JP7317303B2 - Ammonia decomposition method and ruthenium complex - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for decomposing ammonia and a ruthenium complex.

Ammonia is relatively easy to handle, does not contain carbon, and does not emit carbon dioxide when burned. Therefore, its use as an energy carrier is attracting attention toward the future carbon-free society. Ammonia as an energy carrier has the potential to be sufficiently competitive with conventional energy in terms of cost, carbon dioxide emissions, and energy efficiency. However, in order to put ammonia into practical use as an energy carrier, it is necessary to oxidatively decompose ammonia to take out nitrogen molecules, electrons, and protons. As this type of ammonia decomposition reaction, there are reports of catalytic reactions using solid catalysts such as Ni—Gd, Pt, and Ru—Al (Non-Patent Documents 1 to 3).

J. Power Sources 2016, vol.305, p72 J. Mater. Chem., 2013, vol. 1, p3216 Sci. Adv. 2017, vol.3, e1602747

However, all of the above-mentioned reported examples have the problem of requiring high temperature, high pressure or overvoltage.

The present invention has been made to solve the above-described problems, and the main object thereof is to extract nitrogen molecules, electrons, and protons by decomposing ammonia under milder conditions than conventional ones.

In order to achieve the above object, the present inventors have found that nitrogen, protons and electrons can be efficiently obtained by oxidative decomposition of ammonia in the presence of a base using a certain ruthenium complex as a catalyst. , have completed the present invention.

That is, the method for decomposing ammonia of the present invention is a method for decomposing ammonia to obtain nitrogen, protons and electrons by oxidatively decomposing ammonia in the presence of a catalyst and a base, wherein the catalyst comprises two primary ligands and one second ligand, wherein the first ligand is pyridine or a pyridine-condensed cyclic compound that may have a substituent, and the second ligand is , 2,2'-bipyridyl-6,6'-dicarboxylic acid optionally having a substituent on the pyridine ring.

According to this method of decomposing ammonia, nitrogen, protons and electrons can be obtained from ammonia under milder conditions than conventional methods.

（式中、Ｐｙは、４位にアルキル基、アルコキシ基、アリール基若しくはハロゲン原子を有していてもよいピリジン又は６位にアルキル基、アルコキシ基、アリール基若しくはハロゲン原子を有していてもよいイソキノリンであり、Ｒはアルキル基、アルコキシ基、アリール基又はハロゲン原子であり、Ｘは１価のアニオンである）のいずれかで表されるルテニウム錯体が挙げられる。As catalysts, for example, formulas (A) to (C)

(Wherein, Py is a pyridine optionally having an alkyl group, an alkoxy group, an aryl group or a halogen atom at the 4-position or an alkyl group, an alkoxy group, an aryl group or a halogen atom at the 6-position is a good isoquinoline, R is an alkyl group, an alkoxy group, an aryl group or a halogen atom, and X is a monovalent anion).

The ruthenium complex of formula (B) is obtained by one-electron oxidation of the ruthenium complex of formula (A) and coordination with ammonia. The ruthenium complex of formula (C) is a nitrogen complex formed after repeated one-electron oxidation and deprotonation of the ruthenium complex of formula (B). The ruthenium complexes of formulas (B) and (C) are intermediates (novel compounds) produced in the oxidative decomposition of ammonia by the ruthenium complex of formula (A), and actually function as catalysts.

Graphs of current-potential curves of Experimental Examples 28 and 29. FIG. Graphs of current-potential curves of Experimental Examples 28 and 32. FIG.

Preferred embodiments of the method for decomposing ammonia and the ruthenium complex of the present invention are shown below.

The method for decomposing ammonia of the present embodiment is a method for decomposing ammonia to obtain nitrogen, protons, and electrons by oxidatively decomposing ammonia in the presence of a catalyst and a base (see the following formula). A ruthenium complex having a ligand and one secondary ligand, wherein the primary ligand is pyridine or a pyridine-fused ring compound optionally having a substituent, and the secondary ligand is 2,2′-bipyridyl-6,6′-dicarboxylic acid optionally having a substituent on the pyridine ring.

In the ammonia decomposition method of the present embodiment, the catalyst is a ruthenium complex having two primary ligands and one secondary ligand. The first ligand is optionally substituted pyridine or a pyridine-fused ring compound. As the first ligand, for example, pyridine, isoquinoline, quinoline, etc., pyridine having a substituent at at least one of the 2- to 6-positions, and a substituent at at least one of the 1- and 3- to 8-positions. and isoquinoline having a substituent at at least one of the 2- to 8-positions. Examples of substituents include, but are not limited to, alkyl groups, alkoxy groups, aryl groups, and halogen atoms. Examples of alkyl groups include linear or branched alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl and structural isomers thereof, and cyclopropyl. cyclic alkyl groups such as groups, cyclobutyl groups, cyclopentyl groups and cyclohexyl groups. The alkyl group preferably has 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms. The alkoxy group may be, for example, a linear or branched alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, a hexyloxy group, and structural isomers thereof; A cyclic alkoxy group such as a propoxy group, a cyclobutoxy group, a cyclopentoxy group, and a cyclohexyloxy group may be used. The alkoxy group preferably has 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms. Aryl groups include, for example, phenyl groups, tolyl groups, xylyl groups, naphthyl groups, and those in which at least one hydrogen atom on the ring thereof is substituted with an alkyl group or a halogen atom. Halogen atoms include, for example, fluorine, chlorine, bromine and iodine atoms. The second ligand is 2,2'-bipyridyl-6,6'-dicarboxylic acid optionally having a substituent on the pyridine ring. As the second ligand, in addition to 2,2'-bipyridyl-6,6'-dicarboxylic acid, at least one of the 3-position to 5-position and the 3'-position to 5'-position of the pyridine ring has a substituent. and 2,2'-bipyridyl-6,6'-dicarboxylic acid. Examples of substituents include, but are not limited to, alkyl groups, alkoxy groups, aryl groups, and halogen atoms. Specific examples thereof are the same as those already exemplified. Such a catalyst may be used in a catalytic amount with respect to ammonia. For example, it is preferable to use 0.001 to 0.1 times the number of moles of ammonia, and use 0.002 to 0.01 times the number of moles of ammonia. is more preferable.

（式中、Ｐｙは、４位にアルキル基、アルコキシ基、アリール基若しくはハロゲン原子を有していてもよいピリジン又は６位にアルキル基、アルコキシ基、アリール基若しくはハロゲン原子を有していてもよいイソキノリンであり、Ｒはアルキル基、アルコキシ基、アリール基又はハロゲン原子であり、Ｘは１価のアニオンである）のいずれかで表されるルテニウム錯体が好ましい。式中のアルキル基、アルコキシ基、アリール基、ハロゲン原子としては、既に例示したものと同じものが挙げられる。１価のアニオンとしては、例えば、ヘキサフルオロホスファートイオン、ヘキサクロロアンチモナートイオン、トリフルオロメタンスルホナートイオン、テトラフルオロボラートイオン、ホスフェートイオン、スルホナートイオン、クロリド、ブロミド、ヨージド、ヒドロキシドなどが挙げられる。このうち、式（Ｂ），（Ｃ）のルテニウム錯体は新規化合物である。As catalysts, formulas (A) to (C)

(Wherein, Py is a pyridine optionally having an alkyl group, an alkoxy group, an aryl group or a halogen atom at the 4-position or an alkyl group, an alkoxy group, an aryl group or a halogen atom at the 6-position is a good isoquinoline, R is an alkyl group, an alkoxy group, an aryl group or a halogen atom, and X is a monovalent anion). Examples of the alkyl group, alkoxy group, aryl group, and halogen atom in the formulas include those already exemplified. Examples of monovalent anions include hexafluorophosphate ion, hexachloroantimonate ion, trifluoromethanesulfonate ion, tetrafluoroborate ion, phosphate ion, sulfonate ion, chloride, bromide, iodide, and hydroxide. be done. Among these, the ruthenium complexes of formulas (B) and (C) are novel compounds.

In the ammonia decomposition method of the present embodiment, the base plays a role of trapping protons generated when ammonia is oxidatively decomposed. The base is not particularly limited as long as it fulfills such a role, but pyridine derivatives are preferred, for example. Examples of pyridine derivatives include pyridine and pyridine having at least one substituent on the 2- to 6-positions. Examples of substituents include, but are not limited to, alkyl groups, dialkylamino groups, alkoxy groups, aryl groups, and halogen atoms. Examples of the alkyl group (including the alkyl group in the dialkylamino group), alkoxy group, aryl group, and halogen atom are the same as those already exemplified. Specific examples of pyridine derivatives include pyridine, 2,6-lutidine, 2,4,6-collidine, and 4-dimethylaminopyridine (DMAP), among which 2,4,6-collidine is preferred. When ammonia is produced in the system by the reaction of an ammonium salt and a base, the base is also used in this reaction.

In the method for decomposing ammonia according to the present embodiment, ammonia gas may be used, but ammonia may also be generated by reaction between an ammonium salt and a base in the system. When it is necessary to quantify ammonia, it is preferable to generate ammonia in the system as in the latter case. The ammonium salt is not particularly limited as long as it quantitatively produces ammonia by reaction with a base. ammonium hydroxide, ammonium acetate, ammonium sulfate, ammonium phosphate and the like.

In the method for decomposing ammonia of the present embodiment, oxidative decomposition of ammonia may be performed using an oxidizing agent containing a one-electron oxidant of triarylamine, or may be performed under electrochemical oxidation conditions. An oxidizing agent containing a one-electron oxidant of triarylamine plays a role of trapping electrons generated when ammonia is oxidatively decomposed. An example of such an oxidizing agent is shown in formula (D). In formula (D), R ¹ and R ² , which may be the same or different, are alkyl groups, halogen atoms or hydrogen atoms. Examples of the alkyl group and halogen atom include those already exemplified. Of these, those in which R ¹ is a bromine atom and R ² is a hydrogen atom are preferred. Y is a monovalent anion such as hexachloroantimonate ion, hexafluorophosphate ion, chloride, bromide, iodide, hydroxide, phosphate ion, sulfonate ion, and trifluoromethanesulfonate ion.

In the method for decomposing ammonia of the present embodiment, oxidative decomposition of ammonia may be performed in a solvent. Examples of the solvent include, but are not limited to, nitrile solvents, halogenated hydrocarbon solvents, ketone solvents, alcohol solvents, cyclic ether solvents, chain ether solvents, and water. Examples of nitrile solvents include acetonitrile and propionitrile. Halogenated hydrocarbon solvents include, for example, methylene chloride and chloroform. Examples of ketone-based solvents include acetone and methyl ethyl ketone. Examples of alcoholic solvents include methanol and ethanol. Cyclic ether solvents include, for example, tetrahydrofuran (THF) and 1,4-dioxane. Examples of chain ether solvents include diethyl ether.

In the method for decomposing ammonia of the present embodiment, the oxidative decomposition of ammonia proceeds even if the reaction temperature is lower than in the conventional method. For example, the reaction proceeds even at normal temperature (room temperature), 0°C, and -20°C. The reaction atmosphere may be, for example, an inert atmosphere (such as an Ar atmosphere) or the air. Moreover, it is not necessary to use a pressurized atmosphere, and a normal pressure atmosphere may be used. Although the reaction time is not particularly limited, it may usually be set in the range of several tens of minutes to several tens of hours.

In the ammonia decomposition method of the present embodiment, the reaction mechanism of oxidative decomposition of ammonia is thought to proceed as shown in the scheme below. This scheme illustrates the case where the ruthenium complex Ru(II) of formula (A) is used as a catalyst. First, the ruthenium complex of formula (A) undergoes one-electron oxidation and then coordinated with ammonia to produce [Ru(III)-NH ₃ ], which is the ruthenium complex of formula (B). Thereafter, one-electron oxidation and deprotonation are repeated to produce [Ru(IV)-NH ₂ ], [Ru(V)=NH], and [Ru(VI)≡N] in sequence. Subsequent dimerization of [Ru(VI)≡N] or post-dimerization deprotonation of Ru(V)=NH] results in the ruthenium complex of formula (C) [Ru(IV)=N =N=Ru(IV)]. Nitrogen in [Ru(IV)=N=N=Ru(IV)] returns to [Ru(III)-NH ₃ ] by exchanging with ammonia. That is, the ligand exchange reaction produces nitrogen and introduces new ammonia into the catalytic reaction cycle.

As can be seen from the above reaction mechanisms, the ruthenium complexes of formulas (B) and (C) are intermediates produced in the process of oxidative decomposition of ammonia by the ruthenium complex of formula (A), and they also function as catalysts.

It goes without saying that the present invention is not limited to the above-described embodiments, and can be implemented in various forms as long as they fall within the technical scope of the present invention.

Examples of the present invention are described below. In addition, the following examples do not limit the present invention.

[Experimental Example 1-25]
An attempt was made to oxidatively decompose ammonia using a catalyst, an oxidizing agent, and a base (see Table 1). Ammonia was generated in the system by the reaction of NH ₄ OTf and a base. The Ru complexes (1a), (2a), (2b), and (3), whose chemical formulas are shown in the margins of Table 1, are disclosed in known literature (Nat. Chem. 2012, vol. 4, p418, J. Am. Chem. 2009, vol. 31, p10397, Inorg. Chem. 2012, vol. 51, p2930, J. Am. Chem. Soc. 2006 vol. 128, p7761).

In Experimental Example 1, 0.01 mmol of Ru complex (2a), 3.0 mmol of NH ₄ OTf as an ammonium salt, and [(p-BrC ₆ H ₄ ) ₃ N ^· ] ⁺ [SbCl ₆ ] ⁻ ( 4a) 0.9 mmol and 3.0 mmol of 2,4,6-collidine as a base were stirred in 5 mL of acetonitrile under an Ar atmosphere of 1 atm at −40° C. for 2 hours and then at room temperature for 4 hours. . As a result, 12.0 equivalents of nitrogen (80% yield based on oxidant) were confirmed.

In Experimental Example 2-4, [(p-MeC ₆ H ₄ ) ₃ ^N. ] ⁺ [SbCl ₆ ] ⁻ (4b) and [(2,4-Br ₂ C ₆ H ₃ ) ₃ ^N. ] ⁺ [SbCl ₆ ] ⁻ (4c), Cp ₂ FeOTf were investigated. As a result, although the reaction proceeded with any of the oxidants, the yield was high when the triarylammonium-based oxidant was used, and the yield was particularly high when the oxidant (4a) of Experimental Example 1 was used. rice field.

In Experimental Example 5-7, pyridine, 2,6-lutidine, and 4-dimethylaminopyridine (DMAP) were examined as bases. As a result, the reaction proceeded with any base, but 2,4,6-collidine of Experimental Example 1 was the most suitable.

In Experimental Example 8-10, 3.9 mmol, 6.0 mmol, and 2.0 mmol were examined as the amount of base to be added. As a result, although the reaction progressed in any amount added, 3.0 mmol in Experimental Example 1 was optimal.

In Experimental Examples 11-15, methylene chloride, acetone, methanol, ethanol, and THF were investigated as solvents. As a result, the reaction proceeded with any solvent, but acetonitrile of Experimental Example 1 was the most suitable.

In Experimental Examples 16 and 17, the cooling temperature was -20°C and 0°C. As a result, although the reaction proceeded at any cooling temperature, −40° C. in Experimental Example 1 was optimal. It is considered that this is because the consumption of the oxidizing agent by the base is suppressed at lower temperatures.

Experimental example 18 without a base, experimental example 19 without an oxidizing agent, experimental example 20 without NH ₄ OTf, and experimental example 21 without a catalyst were examined. As a result, it was confirmed that nitrogen was not generated in Experimental Examples 18-21.

Examples 22-24 were studied using catalysts (1a), (2b) and (3) under optimized conditions (ie, Example 1). As a result, the Ru complex (2b) of Experimental Example 23 also efficiently generated nitrogen, but the Ru complex (2a) of Experimental Example 1 exhibited higher activity. On the other hand, the catalysts (1a) and (3) of Experimental Examples 22 and 24 hardly promoted the decomposition of ammonia.

In Experimental Example 25, the reaction was carried out in the same manner as in Experimental Example 1 except that NH ₄ PF ₆ was used instead of NH ₄ OTf. As a result, 10.8 equivalents (yield 72%) of nitrogen was confirmed. From this, it was found that NH ₄ PF ₆ can also be sufficiently used as an ammonia source.

[Experimental example 26]
Ru complex (2c) (Py=4-methylpyridine, R=H, X=PF ₆ ⁻ in formula (B)) was synthesized according to the following formula. That is, first, Ru complex (2e) was synthesized by one-electron oxidation of Ru complex (2b) following the synthesis example described in the literature (Chem. Commun. 2016, vol.52, p8619). Next, Ru complex (2e) (65.0 mg, 0.10 mmol) was stirred in an ammonia-methanol solution (2 M, 2 mL) for 10 minutes. Then, by recrystallization using methanol-diethyl ether, Ru complex (2c) was obtained as a crystalline solid (61.0 mg, yield 83%). Spectral data of Ru complex (2c) are as follows.
^1H NMR ( _CD3CN ): 44.6(s), 4.5(br), 1.48(br)

In Experimental Example 1, the Ru complex (2c) was used instead of the Ru complex (2a), and the oxidative decomposition of ammonia was attempted in the same manner as in Experimental Example 1. Table 2 shows the results. Table 2 also shows the results of Experimental Examples 1 and 23 using Ru complexes (2a) and (2b). As is clear from Table 2, Ru complex (2c) was found to have catalytic activity comparable to Ru complexes (2a) and (2b).

[Experimental example 27]
Ru complex (5) (Py=4-methylpyridine, R=H, X=PF ₆ ⁻ in formula (C)) was synthesized according to the following formula. That is, under an argon atmosphere, Ru complex (2b) (53.0 mg, 0.10 mmol), 2,4,6-collidine (0.13 mL, 1.0 mmol), ammonium triflate (146. 7 mg, 1.0 mmol) was added, and 4 mL of acetonitrile was added. After that, while stirring the solution, [(p-BrC ₆ H ₄ ) ₃ ^N. ] ⁺ [SbCl ₆ ] ⁻ (4a) (326.4 mg, 0.4 mmol) dissolved in 1 mL of acetonitrile was added dropwise. Stir for a minute. A saturated NH ₄ PF ₆ aqueous solution (10 mL) was added to the reaction solution, and the mixture was allowed to stand overnight. The solution was filtered, washed with water (10 mL×3), and then extracted with methanol to obtain an orange-brown solution. The orange-brown solution was concentrated under reduced pressure and washed again with THF to obtain Ru complex (5) as an orange-brown solid. Spectral data of Ru complex (5) are as follows.
ESI-TOF-MS (MeOH): m/z = 1088.1 (calculated value 1088.1)

[Experimental Examples 28 and 29]
In Experimental Example 28, cyclic voltammetry (CV) measurements were performed to obtain knowledge about the decomposition of ammonia under electrochemical oxidation conditions. That is, using a Glassy Carbon electrode as a working electrode and [nBu ₄ N][PF ₆ ] as a supporting electrolyte, 0.01 mmol (1 mM) of Ru complex (2a), 2,4, CV measurement was performed at a scan rate of 1 mV/s in the presence of 6.0 mmol of 6-collidine and 6.0 mmol of NH ₄ OTf. A graph of the obtained current-potential curve is shown in FIG. From this graph, a steady current was confirmed in the oxidative decomposition of ammonia. Its value was 200 μA. The same steady-state current was obtained even when the scanning speed was halved to 0.5 mV/s. As a comparative example (Experimental Example 29), CV measurement was performed in the same manner without the Ru complex. As a result, the graph shown in FIG. 1 was obtained, and no steady current was observed. From these results, it was confirmed that the oxidative decomposition of ammonia proceeds even under electrochemical oxidation conditions.

[Experimental Examples 30 and 31]
A Ru complex (2f) having a methoxy group at the 4-position of pyridine was synthesized according to a method known in the literature (Inorg. Chem. 2013, 52, 7844). The oxidation reaction of ammonia was carried out as shown in Table 3 using the complex (2f). In Experimental Example 30, [(p-BrC ₆ H ₄ ) ₃ N ^· ] ⁺ [SbCl ₆ ] ⁻ (4a) (1.80 mmol), ammonium triflate (6. 0 mmol) and acetonitrile (4.5 mL) were added followed by 2,4,6-collidine (6.0 mmol). After that, complex (2f) (0.005 mmol) dissolved in acetonitrile (0.5 mL) was added, and the mixture was stirred at room temperature for 1.5 hours. As a result, nitrogen was obtained with a yield of 87% per oxidant. Further, in Experimental Example 31, after stirring at −40° C. for 2 hours, stirring was performed at room temperature for 4 hours for reaction.

[Experimental example 32]
Ru complex (2g) having a fluoro group at the 6-position of the isoquinoline ring of Ru complex (2a) was prepared according to a method known in the literature (Chem. Commun. 2014, 50, 12947). Ammonia oxidative decomposition under electrochemical oxidation conditions was carried out in the same manner as in Example 28 using the complex (2 g). As a result, as shown in FIG. 2, even when the complex (2g) was used, the stationary current in the catalytic reaction was confirmed in the same manner as when the complex (2a) was used, and the progress of the catalytic reaction was confirmed. Its catalytic current value was 543 μA.

[Experimental Examples 33 and 34]
Catalytic reactions were carried out using ammonia as the ammonia source. In Experimental Example 33, [(p-BrC ₆ H ₄ ) ₃ N ^· ] ⁺ [SbCl ₆ ] ⁻ (4a) (0.90 mmol), ammonia (3.0 mmol) and ) and acetonitrile (4.5 mL) were added, complex 2a (0.005 mmol) dissolved in acetonitrile (0.5 mL) was added, and the mixture was stirred at −40° C. for 2 hours and then stirred at room temperature for 4 hours. , reacted. As a result, nitrogen was confirmed at a yield of 73% per oxidant. Further, in Experimental Example 34, 2,4,6-collidine (6.0 mmol) was added under these reaction conditions and the reaction was carried out, and 93% of nitrogen was confirmed per oxidant.

Incidentally, Experimental Examples 1-17, 23, 25-28, and 30-34 correspond to Examples of the present invention, and Experimental Examples 18-22, 24, and 29 correspond to Comparative Examples.

This application claims priority from Japanese Patent Application No. 2018-36966 filed on March 1, 2018, the entire contents of which are incorporated herein by reference.

INDUSTRIAL APPLICABILITY The present invention can be used for decomposing ammonia.

Claims (11)

A method of decomposing ammonia by oxidatively decomposing ammonia using an oxidizing agent in the presence of a catalyst and a base or by oxidatively decomposing ammonia under electrochemical oxidation conditions to obtain nitrogen, protons and electrons,
The catalyst is a ruthenium complex having two primary ligands and one secondary ligand, and the primary ligand is an optionally substituted pyridine or pyridine-fused cyclic a compound, wherein the second ligand is 2,2'-bipyridyl-6,6'-dicarboxylic acid optionally having a substituent on the pyridine ring;
the base is a pyridine derivative,
Method for decomposing ammonia.
The catalyst has formulas (A) to (C)

(Wherein, Py is a pyridine optionally having an alkyl group, an alkoxy group, an aryl group or a halogen atom at the 4-position or an alkyl group, an alkoxy group, an aryl group or a halogen atom at the 6-position is a good isoquinoline, R is an alkyl group, an alkoxy group, an aryl group or a halogen atom, and X is a monovalent anion).
The method for decomposing ammonia according to claim 1. The ammonia is generated in the system by a reaction between an ammonium salt and a base,
The method for decomposing ammonia according to claim 1 or 2. The catalyst uses 0.001 to 0.1 times the number of moles of ammonia,
The method for decomposing ammonia according to any one of claims 1 to 3. The base is pyridine optionally having a substituent at at least one of the 2- to 6-positions.
The method for decomposing ammonia according to any one of claims 1 to 3. the base is 2,4,6-collidine;
The method for decomposing ammonia according to claim 5. The oxidative decomposition of ammonia is performed by using an oxidizing agent containing a one-electron oxidant of triarylamine.
The method for decomposing ammonia according to any one of claims 1 to 6. the aryl group contained in the oxidizing agent is a phenyl group having an alkyl group or a halogen atom at the 2- and/or 4-position;
The method for decomposing ammonia according to claim 7. The oxidative decomposition of ammonia is performed under electrochemical oxidation conditions.
The method for decomposing ammonia according to any one of claims 1 to 6. Formula (B)

(Wherein, Py is a pyridine optionally having an alkyl group, an alkoxy group, an aryl group or a halogen atom at the 4-position or an alkyl group, an alkoxy group, an aryl group or a halogen atom at the 6-position a good isoquinoline, R is an alkyl group, an alkoxy group, an aryl group or a halogen atom, and X is a monovalent anion). Formula (C)

(Wherein, Py is a pyridine optionally having an alkyl group, an alkoxy group, an aryl group or a halogen atom at the 4-position or an alkyl group, an alkoxy group, an aryl group or a halogen atom at the 6-position a good isoquinoline, R is an alkyl group, an alkoxy group, an aryl group or a halogen atom, and X is a monovalent anion).

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