JP5130512B2 - Carboxylic acid-diketone complex rare earth metal complex - Google Patents

Description

  The present invention relates to a rare earth metal complex having a carboxylic acid organic ligand, and more specifically, for example, a light emitting material for an organic electroluminescence element (hereinafter, abbreviated as an organic EL element), an organic zeolite having a light emitting function, and light emission. The present invention relates to a rare earth metal complex that can be suitably used as a reactive adsorbent, a luminescent high-sensitivity molecular sensor, a luminescent high-sensitivity chiral sensor, a biological contrast agent, a reaction catalyst, and the like.

An organic aluminum complex (Alq ₃ ) having excellent EL quantum yield and durability has been put to practical use as a light-emitting material for organic EL elements. On the other hand, most light emitting materials using rare earth metals are inorganic light emitting materials made of inorganic compounds.
When a rare earth metal is directly excited, its energy efficiency becomes a problem. For this reason, it has been studied to increase the efficiency of light emission by arranging a material that easily absorbs energy around the rare earth metal and utilizing the energy transfer therefrom.
For example, for inorganic light emitting materials using rare earth metals, a method of adding a small amount of rare earth metal ions to an inorganic compound mother crystal that easily absorbs energy is the mainstream. This inorganic luminescent material has been put into practical use in color televisions, fluorescent lamps and the like.

For organic light emitting materials containing rare earth metals, a method (complexation) is generally used in which the rare earth metal ions are covered with a certain organic ligand.
Rare earth organic complexes are expected to have (1) increased rare earth metal ion density, (2) increased monochromaticity due to sequestration of rare earth metal ions, and (3) improved EL quantum yield compared to inorganic light emitting materials. However, at present, few materials have been found that are excellent in terms of EL quantum yield. There are also many problems in terms of durability (light stability, thermal stability) and workability.

Until now, as a rare earth metal complex having a carboxylic acid-based aromatic organic ligand, a complex represented by the following formula has been known (Patent Document 1: Japanese Patent Application Laid-Open No. 2004-176306).
However, these metal complexes have extremely low solubility in organic solvents, and because they do not have vapor deposition ability because they cause thermal decomposition, it is difficult to form a uniform film, and they have a problem of poor practicality. Yes.

（式中、Ｍは、希土類金属を表す。）

(In the formula, M represents a rare earth metal.)

JP 2004-176306 A

  The present invention has been made in view of such circumstances, exhibits excellent monochromatic emission derived from rare earth metal ions, and is excellent in solubility in organic solvents, vapor deposition by sublimation, heat resistance, and the like. Another object is to provide a rare earth metal complex.

  As a result of intensive studies to achieve the above object, the present inventors have obtained 1,3-diketone compounds as rare earth metal complexes having (substituted) aromatic or (substituted) heterocyclic carboxylic acid-based organic ligands. And / or a complex ligand-based rare earth metal complex coordinated with a nitrogen-containing heterocyclic compound exhibits good monochromatic emission derived from rare earth metal ions, and is soluble in an organic solvent, vapor-deposited, and heat-resistant The present invention has been completed by finding that it can be a light emitting material having excellent properties.

〔式中、Ｒ ³ およびＲ ⁴ は、それぞれ独立して、炭素数１〜１０のアルキル基、炭素数１〜１０のハロゲノアルキル基、Ｚで置換されていてもよいアリール基、Ｚで置換されていてもよいヘテロ環基またはＺで置換されていてもよいアラルキル基を表す。Ｑは、酸素原子を表すが、存在しなくともよい。Ｒ ⁵ 、Ｒ ⁶ およびＲ ⁷ は、それぞれ独立して、水素原子、ハロゲン原子、シアノ基、炭素数１〜１０のアルキル基、炭素数１〜１０のアルコキシ基、炭素数１〜１０のアルコキシカルボニル基、ニトロ基、Ｚで置換されていてもよいフェニル基、Ｚで置換されていてもよいナフチル基、Ｚで置換されていてもよいビフェニル基またはＺで置換されていてもよいアントリル基を表す。Ｚは、ハロゲン原子、シアノ基、ニトロ基、炭素数１〜１０のアルキル基、炭素数１〜１０のハロゲノアルキル基、炭素数１〜１０のアルコキシ基、炭素数１〜１０のハロゲノアルコキシ基、炭素数１〜１０のアルコキシカルボニル基、フェニル基またはナフチル基を表す。
Ｍは、３価の希土類金属を表す。Ｂは、Ｚで置換されていてもよい含窒素へテロ環化合物（Ｚは、前記と同じ。）を表す。
ｒ、ｓおよびｔは、１〜４の整数を表し、ｎ′は、１〜３の整数を表し、ｍ′は、０〜３の整数を表す。〕
２． 前記Ｒ ³ およびＲ ⁴ が、それぞれ独立して、炭素数１〜１０のアルキル基、炭素数１〜１０のハロゲノアルキル基、Ｚで置換されていてもよいフェニル基またはＺで置換されていてもよいチエニル基を表し、前記Ｚが炭素数１〜１０のアルキル基、炭素数１〜１０のハロゲノアルキル基、炭素数１〜１０のアルコキシ基または炭素数１〜１０のハロゲノアルコキシ基を表し、前記Ｒ ⁵ 、Ｒ ⁶ およびＲ ⁷ が全て水素原子、前記ｒ、ｓおよびｔが全て１、前記Ｑが存在しない、前記ＢがＺで置換されていてもよいフェナントロリンである１のカルボン酸−ジケトン複合系希土類金属錯体、
３． 前記含窒素ヘテロ環化合物が、１，１０−フェナントロリンである１または２のカルボン酸−ジケトン複合系希土類金属錯体、
４． 前記Ｒ ³ が、チオフェン−２−イル基である１〜３のいずれかのカルボン酸−ジケトン複合系希土類金属錯体、
５． 前記Ｒ ⁴ が、トリフルオロメチル基である１〜４のいずれかのカルボン酸−ジケトン複合系希土類金属錯体、
６． 前記希土類金属が、ユウロピウム（Ｅｕ）またはテルビウム（Ｔｂ）である１〜５のいずれかのカルボン酸−ジケトン複合系希土類金属錯体、
７． １〜６のいずれかの希土類金属錯体を含むことを特徴とする発光材
を提供する。 That is, the present invention
1. A carboxylic acid-diketone composite rare earth metal complex represented by the formula ( 5 ):

Wherein, R ³ and R ⁴ are each independently an alkyl group having a carbon number of 1 to 10, halogenoalkyl group having 1 to 10 carbon atoms, an aryl group which may be substituted with Z, are substituted with Z Represents an optionally substituted heterocyclic group or an aralkyl group optionally substituted with Z. Q represents an oxygen atom, but may not be present. R ⁵ , R ⁶ and R ⁷ are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkoxycarbonyl having 1 to 10 carbon atoms. A nitro group, a phenyl group optionally substituted with Z, a naphthyl group optionally substituted with Z, a biphenyl group optionally substituted with Z, or an anthryl group optionally substituted with Z . Z is a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 10 carbon atoms, alkoxycarbonyl group having 1 to 10 carbon atoms, a full Eniru group or a naphthyl group.
M represents a trivalent rare earth metal. B represents a nitrogen-containing heterocyclic compound optionally substituted with Z (Z is the same as described above).
r, s, and t represent an integer of 1 to 4, n ′ represents an integer of 1 to 3, and m ′ represents an integer of 0 to 3. ]
2. R ³ and R ⁴ are each independently an alkyl group having 1 to 10 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, a phenyl group which may be substituted with Z, or a substituent with Z. Represents a good thienyl group, Z represents an alkyl group having 1 to 10 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms or a halogenoalkoxy group having 1 to 10 carbon atoms, R ^5, R ⁶ and R ⁷ are all hydrogen atoms, the r, s and t are all 1, wherein Q is absent, one carboxylic acid wherein B is Ru may phenanthroline der optionally substituted by Z - diketone Composite rare earth metal complexes,
3. The nitrogen-containing heterocyclic compounds, Ru 1,10 der 1 or 2 carboxylic acid - diketone complex rare earth metal complex,
4). Wherein R ³ is either a carboxylic acid of 1-3 Ru thiophen-2-yl group Der - diketone complex rare earth metal complex,
5. The carboxylic acid-diketone composite rare earth metal complex according to any one of 1 to 4, wherein R ⁴ is a trifluoromethyl group ,
6). The carboxylic acid-diketone composite rare earth metal complex according to any one of 1 to 5, wherein the rare earth metal is europium (Eu) or terbium (Tb) ,
7). A light-emitting material comprising any one of 1 to 6 rare earth metal complexes is provided.

The rare earth metal complex of the present invention exhibits good monochromatic emission derived from rare earth metal ions, and is excellent in solubility in organic solvents, heat resistance, fluorescence quantum yield, and the like. In addition, in the complex in which the nitrogen-containing heterocyclic compound ligand is coordinated, the sublimation property is remarkably increased, and thus the vapor deposition performance is excellent. Thus, since the rare earth metal complex of the present invention is excellent in the solubility of the organic solvent and the vapor deposition performance, it is easy to form a uniform film.
The rare earth metal complex of the present invention having such characteristics includes a light emitting layer of an organic EL device, an organic zeolite having a light emitting function, a light emitting adsorbent, a light emitting high sensitivity molecular sensor, a light emitting high sensitivity chiral sensor, a biological contrast agent, It can be suitably used as a reaction catalyst.

Hereinafter, the present invention will be described in more detail.
The carboxylic acid-diketone composite rare earth metal complex according to the present invention includes a carboxylic acid ligand represented by the following formula (1), a 1,3-diketone compound ligand represented by the following formula (2), and a trivalent rare earth metal. It consists of.

（式中、Ａ、Ｒ¹、Ｒ²、Ｒ³およびＲ⁴は、上記と同じ意味を表す。）

(In the formula, A, R ¹ , R ² , R ³ and R ⁴ have the same meaning as described above.)

Here, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
The alkyl group having 1 to 10 carbon atoms may be linear, branched or cyclic. For example, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, s- Butyl, n-pentyl, n-hexyl, 2-ethylpropyl, 2,2-dimethylpropyl, 1,2-dimethylpropyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl -1-methylpropyl, 1-ethyl-2-methylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2, 2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1-methylpentyl, 2-methyl Pentyl, 3-methylpentyl, 4-methylpentyl, and the like.

Examples of the halogenoalkyl group having 1 to 10 carbon atoms include groups in which at least one hydrogen atom of each alkyl group is substituted with a halogen atom. Specifically, CH ₂ F, CHF ₂ , CF _{3, CH 2 CH 2 F,} CH 2 CHF 2, CH 2 CF 3, CH 2 CH 2 CH 2 F, CH 2 CH 2 CHF 2, CH 2 CH 2 CF 3, CH 2 Cl, CHCl 2, CCl 3, CH ₂ CH ₂ Cl, CH ₂ Br, CHBr ₂ , CBr ₃ , CH ₂ CH ₂ Br and the like can be mentioned.

  The alkoxy group having 1 to 10 carbon atoms may be linear, branched or cyclic. For example, methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t- Butoxy, n-pentyloxy, n-hexyloxy, 1,1-dimethylpropoxy, 1,2-dimethylpropoxy, 2,2-dimethylpropoxy, 1-ethylpropoxy, 1,1,2-trimethylpropoxy, 1,2 , 2-trimethylpropoxy, 1-ethyl-1-methylpropoxy, 1-ethyl-2-methylpropoxy, 1-methylbutoxy, 2-methylbutoxy, 3-methylbutoxy, 1-ethylbutoxy, 2-ethylbutoxy, 1 , 1-dimethylbutoxy, 1,2-dimethylbutoxy, 1,3-dimethylbutoxy, 2,2-dimethyl Butoxy, 2,3-dimethylbutoxy, 3,3-dimethylbutoxy, 1-methylpentyloxy, 2-methylpentyloxy, 3-methylpentyloxy, 4-methylpentyloxy and the like.

The alkoxycarbonyl group having 1 to 10 carbon atoms may be linear, branched or cyclic. For example, methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, i-propoxycarbonyl, n-butoxycarbonyl, i-butoxycarbonyl , S-butoxycarbonyl, t-butoxycarbonyl, n-pentyloxycarbonyl, n-hexyloxycarbonyl, 1,1-dimethylpropoxycarbonyl, 1,2-dimethylpropoxycarbonyl, 2,2-dimethylpropoxycarbonyl, 1-ethyl Propoxycarbonyl, 1,1,2-trimethylpropoxycarbonyl, 1,2,2-trimethylpropoxycarbonyl, 1-ethyl-1-methylpropoxycarbonyl, 1-ethyl-2-methylpropoxycarbonyl, 1 Methylbutoxycarbonyl, 2-methylbutoxycarbonyl, 3-methylbutoxycarbonyl, 1-ethylbutoxycarbonyl, 2-ethylbutoxycarbonyl, 1,1-dimethylbutoxycarbonyl, 1,2-dimethylbutoxycarbonyl, 1,3-dimethylbutoxy Carbonyl, 2,2-dimethylbutoxycarbonyl, 2,3-dimethylbutoxycarbonyl, 3,3-dimethylbutoxycarbonyl, 1-methylpentyloxycarbonyl, 2-methylpentyloxycarbonyl, 3-methylpentyloxycarbonyl, 4-methyl Examples include pentyloxycarbonyl.
In the above, n represents normal, i represents iso, s represents secondary, and t represents tertiary.

  Examples of the phenyl group which may be substituted with Z, the naphthyl group which may be substituted with Z, and the biphenyl group which may be substituted with Z include, for example, phenyl, o-methylphenyl, m-methylphenyl, p -Methylphenyl, o-trifluoromethylphenyl, m-trifluoromethylphenyl, p-trifluoromethylphenyl, p-ethylphenyl, pi-propylphenyl, pt-butylphenyl, o-chlorophenyl, m -Chlorophenyl, p-chlorophenyl, o-bromophenyl, m-bromophenyl, p-bromophenyl, o-fluorophenyl, p-fluorophenyl, o-methoxyphenyl, m-methoxyphenyl, p-methoxyphenyl, o -Trifluoromethoxyphenyl, p-trifluoromethoxyphenyl, o-ni Rophenyl, m-nitrophenyl, p-nitrophenyl, p-cyanophenyl, 3,5-dimethylphenyl, 3,5-bistrifluoromethylphenyl, 3,5-dimethoxyphenyl, 3,5-bistrifluoromethoxyphenyl, 3 , 5-diethylphenyl, 3,5-di-i-propylphenyl, 3,5-dichlorophenyl, 3,5-dibromophenyl, 3,5-difluorophenyl, 3,5-dinitrophenyl, 3,5- Dicyanophenyl, 2,4,6-trimethylphenyl, 2,4,6-tristrifluoromethylphenyl, 2,4,6-trimethoxyphenyl, 2,4,6-tristrifluoromethoxyphenyl, 2,4 6-trichlorophenyl, 2,4,6-tribromophenyl, 2,4,6-trifluorophenyl, α-naphth Examples include til, β-naphthyl, o-biphenylyl, m-biphenylyl, and p-biphenylyl groups.

  Examples of the anthryl group optionally substituted with Z include 1-anthryl, 2-anthryl, 9-anthryl, 1-methyl-9-anthryl, 1-methyl-10-anthryl, 9-methyl-10-anthryl group and the like. Is mentioned. Diarylphosphino group optionally substituted with Z, diheteroarylphosphino group optionally substituted with Z, dialkylphosphino group having 1 to 10 carbon atoms, alkylarylphosphino group having 1 to 10 carbon atoms As the alkylheteroarylphosphino group having 1 to 10 carbon atoms, diphenylphosphino, phenylbiphenylphosphino, dibiphenylphosphino, dianthrylphosphino, dipyridylphosphino, dithienylphosphino, difurylphosphino, diphenylphosphino Pyrazolylphosphino, diimidazolylphosphino, dimethylphosphino, diethylphosphino, di-n-butylphosphino, di-n-octylphosphino, di-n-decylphosphino, methylphenylphosphino, ethylphenylphosphino, n-butylphenyl Phosphino, n-oct Ruphenylphosphino, n-decylphenylphosphino, methylpyridylphosphino, methylthienylphosphino, methylfurylphosphino, methylpyrazolylphosphino, methylimidazolylphosphino, ethylpyridylphosphino, ethylthienylphosphino, ethylfurylphosphino Fino, ethylpyrazolylphosphino, ethylimidazolylphosphino, n-butylpyridylphosphino, n-butylthienylphosphino, n-butylfurylphosphino, n-butylpyrazolylphosphino, n-butylimidazolylphosphino, n-octyl Pyridylphosphino, n-octylthienylphosphino, n-octylfurylphosphino, n-octylpyrazolylphosphino, n-octylimidazolylphosphino, n-decylpyridylphosphino , N- decyl thienyl phosphino, n- decyl furyl phosphino, n- decyl pyrazolyl phosphino, etc. n- decyl imidazolylmethyl phosphino group.

  Examples of the aromatic hydrocarbon group optionally substituted with Z include phenyl, o-methylphenyl, m-methylphenyl, p-methylphenyl, o-trifluoromethylphenyl, m-trifluoromethylphenyl, p. -Trifluoromethylphenyl, p-ethylphenyl, pi-propylphenyl, pt-butylphenyl, o-chlorophenyl, m-chlorophenyl, p-chlorophenyl, o-bromophenyl, m-bromophenyl, p-bromophenyl, o-fluorophenyl, p-fluorophenyl, o-methoxyphenyl, m-methoxyphenyl, p-methoxyphenyl, o-trifluoromethoxyphenyl, p-trifluoromethoxyphenyl, o-nitrophenyl, m -Nitrophenyl, p-nitrophenyl, p-cyanophe 3,5-dimethylphenyl, 3,5-bistrifluoromethylphenyl, 3,5-dimethoxyphenyl, 3,5-bistrifluoromethoxyphenyl, 3,5-diethylphenyl, 3,5-di-i-propyl Phenyl, 3,5-dichlorophenyl, 3,5-dibromophenyl, 3,5-difluorophenyl, 3,5-dinitrophenyl, 3,5-dicyanophenyl, 2,4,6-trimethylphenyl, 2,4 , 6-tristrifluoromethylphenyl, 2,4,6-trimethoxyphenyl, 2,4,6-tristrifluoromethoxyphenyl, 2,4,6-trichlorophenyl, 2,4,6-tribromophenyl, 2,4,6-trifluorophenyl, α-naphthyl, β-naphthyl, o-biphenylyl, m-biphenylyl, p-biphenyl Group, and the like.

  The heterocyclic group which may be substituted with Z includes pyridyl, 2,6-dimethylpyridyl, 2,4,6-trimethylpyridyl, 2-phenylpyridyl, 2- (2,4-difluorophenyl) pyridyl, 2 -(2-thienyl) pyridyl, 2,2'-bipyridyl, 2,2'-bi (6-methylpyridyl), 2-benzothiazolyl-2-pyridyl, 2,2 ', 6', 2 ''-terpyridyl, Quinolyl, 2-phenylquinolyl, isoquinolyl, 1-phenylisoquinolyl, quinoxalyl, indolyl, 4-methylindolyl, 1,10-phenanthryl, 2,9-dimethyl-1,10-phenanthryl, 5,6-dimethyl -1,10-phenanthryl, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthryl, 4,7-bis (2-phenylvinyl) L) -1,10-phenanthryl, phenazine and the like.

  Examples of the aralkyl group optionally substituted with Z include phenylmethyl (benzyl), o-methylphenylmethyl, m-methylphenylmethyl, p-methylphenylmethyl, o-trifluoromethylphenylmethyl, m-trimethyl. Fluoromethylphenylmethyl, p-trifluoromethylphenylmethyl, p-ethylphenylmethyl, pi-propylphenylmethyl, pt-butylphenylmethyl, o-chlorophenylmethyl, m-chlorophenylmethyl, p-chloro Phenylmethyl, o-bromophenylmethyl, m-bromophenylmethyl, p-bromophenylmethyl, o-fluorophenylmethyl, p-fluorophenylmethyl, o-methoxyphenylmethyl, m-methoxyphenylmethyl, p-methoxyphenylmethyl , O-tri Fluoromethoxyphenylmethyl, p-trifluoromethoxyphenylmethyl, o-nitrophenylmethyl, m-nitrophenylmethyl, p-nitrophenylmethyl, p-cyanophenylmethyl, 3,5-dimethylphenylmethyl, 3,5- Bistrifluoromethylphenylmethyl, 3,5-dimethoxyphenylmethyl, 3,5-bistrifluoromethoxyphenylmethyl, 3,5-diethylphenylmethyl, 3,5-di-i-propylphenylmethyl, 3,5-dichloro Phenylmethyl, 3,5-dibromophenylmethyl, 3,5-difluorophenylmethyl, 3,5-dinitrophenylmethyl, 3,5-dicyanophenylmethyl, 2,4,6-trimethylphenylmethyl, 2,4,6 -Tristrifluoromethylphenylmethyl, 2,4 6-trimethoxyphenylmethyl, 2,4,6-tristrifluoromethoxyphenylmethyl, 2,4,6-trichlorophenylmethyl, 2,4,6-tribromophenylmethyl, 2,4,6-trifluorophenyl Methyl, α-naphthylmethyl, β-naphthylmethyl, o-biphenylylmethyl, m-biphenylylmethyl, p-biphenylylmethyl, thiophen-2-ylmethyl, thiophen-3-ylmethyl, furan-2-ylmethyl, furan- Examples include 3-ylmethyl, pyrrol-1-ylmethyl, pyrrol-2-ylmethyl, and pyrrol-3-ylmethyl groups.

  A benzene ring optionally substituted with Z in A, a naphthalene ring optionally substituted with Z, an anthracene ring optionally substituted with Z, a pyridine ring optionally substituted with Z, substituted with Z Examples of the optionally substituted thiophene ring, the furan ring optionally substituted with Z, the pyrazole ring optionally substituted with Z, and the imidazole ring optionally substituted with Z are represented by the following formulae, for example. Things. These rings may be substituted with any number of Z.

  Examples of the carboxylic acid ligand represented by the formula (1) include those represented by the following formula.

（式中、Ｒ⁵、Ｒ⁶、Ｒ⁷、Ｑ、ｒ、ｓおよびｔは、上記と同じ意味を表す。Ｒ⁸は、Ｒ⁷と同じ意味を表し、ｕは、ｔと同じ意味を表す。）

(In the formula, R ⁵ , R ⁶ , R ⁷ , Q, r, s and t represent the same meaning as described above. R ⁸ represents the same meaning as R ^7, and u represents the same meaning as t. .)

  In consideration of solubility of the rare earth metal complex in an organic solvent, sublimation property, and the like, diphenylphosphino or diphenylphosphonobenzoic acid compounds represented by the following formula are particularly preferable.

（式中、Ｒ⁵、Ｒ⁶、Ｒ⁷、Ｑ、ｒ、ｓおよびｔは、上記と同じ意味を表す。）

(In the formula, R ⁵ , R ⁶ , R ⁷ , Q, r, s and t have the same meaning as described above.)

  Furthermore, in view of availability, diphenylphosphinobenzoic acid and diphenylphosphonobenzoic acid represented by the following formula (7) are preferable.

  On the other hand, examples of the 1,3-diketone compound ligand represented by the formula (2) include those represented by the following formula.

  Among these, 4,4,4-trifluoro-1- (2-thienyl) -1,3-butanediol (TTA) represented by the following formula is preferable. By using this, the solubility and sublimation property of the rare earth metal complex in the organic solvent are further improved, and the emission intensity is further improved.

Examples of the trivalent rare earth metal include Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Among these, lanthanide-based metals are preferable, and Eu and Tb excellent in emission intensity are particularly preferable, and Eu is optimal.
As the precursor of the trivalent rare earth metal, an inorganic acid or organic acid salt of the rare earth metal is generally used. The inorganic acid and organic acid are not particularly limited, but generally hydrochloric acid, nitric acid, sulfuric acid, carbonic acid, acetic acid, and the like are used.
When the inorganic acid or organic acid is a monovalent acid, this salt is represented by the formula (8), and when it is a divalent acid, this salt is represented by the formula (9).

（式中、Ｍは３価の希土類金属を表し、Ｇ¹は、１価の酸に由来する陰イオンを表し、Ｇ²は、２価の酸に由来する陰イオンを表す。）

(In the formula, M represents a trivalent rare earth metal, G ¹ represents an anion derived from a monovalent acid, and G ² represents an anion derived from a divalent acid.)

The rare earth metal complex of the present invention is preferably one in which a nitrogen-containing heterocyclic compound ligand is coordinated. Thereby, the sublimation property of the rare earth metal complex can be further improved, and a uniform film can be easily formed by a vapor deposition operation.
As a nitrogen-containing heterocyclic compound ligand, what is shown by a following formula is mentioned, for example.

  Among these, phenanthroline compounds are preferable from the viewpoint of improving the above-described sublimation property, and in particular, 1,10-phenanthroline represented by the following formula is optimal.

（式中、Ａ、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｍ、Ｇ¹、Ｇ²、ｎは、上記と同じ。） The rare earth metal complex of the present invention can be produced, for example, by the following scheme.

(In the formula, A, R ¹ , R ² , R ³ , R ⁴ , M, G ¹ , G ² and n are the same as above.)

That is, the carboxylic acid ligand represented by the above formula (1), the 1,3-diketone compound ligand represented by the formula (2), and the rare earth metal acid salt (8) or (9) are mixed with water in the presence of a base. A carboxylic acid-diketone composite rare earth metal complex can be produced by reacting in an organic solvent.
In this case, examples of the base include alkali metal or alkaline earth metal hydroxides, carbonates, organic acid salts, and the like. Specific examples include sodium hydroxide, potassium hydroxide, sodium hydrogen carbonate, sodium carbonate, and the like. Can be mentioned.
As the organic solvent, alcohols such as methanol and ethanol can be used. The amount of reaction solvent used is preferably 2 to 20 times the mass of the total ligand.
0-150 degreeC is preferable and, as for reaction temperature, 10-100 degreeC is more preferable. The reaction time is usually about 1 to 24 hours.
Since the reaction product precipitates, it is collected by filtration, washed thoroughly with water or alcohol, and dried under reduced pressure to obtain the desired product as a white to pale yellow powder.
Although the structure of the target product obtained by the above reaction is not certain, it is presumed that the structure represented by the following formula (3) exists at least in part.

（式中、Ａ、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｍ、ｎは、上記と同じ。）

(In the formula, A, R ¹ , R ² , R ³ , R ⁴ , M, and n are the same as above.)

Further, when a nitrogen-containing heterocyclic compound ligand is further coordinated to the carboxylic acid-diketone composite rare earth metal complex of the present invention, in the reaction of the above scheme, 1 to 3 times moles of nitrogen-containing is added to the rare earth metal. A heterocyclic compound (B) may be added. The reaction conditions in this case are the same as above. In addition, a nitrogen-containing heterocyclic compound can also be added in the case of reaction of the said scheme.
Although the structure of the complex coordinated with the nitrogen-containing heterocyclic compound ligand is not clear, it is presumed that the structure represented by the following formula (4) exists at least in part.

〔式中、Ａ、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｍ、Ｂ、ｎ、ｍは、上記と同じ。〕

[Wherein, A, R ¹ , R ² , R ³ , R ⁴ , M, B, n, m are the same as above. ]

  When a diphenylphosphinobenzoic acid compound or diphenylphosphonobenzoic acid compound of formula (6) is used as the carboxylic acid ligand, a rare earth metal complex having a structure of the following formula (5) is obtained at least in part. It is estimated that

〔式中、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、Ｒ⁸、Ｑ、Ｍ、Ｂ、ｒ、ｓ、ｔ、ｎ′、ｍ′は、上記と同じ。〕

[Wherein R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , Q, M, B, r, s, t, n ′, m ′ are the same as described above. ]

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limited to the following Example. The elemental analysis value was measured using a CHN / O elemental analyzer: PE2400 Series II (manufactured by Perkin Elmer).

Comparative Example 1 Synthesis of 4-diphenylphosphinobenzoic acid-europium complex

4-Diphenylphosphinobenzoic acid-sodium salt (0.2 g, 0.65 mmol) was dissolved in water (about 120 mL). A solution prepared by dissolving europium chloride hexahydrate (0.0804 g, 0.22 mmol) in water (5 mL) was slowly added dropwise to this aqueous solution. The obtained white precipitate was collected by filtration with a Kiriyama funnel, sufficiently washed with water, and dried to obtain the desired product (yield 79%).
From the following analysis values, it was confirmed to be an object having the above structure.
Elemental analysis (wt%): C: 60.5, H: 4.0 [theoretical value: C: 60.5, H: 4.4 as 7 molecules of water for 2 molecules of the target product]

Comparative Example 2 Synthesis of 4-diphenylphosphinobenzoic acid-terbium complex

4-Diphenylphosphinobenzoic acid-sodium salt (0.2 g, 0.65 mmol) was dissolved in water (about 120 mL). To this aqueous solution, a solution of terbium chloride hexahydrate (0.0812 g, 0.22 mmol) dissolved in water (5 mL) was slowly added dropwise. The obtained white precipitate was collected by filtration with a Kiriyama funnel, sufficiently washed with water, and dried to obtain the desired product (yield 76%).
From the following analysis values, it was confirmed to be an object having the above structure.
Elemental analysis (wt%): C: 62.0, H: 3.9 [theoretical value: C: 61.6, H: 4.2 as two molecules of water for one molecule of the target product]

Comparative Example 3 Synthesis of 4- (4-hydroxyphenyl) benzoic acid-europium complex

4- (4-Hydroxyphenyl) benzoic acid-sodium salt (0.2 g, 0.93 mmol) was dissolved in water (about 120 mL). A solution prepared by dissolving europium chloride hexahydrate (0.1136 g, 0.31 mmol) in water (5 mL) was slowly added dropwise to this aqueous solution. The obtained white precipitate was collected by filtration with a Kiriyama funnel, sufficiently washed with water, and dried to obtain the desired product (yield 85%).
From the following analysis values, it was confirmed to be an object having the above structure.
Elemental analysis (wt%): C: 56.5, H: 3.6 [theoretical value: C: 55.4, H: 3.9 as one molecule of water for one molecule of the target product]

Comparative Example 4 Synthesis of 4- (4-hydroxyphenyl) benzoic acid-terbium complex

4- (4-Hydroxyphenyl) benzoic acid-sodium salt (0.2 g, 0.93 mmol) was dissolved in water (about 120 mL). To this aqueous solution, a solution of terbium chloride hexahydrate (0.1157 g, 0.31 mmol) dissolved in water (5 mL) was slowly added dropwise. The obtained white precipitate was collected by filtration with a Kiriyama funnel, sufficiently washed with water, and dried to obtain the desired product (yield 63%).
From the following analysis values, it was confirmed to be an object having the above structure.
Elemental analysis (wt%): C: 55.4, H: 3.7 [theoretical value: C: 54.9, H: 3.9 as 3 molecules of water for 1 molecule of the target product]

Example 1 Synthesis of (DPPB) ₃ Eu (Phen) Complex

DPPB (0.30669 g, 1.001 mmol) and Phen (0.06080 g, 0.3373 mmol) were dissolved in ethanol (3.7 mL, about 10% by mass) at room temperature. To this solution, an aqueous solution obtained by dissolving Na ₂ CO ₃ (0.05384 g, 0.508 mmol) in water (5.3 mL, 100 mass%) was added dropwise at room temperature to neutralize. Although it was slightly cloudy before the start of neutralization, it completely dissolved at the end of neutralization.
A solution prepared by dissolving EuCl ₃ .6H ₂ O (0.12220 g, 0.3335 mmol) in water (2.4 mL, 20 mass%) was added dropwise to the neutralized solution at room temperature. White powder started to precipitate immediately after the dropping. This was filtered and dried under reduced pressure at 90 ° C. for 12 hours to obtain 0.359 g of the desired product (yield: 86.2%).
When the solid state was irradiated with a simple UV lamp (365 nm or 254 nm), red light emission characteristic of Eu was observed.
This crystal was confirmed to be a (DPPB) ₃ Eu (Phen) complex having the above structure from the following analytical values.
Elemental analysis (wt%): C: 66.1, H: 4.0, N: 1.9 [theoretical value: C: 66.3, H: 4.2, N: 2.2]

Example 2 Synthesis of (DPPB) ₂ Eu (TTA) (Phen) Complex

DPPB (0.61250 g, 1.999 mmol) and Phen (0.18151 g, 1.007 mmol) were dissolved in ethanol (10 mL, about 10% by mass) at room temperature. To this solution, a solution prepared by dissolving NaOH: 0.12790 g (3.198 mmol) in water (5.2 mL, 40 mass%) was added dropwise at room temperature. Subsequently, TTA (0.22210 g, 1.000 mmol) was added to the obtained solution and dissolved at room temperature. After confirming that the solution was neutral at that time, EuCl ₃ .6H ₂ O (0. A solution prepared by dissolving 36730 g (1.002 mmol) in water (3.7 mL, 10 mass%) was further added dropwise at room temperature. After dropping, white powder started to precipitate in about 15 seconds. This was filtered and dried under reduced pressure at 90 ° C. for 3 hours to obtain 0.949 g of the desired product (yield: 81.5%).
When the solid state was irradiated with a simple UV lamp (365 nm or 254 nm), red light emission characteristic of Eu was observed.
This crystal was confirmed to be a (DPPB) ₂ Eu (TTA) (Phen) complex having the above structure from the following analytical values.
Elemental analysis (wt%): C: 61.0, H: 3.5, N: 2.3 [theoretical values: C: 59.8, H: 3.6, N: 2.4]

Example 3 Synthesis of (DPPB) Eu (TTA) ₂ (Phen) Complex

DPPB (0.30644 g, 1.000 mmol) and Phen (0.17962 g, 0.997 mmol) were dissolved in ethanol (10 mL, about 10% by mass) at room temperature. A solution prepared by dissolving NaOH (0.12753 g, 3.188 mmol) in water (5.2 mL, 40 mass%) was added dropwise to this solution at room temperature. Subsequently, TTA (0.44681 g, 2.011 mmol) was added to the obtained solution and dissolved at room temperature. After confirming that the solution was neutral at that time, EuCl ₃ .6H ₂ O (0. A solution prepared by dissolving 36900 g (1.007 mmol) in water (3.7 mL, 10 mass%) was added dropwise at room temperature. After dropping, white powder started to precipitate in about 15 seconds. This was filtered and dried under reduced pressure at 90 ° C. for 3 hours to obtain 0.666 g of the desired product (yield: 61.7%).
When the solid state was irradiated with a simple UV lamp (365 nm or 254 nm), red light emission characteristic of Eu was observed.
This crystal was confirmed to be a (DPPB) Eu (TTA) ₂ (Phen) complex having the above structure from the following analytical values.
Elemental analysis (wt%): C: 57.6, H: 3.2, N: 2.7 [theoretical value: C: 52.3, H: 2.8, N: 2.6]

Example 4 Synthesis of (DPPB) Eu (TTA) ₂ Complex

DPPB (0.30570 g, 0.998 mmol) was dissolved in ethanol (7.5 mL, about 10% by mass). To this solution, a solution of Na ₂ CO ₃ (0.15950 g, 1.505 mmol) dissolved in water (6.4 mL, 40 mass%) was added dropwise at room temperature. Subsequently, TTA (0.44446 g, 2.000 mmol) was added to and dissolved in the obtained solution. After confirming that the solution was neutral at that time, EuCl ₃ .6H ₂ O (0.36712 g, A solution prepared by dissolving 1.002 mmol) in water (3.7 mL, 10% by mass) was added dropwise at room temperature. A yellowish white powder started to deposit immediately after the dropping. This was filtered and dried under reduced pressure at 90 ° C. for 3 hours to obtain 0.777 g of the desired product (yield: 86.4%).
When a simple UV lamp (365 nm) was irradiated to the solid state, red light characteristic of Eu was observed.
This crystal was confirmed to be a (DPPB) Eu (TTA) ₂ complex having the above structure from the following analytical values.
Elemental analysis (wt%): C: 45.5, H: 2.6 [theoretical value: C: 46.7, H: 2.5]

Example 5 Synthesis of (DPPB) ₂ Eu (TTA) Complex

DPPB (0.61051 g, 1.993 mmol) was dissolved in ethanol (8.5 mL, about 10% by mass). To this solution, a solution of Na ₂ CO ₃ (0.15937 g, 1.504 mmol) dissolved in water (6.4 mL, 40 mass%) was added dropwise at room temperature. Subsequently, TTA (0.22266 g, 1.002 mmol) was added to the obtained solution and dissolved, and after confirming that it was neutral at that time, EuCl ₃ .6H ₂ O (0.36631 g, 0.999 mmol) in water (3.7 mL, 10% by mass) was added dropwise at room temperature. White powder started to precipitate immediately after the dropping. This was filtered and dried under reduced pressure at 90 ° C. for 3 hours to obtain 0.911 g of the desired product (yield: 92.6%).
When a simple UV lamp (365 nm) was irradiated to the solid state, red light characteristic of Eu was observed.
This crystal was confirmed to be a (DPPB) ₂ Eu (TTA) complex having the above structure from the following analytical values.
Elemental analysis (wt%): C: 55.4, H: 3.3 [theoretical value: C: 56.2, H: 3.3]

Example 6 Synthesis of (DPPB) ₃ Tb (Phen) Complex

DPPB (0.30542 g, 1 mmol) and Phen (0.06019 g, 0.33 mmol) were dissolved in ethanol (3.7 mL, about 10% by mass) at room temperature. A solution prepared by dissolving Na ₂ CO ₃ (0.05340 g, 0.508 mmol) in water (4.2 mL, 100% by mass) was added dropwise to this solution at room temperature to neutralize it. To the neutralized solution, a solution obtained by dissolving TbCl ₃ .6H ₂ O (0.12622 g, 0.33 mmol) in water (2.4 mL, 20 mass%) was added dropwise at room temperature. White powder started to precipitate immediately after the dropping. This was filtered and dried under reduced pressure at 90 ° C. for 3 hours to obtain 0.379 g of the desired product (yield: 89.2%).
When a simple UV lamp (365 nm or 254 nm) was irradiated to the solid state, green light emission characteristic of Tb was observed.
This crystal was confirmed to be a (DPPB) ₃ Tb (Phen) complex having the above structure from the following analytical values.
Elemental analysis (wt%): C: 64.5, H: 3.9, N: 1.9 [theoretical values: C: 65.9, H: 4.2, N: 2.2]

Example 7 Synthesis of (DPPB) ₂ Tb (TTA) (Phen) Complex

DPPB (0.61220 g, 1.999 mmol) and Phen (0.18012 g, 0.999 mmol) were dissolved in ethanol (10 mL, about 10% by mass) at room temperature. To this solution, a solution of NaOH (0.12705 g, 3.176 mmol) dissolved in water (5.2 mL, 40 mass%) was added dropwise at room temperature. Subsequently, TTA (0.2218 g, 0.998 mmol) was added to the obtained solution and dissolved at room temperature. After confirming that the solution was neutral at that time, TbCl ₃ .6H ₂ O (0. A solution prepared by dissolving 37513 g (1.005 mmol) in water (3.8 mL, 10 mass%) was added dropwise at room temperature. After dropping, white powder started to precipitate in about 15 seconds. This was filtered and dried under reduced pressure at 90 ° C. for 3 hours to obtain 0.898 g of the desired product (yield: 76.7%).
When a simple UV lamp (365 nm or 254 nm) was irradiated to the solid state, green light emission characteristic of Tb was observed.
This crystal was confirmed to be a (DPPB) ₂ Tb (TTA) (Phen) complex having the above structure from the following analytical values.
Elemental analysis (wt%): C: 63.2, H: 3.8, N: 2.3 [theoretical value: C: 59.4, H: 3.6, N: 2.4]

Example 8 Synthesis of (DPPB) Tb (TTA) ₂ (Phen) Complex

DPPB (0.30603 g, 0.999 mmol) and Phen (0.18053 g, 1.002 mmol) were dissolved in ethanol (10 mL, about 10% by mass) at room temperature. A solution prepared by dissolving NaOH (0.12759 g, 3.189 mmol) in water (5.2 mL, 40% by mass) was added dropwise to this solution at room temperature. Subsequently, TTA (0.44698 g, 2.012 mmol) was added to the obtained solution to dissolve it, and after confirming that it was neutral at that time, TbCl ₃ .6H ₂ O (0.37523 g, A solution prepared by dissolving 1.005 mmol) in water (3.8 mL, 10 mass%) was added dropwise at room temperature. After dropping, white powder started to precipitate in about 15 seconds. This was filtered and dried under reduced pressure at 90 ° C. for 3 hours to obtain 0.578 g of the desired product (yield: 53.2%).
When a simple UV lamp (365 nm or 254 nm) was irradiated to the solid state, green light emission characteristic of Tb was observed.
This crystal was confirmed to be a (DPPB) Tb (TTA) ₂ (Phen) complex having the above structure from the following analytical values.
Elemental analysis (wt%): C: 58.7, H: 3.4, N: 2.7 [theoretical values: C: 51.9, H2.8, N: 2.6]

Example 9 Synthesis of (DPPB) ₂ Tb (TTA) Complex

DPPB (0.61055 g, 1.993 mmol) was dissolved in ethanol (8.5 mL, about 10% by mass). A solution prepared by dissolving Na ₂ CO ₃ (0.15963 g, 1.506 mmol) in water (6.4 mL, 40% by mass) was added dropwise to this solution at room temperature. Subsequently, TTA (0.22204 g, 0.999 mmol) was added to the obtained solution and dissolved at room temperature. After confirming that the solution was neutral at that time, TbCl ₃ .6H ₂ O (0. A solution prepared by dissolving 37735 g (1.011 mmol) in water (3.8 mL, 10 mass%) was added dropwise at room temperature. White powder started to precipitate immediately after the dropping. This was filtered and dried under reduced pressure at 90 ° C. for 3 hours to obtain 0.958 g of the desired product (yield: 96.6%).
When a simple UV lamp (365 nm or 254 nm) was irradiated to the solid state, green light emission characteristic of Tb was slightly observed.
This crystal was confirmed to be a (DPPB) ₂ Tb (TTA) complex having the above structure from the following analytical values.
Elemental analysis (wt%): C: 55.2, H: 3.2 [theoretical value: C: 55.8, H3.3]

[Example 10] Solubility test 5 mg of the complexes synthesized in Examples 1 to 9 and Comparative Examples 3 and 4 were added to 100 mg of tetrahydrofuran (THF), respectively, and the solubility was confirmed by applying ultrasonic waves at 25 ° C. The results are shown in Table 1. The degree of solubility was classified according to the following criteria.
A: Complete dissolution X: There is a suspension at 60 ° C. and does not dissolve (light emission in solid, but the filtrate does not emit light when filtered)

  As shown in Table 1, it can be seen that the carboxylic acid rare earth complexes obtained in Comparative Examples 3 and 4 do not dissolve in THF at all even when heated. On the other hand, it can be seen that the rare earth metal complexes having 1,3-diketone ligand and / or phenanthroline ligand obtained in Examples 1 to 9 are soluble in organic solvents.

[Example 11] Luminescence test 5 mg of the complex synthesized in Examples 1 to 9 was added to 100 mg of THF, and a solution dissolved by applying ultrasonic waves at 25 ° C was taken with a pipette and dropped onto a filter paper. After drying at room temperature, a UV lamp (365 nm or 254 nm) was irradiated, and the luminescence level was visually classified into the following order. The results are shown in Table 2.
Bright and strong emission: ◎, moderate emission: ○, slight emission: △

[Example 12] Results of sublimation (evaporation) test and emission intensity test Each of the complexes obtained in Examples 2, 3 and 4 and Comparative Examples 1 to 4 was put in an appropriate amount (up to about half) in a crucible, and a turbo molecular pump was used. After high vacuum decompression (0.4 to 0.6 mPa), voltage was applied to the filament under the crucible and heated. A quartz substrate was used as the vapor deposition substrate, and the vapor deposition rate was measured with a quartz resonator.
Each complex started from 10 A, and when the deposition rate was insufficient, the current amount was increased by 2 A every 2 minutes, and current was passed until the deposition was finally stopped. When deposition starts, deposition on the quartz substrate starts at a deposition rate of about 0.02 nm / sec, stabilizes at about 0.3-0.5 nm / sec, and deposits up to a maximum thickness of 200 nm (measured about 100 nm). The vapor deposition operation was stopped. The obtained thin film was subjected to fluorescence spectrum measurement (excitation wavelength: 370 nm) using an organic EL quantum yield measurement device (fluorescence spectrum measurement device, C9920-01, manufactured by HAMAMATSU).
For comparison, Alq ₃ represented by the following formula, which is a typical low-molecular light emitting material, was also measured. The results are shown in Table 3.

As shown in Table 3, it can be seen that the rare earth metal complexes having only the carboxylic acid ligands synthesized in Comparative Examples 1 to 4 are decomposed only and no film is formed even when the current is increased to 15 [A]. On the other hand, the rare earth metal complex obtained by coordinating the 1,3-diketone ligand or the 1,3-diketone ligand and the phenanthroline ligand obtained in Examples 2, 3, and 4 is 17 to 18 [A]. A film having a thickness of 60 nm or more was formed, and red-orange light emission of 615 to 616 nm was confirmed.

Claims (7)

A carboxylic acid-diketone composite rare earth metal complex represented by the formula ( 5 ):

Wherein, R ³ and R ⁴ are each independently an alkyl group having a carbon number of 1 to 10, halogenoalkyl group having 1 to 10 carbon atoms, an aryl group which may be substituted with Z, are substituted with Z Represents an optionally substituted heterocyclic group or an aralkyl group optionally substituted with Z. Q represents an oxygen atom, but may not be present.
R ⁵ , R ⁶ and R ⁷ are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkoxycarbonyl having 1 to 10 carbon atoms. A nitro group, a phenyl group optionally substituted with Z, a naphthyl group optionally substituted with Z, a biphenyl group optionally substituted with Z, or an anthryl group optionally substituted with Z .
Z is a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 10 carbon atoms, alkoxycarbonyl group having 1 to 10 carbon atoms, a full Eniru group or a naphthyl group.
M represents a trivalent rare earth metal. B represents a nitrogen-containing heterocyclic compound optionally substituted with Z (Z is the same as described above).
r, s, and t represent an integer of 1 to 4, n ′ represents an integer of 1 to 3, and m ′ represents an integer of 0 to 3. ] R ³ and R ⁴ are each independently an alkyl group having 1 to 10 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, a phenyl group which may be substituted with Z, or a substituent with Z. Represents a good thienyl group, Z represents an alkyl group having 1 to 10 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms or a halogenoalkoxy group having 1 to 10 carbon atoms,
Wherein R ^5, R ⁶ and R ⁷ are all hydrogen atoms, the r, s and t are all 1, not the Q is present, the B is claim 1, wherein Ru good phenanthroline der optionally substituted by Z Carboxylic acid-diketone composite rare earth metal complex. The nitrogen-containing heterocyclic compound is 1,10-phenanthroline der Ru claim 1 or 2 carboxylic acid described - diketone complex rare earth metal complexes. Wherein R ³ is a carboxylic acid according to any one of thiophen-2-yl group der Ru claims 1-3 - diketone complex rare earth metal complexes. Wherein R ⁴ is a carboxylic acid of any one of claims 1-4 a trifluoromethyl group - diketone complex rare earth metal complexes. The carboxylic acid-diketone composite rare earth metal complex according to any one of claims 1 to 5, wherein the rare earth metal is europium (Eu) or terbium (Tb) . A light emitting material comprising the rare earth metal complex according to claim 1 .