CN115894494A - Ligands, complexes and their applications in electrochemical reactions - Google Patents

Abstract

The application discloses ligands, complexes and applications in electrochemical reactions. In the first aspect of the present application, a ligand is provided, and the structural formula of the ligand is shown in Formula I. In existing phthalocyanines and porphyrins, the N atom that coordinates with the metal is pyrrole nitrogen, and after coordination, two protons are removed to obtain a negatively charged ligand, making the complex as a whole electrically neutral. There are four pyridine nitrogens in the ligand, and the cationic complex obtained after coordination has better catalytic performance than the existing phthalocyanine or porphyrin catalysts. Moreover, the ligand is a ring-closed rigid structure ligand formed by four pyridine groups, and the single bond between two adjacent pyridine groups cannot be rotated and has a unique conformation. When the ligand is used to form a complex with a metal, the aromatic ring structures of the complex are located on the same plane, which endows the complex with stronger stability and catalytic activity.

Description

Ligands, complexes and their applications in electrochemical reactions

technical field

The application relates to the technical field of complexes, in particular to ligands, complexes and their application in electrochemical reactions.

Background technique

Renewable energy conversion is an important method to develop clean energy and solve environmental problems. Carbon dioxide electrolyzers and fuel cells are two different types of devices in the field of renewable energy conversion, and they have attracted much attention for their high efficiency and green features. Among them, the strategy adopted by the carbon dioxide electrolyzer is electrocatalytic carbon dioxide reduction (CO ₂ RR) technology, which reduces atmospheric CO ₂ into useful compounds (such as CO, CH ₄ , C ₂ H ₄ , C ₂ H ₅ OH, etc.), this technology converts electrical energy into chemical energy, which can not only reduce the content of carbon dioxide in the atmosphere, but also realize the storage of electrical energy. The focus of this technology is how to develop catalysts with superior performance and low cost to achieve efficient conversion of electrical energy. The fuel cell mainly converts the chemical energy of the anode fuel into electrical energy through an electrochemical process, while the oxygen reduction reaction (ORR) at the cathode directly affects the conversion efficiency of the fuel cell. At present, commercial catalysts are mainly platinum-based catalysts, but the use of noble metal platinum leads to high cost of fuel cell catalysts. Therefore, the development of ORR catalysts with low cost and higher catalytic efficiency is also a research hotspot in fuel cell technology.

Metal complexes have been extensively studied in electrochemical reactions, especially carbon dioxide reduction reaction (CO ₂ RR) and oxygen reduction reaction (ORR), among which MNC materials are considered to be the most promising non-precious metal catalysts. It is generally believed that the active center of this type of catalyst is MN ₄ formed by the coordination of metal M and four nitrogen atoms, and its catalytic activity is affected by various factors such as transition metal source and nitrogen source. As an important participant in the catalytic active center, the nitrogen source is mainly in the form of a nitrogen-containing ligand containing a pyrrole structure. At present, phthalocyanine and porphyrin are mainly used, and their bodies and various derivatives have been commercialized. The N atom that coordinates with the metal in these two types of structures is pyrrole nitrogen. When four coordination is formed, two protons are removed to form a negatively charged ligand, and it coordinates with the metal cation to form an electrically neutral complex. However, there is no report on the catalytic activity of electrically neutral tetrapyridine ligands and their metal-nitrogen (M-N4) complexes in electrochemical reactions such as CO ₂ RR and ORR.

Contents of the invention

This application aims to solve at least one of the technical problems existing in the prior art. For this reason, this application proposes a ligand, a complex and its application in electrochemical reactions. The ligand is an electrically neutral ligand, and a cationic complex can be obtained by using the ligand and a metal ion. In CO ₂ RR and good catalytic activity in ORR.

In the first aspect of the present application, a ligand is provided, and the structural formula of the ligand is shown in Formula I:

Wherein, R ¹ , R ² , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are independently selected from hydrogen atom, halogen atom, carbonyl group, hydroxyl group, carboxyl group, aldehyde group, nitro group, amino group, pyrazinyl group, C _{1- 30} alkyl, C _1-30 alkylamino, C 3-30 cycloalkyl, C _1-30 alkoxy, C _3-30 cycloalkyloxy _, C _6-40 aryl, C _6-40 aryl Baseoxy group, C _6-40 arylamino group, and adjacent groups in R ¹ , R ² , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ can be connected to each other to form a ring.

The ligand according to the embodiment of the present application has at least the following beneficial effects:

In existing phthalocyanines and porphyrins, the N atom that coordinates with the metal is pyrrole nitrogen, and after coordination, two protons are removed to obtain a negatively charged ligand, so that the complex as a whole is electrically neutral. There are four pyridine nitrogens in the ligand, and the cationic complex obtained after the coordination has better catalytic performance than the existing phthalocyanine or porphyrin catalysts. Moreover, the ligand is a ligand with a closed ring rigid structure formed by four pyridine groups, and the single bond between two adjacent pyridine groups cannot be rotated and has a unique conformation. When the ligand is used to form a complex with a metal, the aromatic ring structures of the complex are located on the same plane, which endows the complex with stronger stability and catalytic activity.

Specifically, with reference to Fig. 1, a, b and c respectively show the electronic structure of a kind of existing phthalocyanine, a kind of porphyrin and a kind of ligand in the embodiment of the present application and metal ion coordination, Among them, the N atom where the phthalocyanine or porphyrin coordinates with the metal is pyrrole nitrogen, so after coordination, two protons will be removed to obtain a negatively charged ligand, and the complex as a whole is electrically neutral; In contrast, the N used for coordination in the ligand claimed by the application represented by c is all pyridinic nitrogen, which will not be deprotonated after peve, so that an electrically neutral ligand is formed, and the obtained cationic complexes.

Wherein, R ¹ and R ² are the same substituent, or, R ¹ and R ² are different substituents. When R ¹ and R ² are the same substituent, R ¹ and R ² are selected from hydrogen atom, halogen atom, carbonyl, hydroxyl, aldehyde, carboxyl, nitro, amino, pyrazinyl, C _1-30 alkyl , C _1-30 alkylamino, C _3-30 cycloalkyl, C _1-30 alkoxy, C _3-30 cycloalkyloxy, C _6-40 aryl, C _6-40 aryloxy , the same substituent in C _6-40 arylamino; when R ¹ and R ² are different substituents, R ¹ and R ² are selected from hydrogen atom, halogen atom, carbonyl, hydroxyl, aldehyde, carboxyl, Nitro, amino, pyrazinyl, C _1-30 alkyl, C _1-30 alkylamino, C _3-30 cycloalkyl, C _1-30 alkoxy, C _3-30 cycloalkyloxy, Different substituents in C _6-40 aryl, C _6-40 aryloxy, and C _6-40 arylamino.

Similarly, R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are the same group, or R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are different groups. When R ¹ and R ² are the same group, R ¹ and R ² are selected from hydrogen atom, halogen atom, carbonyl, hydroxyl, aldehyde, carboxyl, nitro, amino, pyrazinyl, C _1-30 alkyl , C _1-30 alkylamino, C _3-30 cycloalkyl, C _1-30 alkoxy, C _3-30 cycloalkyloxy, C _6-40 aryl, C _6-40 aryloxy , the same substituent in C _6-40 arylamino; when R ¹ and R ² are different substituents, R ¹ and R ² are selected from hydrogen atom, halogen atom, carbonyl, hydroxyl, aldehyde, carboxyl, Nitro, amino, pyrazinyl, C _1-30 alkyl, C _1-30 alkylamino, C _3-30 cycloalkyl, C _1-30 alkoxy, C _3-30 cycloalkyloxy, Different substituents in C _6-40 aryl, C _6-40 aryloxy, and C _6-40 arylamino.

In some embodiments of the present application, R ¹ and R ² are independently selected from hydrogen atom, halogen atom, carbonyl, hydroxyl, aldehyde, nitro, carboxyl, amino, pyrazinyl, C _1-20 alkyl, C ₁ -C ₂₀ alkylamino, C _1-20 alkoxy, C _3-20 cycloalkyl, C _3-20 cycloalkyloxy, C _6-30 aryl, C _6-30 aryloxy, C _6-30 arylamino.

In some embodiments of the present application, R ¹ and R ² are independently selected from hydrogen atom, halogen atom, carbonyl, hydroxyl, aldehyde, nitro, carboxyl, amino, pyrazinyl, C _1-10 alkyl, C ₁ -C ₁₀ alkylamino, C _1-10 alkoxy, C _3-10 cycloalkyl, C _3-10 cycloalkyloxy, C _6-20 aryl, C _6-20 aryloxy, C _6-20 arylamino.

In some embodiments of the present application, R ¹ and R ² are independently selected from hydrogen atom, halogen atom, carbonyl, hydroxyl, nitro, carboxyl, amino, pyrazinyl, C _1-10 alkyl, C ₁ -C ₁₀ alkylamino, C _1-10 alkoxy, C _3-10 cycloalkyl, C _3-10 cycloalkyloxy, C _6-10 aryl, C _6-10 aryloxy, C _{6- 10} Arylamino.

In some embodiments of the present application, R ¹ and R ² are independently selected from hydrogen atom, halogen atom, carbonyl, hydroxyl, nitro, carboxyl, amino, pyrazinyl, C _1-8 alkyl, C ₁ -C ₈ alkylamino, C _1-8 alkoxy, C _3-8 cycloalkyl, C _3-8 cycloalkyloxy, C _6-8 aryl, C _6-8 aryloxy, C _{6- 8} arylamino.

In some embodiments of the present application, R ¹ and R ² are independently selected from hydrogen atom, halogen atom, carbonyl, hydroxyl, nitro, carboxyl, amino, pyrazinyl, C _1-6 alkyl, C ₁ -C ₆ alkylamino, C _1-6 alkoxy, C _3-6 cycloalkyl, C _3-6 cycloalkyloxy, phenyl, phenyloxy, phenylamino.

In some embodiments of the present application, R ¹ and R ² are independently selected from a hydrogen atom, a halogen atom, a methyl group, an ethyl group, a carbonyl group, an aldehyde group, a carboxyl group, and an amino group.

In some embodiments of the present application, R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are independently selected from a hydrogen atom, a halogen atom, a carbonyl group, a hydroxyl group, an aldehyde group, a nitro group, a carboxyl group, an amino group, a pyrazinyl group, a C _{1 -20} alkyl, C ₁ -C ₂₀ alkylamino, C _1-20 alkoxy, C _3-20 cycloalkyl, C _3-20 cycloalkyloxy, C _6-30 aryl, C _{6- 30} aryloxy, C _6-30 arylamino.

In some embodiments of the present application, R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are independently selected from a hydrogen atom, a halogen atom, a carbonyl group, a hydroxyl group, an aldehyde group, a nitro group, a carboxyl group, an amino group, a pyrazinyl group, a C _{1 -10} alkyl, C ₁ -C ₁₀ alkylamino, C _1-10 alkoxy, C _3-10 cycloalkyl, C _3-10 cycloalkyloxy, C _6-20 aryl, C _{6- 20} aryloxy, C _6-20 arylamino.

In some embodiments of the present application, R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are independently selected from hydrogen atom, halogen atom, carbonyl, hydroxyl, nitro, carboxyl, amino, pyrazinyl, C _1-10 alkane radical, C ₁ -C ₁₀ alkylamino, C _1-10 alkoxy, C _3-10 cycloalkyl, C _3-10 cycloalkyloxy, C _6-10 aryl, C _6-10 aryl Oxygen, C _6-10 arylamino.

In some embodiments of the present application, R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are independently selected from hydrogen atom, halogen atom, carbonyl, hydroxyl, nitro, carboxyl, amino, pyrazinyl, C _1-8 alkane base, C ₁ -C ₈ alkylamino, C _1-8 alkoxy, C _3-8 cycloalkyl, C _3-8 cycloalkyloxy, C _6-8 aryl, C _6-8 aryl Oxygen, C _6-8 arylamino.

In some embodiments of the present application, R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are independently selected from hydrogen atom, halogen atom, carbonyl, hydroxyl, nitro, carboxyl, amino, pyrazinyl, C _1-6 alkane radical, C ₁ -C ₆ alkylamino, C _1-6 alkoxy, C _3-6 cycloalkyl, C _3-6 cycloalkyloxy, phenyl, phenyloxy, phenylamino.

In some embodiments of the present application, R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are each independently selected from a hydrogen atom, a halogen atom, a methyl group, an ethyl group, a carbonyl group, an aldehyde group, a carboxyl group, and an amino group.

In some embodiments of the present application, R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are all hydrogen atoms.

In some embodiments of the present application, the halogen atom is selected from at least one of fluorine, chlorine, bromine, and iodine.

In some embodiments of the present application, R ¹ and R ² may be connected to each other to form a ring, and/or R ⁸ and R ⁹ may be connected to each other to form a ring, and/or R ¹⁰ and R ¹¹ may be connected to each other to form a ring. In some of these embodiments, R ¹ and R ² can be connected to each other to form a five-membered ring or a six-membered ring, and/or R ⁸ and R ⁹ can be connected to each other to form a five-membered ring or a six-membered ring, and/or, R ¹⁰ and R ¹¹ can be connected to each other to form a five-membered ring or a six-membered ring. In some of these embodiments, the five-membered ring or six-membered ring is independently selected from any one of carbocycles and heteroatom-containing carbocycles. In some of these embodiments, the heteroatom-containing carbocycle is a carbocycle containing at least one heteroatom optionally selected from boron, nitrogen, oxygen, and sulfur atoms. In some of these embodiments, the heteroatom-containing carbocycle is a carbocycle containing at least two heteroatoms selected from boron, nitrogen, oxygen, and sulfur atoms. In some of these embodiments, R ¹ and R ² may be connected to each other to form a dioxolane.

In some embodiments of the present application, R ¹ and R ² are independently selected from a hydrogen atom, a halogen atom, a methyl group, an ethyl group, a carbonyl group, and an amino group, or R ¹ and R ² are connected to each other to form a dioxolane.

In some embodiments of the present application, R ¹ and R ² are both hydrogen atoms, or halogen atoms, or methyl groups, or ethyl groups, or carbonyl groups, or amino groups, or R ¹ and R ² are connected to each other to form dioxolane .

In some embodiments of the present application, R ¹ and R ² are simultaneously a hydrogen atom, or a halogen atom, or a methyl group, or an ethyl group, or a carbonyl group, or an amino group, or R ¹ and R ² are connected to each other to form a 1,3- dioxolane.

In some embodiments of the present application, R ¹ and R ² are simultaneously a hydrogen atom, or a halogen atom, or a methyl group, or an ethyl group, or a carbonyl group, or an amino group, or R ¹ and R ² are connected to each other to form a 2,2- Dimethyl-1,3-dioxolane.

The second aspect of the present application provides a preparation method of a ligand, the preparation method comprising the following steps:

S1: Compound Ⅲ is reacted with compound Ⅳ to obtain compound Ⅴ;

S2: compound V reacts with compound IX to obtain compound VI;

S3: compound VI is oxidized to obtain compound VII;

S4: compound VII is deprotected to obtain compound VIII;

S5: compound VIII reacts with compound X to obtain a ligand represented by formula I;

Wherein, R ³ and R ⁴ are independently selected from halogen atom, alkyl tin, boron group;

R ⁵ and R ⁶ are independently selected from boronic acid groups and halogen atoms;

R ⁷ is C _1-30 alkyl;

Z is an amino protecting group.

In some embodiments of the present application, Z is any one of Boc, Fmoc, and Cbz.

In some embodiments of the present application, R ^{and R} are independently selected from halogen atoms (including but not limited to chlorine atoms, bromine atoms), alkyl tin (including but not limited to butyl tin, methyl tin), boron ( Including but not limited to any of boronic acid group, boric acid pinacol ester).

In some embodiments of the present application, R ⁵ and R ⁶ are each independently selected from any one of a boronic acid group, a chlorine atom, and a bromine atom.

In some embodiments of the present application, Compound V is obtained through Suzuki or Stille coupling reaction between Compound III and Compound IV in S1.

In some embodiments of the present application, compound V and compound IX in S2 are reacted to obtain compound VI through Suzuki or Stille coupling reaction.

In some embodiments of the present application, the catalyst in S1 and/or S2 is a palladium catalyst.

In some embodiments of the present application, the catalyst in S1 and/or S2 is selected from tetrakis(triphenylphosphine)palladium, bis(triphenylphosphine)palladium dichloride, 1,1'-bis(diphenylphosphine) ) at least one of ferrocenepalladium dichloride, bis(dibenzylideneacetone)palladium, tris(dibenzylideneacetone)dipalladium, and bis(tricyclohexylphosphine)palladium dichloride.

In some embodiments of the present application, the temperature of the coupling reaction in S1 and/or S2 is 60-150°C. The reaction temperature is favorable for the coupling reaction to proceed.

In some embodiments of the present application, the oxidizing agent in S3 is selenium dioxide.

In some embodiments of the present application, the reaction temperature in S3 is 60-100°C.

In some embodiments of the present application, the reaction solvent in S3 is dioxane.

In some embodiments of the present application, the protecting group is Boc, and the deprotection reaction in S4 is under acidic conditions. In some embodiments, the acidic condition in S4 is provided by at least one acid selected from hydrochloric acid, p-toluenesulfonic acid, trifluoroacetic acid, and aluminum trichloride. In some of these embodiments, the acid in S4 is dissolved in any solvent of dichloromethane, ethyl acetate and water to provide acidic conditions. In some of the embodiments, the volume ratio of the acid and the solvent in S4 is 1:(1-4). In some embodiments, the acid in S4 is trifluoroacetic acid, the solvent is dichloromethane, and the volume ratio of the acid to the solvent is 1: (1-4). In some embodiments, the volume ratio of trifluoroacetic acid and dichloromethane in S4 is about 1:2.

In some embodiments of the present application, compound VIII and compound X in S5 react at room temperature to obtain the ligand represented by formula I. In some of these embodiments, the reaction solvent is methanol.

In the third aspect of the present application, a complex is provided. The structural formula of the complex is shown in formula II:

Wherein, M is a metal cation, X is an anion, and n is the ratio of the valence state of M to the valence state of X.

In some embodiments of the present application, M is a cation of a transition metal element.

In some embodiments of the present application, M is a cation of any metal element in the 4th to 6th periods, from groups IB to VIIB and group VIII.

In some embodiments of the present application, M is scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium , Lutetium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, mercury in any metal cation.

In some embodiments of the present application, M is selected from cations of any metal element in iron, cobalt, nickel, copper, manganese, ruthenium, platinum, chromium, and zinc.

In some embodiments of the present application, X is a halide ion, a carboxylate ion, a sulfate ion, a sulfite ion, a hydroxide ion, a nitrate ion, a phosphate ion, a monohydrogen phosphate ion, a dihydrogen phosphate ion ions, carbonate ions, bicarbonate ions, chlorate ions, perchlorate ions, iodate ions, and periodate ions.

In some embodiments of the present application, X is at least one of fluoride ion, chloride ion, bromide ion, iodide ion, formate ion, acetate ion, phosphate ion, sulfate ion, and perchlorate ion.

In some embodiments of the present application, n can be an integer or a decimal depending on the valence states of M and X.

In a fourth aspect of the present application, a method for preparing the aforementioned complex is provided, the preparation method comprising the following steps:

Take the aforementioned ligand or the ligand prepared according to the aforementioned complex preparation method;

The ligand and MX _n are complexed in a solvent to form a complex shown in formula II.

In some embodiments of the present application, the solvent is at least one of an organic solvent or water.

In some embodiments of the present application, the organic solvent is at least one selected from methanol, ethanol, N,N-dimethylformamide, dimethyl sulfoxide, and dichloromethane.

In some embodiments of the present application, the temperature of the complexation reaction between the ligand and MX _n is 20-60°C.

In a fifth aspect of the present application, a catalyst is provided, which comprises the aforementioned complex.

In some embodiments of the present application, the catalyst includes a carrier and a complex immobilized on the carrier. In some of these embodiments, the support is a carbon support. In some embodiments, the carrier includes at least one of carbon nanotubes, graphene, and carbon black.

In some embodiments of the present application, the catalyst is a composite catalyst, and the composite catalyst includes the aforementioned complexes and other metal or non-metal catalysts. In some of these embodiments, the metal catalysts include simple metals (such as nanomaterials of Cu, Co, Sn, Au, In, Pb, Ag, Zn, etc.), metal organic framework materials (such as Ni-MOF, NiFe-MOF, etc.) . In some of these embodiments, the non-metallic catalyst includes a carbon material.

According to the sixth aspect of the present application, an electrode or electrolyte solution is provided, and the electrode or electrolyte solution includes the aforementioned complex or the aforementioned catalyst.

In some embodiments of the present application, the electrode includes a conductive carrier and a catalyst layer formed on the conductive carrier, and the raw material of the catalyst layer includes the aforementioned catalyst or complex. In some embodiments, the conductive carrier is selected from at least one of carbon cloth, carbon paper, glassy carbon, carbon nanotubes, and graphite. In some embodiments, the raw material of the catalyst layer further includes at least one of a binder and an additive. In some embodiments, the binder and the additive are selected from at least one of perfluorosulfonic acid polymer (Nafion), polyvinylpyrrolidone, and polyvinylpyridine. It can be understood that, in some embodiments, the catalyst layer of the electrode may not contain binders and additives, and/or, the electrode does not contain a conductive carrier but only contains a catalyst layer.

In some embodiments of the present application, the electrolyte is an acidic, neutral or alkaline electrolyte. In some of the embodiments, the acid in the acidic electrolyte to adjust the acidity of the electrolyte may be sulfuric acid, perchloric acid or hydrochloric acid of appropriate concentration. The alkali for adjusting the alkalinity of the electrolyte in the alkaline electrolyte can be sodium hydroxide, potassium hydroxide or lithium hydroxide of appropriate concentration.

In some embodiments of the present application, any one of other inorganic salts, organic salts, and catalysts may also be included in the electrolyte. In some of these embodiments, the solvent of the electrolyte is at least one of an inorganic solvent or an organic solvent, wherein the inorganic solvent can be water, and the organic solvent can be acetonitrile, N,N-dimethylformamide, tetrahydrofuran, dimethylformamide At least one of the group sulfoxides. In some embodiments, organic salts or inorganic salts can be added to the electrolyte to increase conductivity, including but not limited to at least one of bicarbonate, sulfate, perchlorate, and tetrabutylammonium hexafluorophosphate.

According to the seventh aspect of the present application, a device is provided, which includes the aforementioned complex, or the aforementioned catalyst, or the aforementioned electrode or electrolyte.

In some embodiments of the present application, the device is selected from any one of a fuel cell and a carbon dioxide electrolyzer.

In some embodiments of the present application, a device includes a cathode, an anode, and an electrolyte. The electrolyte or cathode includes the aforementioned complexes, catalysts, and the like.

In some embodiments of the present application, a fuel cell includes an anode, an oxygen reducing cathode, and an electrolyte positioned between the anode and the oxygen reducing cathode. In some of these embodiments, the electrolyte can be a solid electrolyte or a liquid electrolyte. In some embodiments, the oxygen reduction cathode includes the aforementioned catalyst or complex; in other embodiments, the electrolyte includes the aforementioned catalyst or complex.

In some embodiments of the present application, a carbon dioxide electrolyzer includes an anode, a cathode, and an electrolyte. In some of these embodiments, the electrolyte can be a solid electrolyte or a liquid electrolyte. In some embodiments, the aforementioned catalyst or complex is included on the cathode; in other embodiments, the aforementioned catalyst or complex is included in the electrolyte.

The eighth aspect of the present application provides a gas reduction method, the method comprising mixing the aforementioned complex or the aforementioned catalyst with a gas to electrocatalytically reduce the gas; the gas is selected from any one of carbon dioxide and oxygen.

In some embodiments of the present application, a carbon dioxide reduction method is provided, the method comprising mixing the aforementioned complex or the aforementioned catalyst with carbon dioxide and water, and electrocatalytically reducing carbon dioxide.

In some embodiments of the present application, a method for reducing oxygen is provided, the method comprising mixing the aforementioned complex or catalyst with oxygen and hydrogen, and electrocatalytically reducing oxygen.

In some embodiments of the present application, the electrochemical reaction is any one of carbon dioxide reduction reaction and oxygen reduction reaction.

In some embodiments of the present application, the carbon dioxide reduction reaction includes a reaction in which carbon dioxide is reduced to form a product.

In some embodiments of the present application, the carbon dioxide reduction product includes at least one of a one-carbon compound, a two-carbon compound, and a three-carbon compound. In some embodiments, the one-carbon compound includes at least one of carbon monoxide, formic acid, methanol, and methane. In some embodiments of the present application, the two-carbon compound includes at least one of ethylene, ethanol, ethylene glycol, acetic acid, and oxalic acid. In some embodiments of the present application, the three-carbon compound includes at least one of propylene, n-propanol, propionaldehyde, and acetone.

In some embodiments of the present application, the carbon dioxide reduction reaction includes the reduction of carbon dioxide to generate carbon monoxide.

In some embodiments of the present application, the oxygen reduction reaction includes the reaction of reducing oxygen to generate hydrogen peroxide.

In the examples of this application, an electrically neutral tetrapyridine ligand was synthesized and prepared as a metal-nitrogen (MN ₄ ) complex, which is effective in the electrocatalytic carbon dioxide reduction reaction (CO ₂ RR) and oxygen reduction Reaction (ORR) showed excellent catalytic activity. The ligand is a closed-ring rigid structure, the pyridine groups cannot be rotated, and the conformation is single; while the N4 aromatic ring structure of the complex formed by the ligand and the metal ion is in the same plane, and its comparison is verified by electrochemical catalytic reaction. Based on the existing non-planar aromatic ring structure, it has good catalytic activity and stability.

On the other hand, the complex formed by the electrically neutral ligand and the metal cation is a cationic complex, which is essentially different from the existing porphyrin and phthalocyanine complexes, and no cationic ligand has been reported yet. The catalytic performance of neutral ligands and anionic ligands is a cutting-edge scientific issue, and it is also one of the topics currently being explored in the field of electrocatalysis. The neutral ligands provided in the examples of the present application are superior to the anionic ligands in performance, indicating that such neutral ligands have great prospects.

Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application.

Description of drawings

Fig. 1 is the different electronic structures when the ligand (c) provided in the examples of the present application is coordinated with the existing phthalocyanine (a), porphyrin (b) and metal ions.

Figure 2 is the result of the electrocatalytic carbon dioxide reduction reaction catalytic activity experiment in Example 11 of the present application, wherein a is the partial current density j _co of the complex 1-12 and Co(II) CPY as the catalyst when the product is CO, b is the Faradaic efficiency (FE) distribution.

Fig. 3 is the result of the oxygen reduction reaction catalytic activity experiment in the embodiment 12 of the present application, a is the current density of the linear sweep voltammetry (LSV) of the experimental group and the control group, b is the experimental group H ₂ O ₂ productive rate and The number of electrons transferred is n.

Detailed ways

The idea and technical effects of the present application will be clearly and completely described below in conjunction with the embodiments, so as to fully understand the purpose, features and effects of the present application. Apparently, the described embodiments are only some of the embodiments of the present application, not all of them. Based on the embodiments of the present application, other embodiments obtained by those skilled in the art without creative efforts belong to The protection scope of this application.

The following describes the embodiments of the present application in detail, and the described embodiments are exemplary and are only used for explaining the present application, and should not be construed as limiting the present application.

In the description of the present application, several means more than one, and multiple means more than two. Greater than, less than, exceeding, etc. are understood as not including the original number, and above, below, within, etc. are understood as including the original number. If the description of the first and second is only for the purpose of distinguishing the technical features, it cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features relation. In the following description, although a logical order is shown in the flowcharts, in some cases, the steps shown or described may be performed in an order different from that in the flowcharts.

Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application, and are not intended to limit the present application.

In the description of this application, reference to the terms "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific examples," or "some examples" is intended to mean that the embodiments Specific features, structures, materials, or characteristics described in or examples are included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The experimental methods used in the following examples are conventional methods unless otherwise specified.

The concentrations in the following examples are molar concentrations unless otherwise specified.

Materials, reagents, etc. used in the following examples can all be obtained from commercial sources, and the specific information is as follows:

2-Aminophenylboronic acid: 97%, Anaiji Chemical;

Di-tert-butyl dicarbonate: 98%, Anaiji Chemical;

Triethylamine: AR, Anaiji Chemical;

4-Dimethylaminopyridine: AR, Biide Pharmaceuticals;

Dichloromethane: AR, Greagent;

Petroleum ether: AR, Greagent;

Ethyl acetate: AR, Greagent;

Anhydrous sodium sulfate: AR, Greagent;

Deuterated chloroform: 99.6% D, Anaiji Chemical;

8-Bromo-2-methylquinoline: 97%, Bi De Pharmaceutical;

n-Butyllithium: 1.6M hexane solution, Anaiji Chemical;

Trimethyl borate: 98%, Anaiji chemical;

Ultra-dry tetrahydrofuran: AR, Anaiji Chemical;

Anhydrous ether: AR, Greagent;

Anhydrous methanol: AR, Greagent;

2,9-dichloro-1,10-phenanthroline: AR, Bi De Pharmaceutical;

Tetrakistriphenylphosphine palladium: AR, Anaiji Chemical;

Ultra-dry 1,4-dioxane: AR, Anaiji Chemical;

Selenium dioxide: AR, McLean Biochemical;

Ultra-dry dichloromethane: AR, Anaiji Chemical;

Trifluoroacetic acid: AR, Anaiji Chemical;

Vinyl n-butyl ether: 98%, Anaiji Chemical;

Potassium carbonate anhydrous: AR, McLean Biochemical;

Deuterated methanol: 99.8% D, Anaiji Chemical;

Deuterated dimethyl sulfoxide: 99.9% D, Anaiji chemical;

Cobalt acetate tetrahydrate: AR, McLean Biochemical;

Anhydrous ferric chloride: AR, McLean Biochemical;

Nickel acetate tetrahydrate: AR, McLean Biochem.

Compounds in the following examples were characterized by nuclear magnetic resonance (Brucker ARX-400) or high-resolution mass spectrometry (ESI).

The synthetic route of complex in the following examples is carried out according to the following reaction equation:

Embodiment 1, the preparation of compound 1-2

Under argon atmosphere, after dissolving 2-aminophenylboronic acid (2g, 14.6mmol, compound 1-1) in 25mL of dichloromethane, di-tert-butyl dicarbonate (3.5g, 16.1mmol) was added at zero degrees Celsius, three Ethylamine (2.2g, 21.9mmol) and 4-dimethylaminopyridine (178mg, 0.15mmol), then rose to room temperature, after reacting overnight, the reaction solution was concentrated to obtain a crude product, which was purified on a silica gel column (petroleum ether: ethyl acetate Ester=10:1 (V/V)), and the white hair (1.18g) was obtained, which was compound 1-2, and the yield was 34%.

NMR results of compound 1-2: ¹ H NMR (400MHz, CDCl ₃ ) δ9.41(s, 1H), 7.81(d, J=7.4Hz, 1H), 7.67(d, J=8.3Hz, 1H), 7.31–7.21(m,1H),7.08–6.95(m,1H),1.39(s,9H). ¹³ C NMR(100MHz,CDCl ₃ )δ154.75,142.63,134.96,133.72,131.13,123.05,116.61,82.97, 28.48.

Embodiment 2, the preparation of compound 1-4

Under argon atmosphere, 8-bromo-2-methylquinoline (1g, 4.5mmol, compound 1-3) was dissolved in 15mL ultra-dry tetrahydrofuran, then the system was placed in a dry ice acetone bath, and slowly added dropwise to the solution 1.6M n-BuLi (6.2 mL, 9.9 mmol). After the addition of n-butyllithium was complete, the reaction mixture was allowed to react completely for 45 minutes. Then, trimethyl borate (1.2 g, 11.3 mmol) was added dropwise to the system, and reacted for 1 hour after the addition was complete. Then it was raised to room temperature, and after the reaction was continued for 2 hours, 10 mL of ultrapure water was added to the system to quench the reaction. Then 20 mL of 3M hydrochloric acid solution was added, and stirred at room temperature for 0.5 hours. The tetrahydrofuran in the reaction mixture was removed by a rotary evaporator, the resulting reaction mixture was washed with 15 mL of anhydrous ether, and the aqueous phase was basified with potassium carbonate to adjust the pH to close to 10. At this time, a precipitate was precipitated. After filtration, the obtained solid was washed with water, and finally washed with a very small amount of methanol to obtain a light yellow solid (0.54 g), which was compound 1-4, with a yield of 65%.

NMR results of compound 1-4: ¹ H NMR (400MHz, Chloroform-d) δ8.85(s, 2H), 8.44–8.34(m, 1H), 8.15(d, J=8.4Hz, 1H), 7.95– 7.87(m,1H),7.64–7.53(m,1H),7.41–7.26(m,1H),2.79(s,3H). ¹³ C NMR(100MHz,CDCl ₃ )δ157.70,151.75,137.86,137.60,130.47 ,125.93,121.60,25.16.

Embodiment 3, the preparation of compound 1-6

Add 2,9-dichlorophenanthroline (0.5g, 2mmol, compound 1-5), compound 1-2 (521mg, 2.2mmol), potassium carbonate (415mg, 3mmol) into the high-temperature internal pressure tube, and then add 8 milliliters of dioxane and 4 milliliters of ultra-clean water, after passing through argon for 20 minutes to get rid of the air in the solution, add tetrakis triphenylphosphine palladium (116mg, 0.05mol%), heat to 120 degrees centigrade reaction after sealing 2 hours, then waited to cool to room temperature, added 6 ml of water, extracted three times with dichloromethane, collected the organic phase, dried with anhydrous sodium sulfate, concentrated the filtrate after filtration, and then carried out the crude product to silica gel column purification (petroleum ether: Ethyl acetate=1:3 (V/V)), a light yellow solid (382 mg) was obtained, which was compound 1-6, and the yield was 47%.

NMR results of compound 1-6: ¹ H NMR (400MHz, CDCl ₃ ) δ11.92(s, 1H), 8.41–8.33(m, 1H), 8.17(d, J=8.5Hz, 1H), 8.07(d ,J=8.4Hz,1H),7.88(d,J=8.6Hz,1H),7.70–7.58(m,3H),7.52(d,J=8.4Hz,1H),7.38–7.29(m,1H) ,7.04–6.95(m,1H),1.44(s,9H). ¹³ C NMR(101MHz,CDCl ₃ )δ158.33,153.98,151.33,145.58,143.11,138.96,138.64,137.29,130.38,129.46,127.54,12 126.41, 125.84, 125.71, 124.40, 122.97, 122.15, 121.11, 79.77, 28.43.

Embodiment 4, the preparation of compound 1-7

Add compound 1-6 (382mg, 0.94mmol), compound 1-4 (193mg, 1.1mmol), potassium carbonate (195mg, 1.4mmol) into the high-temperature pressure-resistant tube, then add 8 ml of dioxane and 4 ml Ultra-clean water, after being fed with argon for 20 minutes, add tetrakis triphenylphosphine palladium (54mg, 0.05mol%), seal and heat to 120 degrees Celsius to react for 2 hours, then wait to cool to room temperature, add 6 milliliters of water, use After dichloromethane was extracted three times, the organic phase was collected, dried with anhydrous sodium sulfate, and the filtrate was concentrated after filtration, and then the crude product was subjected to silica gel column purification (petroleum ether: ethyl acetate=1:1 (V/V)), to obtain Yellow foamy solid (337 mg), namely compound 1-7, yield 70%.

NMR results of compound 1-7: ¹ H NMR (400MHz, CDCl ₃ ) δ12.16(s, 1H), 9.17–9.10(m, 1H), 9.03(d, J=8.4Hz, 1H), 8.37(d ,J=8.3Hz,1H),8.34–8.24(m,2H),8.14(d,J=8.4Hz,1H),7.98–7.91(m,2H),7.84–7.71(m,4H),7.51– 7.43(m, 1H), 7.33(d, J=8.4Hz, 1H), 7.21–7.12(m, 1H), 2.78(s, 3H), 1.23(s, 9H). ¹³ C NMR (100MHz, CDCl ₃ )δ158.68,157.63,157.24,154.17,145.69,145.43,144.60,138.48,137.33,136.65,134.53,133.27,129.85,129.48,129.21,127.86,127.67,127.57,126.83,126.59,126.57,126.13,125.49,122.57,122.30 ,122.19,121.64,79.58,28.12,25.69.

Embodiment 5, the preparation of compound 1-8

Under argon atmosphere, compound 1-7 (300mg, 0.59mmol) was dissolved in 15m dioxane, selenium dioxide (130mg, 1.17mmol) was added, then raised to 80 degrees Celsius, reacted for 3 hours, and concentrated the reaction solution to obtain The crude product was purified on a silica gel column (petroleum ether: ethyl acetate = 1:3 (V/V)) to obtain a light red foamy solid (264 mg), which was compound 1-8, with a yield of 85% .

NMR data of compound 1-8: ¹ H NMR (400MHz, Chloroform-d) δ12.01(s, 1H), 10.14(s, 1H), 9.15(d, J=7.1Hz, 1H), 8.87(d, J＝8.4Hz, 1H), 8.41–8.27(m, 3H), 8.25–8.18(m, 1H), 8.04–7.87(m, 4H), 7.84(d, J＝8.7Hz, 1H), 7.78(d , J＝8.7Hz, 1H), 7.71–7.64(m, 1H), 7.41–7.32(m, 1H), 7.13–7.06(m, 1H), 1.11(s, 9H). ¹³ C NMR (100MHz, CDCl ₃ )δ193.84,152.27,145.73,138.40,138.07,137.45,134.83,134.32,130.33,129.95,129.82,129.52,129.24,128.07,127.52,126.75,126.54,126.03,122.65,122.25,117.10,79.60,28.10.

Embodiment 6, the preparation of compound 1-9

Compound 1-8 (200 mg, 0.38 mmol) was dissolved in 8 mL of dichloromethane, then 4 mL of trifluoroacetic acid was added, and reacted overnight at room temperature, the reaction solution was concentrated to obtain a tan crude product, which was redissolved in 5 mL of methanol and stirred for 2 hours. After methanol was removed by evaporation under reduced pressure, the crude product was washed with ethyl acetate and dichloromethane to obtain a red solid (110 mg), which was compound 1-9, with a yield of 66%.

NMR data of compound 1-9: ¹ H NMR (500MHz, Methanol-d ₄ ) δ8.90(d, J=7.2Hz, 1H), 8.82(d, J=8.6Hz, 1H), 8.77(d, J =8.7Hz,1H),8.54(d,J=8.2Hz,1H),8.34(d,J=7.6Hz,1H),8.19(s,2H),7.96–7.84(m,4H),7.69(d ,J=8.3Hz,1H),7.47–7.39(m,1H),7.11(d,J=8.2Hz,1H),6.96(m,1H),5.98(s,1H),3.35(s,3H) . ¹³ C NMR(125MHz,MeOH-d4)δ159.17,158.02,151.33,145.36,145.19,144.01,140.76,137.24,136.11,135.84,134.66,133.86,132.40,129.77,129.22,129.13,128.38,127.79,127.58,124.50 ,123.27,121.52,120.80,118.46,116.96,114.29,81.54.

Embodiment 7, the preparation of compound 1-11

Dissolve compound 1-9 (110 mg, 0.25 mmol) in 6 mL of methanol, add 3 mL of vinyl butyl ether, react overnight at room temperature, concentrate the reaction solution, redissolve in 5 mL of methanol, add 2 mL of 2M hydrochloric acid and stir for 2 hours , directly spin-dried to obtain the crude product, which was washed with ethyl acetate and dichloromethane to obtain the ligand hydrochloride (91 mg) with a yield of 78%. Preparative chromatography gave a more pure product, but in somewhat reduced yield. The obtained ligand hydrochloride was dissolved in methanol and basified with potassium carbonate to obtain ligand compound 1-11.

NMR data of compound 1-11: ¹ H NMR (500MHz, DMSO-d ₆ ) δ8.26 (d, J=8.4Hz, 2H), 8.21–8.14 (m, 4H), 8.11–8.01 (m, 4H) ,7.83(d,J＝8.0Hz,2H),7.79(s,2H),7.63–7.54(m,2H). ¹³ CNMR(125MHz,DMSO-d ₆ )δ155.25,154.67,144.89,144.34,139.01,136.71 ,132.35,132.24,130.91,127.90,127.07,126.43,126.16,122.69,119.37.

HRMS (ESI) Theoretical C ₃₀ H ₁₇ N ₄ ⁺ [M+H] ⁺ : 433.1448; Found: 433.1450.

Embodiment 8, the preparation of complex 1-12

The hydrochloride (50mg, 0.11mmol) of compound 1-11 was dissolved in 5mL of methanol, then cobalt acetate tetrahydrate (29mg, 0.12mmol) was added, and reacted overnight at room temperature, gradually a precipitate was formed, collected after centrifugation, and then The precipitate was washed by adding 5 mL of methanol, collected and dried to obtain a dark green solid (15 mg), namely compound 1-12, with a yield of 22%. Iron, cobalt, and nickel are paramagnetic and are not suitable for NMR characterization.

HRMS (ESI) Theoretical C ₃₀ H ₁₆ CoN ₄ ²⁺ [M/Z] ⁺ : 245.5348; Found: 245.5349.

Embodiment 9, the preparation of complex 1-13

The hydrochloride of compound 1-11 (50mg, 0.11mmol) was dissolved in 5mL of methanol, then copper sulfate pentahydrate (30mg, 0.12mmol) was added, and reacted overnight at room temperature, gradually a precipitate was formed, collected after centrifugation, and then The precipitate was washed by adding 5 mL of methanol, collected and dried to obtain a solid (28 mg), namely compound 1-13, with a yield of 49%.

HRMS (ESI) Theoretical C ₃₀ H ₁₆ N ₄ Cu ²⁺ [M/Z] ²⁺ : 247.5330; Found: 247.5332.

Embodiment 10, the preparation of complex 1-14

Dissolve the hydrochloride salt of compound 1-11 (50mg, 0.11mmol) in 5mL of methanol, then add anhydrous ferric chloride (20mg, 0.12mmol), react at room temperature overnight, gradually precipitates, after centrifugation, then collect The solid was washed with 5 mL×2 methanol, collected and dried to obtain a tan solid (25 mg), which was compound 1-14, with a yield of 38%.

HRMS (ESI): Theoretical C ₃₀ H ₁₆ N ₄ FeCl ₂ ⁺ [M/Z] ⁺ : 558.0096; Found: 558.0100.

Example 11, Carbon Dioxide Reduction (CO ₂ RR) Catalytic Activity Measurement and Comparison

Preparation of catalyst ink: Dissolve 2 mg of complexes 1-12 (Co-N ₄ complexes) in 1.95 mL of N,N-dimethylformamide, then add 8 mg of carbon nanotubes (C-Nano, FT 9000) and 0.05 mL perfluorosulfonic acid polymer (Nafion) solution. The mixture is ultrasonicated for more than 3 hours, so that the complex and the carbon nanotubes are completely combined in the form of covalent bonds.

Add an appropriate amount of catalyst ink dropwise on a 1×1cm ² hydrophilic carbon cloth, heat and dry appropriately. The carbon cloth loaded with the catalyst was used as the working electrode, the platinum sheet was used as the counter electrode, and the Ag/AgCl/saturated KCl solution was used as the reference electrode. The electrolyte concentration is 0.1M potassium bicarbonate solution. The H-type electrolytic cell was used to test the performance of the complex for catalytic reduction of carbon dioxide.

At the same time, the cobalt complex Co(II)CPY was used as comparative example 1 (Angew Chem Int Ed Engl.2020Sep21; 59(39):17104-17109.), and its structural formula is as follows:

Catalyst ink was prepared by referring to the above method and its catalytic carbon dioxide reduction performance was tested to compare with complexes 1-12.

The result is shown in Figure 2. It can be seen from the figure that, compared with the existing conjugated N4-macrocyclic cobalt complexes, the cobalt complexes provided in the examples of the present application show more excellent catalytic activity for carbon dioxide reduction (CO ₂ RR) as a whole, Especially the catalytic activity of carbon dioxide reduction to CO. Specifically, the complex 1-12 has the highest current density in CO at around -1.09V, which is higher than 45mA·cm ^-2 , and the reduction reaction selectivity is better, and the CO faradaic efficiency reaches up to 88%. In comparison example 1, the CO fraction current density is the largest at only 30mA ^. cm ^-2 , which is much lower than that of complexes 1-12. However, the catalytic activity of the cobalt complex Co(II) CPY for carbon dioxide reduction reaction is higher than that of existing phthalocyanine or porphyrin catalysts. It can be seen that the catalytic activity of the electrocatalytic carbon dioxide reduction complex provided by the examples of this application is far Higher than existing porphyrin or phthalocyanine catalysts. The reason may be that the ligands provided in the examples of this application are electrically neutral ligands, while the existing porphyrin, phthalocyanine or Co(II) CPY are all anionic ligands because they need to remove two protons. At the same time, affected by various factors such as the structure of its mother nucleus, it finally has a more excellent catalytic activity for carbon dioxide reduction.

Embodiment 12, Oxygen Reduction (ORR) Catalytic Activity Determination

The catalyst ink was prepared according to the method in Example 11, so that the complex was completely combined with the carbon nanotubes.

10 μL of catalyst ink was dropped onto the disk electrode of the rotating ring disk electrode as the working electrode, the ring electrode was a platinum ring, the platinum wire was used as the counter electrode, and Hg/HgO was used as the reference electrode. The electrolyte concentration is 0.1M potassium hydroxide solution. The rotational speed of the rotating ring-disk electrode was 1600 rpm. The carbon nanotubes without complex 1-12 (Co-N ₄ complex) were used as the control group (CNTs), and the carbon nanotubes with complex 1-12 (Co-N ₄ complex) were added as the experimental group (Coqpy +CNTs).

The results are shown in Figure 3. It can be seen from the figure that the current density of the experimental group increases rapidly near 0.8V (vs. RHE), while the current density of the control group does not increase significantly. Oxygen reduction reaction product selectivity and average electron transfer numbers were calculated from ring currents. The hydrogen peroxide selectivity of the experimental group is about 50%, and the average electron transfer number is about 3. Therefore, the complex also has good catalytic activity as a catalyst for oxygen reduction reaction, especially the catalytic activity for oxygen reduction catalysis to generate hydrogen peroxide.

Example 13

This embodiment provides a ligand 1-11a and complex 1-12a, the difference from the complex 1-12 provided in Example 8 is that during the synthesis, 2,9-dichlorophenanthroline (compound 1 -5) replaced by 2,9-dichloro-1,10-phenanthroline-5,6-dione (compound 1-5a), the specific reaction for preparing compound 1-51 from compound 1-5 is as follows:

The structural formulas of ligand 1-11a and complex 1-12a are as follows:

Example 14

This example provides a ligand 1-11b and complex 1-13b, which uses 2,9-dichloro-4,7-diphenyl-1,10-phenanthroline to replace compound 1-5 to synthesize the ligand 1-11b. Its structural formula is as follows:

Example 15

This embodiment provides a ligand 1-11c and a complex 1-15c, the structural formula of which is as follows:

Example 16

This embodiment provides a ligand 1-11d and a complex 1-16d, the structural formula of which is as follows:

The above-mentioned examples 13-16 can be prepared by selecting appropriate materials according to the methods of the previous examples or other methods well known in the art.

The complexes provided in Examples 13-16 are tested according to the method of Examples 11-12, and they also have good catalytic activities for electrocatalyzing carbon dioxide reduction reaction and oxygen reduction reaction, and will not be repeated here.

The present application has been described in detail above in conjunction with the embodiments, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge of those of ordinary skill in the art without departing from the gist of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other under the condition of no conflict.

Claims (9)

1. Ligand, it is characterized in that, the structural formula of described ligand is as shown in formula I:

Wherein, R ¹ , R ² , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are independently selected from hydrogen atom, halogen atom, carbonyl group, hydroxyl group, aldehyde group, carboxyl group, nitro group, amino group, pyrazinyl group, C _{1- 30} alkyl, C _1-30 alkylamino, C 3-30 cycloalkyl, C _1-30 alkoxy, C _3-30 cycloalkyloxy _, C _6-40 aryl, C _6-40 aryl Baseoxy, C _6-40 arylamino, and adjacent groups in R ¹ , R ² , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ can be connected to each other to form a ring; Preferably, R ¹ , R ² , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are independently selected from hydrogen atom, halogen atom, carbonyl, hydroxyl, aldehyde, nitro, carboxyl, amino, pyrazinyl, C _{1 -20} alkyl, C ₁ -C ₂₀ alkylamino, C _1-20 alkoxy, C _6-30 aryl, C _6-30 aryloxy, C _6-30 arylamino; Preferably, R ¹ , R ² , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are each independently selected from a hydrogen atom, a halogen atom, a methyl group, an ethyl group, a carbonyl group, an aldehyde group, a carboxyl group, and an amino group; Preferably, R ¹ and R ² can be connected to each other to form a ring, and/or, R ⁸ and R ⁹ can be connected to each other to form a ring, and/or, R ¹⁰ and R ¹¹ can be connected to each other to form a ring; Preferably, R ¹ and R ² are independently selected from a hydrogen atom, a halogen atom, a methyl group, an ethyl group, a carbonyl group, an amino group, or R ¹ and R ² are connected to each other to form a dioxolane; Preferably, R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are all hydrogen atoms. 2. The preparation method of the ligand described in claim 1, is characterized in that, comprises the following steps:

S1: react compound III with compound IV to obtain compound V; S2: compound V reacts with compound IX to obtain compound VI; S3: compound VI is oxidized to obtain compound VII; S4: compound VII is deprotected to obtain compound VIII; S5: compound VIII reacts with compound X to obtain a ligand represented by formula I; Wherein, R ³ and R ⁴ are independently selected from halogen atom, alkyl tin, boron group; R ⁵ and R ⁶ are independently selected from boronic acid groups and halogen atoms; R ⁷ is C _1-30 alkyl; Z is an amino protecting group; Preferably, ^R3 and ^R4 are independently selected from chlorine atom, bromine atom, butyl tin, methyl tin, boric acid group, boric acid pinacol ester; Preferably, the catalyst in S1 and/or S2 is a palladium catalyst; Preferably, the palladium catalyst is selected from tetrakis(triphenylphosphine)palladium, bis(triphenylphosphine)palladium dichloride, 1,1'-bis(diphenylphosphine)ferrocenepalladium dichloride, At least one of bis(dibenzylideneacetone)palladium, tris(dibenzylideneacetone)dipalladium, bis(tricyclohexylphosphine)palladium dichloride; Preferably, the temperature of the coupling reaction in S1 and/or S2 is 60-150°C; Preferably, in S3: the oxidizing agent is selenium dioxide; and/or; the reaction temperature is 60-100°C; and/or, the reaction solvent is dioxane; Preferably, in S4: the deprotection reaction is an acidic condition; and/or; the acidic condition is provided by trifluoroacetic acid; and/or, the solvent is dichloromethane; and/or, the volume ratio of trifluoroacetic acid and dichloromethane is 1: (1~4). 3. The complex, characterized in that the structural formula of the complex is as shown in formula II:

Wherein, M is a metal cation, X is an anion, and n is the ratio of the valence state of M to the valence state of X; Preferably, M is a cation of a transition metal element, and/or, X is a halide ion, carboxylate ion, sulfate ion, sulfite ion, hydroxide ion, nitrate ion, phosphate ion, monohydrogen phosphate ions, dihydrogen phosphate ions, carbonate ions, bicarbonate ions, chlorate ions, perchlorate ions, iodate ions, and periodate ions. 4. the preparation method of complex described in claim 3 is characterized in that, comprises the following steps: Get the ligand described in claim 1 or the ligand prepared according to the preparation method described in claim 2; The ligand is complexed with MX _n in a solvent to form a complex shown in formula II. 5. The catalyst, characterized in that it comprises the complex as claimed in claim 3. 6. An electrode or an electrolyte, characterized in that it comprises the complex according to claim 3, or comprises the catalyst according to claim 5. 7. device, is characterized in that, comprises the complex described in claim 3, or comprises the catalyst described in claim 5, or comprises the electrode or electrolyte solution described in claim 6; Preferably, the device is selected from any one of fuel cells and carbon dioxide electrolyzers. 8. The reduction method of gas, it is characterized in that, comprise complex compound described in claim 3 or the catalyzer described in claim 5 are mixed with described gas, electrocatalytic reduction described gas; Said gas is selected from carbon dioxide, oxygen any of the. 9. The part as claimed in claim 1, or the complex as claimed in claim 3, or the application of the catalyst as claimed in claim 5 in electrochemical reaction; Preferably, the electrochemical reaction is any one of carbon dioxide reduction reaction and oxygen reduction reaction.

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