, J=1.3, 5.6, 7.2Hz, 3H) , 7.58 (ddd, J=1.6, 7.2, 8.3Hz,3H), 7 . 60 ( d, J=8 . 6Hz , 3H) , 7 . 78 ( ddd, J=0 . 8 , 1 . 3 , 8 . 3Hz , 3H) .

Example 14 Two-step production of Compound (V-i)

(tris (2-phenylpyridinato-N, C²' ) iridium (III ) )

In a Schlenk' s flask were placed Compound (Il-i)

(Bis (2-phenylpyridinato-N, C²') iridium (III) chloride dimer) produced in Example 1 (200 mg, 0.187 mmol, 1 equivalent) and silver (I) trifluoromethanesulfonate (144 mg, 0.561 mmol, 3.0 equivalents), and the interior of the flask was substituted with nitrogen. There were added 2-ethoxyethanol (lmL, s/s=5) and 2-phenylpyridine (163 μL, 1.122 mmol, 6.0 equivalents), and the mixture was stirred under refluxing (135°C) for 3 hours . The resulting ocher suspension was condensed, and the residue was purified by silica gel column chromatography (eluent: dichloromethane) . The column fractions were condensed, and recrystallized from hexane/dichloromethane to give 208 mg of the title compound (V-i) as yellow powder in 83.4% yield. NMR data of the product was identical to that of Example 11.

Total yield from Example 1 was 79.9%. When this step was carried out in one vessel, the total yield in Example 11 was 85.9% (see Example 11) . This indicates that the process of the invention can beneficially be conducted in one vessel.

Comparative Example 1 Production of Compound (5-6) (tris [ 2- (2, 4-difluorophenyl) pyridinato-N, C⁶'] iridium (III) ) according to the method as described in WO 02/02714 (Patent document 1)

InaSchlenk's flask were placed iridium(III) trichloride hydrate (500 mg, 1.42 mmol, 1 equivalent) and silver (I) trifluoromethanesulfonate (1.09 g, 4.26 mmol, 3.0 equivalents) , and the interior of the flask was substituted with nitrogen. There were added 2- (2, 4-difluorophenyl) pyridine (2 mL, s/s=4) and water (1 L, s/s=2), and the mixture was heated at 200°C on an oil bath with stirring for 3 hours. The resulting black mixture was evaporated to dryness, and the residue was purified by silica gel column chromatography (eluent: dichloromethane) . The column fractions were condensed, and recrystallized from hexane/dichloromethane to give 571 mg of the title compound (5-6) as yellow green powder in 52.7% yield. NMR data of the product was identical to that of Example 12.

According to the processes of the present invention, it becomes possible to provide a variety of trivalent hexadentate ortho-metallated iridium complexes efficiently in a conventional way, which complexes are useful as materials for light-emitting devices.

Claims

C AIMS

1. A process for producing a trivalent hexadentate ortho-metallated iridium complex with an iridium compound and a coordination compound as starting materials, which comprises using a monovalent iridium dinuclear complex represented by the following formula (I) as a starting material:

(wherein A represents a non-conjugated diene compound; and X represents a halogen atom)

2. The process as claimed in Claim 1, wherein the trivalent hexadentate ortho-metallated iridium complex is a compound representedby the following formula (II), (III), (IV) or (V) :

(wherein the ring B represents an optionally substituted aryl group or heteroaryl group; the ring C represents an optionally substituted nitrogen-containing aryl group; the ring D represents an optionally substituted pyridyl group; the rings B and C may be taken with each other to form a fused ring; X represents a halogen atom; R¹ and R³ each represents independently an alkyl group, alkoxy group, aryl group or heteroaryl group; R² represents a hydrogen atom, alkyl group, aryl group or heteroaryl group; R¹ and R² or R² and R³ may be taken together with the adjacent carbon atom to form a ring)

3. A process for producing a trivalent hexadentate ortho-metallated iridium complex represented by the formula (ID :

(wherein the ring B represents an optionally substituted aryl group or heteroaryl group; the ring C represents an optionally substituted nitrogen-containing aryl group; the rings B and C may be taken with each other to form a fused ring; and X represents a halogen atom) which comprises reacting a monovalent iridium dinuclear complex represented by the formula (I) :

(wherein A represents a non-conjugated diene compound; and X represents a halogen atom) with a compound represented by the formula (VI) :

(wherein the ring B represents an optionally substituted aryl group or heteroaryl group; the ring C represents an optionally substituted nitrogen-containing aryl group; and the rings B and C may be taken with each other to form a fused ring)

4. A process for producing a trivalent hexadentate ortho-metallated iridium complex represented by the formula (III) :

(wherein the ring B represents an optionally substituted aryl group or heteroaryl group; the ring C represents an optionally substituted nitrogen-containing aryl group; the rings B and C may be taken with each other to form a fused ring; R¹ and R³ each represents independently an alkyl group, alkoxy group, aryl group or heteroaryl group; R² represents a hydrogen atom, alkyl group, aryl group or heteroaryl group; R¹ and R² or R² and R³ may be taken together with the adjacent carbon atom to form a ring) which comprises reacting amonovalent iridiumdinuclear complex represented by the formula (I) :

(wherein A represents a non-conjugated diene compound; and X represents a halogen atom) with a compound represented by the formula (VI)

(wherein the ring B represents an optionally substituted aryl group or heteroaryl group; the ring C represents an optionally substituted nitrogen-containing aryl group; and the rings B and C may be taken with each other to form a fused ring) , followed by reaction with a compound represented by the formula

(VII) :

(wherein R¹ and R³ each represents independently an alkyl group, alkoxy group, aryl group or heteroaryl group; R² represents a hydrogen atom, alkyl group, aryl group or heteroaryl group; and R¹ and R² or R² and R³ may be taken together with the adjacent carbon atom to form a ring)

5. The process as claimed in Claim 4 which comprises reacting a monovalent iridium dinuclear complex represented by the formula (I) with a compound represented by the formula

(VI) , followed by reaction with a compound represented by the formula (VII) in one-pot.

6. A process for producing a trivalent hexadentate ortho-metallated iridium complex represented by the formula (IV) :

(wherein the ring B represents an optionally substituted aryl group or heteroaryl group; the ring C represents an optionally substituted nitrogen-containing aryl group; the ring D represents an optionally substituted pyridyl group; and the rings B and C may be taken with each other to form a fused ring) which comprises reacting amonovalent iridium dinuclear complex represented by the formula (I) :

(wherein the ring B represents an optionally substituted aryl group or heteroaryl group; the ring C represents an optionally substituted nitrogen-containing aryl group; and the rings B and C may be taken with each other to form a fused ring) , followed by reaction with a compound represented by the formula (VIII) :

(wherein the ringDrepresents an optionally substitutedpyridyl group)

7. The process as claimed in Claim 6 which comprises reacting a monovalent iridium dinuclear complex represented by the formula (I) with a compound represented by the formula

(VI) , followed by reaction with a compound represented by the formula (VIII) in one-pot.

8. A process for producing a trivalent hexadentate ortho-metallated iridium complex represented by the formula (V) :

(wherein the ring B represents an optionally substituted aryl group or heteroaryl group; the ring C represents an optionally substituted nitrogen-containing aryl group; and the rings B and C may be taken with each other to form a fused ring) which comprises reacting a monovalent iridium dinuclear complex represented by the formula (I) :

(wherein the ring B represents an optionally substituted aryl group or heteroaryl group; the ring C represents an optionally substituted nitrogen-containing aryl group; and the rings B and C, may be taken with each other to form a fused ring) followed by reaction with a silver salt and a compound represented by the formula (VI) .

9. The process as claimed in Claim 8 which comprises reacting a monovalent iridium dinuclear complex represented by the formula (I) with a compound represented by the formula

(VI), followed by reaction with a silver salt and a compound represented by the formula (VI) in one-pot.