JP5888649B2 - Water detection reagent and method for quantitatively measuring water concentration in aprotic polar solvent - Google Patents

Description

  The present invention relates to a water detection reagent for detecting water and a method for measuring the concentration of water using the same, and more specifically, a water detection reagent for detecting water in an aprotic polar solvent, and The present invention relates to a method for quantitatively measuring the concentration of water in an aprotic polar solvent.

Quantitative analysis of water (H ₂ O) in organic solvents, especially aprotic polar solvents, is important. Aprotic polar solvents are used as solvents for flammable reagents such as alkali metals, organolithiums, Grignard reagents, etc., but are easily miscible with water. Therefore, when an aprotic polar solvent is used as a solvent for a flammable reagent, it is necessary that water is not mixed in the aprotic solvent for safety.

The Karl Fischer method is known as a method for detecting water mixed in an aprotic polar solvent. The Karl Fischer method is a method of detection by a coulometric titration method or a volumetric titration method using a Karl Fischer reagent that reacts selectively and quantitatively with water. According to the Karl Fischer method, a H ₂ O concentration of up to 1 ppm can be detected, but either a coulometric titration method or a volumetric titration method requires a dedicated device, and is not versatile. Further, the Karl Fischer reagent to be used is a toxic reagent containing methanol, iodine, sulfur dioxide and the like, and is harmful to the human body.

Another method for detecting water mixed in an aprotic polar solvent is to use a dye molecule. In response to changes in the H ₂ O concentration, the fluorescence of the dye is suppressed or the fluorescence spectrum of the dye changes. When such a dye molecule is used, an H ₂ O concentration of about 20 ppm can be detected. However, the accuracy of fluorescence spectrum analysis is affected by various factors such as quencher, photobleaching, concentration, temperature and the like.

  Therefore, it is desirable to have a reagent that is non-toxic, excellent in versatility, and capable of detecting water in an aprotic polar solvent stably and simply. It would also be desirable if there was a method that could use such a reagent and quantitatively measure the concentration of water in the aprotic polar solvent.

  An object of the present invention is to provide a water detection reagent that easily detects water in an aprotic polar solvent, and a method for quantitatively measuring the concentration of water in the aprotic polar solvent using the same. It is.

A water detection reagent for detecting water in an aprotic polar solvent according to the present invention comprises an oxoporphyrinogen represented by formula (1),

Here, R1 is hydrogen, and R2 is an organic functional group bonded through hydrogen or a benzyl group, thereby achieving the above-described problem.
The aprotic polar solvent may be an organic solvent selected from the group consisting of tetrahydrofuran, dioxane, and dimethylformamide.
The organic functional group may be an anionic organic functional group.
The anionic organic functional group may contain at least one salt selected from the group consisting of carboxylate, phosphate and sulfonate.
R2 may be an organic functional group bonded through a benzyl group selected from the group consisting of formula (2).

The method for measuring the concentration of water in an aprotic polar solvent according to the present invention is a step of adding a water detection reagent to the aprotic polar solvent to prepare a test solution, wherein the water detection reagent comprises: Consisting of oxoporphyrinogen represented by formula (1),

Here, R1 is hydrogen, R2 is an organic functional group bonded through hydrogen or a benzyl group, a step of measuring an absorption spectrum of the test solution, and a concentration of water from the absorption spectrum Reading the absorbance A1 of the isosbestic point that is not affected by the absorbance and the absorbance A2 of the absorption peak affected by the concentration of water, calculating the ratio A2 / A1 from the absorbances A1 and A2, and the absorbance A1 and the absorbance Determining the concentration of water in the test solution based on the ratio A2 / A1, thereby achieving the above object.
The determining step may use a calibration diagram showing a relationship between the concentration of water in the aprotic polar solvent, the absorbance A1, and the ratio A2 / A1 using the water detection reagent.
Prior to the determining step, the method includes a step of creating a calibration diagram showing the relationship between the concentration of water in the aprotic polar solvent by the water detection reagent, the absorbance A1, and the ratio A2 / A1. May be.
The measuring step may be performed in a temperature range of 10 ° C to 30 ° C.

The water detection reagent for detecting water in the aprotic polar solvent according to the present invention comprises oxoporphyrinogen (OxP) represented by the above formula (1). Thereby, OxP represented by the formula (1) easily hydrogen bonds with water present in the aprotic polar solvent, thereby changing the absorption spectrum of OxP in the aprotic polar solvent. By utilizing such a change in absorption spectrum, the amount of water in the aprotic polar solvent can be determined. OxP is stable because it does not undergo chemical changes or photobleaching. In addition, no significant toxicity has been found, and no harm to the human body has been reported. Furthermore, since OxP is reusable, it is environmentally friendly.

  Further, according to the method for determining the water concentration according to the present invention, the step of measuring the absorption spectrum of the aprotic polar solvent containing OxP, the absorbance A1 of the isosbestic point not affected by the water concentration, and Reading the absorbance A2 of the absorption peak affected by the water concentration, calculating the ratio A2 / A1, and determining the water concentration based on the absorbance A1 and the ratio A2 / A1. Since it is only necessary to measure the absorption spectrum, it does not require a dedicated device and is excellent in versatility. Moreover, the concentration of water can be determined with high accuracy and simplicity simply by obtaining the absorbance A1 and the ratio A2 / A1.

Schematic diagram showing oxoporphyrinogen constituting the reagent for water detection according to the present invention The figure which shows typically the change of the absorption spectrum with respect to the water of the reagent for water detection by this invention Flowchart showing steps for measuring the concentration of water in an aprotic polar solvent using the water detection reagent according to the present invention. FIG. 3 shows an exemplary calibration diagram using a water detection reagent according to the present invention. The figure which shows the change by the presence or absence of the water in THF which added OxP1 by Example 1. FIG. 5 shows the change in absorption spectrum of OxP1 in THF with various water concentrations according to Example 1. The figure which shows the result of the titration experiment of THF which added OxP1 by Example 1. The figure which shows the result of the titration experiment of THF which added OxP2 by Example 2. The figure which shows the result of the titration experiment of THF which added OxP3 by Example 3. The figure which shows the result of the titration experiment of THF which added OxP4 by Example 4. The figure which shows the result of the titration experiment of THF which added OxP5 by Example 5. The figure which shows the result of the titration experiment of THF which added OxP6 by Example 6. The figure which shows the result of the titration experiment of THF which added OxP7 by the comparative example 7. The figure which shows the result of the titration experiment of THF which added OxP1 and BHT by Example 8. The figure which shows the temperature dependence of the absorption spectrum of THF which added OxP1 by Example 1. The figure which shows the absorption spectrum (A) at the time of repeatedly using OxP1 by Example 1, and the change (B) of a light absorbency. Calibration diagram of OxP1 according to Example 1 The figure which shows a mode that the water in the various solvent which added various OxP of an Example and Comparative Examples 9-12 is detected.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same reference number is attached | subjected to the same component and the description is abbreviate | omitted.

  FIG. 1 is a schematic diagram showing oxoporphyrinogen constituting the water detection reagent according to the present invention.

A water detection reagent according to the present invention is a water detection reagent for detecting water in an aprotic polar solvent, and is an oxoporphyrinogen represented by the formula (1) (hereinafter simply referred to as OxP) 100 ( 1).


Here, R1 is hydrogen, and R2 is an organic functional group bonded through hydrogen or a benzyl group.

  The aprotic polar solvent is not particularly limited as long as it is a solvent having no proton donating property, and is preferably a solvent selected from the group consisting of tetrahydrofuran, dioxane and dimethylformamide. If these solvents are used, it is possible to reliably detect mixed water using the water detection reagent of the present invention.

  When R2 is an organic functional group bonded via a benzyl group, preferably R2 is an anionic functional group. If R2 is an anionic functional group, the sensitivity of OxP100 to water can be increased, so that water can be detected with high accuracy.

  More preferably, R2 is an anionic functional group selected from the group consisting of carboxylate, phosphate and sulfonate. These functional groups can increase the sensitivity of OxP100 to water.

When R2 is an organic functional group bonded through a benzyl group, for example, it is an organic functional group bonded through a benzyl group selected from the group consisting of formula (2). With these organic functional groups, OxP100 has high sensitivity to water. In formula (2), the alkyl group is, for example, a methyl group, but is not limited thereto. The alkyl group may be a linear alkyl group such as n-propyl group or n-dodecyl group, a branched alkyl group such as 2-ethylhexyl group, etc., and those skilled in the art will appropriately select an alkyl group. obtain.

The water detection reagent according to the present invention comprises OxP100 as described above. OxP100 can bind to one H ₂ O molecule in pyrrole NH110 and up to four H ₂ O molecules in quinoids C═O120, 130, 140 and 150 to form hydrogen bonds. By forming this hydrogen bond, the absorption spectrum of OxP in the aprotic polar solvent changes, so that water mixed with the aprotic polar solvent can be detected. Note that if even one hydrogen bond is formed on the quinoid C = O side, the absorption spectrum changes, so even a minute amount of water (concentration) can be detected.

  Next, changes in the absorption spectrum of the water detection reagent of the present invention will be described.

  FIG. 2 is a diagram schematically showing changes in the absorption spectrum of the water detection reagent according to the present invention with respect to water.

  2 is an absorption spectrum of a water detection reagent in an anhydrous aprotic polar solvent, and an absorption spectrum 220 is an absorption spectrum of the water detection reagent in an aprotic polar solvent mixed with water. is there.

As shown in FIG. 2, the absorption spectrum of the water detection reagent of the present invention clearly changes in the shape of the absorption spectrum depending on the presence of water and the concentration of water. As described above, this is because OxP100 constituting the water detection reagent of the present invention binds to H ₂ O molecules to form hydrogen bonds.

  In FIG. 2, the peak P1 is an isosbestic point that is not affected by water (water content). The absorbance of the peaks P2 and P3 is affected by the concentration of water and changes. Specifically, the absorbance at peak P2 is reduced by the presence of water, while the absorbance at peak P3 is increased by the presence of water.

  The degree of change in the absorbance of the absorption spectrum of such a water detection reagent depends on the concentration of water in the aprotic polar solvent, but the tendency of the change does not change. Therefore, by utilizing these changes in peak intensity, not only the presence or absence of water in the aprotic polar solvent, but also the quantitative analysis of the concentration of water is possible. Further, when the concentration of water in the aprotic polar solvent is high, the change in peak intensity becomes extremely remarkable, so that it can be visually determined that the aprotic polar solvent contains water.

  OxP constituting the water detection reagent of the present invention has not been found to be significantly toxic and has not been reported to be harmful to the human body. Further, since no chemical change or photobleaching occurs, water in the aprotic polar solvent can be detected stably. Furthermore, since OxP is reusable, it is environmentally friendly.

  The absorption spectrum is preferably an ultraviolet-visible absorption spectrum. This is because OxP that constitutes the water detection reagent of the present invention surely has a peak that is influenced and not affected by the concentration of water in the ultraviolet-visible region.

  Next, a method for quantitatively measuring the concentration of water in the aprotic polar solvent using the water detection reagent of the present invention will be described with reference to FIGS.

  FIG. 3 is a flowchart showing steps of measuring the concentration of water in the aprotic polar solvent using the water detection reagent according to the present invention.

  Step 310: A reagent for water detection is added to an aprotic polar solvent to prepare a test solution. Here, since the reagent for water detection consists of OxP shown by Formula (1) mentioned above, description is abbreviate | omitted. There is no particular need to adjust the concentration of the test solution.

  Step 320: Measure the absorption spectrum of the test solution. The absorption spectrum is preferably measured in the ultraviolet-visible region, and an ordinary measuring device can be used. The measurement is preferably performed in a temperature range of 10 ° C to 30 ° C. In this temperature range, the absorption spectrum hardly depends on the temperature, so that an accurate concentration can be obtained.

  Step S330: Read the absorbance A1 of the isosbestic point not affected by the water concentration and the absorbance A2 of the absorption peak P2 affected by the water concentration from the absorption spectrum. Here, it is assumed that the measured absorption spectrum of the test solution is an absorption spectrum 220 (FIG. 2). The absorbance A3 of the absorption peak P3 affected by the water concentration may be read. However, when there are a plurality of absorption peaks affected by the water concentration, the absorption peak having the maximum absorbance is not affected by the temperature. It is good to adopt. Thereby, the density | concentration of water can be calculated | required with high precision.

  Step S340: Calculate the absorbance A1 and the ratio A2 / A1. In the absorption spectrum 220, the isosbestic point that is not affected by the concentration of water is P1, and its absorbance is A1. On the other hand, in the absorption spectrum 220, the absorption peak affected by the concentration of water is P2, and its absorbance is A2.

  Step S350: The concentration of water in the test solution is determined based on the absorbance A1 and the ratio A2 / A1. If the reagent for water detection of this invention is used, since it has predetermined relationship (after-mentioned) between the light absorbency A1, ratio A2 / A1, and the density | concentration of water, the density | concentration of water can be determined.

  Preferably, in step S350, a calibration diagram showing the relationship between the absorbance A1, the ratio A2 / A1, and the water concentration is used. Thereby, the density | concentration of water can be determined simply and instantly. For example, an electronic computer storing calibration diagram data may be used.

  FIG. 4 shows an exemplary calibration diagram using the water detection reagent according to the present invention.

What is necessary is just to obtain | require a calibration figure as follows.
A2 = A2 (p) × c ′ / c ₀ (f1)
A1 = A1 ₀ × c ′ / c ₀ (f2)
Here, A1 and A2 are the absorbances of the isosbestic point P1 and the absorption peak P2 obtained from the absorption spectrum of FIG. A1 ₀ is the absorbance of the isosbestic point P1 obtained in titration experiments. c ₀ is the concentration of OxP obtained in the titration experiment, and c ′ is the concentration of OxP in the test solution. A2 (p) is a bond isotherm calculated from the following equation, represented by the independent variable p, and is the concentration of water in the aprotic polar solvent (unit: ppm).


Here, ΔA2 is the change in absorbance at the absorption peak P2 of OxP per one water molecule bond, B is the absorbance at the absorption peak P2 of OxP without water molecules, and βi is the binding of the whole system It is a constant.

Expressions (f1) and (f2) can be rewritten as follows.
A2 / A1 = A2 (p) / A1 ₀ (f3)
Here, A2 / A1 is the ratio of step S340 described above. Therefore, it can be seen that the two parameters of the absorbance A1 and the ratio A2 / A1 at the isosbestic point P1 in step S350 serve as a reference for obtaining the water concentration. As described above, the calibration diagram is created based on the calibration curve measurement in various combinations of the absorbance A1 and the ratio A2 / A1 according to the equation (f3).

  In FIG. 4, a calibration diagram divided into eight water concentration regions a to h is shown. A predetermined water concentration range is assigned to each region. It can be seen that the greater the ratio A2 / A1, the lower the concentration of water, and the higher the value of A1, the higher the concentration of the water detection reagent of the present invention.

  The concentration of water in the aprotic solvent can be determined by simply plotting the absorbance A1 and the ratio A2 / A1 calculated from the absorption spectrum and plotting them in a calibration diagram and seeing which region they belong to.

  Such a calibration diagram may be created using the above equation prior to step S350.

  The present invention will now be described in detail using specific examples, but it should be noted that the present invention is not limited to these examples.

<Example 1>
Example 1 is a water detection reagent according to the present invention. In the formula (1), R1 is hydrogen (H), R2 is carboxybenzyl sodium which is an anionic functional group as an organic functional group via a benzyl group. _{there, N 21,} N ₂₃ - bis (4-carboxybenzyl) 5,10,15,20 (3,5-di -tert- butyl-4-oxo-2,5-cyclohexadienyl Eni isopropylidene) porphyrin Norogen disodium salt (hereinafter simply referred to as OxP1). Tetrahydrofuran (THF) was used as an aprotic polar solvent.

For the production of OxP1, 5,10,15,20- (3,5-di-tert-butyl-4-oxo-2,5-cyclohexadieny, wherein R1 and R2 are both hydrogen in formula (1) Redene) porphyrinogen (hereinafter simply referred to as OxP2) was used as the starting material. OxP2 is described in J.P. P. Hill et al., Eur. J. et al. Org. Chem. , 2005, 2893. Subsequently, N ₂₁ , N ₂₃ -bis (4- (methoxycarbonyl) benzyl) -5,10, was obtained by N-alkylation of OxP2 using methyl-4- (bromomethyl) benzoate (Tokyo Chemical Industry Co., Ltd.). 15,20- (3,5-Di-tert-butyl-4-oxo-2,5-cyclohexadienylidene) porphyrinogen (hereinafter simply referred to as OxP4) was prepared.

  It was identified using nuclear magnetic resonance (NMR spectroscopy) that the obtained solid powder was OxP4. The apparatus used was an AL300 BX spectrometer (JEOL, Japan), and the measurement was performed at 25 ° C. Moreover, the mass spectrum was measured using Shimadzu-Kratos Axima CFR + MALDI-TOF mass spectrometer. Disranol was used for the matrix. These results are shown.

¹ H-NMR (CDCl ₃ , 300 MHz): δ = 9.66 (s, 2H, NH), 7.82 (d, 4H, Ar—H), 7.56 (s, 4H, hemi-quinone-H ), 7.03 (s, 4H, hemi-quinone-H), 6.89 (s, 4H, pyrrole β-H), 6.82 (d, 4H, Ar-H), 6.57 (s, 4H, pyrrole β-H), 4.56 (s, 4H, benzyl-CH ₂ ), 3.84 (s, 6H, COOCH ₃ ), 1.34 (s, 36H, tert-butyl), 1.21 (S, 36H, tert-butyl) ppm
_{MALDI-TOF-MS: C 94} H 108 N 4 theory 1421.82m / z of _{O 8,} experimental values ^{1423.31m / z [M + H]} +

Next, OxP4 (20 mg) was dissolved in tetrahydrofuran (THF, super-dehydration, stabilizer not used, H ₂ O <0.001%, Wako Pure Chemical Industries, Ltd.) (50 mL), methanol (10 mL) and KOH (100 mg). ) In H ₂ O (5 mL) was added. The mixed solution was refluxed for 24 hours and cooled to room temperature. The organic solvent was evaporated under reduced pressure. The obtained purple powder was dissolved in dichloromethane, washed with 0.1 M HCl aqueous solution, and washed twice with pure water. Dichloromethane was evaporated and the resulting solid was dried overnight under vacuum. Thus, from OxP4, N ₂₁ , N ₂₃ -di (4-carboxybenzyl) -5,10,15,20- (3 in which R1 is hydrogen and R2 is carboxybenzyl in formula (1) , 5-Di-tert-butyl-4-oxo-2,5-cyclohexadienylidene) porphyrinogen (hereinafter simply referred to as OxP5).

  It was identified by NMR spectroscopy that the obtained solid powder was OxP5, and a mass spectrum was measured. These results are shown.

¹ H-NMR (CDCl ₃ -CD ₃ OD, 300 MHz): δ = 7.85 (d, 4H, Ar—H), 7.62 (s, 4H, hemi-quinone-H), 7.13 (s , 4H, hemi-quinone-H), 6.95 (s, 4H, pyrrole β-H), 6.83 (d, 4H, Ar—H), 6.71 (s, 4H, pyrrole β-H) , 4.56 (s, 4H, benzyl _{-CH 2), 1.23 (m,} 72H, tert- butyl) ppm
MALDI-TOF-MS: Theoretical value of C ₉₂ H ₁₀₄ N ₄ O ₈ of 1393.79 m / z, experimental value of 1394.94 m / z [M + H] ⁺ .

OxP5 (5 mg) was then dissolved in THF (20 mL) and a mixture of methanol (5 mL) and H ₂ O (2 mL) in which NaOH (5 mg) was dissolved was added. The mixed solution was stirred at room temperature and the solvent was evaporated under reduced pressure. The resulting purple powder was washed several times with distilled water on a 0.22 μm PVDF filter. The residue was dissolved in THF and the solvent was evaporated under reduced pressure and dried overnight under vacuum. In this way, OxP1 was produced from OxP5.

  It was identified by NMR spectroscopy that the finally obtained solid powder was OxP1, and the mass spectrum was measured. These results are shown.

¹ H-NMR (CDCl ₃ CD ₃ OD, 300 MHz): δ = 7.73 (d, 4H, Ar—H), 7.67 (s, 4H, hemi-quinone-H), 7.30 (s, 4H, hemi-quinone-H), 6.98 (s, 4H, pyrrole β-H), 6.75 (d, 4H, Ar—H), 6.61 (s, 4H, pyrrole β-H), 4.60 (s, 4H, benzyl _{-CH 2), 1.33 (s,} 36H, tert- butyl), 1.25 (s, 36H, tert- butyl) ppm
_{MALDI-TOF-MS: C 92} H 102 N 4 O 8 Na 2 of theory 1436.75m / z, the experimental value 1395.10m / z [M-2Na + 3H] +

OxP1 (0.1 mg) was added as an aprotic polar solvent to anhydrous THF (10 mL) immediately after purchase, and the appearance was observed. Next, H ₂ O was added thereto, and the appearance was observed. These results are shown in FIG. 5 and will be described later.

Next, in order to confirm the response of OxP1 to water and the water concentration, and to determine the binding constant and sensitivity of OxP1 to water, a titration experiment using an absorption spectrum was performed. A THF solution (3.5 × 10 ⁻⁶ , 3 mL) obtained by adding OxP1 to anhydrous THF (H ₂ O <10 ppm) immediately after purchase was placed in a 1 cm quartz cell, and a screw cap was applied. The absorption spectrum of this was measured.

  Absorption spectra were measured for a wavelength range of 300 nm to 900 nm using a Shimadzu UV-3600 UV-vis-NIR spectrophotometer at 25 ° C. Next, ultrapure water was added to the quartz cell using a microsyringe and shaken well, and then the absorption spectrum was measured. Here, the ultrapure water added to anhydrous THF is distilled using Yamato Kagaku Auto Still WG220 and deionized using Milli-Q Lab manufactured by Millipore. The concentration of water in THF was changed to a range of 0 ppm to 33000 ppm, and absorption spectra were measured at various concentrations (hereinafter also referred to as titration experiments).

  The absorption spectrum of OxP1 in a THF solution in which the concentration of water in THF is 37 ppm, 370 ppm, 3700 ppm and 33000 ppm is shown in FIG. 6 and will be described later. Binding constants and sensitivities were calculated from the absorption spectra of OxP1 in all THF solutions with the concentration of water in THF ranging from 0 ppm to 33000 ppm. The results are shown in FIG.

Next, the temperature dependence of OxP1 was examined. A THF solution in which the concentration of water in THF was anhydrous (H ₂ O <10 ppm), 3700 ppm, and 33000 ppm was held at temperatures of 10 ° C., 25 ° C., 40 ° C., and 55 ° C., and respective absorption spectra were measured. . The results are shown in FIG. 15 and will be described later.

Next, the repeated use of OxP1 was examined. Ultrapure water was added to a THF solution in which the concentration of water in THF was anhydrous (H ₂ O <10 ppm), and the concentration of water was adjusted to 5000 ppm. Next, the THF solution to which ultrapure water was added was dried in vacuum for 1 hour to remove water to obtain an anhydrous OxP1 solid, and then dissolved in an anhydrous (H ₂ O <10 ppm) THF solution did. The process of adding ultrapure water, vacuum drying, and dissolving in anhydrous (H ₂ O <10 ppm) in THF solution was repeated three times. The absorption spectrum of OxP1 in the THF solution was measured at the time of addition of ultrapure water and vacuum drying in each process. The results are shown in FIG. 16 and will be described later.

Next, a calibration diagram was created using OxP1. In the above formulas (f1) to (f3), A1 is absorbance at a wavelength of 535 nm, A2 is absorbance at a wavelength of 507 nm, and a known concentration of water in THF (less than 10 ppm, 50 ppm, 200 ppm, 500 ppm, 1000 ppm). , 2000 ppm, 3000 ppm and 5000 ppm). The molar extinction coefficient ε of OxP1 was 141150 Lmol ⁻¹ cm ⁻¹ . The results are shown in FIG. 17 and will be described later.

<Example 2>
In Example 2, as the water detection reagent of the present invention, in formula (1), R1 and R2 are both hydrogen (H), 5,10,15,20- (3,5-di-tert- Butyl-4-oxo-2,5-cyclohexadienylidene) porphyrinogen (same as OxP2 described above). OxP2 is a material used as a starting material for producing OxP1 of Example 1. Moreover, THF was used as an aprotic polar solvent.

  In the same manner as in Example 1, in order to confirm the response of OxP2 to water and water concentration, and to determine the binding constant and sensitivity of OxP2 to water, a titration experiment using an absorption spectrum was performed. The results are shown in FIG. 8 and will be described later.

<Example 3>
Example 3 shows N ₂₁ , N ₂₃ -bis (4-bromobenzyl) as a reagent for detecting water according to the present invention, wherein R 1 is hydrogen (H) and R 2 is benzyl bromide in formula (1). -5,10,15,20- (3,5-di-tert-butyl-4-oxo-2,5-cyclohexadienylidene) porphyrinogen (hereinafter simply referred to as OxP3). Moreover, THF was used as an aprotic polar solvent.

  OxP3 was produced by N-alkylation of OxP2 using 4-bromobenzyl bromide (Tokyo Chemical Industry Co., Ltd.). The obtained solid powder was identified as OxP3 by NMR spectroscopy, and the mass spectrum was measured. These results are shown.

¹ H-NMR (THF-d ₈ , 300 MHz): δ = 9.81 (s, 2H, NH), 7.65 (d, 4H, hemi-quinone-H), 7.28 (d, 4H, Ar) -H), 7.18 (d, 4H, hemi-quinone-H), 7.00 (d, 4H, pyrrole β-H), 6.71 (d, 4H, Ar-H), 6.69 ( s, 4H, pyrrole β-H), 4.52 (s, 4H, benzyl-CH ₂ ), 1.34 (s, 36H, tert-butyl), 1.26 (s, 36H, tert-butyl) ppm
MALDI-TOF-MS: Theoretical value of C ₉₀ H ₁₀₂ Br ₂ N ₄ O ₄ 1462.62 m / z, experimental value 1463.52 m / z [M + H] ⁺

  In the same manner as in Example 1, in order to confirm the response of OxP3 to water and water concentration, and to determine the binding constant and sensitivity of OxP3 to water, a titration experiment using an absorption spectrum was performed. The results are shown in FIG. 9 and will be described later.

<Example 4>
In Example 4, N ₂₁ , N ₂₃ -bis (4- (methoxycarbonyl) is used as the water detection reagent of the present invention, in which R1 is hydrogen (H) and R2 is methoxycarbonylbenzyl in formula (1). ) Benzyl) -5,10,15,20- (3,5-di-tert-butyl-4-oxo-2,5-cyclohexadienylidene) porphyrinogen (same as OxP4 described above). OxP4 is a material used to produce OxP1 of Example 1. Moreover, THF was used as an aprotic polar solvent.

  In the same manner as in Example 1, in order to confirm the response of OxP4 to water and water concentration, and to determine the binding constant and sensitivity of OxP4 to water, a titration experiment using an absorption spectrum was performed. The results are shown in FIG. 10 and will be described later.

<Example 5>
In Example 5, N ₂₁ , N ₂₃ -bis (4-carboxybenzyl) -5,10, in which R1 is hydrogen and R2 is carboxybenzyl in the formula (1) as the water detection reagent of the present invention. 15,20- (3,5-di-tert-butyl-4-oxo-2,5-cyclohexadienylidene) porphyrinogen (same as OxP5 described above). OxP5 is a material used to produce OxP1 of Example 1. Moreover, THF was used as an aprotic polar solvent.

  In the same manner as in Example 1, in order to confirm the response of OxP5 to water and water concentration, and to determine the binding constant and sensitivity of OxP5 to water, a titration experiment using an absorption spectrum was performed. The results are shown in FIG. 11 and will be described later.

<Example 6>
Example 6 shows N ₂₁ , N ₂₃ -bis (2-naphthylmethyl)-in which R1 is hydrogen (H) and R2 is naphthylmethyl in the formula (1) as a water detection reagent of the present invention. It relates to 5,10,15,20- (3,5-di-tert-butyl-4-oxo-2,5-cyclohexadienylidene) porphyrinogen (hereinafter simply referred to as OxP6). OxP6 is described in J. Org. P. Hill et al., Eur. J. et al. Org. Chem. , 2005, 2893. Moreover, THF was used as an aprotic polar solvent.

  In the same manner as in Example 1, in order to confirm the response of OxP6 to water and water concentration, and to determine the binding constant and sensitivity of OxP6 to water, a titration experiment using an absorption spectrum was performed. The results are shown in FIG. 12 and will be described later.

<Comparative Example 7>
In Comparative Example 7, N ₂₁ , N ₂₂ , N ₂₃ , N ₂₄ -tetrakis (4- (methoxycarbonyl) benzyl) -5, 10, 15 in which R 1 and R 2 are methoxycarbonylbenzyl in formula (1) , 20- (3,5-di-tert-butyl-4-oxo-2,5-cyclohexadienylidene) porphyrinogen (hereinafter simply referred to as OxP7). Moreover, THF was used as an aprotic polar solvent.

  OxP7 was produced by N-alkylation of OxP2 using methyl-4- (bromomethyl) benzoate (Tokyo Chemical Industry Co., Ltd.). The obtained solid powder was identified as OxP7 by NMR spectroscopy, and the mass spectrum was measured. These results are shown.

¹ H-NMR (CDCl ₃ , 300 MHz): δ = 7.93 (d, 8H, Ar—H), 7.29 (s, 8H, hemi-quinone-H), 6.77 (d, 8H, Ar) -H), 6.75 (s, 8H , pyrrole β-H), 4.64 (s , 8H, benzyl _{-CH 2), 3.93 (s,} 12H, COOCH 3), 1.31 (s, 72H, tert-butyl) ppm
MALDI-TOF-MS: Theoretical value 1717.92 m / z of C ₁₁₂ H ₁₂₄ N ₄ O ₁₂ , experimental value 1718.83 m / z [M + H] ⁺

  In the same manner as in Example 1, in order to confirm the response of OxP7 to water and water concentration, and to determine the binding constant and sensitivity of OxP7 to water, a titration experiment using an absorption spectrum was performed. The results are shown in FIG. 13 and will be described later.

<Example 8>
In Example 8, the influence of an inhibitor such as an antioxidant in the water detection reagent of the present invention was examined. A titration experiment using an absorption spectrum was conducted in the same manner as in Example 1 by adding 600 ppm of 3,5-di-tert-butyl-4-hydroxytoluene (BHT) as an inhibitor to OxP1 produced in Example 1. It was. The results are shown in FIG. 14 and will be described later.

<Example 9>
Example 9 is the same as Example 1 except that 1,4-dioxane was used in place of THF as the aprotic polar solvent. OxP1 (0.1 mg) was added to 1,4-dioxane (10 mL) immediately after purchase as an aprotic polar solvent, and the appearance was observed. Then, it was put into H ₂ O and the appearance was observed. These results are shown in FIG. 18 and will be described later.

<Example 10>
Example 10 is the same as Example 1 except that N, N-dimethylformamide (Tokyo Chemical Industry Co., Ltd.) was used instead of THF as the aprotic polar solvent. OxP1 (0.1 mg) was added to N, N-dimethylformamide (10 mL) immediately after purchase as an aprotic polar solvent, and the appearance was observed. Then, it was put into H ₂ O and the appearance was observed. These results are shown in FIG. 18 and will be described later.

<Comparative Example 11>
Comparative Example 11 is the same as Example 1 except that ethanol is used instead of THF. OxP1 (0.1 mg) was added to ethanol (10 mL), and the appearance was observed. Then, it was put into H ₂ O and the appearance was observed. These results are shown in FIG. 18 and will be described later.

<Comparative Example 12>
Comparative Example 12 is the same as Example 2 except that dichloromethane was used instead of THF. OxP2 (0.1 mg) was added to dichloromethane (10 mL), and the appearance was observed. Then, it was put into H ₂ O and the appearance was observed. These results are shown in FIG. 18 and will be described later.

For simplicity, the experimental conditions of the above Examples and Comparative Examples 1-12 are summarized in Table 1.

  FIG. 5 is a diagram showing changes due to the presence or absence of water in THF to which OxP1 according to Example 1 was added.

  FIG. 5A shows the state of anhydrous THF to which OxP1 has been added, and FIG. 5B shows the state of water-containing THF to which OxP1 has been added. FIG. 5 shows a black-and-white photograph. Actually, anhydrous THF exhibited a reddish purple color, but hydrous THF exhibited a blue-purple color. Similarly, similar results were obtained in Examples 2 to 6. From this, it was shown that OxP can detect water in an aprotic polar solvent, and it was confirmed that it can constitute a water detection reagent. Further, it was found that the presence or absence of water in the aprotic polar solvent can be visually determined using the water detection reagent comprising OxP of the present invention.

  6 is a graph showing changes in the absorption spectrum of OxP1 in THF having various water concentrations according to Example 1. FIG.

  According to FIG. 6, the absorbance of the absorption peak at a wavelength of 507 nm decreased as the concentration of water in THF increased. On the other hand, the absorbance of absorption peaks at wavelengths of 600 nm and 750 nm increased as the concentration of water in THF increased. From this, it was found that the absorption spectrum of the water detection reagent (OxP) of the present invention changes depending on the concentration of water in the aprotic polar solvent. Moreover, the increase / decrease in the absorbance of the above-described absorption peak coincided with the observation result shown in FIG.

Further, according to the inset of FIG. 6, OxP1 responded to THF having a water concentration of 37 ppm, and the absorbance at the absorption peak at a wavelength of 507 nm decreased. From this, using the water detection reagent of the present invention, just by measuring the absorption spectrum, an anhydrous aprotic polar solvent immediately after purchase (H ₂ O concentration <50 ppm) and an old hydrous aprotic polar solvent ( H ₂ O concentration> 50 ppm) can be easily distinguished.

  FIG. 7 is a diagram showing the results of a titration experiment of THF to which OxP1 was added according to Example 1.

  FIG. 7A is a diagram showing changes in the absorption spectrum of OxP1 in THF having various water concentrations. As described in FIG. 6, the absorbance of the absorption peak at a wavelength of 507 nm decreases as the concentration of water in THF increases, and the absorbance of the absorption peak at a wavelength of 600 nm and wavelength of 750 nm increases with the concentration of water in THF. It increased as we went. The inset in FIG. 7A is an enlarged view near the isosbestic point. The absorbance at a wavelength of 535 nm was confirmed to be an isosbestic point without depending on the concentration of water in THF. From the above, it was found that the absorption peaks at wavelengths of 507 nm, 600 nm, and 750 nm are absorption peaks that are affected by the concentration of water, and the wavelength of 535 nm is an isosbestic point that is not affected by the concentration of water.

  FIG. 7B is a graph showing the dependence of the absorbance at wavelengths of 507 nm and 600 nm on the concentration of water in THF. FIG. 7C is an enlarged view of part of FIG. The binding constant of OxP1 with respect to water in THF was calculated from FIG.

  A multi-equilibrium coupling model was adopted to calculate the coupling constant. This is because the system of OxP1 and water shows negative cooperativity, and when a simple 1: 1 stoichiometric coupling model is adopted, the coupling constant depends on the wavelength of the absorption spectrum. Is not given. This indicates that there are two or more types of OxP states in the system (for example, OxP1 in which water molecules are not bound, OxP in which one water molecule is bound, OxP1 in which two water molecules are bound, etc.). . Time-dependent density functional theory (TD-DFT) calculations can show the possibility of combining multiple water molecules in an independent manner. However, the greatest change in the absorption spectrum is due to the binding of water molecules to the quinoid carbonyl group. The effect of THF (dipole moment 1.63D) as an aprotic polar solvent can affect the affinity of OxP1 for binding water molecules. Therefore, in the multiple equilibrium binding model, the binding isotherm is constructed as the average number of water molecules that bind to a single OxP1 and is represented by the following equation:

Here, the sequential coupling constant Ki is expressed as a term of the entire coupling constant.

  [W] t is the total concentration of water in THF (approximate [OxP1] << [W]), and n is the maximum number of water molecules bound to OxP1. The n value is an important variable, and may be apparent when the structure is examined. In this experiment, the least square fitting method was performed while keeping n at a minimum. In order to obtain a good fitting, the n value was always 3 or less. The bond isotherm A ([W] t) in the absorption spectrum is expressed by the following equation.

Here, ΔA is the average amount of change in absorbance of OxP1 per water molecule bond, and B is the initial absorbance of OxP1 without water molecules.

In the above equation, bond isotherms 710 and 720 were obtained using the change in absorbance at wavelengths of 507 nm and 600 nm, respectively. Coupling constants K ₁ , K ₂ and K ₃ were determined from these. The results are shown in Table 2.

  Next, the sensitivity of OxP1 to water was determined. Fittings 730 and 740 were obtained using the change in absorbance with respect to the region where the concentration of water at a wavelength of 507 nm and a wavelength of 600 nm in FIG. Sensitivity S was determined from these inclinations. The results are shown in Table 2.

FIG. 8 shows the results of a titration experiment of THF to which OxP2 was added according to Example 2.
FIG. 9 shows the results of a titration experiment of THF to which OxP3 was added according to Example 3.
10 is a graph showing the results of a titration experiment of THF to which OxP4 was added according to Example 4. FIG.
FIG. 11 shows the results of a titration experiment of THF to which OxP5 was added according to Example 5.
12 is a graph showing the results of a titration experiment of THF to which OxP6 was added according to Example 6. FIG.
FIG. 13 is a diagram showing the results of a titration experiment of THF to which OxP7 was added according to Comparative Example 7.
FIG. 14 is a view showing the results of a titration experiment of THF to which OxP1 and BHT were added according to Example 8.

  According to FIG. 8 (A), FIG. 9 (A), FIG. 10 (A), FIG. 11 (A) and FIG. 12 (A), similarly to Example 1, the absorption spectra of OxP in Examples 2-6. Changed in response to the concentration of water in the aprotic solvent. On the other hand, according to FIG. 13A, the absorption spectrum of OxP in which R1 is not hydrogen did not change in response to the concentration of water in the aprotic polar solvent. This indicates that OxP represented by the formula (1) functions as a water detection reagent.

  14A, similarly to Example 1, the absorption spectrum of OxP added with BHT of Example 8 also changed in response to the concentration of water in the aprotic polar solvent. This indicates that the sensitivity to water is not substantially affected even when OxP represented by the formula (1) is used together with an inhibitor.

In the same manner as in Example 1, the binding constants K ₁ , K _2, and K ₃ and the sensitivity S of Examples and Comparative Examples 2 to 8 were determined. In both figures, the curve that draws the curve is the bond isotherm, and the slope of the fitting straight line in the low concentration region of water is the initial sensitivity S as defined by the International Chemical Union. The results are shown in Table 2.

According to Table 2, it was found that OxP1 of Example 1 has the highest binding constant K ₁ and the largest sensitivity S. That is, OxP1 was found to be easily bonded to water molecules and highly sensitive to water. Since the coupling constants K ₂ and K ₃ are extremely small compared to the coupling constant K ₁ , OxP1 basically binds easily to a single water molecule, without binding to a plurality of water molecules, Can have high sensitivity to water.

  Comparing Example 2 with Examples 1 and 3 to 6, in Formula (1), R2 can give a larger binding constant to an organic functional group bonded via a benzyl group than to hydrogen. From this, it was found that R2 as OxP is preferably an organic functional group bonded through a benzyl group.

  Comparing Example 1 with Examples 4 and 5, in Formula (1), R2 can give a large binding constant among the organic functional groups bonded via a benzyl group. . From this, it was found that R2 as OxP has a good anionic organic functional group.

  Comparing Comparative Example 7 with Examples 1 to 6, in Formula (1), if R1 is not hydrogen, OxP hardly changes its absorption spectrum even when bound to water, and its sensitivity to water is low. I understood that. As described above, it was also confirmed here that OxP represented by the formula (1) functions as a water detection reagent.

  According to the above Examples and Comparative Examples 1 to 7, it is suggested that the coupling constant and sensitivity can be controlled by appropriately selecting R2 in Formula (1).

  When Example 1 and Example 8 were compared, it was found that even when OxP represented by the formula (1) was used together with an inhibitor, the sensitivity to water was not substantially affected. This means that the present invention can also be applied to an aprotic polar solvent containing an inhibitor.

  FIG. 15 is a diagram showing the temperature dependence of the absorption spectrum of THF to which OxP1 was added according to Example 1.

  FIG. 15A shows the temperature dependence of the absorption spectrum of OxP1 in anhydrous THF immediately after purchase, and FIG. 15B shows the temperature dependence of the absorption spectrum of OxP1 in THF having a water concentration of 3700 ppm. FIG. 15C shows the temperature dependence of the absorption spectrum of OxP1 in THF having a water concentration of 37000 ppm.

  From FIG. 15, the absorbance of the absorption peak at a wavelength of 507 nm did not show temperature dependence. On the other hand, the absorbance at the absorption peak at a wavelength of 600 nm tended to increase as the temperature increased. In particular, when the temperature exceeded 40 ° C., the change in absorbance became significant. Therefore, in order to determine the concentration of water in the aprotic polar solvent, it is desirable to use an absorption peak that does not depend on temperature. However, even if an absorption peak that depends on temperature is used, the temperature 10 It was found that there was no problem in determining the concentration of water if the temperature was measured in the temperature range of 30 ° C to 30 ° C.

  FIG. 16 is a diagram showing an absorption spectrum (A) and a change in absorbance (B) when OxP1 according to Example 1 is repeatedly used.

  The process of repeated use was in the order of anhydrous 1 → hydrous 1 → anhydrous 2 → hydrous 2 → anhydrous 3 → hydrous 3. According to FIG. 16 (A), even after repeated use, the absorption spectra of OxP1 in anhydrous THF all matched, and the absorption spectra of OxP1 in hydrous THF all matched. As shown in FIG. 16B, it was found that the change in the absorbance (wavelength 507 nm and wavelength 600 nm) of OxP1 when used repeatedly is excellent in reproducibility. From the above, the water detection reagent comprising OxP of the present invention can be used repeatedly with good reproducibility.

  FIG. 17 shows a calibration diagram of OxP1 according to Example 1.

  In FIG. 17, black circles are experimental values of less than 10 ppm, squares are experimental values of 50 ppm, triangles are experimental values of 200 ppm, diamonds are experimental values of 500 ppm, and half-black circles are 1000 ppm. The half square is the experimental value of 2000 ppm, the half triangle is the experimental value of 3000 ppm, and the half diamond is the experimental value of 5000 ppm. From the experimental results, the water concentration (ppm) region is defined as ρ <25, 25 <ρ <125, 125 <ρ <350, 350 <ρ <750, 750 <ρ <1500, 1500 <ρ <2500, 2500 <. It was possible to divide into 8 regions of ρ <4000, 4000 <ρ.

  Next, with reference to the calibration diagram of FIG. 17, the method of FIG. 3 was used to determine the concentration of water in THF that was miscible with an unknown concentration of water. A test solution was prepared by adding a water detection reagent consisting of OxP1 to THF that can contain an unknown concentration of water as an aprotic solvent (step S310 in FIG. 3). Next, the absorption spectrum of the test solution was measured (step S320 in FIG. 3). From the obtained absorption spectrum, the absorbance A1 at an absorption point not affected by the concentration of water is 0.400 (au) at a wavelength of 535 nm, and the absorbance A2 at an absorption peak affected by the concentration of water is at a wavelength of 507 nm. 0.460 (au) was read (step S330 in FIG. 3). As a result of calculating the ratio A2 / A1 from the absorbances A1 and A2, A2 / A1 was 1.15 (step S340 in FIG. 3). Based on the absorbance A1 and the ratio A2 / A1, the concentration of water in the test solution was determined (step S350 in FIG. 3). Specifically, the values of A1 and A2 / A1 were plotted in the calibration diagram of FIG. As a result, it was found that the concentration of water in the test solution was 2000 ppm.

  From the above, it was shown that if the water detection reagent comprising OxP1 of the present invention is used, it is only necessary to measure the absorption spectrum, so that a dedicated device is not required and the versatility is excellent. It was also confirmed that the concentration of water can be determined with high accuracy and simplicity simply by obtaining the absorbance A1 and the ratio A2 / A1.

  FIG. 18 is a diagram illustrating how water in various solvents to which various OxPs of Examples and Comparative Examples 9 to 12 are added is detected.

  18 (B) shows the results of Example 9, FIG. 18 (C) shows the results of Comparative Example 12, FIG. 18 (D) shows the results of Comparative Example 11, and FIG. 18 (E) shows the results of Example. FIG. 18 (A) shows the result of Example 1 and is the same as FIG. FIG. 18 is a black-and-white photograph, but in actuality, it was differently colored when anhydrous and when it contained water.

  As shown in FIG. 18B, anhydrous 1,4-dioxane exhibited a pink color, but hydrous 1,4-dioxane exhibited a reddish purple color. In FIG. 18E, anhydrous N, N-dimethylformamide was blue, but water-containing N, N-dimethylformamide was blue-purple. Although the color development varies depending on the solvent used, if the water detection reagent comprising OxP of the present invention is used, in addition to THF, water in an aprotic polar solvent such as 1,4-dioxane and N, N-dimethylformamide is used. It was confirmed that it could be detected visually.

  On the other hand, as shown in FIGS. 18C and 18D, although it is a general organic solvent, dichloromethane and ethanol which are not aprotic polar solvents did not show a color change. Although not shown, when the absorption spectra of Comparative Examples 11 and 12 were measured, it was confirmed that there was no change in the absorption spectrum for both anhydrous and water-containing products.

  From the above, it was confirmed that the water detection reagent composed of OxP represented by the formula (1) of the present invention should detect the presence or absence of water as an aprotic polar solvent.

  As described above, the water detection reagent according to the present invention is composed of OxP represented by the formula (1). OxP easily bonds with water in an aprotic polar solvent to form a hydrogen bond, so that the shape of its absorption spectrum changes. If such a water detection reagent is used, the presence or absence of water in the aprotic polar solvent can be determined only by measuring the absorption spectrum with a general-purpose absorption spectrum measuring device. Furthermore, the concentration of water in the aprotic polar solvent can be quantitatively measured only by using the absorbance in the absorption spectrum.

100 Oxoporphyrinogen (OxP)
110 pyrrole NH
120, 130, 140, 150 Quinoid C = O

Claims (9)

A water detection reagent for detecting water in an aprotic polar solvent,
Consisting of oxoporphyrinogen represented by formula (1),

Here, R1 is hydrogen, and R2 is an organic functional group bonded via hydrogen or a benzyl group.   The reagent for water detection according to claim 1, wherein the aprotic polar solvent is an organic solvent selected from the group consisting of tetrahydrofuran, dioxane and dimethylformamide.   The reagent for water detection according to claim 1, wherein the organic functional group is an anionic organic functional group.   The reagent for water detection according to claim 3, wherein the anionic organic functional group contains a salt selected from at least one selected from the group consisting of a carboxylate, a phosphate, and a sulfonate. The water detection reagent according to claim 1, wherein R2 is an organic functional group bonded through a benzyl group selected from the group consisting of formula (2).
A method for measuring the concentration of water in an aprotic polar solvent comprising:
Adding a water detection reagent to the aprotic polar solvent to prepare a test solution, the water detection reagent comprising oxoporphyrinogen represented by formula (1);


Wherein R1 is hydrogen and R2 is an organic functional group bonded via hydrogen or a benzyl group;
Measuring an absorption spectrum of the test solution;
Reading from the absorption spectrum the absorbance A1 of the isosbestic point not affected by the concentration of water and the absorbance A2 of the absorption peak affected by the concentration of water;
Calculating a ratio A2 / A1 from the absorbances A1 and A2;
Determining the concentration of water in the test solution based on the absorbance A1 and the ratio A2 / A1.   The determination step uses a calibration diagram showing a relationship between the concentration of water in the aprotic polar solvent, the absorbance A1, and the ratio A2 / A1 using the water detection reagent. The method described in 1.   Prior to the determining step, the method includes a step of creating a calibration diagram showing the relationship between the concentration of water in the aprotic polar solvent by the water detection reagent, the absorbance A1, and the ratio A2 / A1. The method according to claim 6.   The method according to claim 6, wherein the measuring step is performed in a temperature range of 10C to 30C.