JP2022146969A - Rare earth complex with phenanthroline ligand - Google Patents

Abstract

To provide a rare earth complex which has high light emission intensity.SOLUTION: The invention employs a rare earth complex represented by general formula (1). (In the formula, X represents a hydrogen atom, methyl group or phenyl group, where multiple occurrences of X can be identical or different, provided that not all of them are hydrogen atoms simultaneously; W represents a C1-3 fluoroalkyl group, tert-butyl group, furanyl group, thienyl group or phenyl group, where multiple occurrences of W can be identical or different; and Ln represents a rare earth metal atom.)SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a rare earth complex with high emission intensity.

Optoelectronics such as optical communication and displays, and the energy industry such as solar cells are the core technologies of the next generation. Various inorganic glass materials, ceramic materials, laser materials, organic low-molecular-weight light-emitting materials, wavelength conversion materials, etc. used in these technologies have been created. It is

A wavelength conversion material is a material that absorbs light of a specific wavelength and emits light of another wavelength, and can be used as an optical material by adding it to a resin material.

Rare earth complexes having β-diketonato ligands have been reported as such wavelength conversion materials (eg, Non-Patent Document 1). These rare earth complexes can absorb light in the short wavelength range such as ultraviolet light and emit visible light in the longer wavelength range. It is expected that a light-emitting device with luminescent color can be realized. However, current wavelength conversion materials have low emission intensity, and further improvement in intensity has been desired.

Journal of Inorganic and Nuclear Chemistry, Vol. 30, No. 5, p. 1275 (1968)

An object of the present invention is to provide a rare earth complex with high emission intensity.

Means for Solving the Problems As a result of earnest studies in order to solve the above problems, the present inventors have found that a rare earth complex into which a specific ligand is introduced exhibits strong luminescence, and have completed the present invention.

That is, the gist of the present invention is
[1] A rare earth complex represented by the general formula (1) (hereinafter also referred to as a rare earth complex (1));

(In the formula, X represents a hydrogen atom, a methyl group or a phenyl group. A plurality of X may be the same or different. However, all X cannot be a hydrogen atom at the same time. W has 1 carbon atom represents a fluoroalkyl group, a tert-butyl group, a furyl group, a thienyl group, or a phenyl group from 1 to 3. A plurality of W may be the same or different, and Ln represents a rare earth metal atom.)

[2] The rare earth complex according to [1] above, wherein W is a trifluoromethyl group;
[3] The rare earth complex according to [1] or [2] above, wherein Ln is a europium atom;
[4] Any one of [1] to [3], wherein the general formula (1) is a rare earth complex represented by any one of the following formulas (1-1) to (1-3) A rare earth complex according to;

[5] An optical material containing the rare earth complex according to any one of [1] to [4];
Regarding.

The rare earth complex of the present invention serves as an excellent wavelength conversion material having high emission intensity.

1 is an emission spectrum of the rare earth complex (1-1) of the present invention obtained in Example 1. FIG. 4 is an emission spectrum of the rare earth complex (1-2) of the present invention obtained in Example 2. FIG. 3 is an emission spectrum of the rare earth complex (1-3) of the present invention obtained in Example 3. FIG.

Definitions of W, Ln, and X in the general formula (1) of the present invention are explained below.

The fluoroalkyl group having 1 to 3 carbon atoms represented by W in the general formula (1) may be linear or branched, trifluoromethyl group, difluoromethyl group, perfluoroethyl group, 2,2, 2-trifluoroethyl group, 1,1-difluoroethyl group, 2,2-difluoroethyl group, perfluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, 2,2,3,3- tetrafluoropropyl group, 3,3,3-trifluoropropyl group, 1,1-difluoropropyl group, 1,1,1,2,3,3,3-hexafluoro-2-propyl group, 2,2, A 2-trifluoro-1-(trifluoromethyl)ethyl group and the like can be exemplified. A trifluoromethyl group is preferred in that raw materials are readily available.

The rare earth metal atoms represented by Ln in the general formula (1) include scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. of rare earth atoms. Ln in the general formula (1) is preferably a samarium atom, a europium atom, a terbium atom, or a gadolinium atom from the viewpoint of ease of synthesis, and more preferably a europium atom from the viewpoint of having suitable optical properties as an optical functional material.

Specific examples of the rare earth complex (1) include rare earth complexes represented by the following formulas (1-1) to (1-10). The present invention is not limited to these.

As the rare earth complex (1), a compound represented by formula (1-1), (1-2) or (1-3) is preferable because it has optical properties suitable for an optical functional material.

Next, the method for producing rare earth complex (1) (hereinafter referred to as the production method of the present invention) will be described.

As the production method of the present invention, a diketonato complex represented by the following general formula (3) (hereinafter referred to as a diketonato complex (3)) and a substituted phenanthroline represented by the general formula (2) (hereinafter referred to as a phenanthroline ligand ( 2), and a production method characterized by reacting .

(Wherein, W, Ln and X have the same meanings as W, Ln and X in the general formula (1). Q represents a coordination molecule. m represents an integer of 0 to 3.)
In the production method of the present invention, the definitions and specific examples of X, W and Ln are the same as those of X, W and Ln in the general formula (1). )

In the production method of the present invention, specific examples of the coordination molecule represented by Q include water, heavy water, tetrahydrofuran, pyridine, imidazole, acetone, methanol, ethanol, propanol, 1-methylethyl alcohol, acetonitrile and Nitriles such as propionitrile; amines such as ammonia, diethylamine and triethylamine; ethers such as dimethyl ether, diethyl ether and tetrahydrofuran; preferable.

m of the diketonato complex (3) is preferably 2 from the viewpoint of ease of synthesis.

The diketonato complex (3) used in the production method of the present invention is obtained by the method described in Reference Example 1 described later or by the method described in Journal of the American Chemical Society, Vol. 87, pp. 5254-5256, 1965. be able to.

Specific examples of the diketonato complex (3) used in the production method of the present invention include tris[4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionato]europium (III), tris(4,4,4-trifluoro-1-phenyl-1,3-butanedionato)europium(III), tris[4,4,5,5,6,6,6-heptafluoro-1-(2- thienyl)-1,3-hexanedionato]europium (III), tris(4,4,5,5,6,6,6-heptafluoro-1-phenyl-1,3-hexanedionato)europium (III) ), tris[1,3-di-(2-thienyl)-1,3-propanedionato]europium (III), tris(1,3-diphenyl-1,3-propanedionato)europium (III), tris[1-phenyl-3-(2-thienyl)-1,3-propanedionato]europium (III), tris[4,4,4-trifluoro-1-(3-thienyl)-1,3- butanedionato]europium (III), tris[4,4,5,5,6,6,6-heptafluoro-1-(3-thienyl)-1,3-hexanedionato]europium (III), tris[1 -(2-thienyl)-3-(3-thienyl)-1,3-propanedionato]europium (III), tris[1-phenyl-3-(3-thienyl)-1,3-propanedionato] Europium (III) or hydrates thereof can be exemplified.

The phenanthroline ligand (2) in the production method of the present invention includes 4-methyl-1,10-phenanthroline, 5-methyl-1,10-phenanthroline, 5,6-dimethyl-1,10-phenanthroline, 4, 7-dimethyl-1,10-phenanthroline, 4,5,6,7-tetramethyl-1,10-phenanthroline, 4-phenyl-1,10-phenanthroline, 5-phenyl-1,10-phenanthroline, 5,6 -diphenyl-1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, 4,5,6,7-tetraphenyl-1,10-phenanthroline. 4-methyl-1,10-phenanthroline, 5,6-dimethyl-1,10-phenanthroline, or 4,7-dimethyl-1,10-phenanthroline is preferred in that raw materials are readily available. The present invention is not limited to these. As the phenanthroline ligand (2) used in the production method of the present invention, one synthesized by a known synthesis method may be used, or a commercially available product may be used.

The production method of the present invention is preferably carried out in a solvent because the yield of the rare earth complex (1) is good. There are no particular restrictions on the types of solvents that can be used as long as they do not inhibit the reaction. Examples of usable solvents include halogenated hydrocarbons such as dichloromethane, chloroform and chlorobenzene; alcohols such as methanol, ethanol, propanol and isopropyl alcohol; esters such as methyl acetate, ethyl acetate, butyl acetate and isoamyl acetate. ; glycol ethers such as ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether; ethers such as diethyl ether, tert-butyl methyl ether, glyme, diglyme, triglyme, tetrahydrofuran, cyclopentyl methyl ether; tert-butyl Ketones such as methyl ketone, isobutyl methyl ketone, ethyl butyl ketone, dipropyl ketone, diisobutyl ketone, cyclohexanone, and acetone; hydrocarbons such as hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, heptane, octane, benzene, toluene, and xylene or water. These solvents may be used singly or as a mixture of two or more at any ratio. Dichloromethane, chloroform, methylcyclohexane, acetone, methanol, ethanol, or water are preferable because the reaction yield of the rare earth complex (1) is good.

The molar equivalents of the diketonato complex (3) and the phenanthroline ligand (2) in the production method of the present invention will be explained. It is preferable to use 0.25 to 2.5 mol of phenanthroline ligand (2) per 1 mol of diketonato complex (3), and 0.5 to 2.0 mol of phenanthroline ligand (2) is used. is more preferred.

In the production method of the present invention, the reaction temperature and reaction time are not particularly limited, and those skilled in the art can use general conditions for producing metal complexes. As a specific example, the rare earth complex (1) is produced in good yield by reacting at a reaction temperature appropriately selected from the range of −80° C. to 120° C. for a reaction time appropriately selected from the range of 1 minute to 120 hours. can be done.

The rare earth complex (1) produced by the production method of the present invention can be purified by appropriately selecting and using a general purification method for purifying metal complexes by those skilled in the art. Specific purification methods include concentration, filtration, extraction, centrifugation, decantation, sublimation, crystallization, reprecipitation, column chromatography and the like.

Since diketonato complex (3) can undergo tautomerization to form diketonato complex (3i), both diketonato complex (3) and diketonato complex (3i) are included. In the specification, these isomers are expressed as general formula (3). Similarly, the rare earth complex (1) of the present invention includes the rare earth complex (1i) which is a tautomer, and these isomers are expressed as general formula (1) in this specification.

The rare earth complex (1) of the present invention has a high emission intensity. Therefore, the material containing the rare earth complex (1) is useful as a strongly luminescent optical material. It is suitably used for the wavelength conversion material used.

In addition, the rare earth complex (1) of the present invention can be used as an optical material containing one or more selected from the group consisting of resin materials, inorganic glasses, and organic low-molecular-weight materials. is high, it is particularly preferable to use an optical material containing a resin material. The resin material includes polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, polyisopropyl methacrylate, polybutyl methacrylate, polysec-butyl methacrylate, polyisobutyl methacrylate, poly tert-butyl methacrylate, fluorine-containing polymethyl methacrylate, fluorine-containing poly Polymethacrylates such as ethyl methacrylate, fluorine-containing polypropyl methacrylate, fluorine-containing polyisopropyl methacrylate, fluorine-containing polybutyl methacrylate, fluorine-containing polysec-butyl methacrylate, fluorine-containing polyisobutyl methacrylate, and fluorine-containing polytert-butyl methacrylate, polymethyl acrylate , polyethyl acrylate, polypropyl acrylate, polyisopropyl acrylate, polybutyl acrylate, polysec-butyl acrylate, polyisobutyl acrylate, polytert-butyl acrylate, fluorine-containing polymethyl acrylate, fluorine-containing polyethyl acrylate, fluorine-containing polypropyl acrylate , fluorine-containing polyisopropyl acrylate, fluorine-containing polybutyl acrylate, fluorine-containing polysec-butyl acrylate, fluorine-containing polyisobutyl acrylate, fluorine-containing polytert-butyl acrylate, polystyrene, polyethylene, polypropylene, polybutene, fluorine-containing polyethylene Polyolefins such as , fluorine-containing polypropylene, fluorine-containing polybutene, polyvinyl ether, fluorine-containing polyvinyl ether, polyvinyl acetate, polyvinyl chloride, or copolymers thereof; cellulose; polyacetal; polyester; polycarbonate; epoxy resin; polyamide resin; resin; polyurethane; Nafion; petroleum resin; rosin;

Among them, polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, polyisopropyl methacrylate, polybutyl methacrylate, polysec-butyl methacrylate, polyisobutyl methacrylate, poly tert-butyl methacrylate, polymethyl acrylate, polyethyl acrylate, polypropyl acrylate , polyisopropyl acrylate, polybutyl acrylate, polysec-butyl acrylate, polyisobutyl acrylate, polytert-butyl acrylate, polyethylene, polystyrene, polyvinyl acetate, or copolymers thereof; epoxy resin; polyimide resin; silicone resin, etc. Preferably, polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polyethyl acrylate, polypropyl acrylate, polybutyl acrylate, polyethylene, polystyrene, polyvinyl acetate, or copolymers thereof; epoxy Resin; polyimide resin; and silicone resin are more preferable. These may be used alone or in combination of two or more.

The content of the rare earth complex (1) in the optical material containing the rare earth complex (1) of the present invention and a resin material is preferably in the range of 0.001 to 99% by weight, more preferably 0.01 to 50% by weight. % range.

As the above inorganic glass, those commonly used by those skilled in the art may be used, and examples thereof include soda glass, lead glass, borosilicate glass, phosphate glass, and the like.

As the above-mentioned organic low-molecular-weight materials, those commonly used by those skilled in the art may be used. , and hydrocarbons such as paraffin.

As a method of obtaining an optical material containing the rare earth complex (1) of the present invention, there is a method of using the rare earth complex (1) alone as an optical material, a method of using the rare earth complex (1) alone as an optical material, a method of using the rare earth complex (1) as a resin material, an inorganic glass, and an organic low A method of making an optical material by incorporating it in a material containing one or more selected from the group consisting of materials, and an optical material by mixing a monomer corresponding to the polymerization raw material of the resin material with the rare earth complex (1) and polymerizing the mixture. and a method of dissolving or dispersing the rare earth complex (1) in a solvent to form an optical material.

When the rare earth complex (1) of the present invention is dissolved or dispersed in a solvent to form an optical material, usable solvents include, for example, halogenated hydrocarbons such as dichloromethane, chloroform and chlorobenzene; methanol, ethanol, propanol, alcohols such as isopropyl alcohol; esters such as ethyl acetate, butyl acetate and isoamyl acetate; glycol ethers such as ethylene glycol monoethyl ether, ethylene glycol monomethyl ether and ethylene glycol monobutyl ether; diethyl ether, tert-butyl methyl ether, Ethers such as glyme, diglyme, triglyme, and tetrahydrofuran; ketones such as tert-butyl methyl ketone, isobutyl methyl ketone, ethyl butyl ketone, dipropyl ketone, diisobutyl ketone, cyclohexanone, and acetone; hexane, cyclohexane, methylcyclohexane, ethylcyclohexane , heptane, octane, benzene, toluene, and xylene; or water. Among them, halogenated hydrocarbons, alcohols, esters, glycol ethers, ethers, ketones or hydrocarbons are preferred. These solvents can be used alone or in combination of two or more at any ratio.

EXAMPLES The present invention will be described in more detail below with reference to examples, comparative examples, and evaluation results, but the present invention should not be construed as being limited thereto.

The following analytical methods were used for identification of the rare earth complex (1).

BRUKER ULTRASHIELD PLUS AVANCE III (376 MHz) or ASCEND AVANCE III HD (376 MHz) was used for the measurement of ¹⁹ F-NMR spectrum. ¹⁹ F-NMR spectra were measured using deuterated chloroform (CDCl ₃ ) or deuterated acetone (Acetone-d ₆ ) as a measurement solvent.

The mass spectrum was measured using waters 2695-micromass ZQ4000 manufactured by Waters, electrospray was used as the ionization method, and methanol was used as the solvent.

Commercially available reagents were used.

In this specification, hfa represents a hexafluoroacetylacetonato ligand.
(Comparative example 1)

Pure water (100 mL) was added to europium acetate n-hydrate (8.00 g, 21.4 mmol as 2.5 hydrate), and the mixture was stirred at room temperature for 10 minutes. Hexafluoroacetylacetone (16.7 g, 80.2 mmol) was added dropwise to the reaction mixture, and the mixture was stirred at 50°C for 3 hours. The resulting white suspension was filtered, and the resulting white solid was washed with water (200 mL) and toluene (200 mL) to give diaquatris(hexafluoroacetylacetonato)europium (III) (1-a). was obtained as a white solid (11.6 g yield, 68% yield using 21.4 mmol of europium acetate dipentahydrate). ¹⁹ F-NMR (376 MHz, Acetone-d ₆ ), δ (ppm): −81.2 (brs). ESI-MS (m/z): 566.8 [M-hfa] ⁺ .
(Example 1)

Methanol (3.0 mL) was added to diaquatris(hexafluoroacetylacetonato) europium (III) (240 mg, 300 μmol) and 5,6-dimethyl-1,10-phenanthroline (62.5 mg, 300 μmol), and the mixture was stirred at room temperature for 3 hours. Stirred. Thereafter, the reaction solution was concentrated under reduced pressure and recrystallized with methanol to give white powder of tris(hexafluoroacetylacetonato)(5,6-dimethyl-1,10-phenanthroline)europium (III) (1-1). (Yield 111 mg, Yield 38%). ¹⁹ F-NMR (376 Hz, CDCl ₃ ) δ (ppm): −79.3. ESI-MS: (m/z) 720.1 [M-hfa] ⁺ .
(Example 2)

Methanol (3.0 mL) was added to diaquatris(hexafluoroacetylacetonato) europium (III) (242 mg, 300 mmol) and 4,7-dimethyl-1,10-phenanthroline (62.6 mg, 300 mmol), and the mixture was stirred at room temperature for 2 hours. Stirred. Thereafter, the reaction solution was concentrated under reduced pressure and recrystallized with methanol to give (4,7-dimethyl-1,10-phenanthroline)tris(hexafluoroacetylacetonato)europium (III) (1-2) as a white solid. (Yield 111 mg, Yield 40%). ¹⁹ F-NMR (376 Hz, CDCl ₃ ) δ (ppm): −79.2. ESI-MS: (m/z) 772.3 [M-hfa] ⁺ .
(Reference example 1)

Ethanol (41 mL) and an aqueous solution (54 mL) of europium chloride hexahydrate (2.00 g, 5.46 mmol) were added to 1,3-diphenyl-1,3-butanedione (3.68 g, 16.4 mmol). A 1 M sodium hydroxide aqueous solution (16.0 mL, 16.0 mmol) was added to the reaction mixture, and the mixture was stirred at room temperature for 1 hour. The resulting solid was collected by filtration, washed with water and ethanol, and dried by heating at 50°C under reduced pressure. Acetone is added to the obtained crude product, insoluble matter is removed by filtration, and the filtrate is concentrated to obtain a yellow solid of diaquatris(1,3-diphenyl-1,3-butanedionato)europium (III). (yield 2.76 g, yield 59%). ESI-MS (m/z): 634.0 [M-(1,3-diphenyl-1,3-butanedionato)] ⁺ .
(Example 3)

Diaquatris(1,3-diphenyl-1,3-propanedionato)europium(III) (265 mg, 304 mmol) obtained in Reference Example 1 and 4-methyl-1,10-phenanthroline (58.9 mg, 304 mmol) were added with methanol. (3.0 mL) was added and stirred at room temperature for 3 hours. The reaction solution is filtered, and the filtrate is recrystallized with chloroform to obtain (4-methyl-1,10-phenanthroline)tris(1,3-diphenyl-1,3-propanedionato)europium (III) (1- A yellow solid of 1) was obtained (133 mg, 43% yield). ESIMS: (m/z) 1039.0 [M+Na] ^<+ >.
(Evaluation results)
An absolute PL quantum yield measurement device (C11347-01, manufactured by Hamamatsu Photonics) was used to measure the emission spectrum and emission quantum yield.

The measurement results of the emission spectrum of the rare earth complex (1) obtained in Example are shown in FIGS. 1 and 2. FIG. The measurement conditions for the emission spectrum were an excitation wavelength of 465 nm. Emissions at about 593 nm, 615 nm, 653 nm and 699 nm characteristic of Eu(III) complexes were observed.

Table 1 shows the measurement results of the emission quantum yields of the rare earth complexes obtained in Examples 1 and 3 and Comparative Example 1 at an excitation wavelength of 465 nm.

As shown in Table 1, the rare earth complex (1) of the present invention exhibits a higher emission quantum yield than the compound 1-a of the comparative example, and thus is a material having a high emission intensity.

The rare earth complex (1) of the present invention has a high emission intensity. Therefore, it is useful as a light-emitting material such as a film for solar cells, an agricultural film, an LED phosphor, and a security ink, and a wavelength conversion material used therefor.

Claims (5)

A rare earth complex represented by the general formula (1).

(In the formula, X represents a hydrogen atom, a methyl group or a phenyl group. A plurality of X may be the same or different. However, all X cannot be a hydrogen atom at the same time. W has 1 carbon atom represents a fluoroalkyl group, a tert-butyl group, a furyl group, a thienyl group, or a phenyl group from 1 to 3. A plurality of W may be the same or different, and Ln represents a rare earth metal atom.) 2. The rare earth complex according to claim 1, wherein W is a trifluoromethyl group. 3. The rare earth complex according to claim 1 or 2, wherein Ln is a europium atom. 4. The rare earth complex according to any one of claims 1 to 3, wherein the general formula (1) is represented by any one of the following formulas (1-1) to (1-3).

An optical material comprising the rare earth complex according to claim 1 .

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