JPWO2014157207A1 - Luminescent metal complexes that respond to external stimuli - Google Patents

Abstract

A room temperature phosphorescent material responsive to an external stimulus is provided. The luminescent metal complex responsive to an external stimulus of the present invention has the general formula (I): wherein M is a trivalent metal atom and Ar is an optionally substituted arylene group or heteroarylene. And B is a ligand derived from a solvent.

Description

  The present invention relates to a luminescent metal complex that responds to external stimuli. More particularly, the present invention relates to room temperature phosphorescent materials that respond to external stimuli.

  A room temperature phosphorescent material is a material that utilizes light emission at room temperature from an excited triplet state, and has characteristics that are different from a fluorescent material that utilizes light emission from an excited singlet state, such as a long emission lifetime. Attention has been paid.

  For example, Patent Document 1 discloses room temperature phosphorescent materials that emit light in various wavelength ranges, and describes that these room temperature phosphorescent materials are useful as organic electroluminescence (organic EL) elements. . Non-Patent Document 1 discloses that a phosphorescent material is useful as an oxygen sensor.

  On the other hand, compounds that can reversibly change the color of light emitted by external stimuli are attracting attention as new materials that can give switching and sensing functions to luminescent materials, greatly expanding the range of applications for luminescent materials. Can do.

  For example, Non-Patent Document 2 discloses a light-emitting organic molecule into which a well-known photoresponsive site called diarylethene is introduced, and describes that fluorescence derived from an organic compound can be optically switched. Thus, in general, in order to impart a stimulus response function to a luminescent material, it is necessary to introduce an existing stimulus response site into the luminescent molecule.

  By the way, the metal complex is a group of compounds having a possibility of exhibiting room temperature phosphorescence if a ligand, a metal atom, and the like are well designed (Patent Document 1). The present inventors focused on 1,4,7-triazacyclononane-based ligands as ligands, and used triazacyclononane derivatives photofunctionalized with condensed polycyclic compounds such as naphthol and pyrenol. Then, trivalent gadolinium complexes were synthesized and their light emission characteristics were examined (Non-patent Documents 3 and 4). Specifically, a gadolinium complex having the following structure was synthesized and its light emission behavior was investigated.

  As a result of measuring the emission spectrum, the complex was found to be an unusual complex that exhibits phosphorescence at room temperature.

Japanese Patent Publication “JP 2007-210945 (published August 23, 2007)”

Xie, Z .; Ma, L .; deKrafft, K. E .; Jin, A .; Lin, W., J. Am. Chem. Soc., 132, p.922-923 (2010) Fukaminato, T .; Sasaki, T .; Kawai, T .; Tamai, N .; Irie, M., J. Am. Chem. Soc., 126, p.14843-14849 (2004) Nakamori, Kato, Nakai, Sobe, “Synthesis of New Lanthanide Complexes Using 1,4,7-Triazacyclononane Ligands with Naphtyl Groups and Their Luminescent Behavior”, 22nd Photochemistry Conference on Coordination Compounds Abstracts of Lectures, 47 pages (2010) Nakamori, Iwata, Nakai, Hayashi, Isobe, “Synthesis of New Lanthanide Complexes Using 1,4,7-Triazacyclononane Ligands with Pyrenyl Groups and Their Luminescent Behavior”, Lecture at the 60th Coordination Chemistry Conference Abstracts, page 327 (2010)

  However, the existing stimulation response sites are not introduced into the complexes as described in Non-Patent Document 3 and Non-Patent Document 4, and a normal stimulation response function cannot be expected. That is, it could not be predicted that the complex has a function of responding to external stimuli such as light. Therefore, no one thought that the complex could be applied as a light-emitting material having a reversible switching function and a sensing function.

  The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a room temperature phosphorescent material that responds to an external stimulus.

  As a result of intensive studies by the inventor on the above-mentioned problems, the metal complex having the structure represented by the general formula (I) is capable of emitting light and / or color by external stimulation without introducing an existing stimulation response site. Alternatively, the present inventors have found that the emission intensity can be reversibly changed and have completed the present invention.

  That is, the gist of the present invention is as follows.

  (1) The following general formula (I)

(Wherein, M is a trivalent metal atom, Ar is an optionally substituted arylene group or heteroarylene group, and B is a solvent-derived ligand). Luminescent metal complex.

  The metal complex that responds to an external stimulus according to the present invention emits light and / or luminescence by an external stimulus without introducing an existing stimulus responsive site by light emission based on fluorescence and phosphorescence of a ligand or metal atom. There is an effect that the intensity can be reversibly changed.

  Further, according to the metal complex of the present invention, the excitation wavelength, emission wavelength, and emission intensity can be easily controlled by selecting an Ar group or a metal atom.

  In addition, the reversible change in emission color and / or emission intensity due to the combination of light and oxygen molecules in the metal complex of the present invention can be suitably used as a reproducible optical sensor or oxygen sensor.

It is a figure which shows the external stimulus response phenomenon of this invention. 1 is an ORTEP diagram of gadolinium complex 1 in Example 1. FIG. 2 is a graph showing an absorption spectrum of gadolinium complex 1 in Example 1. FIG. It is a figure which shows the emission spectrum of the gadolinium complex 1 in Example 1 (THB without degassing, before light irradiation, emission color: blue, λex = 285 nm). It is a figure which shows the emission spectrum of the gadolinium complex 1 in Example 1 (after light irradiation (405 nm or less), emission color: red, (lambda) ex = 285 nm). It is a figure which shows the result of the repetition experiment in Example 1 (a vertical axis | shaft: relative light emission intensity which set the light emission intensity of the 1st time in 625 nm to 1.0, a horizontal axis: repetition frequency, (lambda) ex = 365nm, (lambda) irr = 365nm) . 6 is a graph showing an absorption spectrum of gadolinium complex 2 in Example 2. FIG. It is a figure which shows the emission spectrum of the gadolinium complex 2 in Example 2 (THB without degassing, before light irradiation, emission color: blue, λex = 285 nm). It is a figure which shows the emission spectrum of the gadolinium complex 2 in Example 2 (THF deaerated with nitrogen, emission color: green, λex = 285 nm). 6 is a graph showing an absorption spectrum of gadolinium complex 3 in Example 3. FIG. It is a figure which shows the emission spectrum of the gadolinium complex 3 in Example 3 (without deaeration THF, before light irradiation, luminescent color: nothing, (lambda) ex = 285nm). It is a figure which shows the emission spectrum of the gadolinium complex 3 in Example 3 (THF deaerated by nitrogen, emission color: blue, λex = 285 nm). Mixed solution of gadolinium complexes 1, 2 and 3 in Example 4 (complex 1 is 1.51 × 10 ⁻⁷ M, complex 2 is 5.79 × 10 ⁻⁷ M, complex 3 is 3.42 × 10 ⁻⁶ M It is a figure which shows the absorption spectrum of (including). Mixed solution of gadolinium complexes 1, 2 and 3 in Example 4 (complex 1 is 1.51 × 10 ⁻⁷ M, complex 2 is 5.79 × 10 ⁻⁷ M, complex 3 is 3.42 × 10 ⁻⁶ M (Including THF) (THF degassed with nitrogen, emission color: white, λex = 303 nm). Mixed solution of gadolinium complexes 1, 2 and 3 in Example 4 (complex 1 is 1.51 × 10 ⁻⁷ M, complex 2 is 5.79 × 10 ⁻⁷ M, complex 3 is 3.42 × 10 ⁻⁶ M (Including THF) (THF degassed with nitrogen, emission color: yellow, λex = 336 nm). Mixed solution of gadolinium complexes 1, 2 and 3 in Example 4 (complex 1 is 1.51 × 10 ⁻⁷ M, complex 2 is 5.79 × 10 ⁻⁷ M, complex 3 is 3.42 × 10 ⁻⁶ M (Including THF) emission spectrum (THF degassed with nitrogen, emission color: red, λex = 360 nm). 6 is an ORTEP diagram of terbium complex 4 in Example 5. FIG. 6 is a graph showing an absorption spectrum of terbium complex 4 in Example 5. FIG. It is a figure which shows the emission spectrum of the terbium complex 4 in Example 5 (solid line: THF without deaeration, emission color: green, (lambda) ex = 300nm) (dotted line: THF deaerated with nitrogen, emission color: green, (lambda) ex = 300nm. ). (A) is a schematic diagram explaining fluorescence, (b) is a schematic diagram explaining phosphorescence, and (c) is a schematic diagram explaining ff light emission.

  Hereinafter, although an example of an embodiment of the invention is explained in detail, the present invention is not limited to these. Unless otherwise specified in this specification, “A to B” indicating a numerical range means “A or more and B or less”.

  In this specification, “fluorescence” means light emission from an excited singlet state. In this specification, “phosphorescence” means light emission from an excited triplet state. Note that phosphorescence includes ff emission in addition to narrow phosphorescence.

FIG. 20A is a schematic diagram illustrating fluorescence, and FIG. 20B is a schematic diagram illustrating phosphorescence. As shown in FIG. 20 (a), if the material is excited by light or the like, the excited singlet state S _1. In this case, excessive energy is first released (see the dotted arrow in FIG. 20A). As the singlet state S ₁ returns to the ground state S ₀ , fluorescence is generated. In addition, as shown in FIG. 20B, phosphorescence is obtained when the excited singlet state S ₁ returns from the excited triplet state T ₁ to the ground state S ₀ after intersystem crossing from the excited singlet state S ₁ to the excited triplet state T ₁ . Occurs. In the present specification, as described above, ff emission is also included in phosphorescence. As shown in FIG. 20 (c), after being excited in the ligand and undergoing energy transfer from the excited singlet state S _{1 of} the ligand to the excited triplet state T ₁ and further to the lanthanide center, f-f emission occurs when returning from the excited state of the lanthanide center to the ground state S _0.

  Further, in the present specification, when the emission color is “red”, it is preferable to give an emission spectrum in a region of 620 to 750 nm. When the emission color is “green”, it is preferable to give an emission spectrum in the region of 495 to 570 nm. When the emission color is “blue”, it is preferable to give an emission spectrum in the region of 455 to 495 nm. When the emission color is “white” or “yellow”, the emission spectrum is a combination of the red, green, and blue light, so it is difficult to define the emission spectrum in a unified manner. For example, when the emission color is “white”, it is preferable to give an emission spectrum over the entire visible range of 400 to 760 nm. In addition, that the emission color is “no” means that the emission spectrum is hardly given in the entire visible range of 400 to 760 nm.

  The room temperature phosphorescent material (metal complex) having an external stimulus response function of the present invention is represented by the following general formula (I):

  (Wherein M is a trivalent metal atom, Ar is an optionally substituted arylene group or heteroarylene group, and B is a solvent-derived ligand).

Examples of the trivalent metal atom (M) include aluminum (Al ³⁺ ), gallium (Ga ³⁺ ), indium (In ³⁺ ), iridium (Ir ³⁺ ), bismuth (Bi ³⁺ ), cerium (Ce ³⁺ ), praseodymium. (Pr3 ⁺ ), neodymium (Nd3 ⁺ ), samarium (Sm3 ⁺ ), europium (Eu3 ⁺ ), gadolinium (Gd3 ⁺ ), terbium (Tb3 ⁺ ), dysprosium (Dy3 ⁺ ), holmium (Ho3 ⁺ E), el ³⁺ ), thulium (Tm ³⁺ ), ytterbium (Yb ³⁺ ). Among these, gadolinium is preferable from the viewpoint of excitation energy.

  The organic ligand of the metal complex has 1,4,7-triazacyclononane as a basic skeleton and is bonded to an Ar group from a nitrogen atom through a methylene group. The Ar group is bonded to an oxygen atom, and the oxygen atom is coordinated to the central metal together with the nitrogen atom of 1,4,7-triazacyclononane.

An arylene group removes two hydrogen atoms of two ring carbon atoms from a monocyclic or polycyclic aromatic hydrocarbon (in other words, one hydrogen atom from each of two ring carbon atoms. For example, a phenylene group (—C ₆ H ₄ —), a naphthylene group (—C ₁₀ H ₆ —), and the like. These arylene groups may be unsubstituted or the aromatic ring may be substituted with an alkyl group having 1 to 5 carbon atoms, an alkoxy group, a phenyl group, a halogen atom, or the like.

The condensed polycyclic arylene group refers to a group in which two or more aromatic rings are condensed among the above arylene groups. In the present invention, a condensed polycyclic arylene group in which 2 to 5 aromatic rings are condensed is preferably used, and examples thereof include a naphthylene group (—C ₁₀ H ₆ —), a disubstituted pyrene group and the like.

A heteroarylene group is a monocyclic or polycyclic heteroaromatic hydrocarbon that removes two hydrogen atoms of two ring carbon atoms (in other words, one each from two ring carbon atoms. A group formed by removing a hydrogen atom), and examples thereof include a 2,3-substituted pyridine group (—C ₅ H ₃ N—). These heteroarylene groups may be unsubstituted, or the aromatic ring may be substituted with an alkyl group having 1 to 5 carbon atoms, an alkoxy group, a phenyl group, a halogen atom, or the like.

The condensed polycyclic heteroarylene group refers to a group in which two or more aromatic rings are condensed among the above heteroarylene groups. In the present invention, a condensed polycyclic heteroarylene group in which 2 to 5 aromatic rings are condensed is preferably used, and examples thereof include 2,3-substituted quinoline (—C ₉ H ₅ N—).

In the general formula (I), the solvent-derived ligand B is a solvent molecule that has an unshared electron pair and coordinates without affecting the charge of the central metal atom. Specific examples include tetrahydrofuran (THF), methanol (MeOH), water (H ₂ O), and the like.

  Complexes preferably employed in the present invention include complexes represented by the following formulas 1a to 1f, but are merely examples and are not limited thereto.

  The complex of the general formula (I) can be appropriately synthesized based on the methods described in Non-Patent Documents 3 and 4 depending on the types of M, Ar, and B. Specifically, for example, 1, 4, 7 It can be obtained by reacting tris [2- (1-hydroxynaphthyl) methyl] -1,4,7-triazacyclononane with gadolinium trifluoromethanesulfonate.

  The inventors of the present invention can reversibly emit light and / or light intensity by an external stimulus even if a metal complex having a structure represented by the general formula (I) obtained by the above method does not introduce an existing stimulus response site. I found out that it can change.

  The external stimulus response phenomenon by the metal complex of the present invention is, for example, that room temperature phosphorescence is induced by stimulus 1, room temperature phosphorescence is quenched by stimulus 2, and only fluorescence emission is seen (FIG. 1). Further, depending on the metal complex, the emission intensity of phosphorescence may be changed by the stimulus 1 and the stimulus 2. Examples of the stimuli 1 and 2 include gas molecules such as light, heat, solvent, pressure, and oxygen. Among them, for example, when the metal atom is gadolinium, the stimulus 1 is preferably light, and the stimulus 2 is preferably an oxygen molecule. Further, when the metal atom is terbium, deaeration with nitrogen or argon is preferable as the stimulus 1, and oxygen molecules are preferable as the stimulus 2. In addition, the “B solution of the metal complex of the general formula (I)” illustrated in FIG. 1 is obtained by dissolving the metal complex of the general formula (I) in a solvent that provides the ligand B in the general formula (I). It is a solution.

  The emission of the complex in response to the external stimulus according to the present invention is based on the fluorescence and phosphorescence of the ligand or metal atom. By selecting an Ar group or a metal atom, the excitation wavelength, emission wavelength, or emission intensity can be easily controlled.

  The excitation wavelength (λex) can be appropriately determined according to the structure of the ligand and the like, but is preferably, for example, 250 to 760 nm, and more preferably 250 to 450 nm.

  Similarly, when light is used as the stimulus 1, the wavelength (λirr) of the light can be appropriately determined according to the structure of the ligand and the like, but is preferably 250 to 760 nm, for example, 250 to 450 nm. It is more preferable that

  In addition, the wavelength of the excitation wavelength and the light of the stimulus 1 can be a wavelength at which a peak is observed in the absorption spectrum of the metal complex. That is, if it is the same metal complex, the light of the same wavelength can be used as excitation light and stimulus 1 light.

  For example, when the metal complex of the present invention is represented by the above formula 1a, it can exhibit red phosphorescence. When the metal complex of the present invention is represented by the above formula 1b, it may exhibit green phosphorescence. When the metal complex of the present invention is represented by the above formula 1c, it can exhibit blue phosphorescence.

  When terbium is used as the metal atom, the stimulus 1 is preferably deaerated with nitrogen or argon, and the stimulus 2 is preferably oxygen. Moreover, phosphorescence by a terbium complex is ff light emission from the terbium ion which exists in the center. From the terbium complex, almost no fluorescence derived from the ligand is observed. For example, when the metal complex of the present invention is represented by the above formula 1d, it can exhibit green phosphorescence. In the case of a terbium complex, the emission intensity can be changed by stimuli 1 and 2.

  The composition according to the present invention contains the metal complex according to the present invention. The composition of the present invention may contain a substance other than the metal complex according to the present invention, if necessary. Such a substance is not particularly limited as long as it does not inhibit the external stimulus response phenomenon caused by the metal complex.

  The composition according to the present invention is a metal complex according to the present invention, and may include two or more metal complexes having different Ar, and may include three or more. In addition, the composition according to the present invention may include two or more metal complexes according to the present invention that exhibit phosphorescence that gives an emission spectrum in a wavelength range different from each other. The above may be included.

  The composition according to the present invention may contain at least two of the complexes represented by the above formulas 1a to 1f. For example, the composition containing the metal complex represented by the formula 1a, the metal complex represented by the formula 1b, and the metal complex represented by the formula 1c has an excitation wavelength of 303 nm. White phosphorescence is shown. When the excitation wavelength is 336 nm, yellow phosphorescence is shown. When the excitation wavelength is 360 nm, red phosphorescence is shown. In addition, as mentioned above, the phosphorescence which each of the metal complex represented by said Formula 1a, 1b, and 1c respond | corresponds to the three primary colors of light. However, the white phosphorescence emitted from the composition is not simply obtained by superimposing the phosphorescence obtained separately from each of the metal complexes, but is obtained from a composition in which the metal complexes are mixed.

  When using two or more metal complexes having Ar different from each other or phosphorescence that gives phosphorescence spectra in different wavelength ranges, the ratio of mixing these metal complexes depends on the required emission color, etc. What is necessary is just to determine suitably according to. For example, the composition according to the present invention includes 0 to 100 mol% of the metal complex represented by the formula 1a, 0 to 100 mol% of the metal complex represented by the formula 1b, and the metal represented by the formula 1c. Complex 0-100 mol% may be included.

  In addition, the reversible change in emission color and / or emission intensity caused by an external stimulus such as a combination of light and oxygen molecules in the present invention can be suitably used as a reproducible optical sensor or oxygen sensor. In addition, the metal complex and the composition according to the present invention exhibit a reversible change in emission color and / or emission intensity as described above, and therefore are suitably used for an optical switch and an optical switching system including the optical switch. can do.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention can also be configured as follows.

  (1) The following general formula (I)

(Wherein, M is a trivalent metal atom, Ar is an optionally substituted arylene group or heteroarylene group, and B is a solvent-derived ligand). Luminescent metal complex.

  (2) The luminescent metal complex which responds to the external stimulus as described in (1) whose trivalent metal atom is gadolinium.

  (3) The luminescent metal complex which responds to the external stimulus as described in (1) or (2), wherein Ar is a condensed polycyclic arylene group or a condensed polycyclic heteroarylene group in which 2 to 5 aromatic rings are condensed.

  (4) The luminescent metal complex which responds to the external stimulus as described in (3) whose Ar is a disubstituted pyrene group.

  (5) The luminescent metal complex according to any one of (1) to (4), wherein the external stimulus is light and oxygen molecules, and phosphorescence at room temperature is expressed by the light stimulus.

  (6) A reproducible optical sensor comprising a luminescent metal complex that responds to an external stimulus according to any one of (1) to (5).

  (7) A reproducible oxygen sensor comprising a luminescent metal complex that responds to an external stimulus according to any one of (1) to (5).

  (8) An optical switch comprising a luminescent metal complex that responds to an external stimulus according to any one of (1) to (5).

  (9) An optical switching system including the optical switch according to (8).

  The present invention can also be configured as follows.

  <1> A luminescent metal complex that responds to an external stimulus represented by the general formula (I).

  <2> The luminescent metal complex which responds to the external stimulus according to <1>, wherein the trivalent metal atom is gadolinium.

  <3> The luminescent metal complex which responds to the external stimulus according to <1>, wherein the trivalent metal atom is terbium.

  <4> Luminescence in response to an external stimulus according to any one of <1> to <3>, wherein Ar is a condensed polycyclic arylene group or a condensed polycyclic heteroarylene group in which 2 to 5 aromatic rings are condensed. Metal complex.

  <5> The luminescent metal complex responding to an external stimulus according to <4>, wherein Ar is a disubstituted pyrene group.

  <6> The luminescent metal complex according to <1> to <5>, wherein the external stimulus is light and oxygen molecules, and phosphorescence at room temperature is exhibited by the light stimulus.

  <7> A composition containing a luminescent metal complex that responds to an external stimulus according to any one of <1> to <6>, wherein the composition comprises a luminescent metal complex having different Ar. A composition comprising two or more.

  <8> A reproducible optical sensor comprising the luminescent metal complex that responds to an external stimulus according to any one of <1> to <6>, or the composition according to <7>.

  <9> A reproducible oxygen sensor comprising the luminescent metal complex that responds to an external stimulus according to any one of <1> to <6>, or the composition according to <7>.

  <10> A light-emitting metal complex that responds to an external stimulus according to any one of <1> to <6>, or a composition according to <7>.

  <11> An optical switching system including the optical switch according to <10>.

  Hereinafter, the present invention will be described in more detail with reference to examples.

  In the present specification, “before light irradiation” means that light irradiation as the stimulus 1 is not performed.

[Example 1]
A trivalent gadolinium complex 1 having the structure shown below was synthesized according to the methods described in Non-Patent Documents 3 and 4. The gadolinium complex 1 corresponds to the metal complex represented by the above formula 1a.

  Specifically, first, 1,4,7-triazacyclononane (100 mg, 0.77 mmol) and paraformaldehyde (72 mg, 2.4 mmol) were dissolved in toluene and stirred at 80 ° C. for 40 minutes. Then, 1-pyrenol (600 mg, 2.8 mmol) was added and stirred at 80 ° C. for 4 hours. The resulting yellow powder was filtered off and washed with methanol to obtain 1,4,7-tris [2- (1-hydroxypyrenyl) methyl] -1,4,7-triazacyclononane). Obtained (yield: 516 mg, yield: 81%).

The obtained 1,4,7-tris [2- (1-hydroxypyrenyl) methyl] -1,4,7-triazacyclononane (82 mg, 0.10 mmol) and gadolinium trifluoromethanesulfonate (Gd (OTf ₃ , 60 mg, 0.10 mmol) was stirred in a mixed solvent of acetone / THF (100/1) at 30 ° C. for 5 minutes. To this solution was added triethylamine (0.3M, 1 mL, 0.30 mmol), and the mixture was stirred at 30 ° C. for 3 hours. The resulting yellow powder was filtered off and washed with acetone to obtain gadolinium complex 1 (yield: 80 mg, yield: 76%). By recrystallizing the gadolinium complex 1 using a mixed solvent of ethyl acetate / THF, crystals suitable for X-ray structural analysis were obtained.

The results of elemental analysis are shown below.
Anal. _{Calcd for C 61 H 50 GdN 3} O 4: C, 70.02; H, 4.82; N, 4.02%. Found: C, 69.76; H, 4.66; N, 4.12%.

  The crystal of the obtained gadolinium complex 1 was subjected to structural analysis by X-ray diffraction. FIG. 2 shows an ORTEP diagram obtained by structural analysis. As a result, the obtained gadolinium complex 1 has a seven-coordinate structure in which the oxygen atom of THF is coordinated to one side of a distorted octahedron formed by three nitrogen atoms and three oxygen atoms of the ligand. It became clear that it was a complex molecule.

  Next, the absorption spectrum of this gadolinium complex 1 was measured in THF. The measurement results are shown in FIG. As is apparent from FIG. 3, absorption derived from the pyrene ring was observed at around 400 nm.

  A sample of gadolinium complex 1 was prepared in a capped quartz four-sided cell using THF that was not degassed. When photoexcitation was performed in the absorption band (410 nm or less) of the gadolinium complex 1, a blue emission spectrum derived from the fluorescence of the ligand as shown in FIG. 4 was obtained. Actually, the gadolinium complex 1 was excited by 285 nm light (λex).

  When the cell was continuously irradiated with 285 nm light (λirr) at room temperature, the emission color changed to red, and the emission spectrum changed as shown in FIG. That is, room temperature phosphorescence of gadolinium complex 1 was induced by light irradiation of 410 nm or less.

  In addition, the said emission spectrum obtained by light irradiation corresponded with the emission spectrum of the gadolinium complex 1 in the deaeration THF measured separately. This means that as the stimulus 1 in the gadolinium complex 1, both light irradiation and deaeration with nitrogen or argon can be used.

  When the cell cap was opened and the gadolinium complex 1 sample was exposed to air, the emission color changed to the original blue color. This is the quenching of light emission by oxygen, usually seen in room temperature phosphorescent complexes. When the cap is tightened and the light of 410 nm or less is continuously irradiated again, the emission color changes to red.

  FIG. 6 shows the result of repeated emission color switching. Light having a wavelength of 365 nm was used for light stimulation (λirr), and the emission intensity at 625 nm in phosphorescence was monitored (λex = 365 nm). In addition, the vertical axis | shaft of FIG. 6 is a relative light emission intensity which set the light emission intensity of the 1st time in 625 nm to 1.0, and a horizontal axis is the frequency | count of repetition of light stimulation.

[Example 2]
The following gadolinium complex 2 was obtained by the same method as in Example 1 except that 1-naphthol was used instead of 1-pyrenol. The gadolinium complex 2 corresponds to the metal complex represented by the above formula 1b.

  The absorption spectrum of this gadolinium complex 2 was measured in THF. The measurement results are shown in FIG. As is clear from FIG. 7, absorption derived from the naphthalene ring was observed at around 335 nm.

  A sample of gadolinium complex 2 was prepared in a capped quartz four-sided cell using undegassed THF. When photoexcitation was performed in the absorption band (not more than 350 nm) of the gadolinium complex 2, a blue emission spectrum derived from the fluorescence of the ligand as shown in FIG. 8 was obtained. Actually, the gadolinium complex 2 was excited by 285 nm light (λex).

  When the cell was continuously irradiated with 285 nm light (λirr) at room temperature, the emission color changed to green. Moreover, in the cell from which the blue emission spectrum derived from the fluorescence was obtained, when the THF was degassed using nitrogen instead of light irradiation, the emission color similarly changed to green. FIG. 9 shows an emission spectrum obtained by degassing THF. Note that the emission spectrum shown in FIG. 9 coincided with the emission spectrum obtained by light irradiation. That is, room temperature phosphorescence of gadolinium complex 2 was induced by both light irradiation and deaeration.

Example 3
The following gadolinium complex 3 was obtained by the same method as in Example 1 except that 2,4-dimethylphenol was used instead of 1-pyrenol. The gadolinium complex 3 corresponds to the metal complex represented by the above formula 1c.

  The absorption spectrum of this gadolinium complex 3 was measured in THF. The measurement results are shown in FIG. As is clear from FIG. 10, the absorption derived from the benzene ring was observed around 300 nm.

  A sample of gadolinium complex 3 was prepared in a capped quartz four-sided cell using THF that was not degassed. When photoexcitation was performed in the absorption band (310 nm or less) of the gadolinium complex 3, an emission spectrum (luminescence color: none) derived from the fluorescence of the ligand as shown in FIG. 11 was obtained. Actually, the gadolinium complex 3 was excited by 285 nm light (λex).

  When the cell was continuously irradiated with 285 nm light (λirr) at room temperature, the emission color changed to blue. Moreover, in the cell from which the emission spectrum derived from the fluorescence (emission color: none) was obtained, when THF was degassed using nitrogen instead of light irradiation, the emission color similarly changed to blue. FIG. 12 shows an emission spectrum obtained by degassing THF. In addition, the emission spectrum shown in FIG. 12 was in agreement with the emission spectrum obtained by light irradiation. That is, room temperature phosphorescence of gadolinium complex 3 was induced by both light irradiation and deaeration.

Example 4
A mixed solution of gadolinium complexes 1, 2 and 3 obtained in Examples 1 to 3 was prepared. As described above, the gadolinium complexes 1, 2 and 3 have different Ar in the general formula (I), and also have different phosphorescent emission colors. The mixed solution is prepared by dissolving gadolinium complex 1 in a solvent at 1.51 × 10 ⁻⁷ M, gadolinium complex 2 at 5.79 × 10 ⁻⁷ M, and gadolinium complex 3 at 3.42 × 10 ⁻⁶ M in a solvent. did. THF was used as the solvent.

  The measurement result of the absorption spectrum of the mixed solution is shown in FIG. As is clear from FIG. 13, absorptions derived from gadolinium complexes 1, 2 and 3 were observed at 410 nm or less.

  A sample of the mixed solution was prepared in a capped quartz four-sided cell using undegassed THF. When photoexcitation was performed in the absorption band (410 nm or less) of the mixed solution, a blue emission spectrum derived from fluorescence from the ligand of the complex contained in the mixed solution was obtained (not shown).

  When the cell was continuously irradiated with 285 nm light (λirr) at room temperature, the emission color changed to white (λex = 303 nm), yellow (λex = 336 nm), or red (λex = 360 nm). did. In addition, in the cell where the emission spectrum derived from the fluorescence was obtained, when THF was degassed using nitrogen instead of light irradiation, the emission color similarly changed to white, yellow, or red depending on the excitation wavelength. changed. FIG. 14 (white, λex = 303 nm), FIG. 15 (yellow, λex = 336 nm), and FIG. 16 (red, λex = 360 nm) show the emission spectra obtained by degassing THF. The emission spectra shown in FIGS. 14, 15 and 16 coincided with the emission spectrum obtained by light irradiation. That is, room temperature phosphorescence of the complex contained in the mixed solution was induced by both light irradiation and degassing. Furthermore, in the mixed solution, the emission color was different from the case where each gadolinium complex was used alone. In addition, the emission color was changed by changing the excitation wavelength.

Example 5
The following terbium complex 4 was obtained by the same method as in Example 3 except that terbium trifluoromethanesulfonate (Tb (OTf) ₃ ) was used instead of Gd (OTf) ₃ . The terbium complex 4 corresponds to the metal complex represented by the above formula 1d.

The results of elemental analysis are shown below.
Anal. _{Calcd for C 37 H 50 N 3} O 4 Tb: C, 58.49; H, 6.63; N, 5.53%. Found: C, 58.40; H, 6.60; N, 5.50%.

  The crystal of the obtained terbium complex 4 was subjected to structural analysis by X-ray diffraction. FIG. 17 shows an ORTEP diagram obtained by structural analysis.

  The absorption spectrum of this terbium complex 4 was measured in THF. The measurement results are shown in FIG. As is clear from FIG. 18, the absorption derived from the benzene ring was observed near 300 nm.

  A sample of terbium complex 4 was prepared in a capped quartz four-sided cell using THF that was not degassed. When photoexcitation was performed in the absorption band (310 nm or less) of the terbium complex 4, a green emission spectrum as shown by the solid line in FIG. 19 was obtained. Actually, the terbium complex 4 was excited with light of 300 nm (λex).

  When the cell was stimulated with nitrogen as a stimulus 1, the emission intensity increased about 15 times (λex = 300 nm) as shown by the dotted line in FIG. That is, room temperature phosphorescence of the terbium complex 4 was induced by deaeration.

  When oxygen was added to the cell as stimulus 2 at room temperature, the emission spectrum changed as shown by the solid line in FIG.

  The present invention can be suitably used, for example, as a reproducible optical sensor or oxygen sensor.

Claims (11)

The following general formula (I)

Wherein M is a trivalent metal atom, Ar is an optionally substituted arylene group or heteroarylene group, and B is a solvent-derived ligand. Luminescent metal complex that responds to external stimuli.   The luminescent metal complex in response to an external stimulus according to claim 1, wherein the trivalent metal atom is gadolinium.   The luminescent metal complex in response to an external stimulus according to claim 1, wherein the trivalent metal atom is terbium.   The Ar is a condensed polycyclic arylene group or a condensed polycyclic heteroarylene group in which 2 to 5 aromatic rings are condensed, and responds to an external stimulus according to any one of claims 1 to 3. Luminescent metal complex.   The luminescent metal complex in response to an external stimulus according to claim 4, wherein Ar is a disubstituted pyrene group.   6. The luminescent metal complex in response to an external stimulus according to any one of claims 1 to 5, wherein the external stimulus is light and oxygen molecules, and room temperature phosphorescence is expressed by the light stimulus. A composition comprising a luminescent metal complex responsive to an external stimulus according to any one of claims 1-6,
The said composition contains two or more luminescent metal complexes which have mutually different Ar, The composition characterized by the above-mentioned.   A reproducible optical sensor comprising the luminescent metal complex responsive to an external stimulus according to any one of claims 1 to 6, or the composition according to claim 7.   A reproducible oxygen sensor comprising the luminescent metal complex that responds to an external stimulus according to any one of claims 1 to 6, or the composition according to claim 7.   An optical switch comprising the luminescent metal complex responsive to an external stimulus according to any one of claims 1 to 6, or the composition according to claim 7.   An optical switching system including the optical switch according to claim 10.

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