JP2001270893A - Highlight fluorescent iridium complex and rapid and simple synthesis of the complex through microwave heating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a novel highlight fluorescent iridium complex and a microwave-heating rapid and simple synthesis of the novel complex, further elucidate the availability of this iridium complex and obtain highlight fluorescent substance showing blue, yellow and red. SOLUTION: This inventor has succeeded for the first time in the rapid and simple synthesis of the novel highlight fluorescent iridium complex in a high-boiling solvent by the microwave heating (24.5 MHz) by using an electronic oven. According to this invention, a novel iridium complex has been synthesized for the first time through the rapid and simple process. The complex is soluble in a variety of media, for example, acetonitrile, alcohols, water, and the like, and stable for a long period of time. Further, the complex shows the highlight fluorescence of various colors (blue, yellow and red) in solvents and the fluorescent intensity scarcely changes and a large range of application can be expected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel high-brightness fluorescent iridium complex and its rapid and simple synthesis by microwave heating.

[0002]

2. Description of the Related Art An iridium complex containing a pyridine ring is 25%.
Since synthesis was performed at 0 to 300 ° C. by convection heating by a reflux method or by a heating method by a sealed tube method, a long heating time was required. In these synthetic methods, there were many by-products, the purification process was complicated, and it was extremely difficult to extract a pure substance. So far, trisbipyridyl iridium complexes have been described (Flynn, CM and Demas, J. Am.
N. , J. et al. Am. Chem. Soc. 1974, 96,
1959), but has the drawback of requiring a number of steps for purification and resulting in a very low yield (about 30%). In addition, high-brightness fluorescence was not obtained.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel high-brightness fluorescent iridium complex by rapid and simple synthesis by microwave heating. Another object of the present invention is to clarify the usefulness of the iridium complex and to provide a novel high-luminance blue, yellow, and red phosphor. The present inventors have now used a commercially available microwave oven (500 W) to prepare ethylene glycol (boiling point: 197.6 ° C.), glycerin (boiling point: 290.5 ° C.), 1,2-propanediol (boiling point: 18
7.9 ° C.), 1,3-propanediol (boiling point 213.
5 ° C.), microwave irradiation (24.5 MHz, 500) in a high boiling point solvent (solvent described in Table 1) such as dimethyl sulfoxide (boiling point: 189 ° C.), propylene (boiling point: 240 ° C.).
(W, 10-15 minutes) and reflux. According to this method, a novel single-coordination complex (tris complex [Ir (L ₁ ) ₃ ] X ₃ (L ₁ is 4,7-diphenyl-1,10-phenanthroline, 2,2′-biquinoline, etc.) bidentate ligand according to the anion X is PF ₆ ^-.. Hitoshihyo according to 1) bis _{complex, [Ir (terpy) 2]} X 3
(In these complexes X is PF ₆ ^- anion according to Hitoshihyo 1). Binary mixed coordination complex General formula: [Ir (L ₁ ) ₂ (L ₂ )] X ₃ (L ₁ , L ₂
Is 4,7-diphenyl-1,10-phenanthroline,
Bidentate ligands described in Table 1 such as 2,2′-biquinoline). General formula: [Ir (L ₁ ) ₂ X ₂ ] X, wherein the ligand L ₁ is 4,7-diphenyl-1,10-phenanthroline ligand, 2,2′-biquinoline or the like described in Table 1. The coordinating ligand and monodentate ligand X are Cl ⁻ , Br ⁻ , and I ^{− shown in} Table 1. The anion X is an anion described in Table 1. Triple mixed coordination complex [I
r (L ₁ ) (terpy) X] X ₂ (in this case, L ₁
Is a bidentate ligand described in Table 1 such as a 4,7-diphenyl-1,10-phenanthroline ligand, a 2,2′-biquinoline ligand, and the ligand X is Cl ⁻ , Br ⁻ , I ^{For the} first time, it was possible to produce PF ₆ -an anion shown in Table 1 such as a halogen ligand and an anion ( ^- ) in a simple manner with high yield.

In Table 1, the names and abbreviations of the ligands L ₁ and L ₂ in the complex are shown in the _first and second columns. Of these ligands, terpyridine is a tridentate ligand, and all others are bidentate ligands. The third column shows monodentate ligands (halogen ligands) X. The fourth column shows the anion X and the fifth column shows the solvent S used for rapid and simple synthesis by heating.

EXAMPLES Production of [Ir (L ₁ ) ₃ ] X ₃ Complex A method for producing [Ir (dpphen) ₃ ] (PF ₆ ) ₃ will be described as an example. In a round bottom flask, trivalent hexahalide iridium salt General formula: M ₃ [IrX ₆ ] (H ₂ O), (M =
K, Na, Li and NH ₄ , X = Cl, Br, I) and L ₁ (bidentate ligand: 4,7-diphenyl-1,10-phenanthroline) in a molar ratio of 1: 3 (1 mmol and 3 mmol) and the solvent ethylene glycol (15 ml) is added. Place the round bottom flask containing the suspension in a microwave oven (Figure 1) and attach a reflux tube. A microwave (frequency: 24.5 MHz, 500 W) is irradiated while turning on a microwave oven and flowing nitrogen gas. About 1 minute after the microwave heating, the suspension solution dissolves, and the solution turns reddish brown. Reflux in a nitrogen stream under microwave irradiation for 15 minutes. After stopping the microwave irradiation, the solution is allowed to cool. To the cooled reddish brown solution, add potassium hexafluorophosphate (K
Addition of a saturated aqueous solution of PF ₆ ) produces a yellow precipitate.
The deposited precipitate is captured by suction filtration. The resulting precipitate is dissolved in acetonitrile (10-20 ml) (becomes a yellow solution). Add acetonitrile solution to ether (50m
When l) is added until precipitation occurs, a yellow precipitate precipitates.
The yellow precipitate is collected by suction filtration. Vacuum drying to obtain pure substance. The yield was 91% and the elemental analysis values were in good agreement with the theoretical values.

Example 2: Preparation of [Ir (L ₁ ) ₂ X ₂ ] X complex [Ir (dpphen) ₂ Cl ₂ ] (PF ₆ )
The manufacturing method of is shown. In a round bottom flask, trivalent hexahalide iridium salt, (general formula: M ₃ [IrX ₆ ] (H
₂ O), M = K, Na, Li and NH ₄ , X = Cl,
Br, I) and L ₁ (bidentate ligand: 4,7-diphenyl-)
1,10-phenanthroline) in a 1: 2 molar ratio (1 mmol to 2 mmol) is added and the solvent ethylene glycol (15 ml) is added. Put the round bottom flask containing the suspension in a 500 W microwave oven and attach a reflux tube (Fig. 1). Switch on the microwave oven and supply nitrogen gas while flowing microwave (frequency 24.5 MHz, 5
00W). About 1 minute after microwave heating, the suspension dissolves and the solution turns reddish brown. Reflux in a nitrogen stream under microwave irradiation for 15 minutes. . After stopping the microwave irradiation, the solution is allowed to cool. When a saturated aqueous solution of potassium hexafluorophosphate (KPF ₆ ) is added to the cooled reddish brown solution, a yellow precipitate is formed. The deposited precipitate is captured by suction filtration. The obtained precipitate is washed with acetonitrile (10 to 20).
(yellow solution). Ether (50 ml) is added to the acetonitrile solution until a precipitate forms, and a yellow precipitate precipitates. The yellow precipitate is collected by suction filtration. Vacuum drying to obtain pure substance. The yield was 60%, and the elemental analysis values were in good agreement with the theoretical values.

Example 3 [Ir (L ₁ ) (terpy) X] X
Production of _2- complex [Ir (dmpy) (terpy) Cl]
A method for producing (PF ₆ ) ₂ will be described. In a round bottom flask, trivalent iridium halide hexavalent (general formula: M ₃ [Ir
X ₆ ] (H ₂ O), M = K, Na, Li and NH _4,
X = Cl, Br, I) and a mixture of tridentate ligand: terpyridine in a molar ratio of 1: 1 (1 mmol and 1 mmol) are added, and the solvent ethylene glycol (15 ml) is added.
The round bottom flask containing the suspension is placed in a 500 W microwave oven, and a reflux tube is attached (FIG. 1). Switch on the microwave oven and let the nitrogen gas flow through the microwave (frequency 2
(4.5 MHz, 500 W). About 1 minute after the microwave heating, the suspension solution dissolves, and the solution turns reddish brown.
After refluxing for 5 minutes under microwave irradiation in a nitrogen stream, L ₁ (bidentate ligand: 4,4′-dimethyl-2,2 ′) was added to the solution.
-Bipyridine) is added in a molar ratio of 1: 1 (1 mmol: 1 mmol) to the iridium (III) ion and the reflux is continued for 10 minutes. After the microwave irradiation is stopped, the picture metal is allowed to cool. When a saturated aqueous solution of potassium hexafluorophosphate (KPF ₆ ) is added to the cooled reddish brown solution, a yellow precipitate is formed. The deposited precipitate is captured by suction filtration. The precipitate obtained is dissolved in acetonitrile (10-20 ml) (it becomes a yellow solution). Ether (50 ml) is added to the acetonitrile solution until a precipitate forms, and a yellow precipitate precipitates. The yellow precipitate is collected by suction filtration. Vacuum drying to obtain pure substance. The yield was 60%, and the elemental analysis values were in good agreement with the theoretical values.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a microstructure of a high-brightness fluorescent iridium complex.
The wave heating rapid simple synthesis device is shown. Commercially available microwave oven
And a choke pipe into which a reflux tube was inserted. Round bottom
A trivalent iridium hexachloride (general formula: M
₃[IrX₆] (H₂ O), (M = K, Na, Li and
And NH_4,X = Cl, Br, I) and L₁(Bidentate ligand:
4,7-diphenyl-1,10-phenanthroline)
Mixture in a molar ratio of 1: 3 (1 mmol: 3 mmol)
Of ethylene glycol (15 ml) as a solvent. Hanging
Put the round bottom flask containing the suspension into a 500W microwave oven
And attach a reflux tube to the top. Allow nitrogen gas to flow
Bubble crab. Switch on the microwave oven and
While flowing elementary gas, microwave (frequency 24.5 MH
z). Reddish brown produced by stopping microwave irradiation
After allowing the color solution to cool, the precipitated precipitate is captured by suction filtration.
You. The obtained precipitate is acetonitrile (10 to 20 ml)
(Dissolve in yellow). Add acetonitrile solution to
-Tel (50 ml) was added until precipitation occurred,
The tongue precipitates. The yellow precipitate is collected by suction filtration.
Vacuum drying to obtain pure substance. If necessary, expose the reflux tube
Guard with a metal plate to prevent microwave leakage.
Microwave heating is different from convection heating by the conventional reflux method
Because of night heating due to frictional heat caused by molecular rotation,
High temperature at the bell (molecular heating), extremely high reaction efficiency
It is characteristically high.

[0008] The produced high-intensity fluorescent iridium complex is 2
In the wavelength range from 80 nm to 350 nm, it shows high-intensity absorption mainly due to the ligand in the complex. On the other hand, the fluorescence wavelength of the complex varies in a range of 380 nm to 630 nm depending on the ligand. In particular, [Ir (dmdpphe
n) ₃ ] (PF ₆ ) ₃ complex emits blue fluorescence (λ = 380 n
m), [Ir (dmpy) ₃ ] (PF ₆ ) ₃ emits yellow fluorescence (λ = 525 nm) and [Ir (bqn) ₃ ] (PF
₆ ) ₃ exhibited red fluorescence. The characteristic absorption spectrum and fluorescence spectrum of the high-brightness fluorescent iridium complex are shown as [Ir
(Dpphen) ₃ ] (PF ₆ ) ₃ is shown in FIG.

FIG. 2 shows an iridium trisdiphenylphenanthroline complex ([Ir (dpphen) ₃ ] (P
F ₆ ) ₃ ) Absorption spectrum A (horizontal axis, wavelength λ / nm,
Vertical axis, absorbance) and fluorescence spectrum B (horizontal axis, wavelength λ / n)
m, vertical axis, fluorescence intensity). The absorption spectrum of the complex was measured using a spectrophotometer U-3010 (Hitachi), and the fluorescence spectrum was measured using a spectrofluorometer F-2500 (Hitachi). The maximum absorption wavelength λ _max and the absorption intensity ε ₂₈₂ of [Ir (dpphen) ₃ ] (PF ₆ ) ₃ are 282, respectively.
nm, 1.1 × 10 ⁵ M ⁻¹ cm ⁻¹ . Maximum wavelength of fluorescence at 539 nm, the fluorescence intensity epsilon _1,318 when irradiated with excitation light having a wavelength of 318nm is, 1.8x10 ⁸ M
^-1 cm ^-1 .

[0010] Table 2 shows the yield of the high-brightness fluorescent iridium complex produced by the microwave heating rapid simple synthesis method.
Both the single coordination complex and the mixed coordination complex have a high yield of 60% or more.

The fluorescent intensity of the manufactured high-intensity fluorescent iridium complex was excited by light in a wavelength range of 320 to 350 nm, and the maximum fluorescent intensity was measured. The wavelength of the excitation light is the fluorescence intensity of the complex at the maximum fluorescence wavelength (ε ₁ ) and the absorption intensity at the excitation wavelength (ε
₂ ) was set to a wavelength at which the ratio (ε ₁ / ε ₂ ) became maximum.
High intensity fluorescence of iridium complex ε ₁ / ε ₂ value fluorescent complexes are generally known _{Ru (bpy) 3 (PF 6} ) 3 of epsilon ₁
/ Epsilon shows a larger value than the _binary, high brightness. In particular, Table 3 shows selected examples.

Table 3 shows the excitation wavelength of the single coordination complex, the absorption intensity (ε) at the excitation wavelength, the maximum fluorescence wavelength and the fluorescence intensity (ε ₁ ). Here, the excitation wavelength is the ratio of the fluorescence intensity and the absorption intensity of the complex at the maximum fluorescence wavelength (ε ₁ /
The wavelength at which ε ₂ ) was maximized was set. The fluorescence wavelength of the tris complex and bisterpyridine complex shown in the table is 525-6.
In the range of 30 nm, the highest value of ε ₁ / ε ₂ is 4 times the value of the commonly known fluorescent complex Ru (bpy) ₃ (PF ₆ ) _3.
The luminance is almost doubled.

Table 4 shows examples of the excitation wavelength of each mixed coordination complex, the absorption intensity (ε) at the excitation wavelength, the maximum fluorescence wavelength and the fluorescence intensity (ε ₁ ). Fluorescence wavelength is 380 nm to 62
It covers a wide range of 2 nm. The highest value of ε ₁ / ε ₂ is 2.78 × 10 ⁴ , and Ru (bpy) ₃ (PF ₆ ) ₃
, Which is 28 times the value of the above, indicating high-brightness fluorescence.
Further, the high-brightness fluorescent iridium complex has high stability such that its fluorescence is not lost for a long time (about one year or more).

The high-brightness fluorescent iridium complex can be dissolved in various solvents such as acetonitrile, ethanol, high-boiling solvents (Table 1), water and the like by changing the anion in the complex.

According to the present invention, rapid and simple complex synthesis has been made possible by applying molecular heating by microwave irradiation using a microwave oven. The shortening of the reaction time and the synthesis by molecular heating suppress the formation of by-products due to side reactions and unreacted reactions, and enable the synthesis of the desired high-brightness fluorescent iridium complex in high yield. In addition, these complexes make it possible to produce a high-luminance fluorescent material because the ligand in the complex efficiently absorbs the excitation light and effectively transmits the light to the central iridium metal ion. In addition, by selecting a ligand, it is possible to produce a high-luminance light-emitting material that selectively responds to specific excitation light. in addition,
These complexes are very stable and have extremely high fluorescence intensity (Tables 3 and 4), and have various fluorescence wavelengths (3
(80 nm to 630 nm).

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[Procedure amendment]

[Submission date] June 25, 2000 (2006.2.
5)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Added

[Correction contents]

[Brief description of the drawings]

FIG. 1 shows a microwave heating apparatus (microwave oven with a reflux condenser) for synthesizing an iridium complex. A round bottom flask is charged with a solution of an iridium (III) hexahalide salt and an ethylene glycol solution of a polypyridine ligand, and is irradiated with microwaves in a 500 W microwave oven while passing nitrogen gas (nitrogen bubble →). The outer cylinder of the reflux pipe (reflux pipe →) is cooled by flowing cooling water (cooling water →).

FIG. 2 shows an Ir (dpphen) ₃ complex (Ir (I
II) trisdiphenylphenanthroline complex). A in FIG.
1 shows an absorption spectrum of x10 ^-5 MIr (dpphen) ₃ (PF ₆ ) ₃ . The horizontal axis represents wavelength, and the vertical axis represents absorbance (O.D.
D). FIG. 2B shows 1 × 10 ⁻⁵ MIr (dpph
2 shows the fluorescence spectrum of (en) ₃ (PF ₆ ) ₃ . The horizontal axis represents the wavelength, and the vertical axis represents the photometric value in terms of the fluorescence intensity. 539 nm indicates the wavelength at which the fluorescence intensity is maximum. λ _ex = 318 nm
Shows an excitation wavelength of 318 nm.

[Description of Signs] Ir (dpphen) ₃ (PF ₆ ) ₃ : iridium (I
II) hexafluorophosphate of trisdiphenylphenanthroline complex D. : Abbreviation of Optical Density, indicating absorbance. λ: wavelength nm: nanometer, 10 ⁻⁹ m Intensity: fluorescence intensity λ _ex : excitation wavelength M: molar concentration (mol / l)

Claims (1)

[Claims] 1. A single coordination complex (tris complex, bis complex) tris complex, represented by the general formula: [Ir (L₁)₃] X₃Represented by
Iridium complex, L₁ Represents a bidentate ligand, and 4,7
-Diphenyl-1,10-phenanthroline, 2,9-
Dimethyl-4,7-diphenyl-1,10-phenanth
Loline, 5-phenyl-1,10-phenanthroline,
5-nitro-1,10-phenanthroline, 5-chloro
-1,10-phenanthroline, 4,4'-dimethyl-
2,2'-bipyridine, 4,4'-diphenyl-2,
2'-bipyridine, 2,2'-bipyridine-3,3'-
Diol, 2,2'-bipyridine-4,4'-dicarbo
Acid, 2,2'-biquinoline, 2,2'-biquinoline-
4,4'-dicarboxylic acid. X represents an anion, and PF₆
⁻, BF₄ ⁻, Cl⁻, Br⁻, I⁻, ClO₄ ⁻, S
O₄ ^2-, NO₃ ⁻. Bis complex, a general formula [Ir (ter
py)₂] X₃An iridium complex represented by the formula: terpy
Is a tridentate ligand 2,2 ': 6', 2 "-terpyridine, X
Represents an anion and PF₆ ⁻, BF₄ ⁻, Cl⁻, Br
⁻, I⁻, ClO₄ ⁻, SO₄ ^2-, NO₃ ⁻. Mixed coordination complex (binary coordination complex, ternary coordination complex) Binary coordination complex, general formula: [Ir (L₁)
₂(L₂)] X₃Iridium complex represented by
Child (L₁, L₂) Is 4,7-diphenyl-1,1
0-phenanthroline, 2,9-dimethyl-4,7-di
Phenyl-1,10-phenanthroline, 5-phenyl
-1,10-phenanthroline, 5-nitro-1,10
-Phenanthroline, 5-chloro-1,10-phenan
Toroline, 4,4'-dimethyl-2,2'-bipyridi
4,4'-diphenyl-2,2'-bipyridine,
2,2'-bipyridine-3,3'-diol, 2,2 '
-Bipyridine-4,4'-dicarboxylic acid, 2,2'-bicarboxylic acid
Quinoline, 2,2'-biquinoline-4,4'-dicarbo
Acid. X represents an anion, and PF₆ ⁻, BF₄ ⁻, Cl
⁻, Br⁻, I⁻, ClO₄ ⁻, SO₄ ^2-, N
O₃ ⁻. General formula: [Ir (L₁)₂X₂] Represented by X
Iridium complex, complex is bidentate ligand L₁, Monodentate ligand
X, an anion X and iridium ion.
Bidentate ligand L₁Is 4,7-diphenyl-1,10-phenyl
Nanthroline, 2,9-dimethyl-4,7-diphenyl
-1,10-phenanthroline, 5-phenyl-1,1
0-phenanthroline, 5-nitro-1,10-phena
Enthroline, 5-chloro-1,10-phenanthroli
4,4'-dimethyl-2,2'-bipyridine, 4,
4'-diphenyl-2,2'-bipyridine, 2,2'-
Bipyridine-3,3'-diol, 2,2'-bipyridi
-4,4'-dicarboxylic acid, 2,2'-biquinoline,
2,2'-biquinoline-4,4'-dicarboxylic acid. Single seat
As the ligand X, chloride ion, bromide ion, iodide
Halogen ligand of the ion. PF as anion X₆ ⁻,
BF₄ ⁻, Cl⁻, Br⁻, I⁻, ClO₄ ⁻, SO₄
^2-, NO₃ ⁻. Three-type coordination complex, general formula: [Ir
(L₁) (Terpy) X] X₂Iridium represented by
Complex. terpy is a tridentate terpyridine, L₁age
4,7-diphenyl-1,10-phenanthroli
2,9-dimethyl-4,7-diphenyl-1,10
-Phenanthroline, 5-phenyl-1,10-phena
Entroline, 5-nitro-1,10-phenanthroli
5-chloro-1,10-phenanthroline, 4,
4'-dimethyl-2,2'-bipyridine, 4,4'-di
Phenyl-2,2'-bipyridine, 2,2'-bipyridi
-3,3'-diol, 2,2'-bipyridine-4,
4'-dicarboxylic acid, 2,2'-biquinoline, 2,2 '
Bidentate consisting of -biquinoline-4,4'-dicarboxylic acid
Rank child. The monodentate ligand X is Cl⁻, Br⁻, I⁻No ha
Rogen ligand. Anion X is PF₆ ⁻, BF₄ ⁻, C
l⁻, Br⁻, I⁻, ClO₄ ⁻, SO₄ ^2-, NO₃
⁻. High-brightness fluorescent iridium selected from the complexes described above
Complexes and Their Rapid and Simple Synthesis by Microwave Heating