JP7347125B2 - Porous coordination polymers, gas sensing materials and gas sensing sheets - Google Patents

Description

The present invention relates to a porous coordination polymer, a gas sensing material, and a gas sensing sheet.

Lithium ion secondary batteries, which have been used in a wide variety of products in recent years, have product forms such as square, cylindrical, and pouch shapes. Among these, pouch-type lithium-ion secondary batteries use a pouch-type container made of aluminum laminate film, etc., so they have the advantage of being lightweight, can be manufactured in a variety of shapes, and have a simple manufacturing process. , when the sealing of the container is insufficient or when pinholes occur in the container, cyclic carbonates such as ethylene carbonate and chains such as diethyl carbonate, which are commonly used as solvents for electrolyte solutions, may be used. There is a problem in that a portion of carbonate, etc. becomes vapor and volatilizes, which tends to leak out of the container and cause unpleasant odors and deterioration of properties.

Various methods for inspecting gas leaking from a closed container have been proposed so far, and Patent Document 1 proposes a method of detecting gas leaking using a porous coordination polymer. However, the gas detection sensitivity gradually decreased due to the influence of moisture in the atmosphere, and depending on the usage environment and usage method, the requirement for moisture resistance could not be met.

WO2016/047232

The present invention has been made in view of the above problems, and by controlling the amounts of acetonitrile and H ₂ O adsorbed on a porous coordination polymer, the present invention provides good gas detection sensitivity and moisture resistance. The purpose of the present invention is to provide a porous coordination polymer with excellent properties, a gas sensing material, and a gas sensing sheet.

The present inventors have conducted extensive studies, and found that the acetonitrile adsorption amount is in the range of 1.5 wt% or more and 9.5 wt% or less, and the H ₂ O adsorption amount is 1.5 wt% or more, which is represented by the general formula (1). The inventors have discovered that the above object can be achieved by using a porous coordination polymer with a low spin state characterized by a spin content of 7.0 wt% or less, leading to the present invention.
Fe _x (pyrazine) [Ni _1-y M _y (CN) ₄ ] ... (1)
(0.93≦x≦1.1, M=at least one selected from Pd and Pt, 0≦y<0.15)

That is, according to the present invention, the following are provided.
[1] It is represented by the general formula (1), and is characterized by having an acetonitrile adsorption amount of 1.5 wt% or more and 9.5 wt% or less, and a H ₂ O adsorption amount of 1.5 wt% or more and 7.0 wt% or less A porous coordination polymer with a low spin state.
Fe _x (pyrazine) [Ni _1-y M _y (CN) ₄ ] ... (1)
(0.93≦x≦1.1, M=at least one selected from Pd and Pt, 0≦y<0.15)
[2] The porous material according to [1], wherein the mass ratio (A/B) of the acetonitrile adsorption amount (A) and the H ₂ O adsorption amount (B) is 0.33 or more and 6.00 or less. coordination polymer.
[3] A gas sensing material using the porous coordination polymer described in [1] or [2].
[4] A gas sensing sheet in which the porous coordination polymer according to [1] or [2] is supported on a support.

According to the present invention, it is possible to provide a porous coordination polymer, a gas sensing material, and a gas sensing sheet that have good gas sensing sensitivity and excellent moisture resistance.

FIG. 1 is a schematic diagram showing the basic chemical structure of a porous coordination polymer according to the present invention. Infrared absorption spectra of porous coordination polymers of Example 2, Example 5, and Comparative Example 2. FIG. 1 is a schematic diagram showing a gas detection sheet according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments.

The porous coordination polymer of this embodiment is represented by formula (1),
Fe _x (pyrazine) [Ni _1-y M _y (CN) ₄ ] ... (1)
(0.93≦x≦1.1, M=at least one selected from Pd and Pt, 0≦y<0.15)
It is in a low spin state, and the acetonitrile adsorption amount is 1.5 wt% or more and 9.5 wt% or less, and the H ₂ O adsorption amount is 1.5 wt% or more and 7.0 wt% or less.

As shown in FIG. 1, the porous coordination polymer 1 of the present invention has a jungle gym-shaped skeleton in which iron ions 2, tetracyanonickelate ions 3, and pyrazine 4 are regularly coordinated in a self-assembled manner. It has an expanded structure and can adsorb various molecules into the internal space. Further, a portion of nickel may be replaced with at least one of palladium and platinum.

Porous coordination polymer 1 has spin crossover, in which the electron configuration of iron ions changes between two states called a high spin state and a low spin state due to external stimuli such as heat, pressure, and molecular adsorption. A phenomenon called. The spin change is generally said to take several tens of nanoseconds, and is characterized by an extremely fast response speed.

A high spin state refers to a state in which electrons are arranged in the five orbits of d electrons of iron ions in a complex so that the spin angular momentum is maximized according to Hund's law, and a low spin state is a state in which the spin angular momentum is maximum. Refers to the state in which electrons are arranged to be the minimum, and because the electronic states and interstitial distances are different, the color and magnetism of the complex differ between the two states. That is, by utilizing the spin crossover phenomenon caused by the adsorption of molecules onto porous coordination polymers, it becomes possible to use the material as a sensing material that quickly detects specific molecules.

The porous coordination polymer in a high-spin state is orange in color, and when cooled sufficiently with liquid nitrogen, it changes to a reddish-purple color in a low-spin state. Furthermore, when exposed to a specific organic compound gas such as acetonitrile or acrylonitrile, the gas is adsorbed inside the crystal, resulting in a low spin state. When a porous coordination polymer, which is reddish-purple in a low spin state, is exposed to a gas of an organic compound that induces a high spin state, the gas is taken into the jungle gym-shaped skeleton, and the orange color of the high spin state is caused by a spin crossover phenomenon. becomes. Examples of the gases of these organic compounds include organic combustible gases and vapors of volatile organic solvents. That is, the porous coordination polymer in a low spin state is a gas in an electrolyte for lithium ion secondary batteries such as dimethyl carbonate (hereinafter referred to as DMC), diethyl carbonate (hereinafter referred to as DEC), and ethyl methyl carbonate (hereinafter referred to as EMC). In an atmosphere where gases such as ethylene and propylene generated by decomposition of the electrolytic solution are present, these gases are adsorbed and the color turns orange with a high spin state. As mentioned above, by visually checking the color tone, checking the weight change of the gas adsorbed by the porous coordination polymer, and analyzing the gas adsorbed inside the porous coordination polymer, etc. , can be used as a gas detection material.

The composition of the porous coordination polymer of this embodiment can be confirmed by using ICP emission spectrometry, carbon-sulfur analysis, oxygen-nitrogen-hydrogen analysis, and the like.

The spin state of the porous coordination polymer of this embodiment can be confirmed by observing the response of magnetization to a magnetic field using a superconducting quantum interference magnetometer (SQUID) or a vibrating sample magnetometer (VSM). I can do it.

The gas species adsorbed on the porous coordination polymer of this embodiment can be identified by checking the mass number of the generated gas using a gas chromatograph mass spectrometer equipped with a double-shot pyrolyzer. I can do it.

Regarding the amount of gas adsorbed on the porous coordination polymer of this embodiment, thermogravimetric analysis was used to weigh 10 mg of the sample in an aluminum pan, use 10 mg of alumina powder as a reference, and measure the nitrogen gas flow. Determine the amount of gas adsorption per weight of the sample by checking the amount of weight loss in a specific gas generation temperature range from the amount of weight loss up to 220 degrees Celsius under the conditions of medium temperature increase rate of 10 degrees Celsius/min. be able to.

The porous coordination polymer of this embodiment being in a low spin state means that 55% or more of the porous coordination polymer is in a low spin state in an environment of a temperature of 25°C and a humidity of 40%. do. Further, a part of a single particle may be in a high spin state. To determine the proportion of low spin states, Fourier Transform Infrared Spectroscopy (FT-IR) was used to determine the proportion of low spin states at wave numbers 815 to 830 cm ^-1 in measurements under the following measurement conditions. It is determined by the ratio of the intensity of the peak caused by the high spin state at wave numbers 794 to 814 cm ^-1 . Figure 2 shows the infrared absorption spectrum of the porous coordination polymer.
<Measurement conditions>
・Device: Nicolet i S10 (manufactured by Thermo Scientific)
・Detector: DTGS KBr
・Purge: Nitrogen gas ・Resolution: 1cm ^-1
・Number of integration: 16 times ・Measurement method: Attenuated total reflection (ATR) method ・Measurement wavelength: 4,000 to 600 cm ^-1
・ATR crystal: Diamond

The porous coordination polymer of this embodiment has an acetonitrile adsorption amount of 1.5 wt% or more and 9.5 wt% or less, and a H ₂ O adsorption amount of 1.5 wt% or more and 7.0 wt% or less. When the acetonitrile adsorption amount is in the range of 1.5 _wt % or more and 9.5 wt% or less, there is a tendency for the low spin state to become stable. Within this range, there is a tendency for it to be stabilized against atmospheric moisture. Therefore, it is presumed that a low spin state is maintained even in a high humidity environment, and moisture resistance is improved. When the amount of H ₂ O adsorption is less than 1.5 wt%, moisture resistance tends to be insufficient, and when it is more than 7.0 wt%, it is difficult for the porous coordination polymer to maintain a low spin state. Therefore, there is a tendency for gas detection sensitivity to decrease. A more preferable amount of acetonitrile adsorption is 2.0 wt% or more and 8.0 wt% or less. Furthermore, the adsorption amount of H ₂ O is more preferably 2.0 wt% or more and 6.0 wt% or less.

There are no particular restrictions on the method of controlling the amount of acetonitrile adsorbed, but the porous coordination polymer may be left standing in a container filled with acetonitrile vapor, dried under reduced pressure, or placed in an atmosphere of air, nitrogen, argon, or a mixture thereof. There are methods such as heating. There are no particular restrictions on the method of controlling the amount of H ₂ O adsorption, but the porous coordination polymer may be allowed to stand still in a container set at an appropriate temperature and humidity, dried under reduced pressure, or exposed to air, nitrogen, argon, etc. There are methods such as heating in an atmosphere of mixed gas or the like.

Since the mass ratio (A/B) of the acetonitrile adsorption amount (A) and H ₂ O adsorption amount (B) of the porous coordination polymer of this embodiment is 0.33 or more and 6.00 or less, gas detection is possible. It has good sensitivity and better moisture resistance. When A/B is 0.33 or more and 6.00 or less, the results of generated gas analysis and thermal analysis show that the desorption of acetonitrile at low temperatures is suppressed, and acetonitrile becomes a more stable vacancy within the porous coordination polymer. It is presumed that it moves to the position of the hole. Further, it is presumed that the moisture resistance is improved by adsorbing some H ₂ O near the surface of the porous coordination polymer particles.

The method for producing a porous coordination polymer according to the present embodiment includes first adding a divalent iron salt, an antioxidant, a tetracyanonickelate, and optionally a tetracyanopalladate and/or An intermediate is obtained by reacting with tetracyanoplatinate in a suitable solvent. Second, the intermediate is dispersed in a suitable solvent, and pyrazine is added to this dispersion to form a precipitate, and the precipitate is filtered and dried to obtain a porous coordination polymer.

As the divalent iron salt, ferric sulfate heptahydrate, ammonium iron sulfate hexahydrate, etc. can be used. As the antioxidant, L-ascorbic acid and the like can be used. As the tetracyanonickelate, potassium tetracyanonickelate hydrate, etc. can be used. As the tetracyanopalladate, potassium tetracyanopalladate hydrate, etc. can be used. As the tetracyanoplatinate, potassium tetracyanoplatinate hydrate and the like can be used.

As the solvent, methanol, ethanol, propanol, acetonitrile, water, or a mixed solvent thereof can be used.

By using the porous coordination polymer of this embodiment as a gas detection material, it is possible to detect changes in color tone and weight due to gas adsorption even for low-concentration target gases, thereby detecting the effects of temperature and humidity environments. It becomes possible to detect the target gas with high sensitivity without being affected greatly by the

FIG. 3 is a schematic diagram of the gas detection sheet according to this embodiment. In FIG. 3, the gas detection sheet 5 is composed of a porous coordination polymer 6 and a support 7. The porous coordination polymer, which is reddish-purple in a low spin state, adsorbs a gas such as DEC and changes its color from reddish-purple to orange. As described above, if the gas detection sheet 5 of this embodiment is used in the presence of the gas to be detected, the presence of the gas can be easily detected by visually confirming the change in color tone.

In the gas detection sheet of this embodiment, two or more regions having different amounts of porous coordination polymer supported per area may be formed on the support. Two or more regions having different amounts of porous coordination polymer supported per area may be formed on the same surface of the support, or on the front and back surfaces of the support. By forming two or more regions with different amounts of porous coordination polymer supported per area, when gas is detected under the same conditions, the color tone of the region with the smaller amount supported changes first. , visibility is improved by comparing the color with that of a region with a large amount of loading that has not changed. Furthermore, the support may have a region where no porous coordination polymer is supported.

The support 7 is not particularly limited, and for example, a silicon substrate, a metal substrate, a plastic substrate, a cellulose-based cardboard such as a filter paper, a paper filter, etc. can be used. In addition, the color of the support is a color that is complementary to the color after the change due to the porous coordination polymer adsorbing the sensing gas, or when it is white, gray, or black, the color of the porous coordination polymer is This is more preferable because the visibility of color change is improved. Furthermore, the film thickness of the support is not particularly limited, but is preferably 50 to 1000 μm from the viewpoint of ease of handling during production and use of the gas detector.

The method for supporting the porous coordination polymer on the support is not particularly limited, and examples include filtration, spray coating, brush coating, and dip coating. In addition, regarding the amount of the porous coordination polymer supported on the gas detection sheet of this embodiment, the porous coordination polymer was It is calculated from the average amount of Fe element supported per area obtained by measuring 10 locations in the area. The device used was ZSX100e manufactured by Rigaku Co., Ltd. The measurement spot diameter was measured with a 3 mmΦ (5 mmΦ SUS mask holder), and the support was removed using the differential intensity based on the blank measurement value of the support to determine the amount of Fe element supported per area. Calculate. The supported amount of the porous coordination polymer can be determined from the obtained supported amount of Fe and the content ratio of Fe in the porous coordination polymer composition formula determined by compositional analysis. Furthermore, regarding the amount of gas adsorbed per weight of the porous coordination polymer supported on the gas detection sheet, the amount of gas adsorption per weight of the porous coordination polymer supported on the gas detection sheet was compared to that of a blank gas detection sheet in which no porous coordination polymer was supported on the support prepared in the same manner. On the other hand, it can be determined by determining the type and amount of gas contained using the above-mentioned generated gas analysis and thermogravimetric analysis, and subtracting it.

By using the gas detection sheet of this embodiment, it is possible to easily identify the approximate gas concentration and gas generation location by checking the time it takes for the color to change and the location where the color has changed.

The present invention will be described below based on more detailed examples, but the present invention is not limited to these examples.

<Example 1>
(Production of porous coordination polymer)
0.48 g of ammonium iron (II) sulfate hexahydrate, 0.2 g of L-ascorbic acid, and 0.3 g of potassium tetracyanonickel (II) monohydrate were added to 240 mL of a mixed solvent of distilled water and ethanol. The mixture was stirred in an Erlenmeyer flask and precipitated intermediate particles were collected. 0.2 g of the obtained intermediate particles were dispersed in acetonitrile, and 0.14 g of pyrazine was added over 20 minutes while stirring. After stopping the stirring, the precipitate was suction filtered and dried under reduced pressure to obtain a reddish-purple powder on the filter paper. The obtained powder was kept in a constant temperature bath set at a temperature of 22°C and a humidity of 45% for 30 hours, and then left for 1 hour in an environment of a temperature of 25°C and a humidity of 40% to form a porous coordination polymer. was manufactured.

(Evaluation of spin state of porous coordination polymer)
The spin state of the obtained porous coordination polymer was evaluated by the method described above. The percentage of the low spin state was determined from the intensity of the peak due to the low spin state at wave numbers 815 to 830 cm ^-1 and the intensity of the peak due to the high spin state at wave numbers 794 to 814 cm ^-1 , and it was found to be 68%. .

(Measurement of adsorbed gas and adsorption amount of porous coordination polymer)
When the obtained porous coordination polymer was checked for gas components generated up to 220° C. using a gas chromatograph mass spectrometer equipped with a double shot pyrolyzer, only acetonitrile and water were detected. When the amount of gas adsorption was determined by the method described above using thermogravimetric analysis, the amount of acetonitrile adsorption (A) was 2.0%, the amount of H ₂ O adsorption (B) was 6.0%, and the mass ratio A /B=0.33.

(Preparation of gas detection sheet)
A dispersion solution in which 10 mg of the obtained porous coordination polymer was dispersed in 35 ml of acetonitrile was placed in a SUS vat, a roll paper with a thickness of 0.5 mm was immersed therein, and the SUS vat was vibrated. Afterwards, it was allowed to stand for 1 minute. Thereafter, the roll paper was slowly taken out from the dispersion solution, air-dried for 5 minutes, kept in a constant temperature bath set at 22°C and 45% humidity for 30 hours, and then placed in an environment of 25°C and 40% humidity for 1 hour. After leaving it for a while, the gas detection sheet was completed.

(Diethyl carbonate gas detection test)
The obtained porous coordination polymer and gas detection sheet were placed in a 5-liter Tedlar bag, and the bag was filled with nitrogen containing DEC gas to a concentration of 20 ppm. After 20 minutes, the porous coordination polymer It was confirmed by comparison with the color sample that the polymer and gas detection sheet had changed to orange. On the other hand, when only nitrogen was introduced, no change in color tone could be observed. This confirmed that DEC gas can be detected by evaluating the change in color of the porous coordination polymer or gas detection sheet.

(Detection of other gases)
Instead of diethyl carbonate, use ethylene, propylene, toluene, xylene, acetone, ethyl acetate, tetrahydrofuran, methanol, ethanol, n-propanol, isopropanol, ammonia, dimethylamine, trimethylamine, triethylamine, acetic acid, formaldehyde, acetaldehyde, diethyl ether, propion. When ethyl acid, propyl propionate, dioxane, isobutane, propane, tetrafluoroethane, difluoromethane, pentafluoroethane, DMC and EMC were used, the color tone change of the porous coordination polymer and gas detection sheet was similarly confirmed. It was confirmed by comparison with the color sample that the porous coordination polymer and gas detection sheet had changed to orange.

(Moisture resistance test)
The obtained porous coordination polymer and gas detection sheet were placed in a constant temperature bath set at a temperature of 25°C and a humidity of 50%, and after 50 hours, the above-mentioned diethyl carbonate gas detection test was performed. Afterwards, it was confirmed by comparison with the color sample that the porous coordination polymer and gas detection sheet had turned orange.
<Example 2>

The powder after drying under reduced pressure in the manufacturing process of a porous coordination polymer, and the roll paper taken out from the dispersion solution in the manufacturing process of a gas detection sheet and air-dried for 5 minutes, in a constant temperature bath set at a temperature of 23 ° C. and a humidity of 47%. A porous coordination polymer and a gas sensing sheet were produced in the same manner as in Example 1, except that the mixture was held for 60 hours. Table 1 shows the acetonitrile adsorption amount, H ₂ O adsorption amount, A/B value, DEC gas detection test results, and moisture resistance test results obtained in the same manner as in Example 1.
<Example 3>

The powder after drying under reduced pressure in the manufacturing process of porous coordination polymers, and the roll paper taken out from the dispersion solution in the manufacturing process of gas detection sheets and air-dried for 5 minutes, in a constant temperature bath set at a temperature of 23 ° C. and a humidity of 45%. A porous coordination polymer and a gas sensing sheet were produced in the same manner as in Example 1, except that the mixture was held for 30 hours. Table 1 shows the acetonitrile adsorption amount, H ₂ O adsorption amount, A/B value, DEC gas detection test results, and moisture resistance test results obtained in the same manner as in Example 1.
<Example 4>

Powder after drying under reduced pressure in the manufacturing process of porous coordination polymers, and rolled paper taken out from the dispersion solution in the manufacturing process of gas detection sheets and air-dried for 5 minutes in a constant temperature bath set at a temperature of 22°C and a humidity of 43%. A porous coordination polymer and a gas sensing sheet were produced in the same manner as in Example 1, except that the mixture was held for 15 hours. Table 1 shows the acetonitrile adsorption amount, H ₂ O adsorption amount, A/B value, DEC gas detection test results, and moisture resistance test results obtained in the same manner as in Example 1.
<Example 5>

Powder after drying under reduced pressure in the manufacturing process of porous coordination polymers, and rolled paper taken out from the dispersion solution in the manufacturing process of gas detection sheets and air-dried for 5 minutes in a constant temperature bath set at a temperature of 22°C and a humidity of 43%. A porous coordination polymer and a gas detection sheet were produced in the same manner as in Example 1, except that the mixture was held for 8 hours. Table 1 shows the acetonitrile adsorption amount, H ₂ O adsorption amount, A/B value, DEC gas detection test results, and moisture resistance test results obtained in the same manner as in Example 1.
<Example 6>

Powder after drying under reduced pressure in the manufacturing process of porous coordination polymers, and rolled paper taken out from the dispersion solution in the manufacturing process of gas detection sheets and air-dried for 5 minutes in a constant temperature bath set at a temperature of 22°C and a humidity of 43%. A porous coordination polymer and a gas sensing sheet were produced in the same manner as in Example 1, except that the mixture was held for 3 hours. Table 1 shows the acetonitrile adsorption amount, H ₂ O adsorption amount, A/B value, DEC gas detection test results, and moisture resistance test results obtained in the same manner as in Example 1.
<Example 7>

The powder after drying under reduced pressure in the manufacturing process of porous coordination polymers, and the roll paper taken out from the dispersion solution in the manufacturing process of gas detection sheets and air-dried for 5 minutes, in a constant temperature bath set at a temperature of 22 ° C. and a humidity of 40%. A porous coordination polymer and a gas detection sheet were produced in the same manner as in Example 1, except that the mixture was held for 1 hour. Table 1 shows the acetonitrile adsorption amount, H ₂ O adsorption amount, A/B value, DEC gas detection test results, and moisture resistance test results obtained in the same manner as in Example 1.
<Example 8>

The powder after drying under reduced pressure in the manufacturing process of a porous coordination polymer, and the roll paper taken out from the dispersion solution in the manufacturing process of a gas detection sheet and air-dried for 5 minutes, in a constant temperature bath set at a temperature of 21°C and a humidity of 42%. A porous coordination polymer and a gas sensing sheet were produced in the same manner as in Example 1, except that the mixture was held for 15 hours. Table 1 shows the acetonitrile adsorption amount, H ₂ O adsorption amount, A/B value, DEC gas detection test results, and moisture resistance test results obtained in the same manner as in Example 1.
<Comparative example 1>

Powder after drying under reduced pressure in the manufacturing process of porous coordination polymers, and rolled paper taken out from the dispersion solution in the manufacturing process of gas detection sheets and air-dried for 5 minutes in a constant temperature bath set at a temperature of 30°C and humidity of 60%. A porous coordination polymer and a gas detection sheet were produced in the same manner as in Example 1, except that the mixture was held for 100 hours. Table 1 shows the acetonitrile adsorption amount, H ₂ O adsorption amount, A/B value, DEC gas detection test results, and moisture resistance test results obtained in the same manner as in Example 1.
<Comparative example 2>

Powder after drying under reduced pressure in the manufacturing process of porous coordination polymers, and roll paper taken out from the dispersion solution in the manufacturing process of gas detection sheets and air-dried for 5 minutes in a constant temperature bath set at a temperature of 30 ° C. and a humidity of 55%. A porous coordination polymer and a gas sensing sheet were produced in the same manner as in Example 1, except that the mixture was held for 200 hours. Table 1 shows the acetonitrile adsorption amount, H ₂ O adsorption amount, A/B value, DEC gas detection test results, and moisture resistance test results obtained in the same manner as in Example 1.
<Comparative example 3>

The powder after drying under reduced pressure in the manufacturing process of porous coordination polymers and the roll paper taken out from the dispersion solution in the manufacturing process of gas sensing sheets and air-dried for 5 minutes were dried in an environment of 25°C and 40% humidity for 1 hour. A porous coordination polymer and a gas detection sheet were produced in the same manner as in Example 1, except that the conditions were maintained. Table 1 shows the acetonitrile adsorption amount, H ₂ O adsorption amount, A/B value, DEC gas detection test results, and moisture resistance test results obtained in the same manner as in Example 1.

(Evaluation of spin state of porous coordination polymer)
For the porous coordination polymers of Examples 2 to 8 and Comparative Examples 1 to 3, the proportion of low spin states was determined in the same manner as in Example 1. The proportion of the low spin state of the porous coordination polymers of Examples 2 to 8 and Comparative Example 3 was 55% or more. The proportions of the low spin state in the porous coordination polymers of Comparative Examples 1 and 2 were 3% and 8%, respectively.

(Diethyl carbonate gas detection test)
A detection test using DEC gas was conducted in the same manner as in Example 1 for the porous coordination polymers and gas detection sheets of Examples 2 to 8 and Comparative Examples 1 to 3. It was confirmed by comparison with the color sample that the porous coordination polymer and gas detection sheet of Example 2 changed to orange after 28 minutes. It was confirmed by comparison with the color sample that the porous coordination polymers and gas detection sheets of Examples 3 to 8 and Comparative Example 3 changed to orange after 20 to 23 minutes. The porous coordination polymers and gas detection sheets of Comparative Examples 1 and 2 had already exhibited a color close to the orange color sample before the test, and no change in color was visible even after 60 minutes had passed. .

(Weather resistance test)
A moisture resistance test was conducted in the same manner as in Example 1 for the porous coordination polymers and gas detection sheets of Examples 2 to 8 and Comparative Examples 1 to 3. Regarding the porous coordination polymer and gas detection sheet of Example 2, as a result of a DEC gas detection test, it was confirmed by comparison with a color sample that the color changed to orange after 29 minutes. As a result of a DEC gas detection test for the porous coordination polymers and gas detection sheets of Examples 3 to 8, it was confirmed that the color changed to orange after 20 to 25 minutes by comparison with a color sample. The porous coordination polymers and gas detection sheets of Comparative Examples 1 to 3 exhibited a color close to the orange color sample after 50 hours in a constant temperature bath set at a temperature of 25°C and a humidity of 50%. As a result of the detection test, no color change could be visually recognized even after 60 minutes.

<Examples 9 to 18 and Comparative Examples 4 to 6>
Ammonium iron(II) sulfate hexahydrate, potassium tetracyanonickel(II) monohydrate, potassium tetracyanopalladate hydrate, and potassium tetracyanoplatinate water so as to have the compositions listed in Table 2. Table 2 shows the acetonitrile adsorption amount, H ₂ O adsorption amount, A/B value, DEC gas detection test results, and moisture resistance test results obtained in the same manner as in Example 1, except that the hydrate was weighed.

(Evaluation of spin state of porous coordination polymer)
For the porous coordination polymers of Examples 9 to 18 and Comparative Examples 4 to 6, the proportion of low spin states was determined in the same manner as in Example 1. The proportion of the low spin state of the porous coordination polymers of Examples 9 to 18 was 55% or more. The proportions of the low spin state in the porous coordination polymers of Comparative Examples 4 to 6 were 12%, 6%, and 5%, respectively.

(Diethyl carbonate gas detection test)
A detection test using diethyl carbonate gas was conducted in the same manner as in Example 1 for the porous coordination polymers and gas detection sheets of Examples 9 to 18 and Comparative Examples 4 to 6. It was confirmed by comparison with the color sample that the porous coordination polymers and gas detection sheets of Examples 9 and 12 to 17 turned orange after 21 to 24 minutes. As a result of a DEC gas detection test for the porous coordination polymers and gas detection sheets of Examples 10, 11, and 18, it was confirmed by comparison with the color sample that the color changed to orange after 28 to 30 minutes. The porous coordination polymers and gas detection sheets of Comparative Examples 4 to 6 had already exhibited a color close to the orange color sample before the test, and no change in color was visible even after 60 minutes had passed. .

(Weather resistance test)
A moisture resistance test was conducted in the same manner as in Example 1 for the porous coordination polymers and gas detection sheets of Examples 9 to 18 and Comparative Examples 4 to 6. As a result of a DEC gas detection test for the porous coordination polymers and gas detection sheets of Examples 9 and 12 to 16, it was confirmed by comparison with the color sample that the color changed to orange after 22 to 25 minutes. As a result of the DEC gas detection test for the porous coordination polymers and gas detection sheets of Examples 10, 11, 17, and 18, it was confirmed by comparison with the color sample that the color changed to orange after 29 to 32 minutes. The porous coordination polymers and gas detection sheets of Comparative Examples 4 to 6 exhibited a color close to the orange color sample after 50 hours in a constant temperature bath set at a temperature of 25°C and a humidity of 50%. As a result of the detection test, no color change could be visually recognized even after 60 minutes.

From the above results, the porous coordination polymer of the example has excellent gas detection performance and can be used as a gas detection material having excellent moisture resistance. Further, the gas sensing material sheet produced using the porous coordination polymer of the example has excellent moisture resistance and can detect gases with high sensitivity.

1...Porous coordination polymer 2...Iron ion 3...Tetracyanonickelate ion 4...Pyrazine 5...Gas detection sheet 6...Porous coordination polymer 7...Support

Claims (4)

It is a porous coordination polymer represented by the general formula (1) in which acetonitrile and H ₂ O are adsorbed, and the amount of acetonitrile adsorbed is 1.5 to 9.5 wt%, and furthermore, the amount of H ₂ O adsorbed is 1. A porous coordination polymer in a low spin state, characterized in that the content is .5 to 7.0 wt%.
Fe _x (pyrazine) [Ni _1-y M _y (CN) ₄ ] ... (1)
(0.93≦x≦1.1, M=at least one selected from Pd and Pt, 0≦y<0.15) The porous coordination height according to claim 1, wherein the mass ratio (A/B) of the acetonitrile adsorption amount (A) and the H ₂ O adsorption amount (B) is 0.33 or more and 6.00 or less. molecule. A gas sensing material using the porous coordination polymer according to claim 1 or 2. A gas sensing sheet comprising the porous coordination polymer according to claim 1 or 2 supported on a support.

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