Method for supplying and recovering crown ether and ion-conducting crystal

Abstract

To quantitatively release crown ether from an ion-conducting crystal into a solution and recover it from the solution into the ion-conducting crystal.SOLUTION: A method of supplying and recovering crown ether includes: a crown ether supply step of releasing one or more arbitrary crown ethers among three crown ethers forming an ion channel from the inside of an ion conductive crystal into an aqueous solution to obtain an ion conductive crystal in a second form by immersing an ion-conductive crystal in a first form in which three crown ethers form the ion channel and lithium ions are included in the ion channel in an aqueous solution in which a metal ion other than lithium ion or an organic cation is dissolved; and a crown ether recovery step of incorporating one or more crown ethers from an aqueous solution into the ion conductive crystal in the second form by immersing the ion conductive crystal in the second form in an aqueous solution in which lithium ions and crown ethers are dissolved.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for supplying and recovering crown ethers and ion-conducting crystals. [Background technology]

[0002] Previously, the absorption of molecules has been observed in zeolites and metal-organic frameworks (MOFs) with molecular-level pores, and the release of molecules is known to occur through the desorption of water of crystallization.

[0003] Various ion exchange methods are known in which ions in an ion exchanger are released into an electrolyte solution and ions in the electrolyte solution are taken in. For example, Patent Document 1 discloses an ion exchange method using an ion-conductive crystal in which ion channels are formed by crown ether as an ion exchanger. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6469515 Summary of the Invention [Problem to be solved by the invention]

[0005] Patent Document 1 describes the exchange of lithium ions in the ion channels with potassium ions or sodium ions while the ion-conducting crystal maintains its crystallinity, but does not disclose the absorption or release of molecules. It is extremely difficult to construct a system that can quantitatively and repeatedly perform the absorption and release of molecules, which is a chemically reverse reaction.

[0006] The present inventors focused on the bistability of such ion-conducting crystals and investigated the construction of a system for releasing and absorbing molecules. As a result, they discovered for the first time that it is possible to release crown ethers, which are large molecules, into an aqueous solution and recover them from the aqueous solution.

[0007] The present invention has been made in view of the above points, and has as its object to enable quantitative supply and recovery of crown ethers.

[0008] This allows, for example, the solubility of poorly soluble substances in aqueous solutions to be increased by crown ethers, and also allows the recovery of unnecessary crown ethers from aqueous solutions, which may have a secondary effect on drug delivery systems. [Means for solving the problem]

[0009] In order to achieve the above object, the method for supplying and recovering a crown ether of the present disclosure comprises: a crown ether supplying step of immersing an ion-conductive crystal of a first form, which is composed of a unit containing three crown ethers and two dithiolate metal complexes, the three crown ethers being one-dimensionally stacked to form an ion channel and in which lithium ions are encapsulated in the ion channel, in an aqueous solution in which metal ions other than lithium ions or organic cations are dissolved, thereby exchanging the lithium ions in the ion-conductive crystal of the first form with the metal ions or the organic cations and releasing any number of one or more of the three crown ethers forming the ion channel from within the ion-conductive crystal into the aqueous solution, thereby obtaining an ion-conductive crystal of a second form; and a crown ether recovery step of immersing the ion-conductive crystal of the second form in an aqueous solution in which lithium ions and crown ethers are dissolved, thereby exchanging the metal ions or the organic cations in the ion-conductive crystal of the second form for the lithium ions, and incorporating one or more crown ethers from the aqueous solution into the ion-conductive crystal of the second form, thereby obtaining the ion-conductive crystal of the first form. [Effects of the Invention]

[0010] According to the present invention, crown ether, which is a large molecule, can be quantitatively released from within the crystal into an aqueous solution and then recovered from the aqueous solution back into the crystal. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing the bonding state of an ion conductive crystal according to an embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a diagram showing the results of structural analysis of the ion-conducting crystal of the first form represented by formula (2). [Figure 3] FIG. 2 is a diagram showing the results of structural analysis of the ion-conducting crystal of the second form represented by formula (5). [Figure 4] FIG. 2 is a diagram showing the results of structural analysis of the ion-conducting crystal of the second form represented by formula (6). [Figure 5] FIG. 2 is a diagram showing the results of structural analysis of the ion-conducting crystal of the second form represented by formula (7). DETAILED DESCRIPTION OF THE INVENTION

[0012] The method disclosed herein is a method for supplying and recovering a crown ether, comprising: a crown ether supplying step of immersing an ion-conductive crystal of a first form, the crystal being composed of a unit containing three crown ethers and two dithiolate metal complexes, the three crown ethers being stacked one-dimensionally to form an ion channel and lithium ions being encapsulated in the ion channel, in a solution containing a metal ion other than lithium ion (hereinafter simply referred to as "metal ion") or an organic cation, thereby exchanging the lithium ions in the ion-conductive crystal of the first form with the metal ion or the organic cation, and releasing any number of crown ethers among the three crown ethers forming the ion channel from the ion-conductive crystal into the aqueous solution, thereby obtaining an ion-conductive crystal of a second form; and a crown ether recovery step of immersing the ion-conductive crystal of the second form in an aqueous solution containing lithium ions and crown ethers, thereby exchanging the metal ions or the organic cations in the ion-conductive crystal of the second form with the lithium ions, and incorporating one or more crown ethers from the aqueous solution into the ion-conductive crystal of the second form, thereby obtaining an ion-conductive crystal of the first form.

[0013] This method allows the quantitative supply of large molecules, such as crown ethers, to a solution, and also allows the recovery of the crown ethers in the solution into crystals.

[0014] The ion-conductive crystal is composed of a unit containing a crown ether (18-crown-6-ether) containing a lithium ion and a dithiolate nickel complex (Ni(dmit)2). Specifically, the ion-conductive crystal used in the present invention is represented by the following formula (1):

[0015] [ka]

[0016] In formula (1), 18-crown-6 represents 18-crown-6-ether, and dmit represents 1,3-dithiol-2-thione-4,5-dithiolate. The same applies to the following formulae.

[0017] The structure of the ion-conducting crystal represented by formula (1) is shown in Figure 1. As shown in Figure 1, the ion-conducting crystal 1 is composed of two lithium ions 2, three crown ethers 3, two dithiolate nickel complexes 4, and four water molecules 5, and is represented by the following chemical formula:

[0018] [ka]

[0019] As shown in FIG. 1, three crown ethers 3 are stacked one-dimensionally, and the vacancies are arranged in a continuous manner, thereby forming an ion channel 6 within the crystal. Lithium ions 2 can move within the ion channel 6, passing through the continuous vacancies of the three crown ethers 3. Therefore, the crystal represented by formula (2) has ion conductivity. The ion-conductive crystal shown in FIG. 1 and formula (2) is referred to as a first form of ion-conductive crystal in this embodiment.

[0020] Next, the outline of the method for producing the ion-conductive crystal in this embodiment is shown in the following synthesis scheme.

[0021] [ka]

[0022] <Synthesis scheme of ion-conducting crystals> The crown ether (Li) is a monovalent cation that encapsulates lithium ions. +To obtain an ion-conducting crystal consisting of (18-crown-6-ether) and a monovalent anion, dithiolate nickel complex, first prepare a solution by dissolving 18-crown-6 of formula (3) and lithium perchlorate (LiClO4) in acetonitrile.

[0023] Alternatively, TBA·Ni(dmit)2 (tetrabutylammonium bis(1,3-dithiol-2-thione-4,5-dithiolate)nickelate(III)) is synthesized and dissolved in acetonitrile to prepare a solution containing a dithiolate nickel complex. TBA·Ni(dmit)2 can be synthesized by a known method (see, for example, Steimecke, G. Sieler, H.-J. Kirmse, R. Hoyer, E. 1,3-Dithiol-2-Thion-4,5-Dithiolate Schwefelkohlenstoff und Alkalimetall. Phosphorus Sulfur Relat. Elem. 1979, 7, 49-55).

[0024] Next, an acetonitrile solution (hereinafter referred to as "Solution A") containing lithium perchlorate and crown ether (18-crown-6-ether) is poured into the beaker, and then an acetonitrile solution (hereinafter referred to as "Solution B") containing a dithiolate nickel complex is poured into the beaker, taking care not to mix Solutions A and B too quickly.

[0025] Next, the beaker was left uncovered in a dark place at room temperature for 3 to 4 days, whereby the lithium-crown ether (Li ) encapsulating the lithium ion represented by formula (4) was obtained as shown in formula (1) above. + The (18-crown-6-ether) and the dithiolate nickel complex are electrically attracted to each other, and an ion-conducting crystal represented by formula (2) can be obtained.

[0026] <Supply and recovery of crown ethers> When the ion-conductive crystal of the first form represented by formula (2) is immersed in an aqueous solution in which a metal ion other than lithium or an organic cation is dissolved, the lithium ions in the ion-conductive crystal of the first form are exchanged with the metal ion or organic cation, and one or more of the three crown ethers that form the ion channel are released into the aqueous solution.

[0027] Furthermore, by immersing the second type ion-conductive crystal from which the crown ether has been released in an aqueous solution containing lithium and the crown ether, the crown ether in the aqueous solution is recovered into the ion-conductive crystal, and the first type ion-conductive crystal is obtained again.

[0028] As metal ions or organic cations other than lithium ions, various ion species are considered to be applicable. For example, calcium ions (Ca 2+ ), methylammonium ion (CH3NH3 + ), ethylammonium ion (CH3CH2NH3 + ), ethylenediammonium ion (NH3 + CH2CH2NH3 + ), propylenediammonium ion (NH3 + CH2CH2CH2NH3 + )

[0029] The ion conductive crystal of the above embodiment may be modified as follows.

[0030] In the above embodiment, a dithiolate nickel complex (Ni(dmit)2) was used as the dithiolate metal complex, but the dithiolate metal complex is not limited to this and may be an anion that maintains charge neutrality. For example, a dithiolate palladium complex (Pd(dmit)2), a dithiolate platinum complex (Pt(dmit)2), or a dithiolate gold complex (Au(dmit)2) may be used.

[0031] Furthermore, it is thought that various crown ethers can be used for ion-conducting crystals. Crown ethers are known to encapsulate metal ions and organic cations depending on their ring size, and by changing the type of crown ether, it may be possible to recover industrially useful cations such as rare metals and pharmaceuticals.

[0032] In addition to the 18-crown-6-ether used in this embodiment, it is believed that 12-crown-4-ether, 15-crown-5-ether, 21-crown-7-ether, 24-crown-8-ether, 1-aza-15-crown-5-ether, 1-aza-18-crown-6-ether, 4,13-diaza-18-crown-6-ether, etc. can also be used. [Example]

[0033] The present invention will be described below based on examples. However, the present invention is not limited to these examples, and these examples can be modified or changed based on the spirit of the present invention, and such modifications are not excluded from the scope of the present invention.

[0034] (Synthesis of ion-conducting crystals) 1600 mg (2.27 mmol) of 18-crown-6-ether of formula (3) (manufactured by Tokyo Chemical Industry Co., Ltd., trade name: 18-crown-6-Ether) and 60 mg (2.27 mmol) of lithium perchlorate (anhydrous) (manufactured by Kanto Chemical Co., Ltd., trade name: Lithium perchlorate, anhydrous) were dissolved in 60 ml of acetonitrile (manufactured by Nacalai Tesque, Inc.) to obtain solution A.

[0035] Furthermore, TBA·Ni(dmit)2 was synthesized by a known method, and then 250 mg (0.072 mmol) of this TBA·Ni(dmit) was dissolved in 60 ml of acetonitrile (manufactured by Nacalai Tesque, Inc.) to obtain Solution B containing a dithiolate nickel complex.

[0036] Next, solution A was poured into the beaker as the lower layer, and then solution B was slowly poured into the beaker as the upper layer, taking care not to mix solutions A and B rapidly (so as not to disturb the interface of solution A).

[0037] Next, the beaker into which solutions A and B had been poured was left uncovered at room temperature for one week. After this, black plate-like crystals precipitated at the bottom of the beaker, yielding the first form of ion-conducting crystal represented by formula (2). Figure 2 shows the crystal structure of the first form of ion-conducting crystal obtained by X-ray crystal structure analysis. It was confirmed that an ion channel was formed within the crystal by one-dimensionally stacking three crown ethers, and that two lithium ions were present within the ion channel.

[0038] Next, we will explain the crown ether supplying step in which the obtained ion-conductive crystal of the first type is immersed in a solution containing dissolved calcium ions to release the crown ether from the ion-conductive crystal into the aqueous solution. This step is represented by the following formula:

[0039] [ka]

[0040] (Ca 2+ (Crown ether supply process by The ion-conductive crystal of the first form represented by formula (2) was immersed in a 1 M calcium chloride aqueous solution, left to stand in a thermostatic chamber at 30°C for 24 hours, and then suction filtered. The crystal structure of the obtained ion-conductive crystal, as determined by X-ray crystal structure analysis, is shown in Figure 3.

[0041] From Figure 3, it was confirmed that the obtained ion-conductive crystal was the second form of ion-conductive crystal, which is composed of a unit containing one crown ether and two dithiolate metal complexes, and in which calcium ions are encapsulated within the crown ether, as shown in formula (5). That is, the lithium ions in the first form of ion-conductive crystal were exchanged for calcium ions in the aqueous solution, and two of the three crown ethers that form the ion channels were released from the first form of ion-conductive crystal, supplying the crown ether to the aqueous solution.

[0042] (Na + (Crown ether supply process by The ion-conducting crystal of the first type can exchange lithium ions for sodium ions and crown ethers for other crown ethers with different skeletons. For example, the reaction represented by the following formula is explained below. In the formula, 15-crown-5 represents 15-crown-5-ether.

[0043] [ka]

[0044] The ion-conductive crystal of the first form represented by formula (2) was immersed in a 1 M aqueous solution of 15-crown-5-ether and a sodium chloride solution, and left to stand in a thermostatic chamber at 30°C for 24 hours, after which it was suction filtered. The crystal structure of the obtained ion-conductive crystal, as determined by X-ray crystal structure analysis, is shown in Figure 4.

[0045] From Figure 4, we confirmed that the obtained ion-conductive crystal was the second form of ion-conductive crystal, represented by formula (6), which is composed of units containing three 15-crown-5 ethers and two dithiolate metal complexes, and in which sodium ions are encapsulated within the 15-crown-5 ethers. In other words, the lithium ions in the first form of ion-conductive crystal were exchanged for sodium ions in the aqueous solution, and all three 18-crown-6 ethers forming ion channels were exchanged for 15-crown-5 ethers. The 18-crown-6 ether was released from the first form of ion-conductive crystal and supplied to the aqueous solution.

[0046] Next, a crown ether recovery step will be described in which the obtained ion-conductive crystal of the second form is immersed in a solution in which lithium ions are dissolved, thereby recovering the crown ether from the aqueous solution into the ion-conductive crystal.

[0047] (Crown ether recovery process) The ion-conductive crystal of the second form obtained above was immersed in a 1 M aqueous solution of 18-crown-6-ether and lithium perchlorate, allowed to stand in a thermostatic chamber at 30°C for 24 hours, and then subjected to suction filtration. X-ray crystal structure analysis confirmed that the obtained ion-conductive crystal was the ion-conductive crystal of the first form, in which an ion channel was formed within the crystal by one-dimensional stacking of three crown ethers and two lithium ions were present in the ion channel. In other words, the crown ether in the aqueous solution was recovered in the ion-conductive crystal.

[0048] From the above results, it was confirmed that the reaction of supplying and recovering the crown ether shown in the following formula can be carried out reversibly.

[0049] [ka]

[0050] Next, we will explain the crown ether supplying step in which the ion-conductive crystal of the first embodiment is immersed in a solution containing dissolved methylammonium ions to release the crown ether from the ion-conductive crystal into the aqueous solution. This step is represented by the following formula:

[0051] [ka]

[0052] (CH3NH3 + (Crown ether supply process by First, methylammonium tetrafluoroborate was synthesized by a known method (see, for example, Satyawan Nagane, Satishchandra Ogale, et al., Chem. Commun., 2014, 50, 9741). 100 mL of ethanol and 43 mL (0.50 mol) of methylamine were added to a 500 mL recovery flask. The recovery flask was stirred in an ice bath, and 115 g (0.55 mol) of tetrafluoroboric acid was added dropwise. The mixture was then stirred for 2 hours in the ice bath. The reaction solution was concentrated under reduced pressure using a rotary evaporator to obtain a crude product. The crude product was recrystallized from acetone to obtain methylammonium tetrafluoroborate as a white, transparent powder.

[0053] The synthesized methylammonium tetrafluoroborate was then prepared into a 1 M aqueous solution. The ion-conductive crystal of the first form represented by formula (2) was immersed in the 1 M methylammonium tetrafluoroborate aqueous solution, left to stand in a thermostatic chamber at 30°C for 3 days, and then suction filtered. The crystal structure of the obtained ion-conductive crystal, as determined by X-ray crystal structure analysis, is shown in Figure 5.

[0054] From Figure 5, it was confirmed that the obtained ion-conductive crystal was the second form of ion-conductive crystal represented by formula (7), which is composed of a unit containing two crown ethers and two dithiolate metal complexes, and in which methylammonium ions are encapsulated within the crown ether. That is, the lithium ions in the first form of ion-conductive crystal were exchanged for methylammonium ions in the aqueous solution, and one of the three crown ethers forming the ion channel was released from the first form of ion-conductive crystal into the aqueous solution.

[0055] The ion-conductive crystal of the second form, represented by formula (7), in which methylammonium ions are encapsulated in the crown ether thus obtained can be used in the same manner as the ion-conductive crystal of the second form, represented by formula (5), to obtain the ion-conductive crystal of the first form, represented by formula (2). Specifically, the ion-conductive crystal of the second form, which is composed of units containing two crown ethers and two dithiolate metal complexes, and in which the two crown ethers are one-dimensionally stacked to form an ion channel and methylammonium ions are encapsulated in the ion channel, can be immersed in an aqueous solution containing lithium ions and crown ethers to exchange the methylammonium ions in the ion-conductive crystal of the second form for lithium ions, and one crown ether is incorporated from the aqueous solution into the ion-conductive crystal of the second form. This exchange exchange results in the formation of an ion channel in which three crown ethers are one-dimensionally stacked, and the ion-conductive crystal of the first form, in which lithium ions are encapsulated in the ion channel, can be obtained.

[0056] As described above, the one-dimensional stacking of three crown ethers forms an ion channel within the crystal. When the ion-conductive crystal of the first form, which has two lithium ions in the ion channel, is immersed in an aqueous solution containing calcium ions, two of the three crown ethers forming the ion channel are released. When the ion-conductive crystal of the second form, from which the crown ethers have been released, is immersed in an aqueous solution containing crown ether and lithium ions, the crown ether in the aqueous solution is recovered, and the crystal reverts to the ion-conductive crystal of the first form.

[0057] That is, the ion-conductive crystal of this embodiment can quantitatively supply crown ether to an aqueous solution or recover crown ether from the aqueous solution depending on the ion species contained in the aqueous solution in which it is immersed. [Industrial Applicability]

[0058] An example of the use of the present invention is to have a secondary effect on a drug delivery system. [Explanation of symbols]

[0059] 1. Ion-conducting crystals 2. Lithium-ion 3 Crown ethers 4. Dithiolate Nickel Complex 5 water molecules 6. Ion Channels

Claims

1. a crown ether supplying step of immersing an ion-conductive crystal of a first form, which is composed of a unit containing three crown ethers and two dithiolate metal complexes, the three crown ethers being one-dimensionally stacked to form an ion channel and in which lithium ions are encapsulated in the ion channel, in an aqueous solution in which metal ions other than lithium ions or organic cations are dissolved, thereby exchanging the lithium ions in the ion-conductive crystal of the first form with the metal ions or the organic cations and releasing any number of one or more of the three crown ethers forming the ion channel from within the ion-conductive crystal into the aqueous solution, thereby obtaining an ion-conductive crystal of a second form; and a crown ether recovery step of immersing the ion-conductive crystal of the second form in an aqueous solution in which lithium ions and crown ethers are dissolved, thereby exchanging the metal ions or the organic cations in the ion-conductive crystal of the second form for lithium ions, and incorporating one or more arbitrary number of crown ethers from the aqueous solution into the ion-conductive crystal of the second form, thereby obtaining the ion-conductive crystal of the first form.

2. The method for supplying and recovering a crown ether according to claim 1, wherein the crown ether is 18-crown-6-ether, the first type of ion-conductive crystal is represented by the following formula (1), and the metal ion or the organic cation is at least one selected from the group consisting of calcium ion, methylammonium ion, ethylammonium ion, ethylenediammonium ion, and propylenediammonium ion: 【Chemical 1】 (In the formula, 18-crown-6 represents 18-crown-6-ether, dmit represents 1,3-dithiol-2-thione-4,5-dithiolate, and M represents any one of Ni, Pd, Au, and Pt.)

3. A method for supplying a crown ether, comprising: immersing an ion-conductive crystal of a first form, the ion-conductive crystal being composed of a unit containing three crown ethers and two dithiolate metal complexes, the three crown ethers being stacked one-dimensionally to form an ion channel, and lithium ions being encapsulated in the ion channel, in an aqueous solution having calcium ions dissolved therein, thereby exchanging the lithium ions in the ion-conductive crystal of the first form with the calcium ions and releasing two of the three crown ethers forming the ion channel from within the ion-conductive crystal into the aqueous solution, thereby obtaining an ion-conductive crystal of a second form.

4. A method for recovering a crown ether, comprising: immersing an ion-conductive crystal of a second form, which is composed of a unit containing one crown ether and two dithiolate metal complexes and in which calcium ions are encapsulated in the crown ether, in an aqueous solution in which lithium ions and a crown ether are dissolved, thereby exchanging the calcium ions in the ion-conductive crystal of the second form for lithium ions and incorporating two of the crown ethers from the aqueous solution into the ion-conductive crystal of the second form, whereby three of the crown ethers are one-dimensionally stacked to form an ion channel, thereby obtaining an ion-conductive crystal of a first form in which lithium ions are encapsulated in the ion channel.

5. A method for supplying a crown ether, comprising: immersing an ion-conductive crystal of a first form, the ion-conductive crystal being composed of a unit containing three crown ethers and two dithiolate metal complexes, the three crown ethers being stacked one-dimensionally to form an ion channel, and lithium ions being encapsulated in the ion channel, in an aqueous solution having methylammonium ions dissolved therein, thereby exchanging the lithium ions in the ion-conductive crystal of the first form with the methylammonium ions and releasing one of the three crown ethers forming the ion channel from within the ion-conductive crystal into the aqueous solution, thereby obtaining an ion-conductive crystal of a second form.

6. A method for recovering a crown ether, comprising: immersing an ion-conductive crystal of a second form, the ion-conductive crystal comprising a unit containing two crown ethers and two dithiolate metal complexes, the two crown ethers stacked one-dimensionally to form an ion channel, and a methylammonium ion encapsulated in the ion channel, in an aqueous solution having lithium ions and a crown ether dissolved therein, thereby exchanging the methylammonium ions in the ion-conductive crystal of the second form for lithium ions and incorporating one crown ether from the aqueous solution into the ion-conductive crystal of the second form, thereby obtaining an ion-conductive crystal of a first form, the ion-conductive crystal comprising a unit containing two crown ethers and two dithiolate metal complexes, the two crown ethers stacked one-dimensionally to form an ion channel, and a methylammonium ion encapsulated in the ion channel.

7. A method for supplying a crown ether, comprising: immersing an ion-conductive crystal of a first form, the ion-conductive crystal being composed of units containing three 18-crown-6-ethers and two dithiolate metal complexes, the three 18-crown-6-ethers being one-dimensionally stacked to form an ion channel, with lithium ions being encapsulated in the ion channel, in an aqueous solution having dissolved therein sodium ions and 15-crown-5-ether, thereby exchanging the lithium ions in the ion-conductive crystal of the first form for sodium ions and exchanging the three 18-crown-6-ethers forming the ion channel for three 15-crown-5-ethers, and releasing the 18-crown-6-ethers from within the ion-conductive crystal into the aqueous solution, thereby obtaining an ion-conductive crystal of a second form.

8. An ion-conducting crystal represented by the following formula (2), which is composed of a unit containing one crown ether and two dithiolate metal complexes, and in which calcium ions are encapsulated within the crown ether: 【Chemistry 2】 (In the formula, 18-crown-6 represents 18-crown-6-ether, dmit represents 1,3-dithiol-2-thione-4,5-dithiolate, and M represents any one of Ni, Pd, Au, and Pt.)

9. An ion-conducting crystal represented by the following formula (3), which is composed of a unit containing two crown ethers and two dithiolate metal complexes, and in which a methylammonium ion is encapsulated within the crown ether: 【Chemistry 3】 (In the formula, 18-crown-6 represents 18-crown-6-ether, dmit represents 1,3-dithiol-2-thione-4,5-dithiolate, and M represents any one of Ni, Pd, Au, and Pt.)

10. An ion-conducting crystal represented by the following formula (4), which is composed of units containing three crown ethers and two dithiolate metal complexes, and in which sodium ions are encapsulated within the crown ethers: 【Chemistry 4】 (In the formula, 15-crown-5 represents 15-crown-5-ether, dmit represents 1,3-dithiol-2-thione-4,5-dithiolate, and M represents any one of Ni, Pd, Au, and Pt.)

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