JP5747247B2 - Organic / fluorescent metal hybrid polymer and its ligand - Google Patents

Description

  TECHNICAL FIELD The present invention relates to an organic / metal hybrid polymer having fluorescence, and in particular, an organic / metal hybrid polymer and a ligand thereof that can reversibly lose fluorescence, that is, can repeat disappearance of fluorescence and its recovery. About.

  An organic / metal hybrid polymer is a polymer in which organic sites (organic modules) and metal species are hybridized (composited) on a nanoscale, and is expected to exhibit electronic, optical, magnetic, and catalytic functions not found in conventional organic polymers. ing. The inventors of the present invention have found that certain organic / metal hybrid polymers have excellent electrochromic properties of developing / decoloring with a specific color by oxidation / reduction of the metal ions by application of voltage. Based on various organic / metal hybrid polymers having such characteristics, bisterpyridine derivatives used as ligands thereof, and various applications to display devices, etc., patent applications have been made (Patent Documents 1 to 3). 10).

  However, it has not been known so far to achieve the visual and optical effects by the organic / metal hybrid polymer by a method other than the application of voltage as described above.

  An object of the present invention is to provide an organic / metal hybrid polymer that has fluorescence and can be reversibly lost and revived by exposure to a specific atmosphere.

According to one aspect of the present invention, there is provided an organic / fluorescent metal hybrid polymer having a structure represented by the following general formula, including a ligand of a bisterpyridine derivative, a rare earth metal ion, and a counter cation. .

Where L is a rare earth metal ion, X is a spacer having at least one aromatic ring between two terpyridyl substituents, at least one of substituents A1 and A2, and at least one of substituents A3 and A4 is a carboxyl group is there.
Here, the substituents A1 to A4 may be a carboxyl group or a substituent represented by the following structural formula.

The spacer may have the following structure.

However, R is a substituent represented by the following structural formula having a PEG group in the side chain.

The spacer may have any of the following structures.



However, R _{1 to} R ₆ are each independently selected from the group consisting of a plurality of structures represented by R, and R ₇ and R ₈ are selected from the plurality of structures shown as options for R ₇ and R _8. The plurality of R ″ are selected independently from each other from the group consisting of a plurality of structures shown as options for the R ″, and 1 ≦ X ≦ 100,000. n ≦ 20.
The counter cation may be selected from the group consisting of Na, K, HN (R) ₃ and N (R) ₄ . Where R is -CH ₃
- (CH _{2) n} CH _{3
-CH 2 CH 2 O (CH 2} CH 2) n CH 3
(However, 1 ≦ n ≦ 5)
Selected from the group consisting of
The rare earth metal may be Eu or Tb.
The organic / fluorescent metal hybrid polymer may also lose fluorescence upon exposure to acid vapor.
Also, lost fluorescence may be restored by exposure to amines or ammonia vapors.
According to another aspect of the present invention, there is provided a ligand composed of a bisterpyridine derivative having a structure represented by the following general formula.

However, X is a spacer having at least one aromatic ring between two terpyridyl substituents, at least one of substituents A1 and A2, and at least one of substituents A3 and A4 is a carboxyl group.
Here, the substituents A1 to A4 may be a carboxyl group or a substituent represented by the following structural formula.

The spacer may have the following structure.

(Where R is a substituent represented by the following structural formula having a PEG group in the side chain)

The spacer may have any of the following structures.


However, R _{1 to} R ₆ are each independently selected from the group consisting of a plurality of structures represented by R, and R ₇ and R ₈ are selected from the plurality of structures shown as options for R ₇ and R _8. The plurality of R ″ are selected independently from each other from the group consisting of a plurality of structures shown as options for the R ″, and 1 ≦ X ≦ 100,000. n ≦ 20.

  According to the present invention, an organic / metal hybrid polymer having fluorescence can be provided. In addition, this organic / metal hybrid polymer has a unique property that is not found in fluorescent materials so far, in which the fluorescence disappearance-resurrection cycle in which the fluorescence disappears and is restored can be repeated. In addition, since the organic / metal hybrid polymer of the present invention can form a self-supporting film, the degree of freedom of processing in various applications is great.

The figure which shows the process of the ligand synthesis | combination in the Example of this invention. Eu (NO ₂₎ shows an ultraviolet-visible absorption spectrum changed in methanol when added stepwise by 0.1mol equivalents synthesized ligand in Example ₃ of the invention. The figure which shows reaction which synthesize | combines the organic / metal hybrid polymer in the Example of this invention from the ligand obtained as shown in FIG. 1 is an AFM image of an organic / europium hybrid polymer according to an embodiment of the present invention. The figure which shows the fluorescence of the organic / europium hybrid polymer by one Example of this invention. FIG. 4 is a diagram showing reversible disappearance and restoration of fluorescence of an organic / europium hybrid polymer according to an embodiment of the present invention.

  The organic / metal hybrid polymer of the present invention has a structure represented by the following general formula, which includes a bisterpyridine derivative ligand, a rare earth metal ion, and a counter cation.

Here, L is a rare earth metal ion generally used as a phosphor activator such as europium and terbium, X is a spacer having at least one aromatic ring between two terpyridyl substituents, A1 to A4 are -COOH,

But at least one of A1 and A2 and at least one of A3 and A4 is a carboxyl group. For example, the spacer X having the following structure may be used.

(Where R is a substituent represented by the following structural formula having a PEG group in the side chain)

The spacer X can take various structures other than that. Non-limiting examples of spacers are shown below.

In the spacer structures listed above, R _{1 to} R ₆ can independently take any structure represented by R. R ₇ and R ₈ as well as a plurality of R ″ can be arbitrarily selected from a plurality of structures shown as options. In addition, 1 ≦ X ≦ 100,000, and 1 ≦ n ≦ 20 It is.

Examples of counter cations include Na, K, HN (R) ₃ , N (R) ₄
Etc. can be used. Here, R represents the following structure.
-CH ₃
- (CH _{2) n} CH _{3
-CH 2 CH 2 O (CH 2} CH 2) n CH 3
(However, 1 ≦ n ≦ 5)

  The above-described organic / metal hybrid polymer of the present invention is synthesized by refluxing the ligand having the structure described above and the rare earth metal salt in methanol.

  In addition, in addition to methanol, an inorganic base such as KOH or NaOH, an organic base such as triethylamine, or the like can be used for refluxing. In addition to rare earth metal nitrates such as Eu and Tb, for example, lanthanoid triflates can be used as rare earth metal salts.

  The organic / metal hybrid polymer synthesized in this way can form a self-supporting film on its own even without mixing a substance that helps to form a film such as another polymer or to improve its strength. In the case of an application in which a support cannot be used, there is an advantage that a film that emits strong fluorescence despite being thin can be provided.

  Furthermore, when this membrane is exposed to a vapor atmosphere of various acids such as hydrochloric acid (generally, any acid that generates protons), the fluorescence is almost quenched, and the fluorescence is increased due to such treatment. By exposing the film with the loss of vapor to the atmosphere of various amines such as triethylamine or ammonia vapor, the fluorescence is almost restored to the original state. This fluorescence loss-resurrection cycle can be repeated 10 times or more. That is, it was confirmed that the loss of fluorescence in the organic / metal hybrid polymer of the present invention was reversible.

  In the following, examples of the synthesis and emission characteristics of organic / metal hybrid polymers using europium and terbium as fluorescent metals will be described.

  First, a bis (terpyridine) ligand having a PEG chain in the side chain was synthesized. A series of steps of this synthesis is shown in FIG. From the titration test using the thus obtained ligand and europium nitrate, as shown in FIG. 2, it was confirmed that the complex was formed with ligand: metal = 1: 1. FIG. 2 shows the change in the absorbance spectrum in the ultraviolet region during the process of adding europium metal salt to the ligand-only solution. The change in the peak of the spectrum is seen up to the ligand: metal = 1: 1, but it does not change even after the addition of a metal salt, so that the complex is formed with the ligand: metal = 1: 1. Is stable.

Next, the ligand synthesized in this way is mixed with Eu (NO ₂ ) ₃ (or Tb (NO ₂ ) ₃ ), Et ₃ N and MeOH as shown in FIG. 3 and refluxed. An organic / europium hybrid polymer (or organic / terbium hybrid polymer) was synthesized quantitatively (ie, almost 100%). Note that lanthanoid triflate Ln (OTf) ₃ or the like can be used in place of the nitrate as a rare earth element supply source.

  Hereinafter, the fluorescence characteristics of the organic / europium hybrid polymer will be described, but the organic / terbium hybrid polymer also showed the same tendency with respect to other characteristics although the fluorescent color was different.

In addition, regarding a metal salt here, other than Eu salt and Tb salt, if it is rare earth salt, substitution is possible. As the base, in addition to Et ₃ N, an inorganic base such as NaOH and KOH, and an organic base such as Bu ₃ N can be substituted. Further, the solvent can be replaced if it is an alcohol type such as ethanol or ethylene glycol.

  The specific synthesis process of the ligand and the organic / metal hybrid polymer was as follows.

○ Synthesis of Diethnyl-4 '-(4-bromophenyl) -2,2': 6 ', 2''-terpyridine-6,6''-dicarboxylate
4 '-(4-bromophenyl) -2,2': 6 ', 2''-terpyridine-6,6''-dicarbonitrile (8.77 g, 20.0 mmol) in concentrated sulfuric acid (90 mL), acetic acid (90 mL) Then, a mixed solvent of water (20 mL) was stirred at 100 ° C. for 12 hours, and then added to 800 mL of ice water. The precipitate was collected, washed with water and acetonitrile and dried. 24 g of thiotyl chloride was added to 600 mL of ethanol in an ice bath, and the mixture was stirred at room temperature for 15 minutes, the above precipitate was added, and the mixture was stirred at reflux for 12 hours. After the solvent was distilled off, 1000 mL of chloroform was added, and the mixture was washed with 5% NaHCO ₃ aqueous solution. The organic layer was separated, dried over MgSO _4, filtered, evaporated, and purified by silica gel column chromatography (eluent: CH ₂ Cl ₂ : MeOH = 99: 1), dimethnyl-4'- (4-bromophenyl) -2,2 ′: 6 ′, 2 ″ -terpyridine-6,6 ″ -dicarboxylate was obtained. (5.01g, 47.1%)

¹ H NMR (300 MHz, CDCl ₃ , 298 K) δ = 8.81 (d, 2H, J = 7.8 Hz), 8.80 (s, 2H), 8.16 (d, 2H, J = 7.8 Hz), 8.01 (t, 2H, J = 7.8 Hz), 7.76 (d, 2H, J = 8.8 Hz), 7.66 (d, 2H, J = 8.8 Hz), 4.52 (q, 4H, J = 7.1 Hz), 1.49 (t, 6H, J = 7.1 Hz); ¹³ C NMR (75 MHz, CDCl ₃ , 298 K) δ = 165.2, 156.2, 155.2, 149.5, 147.9, 137.8, 137.3, 132.1, 129.0, 125.1, 124.4, 123.6, 119.6, 61.9, 14.3.

○ Diethnyl-4 '-(4- (4,4,5,5-tetramethyl-1,3,2-dioxaboryl) phenyl) -2,2': 6 ', 2``-terpyridine-6,6'' -dicarboxylate synthesis
Dimethnyl-4 '-(4-bromophenyl) -2,2': 6 ', 2''-terpyridine-6,6''-dicarboxylate (5.32 g, 10.0 mmol) in DMSO (40 mL) and bispinacolato Diboron (bispinacolatodiboron) (2.79 g, 11.0 mmol), potassium acetate (4.91 g, 50.0 mmol) and PdCl ₂ (PPh ₃ ) ₂ (702 mg, 1.0 mmol) were added, and the mixture was heated at 120 ° C. under a nitrogen atmosphere. Stir for hours. After cooling to room temperature, the catalyst was removed by filtration and washed with chloroform. The mother liquor was washed with water, the organic layer was separated, dried over magnesium sulfate, filtered, evaporated, and purified by silica gel column chromatography (eluent: CH ₂ Cl ₂ ), diethnyl-4'- (4- (4,4,5,5-tetramethyl-1,3,2-dioxaboryl) phenyl) -2,2 ′: 6 ′, 2 ″ -terpyridine-6,6 ″ -dicarboxylate was obtained. (5.21 g, 89.9%)

¹ H NMR (300 MHz, CDCl ₃ , 298 K) δ = 8.87 (s, 2H), 8.83 (d, 2H, J = 7.8 Hz), 8.17 (d, 2H, J = 7.8 Hz), 8.01 (t, 2H, J = 7.8 Hz), 7.98 (d, 2H, J = 8.2 Hz), 7.92 (d, 2H, J = 8.2 Hz), 4.52 (q, 4H, J = 7.1 Hz), 1.49 (t, 6H, J = 7.1 Hz), 1.39 (s, 12H); ¹³ C NMR (75 MHz, CDCl ₃ , 298 K) δ = 165.4, 156.3, 155.2, 150.5, 147.9, 140.9, 137.8, 135.4, 126.7, 125.0, 124.4, 120.0, 84.0, 61.9, 24.9, 14.3.

○ Ligand synthesis
Diethnyl-4 '-(4- (4,4,5,5-tetramethyl-1,3,2-dioxaboryl) phenyl) -2,2': 6 ', 2``-terpyridine-6,6''- 1,4-dibromo-2,5-bis (3,4,5-tris (2- (2- (2-methoxyethoxy) ethoxy) ethoxy) benzyloxy) in DMSO (2 mL) solution of dicarboxylate (127 mg, 0.22 mmol) ) benzene (142 mg, 0.10 mmol), potassium carbonate (69.1 mg, 0.50 mmol) and PdCl ₂ (PPh ₃ ) ₂ (7.02 mg, 10 μmol) were added, and the mixture was stirred at 120 ° C. for 24 hours under a nitrogen atmosphere. After cooling to room temperature, the catalyst was removed by filtration and washed with chloroform. The mother liquor was washed with water, the organic layer was separated, dried over magnesium sulfate, filtered, evaporated, and purified by silica gel column chromatography (eluent: CH ₂ Cl ₂ ) and recycled GPC to give a viscous solid Got. (38.1 mg, 8.8%)

¹ H NMR (300 MHz, CDCl ₃ , 298 K) δ = 8.93 (s, 4H), 8.87 (d, 4H, J = 7.9 Hz), 8.19 (d, 4H, J = 7.9 Hz), 8.04 (t, 4H, J = 7.9 Hz), 8.03 (d, 2H, J = 8.2 Hz), 7.84 (d, 2H, J = 8.2 Hz), 7.21 (s, 2H), 6.57 (s, 4H), 5.02 (s, 4H), 4.54 (q, 8H, J = 7.1 Hz), 4.07 (m, 12H), 3.79-3.40 (m, 60H) 3.34 (s, 6H), 3.29 (s, 12H), 1.50 (t, 12H, J = 7.1 Hz); ¹³ C NMR (75 MHz, CDCl ₃ , 298 K) δ = 165.3, 156.3, 155.3, 152.6, 150.4, 150.2, 148.0, 139.2, 137.8, 137.0, 132.5, 131.2, 130.3, 127.1, 125.1, 124.4, 119.7, 117.2, 106.1, 72.3, 71.9, 71.8, 70.6, 70.5, 70.4, 69.6, 68.7, 61.9, 58.9, 14.4.

Furthermore, the viscous solid (170 mg, 79 μmol) was dissolved in 5 mL of THF-H ₂ O (v / v = 1: 1) mixed solvent, and sodium hydroxide (12.6 mg, 314 μmol) was added and refluxed for 12 hours. Stir. After cooling to room temperature, the solution was neutralized with 1 M aqueous HCl, and THF was removed under reduced pressure. The aqueous layer was extracted with chloroform, the organic layer was separated, dried over MgSO ₄ , filtered, evaporated, and purified by recycle GPC to give the ligand (117 mg, 71.8%).

¹ H NMR (300 MHz, CDCl ₃ , 298 K) δ = 8.95 (d, 4H, J = 7.9 Hz), 8.82 (s, 4H),, 8.34 (d, 4H, J = 7.9 Hz), 8.17 (t, 4H, J = 7.9 Hz), 7.99 (d, 2H, J = 8.2 Hz), 7.86 (d, 2H, J = 8.2 Hz), 7.20 (s, 2H), 6.60 (s, 4H), 5.04 (s, 4H), 4.11 (m, 12H), 3.83-3.40 ( m, 60H) 3.34 (s, 6H), 3.21 (s, 12H)

Polymer synthesis An equimolar amount of ligand and Eu (NO ₂ ) ₃ were stirred under reflux in anhydrous methanol bubbling with argon gas for 24 hours. After the solvent was distilled off, the residue was dissolved in methanol, precipitated in a mixed solvent of chloroform-hexane, recovered by filtration, and washed with water and chloroform to obtain a yellow solid quantitatively.

  FIG. 4 shows an AFM image of an organic / europium hybrid polymer (hereinafter simply referred to as an organic / metal hybrid polymer) having bis (terpyridine) as a ligand prepared as described above.

  The obtained organic / metal hybrid polymer itself was capable of forming a self-supporting film. Specifically, such a film was prepared as follows.

○ Creation of self-supporting membrane Dissolve the synthesized organic / metal hybrid polymer (10 mg) in methanol (0.5 mL), cast into a Teflon petri dish, and slowly remove the solvent to obtain a self-supporting membrane. Dried.

  Furthermore, a thinner film could be produced as follows.

Preparation of Thin Film A methanol solution (1 mL) of the synthesized organic / metal hybrid polymer (41 μg) was obtained by spin casting on a glass substrate, and dried under reduced pressure.
Further, as described below, it was confirmed that the film was fluorescent by irradiating the film with ultraviolet rays.

  The upper left photograph in FIG. 5 is a photograph of a state in which visible light is irradiated from the upper left with the experimentally prepared organic / metal hybrid polymer film held with tweezers. In this state, the film does not fluoresce, so the portion of the film where the reflected light is incident on the imaging substrate appears bright, but the other part appears dark because the dark background can be seen through the film. ing. As a result, the film in this photo appears to have a very strong contrast. In this state, a photograph of a state in which irradiation with ultraviolet rays having a wavelength of 345 nm is further added is shown in the upper right of FIG. Since fluorescence is emitted from the entire film, the entire film appears to have almost uniform brightness in the photograph in the upper right of FIG. Since FIG. 5 is a monochrome photograph, the entire film appears bright, but actually the entire film emitted red fluorescence. Further, the lower right photograph in FIG. 5 is a photograph in the case where only a 345 nm ultraviolet ray is irradiated to the film fragment of the present embodiment placed on the table. It was confirmed that fragments of the film on the table and fine fragments of the film emitted red light as in the case of the above photo.

The upper left photograph in FIG. 6 is a photograph showing a state in which the organic / metal hybrid polymer film of the example of the present invention before being exposed to HCl gas was irradiated with ultraviolet rays of 345 nm, and strong red fluorescence was observed. The upper right photograph shows a state in which this film was exposed to HCl gas and then subjected to similar ultraviolet irradiation. After exposure to HCl by placing it in an HCl gas atmosphere with an HCl solution in advance for 5 to 10 seconds, almost no fluorescence was observed. By exposing the film having lost fluorescence in this way to the vapor in a triethylamine atmosphere with a triethylamine (Et ₃ N) solution for 30 to 60 seconds, the fluorescence was restored as shown in the upper left photo. .

  The lower left graph of FIG. 6 shows a fluorescence spectrum when the above-described fluorescence disappearance-revival is repeated five times. That is, in this graph, as a curve of a spectrum in a state where strong fluorescence is emitted by ultraviolet irradiation at 345 nm, one curve before exposure to HCl vapor and five curves of the graph at the time of five revival are shown. For convenience, six lines are shown, and five lines corresponding to each of the five fluorescence disappearance states are shown as a spectrum curve in a state where almost no fluorescence is emitted even when the same ultraviolet irradiation is performed. The graph on the lower right shows the intensity at 612 nm of the fluorescence emitted when the same ultraviolet irradiation is performed before the HCl vapor exposure, at the time of disappearance of the fluorescence five times, and at the time of the five times of the trend recovery. Yes. From these graphs, it was confirmed that by repeating the HCl treatment and the triethylamine treatment, the fluorescence intensity could be reduced reversibly, although the fluorescence intensity tended to decrease somewhat.

  The organic / metal hybrid polymer of the present invention not only has fluorescence, but also has a unique property that has not been known so far that it can be repeatedly lost and revived with a simple treatment. Various applications to display devices, storage devices, sensors, etc. are expected.

International Publication No. 2007/049371 JP2007-1112769 JP2007-112957A International Publication No. 2008/081762 JP2008-162967 JP2008-162976 JP2008-162979 International Publication No. 2008/143324 JP 2009-223159 A JP 2009-265437 A

Claims (7)

An organic / fluorescent metal hybrid polymer having a structure represented by the following general formula, comprising a ligand of a bisterpyridine derivative, a rare earth metal ion, and a counter cation.

Where L is a rare earth metal ion ;
Substituents A1 to A4 are carboxyl groups and substituents represented by the following structural formula

And at least one of the substituents A1 and A2 and at least one of the substituents A3 and A4 is a carboxyl group,
X is a spacer having at least one aromatic ring between two terpyridyl substituents, and any structure selected from the group of the following structures (1), (2) and (3): Have.
(1) A structure represented by the following chemical formula.

However, R is a substituent represented by the following structural formula having a PEG group in the side chain.

(2) A structure represented by any of the following chemical formulas.

(3) A structure represented by any of the following chemical formulas.

However, in structures (2) and (3), R _{1 to} R ₆ are each independently selected from the group consisting of a plurality of structures represented by R, and R ₇ and R ₈ are R ₇ and R _8. The plurality of R ″ are selected independently from each other from the group consisting of a plurality of structures shown as the option of the above, and the plurality of R ″ are independently selected from the group consisting of the plurality of structures shown as the option of the R ″. X ≦ 100,000 and 1 ≦ n ≦ 20. The organic / fluorescent metal hybrid polymer according to claim 1, wherein n in the general formula is 500 or less . The counter cation is selected from the group consisting of Na, K, HN (R) ₃ , N (R) ₄ , where R is
-CH ₃
- (CH _{2) n} CH _{3
-CH 2 CH 2 O (CH 2} CH 2) n CH 3
(However, 1 ≦ n ≦ 5)
The organic / fluorescent metal hybrid polymer according to claim 1 or 2 , selected from the group consisting of: The organic / fluorescent metal hybrid polymer according to any one of claims 1 to 3, wherein the rare earth metal is Eu or Tb . 5. The organic / fluorescent metal hybrid polymer according to any one of claims 1 to 4 , which loses fluorescence upon exposure to acid vapor . 6. The organic / fluorescent metal hybrid polymer of claim 5 , wherein the lost fluorescence is restored upon exposure to amines or ammonia vapors . A ligand composed of a bisterpyridine derivative having a structure represented by the following general formula.

However, the substituents A to A4 are carboxyl groups or substituents represented by the following structural formulas

And at least one of the substituents A1 and A2 and at least one of the substituents A3 and A4 is a carboxyl group,
X is a spacer having at least one aromatic ring between two terpyridyl substituents, and any structure selected from the group of the following structures (1), (2) and (3): Have.
(1) A structure represented by the following chemical formula.

( Where R is a substituent represented by the following structural formula having a PEG group in the side chain)

(2) A structure represented by any of the following chemical formulas.

(3) A structure represented by any of the following chemical formulas.

However, in structures (2) and (3), R _{1 to} R ₆ are each independently selected from the group consisting of a plurality of structures represented by R, and R ₇ and R ₈ are R ₇ and R _8. The plurality of R ″ are selected independently from each other from the group consisting of a plurality of structures shown as the option of the above, and the plurality of R ″ are independently selected from the group consisting of the plurality of structures shown as the option of the R ″. X ≦ 100,000 and 1 ≦ n ≦ 20.