Title of Invention

METAL COMPLEX COMPOUND AND ORGANIC ELECTROLUMINESCENT DEVICE COMPRISING THE SAME

Abstract

The present invention relates to a metal complex compound having a. partial structure as herein described containing metals such as iridium. This invention also relates to an organic electroluminescence device which comprises at least one organic thin film layer sandwiched between a pair of electrode consisting of an anode and a cathode, wherein the organic thin film layer comprises the above metal complex compound, which emits light by applying an ele~tric voltage between the pair of electrode. An organic electroluminescence device employing the novel metal complex compound emits various phosphorous lights including blue light having an enhanced current efficiency and prolonged lifetime.

Full Text

Fffi;SCKlPTION METa\L COMPLEX WE CLAIM : 1. A metal complex compound having a partial structure represented by the following genera] formula (1); wherein R' to R^ each independently are a hydrogen atom, a cyano group, a nitro group, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted alkoxyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkylsilyl group having 1 to 20 carbon atoms, a substituted or unsubstituted acyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aromatic group having 1 to 30 carbon atoms; and a couple of R' and R'^, a couple of R^ and R** and a couple of R' and R^ optionally bond each other to form a ring structure; p and q each independently are an integer of 0 to 3; p + q being 2 or 3; further, when p is an integer of 2 or greater, the plurality of R^ optionally bond each other to form a ring structure; when q is an integer of 2 or greater, the plurality of R^ optionally bond each other to form a ring structure, with the proviso that when p is 0 and q is 2, the plurality of R^ do not bond to each other to form a ring structure and when p is 0, q is 2, and R' and R^ bond to each other to form a ring structure, the ring structure is not substituted with phenyl; and M is any one metal atom selected from iridium (Ir) atom, rhodium (Rh) atom, platinum (Pt) atom or palladium (Pd) atom. 2. The metal complex compound as claimed in claim 1, which is a materia! for a light emitting element. 3. The metal complex compound as claimed in claim 1, wherein said partial structure is represented by any one of the following general formulae (i) to (iii) and (v) to (vii); N N ^N N N (0 (ii) (vi) (vii) (iii) wherein R is the same as defined in claim 1. 4. The metal complex compound as claimed in claim 1 wherein said partial structure is represented by any one of the following general formulae (i') to (iii') and (v') to (vii'); ao tii') (iiiO (V) (viO (vii') i4 : wherein R is the same as defined in claim 1. 5. The metal complex compound as claimed in claim 1, which is represented by any one of the following general formulae I to 3, 5 to 7, I'to 3' and 5' to 7': rfU (--f~5^"0. ^n. 1 T' ?- ■>^;rV: 1' 2' 5' 6' wherein T^ to T^ each independently are a hydrogen atom, a cyano group, a nitro group, a halogen atom, a substituted or unsubstituted alkyi group having 1 to 20 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsabstituted aJkoxy! group having 1 to 20 carbon atoms, a substituted or unsubstituted alkylsilyl group having 1 to 20 carbon atoms, a substituted or unsubstituted acyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aromatic group having 1 to 30 carbon atoms; a couple of T^ and T"^, a couple of T* and T', a couple of T^ and T and a couple of T^ and T^ optionally bond each other to form a ring structure; M is any one metal atom selected from iridium (Ir) atom, rhodium (Rh) atom, platinum (Pt) atom or palladium (Pd) atom; and L' and L^ each independently are any one structure represented by the following structures; pic sun acac n is an integer of 0 to 2, and m is an integer of 0 or 1; G is any one structure represented by the following structures: Napl Nap2 Nap3 TB K^'-- TF X- OB Fu Fl Bz Qu OL wherein a dotted line "- - - - " is a covalent bond with the above M; and T' to T' in Ph each independently are a hydrogen atonij a cayno group, a nitro group, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted alkoxyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkylsilyl group having I to 20 carbon atoms or a substituted or unsubstituted acyl group having I to 20 carbon atoms and T' to T^ in 01, each independently are a hydrogen atom, a cayno group, a nitro group, a halogen atom, a substituted or unsubstituted alkyl group having I to 20 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted alkoxyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkylsilyl group having 1 to 20 carbon atoms, a substituted or unsubstituted acyl group having I to 20 carbon atoms or a substituted or unsubstituted aromatic group having 1 to 30 carbon atoms. 6. An organic electroluminescence device which comprises at least one organic thin film layer sandwiched between a pair of electrode consisting of an anode and a cathode, wherein the organic thin film layer comprises the metal complex compound as claimed in claim 1, which emits light by applying an electric voltage between the pair of electrode. 7. The organic electroluminescence device as claimed in claim 6 wherein said light emitting layer comprises said metal complex compound. 8. The organic electroluminescence device as claimed in claim 6 wherein said organic thin film layer comprising the metal complex compound is formed by a coating process. QltOAJJlC ELErTT?OLTJMlNEgCEMT DRMCE USING SAft^E TECHNICAL FIELD The present invention relates to a novel metal complex compound and an organic electroluminescence device using the compound. Particularly, the present invention relates to an organic electroluminescence device ("electroluminescence" will be referred to as "EL", hereinafter) having excellent efficiency of light emission and prolonged lifetime, and to a metal complex compound realizing it. BACKGROUND ART The organic EL devices have been expected to be appUed to color wide screen image display devices replacing liquid crystal display devices, and have been intensively developed. Recently, although displays using the organic EL devices have now been used in practical applications, full-color image display devices using the same are still in the course of development because they lack in sufficient Hght emitting property. Very high efficiency green organic light emitting devices based on electrophosphorescence employing ortho metalized iridium complex (fac-tris{2-phenylpyridine) iridium) as a phosphorus light emitting material for improving properties of the organic EL device are proposed, (refer to. for example, D. F. O'Brien and M. A. Baldo et al "Improved energy transferring electrophosphorescent devices" AppHed Physics letters Vol.74 No.3, pp442-444, January 18, 1999; and M. A. Baldo et al "Very high-efficiency green organic light emitting devices based on electrophosphorescence" Applied Physics letters Vol. 75 No. 1, pp4-6, July 5, 1999). Because the current organic EL devices employing the phosphorus photoluminescence are limited to emitting only green Hght, coverage as the color display devices is narrow. Therefore, it has been demanded to develop organic EL devices which emit hght of different colors from green with improved light emission property. Regarding particularly with EL devices which emit blue hght, those having an external quantum yield exceeding 5 % is not reported yet. Accordingly, an improvement in the EL devices which emit blue hght, if possible, enables the display devices to display full colors or white hght resultantly advancing toward practical use of phosphorus light EL device greatly. Further, although International PCT Patent Publication No. WO 02/15645 discloses following structures of ligands G\) and (B): Ri R2 RN^N (A) wherein Ri to Rs each independently represents a hydrogen atom, a halogen atom, an alkyl group, an aromatic group and an arylene group; and Ri' and R2' an aromatic group, which may bond each other; any practical synthesis example of real complex with the use of the Hgands is not described. DISCLOSURE OF THE INVENTION The present invention has been made to overcome the above problems and has an object of providing an organic EL device having an enhanced efficiency of hght emission and prolonged hfetime, and an object of providing a metal complex compound reaUzing it. As a result of intensive researches and studies to achieve the above object by the present inventors, it was found that the iridium complex proposed in the former patent hterature neither generates nor isolates stably in a case where R is H in the above Hgands (A) and (B) and that it is important for stably isolating the iridium complex to replace an atom on a side of N without forming a coordinate bond with a metal to an atom except a hydrogen atom. Then, the inventors designed hgands having various kinds of substituent on N, and succeeded in synthesizing iridium complex for the first time. Further, it was found that an employment of a metal complex compound having a partial structure represented by a following general formula (1) provides the EL device achieving an external quantum yield of 8 % and exhibits an enhanced efficiency of Ught emission not only in blue region but also about various phosphorus photoluminescence and prolonged lifetime, resultantly completing the present invention. Namely, the present invention provides a metal complex compound having a partial structure represented by a following general formula (I): ( R3-C) (1) wherein R^ to R^ each independently represents a hydrogen atom, a cyano group. a nitro group, a halogen atom, a substituted or unsubatituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubatituted amino group, a substituted or unsubstituted alkoxyl group having 1 to 20 carbon atoms, a substituted or unsubatituted alkylsilyl group having 1 to 20 carbon atoms, a substituted or unsubstituted acyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aromatic group having 1 to 30 carbon atoms; and a couple of R' and R2, a couple of R^ and R^, a couple of R^ and R^ and a couple of R* and R'^ may bond each other to form a ring structure; p and q each independently represents an integer of 0 to 3; p + q being 2 or 3; further, when p is an integer of 2 or greater, plural of R^ may bond each other to form a ring structure; when q is an integer of 2 or greater, plural of R^ may bond each other to form a ring structure; and M represents any one metal ^tom selected from iridium (Ir) atom, rhodium (Rh) atom, platinum (Pt) atom or palladium (Pd) atom. Further, the present invention provides an organic EL device which comprises at least one organic thin film layer sandwiched between a pair of electrode consisting of an anode and a cathode, wherein the organic thin film layer comprises the above metal complex compound, which emits light by applying an electric voltage between the pair of electrode. THE PREFERRED EMBODIMENT TO CARRY OUT THE INVENTION The present invention provides a metal complex compound having a partial structure represented by a following general formula (1): (R'-c)p , 'N_(C-R5), R" (I) In the general formula (I), R' to R^ each independently represents a hydrogen atom, a cyano group, a nitro group atom, a halogen atom, a substituted or unsubstituted aLkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted alkoxyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkylailyl group having 1 to 20 carbon atoms, a substituted or unsubstituted acyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aromatic group having 1 to 30 carbon atoms; and a couple of R' and R^, a couple of R^ and R^, a couple of R^ and R^ and a couple of R' and R^ may bond each other to form a ring structure. Examples of the halogen atom include fluorine atom, chlorine atom, bromine atom and iodine atom. Examples of the alkyl group described above include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, etc. The alkoxy group is expressed as —OY, wherein Y represents the same as the foregoing description about the alkyl group. Examples of the alkylsilyl group include trimethylsilyl group, t- butyldimethylsUyl group, etc. Examples of the acyl gi*oup include acetyl group, propionyl group, butyryl group, isobutyryl group, etc. Examples of the above aromatic group include benzene, naphthalene, anthracene, phenanthrene, pyrene, coronene, biphenyl, terphenyl, pyrrole, furan, thiophene, benzothiophene, oxadiazoline, diphenylanthracene, indoline, carbazole, pyridine, benzoquinone, fluoranthene, acenaphtho fluoranthene, etc. Further, examples of the substituent for those groups include cyano group, hydroxyl group, nitro group, halogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted amino group, substituted or unsubstituted alkoxyl group, substituted or unsubstituted alkylsilyl group, substituted or unsubstituted acyl group, substituted or unsubstituted aromatic group, substituted or unsubstituted alkenyl group, a substituted or unsubstituted cycloalkyl group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted arylalkyl group, a substituted or unsubstituted aryloxy group, substituted or unsubstituted alkoxycarbonyl group, carboxyl group, etc. Examples of the ring structure formed by bonding R^ and R^, R^ and R*, or R'* and R'* each independently include benzene, pyridine, naphthalene, benzothiazole. quinoUne, etc. It is preferable that R' to R^ each independently represents a hydrogen atom, a cyano group, a nitro group, a fluorine atom, a trifluoromethyl group, a dimethylamino group, a methoxy group, a t-butyl group, a trimethylsilyl group and an acetyl group. In the general formula (I), p and q each independently represents an integer of 0 to 3 (preferably 0 to 2); p + q being 2 or 3; further, when p is an integer of 2 or greater, plural of R^ may bond each other to form a ring structure; when q is an integer of 2 or greater, plural of R^ may bond each other to form a ring structure. Examples of the ring structure formed by plural of R^ and plural of R^ each independently include benzene, pyridine, etc. In the general formula (1), M represents any one metal atom selected from iridium (Ir) atom, rhodium (Rh) atom, platinum (Pt) atom or paUadium (Pd) atom; while Ir and Pt are preferable and Ir is more preferable.. Further, it is preferable that the partial structure represented by general formula (I) is expressed by any one of (i) to (vii) or GO to (viiO below, while (i) to (iii) being further preferable. ■-i^V,./% (i) (ii) Oii) (vO (vii) (iO (iiO GiiO (ivO (vO (viO (viiO Furthermore, it is preferable that the metal complex compound of the present invention has basic skeletal structure expressed by following general formulae 1 to 7 and I' to 7'. 'L'7--MV'/n V 2' 3' 5' 6' 7' In the general formulae 1 to 7 and 1' to 7', T^ to T^ each independently represents a hydrogen atom, a cyano group, a nitro group atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted aUtoxyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkylsilyl group having 1 to 20 carbon atoms, a substituted or unsubstituted acyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aromatic group having 1 to 30 carbon atom. Further, a couple of T^ and T*', a couple of T* and T', a couple of T'^ and T* and a couple of T^ and V may bond each other to form a ring structure. Examples of the above halogen atom, alkyl group, alkoxyl group, alkylsilyl group, acyl group, aromatic group, these substituents, and these preferable examples are the same as explained about R' to R' in the general formula (I). Moreover, examples of the ring structure formed by bonding the couple of T^ and T', the couple of T^^ and T^ the couple of T" and T^ and the couple of T^ and T^ each independently include benzene, pyridine, etc. In the general formulae 1 to 7 and I'to 7', M is the same as the forgoing description. In the general formulae 1 to 7 and I'to 7'. L' and U are each expressed by any one of the following structures: facac piC Sim acac In the general formulae 1 to 7 and I'to 7', n represents an integer of 0 to 2, preferably 0 or 1, m represents an integer of 0 or 1. In the general formulae 1 to 7 and 1' to 7', G is a group expressed by any one of groups below. ■■^, s. Ph Napl Nap2 Nap3 TB TF OB Fu // Bz Qu KJ-. OL In the above groups, a dotted hne "----" represents a covalent bond with M. T' to T"* in the above Ph and OL each may independently represents a hydrogen atom, a cyano group, a nitre group, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted alkoxyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkylsUyl group having 1 to 20 carbon atoms, a substituted or unsubstituted acyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aromatic group having 1 to 30 carbon atom. Examples ef those groups, their substituents and those preferable examples are the same as explained about R' to R^ in the general formula (I). Further, examples of the substituent forming the ring structure by bonding the couple of T^ and T^, the couple of T^ and T^ or the couple of T^ and T'* in the Ph include a divalent group expressed by any one of groups below, while BL, MESl, MES2, PSl and PS2 being preferable. —OCCH2CH2— 0 —COCH2— 0 PME 2 MES 1 —OCCH2— 11 0 —CH2OC— 0 —CH2C0^ II o MES 2 —OCH2C- II 0 —CCH2O- II o EE 1 EE 2 MS 1 MS 2 However, the group with a smaller number of superscript among T' to T' bonds to the left of the divalent group and the group with a greater number superscript among T' to T'* bonds to the right of the divalent group. Specific examples of the metal complex compound having any one basic skeletal structure among the general formulae 1' to 7' will be shown in Tables below, though not hmited thereto. In the Tables below, T' to T^, L' and U (in the cases of the basic skeletal structures 1 to 4 and 1' to 4") or T' to T', L' and L^ (in the cases of the basic skeletal structures 5 to 7 and 5' to 7') are described within the columns righter to the basic skeletal structures. T* .T' W N-" ^'-'l-=/n fS TV^ Further in the Tables below, "BBS" means Basic Skeletal Structure, and 'BS" means Skeletal Structure.

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0273-chenp-2006 abstract.pdf

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0273-chenp-2006 claims.pdf

0273-chenp-2006 correspondence-others.pdf

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0273-chenp-2006 description (compelet) 2.pdf

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