Coordination polymer film and method for producing the same

Abstract

To provide a coordination polymer membrane having rectifying characteristics and a method for preparing a coordination polymer membrane.SOLUTION: There are provided a coordination polymer membrane comprising: a first region having a transition metal atom selected from Fe, Co, Ni, Cu, Pd or Pt as a central metal and containing a constitutional unit selected from two specific constitutional units coordinated with a sulfur atom; and a second region having a transition metal atom different from the first region selected from Fe, Co, Ni, Cu, Pd or Pt as a central metal and containing a constitutional unit selected from two specific constitutional units coordinated with a sulfur atom, and a method for producing the same.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to coordination polymer membranes and methods for making coordination polymer membranes. [Background technology]

[0002] Materials with nanometer-order thicknesses and two-dimensional structures are called nanosheets, and are expected to be applied to electronic device materials. For example, nanosheets formed by coordination polymers have been actively studied. Coordination polymers are known as materials with a structure in which structural units formed by the coordination of multidentate ligands to a central metal are continuously linked together.

[0003] For example, Patent Document 1 below discloses an electrochromic sheet for an electrochromic device. The electrochromic sheet disclosed in Patent Document 1 below is formed from a metal complex polymer, and the metal complex polymer has a hexagonal network molecular structure constructed by repeated linkage of two terpyridine derivatives via one central metal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-136556 Summary of the Invention [Problem to be solved by the invention]

[0005] Coordination polymer films are expected to exhibit various functions depending on the combination of central metals and multidentate ligands. For example, the development of coordination polymer films that exhibit rectifying properties could increase the feasibility of applying coordination polymer films to electronic device materials.

[0006] An object of one embodiment of the present disclosure is to provide a coordination polymer membrane that exhibits rectifying properties. It is an object of another embodiment of the present disclosure to provide a method for fabricating a coordination polymer film that exhibits rectifying properties. It is an object of another embodiment of the present disclosure to provide a coordination polymer film that is useful as a precursor to a coordination polymer film that exhibits rectifying properties. [Means for solving the problem]

[0007] The present disclosure includes the following aspects. <1> A coordination polymer film comprising: a first region containing a constitutional unit represented by the following formula (1) or a constitutional unit represented by the following formula (2); and a second region containing a constitutional unit represented by the following formula (3) or a constitutional unit represented by the following formula (4).

[0008] [ka]

[0009] In formula (1) and formula (2), M 1 represents a transition metal atom.

[0010] [ka]

[0011] In formula (3) and formula (4), M 2 is the above M 1 represents a transition metal atom different from the transition metal atom represented by the formula:

[0012] <2> The above M 1 is Fe, Co, Ni, Cu, Pd or Pt, and 2 The transition metal atom represented by the formula (I) is Fe, Co, Ni, Cu, Pd or Pt. <1> The coordination polymer membrane according to claim 1. <3> The above M 1 is Fe, Ni or Cu, and 2 The transition metal atom represented by the formula (I) is Fe, Ni or Cu. <1> The coordination polymer membrane according to claim 1. <4> The above M 1 is Cu, and the M 2 The transition metal atom represented by the formula (I) is Fe. <1> The coordination polymer membrane according to claim 1. <5> A method for producing a coordination polymer film, comprising: preparing a coordination polymer film containing a constitutional unit represented by the following formula (5); forming a first region in a part of the coordination polymer film by a metal exchange reaction, the first region containing a constitutional unit represented by the following formula (1) or a constitutional unit represented by the following formula (2); and forming a second region in a part of the coordination polymer film by a metal exchange reaction, the second region containing a constitutional unit represented by the following formula (3) or a constitutional unit represented by the following formula (4).

[0013] [ka]

[0014] [ka]

[0015] In formula (1) and formula (2), M 1 represents a transition metal atom.

[0016] [ka]

[0017] In formula (3) and formula (4), M 2 is the above M 1 represents a transition metal atom different from the transition metal atom represented by the formula:

[0018] <6> A coordination polymer film containing a constitutional unit represented by the following formula (5):

[0019] [ka] [Effects of the Invention]

[0020] According to one embodiment of the present disclosure, a coordination polymer film exhibiting rectifying properties is provided. According to another embodiment of the present disclosure, there is provided a method for producing a coordination polymer film that exhibits rectifying properties. According to another embodiment of the present disclosure, there is provided a coordination polymer film useful as a precursor to a coordination polymer film exhibiting rectifying properties. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a graph showing the current-voltage characteristics measured by the combination of probes 1 and 2 in Example 5. [Figure 2] FIG. 2 is a graph showing the current-voltage characteristics measured using the combination of probe 2-1 in Example 5. [Figure 3] FIG. 3 is a graph showing the current-voltage characteristics measured by the combination of probes 1-4 in Example 5. [Figure 4] FIG. 4 is a graph showing the current-voltage characteristics measured by the combination of probes 2 and 3 in Example 5. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present disclosure will be described in detail. The present disclosure is not limited to the following embodiments. The following embodiments may be modified as appropriate within the scope of the present disclosure.

[0023] In the present disclosure, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0024] In the numerical ranges described in stages in the present disclosure, the upper limit value described in one numerical range may be replaced with the upper limit value of another numerical range described in stages, and the lower limit value described in one numerical range may be replaced with the lower limit value of another numerical range described in stages. In the numerical ranges described in stages in the present disclosure, the upper or lower limit value described in one numerical range may be replaced with a value shown in the examples.

[0025] In the present disclosure, the term "step" encompasses not only an independent step but also a step that cannot be clearly distinguished from other steps as long as the intended purpose is achieved.

[0026] In the present disclosure, when a composition contains multiple substances corresponding to each component, the amount of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified.

[0027] In the present disclosure, combinations of preferred aspects are more preferred aspects.

[0028] In this disclosure, ordinal numbers (e.g., "first" and "second") are terms used to distinguish elements, and do not limit the number of elements or the relative importance of elements.

[0029] <Coordination polymer membrane> A coordination polymer film according to one embodiment of the present disclosure includes a first region including a constitutional unit represented by the following formula (1) or a constitutional unit represented by the following formula (2), and a second region including a constitutional unit represented by the following formula (3) or a constitutional unit represented by the following formula (4).

[0030] [ka]

[0031] In formula (1) and formula (2), M 1 represents a transition metal atom.

[0032] [ka]

[0033] In formula (3) and formula (4), M 2 is the above M 1 That is, M in formula (1) and formula (2) represents a transition metal atom different from the transition metal atom represented by the formula (1). 1 and M in formula (3) and formula (4) 2 is M 1 ≠M 2 Satisfy the relationship.

[0034] According to the above-described embodiment, a coordination polymer film exhibiting rectifying properties is provided. The rectifying properties are presumably due to an energy barrier, such as a Schottky barrier or a pn junction, formed due to the difference in electrical properties between the first region containing the structural unit represented by formula (1) and the second region containing the structural unit represented by formula (2). Therefore, the coordination polymer film can exhibit rectifying properties like a Schottky diode or a pn junction diode.

[0035] [First area] The first region is a region containing a constitutional unit represented by formula (1) or a constitutional unit represented by formula (2). The first region may be a region containing a constitutional unit represented by formula (1). The first region may be a region containing a constitutional unit represented by formula (2).

[0036] In formula (1) and formula (2), M 1 Examples of the transition metal atom represented by the formula include Fe, Co, Ni, Cu, Pd, and Pt. From the viewpoint of rectification properties, M 1 The transition metal atom represented by the formula (I) is preferably Fe, Co, Ni, Cu, Pd or Pt, more preferably Fe, Ni or Cu, and even more preferably Fe or Cu.

[0037] When the coordination polymer film includes a first region containing a constitutional unit represented by formula (1), M 1The transition metal atom represented by formula (2) is preferably Fe, Co, Ni, or Cu, more preferably Fe, Ni, or Cu, and even more preferably Fe or Cu. When the coordination polymer film includes a first region containing a constitutional unit represented by formula (2), M 1 The transition metal atom represented by the formula (I) is preferably Co, Ni, Pd or Pt.

[0038] M 1 Preferred combinations of the type of transition metal atom and the type of structural unit represented by the formula (I) are shown below. Fe: structural unit represented by formula (1) Co: a structural unit represented by formula (1) or a structural unit represented by formula (2) Ni: a structural unit represented by formula (1) or a structural unit represented by formula (2) Cu: a structural unit represented by formula (1) Pd: structural unit represented by formula (2) Pt: structural unit represented by formula (2)

[0039] The constitutional unit represented by formula (1) is preferably a constitutional unit represented by the following formula (1A): The constitutional unit represented by formula (2) is more preferably a constitutional unit represented by the following formula (2A):

[0040] [ka]

[0041] In formula (1A), M 1 is M in the above formula (1). 1 is synonymous with.

[0042] [ka]

[0043] In formula (2A), M 1 is M in the above equation (2). 1 is synonymous with.

[0044] The first region is preferably electrically connected to the second region. "The first region is electrically connected to the second region" means that electrical conductivity is confirmed between the first region and the second region. The electrical conductivity is confirmed by contacting a probe with each of the first region and the second region and measuring the current-voltage characteristics. The first region is preferably directly bonded to the second region. The first region is preferably adjacent to the second region in a direction perpendicular to the thickness direction of the coordination polymer film. At the boundary between the first region and the second region, one ligand (for example, a ligand derived from benzenehexathiol) is preferably M in the above-mentioned formula (1) or formula (2). 1 and M in the above-mentioned formula (3) or formula (4) 2 The first region may be bonded to the second region via another region, as long as electrical conductivity is confirmed.

[0045] From the viewpoint of rectification characteristics, the ratio of the area of ​​the first region to the area of ​​the coordination polymer film in a planar view is preferably 10% or more, more preferably 30% or more, and even more preferably 45% or more. The upper limit of the area of ​​the first region may be determined taking into consideration the area of ​​the second region. The upper limit of the ratio of the area of ​​the first region to the area of ​​the coordination polymer film in a planar view may be 90% or 50%. In the present disclosure, "planar view" means observing an object along the thickness direction of the coordination polymer film.

[0046] Examples of methods for identifying the first region include X-ray photoelectron spectroscopy (XPS), microscopic observation, and elemental mapping. Examples of microscopes include optical microscopes and scanning electron microscopes (SEM). Examples of elemental mapping methods include energy dispersive X-ray spectroscopy (EDS). For example, elemental mapping is measured using a scanning electron microscope equipped with an energy dispersive X-ray detector.

[0047] [Second area] The second region is a region containing a constitutional unit represented by formula (3) or a constitutional unit represented by formula (4). The second region may be a region containing a constitutional unit represented by formula (3). The second region may be a region containing a constitutional unit represented by formula (4).

[0048] In formula (3) and formula (4), M 2 Examples of the transition metal atom represented by the formula include Fe, Co, Ni, Cu, Pd, and Pt. From the viewpoint of rectification properties, M 2 The transition metal atom represented by the formula (I) is preferably Fe, Co, Ni, Cu, Pd or Pt, more preferably Fe, Ni or Cu, and even more preferably Fe or Cu.

[0049] When the coordination polymer film includes a second region containing a constitutional unit represented by formula (3), M 2 The transition metal atom represented by formula (4) is preferably Fe, Co, Ni, or Cu, more preferably Fe, Ni, or Cu, and even more preferably Fe or Cu. When the coordination polymer film includes a second region containing a constitutional unit represented by formula (4), M 2 The transition metal atom represented by the formula (I) is preferably Co, Ni, Pd, or Pd.

[0050] M 2 Preferred combinations of the type of transition metal atom and the type of structural unit represented by the formula (I) are shown below. Fe: structural unit represented by formula (3) Co: a structural unit represented by formula (3) or a structural unit represented by formula (4) Ni: a structural unit represented by formula (3) or a structural unit represented by formula (4) Cu: a structural unit represented by formula (3) Pd: structural unit represented by formula (4) Pt: structural unit represented by formula (4)

[0051] In formula (1) and formula (2), M 1 and a transition metal atom represented by formula (3) and formula (4) 2Preferred combinations with the transition metal atom represented by the formula: 1 and M 2 is M 1 ≠M 2 The following preferable combinations contribute to improving the rectification characteristics. (1) M 1 The transition metal atom represented by is Fe, Co, Ni, Cu, Pd or Pt, and M 2 The transition metal atom represented by is Fe, Co, Ni, Cu, Pd or Pt. (2) M 1 The transition metal atom represented by is Fe, Ni or Cu, and M 2 The transition metal atom represented by is Fe, Ni or Cu. (3) M 1 The transition metal atom represented by is Cu, and M 2 The transition metal atom represented by is Fe.

[0052] The constitutional unit represented by formula (3) is preferably a constitutional unit represented by the following formula (3A): The constitutional unit represented by formula (4) is more preferably a constitutional unit represented by the following formula (4A):

[0053] [ka]

[0054] In formula (3A), M 2 is M in the above equation (3). 2 is synonymous with.

[0055] [ka]

[0056] In formula (4A), M 2 is M in the above equation (4). 2 is synonymous with.

[0057] From the viewpoint of rectification characteristics, the ratio of the area of ​​the second region to the area of ​​the coordination polymer film in a planar view is preferably 10% or more, more preferably 30% or more, and even more preferably 45% or more. The upper limit of the area of ​​the second region may be determined taking into consideration the area of ​​the first region. The upper limit of the ratio of the area of ​​the second region to the area of ​​the coordination polymer film in a planar view may be 90% or 50%.

[0058] From the viewpoint of rectification properties, the ratio of the total area of ​​the first and second regions to the area of ​​the coordination polymer film in a planar view is preferably 30% or more, more preferably 45% or more, and even more preferably 50% or more, and the upper limit of the ratio of the total area of ​​the first and second regions to the area of ​​the coordination polymer film in a planar view may be 100%.

[0059] The second region is identified in accordance with the method for identifying the first region described above.

[0060] [Other Areas] The coordination polymer film may contain other regions within the scope of the present disclosure. The other regions may be conductive regions or insulating regions. The other regions are preferably conductive regions. The other regions may be formed by a coordination polymer. An example of the other regions formed by a coordination polymer is a region containing a constitutional unit represented by formula (5) described below.

[0061] Thickness The thickness of the coordination polymer film is preferably in the range of 1 nm to 1 μm, more preferably in the range of 2 nm to 500 nm, and even more preferably in the range of 5 nm to 100 nm. The average thickness of the coordination polymer film is preferably 1 nm to 1 μm, more preferably in the range of 2 nm to 500 nm, and even more preferably in the range of 5 nm to 100 nm. The average thickness of the coordination polymer film may be 80 μm or less, or 50 μm or less. The average thickness of the coordination polymer film is measured using an atomic force microscope (AFM) in tapping mode.

[0062] [Manufacturing method] The method for producing a coordination polymer film is not limited as long as the desired coordination polymer film can be obtained. In a preferred embodiment, the method for producing a coordination polymer film includes the steps of preparing a coordination polymer film containing a constitutional unit represented by the following formula (5) (hereinafter referred to as "step (1)"), forming a first region containing the constitutional unit represented by the following formula (1) or the constitutional unit represented by the following formula (2) in a part of the coordination polymer film by a metal exchange reaction (hereinafter referred to as "step (2)"), and forming a second region containing the constitutional unit represented by the following formula (3) or the constitutional unit represented by the following formula (4) in a part of the coordination polymer film by a metal exchange reaction (hereinafter referred to as "step (3)").

[0063] [ka]

[0064] [ka]

[0065] In formula (1) and formula (2), M 1 represents a transition metal atom.

[0066] [ka]

[0067] In formula (3) and formula (4), M 2 is M 1 represents a transition metal atom different from the transition metal atom represented by

[0068] (Process (1)) Step (1) is to prepare a coordination polymer film containing a constitutional unit represented by formula (5). Hereinafter, the "coordination polymer film containing a constitutional unit represented by formula (5)" may be referred to as a "precursor film."

[0069] The constitutional unit represented by formula (5) is preferably a constitutional unit represented by the following formula (5A).

[0070] [ka]

[0071] The thickness of the precursor film is preferably in the range of 1 nm to 1 μm, more preferably in the range of 2 nm to 500 nm, and even more preferably in the range of 5 nm to 100 nm. The average thickness of the precursor film is preferably 1 nm to 1 μm, more preferably 2 nm to 500 nm, and even more preferably 5 nm to 100 nm. The average thickness of the precursor film may be 80 μm or less, or 50 μm or less. The average thickness of the precursor film is measured using an atomic force microscope in tapping mode.

[0072] As long as the desired precursor film can be obtained, the method for producing the precursor film is not limited. In a preferred embodiment, the method for producing the precursor film comprises: bringing an organic phase containing benzenehexathiol into contact with an aqueous phase containing a zinc compound; and reacting the benzenehexathiol with the zinc compound at the interface between the organic phase and the aqueous phase to form a coordination polymer film (i.e., precursor film) containing a constitutional unit represented by formula (5).

[0073] Benzenehexathiol may be a commercially available product. Benzenehexathiol may also be produced based on a method described in a known literature. Examples of the literature include "Jennifer A. Harnisch, Robert J. Angelici, Inorganica Chimica Acta, Volumes 300-302, 20 April 2000, Pages 273-279."

[0074] The organic phase preferably further contains a solvent. Examples of the solvent include organic solvents. The organic solvent may be selected from known organic solvents capable of dissolving benzenehexathiol. From the viewpoint of maintaining phase separation between the organic phase and the aqueous phase, the organic phase preferably contains a low-polarity organic solvent. The term "low polarity" used in relation to an organic solvent means a degree of polarity that allows phase separation from water. Examples of low-polarity organic solvents include ethyl acetate, ether (e.g., diethyl ether), petroleum ether, dichloromethane, benzene, toluene, dichloroethane, tetrachloromethane, cyclohexane, chloroform, carbon tetrachloride, and hexane. The organic phase may contain one or more solvents. The proportion of the low-polarity organic solvent in the solvent is preferably 50% or more, more preferably 70% or more, even more preferably 90% or more, and particularly preferably 95% or more, by volume.

[0075] Examples of zinc compounds include Zn(OAc)2·2H2O and Zn(BF4)2·H2O.

[0076] As long as the phase separation between the organic phase and the aqueous phase is maintained, the method for contacting the organic phase and the aqueous phase is not limited. For example, the aqueous phase can be supplied onto the organic phase to contact the organic phase. From the viewpoint of maintaining the phase separation between the organic phase and the aqueous phase and growing a precursor film at the interface between the organic phase and the aqueous phase, it is preferable that the aqueous phase be supplied onto the organic phase to contact the organic phase.

[0077] The precursor film is thought to be formed through the following process. As contact between the organic phase and the aqueous phase continues, a reaction between benzenehexathiol and the zinc compound progresses at the interface between the organic and aqueous phases, and ligands derived from benzenehexathiol coordinate to Zn. As the reaction between benzenehexathiol and the zinc compound spreads in a chain reaction at the interface between the organic and aqueous phases, the ligands derived from benzenehexathiol and Zn are linked together alternately. Through the process described above, the precursor film is formed.

[0078] The reaction temperature between benzenehexathiol and the zinc compound may be determined in consideration of the reaction rate. The reaction temperature may be determined within a range from the freezing point of the solvent to the boiling point of the solvent. The reaction temperature may be 10°C to 90°C. The reaction temperature may be 10°C to 70°C. The reaction temperature may be 20°C to 50°C.

[0079] The reaction time between benzenehexathiol and the zinc compound may be determined in consideration of the growth rate of the precursor film and the target thickness of the precursor film, and may be from 1 second to 1 month.

[0080] Finally, the precursor film is obtained by removing it from the reaction solution. Examples of methods for removing the precursor film include the Langmuir-Schafer method (a method in which a substrate is brought close parallel to the liquid-liquid interface on which the precursor film is formed, and the precursor film is transferred to the substrate). Examples of methods for removing the precursor film include a method in which the precursor film is scooped up with a hard substrate. Examples of methods for removing the precursor film include a method in which the precursor film is placed on a substrate previously placed in a reaction vessel by removing the reaction solution. Examples of the substrate include a silicon substrate.

[0081] (Process (2)) Step (2) is to form a first region containing the constitutional unit represented by the formula (1) or the constitutional unit represented by the formula (2) in a part of the coordination polymer film (i.e., precursor film) by a metal exchange reaction. The metal exchange reaction in step (2) converts a part of Zn contained in the precursor film into M 1 As a result, a first region containing a constitutional unit represented by formula (1) or a constitutional unit represented by formula (2) is formed.

[0082] As a method for the metal exchange reaction in step (2), for example, a part of the precursor film is treated with M 1 Examples of such a method include immersing the metal in a solution containing a compound containing a transition metal atom represented by the formula M 1Examples of compounds containing transition metal atoms represented by the formula include Ni(OAc)2·2H2O, Cu(NO3)2·3H2O, and FeSO4·7H2O. For example, the reaction conditions are determined depending on the progress of the metal exchange reaction. The contact time between the precursor film and the solution is preferably 6 hours to 7 days. The temperature of the solution is preferably 15°C to 50°C.

[0083] (Step (3)) Step (3) is to form a second region containing the constitutional unit represented by the formula (3) or the constitutional unit represented by the formula (4) in a part of the coordination polymer film (i.e., precursor film) by a metal exchange reaction. The metal exchange reaction in step (3) converts a part of Zn contained in the precursor film into M 2 As a result, a second region containing the constitutional unit represented by formula (3) or the constitutional unit represented by formula (4) is formed.

[0084] As a method for the metal exchange reaction in step (3), for example, a part of the precursor film is treated with M 2 Examples of such a method include immersing the metal in a solution containing a compound containing a transition metal atom represented by the formula M 2 Examples of compounds containing transition metal atoms represented by the formula include Ni(OAc)2·2H2O, Cu(NO3)2·3H2O, and FeSO4·7H2O. For example, the reaction conditions are determined depending on the progress of the metal exchange reaction. The contact time between the precursor film and the solution is preferably 6 hours to 7 days. The temperature of the solution is preferably 15°C to 50°C.

[0085] [Application] Coordination polymer films can be applied to various technologies by utilizing their rectifying properties. Applications of coordination polymer films include, for example, various electronic device materials. Specific applications of coordination polymer films include, for example, diodes and light-emitting diodes. [Example]

[0086] Hereinafter, the present disclosure will be described in detail with reference to examples. However, the present disclosure is not limited to the following examples. The matters shown in the following examples may be appropriately changed without departing from the spirit of the present disclosure.

[0087] <Terms> The following abbreviations used in the examples have the following meanings respectively. 「BHT」: Benzenhexathiol 「Zn sheet」: A coordination polymer membrane containing a structural unit represented by formula (5) (i.e., a precursor membrane) 「M 1 / Zn sheet」: A coordination polymer membrane containing a region containing a structural unit represented by formula (1) or a structural unit represented by formula (2) and a region containing a structural unit represented by formula (5) 「M 1 / M 2 sheet」: A coordination polymer membrane containing a region containing a structural unit represented by formula (1) or a structural unit represented by formula (2) and a region containing a structural unit represented by formula (3) or a structural unit represented by formula (4) 「M 1 」: The transition metal atom represented by M 1 in formulas (1) and (2) 「M 2 」: The transition metal atom represented by M 2 in formulas (3) and (4)

[0088] <Synthesis of BHT>​​​​​​​​​Degassed dichloromethane (10 mL) was added to benzenehexathiol (1 mg), and the resulting mixture was shaken thoroughly. The excess benzenehexathiol was then removed by filtration to obtain a saturated aqueous solution of benzenehexathiol (hereinafter referred to as "saturated BHT solution"). All of the following procedures were performed under an argon atmosphere in a glove box. A 2.5 cm × 1.3 cm silicon substrate was suspended at an angle in a 20 mL vial. The surface of the silicon substrate was covered with a 285 nm SiO2 film. Degassed dichloromethane (4 mL) was added to the vial, followed by the saturated BHT solution (4 mL). The vial containing the organic layer (i.e., organic phase) was allowed to stand for 10 minutes. Degassed pure water (4 mL) was layered on top of the organic layer to form an aqueous layer (i.e., aqueous phase). A 0.72 mmol Zn(BF4)2 aqueous solution (4 mL) was carefully added to the aqueous layer. The vial was left standing for 10 minutes, forming a Zn sheet at the interface between the organic and aqueous layers. The organic layer was slowly removed, and the Zn sheet was transferred onto a silicon substrate. Degassed ethanol (4 mL) was carefully placed on top of the aqueous layer, and then all the solvent was removed with a glass pipette. The Zn sheet transferred onto the silicon substrate was washed with degassed CHCl. ​​The Zn sheet was annealed overnight. Using the above procedure, a Zn sheet was prepared.

[0090] [Measuring the thickness of the Zn sheet] The thickness of the Zn sheet was measured using a high amplitude mode (i.e., tapping mode) of an atomic force microscope (specifically, an Agilent Technologies 5500 Scanning Probe Microscope). The thickness of the Zn sheet was 6 nm to 100 nm.

[0091] [Determination of the Zn sheet structure] Zn sheets for structure determination were prepared according to the method previously described. The structure of the Zn sheets was determined by powder X-ray diffraction (PXRD). X-ray diffraction data were obtained by measurements using synchrotron radiation (λ = 0.8 Å) at the BL44B2 beamline of the Superphoton Ring-8 (SPring-8). Structural modeling and PXRD simulations were performed using the VESTA program. These results indicated that a crystal consisting of stacked Zn3BHT structures was formed.

[0092] <Example 2> [M 1 / Zn sheet (M 1 = Ni) All of the following procedures were carried out in an argon atmosphere in a glove box. The silicon substrate coated with the Zn sheet prepared in Example 1 was placed in a 20 mL vial. An aqueous solution of Ni(OAc)2·2H2O was added to the vial, and half of the silicon substrate was immersed in the aqueous solution of Ni(OAc)2·2H2O. The vial was then capped and left to stand for 5 days. Next, the solution in the vial was carefully removed with a pipette, and the silicon substrate was washed with ethanol and dried overnight. By the above procedure, M 1 / Zn sheet (M 1 (=Ni) was prepared. 1 / Zn sheet (M 1 The Ni / Zn sheet is a Ni region (specifically, a region containing a structural unit represented by formula (1) (M 1 =Ni) and a Zn region (specifically, a region including a constitutional unit represented by formula (5)).

[0093] [Observation of Ni / Zn sheet] The Ni / Zn sheet was observed using an optical microscope. A boundary between the colorless Zn region and the black Ni region was observed, indicating a clear junction between the Zn and Ni regions. The shape and size of the Ni / Zn sheet were identical to those of the Zn sheet before the transmetallation reaction. In other words, the geometric structure of the coordination polymer remained unchanged, and only a portion of the Zn in the Zn sheet was replaced by Ni.

[0094] (Elemental analysis of Ni / Zn) Elemental analysis of the Ni region of the Ni / Zn sheet was performed by X-ray photoelectron spectroscopy (XPS). The measurement device was a PHI 5000 VersaProbe (ULVAC-PHI, Inc.), and the X-ray source was AlKα (15 kV, 25 W). 1 / 2 In the narrow-band spectrum of Ni2p, the peak at 1045 eV, which is characteristic of the Zn region, disappeared, and in the narrow-band spectrum of Ni2p, peaks at 854.0 eV and 871.6 eV appeared. This result indicates that some of the zinc(II) ions in the Zn sheet have been replaced by nickel(II) ions. The Ni:S ratio obtained from the heights of the XPS peaks was 1:2.2, which is in close agreement with the ratio in the model structure (i.e., 1:2).

[0095] Example 3 [M 1 / Zn sheet (M 1 Preparation of Cu M was prepared according to the method described in Example 2, except that Ni(OAc)2·2H2O was replaced with Cu(NO3)2·3H2O. 1 / Zn sheet (M 1 = Cu) was prepared. 1 / Zn sheet (M 1 =Cu) is called a "Cu / Zn sheet." The Cu / Zn sheet is a Cu region (i.e., a region containing the structural unit represented by formula (1) (M 1 =Cu) and a Zn region (that is, a region including a constitutional unit represented by formula (5)).

[0096] [Observation of Cu / Zn sheet] The Cu / Zn sheet was observed according to the method described in Example 2. As a result, a boundary between the colorless Zn region and the black Cu region was observed, indicating a clear junction between the Zn and Cu regions. The shape and size of the Cu / Zn sheet were identical to those of the Zn sheet before the transmetallation reaction. In other words, the geometric structure of the coordination polymer remained unchanged, and only a portion of the Zn in the Zn sheet was replaced with Cu.

[0097] [Elemental analysis of Cu / Zn sheet] Elemental analysis of the Cu region of the Cu / Zn sheet was carried out according to the method described in Example 2. Zn2p 1 / 2 In the narrow-band spectrum of , the peak at 1045 eV characteristic of the Zn region disappeared, and in the Cu2p narrow-band spectrum, a peak at 932.5 eV appeared. This result indicates that some of the zinc(II) ions in the Zn sheet have been replaced by copper(II) ions. The Cu:S ratio obtained from the height of the XPS peaks was 1:1.6, which is almost consistent with the ratio in the model structure (i.e., 1:2).

[0098] Example 4 [M 1 / Zn sheet (M 1 =Fe) M was prepared according to the method described in Example 2, except that Ni(OAc)2·2H2O was replaced with FeSO4·7H2O. 1 / Zn sheet (M 1 (=Fe) was prepared. 1 / Zn sheet (M 1 =Fe) is called an "Fe / Zn sheet." The Fe / Zn sheet is a region containing the Fe domain (i.e., the region containing the structural unit represented by formula (1) (M 1 =Fe) and a Zn region (that is, a region including a constitutional unit represented by formula (5)).

[0099] [Observation of Fe / Zn sheet] The Fe / Zn sheet was observed according to the method described in Example 2. As a result, a boundary between the colorless Zn region and the black Fe region was observed, indicating a clear junction between the Zn and Fe regions. The shape and size of the Fe / Zn sheet were identical to those of the Zn sheet before the transmetallation reaction. In other words, the geometric structure of the coordination polymer remained unchanged, and only a portion of the Zn in the Zn sheet was replaced with Fe.

[0100] [Elemental analysis of Fe / Zn sheet] Elemental analysis of the Fe region of the Fe / Zn sheet was carried out according to the method described in Example 2. Zn2p 1 / 2 In the narrow-band spectrum of , the peak at 1045 eV characteristic of the Zn region disappeared, and in the Fe2p narrow-band spectrum, a peak at 710.5 eV appeared. This result indicates that some of the zinc(II) ions in the Zn sheet have been replaced by Fe(II) ions. The Fe:S ratio obtained from the height of the XPS peaks was 1:2.5, which is almost consistent with the ratio in the model structure (i.e., 1:2).

[0101] <Example 5> [M 1 / M 2 Seat (M 1 = Cu, M 2 = Preparation of Fe sheet] All of the following procedures were carried out in an argon atmosphere in a glove box. The silicon substrate coated with the Cu / Zn sheet prepared in Example 3 was placed in a vial. 50 mmol of FeSO4·7H2O aqueous solution was carefully added up to the boundary between the Cu and Zn regions, which was visible to the naked eye, and the Zn region was immersed in the FeSO4·7H2O aqueous solution. The vial was then capped and left to stand for 3 days. The solution in the vial was removed, and the silicon substrate was washed with ethanol and dried. A Cu / Fe sheet was prepared using the above procedure. The thickness of the Cu / Fe sheet measured using the atomic force microscope described above was 6 nm to 100 nm. The Cu / Fe sheet was composed of Cu regions (i.e., regions containing the constitutional unit represented by formula (1) (M 1 =Cu) and the Fe region (i.e., the region containing the structural unit represented by formula (3) (M 2 =Fe). The ratio of the area of ​​the Cu region to the area of ​​the Cu / Fe sheet in a plan view is 50%. The ratio of the area of ​​the Fe region to the area of ​​the Cu / Fe sheet in a plan view is 50%. The ratio of the total area of ​​the Cu region and the Fe region to the area of ​​the Cu / Fe sheet in a plan view is 100%.

[0102] [Elemental analysis of Cu / Fe sheet] Elemental analysis of the Cu / Fe sheet was performed using a JEOL NeoScope JCM7000 equipped with an EDS analyzer. SEM-EDS mapping images showed the absence of zinc (Zn) in the sheet, but the presence of sulfur (S), copper (Cu), and iron (Fe). The S mapping image showed the uniform presence of sulfur (S) throughout the entire sheet. Meanwhile, the Cu mapping image showed the presence of copper (Cu) only in the lower half of the sheet, and the Fe mapping image showed the presence of iron (Fe) only in the upper half of the sheet. These results indicate that the structural units represented by formula (1) and formula (3) are bonded to each other at the boundary between the two regions.

[0103] [Evaluation of electrical properties of Cu / Fe sheets] Four-probe conductivity measurements were performed using an Au tip (ESS Tech Co., Ltd.) connected to a Keithley 2450 source meter. A micromanipulator was placed on a vibration-isolated table, and a four-probe measurement device (Yuzan Co., Ltd.) was placed under an argon atmosphere in a glove box to measure the current-voltage characteristics. The specific procedure is described below.

[0104] Probes 1 and 4 were connected to the Fe region, and probes 2 and 3 were connected to the Cu region. In optical micrographs of each probe placed on a Cu / Fe sheet, the boundary between the Cu and Fe regions can be visualized by utilizing the contrast difference due to the difference in metals. Current-voltage measurements between two probes were performed in six combinations (1-2, 2-1, 3-4, 4-3, 1-3, 1-4, and 2-3). In each of the six combinations, the first number represents the probe (source) number, and the second number represents the probe (drain) number.

[0105] In the combinations (1-2 and 4-3) where one probe (source) was connected to the Fe region and the other probe (drain) was connected to the Cu region, rectification characteristics were observed, with small current values ​​at positive voltages and large current values ​​at negative voltages. The results for combination "1-2" are shown in Figure 1. In the combinations (2-1 and 3-4) where the source and drain probe positions were reversed, rectification characteristics were observed, with large current values ​​at positive voltages and small current values ​​at negative voltages. The results for combination "2-1" are shown in Figure 2.

[0106] On the other hand, in the combination (1-4) where two probes were connected to the Fe region and the combination (2-3) where two probes were connected to the Cu region, the same amount of current flowed at both positive and negative voltages, and no rectification characteristics were observed. The results for combination "1-4" are shown in Figure 3. The results for combination "2-3" are shown in Figure 4.

[0107] The above results indicate the rectifying properties resulting from the junction between the Cu and Fe regions of the Cu / Fe sheet.

Claims

1. A coordination polymer film comprising: a first region including a constitutional unit represented by the following formula (1) or a constitutional unit represented by the following formula (2); and a second region including a constitutional unit represented by the following formula (3) or a constitutional unit represented by the following formula (4). 【Chemistry 1】 In formula (1) and formula (2), M １ represents Cu. 【Chemistry 2】 In formula (3) and formula (4), M ２ represents Fe.

2. Preparing a coordination polymer film containing a constitutional unit represented by the following formula (5); forming a first region including a constitutional unit represented by the following formula (1) or a constitutional unit represented by the following formula (2) in a part of the coordination polymer film by a metal exchange reaction; and forming a second region containing a constitutional unit represented by the following formula (3) or a constitutional unit represented by the following formula (4) in a part of the coordination polymer film by a metal exchange reaction: Method for producing coordination polymer membranes. 【Transformation 3】 【Chemistry 4】 In formula (1) and formula (2), M １ represents a transition metal atom. 【Transformation 5】 In formula (3) and formula (4), M ２ is the M １ represents a transition metal atom different from the transition metal atom represented by the formula:

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