Method for producing carbon monoxide, carbon dioxide reduction electrode, carbon dioxide reduction apparatus, and modified metal complex

Abstract

The present invention provides a method for producing carbon monoxide with excellent carbon dioxide reduction efficiency, a carbon dioxide reduction electrode, a carbon dioxide reduction apparatus, and a modified metal complex. [Solution] A method for producing carbon monoxide, comprising reacting carbon dioxide with water in the presence of a modified metal complex obtained from a mixture containing a polynuclear metal complex represented by the following formula (1) and a conductive material. JPEG2026114682000101.jpg6371

Description

[Technical Field]

[0001] This disclosure relates to a method for producing carbon monoxide, a carbon dioxide reduction electrode, a carbon dioxide reduction apparatus, and a modified metal complex. [Background technology]

[0002] Metal complexes are used as catalysts. For example, Patent Document 1 discloses the use of a binuclear complex represented by a specific structural formula and a metal complex obtained by thermally modifying it as an electrode catalyst for a fuel cell.

[0003] Furthermore, metal complexes are also known to be used as catalysts for carbon dioxide reduction in methods that produce carbon monoxide by reducing carbon dioxide. For example, Patent Document 2 discloses the use of a porous electrode containing a heat-modified mononuclear metal complex in a carbon dioxide reduction device. Non-Patent Document 1 describes the use of a nickel-containing binuclear complex for the reduction of carbon dioxide. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2009-173627 [Patent Document 2] International Publication No. 2019 / 065258 [Non-patent literature]

[0005] [Non-Patent Document 1] Y. Xiao et al., “Bioinspired Binickel Catalyst for Carbon Dioxide Reduction: The Importance of Metal-ligand Cooperation”, JACS Au 2024, 4, 1207-1218 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, knowledge about catalysts that offer superior reduction efficiency in methods for producing carbon monoxide by reducing carbon dioxide has been limited. For example, Patent Document 1 relates only to a binuclear complex represented by a specific structural formula, and does not specifically disclose a method for producing carbon monoxide by reducing carbon dioxide. The mononuclear metal complex described in Patent Document 2 was not sufficient, as its carbon dioxide reduction efficiency was low even after modification treatment. The dinuclear complex described in Non-Patent Document 1 tended to have higher reduction efficiency than mononuclear metal complexes, but its reduction efficiency for carbon dioxide was not sufficient.

[0007] This disclosure is made in view of the above, and relates to a method for producing carbon monoxide with excellent carbon dioxide reduction efficiency, a carbon dioxide reduction electrode, a carbon dioxide reduction apparatus, and a modified metal complex. [Means for solving the problem]

[0008] This disclosure includes the following aspects: <1> A method for producing carbon monoxide, comprising reacting carbon dioxide with water in the presence of a modified metal complex obtained from a mixture containing a polynuclear metal complex represented by the following formula (1) and a conductive material.

[0009] [ka] (In formula (1), R represents a hydrogen atom or substituent, and any multiple Rs may be the same or different, and two adjacent Rs may be bonded to each other to form a ring structure, and P represents a divalent group containing one or more aromatic rings, Q 1 and Q 2 Q represents a monovalent group containing one or more aromatic rings. 1 and Q 2They may be combined with each other to form a ring structure. M represents a cobalt atom, a nickel atom, or a zinc atom. a is an integer from 2 to 4. The plurality of Ms may be the same or different from each other. X is a counter ion or a neutral molecule. b is an integer of 0 or more. When there are a plurality of Xs, the plurality of Xs may be the same or different from each other. O is an oxygen atom and is bonded to at least one M.) <2> The method for producing carbon monoxide according to <1>, wherein the modified metal complex is obtained by subjecting the mixture to heat treatment, radiation irradiation treatment, or discharge treatment. <3> The method for producing carbon monoxide according to <2>, wherein the heat treatment, radiation irradiation treatment, or discharge treatment is performed so that the mass reduction rate calculated by the following formula (A) is 1% to 90%. Mass reduction rate (%) = [((Total mass of polynuclear metal complex and conductive material before treatment) - (Total mass of polynuclear metal complex and conductive material after treatment)) / (Total mass of polynuclear metal complex and conductive material before treatment)] × 100 …(A) <4> In the above formula (1), P is a divalent group represented by the following formula (P a ), formula (P b ), or formula (P c ). The method for producing carbon monoxide according to any one of <1> to <3>.

[0010]

Chemical formula

[0011] [ka] (Formula(P c1 ) ~ expression (P c3 ), R p (where * represents a hydrogen atom or substituent, and * represents a bond.) <5> The aforementioned polynuclear metal complex is a compound represented by the following formula (2): <1> ~ <3> A method for producing carbon monoxide as described in any one of the following.

[0012] [ka] (In formula (2), R 6 ~R 8 R represents a hydrogen atom or substituent, and there are multiple R 6 ~R 8 These can be the same or different, and the two adjacent Rs 6 Two adjacent Rs 7 Two Rs that are adjacent to each other 8 They may bond to each other to form a ring structure, Q 3 and Q 4 Q represents a monovalent group containing one or more aromatic rings. 3 and Q4 The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, a is an integer between 2 and 4, and multiple M atoms may be the same or different, X is a counterion or neutral molecule, b is an integer greater than or equal to 0, and if there are multiple X atoms, they may be the same or different, and O is an oxygen atom that bonds to at least one M atom. <6> In the above equation (1), P is given by the following equation (P a ) or formula (P b It is a divalent group represented by Q 1 and Q 2 The formula is as follows (Q a ) or formula (Q b A monovalent group represented by ) <1> ~ <3> A method for producing carbon monoxide as described in any one of the following.

[0013] [ka] (Formula(P a ), R 1 and R 2 R represents a hydrogen atom or substituent, and there are multiple R 1 and R 2 These can be the same or different, and the two adjacent Rs 1 Two Rs that are adjacent to each other 2 These elements may bond to each other to form a ring structure. Formula (P b ), R 3 and R 4 R represents a hydrogen atom or substituent, and there are multiple R 3 These can be the same or different, and the two adjacent Rs 3 R adjacent to each other 3 and R 4 These elements may bond to each other to form a ring structure. Formula (P a ) and formula (P b (In the above, * represents a bonding operation.)

[0014] [ka] (Formula(Q a ) and (Q b ), R q R represents a hydrogen atom or substituent, and there are multiple R q These can be the same or different, and the two adjacent Rs q These elements may bond to each other to form a ring structure, and * represents a bonding hand. <7> The aforementioned polynuclear metal complex is a compound represented by the following formula (3): <1> ~ <3> A method for producing carbon monoxide as described in any one of the following.

[0015] [ka] (In formula (3), R 9 ~R 13 R represents a hydrogen atom, substituent, or divalent group, and there are multiple R 9 ~R 12 These can be the same or different, and the two adjacent Rs 9 Two adjacent Rs 10 Two adjacent Rs 11 Two adjacent Rs 12 R, both adjacent to each other 12 and R 13 They may bond to each other to form a ring structure, R 13 If is a divalent group, it may combine with other compounds represented by formula (3) to form a dimer, where M represents a cobalt atom, a nickel atom, or a zinc atom, and multiple Ms may be the same or different, where X is a counterion or a neutral molecule, where b is a non-negative integer, and if there are multiple Xs, they may be the same or different. <8> The aforementioned polynuclear metal complex is a compound represented by the following formula (4): <1> ~ <3> A method for producing carbon monoxide as described in any one of the following.

[0016] [ka] (In formula (4), R 14 ~R 16 represents a hydrogen atom or a substituent, and a plurality of R 14 ~R 16 may be the same or different from each other, and two adjacent R 14 s, two adjacent R 15 s, and adjacent R 15 and R 16 may be bonded to each other to form a ring structure. M represents a cobalt atom, a nickel atom, or a zinc atom, and a plurality of M may be the same or different from each other. X is a counter ion or a neutral molecule, b is an integer of 0 or more, and when there are a plurality of X, the plurality of X may be the same or different from each other.) <9> The method for producing carbon monoxide according to any one of <1> to <3>, wherein the polynuclear metal complex is a compound represented by the following formula (5).

[0017]

Chemical formula

[0018]

Chemical formula

[0019] [ka] (In formula (7), R 27 ~R 34 R represents a hydrogen atom or substituent, and there are multiple R 27 ~R 34 These can be the same or different, and the two adjacent Rs 27 Two adjacent Rs 28 Two adjacent Rs 29 Two adjacent Rs 30 Two adjacent Rs 31 Two adjacent Rs 32 Two adjacent Rs 33 Two Rs that are adjacent to each other 34The elements may bond to each other to form a ring structure; Ar represents a divalent aromatic group which may have substituents; M represents a cobalt atom, a nickel atom, or a zinc atom; a is an integer between 2 and 4, and multiple Ms may be the same or different; X is a counterion or neutral molecule; b is an integer greater than or equal to 0, and if there are multiple Xs, they may be the same or different; O is an oxygen atom which is bonded to at least one M. <12> The aforementioned polynuclear metal complex is a compound represented by the following formula (8): <1> ~ <3> A method for producing carbon monoxide as described in any one of the following.

[0020] [ka] (In formula (8), Z represents an alkylene group or an arylene group, and the multiple Zs may be the same or different, R 35 R represents a hydrogen atom or substituent, and there are multiple R 35 These can be the same or different, and the two adjacent Rs 35 They may bond to each other to form a ring structure, and Y is given by the following formula (P c1 ), formula (P c2 ), or formula (P c3 ) represents a compound, where multiple Ys may be the same or different, M represents a cobalt atom, a nickel atom, or a zinc atom, where multiple Ms may be the same or different, X is a counterion or neutral molecule, b is a non-negative integer, and if there are multiple Xs, each X may be the same or different.

[0021] [ka] (Formula(P c1 ) ~ expression (P c3 ), R p (where * represents a hydrogen atom or substituent, and * represents a bond.) <13> A carbon dioxide reduction electrode comprising a modified metal complex obtained from a mixture containing a polynuclear metal complex represented by the following formula (1) and a conductive material.

[0022] [ka] (In formula (1), R represents a hydrogen atom or substituent, and any multiple Rs may be the same or different, and two adjacent Rs may be bonded to each other to form a ring structure, and P represents a divalent group containing one or more aromatic rings, Q 1 and Q 2 Q represents a monovalent group containing one or more aromatic rings. 1 and Q 2 The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, a is an integer between 2 and 4, and multiple M atoms may be the same or different, X is a counterion or neutral molecule, b is an integer greater than or equal to 0, and if there are multiple X atoms, they may be the same or different, and O is an oxygen atom that bonds to at least one M atom. <14> The support further comprises the modified metal complex, <13> The carbon dioxide reduction electrode described above. <15> Further containing an ionic conductor, <13> or <14> The carbon dioxide reduction electrode described above. <16> Oxidizing electrode and, <13> ~ <15> A carbon dioxide reduction electrode as described in any one of the following, A membrane separating the oxidizing electrode and the carbon dioxide reduction electrode, Electrolyte and The system comprises a power supply connected to the oxidizing electrode and the carbon dioxide reduction electrode, Carbon dioxide reduction device. <17> A modified metal complex obtained from a mixture containing a polynuclear metal complex represented by the following formula (6).

[0023] [ka] (In formula (6), R22 ~R 26 R represents a hydrogen atom or substituent, and there are multiple R 22 ~R 26 These can be the same or different, and the two adjacent Rs 22 Two adjacent Rs 23 Two adjacent Rs 24 Two adjacent Rs 26 R, both adjacent to each other 25 and R 26 The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, and multiple M atoms may be the same or different, X is a counterion or neutral molecule, b is a non-negative integer, and if there are multiple X atoms, they may be the same or different. <18> The mixture further comprises a conductive material. <17> Modified metal complex as described above. <19> A modified metal complex obtained from a mixture containing a polynuclear metal complex represented by the following formula (10).

[0024] [ka] (In formula (10), R represents a hydrogen atom or a substituent, and multiple Rs may be the same or different, and two adjacent Rs may bond to each other to form a ring structure, R 3 and R 4 R represents a hydrogen atom or substituent, and there are multiple R 3 These can be the same or different, and the two adjacent Rs 3 R adjacent to each other 3 and R 4 They may bond to each other to form a ring structure, Q 1 and Q 2 The formula is as follows (Q a ) or formula (Q b) represents a monovalent group, where M represents a cobalt atom, nickel atom, or zinc atom, a is an integer from 2 to 4, and multiple Ms may be the same or different, X is a counterion or neutral molecule, b is an integer of 0 or more, and if there are multiple Xs, they may be the same or different, and O is an oxygen atom that is bonded to at least one M.

[0025] [ka] (Formula(Q a ) and (Q b ), R q R represents a hydrogen atom or substituent, and there are multiple R q These can be the same or different, and the two adjacent Rs q These elements may bond to each other to form a ring structure, and * represents a bonding hand. <20> The mixture further comprises a conductive material. <19> Modified metal complex as described above. <21> The method involves reacting carbon dioxide with water in the presence of a modified metal complex obtained from a mixture containing a polynuclear metal complex and a conductive material. The aforementioned polynuclear metal complex contains at least one metal atom selected from the group consisting of cobalt atoms, nickel atoms, and zinc atoms, and the distance between the metal atoms calculated by density functional theory is less than 3.18 Å. A method for producing carbon monoxide. <22> The aforementioned polynuclear metal complex is a polynuclear metal complex in which one metal atom and two oxygen atoms are coordinately bonded. <21> A method for producing carbon monoxide as described above. [Effects of the Invention]

[0026] According to this disclosure, a method for producing carbon monoxide with excellent carbon dioxide reduction efficiency, a carbon dioxide reduction electrode, a carbon dioxide reduction apparatus, and a modified metal complex are provided. [Brief explanation of the drawing]

[0027] [Figure 1]Figure 1 is a schematic cross-sectional view showing an example of a carbon dioxide reduction electrode according to this disclosure. [Figure 2] Figure 2 is a schematic cross-sectional view showing an example of the carbon dioxide reduction apparatus of this disclosure. [Modes for carrying out the invention]

[0028] The following describes an example of an embodiment of this disclosure. These descriptions and examples are illustrative and do not limit the scope of the invention. In numerical ranges described stepwise within this specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described stepwise. Furthermore, in numerical ranges described within this specification, the upper or lower limit of that range may be replaced with the values ​​shown in the examples.

[0029] Each component may contain multiple types of the relevant substance. When referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of those multiple substances present in the composition. The term "process" includes not only independent processes, but also any process that cannot be clearly distinguished from other processes, as long as its intended function is achieved.

[0030] Examples of "substituents" include halogen atoms, alkyl groups (including cycloalkyl groups), alkenyl groups, alkynyl groups, alkoxy groups, alkylthio groups, aryl groups, aryloxy groups, divalent oxo groups, arylthio groups, monovalent heterocyclic groups, substituted amino groups, acyl groups, imine residues, amide groups, acidimide groups, substituted oxycarbonyl groups, cyano groups, alkylsulfonyl groups, and nitro groups. In this specification, when referring to the number of carbon atoms, the number of carbon atoms of substituents is usually not included.

[0031] An "aromatic hydrocarbon ring group" refers to the group of atoms remaining after removing one or more hydrogen atoms that are directly bonded to the carbon atoms constituting an aromatic hydrocarbon ring, which may be unsubstituted or substituted, and which may consist of two or more fused rings.

[0032] An "aromatic heterocyclic group" refers to the group of atoms remaining after removing one or more hydrogen atoms directly bonded to a carbon or heteroatom that constitutes an aromatic heterocyclic ring, which may be unsubstituted or substituted, and in which two or more rings are fused.

[0033] In compound names, "t-" means tertiary, "n-" means normal, and "p-" means para. In chemical structural formulas, the dotted lines represent parts that may be single or double bonds.

[0034] ≪Carbon Monoxide Production Method A≫ A method for producing carbon monoxide according to the present disclosure (hereinafter also referred to as "production method A") involves reacting carbon dioxide with water in the presence of a modified metal complex obtained from a mixture containing a polynuclear metal complex represented by the following formula (1) and a conductive material.

[0035] [ka]

[0036] In formula (1), R represents a hydrogen atom or substituent, and any multiple Rs may be the same or different, and two adjacent Rs may be bonded to each other to form a ring structure, and P represents a divalent group containing one or more aromatic rings, Q 1 and Q 2 Q represents a monovalent group containing one or more aromatic rings. 1 and Q 2The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, a is an integer from 2 to 4, and multiple M atoms may be the same or different, X is a counterion or neutral molecule, b is an integer of 0 or more, and if there are multiple X atoms, multiple X atoms may be the same or different, and O is an oxygen atom that is bonded to at least one M atom.

[0037] According to manufacturing method A of this disclosure, the carbon dioxide reduction efficiency is excellent. The manufacturing method A of the present disclosure uses a modified metal complex obtained from a mixture containing a polynuclear metal complex represented by formula (1) and a conductive material as a catalyst. Here, although the detailed mechanism is unknown, it is presumed that the polynuclear metal complex represented by formula (1) exhibits high carbon monoxide selectivity because, due to its binuclear structure with adjacent central metals and the coordination environment to the central metal by macrocyclic ligands, hydrogen generation is suppressed and carbon monoxide production by reduction of carbon dioxide is promoted. Furthermore, the polynuclear metal complex represented by formula (1) becomes a modified metal complex having a structure in which the nitrogen and metal atoms of the polynuclear metal complex are immobilized in the conductive material while maintaining some of the structure of the complex. It is presumed that carbon dioxide is reduced by coordinating with the cobalt, nickel, and / or zinc atoms of the modified metal complex, and that carbon monoxide is produced with high selectivity. In other words, since the modified metal complex of this disclosure is a modified metal complex obtained by modifying a polynuclear metal complex having a specific chemical structure and metal atoms represented by formula (1), it is presumed that the structure of the central metal and the coordination environment to the central metal in the modified metal complex are optimized, and the reduction reaction of carbon dioxide proceeds rapidly.

[0038] <Polynuclear metal complex represented by formula (1)> The manufacturing method A of this disclosure uses a modified metal complex obtained from a mixture containing a polynuclear metal complex represented by the following formula (1) and a conductive material.

[0039] [ka]

[0040] In formula (1), R represents a hydrogen atom or substituent, and any multiple Rs may be the same or different, and two adjacent Rs may be bonded to each other to form a ring structure, and P represents a divalent group containing one or more aromatic rings, Q 1 and Q 2 Q represents a monovalent group containing one or more aromatic rings. 1 and Q 2 The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, a is an integer from 2 to 4, and multiple M atoms may be the same or different, X is a counterion or neutral molecule, b is an integer of 0 or more, and if there are multiple X atoms, multiple X atoms may be the same or different, and O is an oxygen atom that is bonded to at least one M atom.

[0041] [R] In formula (1) above, R is preferably a hydrogen atom, an alkyl group, or an alkoxy group. If R is an alkyl group, it is more preferably an alkyl group having 1 to 10 carbon atoms (also called "carbon number"), and even more preferably a t-butyl group. If R is an alkoxy group, it is more preferably an alkoxy group having 1 to 10 carbon atoms, and even more preferably a methoxy group. In formula (1) above, from the viewpoint of reduction efficiency, it is preferable that the R at the para position with respect to the bonded position of the oxygen atom is an alkyl group or an alkoxy group. Furthermore, in formula (1), from the viewpoint of reduction efficiency, it is preferable that both R atoms at the meta positions relative to the bonded position of the oxygen atom are hydrogen atoms.

[0042] [[M] a ] From the viewpoint of reduction efficiency, M is preferably a nickel atom or a cobalt atom, and more preferably a nickel atom. Furthermore, from the viewpoint of reduction efficiency, M is preferably a divalent nickel atom or a divalent cobalt atom, and more preferably a divalent nickel atom. The polynuclear metal complex may be a heterogeneous metal complex. From the viewpoint of reduction efficiency, M is preferably a combination of nickel atoms and zinc atoms, or a combination of cobalt atoms and zinc atoms.

[0043] a is preferably 2 or 4, and more preferably 2. In other words, the polynuclear metal complex is preferably a dinuclear complex (also called a "binuclear complex").

[0044] [[X] b ] The counterion represented by X is preferably an anion, and more preferably at least one anion selected from the group consisting of fluoride ions, chloride ions, bromide ions, iodide ions, sulfide ions, oxide ions, hydroxide ions, hydride ions, sulfite ions, phosphate ions, cyanide ions, acetate ions, 2-ethylhexanoate ions, carbonate ions, sulfate ions, nitrate ions, bicarbonate ions, trifluoroacetate ions, thiocyanide ions, trifluoromethanesulfonate ions, acetylacetonate, tetrafluoroborate ions, hexafluorophosphate ions, and tetraphenylborate ions. The neutral molecule represented by X is preferably at least one neutral molecule selected from the group consisting of water, methanol, ethanol, n-propanol, isopropyl alcohol, 2-methoxyethanol, 1,1-dimethylethanol, ethylene glycol, N,N'-dimethylformamide, N,N'-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, acetone, chloroform, acetonitrile, benzonitrile, triethylamine, pyridine, pyrazine, diazabicyclo[2,2,2]octane, 4,4'-bipyridine, tetrahydrofuran, diethyl ether, dimethoxyethane, methyl ethyl ether, 1,4-dioxane, acetic acid, propionic acid, and 2-ethylhexanoic acid.

[0045] b is preferably an integer between 0 and 8, and more preferably between 0 and 4.

[0046] [O] In the above formula (1), O is preferably bonded to two M's.

[0047] [P] In the above formula (1), the aromatic ring contained in P includes an aromatic hydrocarbon ring group and an aromatic heterocyclic group. From the viewpoint of reduction efficiency, the aromatic heterocyclic group is preferably an aromatic heterocyclic group containing a nitrogen atom or an aromatic heterocyclic group containing a sulfur atom, more preferably an aromatic heterocyclic group containing a nitrogen atom, and particularly preferably an aromatic heterocyclic group of a five-membered or six-membered ring containing a nitrogen atom. Also, from the viewpoint of reduction efficiency, P is preferably a divalent group containing two or more aromatic rings, and more preferably a divalent group containing two aromatic rings. Furthermore, from the viewpoint of reduction efficiency, P is preferably a divalent group represented by the following formula (P a ), formula (P b ), or formula (P c ).

[0048]

Chemical formula

[0049] In formula (P a ), R 1 and R 2 represent a hydrogen atom or a substituent, and a plurality of R 1 and R 2 may be the same or different from each other, and two adjacent R 1 and two adjacent R 2 may be bonded to each other to form a ring structure. In formula (P b ), R 3 and R 4 represent a hydrogen atom or a substituent, and a plurality of R 3 may be the same or different from each other, and two adjacent R 3 as well as two adjacent R 3 and R 4 may be bonded to each other to form a ring structure. In formula (P c ), R 5 represents a hydrogen atom or a substituent, and a plurality of R 5 may be the same or different from each other. Y represents the following formula (P c1 ), formula (P c2 ), or formula (P c3 ), and a plurality of Y may be the same or different from each other. Z represents an alkylene group or an arylene group. In formula (P a ) to formula (P c ), * represents a bond.

[0050]

Chemical formula

[0051] <00管理、コントロール、制御、調整、支配、操作、運営、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する、操作する、運営する、管理する、支配する、管理する、制御する、調整する動作を行う。式(P c1 )~式(P c3 )中、R<000019 / >は水素原子又は置換基を表し、*は結合手を表す。

[0052] (Formula (P a )) [[ID=4 / In the above formula (P a ), it is preferable that R 2 is a hydrogen atom.

[0053] (Formula (P b )) In the above formula (P b ), it is preferable that R 3 is a hydrogen atom. In the above formula (P​​​​​​​​​b ), R 4 The ring group is preferably an aromatic hydrocarbon ring group, more preferably an unsubstituted or substituted aromatic hydrocarbon group having 30 or fewer carbon atoms, even more preferably an unsubstituted or substituted phenyl group, an unsubstituted or substituted naphthyl group, an unsubstituted or substituted anthryl group, or an unsubstituted or substituted pyrenyl group, and particularly preferably an unsubstituted or substituted phenyl group. Specific examples of substituents include halogen atoms such as fluorine, chlorine, bromine, and iodine, hydroxyl groups, carboxyl groups, ester groups, mercapto groups, sulfonic acid groups, nitro groups, phosphonic acid groups, silyl groups having C1-C4 alkyl groups, methyl groups, ethyl groups, propyl groups, isopropyl groups, cyclopropyl groups, butyl groups, isobutyl groups, tert-butyl groups, pentyl groups, cyclopentyl groups, hexyl groups, cyclohexyl groups, norbonyl groups, nonyl groups, cyclononyl groups, and decyl groups. Examples include monovalent monovalent saturated hydrocarbon groups with approximately 1 to 50 carbon atoms, such as 3,7-dimethyloctyl group, adamantyl group, dodecyl group, cyclododecyl group, pentadecyl group, octadecyl group, and docosyl group; and monovalent monovalent alkoxy groups with approximately 1 to 50 carbon atoms, such as alkenyl group, alkynyl group, methoxy group, ethoxy group, propiooxy group, butoxy group, pentyloxy group, cyclohexyloxy group, norbonyloxy group, decyloxy group, and dodecyloxy group. The number of substituents can be any number that is substituted, such as 1 to 5 for phenyl groups, 1 to 7 for naphthyl groups, and 1 to 9 each for anthryl and pyrenyl groups.

[0054] (Formula(P c )) The above formula (P c ), R 5 It is preferably a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, or an alkylthio group, and more preferably a hydrogen atom or an alkyl group. R 5 If R is an alkyl group, 5It is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and even more preferably a methyl group or a t-butyl group. R 5 If R is an aryl group, 5 The group is preferably an aryl group having 6 to 14 carbon atoms, and more preferably a phenyl group. R 5 If R is an alkoxy group, 5 It is preferably an alkoxy group having 1 to 10 carbon atoms, more preferably an alkoxy group having 1 to 4 carbon atoms, and even more preferably a methoxy group. R 5 If R is an alkylthio group, 5 It is preferably an alkylthio group having 1 to 10 carbon atoms, more preferably an alkylthio group having 1 to 4 carbon atoms, and even more preferably a methylthio group. The above formula (P c In the formula (P c1 ) or formula (P c2 ) is more preferable, formula (P c1 ) is even more preferable. Equation (P c2 ), R p It is preferable that it is a hydrogen atom. The above formula (P c In this combination, Z is preferably an alkylene group having 2 to 6 carbon atoms or an arylene group having 4 to 14 carbon atoms, more preferably an arylene group having 4 to 14 carbon atoms, and even more preferably an arylene group having 6 to 10 carbon atoms. If Z is an alkylene group, it is preferable that Z is a 1,3-propylene group. The arylene group in Z may be a divalent hydrocarbon aromatic group or a divalent heteroaromatic group. When Z is an arylene group, Z is preferably a phenylene group, pyridinediyl group, tetrafluorophenylene group, naphthalenediyl group, thiophenediyl group, dimethylphenylene group, or phenanthrenediyl group, more preferably a 1,2-phenylene group, 3,4-pyridinediyl group, 3,4,5,6-tetrafluoro-1,2-phenylene group, 2,3-naphthalenediyl group, 3,4-thiophenediyl group, 3,4-dimethyl-1,2-phenylene group, or 9,10-phenanthrenediyl group, and particularly preferably a 1,2-phenylene group.

[0055] [Q 1 Q 2 ] In equation (1) above, Q 1 and Q 2 Aromatic rings included in the monovalent group represented by include aromatic hydrocarbon ring groups and aromatic heterocyclic ring groups. 1 and Q 2 The aromatic heterocyclic group contained in the monovalent group represented by is preferably an aromatic heterocyclic group containing a nitrogen atom or an aromatic heterocyclic group containing a sulfur atom. 1 and Q 2 When these atoms are bonded to each other to form a ring structure, it is preferable that this ring structure is, for example, the remaining atomic group after removing two hydrogen atoms from phenanthroline.

[0056] Q 1 and Q 2 This is expressed by the following formula (Q a ) or formula (Q b It is preferable that the group is a monovalent group represented by ).

[0057] [ka]

[0058] Formula (Q a ) and (Q b ), R q R represents a hydrogen atom or substituent, and there are multiple R qmay be the same or different, and two adjacent Rs q may be bonded to each other to form a ring structure, and * represents a bond.

[0059] In the formula (Q a ) and (Q b ), R q is preferably a hydrogen atom or a hydrocarbon group, more preferably a hydrogen atom or an alkyl group or alkenyl group having 1 to 6 carbon atoms, and still more preferably a hydrogen atom. Two adjacent Rs q may be bonded to each other to form a ring structure, and two adjacent Rs q The ring structure formed by bonding to each other is preferably a benzene ring.

[0060] From the viewpoint of reduction efficiency, in formula (1), P is a divalent group represented by formula (P a ) or formula (P b ), and Q 1 and Q 2 are preferably a combination of monovalent groups represented by formula (Q a ) or formula (Q b ).

[0061] <Polynuclear metal complex represented by formula (2)> From the viewpoint of reduction efficiency, the polynuclear metal complex is preferably a compound represented by the following formula (2).

[0062]

Chemical formula

[0063] In formula (2), R 6 ~ R 8 represents a hydrogen atom or a substituent, and a plurality of Rs 6 ~ R 8 may be the same or different, and two adjacent Rs 6 with each other, two adjacent Rs 7 with each other, and two adjacent Rs 8 with each other may be bonded to each other to form a ring structure, and Q3 and Q 4 Q represents a monovalent group containing one or more aromatic rings. 3 and Q 4 The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, a is an integer from 2 to 4, and multiple M atoms may be the same or different, X is a counterion or neutral molecule, b is an integer of 0 or more, and if there are multiple X atoms, multiple X atoms may be the same or different, and O is an oxygen atom that is bonded to at least one M atom.

[0064] [R 6 ~R 8 ] In equation (2) above, R 6 R is preferably a hydrogen atom, an alkyl group, or an alkoxy group. 6 If it is an alkyl group, it is more preferably an alkyl group having 1 to 10 carbon atoms, and even more preferably a t-butyl group. 6 If the group is an alkoxy group, it is more preferably an alkoxy group having 1 to 10 carbon atoms, and even more preferably a methoxy group. Furthermore, in formula (2) above, from the viewpoint of reduction efficiency, the two R atoms at the para position relative to the bond position of the oxygen atom 6 It is preferably a substituent, more preferably an alkyl group or an alkoxy group, and even more preferably an alkyl group. Furthermore, in formula (2) above, from the viewpoint of reduction efficiency, the four R's at the meta position relative to the bond position of the oxygen atom 6 It is preferable that it be a hydrogen atom. In equation (2) above, R 7 It is preferably a hydrogen atom or a hydrocarbon group, more preferably a hydrogen atom or an alkyl group or alkenyl group having 1 to 6 carbon atoms, and even more preferably a hydrogen atom or an alkenyl group having 1 to 4 carbon atoms. Two adjacent R 7 It is preferable that the elements are bonded to each other to form a ring structure, and two adjacent R elements 7 The ring structure formed by the bonding of these elements is preferably a benzene ring. In equation (2) above, R 8 It is preferable that it is a hydrogen atom.

[0065] [Q 3 Q 4 ] In equation (2) above, Q 3 and Q 4 Aromatic rings included in the monovalent group represented by include aromatic hydrocarbon ring groups and aromatic heterocyclic ring groups. 3 and Q 4 The aromatic heterocyclic group contained in the monovalent group represented by is preferably an aromatic heterocyclic group containing a nitrogen atom or an aromatic heterocyclic group containing a sulfur atom. 3 and Q 4 When these atoms are bonded to each other to form a ring structure, it is preferable that this ring structure is, for example, the remaining atomic group after removing two hydrogen atoms from phenanthroline.

[0066] Q 3 and Q 4 This is expressed by the following formula (Q a ) or formula (Q b It is preferable that the group is a monovalent group represented by ).

[0067] [ka]

[0068] Formula (Q a ) and (Q b ), R q R represents a hydrogen atom or substituent, and there are multiple R q These can be the same or different, and the two adjacent Rs q These elements may be bonded to each other to form a ring structure, and * represents a bonding hand.

[0069] Formula (Q a ) and (Q b ), R qIt is preferably a hydrogen atom or a hydrocarbon group, more preferably a hydrogen atom or an alkyl group or alkenyl group having 1 to 6 carbon atoms, and even more preferably a hydrogen atom. Two adjacent R q They may be bonded to each other to form a ring structure, and two adjacent R q The ring structure formed by the bonding of these elements is preferably a benzene ring.

[0070] [[M] a [X] b ,O] In the above formula (2), [M] a [X] b A preferred embodiment of , and O is [M] in formula (1) a [X] b , and are identical to the preferred embodiment of O.

[0071] <Polynuclear metal complex represented by formula (3)> From the viewpoint of reduction efficiency, the polynuclear metal complex is preferably a compound represented by the following formula (3).

[0072] [ka]

[0073] In formula (3), R 9 ~R 13 R represents a hydrogen atom, substituent, or divalent group, and there are multiple R 9 ~R 12 These can be the same or different, and the two adjacent Rs 9 Two adjacent Rs 10 Two adjacent Rs 11 Two adjacent Rs 12 R, both adjacent to each other 12 and R 13 They may bond to each other to form a ring structure, R 13If is a divalent group, the divalent group may combine with other compounds represented by formula (3) above to form a dimer, M represents a cobalt atom, a nickel atom, or a zinc atom, and multiple Ms may be the same or different, X is a counterion or a neutral molecule, b is an integer of 0 or more, and if there are multiple Xs, multiple Xs may be the same or different.

[0074] [R 9 ~R 13 ] In the above equation (3), R 9 R is preferably a hydrogen atom, an alkyl group, or an alkoxy group. 9 If it is an alkyl group, it is more preferably an alkyl group having 1 to 10 carbon atoms, and even more preferably a t-butyl group. 9 If the group is an alkoxy group, it is more preferably an alkoxy group having 1 to 10 carbon atoms, and even more preferably a methoxy group. Furthermore, in formula (3) above, from the viewpoint of reduction efficiency, the two R atoms at the para position relative to the bond position of the oxygen atom 9 It is preferably a substituent, more preferably an alkyl group or an alkoxy group, and even more preferably an alkyl group. Furthermore, in formula (3) above, from the viewpoint of reduction efficiency, the four R's at the meta position relative to the bond position of the oxygen atom 9 It is preferable that it be a hydrogen atom. In the above equation (3), R 10 It is preferably a hydrocarbon group, more preferably an alkyl group or alkenyl group having 1 to 6 carbon atoms, and even more preferably an alkenyl group having 1 to 4 carbon atoms. Two adjacent R 10 It is preferable that the elements are bonded to each other to form a ring structure, and two adjacent R elements 10 The ring structure formed by the bonding of these elements is preferably a benzene ring. In the above equation (3), R 11 It is preferable that it is a hydrogen atom. In the above equation (3), R 12 It is preferable that it is a hydrogen atom. In the above equation (3), R 13 The ring group is preferably an aromatic hydrocarbon ring group, more preferably an unsubstituted or substituted aromatic hydrocarbon group having 30 or fewer carbon atoms, even more preferably an unsubstituted or substituted phenyl group, an unsubstituted or substituted naphthyl group, an unsubstituted or substituted anthryl group, or an unsubstituted or substituted pyrenyl group, and particularly preferably an unsubstituted or substituted phenyl group. Specific examples of substituents include halogen atoms such as fluorine, chlorine, bromine, and iodine, hydroxyl groups, carboxyl groups, ester groups, mercapto groups, sulfonic acid groups, nitro groups, phosphonic acid groups, silyl groups having C1-C4 alkyl groups, methyl groups, ethyl groups, propyl groups, isopropyl groups, cyclopropyl groups, butyl groups, isobutyl groups, tert-butyl groups, pentyl groups, cyclopentyl groups, hexyl groups, cyclohexyl groups, norbonyl groups, nonyl groups, cyclononyl groups, and decyl groups. Examples include monovalent monovalent saturated hydrocarbon groups with approximately 1 to 50 carbon atoms, such as 3,7-dimethyloctyl group, adamantyl group, dodecyl group, cyclododecyl group, pentadecyl group, octadecyl group, and docosyl group; and monovalent monovalent alkoxy groups with approximately 1 to 50 carbon atoms, such as alkenyl group, alkynyl group, methoxy group, ethoxy group, propiooxy group, butoxy group, pentyloxy group, cyclohexyloxy group, norbonyloxy group, decyloxy group, and dodecyloxy group. The number of substituents can be any number that is substituted, such as 1 to 5 for phenyl groups, 1 to 7 for naphthyl groups, and 1 to 9 each for anthryl and pyrenyl groups. Also, in formula (3) above, R 13 If the group is divalent, the divalent group may combine with another compound molecule, which is a compound represented by formula (3) and is different from the compound molecule containing the divalent group, to form a dimer.

[0075] [M, X] b ] In the above formula (3), M and [X] b A preferred embodiment of is M and [X] in formula (1) bThis is identical to the preferred embodiment.

[0076] <Polynuclear metal complex represented by formula (4)> From the viewpoint of reduction efficiency, the polynuclear metal complex is preferably a compound represented by the following formula (4).

[0077] [ka]

[0078] In formula (4), R 14 ~R 16 R represents a hydrogen atom or substituent, and there are multiple R 14 ~R 16 These can be the same or different, and the two adjacent Rs 14 Two adjacent Rs 15 R, both adjacent to each other 15 and R 16 The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, and multiple M atoms may be the same or different, X is a counterion or a neutral molecule, b is a non-negative integer, and if there are multiple X atoms, multiple X atoms may be the same or different.

[0079] [R 14 ~R 16 ] In equation (4) above, R 14 R is preferably a hydrogen atom, an alkyl group, or an alkoxy group. 14 If it is an alkyl group, it is more preferably an alkyl group having 1 to 10 carbon atoms, and even more preferably a t-butyl group. 14 If the group is an alkoxy group, it is more preferably an alkoxy group having 1 to 10 carbon atoms, and even more preferably a methoxy group. Furthermore, in formula (4) above, from the viewpoint of reduction efficiency, the two R atoms at the para position relative to the bond position of the oxygen atom 14 It is preferably a substituent, more preferably an alkyl group or an alkoxy group, and even more preferably an alkyl group. Furthermore, in formula (4) above, from the viewpoint of reduction efficiency, the four R's at the meta position relative to the bond position of the oxygen atom 14 It is preferable that it be a hydrogen atom. In equation (4) above, R 15 It is preferable that it is a hydrogen atom. In equation (4) above, R 16 The ring group is preferably an aromatic hydrocarbon ring group, more preferably an unsubstituted or substituted aromatic hydrocarbon group having 30 or fewer carbon atoms, even more preferably an unsubstituted or substituted phenyl group, an unsubstituted or substituted naphthyl group, an unsubstituted or substituted anthryl group, or an unsubstituted or substituted pyrenyl group, and particularly preferably an unsubstituted or substituted phenyl group. Specific examples of substituents include halogen atoms such as fluorine, chlorine, bromine, and iodine, hydroxyl groups, carboxyl groups, ester groups, mercapto groups, sulfonic acid groups, nitro groups, phosphonic acid groups, silyl groups having C1-C4 alkyl groups, methyl groups, ethyl groups, propyl groups, isopropyl groups, cyclopropyl groups, butyl groups, isobutyl groups, tert-butyl groups, pentyl groups, cyclopentyl groups, hexyl groups, cyclohexyl groups, norbonyl groups, nonyl groups, cyclononyl groups, and decyl groups. Examples include monovalent monovalent saturated hydrocarbon groups with approximately 1 to 50 carbon atoms, such as 3,7-dimethyloctyl group, adamantyl group, dodecyl group, cyclododecyl group, pentadecyl group, octadecyl group, and docosyl group; and monovalent monovalent alkoxy groups with approximately 1 to 50 carbon atoms, such as alkenyl group, alkynyl group, methoxy group, ethoxy group, propiooxy group, butoxy group, pentyloxy group, cyclohexyloxy group, norbonyloxy group, decyloxy group, and dodecyloxy group. The number of substituents can be any number that is substituted, such as 1 to 5 for phenyl groups, 1 to 7 for naphthyl groups, and 1 to 9 each for anthryl and pyrenyl groups.

[0080] [M, X] b ] In the above formula (4), M and [X] b A preferred embodiment of is M and [X] in formula (1)b This is identical to the preferred embodiment.

[0081] <Polynuclear metal complex represented by formula (5)> From the viewpoint of reduction efficiency, the polynuclear metal complex is preferably a compound represented by the following formula (5).

[0082] [ka]

[0083] In formula (5), R 17 ~R 21 R represents a hydrogen atom or substituent, and there are multiple R 17 ~R 21 These can be the same or different, and the two adjacent Rs 17 Two adjacent Rs 18 Two adjacent Rs 19 Two adjacent Rs 20 Two Rs that are adjacent to each other 21 These atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, X is a counterion or a neutral molecule, b is a non-negative integer, and if there are multiple X atoms, each X atom may be the same or different.

[0084] [R 17 ~R 21 ] In equation (5) above, R 17 R is preferably a hydrogen atom, an alkyl group, or an alkoxy group. 17 If it is an alkyl group, it is more preferably an alkyl group having 1 to 10 carbon atoms, and even more preferably a t-butyl group. 17 If the group is an alkoxy group, it is more preferably an alkoxy group having 1 to 10 carbon atoms, and even more preferably a methoxy group. In equation (5) above, R 18It is preferably a hydrocarbon group, more preferably an alkyl group or alkenyl group having 1 to 6 carbon atoms, and even more preferably an alkenyl group having 1 to 4 carbon atoms. Two adjacent R 18 It is preferable that the elements are bonded to each other to form a ring structure, and two adjacent R elements 18 The ring structure formed by the bonding of these elements is preferably a benzene ring. In equation (5) above, R 19 It is preferable that it is a hydrogen atom. In equation (5) above, R 20 It is preferably a hydrocarbon group, more preferably an alkyl group or alkenyl group having 1 to 6 carbon atoms, and even more preferably an alkenyl group having 1 to 4 carbon atoms. Two adjacent R 20 It is preferable that the elements are bonded to each other to form a ring structure, and two adjacent R elements 20 The ring structure formed by the bonding of these elements is preferably a benzene ring. In equation (5) above, R 21 It is preferable that it is a hydrogen atom.

[0085] [M, X] b ] In the above formula (5), M and [X] b A preferred embodiment of is M and [X] in formula (1) b This is identical to the preferred embodiment.

[0086] <Polynuclear metal complex represented by formula (6)> From the viewpoint of reduction efficiency, the polynuclear metal complex is preferably a compound represented by the following formula (6).

[0087] [ka]

[0088] In formula (6), R 22 ~R 26 R represents a hydrogen atom or substituent, and there are multiple R 22 ~R 26These can be the same or different, and the two adjacent Rs 22 Two adjacent Rs 23 Two adjacent Rs 24 Two adjacent Rs 26 R, both adjacent to each other 25 and R 26 The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, and multiple M atoms may be the same or different, X is a counterion or a neutral molecule, b is a non-negative integer, and if there are multiple X atoms, multiple X atoms may be the same or different.

[0089] [R 22 ~R 26 ] In the above formula (6), R 22 R is preferably a hydrogen atom, an alkyl group, or an alkoxy group. 22 If it is an alkyl group, it is more preferably an alkyl group having 1 to 10 carbon atoms, and even more preferably a t-butyl group. 22 If the group is an alkoxy group, it is more preferably an alkoxy group having 1 to 10 carbon atoms, and even more preferably a methoxy group. In the above formula (6), R 23 It is preferably a hydrocarbon group, more preferably an alkyl group or alkenyl group having 1 to 6 carbon atoms, and even more preferably an alkenyl group having 1 to 4 carbon atoms. Two adjacent R 23 It is preferable that the elements are bonded to each other to form a ring structure, and two adjacent R elements 23 The ring structure formed by the bonding of these elements is preferably a benzene ring. In the above formula (6), R 24 and R 25 It is preferable that it is a hydrogen atom. In the above formula (6), R 26 It is preferably a hydrocarbon group, more preferably an alkyl group or alkenyl group having 1 to 6 carbon atoms, and even more preferably an alkenyl group having 1 to 4 carbon atoms. Two adjacent R26 It is preferable that the elements are bonded to each other to form a ring structure, and two adjacent R elements 26 The ring structure formed by the bonding of these elements is preferably a benzene ring.

[0090] [M, X] b ] In the above formula (6), M and [X] b A preferred embodiment of is M and [X] in formula (1) b This is identical to the preferred embodiment.

[0091] <Polynuclear metal complex represented by formula (7)> From the viewpoint of reduction efficiency, the polynuclear metal complex is preferably a compound represented by the following formula (7).

[0092] [ka]

[0093] In formula (7), R 27 ~R 34 R represents a hydrogen atom or substituent, and there are multiple R 27 ~R 34 These can be the same or different, and the two adjacent Rs 27 Two adjacent Rs 28 Two adjacent Rs 29 Two adjacent Rs 30 Two adjacent Rs 31 Two adjacent Rs 32 Two adjacent Rs 33 Two Rs that are adjacent to each other 34 The elements may bond to each other to form a ring structure, Ar represents a divalent aromatic group which may have substituents, M represents a cobalt atom, a nickel atom, or a zinc atom, a is an integer from 2 to 4, and multiple Ms may be the same or different, X is a counterion or a neutral molecule, b is an integer of 0 or more, and if there are multiple Xs, multiple Xs may be the same or different, and O is an oxygen atom which is bonded to at least one M.

[0094] [R 27 ~R 34 ] In equation (7) above, R 27 and R 31 R is preferably a hydrogen atom, an alkyl group, or an alkoxy group. 27 and R 31 If it is an alkyl group, it is more preferably an alkyl group having 1 to 10 carbon atoms, and even more preferably a t-butyl group. 27 and R 31 If the group is an alkoxy group, it is more preferably an alkoxy group having 1 to 10 carbon atoms, and even more preferably a methoxy group. In equation (7) above, R 28 It is preferably a hydrocarbon group, more preferably an alkyl group or alkenyl group having 1 to 6 carbon atoms, and even more preferably an alkenyl group having 1 to 4 carbon atoms. Two adjacent R 28 It is preferable that the elements are bonded to each other to form a ring structure, and two adjacent R elements 28 The ring structure formed by the bonding of these elements is preferably a benzene ring. In equation (7) above, R 32 It is preferably a hydrocarbon group, more preferably an alkyl group or alkenyl group having 1 to 6 carbon atoms, and even more preferably an alkenyl group having 1 to 4 carbon atoms. Two adjacent R 32 It is preferable that the elements are bonded to each other to form a ring structure, and two adjacent R elements 32 The ring structure formed by the bonding of these elements is preferably a benzene ring. In equation (7) above, R 29 and R 33 It is preferable that it is a hydrogen atom. In equation (7) above, R 30 and R 34 It is preferable that it is a hydrogen atom.

[0095] [[M] a ] In formula (7), the preferred embodiment of M is the same as the preferred embodiment of M in formula (1). In formula (7) above, a is preferably 4.

[0096] [[X] b ,O] In the above equation (7), [X] b A preferred embodiment of and O is [X] in formula (1) b And is identical to the preferred embodiment of O.

[0097] [Ar] In formula (7), Ar can be an aromatic hydrocarbon ring group or an aromatic heterocyclic group. From the viewpoint of reduction efficiency, the aromatic heterocyclic group is preferably an aromatic heterocyclic group containing a nitrogen atom or an aromatic heterocyclic group containing a sulfur atom, more preferably an aromatic heterocyclic group containing a nitrogen atom, and particularly preferably a five-membered or six-membered aromatic heterocyclic group containing a nitrogen atom. Furthermore, from the viewpoint of reduction efficiency, Ar is preferably a divalent group containing one or more aromatic rings, and more preferably a divalent group containing one aromatic ring.

[0098] <Polynuclear metal complex represented by formula (8)> From the viewpoint of reduction efficiency, the polynuclear metal complex is preferably a compound represented by the following formula (8).

[0099] [ka]

[0100] In formula (8), Z represents an alkylene group or an arylene group, and the multiple Zs may be the same or different, R 35 R represents a hydrogen atom or substituent, and there are multiple R 35 These can be the same or different, and the two adjacent Rs 35 They may bond to each other to form a ring structure, and Y is given by the following formula (P c1 ), formula (P c2 ), or formula (P c3) represents a cobalt atom, nickel atom, or zinc atom, and multiple Ms may be the same or different. X is a counterion or neutral molecule, b is a non-negative integer, and if there are multiple Xs, multiple Xs may be the same or different.

[0101] [ka]

[0102] Formula (P c1 ) ~ expression (P c3 ), R p * represents a hydrogen atom or substituent, and * represents a bond.

[0103] [Z] In formula (8) above, Z is preferably an alkylene group having 2 to 6 carbon atoms or an arylene group having 4 to 14 carbon atoms, more preferably an arylene group having 4 to 14 carbon atoms, and even more preferably an arylene group having 6 to 10 carbon atoms, from the viewpoint of reduction efficiency. If Z is an alkylene group, it is preferable that Z is a 1,3-propylene group. The arylene group in Z may be a divalent hydrocarbon aromatic group or a divalent heteroaromatic group. When Z is an arylene group, Z is preferably a phenylene group, pyridinediyl group, tetrafluorophenylene group, naphthalenediyl group, thiophenediyl group, dimethylphenylene group, or phenanthrenediyl group, more preferably a 1,2-phenylene group, 3,4-pyridinediyl group, 3,4,5,6-tetrafluoro-1,2-phenylene group, 2,3-naphthalenediyl group, 3,4-thiophenediyl group, 3,4-dimethyl-1,2-phenylene group, or 9,10-phenanthrenediyl group, and particularly preferably a 1,2-phenylene group.

[0104] [R 35 ] In equation (8) above, R 35From the viewpoint of reduction efficiency, it is preferably a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, or an alkylthio group, and more preferably a hydrogen atom or an alkyl group. R 35 If R is an alkyl group, 35 It is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and even more preferably a methyl group or a t-butyl group. R 35 If R is an aryl group, 35 The group is preferably an aryl group having 6 to 14 carbon atoms, and more preferably a phenyl group. R 35 If R is an alkoxy group, 35 It is preferably an alkoxy group having 1 to 10 carbon atoms, more preferably an alkoxy group having 1 to 4 carbon atoms, and even more preferably a methoxy group. R 35 If R is an alkylthio group, 35 It is preferably an alkylthio group having 1 to 10 carbon atoms, more preferably an alkylthio group having 1 to 4 carbon atoms, and even more preferably a methylthio group.

[0105] [Y] In formula (8) above, Y is preferably the same group from the viewpoint of reduction efficiency, and formula (P c1 It is more preferable that it be ) Y is given by equation (P c2 ) If R p From the viewpoint of reduction efficiency, it is preferable that it be a hydrogen atom.

[0106] [M, X] b ] In formula (8), preferred embodiments of M and X are the same as preferred embodiments of M and X in formula (1). In formula (8) above, b is preferably an integer between 0 and 4, more preferably an integer between 0 and 2, and particularly preferably 2.

[0107] <Polynuclear metal complex represented by formula (11)> From the viewpoint of reduction efficiency, the polynuclear metal complex is preferably a compound represented by the following formula (11).

[0108] [ka]

[0109] In formula (11), Ar 1 and Ar 2 Each of these independently represents an arylene group, R 35 R represents a hydrogen atom or substituent, and there are multiple R 35 These can be the same or different, and the two adjacent Rs 35 They may bond to each other to form a ring structure, and Y is given by the following formula (P c1 ), formula (P c2 ), or formula (P c3 ) represents a θ such that any multiple Ys may be the same or different, X is a counterion or neutral molecule, b is a non-negative integer, and if there are multiple Xs, any multiple Xs may be the same or different.

[0110] [ka]

[0111] Formula (P c1 ) ~ expression (P c3 ), R p * represents a hydrogen atom or substituent, and * represents a bond.

[0112] [Ar 1 Ar 2 ] Ar in equation (11) 1 and Ar 2 From the viewpoint of ease of synthesis and reduction efficiency, it is preferable that these be the same group. Also, in equation (11) Ar 1 and Ar 2Each of these groups is preferably an arylene group having 4 to 14 carbon atoms, and more preferably an arylene group having 6 to 10 carbon atoms, from the viewpoint of reduction efficiency. Ar 1 and Ar 2 The arylene group in this compound may be a divalent hydrocarbon aromatic group or a divalent heteroaromatic group. Ar 1 and Ar 2 Specifically, preferred groups include phenylene, pyridinediyl, tetrafluorophenylene, naphthalenediyl, thiophenediyl, dimethylphenylene, and phenanthrenediyl; more preferred groups include 1,2-phenylene, 3,4-pyridinediyl, 3,4,5,6-tetrafluoro-1,2-phenylene, 2,3-naphthalenediyl, 3,4-thiophenediyl, 3,4-dimethyl-1,2-phenylene, and 9,10-phenanthrenediyl; and particularly preferred is the 1,2-phenylene group.

[0113] [R 35 , M, [X] b ,Y] In formula (11), R 35 , M, [X] b A preferred embodiment of Y is R in formula (8). 35 , M, [X] b , and are identical to the preferred embodiment of Y.

[0114] <Polynuclear metal complex represented by formula (12)> From the viewpoint of reduction efficiency, the polynuclear metal complex is preferably a compound represented by the following formula (12).

[0115] [ka]

[0116] In formula (12), Ar 1 and Ar 2 Each of these is an independently independent arylene group, R 36R represents a hydrogen atom, alkyl group, alkoxy group, or alkylthio group, and there are multiple R 36 These may be the same or different, R 37 R represents a hydrogen atom, alkyl group, or aryl group, and there are multiple R 37 These may be the same or different, R 38 R represents a hydrogen atom, alkyl group, or aryl group, and there are multiple R 38 Each of the elements may be the same or different, X is a counterion or neutral molecule, b is a non-negative integer, and if there are multiple X's, each of the multiple X's may be the same or different.

[0117] [R 36 ~R 38 ] The two R's in equation (12) 36 From the viewpoint of ease of synthesis and reduction efficiency, it is preferable that these be the same group. Also, R in equation (12) 36 From the viewpoint of reduction efficiency, it is preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, even more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and particularly preferably a hydrogen atom or a t-butyl group. The four R's in equation (12) 37 From the viewpoint of ease of synthesis and reduction efficiency, it is preferable that these be the same group. Also, R in equation (12) 37 From the viewpoint of reduction efficiency, it is preferably a hydrogen atom, an alkyl group, or an aryl group; more preferably a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms; even more preferably a hydrogen atom, a methyl group, or a phenyl group; and particularly preferably a hydrogen atom. The four R's in equation (12) 38 From the viewpoint of ease of synthesis and reduction efficiency, it is preferable that these be the same group. Also, R in equation (12) 38From the viewpoint of reduction efficiency, it is preferably a hydrogen atom, an alkyl group, or an aryl group; more preferably a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms; even more preferably a hydrogen atom, a methyl group, or a phenyl group; and particularly preferably a hydrogen atom.

[0118] [Ar 1 Ar 2 , M, [X] b ,Y] Ar in equation (12) 1 and Ar 2 A preferred embodiment is Ar in formula (11). 1 and Ar 2 This is identical to the preferred embodiment. M, [X] in equation (12) b A preferred embodiment of , and Y is M, [X] in formula (8) b , and are identical to the preferred embodiment of Y.

[0119] <Specific structural formula of the polynuclear metal complex represented by formula (1)> The following shows, but is not limited to, the specific structural formula of the polynuclear metal complex represented by formula (1). In the following structural formula, "Me" represents a methyl group, "Et" represents an ethyl group, "t-Bu" means a t-butyl group, "TMS" represents a trimethylsilyl group, and "i-Pr" means an isopropyl group. - "OAc" stands for acetate anion, M represents a cobalt atom, a nickel atom, or a zinc atom, and multiple Ms may be the same or different, and the valence of M is divalent (M 2+ )

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[0148] <Modified metal complex> In the manufacturing method A of this disclosure, the modified metal complex is obtained from a mixture containing a polynuclear metal complex represented by formula (1) and a conductive material. Preferably, the modified metal complex is obtained by modifying the mixture containing the polynuclear metal complex represented by formula (1) and the conductive material. By modifying the mixture, the polynuclear metal complex represented by formula (1) is also modified. In other words, modified metal complexes are polynuclear metal complexes whose carbon dioxide reduction efficiency has been increased through modification treatment.

[0149] It is thought that modified metal complexes undergo a mass reduction accompanied by low-molecular-weight detachment upon modification treatment, and that ligands react with each other and with the conductive material, leading to condensation accompanied by low-molecular-weight detachment. Then, within the modified ligand formed by condensation, it is thought that the metal atoms maintain a spatial arrangement almost identical to that of the original multinuclear metal complex, resulting in a stable coordination structure.

[0150] Here, it is preferable that the modified ligand is in a condensed and linked state in a graphene-like structure, as this increases its stability against acids and alkalis and its thermal stability. A "graphene-like structure" refers to a two-dimensional carbon hexagonal network structure in which carbon atoms are chemically bonded by sp2 hybrid orbitals, and some of the carbon atoms constituting the graphene-like structure may be replaced with heteroatoms such as nitrogen. Alternatively, the modified ligand may take the form of a graphite-like structure in which the aforementioned graphene-like structures are stacked.

[0151] A processed product containing a modified metal complex obtained from a mixture of a polynuclear metal complex represented by formula (1) and a conductive material may contain unreacted polynuclear metal complexes or metal nanoparticles or metal oxides generated by the decomposition of the polynuclear metal complex after the modification treatment. In such cases, the modified metal complex is obtained by removing the metal nanoparticles or metal oxides by acid treatment or the like, but the processed product obtained by the modification treatment can be used as a catalyst as is, as long as it does not impair the function of the modified metal complex.

[0152] Furthermore, the cobalt, nickel, and zinc atoms that may be included in the modified metal complex may be uncharged or charged ions, but from the viewpoint of catalytic activity, they are preferably divalent cobalt, divalent nickel, and divalent zinc atoms, more preferably divalent cobalt and divalent nickel atoms, and even more preferably divalent nickel atoms.

[0153] [Mixture] (Polynuclear metal complex represented by formula (1)) The polynuclear metal complex represented by formula (1) contained in the mixture is as described above, and it is possible to use only one type of polynuclear metal complex or two or more types of polynuclear metal complexes.

[0154] (Conductive materials) The conductive material included in the mixture can be any known material without particular limitation, as long as it is capable of supporting the polynuclear metal complex. The conductive material may be a flat or rod-shaped carbonaceous material or metallic material, or a porous carbonaceous material or metallic material such as carbon paper or metal mesh. The conductive material may also be a powder material such as carbon black (CB) or metal particles. Only one type of conductive material may be used, or two or more types of conductive materials may be used.

[0155] There are no particular restrictions on the conductive material, but a porous carbon material is preferred. Examples of conductive materials include carbon particles such as Norlit, Ketjenblack, Vulcan, Black Pearl, and Acetylene Black; fullerenes such as C60 and C70; carbon nanotubes; carbon nanohorns; carbon fibers; graphene; graphene oxide; reduced graphene oxide; Knobel; and graphene mesosponges.

[0156] A mixture containing a polynuclear metal complex represented by formula (1) and a conductive material may be a mixture in which the polynuclear metal complex represented by formula (1) is supported on a conductive material. The method of support is not particularly limited, and any known method can be arbitrarily applied. Examples include a method of vacuum deposition of the polynuclear metal complex represented by formula (1) onto a conductive material (also called a conductive carrier), a method of immersing a conductive material in a solution in which the polynuclear metal complex represented by formula (1) is dissolved or dispersed in a solvent, ultrasonically treating it, and drying it, a method of coating a conductive material with a solution in which the polynuclear metal complex represented by formula (1) is dissolved or dispersed in a solvent, and a method of adding a powdered conductive material to a solution in which the polynuclear metal complex represented by formula (1) is dissolved or dispersed in a solvent, adsorbing the polynuclear metal complex represented by formula (1) onto the surface of the powder, concentrating or filtering the solution, and then drying it.

[0157] Alternatively, a mixture may be obtained by molding a mixture in which the polynuclear metal complex represented by formula (1) is supported on a powdered conductive material by compression or concentration to dryness. Or, a mixture in which the polynuclear metal complex represented by formula (1) is supported on a powdered conductive material may be immobilized on a support such as a flat plate, rod, grid, or porous carbonaceous material or metal material.

[0158] The amount of the polynuclear metal complex represented by formula (1) in the mixture is preferably such that the total mass of cobalt atoms, nickel atoms, and zinc atoms relative to the mass of the conductive material is 1% by mass or more and 50% by mass or less, and more preferably 1% by mass or more and 10% by mass or less.

[0159] In the mixture, the mass of the polynuclear metal complex represented by formula (1) is preferably 1% by mass or more and 100% by mass or less relative to the mass of the conductive material, and more preferably 5% by mass or more and 50% by mass or less.

[0160] The mass of metal atoms (cobalt, nickel, and zinc atoms) relative to the mass of the conductive material is measured using a thermomass / differential thermal analyzer (TG-DTA). The measurement method is as follows: This can be performed by using a thermal mass / differential thermal analyzer to measure the TG-DTA curve while heating the temperature from below 25°C to 900°C in air at a heating rate of 10°C / min.

[0161] The mixture may contain other components besides the polynuclear metal complex represented by formula (1) and the conductive material. Other components include solvents, ligands for polynuclear metal complexes represented by formula (1), mononuclear metal complexes, polynuclear metal complexes other than those represented by formula (1), organic compounds with a boiling or melting point of 200°C or higher, and organic compounds with a thermal polymerization initiation temperature of 250°C or lower.

[0162] Examples of solvents include chloroform, methanol, ethanol, and mixtures thereof.

[0163] Examples of organic compounds having a boiling or melting point of 200°C or higher include perylene-3,4,9,10-tetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic diimide, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic diimide, 1,4,5,8-naphthalenetetracarboxylic acid, pyromellitic acid, and aromatic compound carboxylic acid derivatives such as pyromellitic dianhydride. The structural formulas of these compounds are as described in paragraphs

[0115] to

[0116] of Japanese Patent Publication No. 2009-173627.

[0164] Here, the boiling point or melting point can be measured using known methods and selected from the measured values, but it can also be selected using values ​​described in literature, etc. Furthermore, the boiling point or melting point may be a calculated value obtained through computer simulation, for example, a calculated boiling point or melting point registered in SciFinder (version 2007.2), software provided by the Chemical Abstract Service, may also be used.

[0165] Organic compounds with a thermal polymerization initiation temperature of 250°C or lower are organic compounds that have double or triple bonds in addition to aromatic rings. Examples include organic compounds such as acenaphthylene and vinylnaphthalene described in paragraph

[0118] of Japanese Patent Publication No. 2009-173627. The thermal polymerization initiation temperature is described in "Fundamentals of Carbonization Engineering" (1st edition, 2nd printing, 1982, Ohmsha).

[0166] [Pre-processing] It is particularly preferable to dry the mixture for at least 6 hours at a temperature of 15°C to 200°C under a reduced pressure of 1 kPa or less as a pretreatment before the modification treatment. A vacuum dryer or the like can be used for this pretreatment.

[0167] [Modification process] The modification treatment of the mixture is preferably carried out in the presence of a reducing atmosphere such as hydrogen or carbon monoxide, an oxidizing atmosphere such as oxygen, carbon dioxide, or water vapor, an inert gas atmosphere such as nitrogen, helium, neon, argon, krypton, or xenon, a nitrogen-containing compound gas or vapor such as ammonia or acetonitrile, or a mixture thereof. More preferably, in a reducing atmosphere, hydrogen and a mixture of hydrogen and the aforementioned inert gas are used; in an oxidizing atmosphere, oxygen and a mixture of oxygen and the aforementioned inert gas are used; and in an inert gas atmosphere, nitrogen, neon, argon, and a mixture of these gases are used. The pressure used in the heat treatment is not particularly limited, but it is preferably around atmospheric pressure of about 0.5 to 1.5 atmospheres. The pressure used in the modification process can be appropriately changed during the selected modification process.

[0168] When a mixture containing a conductive material supported with a polynuclear metal complex represented by formula (1) is subjected to a modification treatment, a conductive material supported with a modified metal complex is obtained.

[0169] Modified metal complexes are preferably obtained by heat treatment, radiation treatment, or electrical discharge treatment of the mixture.

[0170] (Heat treatment) The heat treatment temperature for the mixture should be a temperature that sufficiently denatures the polynuclear metal complex to achieve excellent reduction efficiency while maintaining the complex structure. Preferably, it is 250°C or higher, more preferably 300°C or higher, even more preferably 400°C or higher, and may be 500°C or higher or 600°C or higher. The heat treatment temperature is preferably 1200°C or lower, more preferably 1000°C or lower, even more preferably 800°C or lower, and may be 700°C or lower or 600°C or lower. For example, the heat treatment temperature is 250°C to 1200°C. The heat treatment temperature may be set depending on the type of polynuclear metal complex.

[0171] The processing time for the heat treatment can be appropriately set depending on the gas used and the temperature, but the temperature may be gradually raised from room temperature in a sealed or ventilated state of the gas, and then immediately lowered after reaching the target temperature. In particular, it is preferable to gradually heat the mixture by maintaining the temperature after reaching the target temperature, as this can further improve durability. The holding time after reaching the target temperature is preferably 0.5 hours to 100 hours, more preferably 0.5 hours to 40 hours, even more preferably 1 hour to 10 hours, and especially preferably 1 to 5 hours.

[0172] Examples of equipment used for heat treatment include tubular furnaces, ovens, heating furnaces, and induction hot plates.

[0173] (Radiation treatment, electrical discharge treatment) Alternative modification treatments to heat treatment can be selected from radiation irradiation treatment using any radiation selected from electromagnetic waves or particle beams such as alpha rays, beta rays, neutron rays, electron beams, gamma rays, X-rays, vacuum ultraviolet rays, ultraviolet rays, visible light, infrared rays, microwaves, radio waves, and lasers; discharge treatments such as corona discharge treatment, glow discharge treatment, and plasma treatment (including low-temperature plasma treatment). Among these, preferred modification treatments include radiation irradiation treatment using radiation selected from X-rays, electron beams, ultraviolet rays, visible light, infrared rays, microwaves, and lasers, as well as low-temperature plasma treatment. More preferably, the treatment is radiation irradiation treatment using radiation selected from ultraviolet rays, visible light, infrared rays, microwaves, and lasers. These methods can be carried out in accordance with the equipment and processing methods commonly used for surface modification of polymer films. For example, methods described in literature (e.g., "Chemistry of Surface Analysis and Modification," edited by the Adhesion Society of Japan, Nikkan Kogyo Shimbun, published December 19, 2003) can be used.

[0174] (mass reduction rate) From the viewpoint of sufficiently modifying the polynuclear metal complex to achieve excellent reduction efficiency while maintaining the complex structure, the modification treatment (e.g., heat treatment, radiation treatment, or discharge treatment) is preferably performed under conditions arbitrarily set so that the mass reduction rate calculated by the following formula (A) is 1% to 90%, more preferably 1% to 80%, even more preferably 1% to 50%, particularly preferably 2% to 30%, and most preferably 2% to 15%. Mass reduction rate (%) = [(Total mass of polynuclear metal complex and conductive material before treatment) - (Total mass of polynuclear metal complex and conductive material after treatment) / (Total mass of polynuclear metal complex and conductive material before treatment)] × 100 …(A)

[0175] By processing the material so that the mass loss rate falls within the above range, the catalytic activity of the polynuclear metal complex can be stabilized and further enhanced, similar to that of the polynuclear metal complex before modification. The mass loss due to modification is mainly due to the elimination of low-molecular-weight molecules from the polynuclear metal complex or conductive material. This elimination of low-molecular-weight molecules can be confirmed by using a mass spectrometer or similar device to analyze the gaseous components generated during the modification process.

[0176] (carbon content) The modification treatment (e.g., heat treatment, radiation treatment, or electrical discharge treatment) is preferably performed so that the carbon content of the modified metal complex is 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, particularly preferably 30% by mass or more, and most preferably 40% by mass or more. The upper limit of the carbon content is 100% by mass. The higher the carbon content, the more stable the complex structure becomes, and the easier it is to improve the degree of accumulation of metal atoms in the modified metal complex. The carbon content of modified metal complexes can be measured by elemental analysis.

[0177] The distance between the coordinating heteroatoms and metal atoms, as well as the distances between metal atoms in a modified metal complex, can be confirmed using wide-field X-ray absorption fine structure (EXAFS) analysis. Here, heteroatoms refer to oxygen atoms, nitrogen atoms, sulfur atoms, phosphorus atoms, selenium atoms, arsenic atoms, and halogen atoms, more preferably oxygen atoms, nitrogen atoms, sulfur atoms, and phosphorus atoms, even more preferably oxygen atoms, nitrogen atoms, and sulfur atoms, and particularly preferably oxygen atoms and nitrogen atoms. Furthermore, the metal atoms included in the modified metal complex are synonymous with the metal atoms described above. In the EXAFS radial distribution function of the central metal, heteroatoms coordinated to the central metal are observed as peaks originating from the first nearest neighbor atom, and are typically observed in the range of 1.0 Å to 2.5 Å. The lower limit of the range in which the peak originating from the first nearest neighbor atom is observed is more preferably 1.1 Å or higher, and even more preferably 1.2 Å or higher. The upper limit is more preferably 2.2 Å or lower, even more preferably 1.8 Å or lower, and particularly preferably 1.6 Å or lower. Furthermore, the peak originating from the distance between metal atoms in the modified metal complex is observed in the range of 1.8 Å to 2.9 Å. The lower limit of the range in which the peak originating from the distance between metal atoms in the modified metal complex is observed is more preferably 1.9 Å or more, and even more preferably 2.0 Å or more. The upper limit is more preferably 2.8 Å or less, and even more preferably 2.7 Å or less. The peak originating from the distance between metal atoms in the modified metal complex is observed as a separate peak from the peak originating from the metal foil used as a standard, and is observed as a peak with a longer distance between metal atoms.

[0178] <Reacting carbon dioxide with water> The manufacturing method A of the present disclosure comprises reacting carbon dioxide with water in the presence of a modified metal complex obtained from a mixture containing a polynuclear metal complex represented by formula (1) and a conductive material. The reaction is not particularly limited as long as carbon dioxide and water can be reacted in the presence of a modified metal complex obtained from a mixture containing a polynuclear metal complex represented by formula (1) and a conductive material. From the viewpoint of carbon monoxide selectivity, the reaction is preferably carried out using a carbon dioxide reduction apparatus comprising an oxidizing electrode, a carbon dioxide reduction electrode as described later in this disclosure, a membrane separating the oxidizing electrode and the carbon dioxide reduction electrode, an electrolyte, and a power supply connected to the oxidizing electrode and the carbon dioxide reduction electrode. Details of the carbon dioxide reduction electrode and carbon dioxide reduction device will be described later.

[0179] One method for reacting carbon dioxide with water using a carbon dioxide reduction device is to pass an electric current through the oxidation electrode and the carbon dioxide reduction electrode, to flow carbon dioxide into the device so that it comes into contact with the carbon dioxide reduction electrode, and to react the water contained in the electrolyte of the carbon dioxide reduction device with the carbon dioxide on the carbon dioxide reduction electrode.

[0180] ≪Carbon Dioxide Reduction Electrode≫ The carbon dioxide reduction electrode of this disclosure includes a modified metal complex obtained from a mixture containing a polynuclear metal complex represented by the following formula (1) and a conductive material.

[0181] [ka]

[0182] In formula (1), R represents a hydrogen atom or substituent, and any multiple Rs may be the same or different, and two adjacent Rs may be bonded to each other to form a ring structure, and P represents a divalent group containing one or more aromatic rings, Q 1 and Q 2 Q represents a monovalent group containing one or more aromatic rings. 1 and Q 2The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, a is an integer from 2 to 4, and multiple M atoms may be the same or different, X is a counterion or neutral molecule, b is an integer of 0 or more, and if there are multiple X atoms, multiple X atoms may be the same or different, and O is an oxygen atom that is bonded to at least one M atom.

[0183] (Modified metal complex) The preferred embodiment of the modified metal complex in the carbon dioxide reduction electrode of this disclosure is the same as the preferred embodiment of the modified metal complex in manufacturing method A of this disclosure.

[0184] (Support) The carbon dioxide reduction electrode of this disclosure preferably further comprises a support for the modified metal complex. The support is preferably conductive, and examples include carbon nanotubes, graphene, carbon black, carbon cloth, carbon paper, glassy carbon, graphite, and tantalum (Ta).

[0185] (Ionic conductor) The carbon dioxide reduction electrode of this disclosure preferably further comprises an ion conductor. As the ion conductor, any known material can be used and is not particularly limited. An electrolyte solution obtained by dissolving an ionic substance in a solvent such as water may be used, or an ion exchange resin may be used. The ion conductor used between the reducing electrode and the film and the ion conductor used between the oxidizing electrode and the film may be the same or different, and both an electrolyte solution and an ion exchange resin may be used as the ion conductor. Examples of ion conductors include ionomers. An ionomer is a polymer neutralized by ions. Preferably, the ionomer is a polymer neutralized by a cation such as a metal (cationic ionomer) or a polymer neutralized by an anion (anionic ionomer). Examples of anionic ionomers include Sustainion from Dioxide Materials, AEMION from Ionomer Innovations, Fumasep from FumaTech, Orion from Orion, NEOSEPTA from ASTOM, and SELEMION from AGC.

[0186] The ion conductor is preferably 10% to 200% by mass relative to the mass of the conductive material on which the modified metal complex is supported.

[0187] (Other ingredients) The carbon dioxide reduction electrode of this disclosure may include other components besides the modified metal complex, conductive material, support, and ion conductor. Other components include, for example, water-repellent materials. Examples of water-repellent materials include fluorine-containing resins, silicon-containing resins, silane coupling agents, and waxes, but from the viewpoint of water-repellent effect, fluorine-containing resins are preferred, and polytetrafluoroethylene is an example of a fluorine-containing resin.

[0188] (Method for manufacturing carbon dioxide reduction electrodes) The carbon dioxide reduction electrode of this disclosure is preferably manufactured by preparing an electrode ink in which the modified metal complex or a conductive material on which the modified metal complex is supported, an ionic conductor, and other components are dispersed in a solvent, and then applying the electrode ink to a support and drying it.

[0189] (An example of a carbon dioxide reduction electrode) Figure 1 shows an example of a carbon dioxide reduction electrode according to this disclosure. Figure 1 is a schematic cross-sectional view of the carbon dioxide reduction electrode of this disclosure. In Figure 1, the carbon dioxide reduction electrode 10 has a layer 1 on a support 2 that includes a conductive material on which the modified metal complex is supported. If the carbon dioxide reduction electrode contains components other than ion conductors, these components are included in layer 1, which contains the conductive material on which the modified metal complex is supported.

[0190] ≪Carbon Dioxide Reduction Device≫ The carbon dioxide reduction device described herein is Oxidizing electrode and, The carbon dioxide reduction electrode of this disclosure and A membrane separating the oxidizing electrode and the carbon dioxide reduction electrode, Electrolyte and The system comprises a power supply connected to the oxidizing electrode and the carbon dioxide reduction electrode.

[0191] (An example of a carbon dioxide reduction device) Figure 2 shows an example of the carbon dioxide reduction apparatus of this disclosure. In Figure 2, the carbon dioxide reduction device 100 comprises an oxidation electrode 11, a carbon dioxide reduction electrode 10, a membrane 12 separating the oxidation electrode 11 and the carbon dioxide reduction electrode 10, an electrolyte 13, and a power supply 14 connected to the oxidation electrode 11 and the carbon dioxide reduction electrode 10. The carbon dioxide reduction device 100 also includes an electrolytic cell 15 containing these components and a reaction vessel 16. In this case, it is preferable that the carbon dioxide reduction electrode 10 is installed such that the conductive material on which the modified metal complex is supported is in contact with the electrolyte 13.

[0192] The carbon dioxide reduction device 100 is applicable to a reaction that reduces carbon dioxide and produces carbon monoxide. When used in this reaction, it is preferable to use the power supply 14 to pass current from the carbon dioxide reduction electrode 10 towards the oxidation electrode 11. It is also preferable to pass carbon dioxide into the reaction vessel 16 in the direction of arrow A. The carbon dioxide flowing into the reaction vessel 16 comes into contact with the modified metal complex in the carbon dioxide reduction electrode 10. As a result, the reaction represented by reaction equation 1 below proceeds on the carbon dioxide reduction electrode 10 side, and the reaction represented by reaction equation 2 below proceeds on the oxidation electrode 11 side. Reaction equation 1: CO2 + H2O + 2e - →CO+2OH - Reaction equation 2: 2OH - → 1 / 2O2 + H2O + 2e - The generated carbon monoxide then flows out of reaction vessel 16 in the direction of arrow B.

[0193] The carbon dioxide reduction electrode will be described in detail below. Note that symbols will be omitted.

[0194] (Oxidation electrode) As the oxidation electrode, any known type can be used and is not particularly limited, but an electrode that oxidizes water or hydroxide ions to generate oxygen is preferred. Examples include, but are not particularly limited to, metallic materials such as titanium or nickel, or porous materials made of carbonaceous materials such as carbon paper. The oxidation electrode may contain metals such as platinum, palladium, or nickel, or metal oxides such as nickel oxide, iridium oxide, or ruthenium oxide, in order to promote the generation of oxygen.

[0195] (Carbon dioxide reduction electrode) The carbon dioxide reduction electrode is the carbon dioxide reduction electrode described in this disclosure above.

[0196] (film) The membrane separating the carbon dioxide reduction electrode and the oxidation electrode can be any known material, and is not particularly limited, but any material having ion conductivity can be used. For example, porous polymer membranes such as PTFE or porous membranes such as glass filters, cation exchange membranes such as Nafion or FLEMION, or anion exchange membranes such as Sustainion, NEOSEPTA, or SELEMION can be used. While not particularly limited to these, an ion exchange membrane is preferred. Among ion exchange membranes, an anion exchange membrane is more preferred.

[0197] (electrolyte) The electrolyte can be any known type and is not particularly limited, but examples include those containing a cation such as sodium ions or potassium ions, anions such as bicarbonate ions, carbonate ions, hydroxide ions, sulfate ions, phosphate ions, or borate ions, and water.

[0198] The ion concentration of the electrolyte is preferably between 0.01 mol / L and 5.0 mol / L, and more preferably between 0.5 mol / L and 2.0 mol / L.

[0199] (power supply) The power supply is connected to the oxidation electrode and the carbon dioxide reduction electrode. The power source is not particularly limited as long as it is capable of supplying current between the carbon dioxide reduction electrode and the oxidation electrode. For power supply, for example, an electrochemical analyzer 1140D manufactured by BAS Corporation can be used.

[0200] ≪An Embodiment A of Modified Metal Complex≫ One embodiment A of the modified metal complex of the present disclosure is obtained from a mixture containing a polynuclear metal complex represented by the following formula (6).

[0201] [ka]

[0202] In formula (6), R 22 ~R 26 R represents a hydrogen atom or substituent, and there are multiple R 22 ~R 26 These can be the same or different, and the two adjacent Rs 22 Two adjacent Rs 23 Two adjacent Rs 24 Two adjacent Rs 26 R, both adjacent to each other 25 and R 26 The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, and multiple M atoms may be the same or different, X is a counterion or a neutral molecule, b is a non-negative integer, and if there are multiple X atoms, multiple X atoms may be the same or different.

[0203] In one embodiment A of the modified metal complex of the present disclosure, the preferred embodiment of the modified metal complex obtained from a mixture containing a multinuclear metal complex represented by formula (6) is the same as the preferred embodiment of the modified metal complex obtained from a mixture containing a multinuclear metal complex represented by formula (6) in the manufacturing method A of the present disclosure described above.

[0204] In one embodiment A of the modified metal complex of the present disclosure, the mixture preferably further comprises a conductive material. Preferred embodiments of the conductive material are as described above.

[0205] ≪An Embodiment B of a Modified Metal Complex≫ One embodiment B of the modified metal complex of the present disclosure is obtained from a mixture containing a polynuclear metal complex represented by the following formula (10).

[0206] [ka]

[0207] In formula (10), R represents a hydrogen atom or a substituent, and any multiple Rs may be the same or different, and two adjacent Rs may bond to each other to form a ring structure, 3and R 4 R represents a hydrogen atom or substituent, and there are multiple R 3 These can be the same or different, and the two adjacent Rs 3 R adjacent to each other 3 and R 4 They may bond to each other to form a ring structure, Q 1 and Q 2 The formula is as follows (Q a ) or formula (Q b ) represents a monovalent group, M represents a cobalt atom, a nickel atom, or a zinc atom, a is an integer from 2 to 4, and multiple Ms may be the same or different, X is a counterion or neutral molecule, b is an integer of 0 or more, and if there are multiple Xs, multiple Xs may be the same or different, and O is an oxygen atom that is bonded to at least one M.

[0208] [ka]

[0209] Formula (Q a ) and (Q b ), R q R represents a hydrogen atom or substituent, and there are multiple R q These can be the same or different, and the two adjacent Rs q These elements may be bonded to each other to form a ring structure, and * represents a bonding hand.

[0210] A preferred embodiment of the modified metal complex obtained from a mixture containing a polynuclear metal complex represented by formula (10) in one embodiment B of the modified metal complex of the present disclosure is, among the modified metal complex obtained from a mixture containing a polynuclear metal complex represented by formula (1) in the above-described manufacturing method A of the present disclosure, wherein in formula (1), P is of formula (P b It is a divalent group represented by Q 1 and Q 2 is equation (Q a ) or formula (Q b This is the same as the preferred embodiment when representing a monovalent group represented by ).

[0211] In one embodiment B of the modified metal complex of the present disclosure, the mixture preferably further comprises a conductive material. Preferred embodiments of the conductive material are as described above.

[0212] ≪Carbon Monoxide Production Method B≫ The carbon monoxide production method B disclosed herein (hereinafter also referred to as "production method B") is The method involves reacting carbon dioxide with water in the presence of a modified metal complex obtained from a mixture containing a polynuclear metal complex and a conductive material. The aforementioned polynuclear metal complex contains at least one metal atom selected from the group consisting of cobalt atoms, nickel atoms, and zinc atoms, and the distance between the metal atoms, calculated by density functional theory, is less than 3.18 Å.

[0213] A preferred embodiment of manufacturing method B of the present disclosure is identical to a preferred embodiment of manufacturing method A of the present disclosure, except that the polynuclear metal complex contains at least one metal atom selected from the group consisting of cobalt atoms, nickel atoms, and zinc atoms, and the distance between the metal atoms calculated by density functional theory is less than 3.18 Å. In other words, the polynuclear metal complex in manufacturing method B of the present disclosure is not limited to the polynuclear metal complex represented by formula (1) in manufacturing method A of the present disclosure.

[0214] <Distance between metal atoms> In the manufacturing method B of this disclosure, by using a modified metal complex having a binuclear structure with adjacent central metals and a coordination environment to the central metal by macrocyclic ligands, it is presumed that hydrogen generation is suppressed and carbon monoxide production by reduction of carbon dioxide is promoted, resulting in a carbon monoxide manufacturing method with high carbon monoxide selectivity. To improve reduction efficiency, it is thought that increasing the interaction between metal atoms within the coordination environment to the central metal by ligands is effective, and for that purpose, it is presumed that shortening the distance between metal atoms is effective. Here, the manufacturing method B of this disclosure uses a modified metal complex obtained from a multinuclear metal complex in which the distance between metal atoms calculated by density functional theory is less than 3.18 Å. By making the distance between metal atoms calculated by density functional theory in the multinuclear metal complex less than 3.18 Å, the interaction between metal atoms can be greatly increased even in the modified metal complex. Therefore, it is presumed that this will be a method for producing carbon monoxide with high reduction efficiency.

[0215] In the manufacturing method B of the present disclosure, the distance between metal atoms of the polynuclear metal complex, calculated by density functional theory, is less than 3.18 Å, preferably 2.20 Å or more and less than 3.18 Å, more preferably 2.40 Å or more and 3.15 Å or less, even more preferably 2.60 Å or more and 3.13 Å or less, and particularly preferably 2.70 Å or more and 3.10 Å or less. The reason why it is preferable for the distance between metal atoms to be 2.20 Å or greater is that, due to the structure of the multinuclear metal complex, it is difficult to make the distance between metal atoms less than 2.20 Å.

[0216] The distances between metal atoms in a multinuclear metal complex are calculated using a quantum chemistry calculation program. For example, Gaussian16 from Gaussian GmbH can be used as such a program. The structure optimization calculation for the multinuclear metal complex to be used to calculate the distances between metal atoms will be performed using density functional theory (B3LYP / def2svp, sdd for Co, Ni, Zn) to determine the distances between metal atoms. If the SCF (self-consistent field) solution of the structure optimization calculation is an unstable solution, the structure optimization calculation will be performed again to derive a stable solution. Note that the distance between metal atoms refers to the distance between the central metal atoms in a multinuclear metal complex. If a multinuclear metal complex contains three or more central metal atoms in one molecule, the distance between the closest central metal atoms is defined as the distance between metal atoms in manufacturing method B of this disclosure.

[0217] From the viewpoint of carbon monoxide selectivity, the polynuclear metal complex is preferably one in which at least one oxygen atom is coordinately bonded to one metal atom, and more preferably one in which one metal atom and two oxygen atoms are coordinately bonded.

[0218] Furthermore, it is preferable that the manufacturing method A of the present disclosure also satisfies manufacturing method B of the present disclosure. That is, it is preferable that the distance between metal atoms M calculated by density functional theory in manufacturing method A of the present disclosure is less than 3.18 Å. On the other hand, it is also preferable that the manufacturing method B of the present disclosure further satisfies manufacturing method A of the present disclosure. That is, in manufacturing method B of the present disclosure, it is also preferable that the polynuclear metal complex is a polynuclear metal complex represented by formula (1). [Examples]

[0219] The present disclosure will be described in more detail below with reference to examples, but these are illustrative and the present disclosure is not limited thereto. That is, those skilled in the art can implement the present disclosure by making various modifications to the examples shown below. For example, the materials, amounts used, proportions, processing content, processing procedures, etc., shown in the following examples can be modified as appropriate, as long as they do not deviate from the spirit of the present disclosure. The various manufacturing conditions and evaluation result values ​​in the following examples are meant as preferred upper or lower limits in the embodiments of the present disclosure, and the preferred range is meant as a preferred value of the aforementioned upper or lower limit, and the preferred range may be defined by a combination of the aforementioned upper or lower limit value and the values ​​of the following examples or values ​​between examples. In the following description, unless otherwise specified, "parts" and "%" are all based on mass.

[0220] The performance of carbon dioxide reduction electrodes prepared by the method described in the Examples or Comparative Examples was evaluated using the carbon dioxide reduction apparatus 100 shown in Figure 2. A platinum mesh was used as the oxidation electrode 11. A carbon dioxide reduction electrode was used as the reduction electrode 10. An anion exchange membrane (Sustainion, manufactured by Dioxide Materials, Inc.) was used as the membrane 12. A 1.0 M (=1.0 mol / L) potassium hydroxide aqueous solution was used as the electrolyte 13. An electrochemical measuring device (Electrochemical Analyzer 1140D, manufactured by BAS Corporation) was used as the power supply 14. Furthermore, an Hg / HgO reference electrode (manufactured by EC Frontier Co., Ltd.) was placed in the electrolyte 13 between the membrane 12 and the reduction electrode 10 as a reference electrode. Carbon dioxide gas set to 15 mL / min was flowed in the direction of arrow A in the reaction vessel 16, and electrochemical measurements were performed by applying a potential to the reduction electrode 10 using the electrochemical measuring device. Using a gas-tight syringe, 50 μL of the outlet gas (gas flowing out of reaction vessel 16 in the direction of arrow B) was collected, and the products contained in the gas were quantitatively analyzed using a gas chromatograph (GC-2010 / BID detector, Shimadzu Corporation). The current density (mA / cm²) obtained when the potential was applied was measured. 2 A higher value indicates a faster reaction rate. The Faraday efficiency (%) of carbon monoxide (CO) was calculated as the proportion of the charge used to produce the observed carbon monoxide out of the total charge used in the reaction. A higher Faraday efficiency value for carbon monoxide indicates that carbon monoxide is produced selectively, meaning high carbon monoxide selectivity. Partial current density of carbon monoxide (CO) (mA / cm²) 2 The value was calculated using the following formula. A higher value for the partial current density of carbon monoxide indicates that carbon dioxide is being converted to carbon monoxide more efficiently. Partial current density (mA / cm 2 ) = current density (mA / cm 2 ) × Faraday efficiency of carbon monoxide (%) …(B)

[0221] A JEOL JMS S-3000 was used for MALDI-MS measurements.

[0222] A Shimadzu UV-2400PC was used for ultraviolet-visible absorption spectrum measurements.

[0223] (mass reduction rate) The total mass of the multinuclear metal complex and conductive material was measured before and after treatment, and the mass reduction rate was calculated using the following formula (A). Mass reduction rate (%) = [(Total mass of polynuclear metal complex and conductive material before treatment) - (Total amount of polynuclear metal complex and conductive material after treatment) / (Total mass of polynuclear metal complex and conductive material before treatment)] × 100 …(A)

[0224] <Synthesis Example 1> (Synthesis of polynuclear metal complex 1) Using compound 1 synthesized by the method described in Japanese Patent No. 5422159, a polynuclear metal complex 1 was synthesized according to the reaction formula shown below.

[0225] [ka]

[0226] After creating a nitrogen gas atmosphere in the reaction vessel, 7.18 g (28.87 mmol) of nickel acetate tetrahydrate (Ni(OAc)2·4H2O) was suspended in 72.8 g of pre-degassed methanol (MeOH). 148 g of chloroform (CHCl3) was added, and the mixture was heated to 50°C to obtain a nickel acetate solution. In another reaction vessel, after creating a nitrogen gas atmosphere, a suspension was prepared consisting of 8.00 g (11.55 mmol) of compound 1 and 180 g of chloroform. This suspension was added dropwise to the above nickel acetate solution, and the mixture was heated to 55°C and stirred under reflux for 1 hour to obtain a reaction solution containing polynuclear metal complex 1. After cooling the reaction solution to room temperature, it was filtered. The obtained crystals were washed with methanol and dried under reduced pressure to obtain polynuclear metal complex 1 in a yield of 8.60 g and 93%. The identification data for the obtained polynuclear metal complex 1 is shown below. The results of MALDI-MS measurements were confirmed as follows. MALDI-MS[M-OAc] + :m / z=807.2

[0227] The interatomic distances in polynuclear metal complex 1 were 2.92 Å.

[0228] <Synthesis Example 2> (Synthesis of Compound 2) Compound 2 was synthesized using compound 1, which was synthesized by the method described in Japanese Patent No. 5422159, according to the reaction formula shown below.

[0229] [ka]

[0230] After creating a nitrogen gas atmosphere in the reaction vessel, 10.00 g (14.43 mmol) of compound 1 was added to 370 g of chloroform (CHCl3) and suspended, then the temperature was raised to 50°C. In another reaction vessel, after creating a nitrogen gas atmosphere, a suspension consisting of 2.65 g (14.43 mmol) of zinc acetate (Zn(OAc)2) and 90 g of methanol (MeOH) was prepared. The zinc acetate suspension was added dropwise to the suspension of compound 1, and the temperature was raised to 55°C, and the mixture was stirred under reflux for 1 hour to obtain a reaction solution containing compound 2. After cooling this reaction solution to room temperature, water was added and the mixture was stirred for a while to wash and remove the aqueous phase. Heptane was added to the obtained organic phase and concentrated, then filtered. Compound 2 was obtained in a yield of 10.9 g and 100% by drying the obtained crystals under reduced pressure. The identification data for the obtained compound 2 is shown below. The results of MALDI-MS measurement were confirmed as follows. MALDI-MS[M+H] + :m / z=756.23

[0231] <Synthesis Example 3> (Synthesis of polynuclear metal complex 2) The polynuclear metal complex 2 was synthesized according to the reaction equation shown below.

[0232] [ka]

[0233] After creating a nitrogen gas atmosphere in the reaction vessel, 2.00 g (2.65 mmol) of compound 2 was added to 200 g of chloroform (CHCl3) and suspended, then the temperature was raised to 50°C. In another reaction vessel, after creating a nitrogen gas atmosphere, a suspension consisting of 0.66 g (2.65 mmol) of nickel acetate tetrahydrate (Ni(OAc)2·4H2O) and 40 g of methanol (MeOH) was prepared. The nickel acetate suspension was added dropwise to the suspension of compound 2, and the temperature was raised to 55°C and stirred under reflux for 1.5 hours to obtain a reaction solution containing polynuclear metal complex 2. After cooling this reaction solution to room temperature, it was filtered. The obtained crystals were washed with methanol and dried under reduced pressure to obtain polynuclear metal complex 2 in a yield of 1.91 g and 83%. The identification data for the obtained polynuclear metal complex 2 is shown below. The results of MALDI-MS measurement were confirmed as follows. MALDI-MS[M-OAc] + :m / z=813.9

[0234] The interatomic distances in polynuclear metal complex 2 were 2.90 Å.

[0235] <Synthesis Example 4> (Synthesis of polynuclear metal complex 3) A polynuclear metal complex 3 was synthesized using compound 3 synthesized by the method described in Japanese Patent No. 5422159, according to the reaction formula shown below.

[0236] [ka]

[0237] After creating a nitrogen gas atmosphere in the reaction vessel, 0.74 g (1.19 mmol) of nickel acetate tetrahydrate was suspended in 12 g of pre-degassed methanol (MeOH). 44 g of chloroform (CHCl3) was added, and the mixture was heated to 50°C to obtain a nickel acetate solution. In another reaction vessel, after creating a nitrogen gas atmosphere, a suspension was prepared consisting of 0.87 g (2.97 mmol) of compound 3 and 44 mL of chloroform. This suspension was added dropwise to the above nickel acetate solution, and the mixture was heated to 55°C and stirred under reflux for 1 hour to obtain a reaction solution containing polynuclear metal complex 3. After cooling the reaction solution to room temperature, it was filtered. The obtained crystals were washed with methanol and dried under reduced pressure to obtain polynuclear metal complex 3 in a yield of 0.85 g and 85%. The identification data for the obtained polynuclear metal complex 3 is shown below. The results of MALDI-MS measurements were confirmed as follows. MALDI-MS[M+H] + :m / z=847.3

[0238] The interatomic distances in polynuclear metal complex 3 were 3.05 Å.

[0239] <Synthesis Example 5> (Synthesis of polynuclear metal complex 4) The polynuclear metal complex 4 was synthesized according to the reaction equation shown below.

[0240] [ka]

[0241] After creating a nitrogen gas atmosphere in the reaction vessel, 1.49 g (6.00 mmol) of nickel acetate tetrahydrate was added to 10 mL of methanol (MeOH) and suspended. To this nickel acetate suspension, 4 mL of methanol solution containing 0.65 g (6.00 mmol) of 1,2-phenylenediamine was added with stirring and the temperature was raised to reflux. Subsequently, 42 mL of methanol solution containing 0.90 g (6.00 mmol) of 2,6-diformylphenol was gradually added, and reflux was carried out for 3 hours. After concentrating the solution with an evaporator, it was cooled to room temperature and filtered. The obtained crystals were washed with acetone and dried under reduced pressure to obtain polynuclear metal complex 4 in a yield of 1.52 g and 75%. The identification data for the obtained polynuclear metal complex 4 is shown below. The results of MALDI-MS measurement were confirmed as follows. MALDI-MS[M] + :m / z=558.0

[0242] The interatomic distances in polynuclear metal complex 4 were 2.83 Å.

[0243] <Synthesis Example 6> (Synthesis of polynuclear metal complex 5) Using compound 4 synthesized by the method described in Tetrahedron, 1999, 55, 8377, the polynuclear metal complex 5 was synthesized according to the reaction formula shown below.

[0244] [ka]

[0245] After creating a nitrogen gas atmosphere in the reaction vessel, 1.75 g (7.04 mmol) of nickel acetate tetrahydrate was suspended in 10 mL of methanol (MeOH) and 5 mL of chloroform (CHCl3). To this nickel acetate suspension, 101 mL of chloroform solution containing 1.50 g (2.82 mmol) of compound 4 was added while stirring, and the temperature was raised to reflux. Subsequently, 10 mL of chloroform solution containing 0.30 g (2.82 mmol) of 1,2-phenylenediamine was gradually added, and reflux was carried out for 3 hours. After concentrating the solution with an evaporator, acetone was added, and the mixture was cooled to room temperature and filtered. The obtained crystals were washed with acetone and dried under reduced pressure to obtain polynuclear metal complex 5 in a yield of 1.68 g and 71%. The identification data for the obtained polynuclear metal complex 5 is shown below. The results of MALDI-MS measurement were confirmed as follows. MALDI-MS[M] + :m / z=718.14

[0246] The interatomic distances in polynuclear metal complex 5 were 2.79 Å.

[0247] <Synthesis Example 7> (Synthesis of polynuclear metal complex 6) A polynuclear metal complex 6 was synthesized using compound 5 synthesized by the method described in Japanese Patent No. 5396031, according to the reaction formula shown below.

[0248] [ka]

[0249] After creating a nitrogen gas atmosphere in the reaction vessel, 0.90 g (3.63 mmol) of nickel acetate tetrahydrate was added to 15 g of pre-degassed methanol (MeOH), and the temperature was raised to 55°C to obtain a nickel acetate solution. In another reaction vessel, after creating a nitrogen gas atmosphere, a suspension consisting of 1.00 g (1.65 mmol) of compound 5 and 20 g of chloroform (CHCl3) was prepared. This suspension was added dropwise to the above nickel acetate solution, and the mixture was stirred under reflux for 1 hour to obtain a reaction solution containing the polynuclear metal complex 6. After cooling this reaction solution to room temperature, it was filtered. The obtained crystals were washed with methanol to obtain the polynuclear metal complex 6 in a yield of 0.35 g and 25%. The identification data for the obtained polynuclear metal complex 6 is shown below. The results of MALDI-MS measurement were confirmed as follows. MALDI-MS[M-OAc] + :m / z=720.15

[0250] The interatomic distances in polynuclear metal complex 6 were 2.98 Å.

[0251] <Synthesis Example 8> (For comparison: Synthesis of polynuclear metal complex 7) According to the method described in J.Phys.Chem.B 2005, 109, 2836, the polynuclear metal complex 7 was synthesized according to the reaction equation shown below.

[0252] [ka]

[0253] After creating a nitrogen gas atmosphere in the reaction vessel, 0.45 g (1.10 mmol) of tris(2-benzimidazolylmethyl)amine was added to 9 g of pre-degassed ethanol, and the mixture was heated to 78°C to dissolve. In another reaction vessel, after creating a nitrogen gas atmosphere, 0.24 g (1.10 mmol) of nickel bromide was added to 9 g of pre-degassed ethanol and dissolved. This nickel bromide solution was added dropwise to the above tris(2-benzimidazolylmethyl)amine solution, and the mixture was stirred under reflux for 5 hours to obtain a reaction solution containing polynuclear metal complex 7. After concentrating this reaction solution, it was cooled to room temperature and filtered to obtain polynuclear metal complex 9 in a yield of 0.64 g and 93%. The identification data for the obtained polynuclear metal complex 7 is shown below. The results of the ultraviolet-visible absorption spectrum measurement were confirmed as follows. The methanol solution of polynuclear metal complex 7 had peak wavelengths at 394 nm and 632 nm.

[0254] The interatomic distances in the polynuclear metal complex 7 were 3.18 Å.

[0255] <Synthesis Example 9> (Synthesis of polynuclear metal complex 8) The polynuclear metal complex 8 was synthesized according to the reaction equation shown below.

[0256] [ka]

[0257] After creating a nitrogen gas atmosphere in the reaction vessel, 2.00 g (2.65 mmol) of compound 2 was added to 200 g of chloroform (CHCl3) and suspended, then the temperature was raised to 50°C. In another reaction vessel, after creating a nitrogen gas atmosphere, a suspension consisting of 0.66 g (2.65 mmol) of cobalt acetate tetrahydrate (Co(OAc)2·4H2O) and 40 g of methanol (MeOH) was prepared. The nickel acetate suspension was added dropwise to the suspension of compound 2, and the temperature was raised to 55°C and stirred under reflux for 2 hours to obtain a reaction solution containing polynuclear metal complex 8. After cooling this reaction solution to room temperature, 40 g of methanol containing 0.27 g (2.65 mmol) of triethylamine was added and the mixture was filtered. The obtained crystals were washed with methanol and dried under reduced pressure to obtain polynuclear metal complex 8 in a yield of 1.55 g and 67%. The identification data for the obtained polynuclear metal complex 8 is shown below. The results of MALDI-MS measurement were confirmed as follows. MALDI-MS[M-OAc] + :m / z=812.1

[0258] The interatomic distances in the polynuclear metal complex 8 were 2.93 Å.

[0259] <Synthesis Example 10> (Synthesis of polynuclear metal complex 9) A polynuclear metal complex 9 was synthesized according to the method described in Japanese Patent No. 5422159, following the reaction equation shown below.

[0260] [ka]

[0261] After creating a nitrogen gas atmosphere in the reaction vessel, a suspension consisting of 5.00 g (6.82 mmol) of compound 3 and 45 g of chloroform was prepared. In another reaction vessel, after creating a nitrogen gas atmosphere, 15 g of pre-degassed methanol was added to 4.25 g (17.05 mmol) of cobalt acetate tetrahydrate to prepare a cobalt acetate solution. This cobalt acetate solution was added dropwise to the above compound 3 suspension, and the mixture was heated to 55°C and stirred under reflux for 3 hours to obtain a reaction solution containing the polynuclear metal complex 9. After cooling the reaction solution to room temperature, it was filtered. The obtained crystals were washed with methanol and water to obtain the polynuclear metal complex 9 in a yield of 5.07 g and 88%. The identification data for the obtained polynuclear metal complex 9 is shown below. The results of MALDI-MS measurement were confirmed as follows. MALDI-MS[M] + :m / z=846.1

[0262] The interatomic distances in the polynuclear metal complex 9 were 2.96 Å.

[0263] <Mononuclear metal complexes> For comparison, I purchased the following mononuclear metal complexes.

[0264] [ka]

[0265] Nickel(II) tetraphenylporphyrin (Ni(TPP)) was purchased from Sigma-Aldrich.

[0266] [ka]

[0267] Nickel(II) phthalocyanine (Ni(Pc)) was purchased from Sigma-Aldrich.

[0268] Nickel(II) acetate tetrahydrate (Ni(OAc)2) was purchased from Tokyo Chemical Industry Co., Ltd.

[0269] [ka]

[0270] Cobalt(II) tetraphenylporphyrin (Co(TPP)) was purchased from Tokyo Chemical Industries.

[0271] [ka]

[0272] Cobalt(II) phthalocyanine (Co(Pc)) was purchased from Tokyo Chemical Industry Co., Ltd.

[0273] <Examples 1-16 and Comparative Examples 1-20> (Preparation of mixtures 1 to 14) One g of carbon black (KetjenBlack EC600JD, manufactured by Lion Specialty Chemicals, Inc.) was weighed into a reaction vessel as the conductive material. A metal complex was weighed into another reaction vessel so that the mass of metal atoms was 5% by mass relative to the carbon black. After adding a solvent and confirming that a solution of the metal complex had been formed, the solution was transferred to the reaction vessel containing the weighed conductive material to form a dispersion. By irradiating this dispersion with ultrasound, a suspension was obtained in which the conductive material supported by the metal complex was uniformly dispersed. After obtaining a wet cake (WC) of the mixture by filtration of the suspension using a filter or concentration to dryness using an evaporator, the mixture was dried under reduced pressure at 80°C to obtain mixtures 1 to 14 containing the conductive material supported by the metal complex. Table 1 shows the metal complex, solvent, and WC acquisition method used to prepare mixtures 1 to 14.

[0274] [Table 1]

[0275] -TGA measurement- The change in mass (TGA) of the mixture during heat treatment was measured using a thermal mass / differential thermal analyzer (Bruker TG-DTA 2010SA). The measurement was performed under the same conditions as when preparing the modified metal complex. A sample consisting of the above mixture was placed in a platinum dish and heated under a nitrogen atmosphere with a heating rate of 10°C / min, followed by heating at 60°C for 1 hour, then at 300°C for 1 hour, and finally at the highest temperature reached for 1 hour.

[0276] (Modification treatment of the mixture: Preparation of modified metal complexes 1A-14A and 1B-14B) Based on the findings from the TGA measurement results described above, the metal complexes were subjected to a modification treatment (heat treatment) of the mixture so that the mass loss rate during the heat treatment of the mixture was 1% to 15% by mass. The heat treatment was carried out using a tubular furnace (Isuzu Manufacturing Co., Ltd. program-controlled open / closed tubular furnace EPKRO-14R) under a nitrogen atmosphere, with a program of 60°C for 1 hour, followed by 300°C for 1 hour, and then at the maximum temperature reached for 1 hour. Table 3 shows the mixtures used to prepare modified metal complexes 1A to 14A and modified metal complexes 1B to 14B, the metal complexes contained in each mixture, the maximum temperature reached during the heat treatment, the mass loss rate after the heat treatment, and the resulting modified metal complexes.

[0277] (Fabrication of carbon dioxide reduction electrodes (1) to (16) and (1') to (20')) To a screw tube, 20.0 mg of the aforementioned mixture or a modified metal complex powder obtained from the aforementioned mixture, 2.50 mL of ethanol, and 100 mg of a 5% solution of Nafion (manufactured by WAKO Corporation) as a cationic ionomer acting as an ion conductor were added to obtain a dispersion. This dispersion was irradiated with ultrasound to obtain an ink. Using carbon paper (25 mm in diameter) as a support, 250 mg of the obtained ink was applied to the carbon paper and then dried to obtain carbon dioxide reduction electrodes (1) to (16) and (1') to (20'), respectively. The mixtures or modified metal complexes used to prepare the carbon dioxide reduction electrodes in Examples 1 to 16 and Comparative Examples 1 to 20 are shown in Tables 2 and 3.

[0278] (Evaluation results of carbon dioxide reduction efficiency) Electrochemical measurements were performed using the carbon dioxide reduction electrodes obtained in Examples 1-16 and Comparative Examples 1-20, according to the method described above. The results are shown in Tables 2 and 3.

[0279] [Table 2]

[0280] [Table 3]

[0281] -Comparison of multinuclear and mononuclear metal complexes- Tables 2 and 3 show that when modified metal complexes using multinuclear metal complexes were used (Examples 1-16), the partial current density of carbon monoxide was higher than when modified metal complexes using mononuclear metal complexes (Comparative Examples 9-14 and 17-20), indicating more efficient conversion of carbon dioxide to carbon monoxide.

[0282] -Comparison of the mixture before heat treatment and the modified metal complex obtained after heat treatment- Tables 2 and 3 show that when the modified metal complex obtained by heat treatment was used (Examples 1-16), the partial current density of carbon monoxide was higher than when the mixture before heat treatment was used (Comparative Examples 1-6 and 15-16), indicating efficient conversion of carbon dioxide to carbon monoxide.

[0283] -Comparison based on distance between metal atoms- Tables 2 and 3 show that when multinuclear metal complexes with interatomic distances of less than 3.18 Å were used (Examples 1-12), the partial current density of carbon monoxide was higher than when multinuclear metal complexes with interatomic distances of 3.18 Å or more were used (Comparative Examples 7-8), indicating more efficient conversion of carbon dioxide to carbon monoxide.

[0284] From the above results, it can be seen that manufacturing methods A and B of this disclosure showed higher partial current densities of carbon monoxide and higher reduction efficiency of carbon dioxide to carbon monoxide compared to the comparative example. [Explanation of Symbols]

[0285] 1: Layer containing a conductive material on which a modified metal complex is supported; 2: Support; 10: Carbon dioxide reduction electrode; 11: Oxidation electrode; 12: Film; 13: Electrolyte; 14: Power supply; 15: Electrolytic cell; 16: Reaction vessel; 100: Carbon dioxide reduction device

Claims

1. A method for producing carbon monoxide, comprising reacting carbon dioxide with water in the presence of a modified metal complex obtained from a mixture containing a polynuclear metal complex represented by the following formula (1) and a conductive material. 【Chemistry 1】 (In formula (1), R represents a hydrogen atom or substituent, and any multiple Rs may be the same or different, and two adjacent Rs may be bonded to each other to form a ring structure, and P represents a divalent group containing one or more aromatic rings, Q １ and Q ２ Q represents a monovalent group containing one or more aromatic rings. １ and Q ２ The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, a is an integer from 2 to 4, and multiple M atoms may be the same or different, X is a counterion or neutral molecule, b is an integer of 0 or more, and if there are multiple X atoms, multiple X atoms may be the same or different, and O is an oxygen atom that bonds to at least one M atom.

2. The method for producing carbon monoxide according to claim 1, wherein the modified metal complex is obtained by heat treatment, radiation treatment, or electrical discharge treatment of the mixture.

3. The method for producing carbon monoxide according to claim 2, wherein the heat treatment, radiation treatment, or discharge treatment is performed such that the mass reduction rate calculated by the following formula (A) is between 1% and 90%. Mass reduction rate (%) = [(Total mass of polynuclear metal complex and conductive material before treatment) - (Total mass of polynuclear metal complex and conductive material after treatment) / (Total mass of polynuclear metal complex and conductive material before treatment)] × 100 … (A)

4. In the above formula (1), P is given by the following formula (P ａ ), formula (P ｂ ), or formula (P ｃ A method for producing carbon monoxide according to claim 1 or claim 2, wherein the divalent group is represented by ). 【Chemistry 2】 (In formula (P ａ ), R １ and R ２ represent a hydrogen atom or a substituent, and a plurality of R １ and R ２ may be the same or different from each other, and two adjacent R １ to each other and two adjacent R ２ to each other may combine with each other to form a ring structure.) Formula (P ｂ ) Medium, R ３ and R ４ R represents a hydrogen atom or substituent, and there are multiple R ３ These can be the same or different, and the two adjacent Rs ３ R adjacent to each other ３ and R ４ These elements may bond to each other to form a ring structure. Formula (P ｃ ) Medium, R ５ R represents a hydrogen atom or substituent, and there are multiple R ５ These can be the same or different, and Y is given by the following formula (P ｃ１ ), formula (P ｃ２ ), or formula (P ｃ３ ) represents a Y, and the multiple Ys may be the same or different, and Z represents an alkylene group or an arylene group. Formula (P ａ ) ~ formula (P ｃ (In the above, * represents a combination.) 【Transformation 3】 (Formula (P ｃ１ ) ~ formula (P ｃ３ ) Medium, R ｐ (where * represents a hydrogen atom or substituent, and * represents a bond.)

5. The method for producing carbon monoxide according to claim 1 or claim 2, wherein the polynuclear metal complex is a compound represented by the following formula (2). 【Chemistry 4】 (In formula (2), R ６ ~R ８ R represents a hydrogen atom or substituent, and there are multiple R ６ ~R ８ These can be the same or different, and the two adjacent Rs ６ Two adjacent Rs ７ Two Rs that are adjacent to each other ８ They may bond to each other to form a ring structure, Q ３ and Q ４ Q represents a monovalent group containing one or more aromatic rings. ３ and Q ４ The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, a is an integer from 2 to 4, and multiple M atoms may be the same or different, X is a counterion or neutral molecule, b is an integer of 0 or more, and if there are multiple X atoms, multiple X atoms may be the same or different, and O is an oxygen atom that bonds to at least one M atom.

6. In the above formula (1), P is given by the following formula (P ａ ) or formula (P ｂ It is a divalent group represented by Q １ and Q ２ The formula is as follows (Q ａ ) or formula (Q ｂ A method for producing carbon monoxide according to claim 1 or claim 2, wherein the monovalent group is represented by ). 【Transformation 5】 (Formula (P ａ ) Medium, R １ and R ２ R represents a hydrogen atom or substituent, and there are multiple R １ and R ２ These can be the same or different, and the two adjacent Rs １ Two Rs that are adjacent to each other ２ These elements may bond to each other to form a ring structure. Formula (P ｂ ) Medium, R ３ and R ４ R represents a hydrogen atom or substituent, and there are multiple R ３ These can be the same or different, and the two adjacent Rs ３ R adjacent to each other ３ and R ４ These elements may bond to each other to form a ring structure. Formula (P ａ ) and formula (P ｂ (In the above, * represents a combination.) 【Transformation 6】 (Formula (Q ａ ) and (Q ｂ ) Medium, R ｑ R represents a hydrogen atom or substituent, and there are multiple R ｑ These can be the same or different, and the two adjacent Rs ｑ These elements may bond to each other to form a ring structure, and * represents a bonding hand.

7. The method for producing carbon monoxide according to claim 1 or claim 2, wherein the polynuclear metal complex is a compound represented by the following formula (3). 【Transformation 7】 (In formula (3), R ９ ~R １３ R represents a hydrogen atom, substituent, or divalent group, and there are multiple R ９ ~R １２ These can be the same or different, and the two adjacent Rs ９ Two adjacent Rs １０ Two adjacent Rs １１ Two adjacent Rs １２ R, both adjacent to each other １２ and R １３ They may bond to each other to form a ring structure, R １３ If is a divalent group, the divalent group may combine with other compounds represented by formula (3) to form a dimer, where M represents a cobalt atom, a nickel atom, or a zinc atom, and multiple Ms may be the same or different, where X is a counterion or a neutral molecule, where b is an integer of 0 or more, and if there are multiple Xs, multiple Xs may be the same or different.

8. The method for producing carbon monoxide according to claim 1 or claim 2, wherein the polynuclear metal complex is a compound represented by the following formula (4). 【Transformation 8】 (In formula (4), R １４ ~R １６ R represents a hydrogen atom or substituent, and there are multiple R １４ ~R １６ These can be the same or different, and the two adjacent Rs １４ Two adjacent Rs １５ R, both adjacent to each other １５ and R １６ The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, and multiple M atoms may be the same or different, X is a counterion or neutral molecule, b is a non-negative integer, and if there are multiple X atoms, each X atom may be the same or different.

9. The method for producing carbon monoxide according to claim 1 or claim 2, wherein the polynuclear metal complex is a compound represented by the following formula (5). 【Chemistry 9】 (In formula (5), R １７ ~R ２１ represents a hydrogen atom or a substituent, and a plurality of R １７ ~R ２１ may be the same or different from each other, and two adjacent R １７ s, two adjacent R １８ s, two adjacent R １９ s, two adjacent R ２０ s, and two adjacent R ２１ s may combine with each other to form a ring structure. M represents a cobalt atom, a nickel atom, or a zinc atom. X is a counter ion or a neutral molecule, b is an integer of 0 or more, and when there are a plurality of Xs, the plurality of Xs may be the same or different from each other.)

10. The method for producing carbon monoxide according to claim 1 or claim 2, wherein the polynuclear metal complex is a compound represented by the following formula (6). 【Chemistry 10】 (In formula (6), R ２２ ~R ２６ R represents a hydrogen atom or substituent, and there are multiple R ２２ ~R ２６ These can be the same or different, and the two adjacent Rs ２２ Two adjacent Rs ２３ Two adjacent Rs ２４ Two adjacent Rs ２６ R, both adjacent to each other ２５ and R ２６ The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, and multiple M atoms may be the same or different, X is a counterion or neutral molecule, b is a non-negative integer, and if there are multiple X atoms, each X atom may be the same or different.

11. The method for producing carbon monoxide according to claim 1 or claim 2, wherein the polynuclear metal complex is a compound represented by the following formula (7). 【Chemistry 11】 (In formula (7), R ２７ ~R ３４ R represents a hydrogen atom or substituent, and there are multiple R ２７ ~R ３４ These can be the same or different, and the two adjacent Rs ２７ Two adjacent Rs ２８ Two adjacent Rs ２９ Two adjacent Rs ３０ Two adjacent Rs ３１ Two adjacent Rs ３２ Two adjacent Rs ３３ Two Rs that are adjacent to each other ３４ The elements may bond to each other to form a ring structure; Ar represents a divalent aromatic group which may have substituents; M represents a cobalt atom, a nickel atom, or a zinc atom; a is an integer from 2 to 4, and multiple Ms may be the same or different; X is a counterion or a neutral molecule; b is an integer of 0 or more, and if there are multiple Xs, multiple Xs may be the same or different; O is an oxygen atom which is bonded to at least one M.

12. The method for producing carbon monoxide according to claim 1 or claim 2, wherein the polynuclear metal complex is a compound represented by the following formula (8). 【Chemistry 12】 (In formula (8), Z represents an alkylene group or an arylene group, and the multiple Zs may be the same or different, R ３５ R represents a hydrogen atom or substituent, and there are multiple R ３５ These can be the same or different, and the two adjacent Rs ３５ They may bond to each other to form a ring structure, and Y is given by the following formula (P ｃ１ ), formula (P ｃ２ ), or formula (P ｃ３ ) represents a cobalt atom, nickel atom, or zinc atom, and multiple Ys may be the same or different. X is a counterion or neutral molecule, and b is a non-negative integer. If there are multiple Xs, they may be the same or different. 【Chemistry 13】 (Formula (P ｃ１ ) ~ formula (P ｃ３ ) Medium, R ｐ (where * represents a hydrogen atom or substituent, and * represents a bond.)

13. A carbon dioxide reduction electrode comprising a modified metal complex obtained from a mixture containing a polynuclear metal complex represented by the following formula (1) and a conductive material. 【Chemistry 14】 (In formula (1), R represents a hydrogen atom or substituent, and any multiple Rs may be the same or different, and two adjacent Rs may be bonded to each other to form a ring structure, and P represents a divalent group containing one or more aromatic rings, Q １ and Q ２ Q represents a monovalent group containing one or more aromatic rings. １ and Q ２ The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, a is an integer from 2 to 4, and multiple M atoms may be the same or different, X is a counterion or neutral molecule, b is an integer of 0 or more, and if there are multiple X atoms, multiple X atoms may be the same or different, and O is an oxygen atom that bonds to at least one M atom.

14. The carbon dioxide reduction electrode according to claim 13, further comprising a support for the modified metal complex.

15. The carbon dioxide reduction electrode according to claim 14, further comprising an ion conductor.

16. Oxidizing electrode and, A carbon dioxide reduction electrode according to any one of claims 13 to 15, A membrane separating the oxidizing electrode and the carbon dioxide reduction electrode, Electrolyte and The system comprises a power supply connected to the oxidizing electrode and the carbon dioxide reduction electrode, Carbon dioxide reduction device.

17. A modified metal complex obtained from a mixture containing a polynuclear metal complex represented by the following formula (6). 【Chemistry 15】 (In formula (6), R ２２ ~R ２６ R represents a hydrogen atom or substituent, and there are multiple R ２２ ~R ２６ These can be the same or different, and the two adjacent Rs ２２ Two adjacent Rs ２３ Two adjacent Rs ２４ Two adjacent Rs ２６ R, both adjacent to each other ２５ and R ２６ The atoms may bond to each other to form a ring structure, M represents a cobalt atom, a nickel atom, or a zinc atom, and multiple M atoms may be the same or different, X is a counterion or neutral molecule, b is a non-negative integer, and if there are multiple X atoms, each X atom may be the same or different.

18. The modified metal complex according to claim 17, wherein the mixture further comprises a conductive material.

19. A modified metal complex obtained from a mixture containing a polynuclear metal complex represented by the following formula (10). 【Chemistry 16】 (In formula (10), R represents a hydrogen atom or a substituent, and any multiple Rs may be the same or different, and two adjacent Rs may be bonded to each other to form a ring structure, R ３ and R ４ R represents a hydrogen atom or substituent, and there are multiple R ３ These can be the same or different, and the two adjacent Rs ３ R adjacent to each other ３ and R ４ They may bond to each other to form a ring structure, Q １ and Q ２ The formula is as follows (Q ａ ) or formula (Q ｂ ) represents a monovalent group, where M represents a cobalt atom, nickel atom, or zinc atom, a is an integer from 2 to 4, and multiple Ms may be the same or different, X is a counterion or neutral molecule, b is an integer of 0 or more, and if there are multiple Xs, each X may be the same or different, and O is an oxygen atom that is bonded to at least one M. 【Chemistry 17】 (Formula (Q ａ ) and (Q ｂ ) Medium, R ｑ R represents a hydrogen atom or substituent, and there are multiple R ｑ These can be the same or different, and the two adjacent Rs ｑ These elements may bond to each other to form a ring structure, and * represents a bonding hand.

20. The modified metal complex according to claim 19, wherein the mixture further comprises a conductive material.

21. The method involves reacting carbon dioxide with water in the presence of a modified metal complex obtained from a mixture containing a polynuclear metal complex and a conductive material. The aforementioned polynuclear metal complex contains at least one metal atom selected from the group consisting of cobalt atoms, nickel atoms, and zinc atoms, and the distance between the metal atoms calculated by density functional theory is less than 3.18 Å. A method for producing carbon monoxide.

22. The method for producing carbon monoxide according to claim 21, wherein the polynuclear metal complex is a polynuclear metal complex in which one metal atom and two oxygen atoms are coordinately bonded.

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