JP2007031390A - Method for producing ruthenium complex - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for easily producing in high productivity a ruthenium complex with a specific structure useful as a raw material for materials for optoelectronic conversion devices. <P>SOLUTION: The method for producing the ruthenium complex comprises conducting a reaction between 4,4'-dicarboxy-2,2'-bipyridine, ruthenium chloride and an alcohol of the formula(1):R-OH( wherein, R is methyl or ethyl ) at 85°C or higher. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a ruthenium complex having an ester group, and more specifically, the formula (2):

（式中、Ｒはメチル基又はエチル基を示し、Ｒ^１、Ｒ^２及びＲ^３は水素原子又はＲを示す。）で表されるルテニウム錯体（以下、ルテニウム錯体（２）という。）の製造方法に関する。

(In the formula, R represents a methyl group or an ethyl group, and R ¹ , R ^2, and R ³ represent a hydrogen atom or R.) Production of a ruthenium complex (hereinafter referred to as a ruthenium complex (2)). Regarding the method.

  The ruthenium complex (2) is useful as a raw material for photoelectric conversion element materials such as dye-sensitized wet solar cells and optical electronic materials (see, for example, Non-Patent Documents 1 to 4). Conventionally, as a method for producing a ruthenium complex (2), 1) 4,4′-dicarboxy-2,2′-bipyridine and methanol or ethanol are esterified, and the corresponding 4,4′-dialkyloxycarbonyl is produced. After obtaining 2,2′-bipyridine, the obtained 4,4′-dialkyloxycarbonyl-2,2′-bipyridine is heated and refluxed in ruthenium chloride and an ethanol solvent (for example, Non-Patent Documents 1 and 2). 2) A method in which 4,4′-dicarboxy-2,2′-bipyridine and ruthenium chloride are heated to reflux in an ethanol solvent in the presence of lithium chloride and concentrated hydrochloric acid (for example, Non-Patent Document 4). See).

However, since the production method 1) needs to be carried out in two steps, the operation becomes complicated, and the production method 2) requires lithium chloride and concentrated hydrochloric acid in addition to the reactants and is not economically satisfactory. This method is not industrially advantageous. In addition, when the reaction of 2) was carried out without using lithium chloride and concentrated hydrochloric acid, the target ruthenium complex (2) was produced only in a small amount (see Comparative Example 1 described later).
Chem. Mater. 9,430 (1997) Inorg. Chem. , 41, 6258 (2002) Chem. Mater. , 13, 1023 (2001) Inorganica Chimica Acta, 263, 395 (1997)

  An object of the present invention is to provide a method for producing a ruthenium complex (2) with a high yield in one step without requiring lithium chloride and concentrated hydrochloric acid.

The present invention relates to 4,4′-dicarboxy-2,2′-bipyridine, ruthenium chloride and formula (1):
R-OH (1)
(In the formula, R is the same as above) The present invention relates to a method for producing a ruthenium complex (2), which comprises reacting an alcohol represented by the following formula (hereinafter referred to as alcohol (1)) at 85 ° C. or higher.

  According to the present invention, since the ruthenium complex (2) can be produced with a high yield in one step without using additives such as lithium chloride and concentrated hydrochloric acid, the industrial utility value is great.

Hereinafter, the present invention will be described in detail.
In formula (1) and formula (2), R represents a methyl group or an ethyl group. In the formula (2), R ¹ , R ² and R ³ are the same or different from each other and represent a hydrogen atom or the above R.

  In order to carry out the production method of the present invention, 4,4′-dicarboxy-2,2′-bipyridine, ruthenium chloride and alcohol (1) may be reacted at 85 ° C. or higher. In this way, the complex formation reaction and the esterification reaction proceed simultaneously, and the ruthenium complex (2) can be easily produced.

The target substance of the present invention is the following compound. 1) Monoester body [in formula (2), all of R ^{1 to} R ³ are hydrogen atoms] 2) Diester body [in formula (2), any two of R ^{1 to} R ³ are hydrogen atoms], 3 ) Triester form [in formula (2), any one of R ^{1 to} R ³ is a hydrogen atom] and 4) Tetraester form [in formula (2), all of R ^{1 to} R ³ are R]. In the production method of the present invention, it is generally obtained as a mixture of monoester, diester, triester and tetraester, but any target substance can be the main product depending on the degree of esterification. The degree of esterification is affected by the type of alcohol (1), raw material molar ratio, reaction temperature, reaction time, and the like.

  Specific examples of the ruthenium complex (2) include cis-dichloro- (4-carboxy-4′-methyloxycarbonyl-2,2′-bipyridine) (4,4′-dicarboxy-2, 2'-bipyridine) ruthenium (II), cis-dichloro- (4-carboxy-4'-ethyloxycarbonyl-2,2'-bipyridine) (4,4'-dicarboxy-2,2'-bipyridine) ruthenium (II) As a diester, cis-dichloro- (4,4′-dimethyloxycarbonyl-2,2′-bipyridine) (4,4′-dicarboxy-2,2′-bipyridine) ruthenium (II) Cis-Dichloro- (4,4′-diethyloxycarbonyl-2,2′-bipyridine) (4,4′-dicarboxy-2,2′-bipyridine) ruteniu (II), cis-dichloro-bis (4-carboxy-4'-methyloxycarbonyl-2,2'-bipyridine) ruthenium (II), cis-dichloro-bis (4-carboxy-4'-ethyloxycarbonyl- 2,2′-bipyridine) ruthenium (II), the triester form is cis-dichloro- (4-carboxy-4′-methyloxycarbonyl-2,2′-bipyridine) (4,4′-dimethyloxycarbonyl) -2,2'-bipyridine) ruthenium (II), cis-dichloro- (4-carboxy-4'-ethyloxycarbonyl-2,2'-bipyridine) (4,4'-diethyloxycarbonyl-2,2 ' -Bipyridine) ruthenium (II), tetraester form includes cis-dichloro-bis (4,4'-dimethyloxycarbo Le-2,2'-bipyridine) ruthenium (II), cis - dichloro - bis (4,4'-diethyl-butyloxycarbonyl-2,2'-bipyridine), and ruthenium (II) it is.

  In the production method of the present invention, ruthenium chloride does not need to be specially purified, and a commercially available product can be used as it is. Ruthenium chloride is generally marketed as a hydrate, and the hydrate is preferably used also in the method of the present invention.

  The amount of 4,4′-dicarboxy-2,2′-bipyridine used is usually 1.7 mol or more, preferably 1.8 to 3.0 mol, especially 1 mol per 1 mol of ruthenium atom in ruthenium chloride. Preferably it is 1.9-2.1 mol.

  In the production method of the present invention, the alcohol (1) is used as an esterifying agent and a solvent. Specifically, it is methanol or ethanol.

  Although alcohol (1) should just be used independently, it can be used even if it mixes methanol and ethanol. Moreover, as long as reaction is not inhibited, it can also react by coexisting organic solvents other than alcohol (1).

  The usage-amount of alcohol (1) is 5-100 weight part normally with respect to 1 weight part of 4,4'-dicarboxy-2,2'-bipyridine, Preferably it is 10-60 weight part. If the amount of alcohol (1) used is too large, it is not preferable because it is economically disadvantageous.

  The reaction temperature is usually 85 ° C. or higher, preferably 95 to 160 ° C. When the reaction temperature is less than 85 ° C., complex formation hardly proceeds and the yield of the ruthenium complex (2) becomes extremely low.

  In the method of the present invention, since the reaction is carried out at 85 ° C. or higher, a pressure resistant reactor is generally used. Although the mixing order of the raw materials is not particularly limited, since generally a pressure resistant reactor is used, ruthenium chloride, 4,4'-dicarboxy-2,2'-bipyridine and alcohol (1) are charged into the reactor at the same time.

  In the production method of the present invention, the reaction is preferably performed under light shielding. When the reaction is carried out without light shielding, a complex of trans conformation is by-produced. The light shielding method is not particularly limited as long as the reaction mixture in the reactor is not irradiated with light such as a fluorescent lamp or the sun. Moreover, it can perform normally in inert gas atmosphere, such as nitrogen gas and argon gas.

  After completion of the reaction, the ruthenium complex (2) can be obtained by performing desired separation operations such as filtration, concentration, extraction, and washing from the reaction mixture.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these. The esterification rate was calculated from the integral curve of ¹ H-NMR analysis using the following formula.

Example 1
In a 300 ml glass autoclave covered with aluminum foil and shielded from light, 3.97 g (16.0 mmol) of ruthenium (III) chloride hydrate (manufactured by Heraeus Co., Ltd .; ruthenium content 40.70%), 4,4′- 7.62 g (31.2 mmol) of dicarboxy-2,2′-bipyridine and 76.4 g of ethanol (boiling point 78 ° C.) were charged, purged with nitrogen, and reacted at a reaction temperature of 110 ° C. for 12 hours. After completion of the reaction, the reaction mixture was filtered at room temperature, and the residue was washed with methanol and dried to give cis-dichloro-bis (4,4′-diethyloxycarbonyl-2,2′-bipyridine) ruthenium (II ) Was obtained as a main component, 10.65 g (black green crystals, esterification rate 90%, yield 89.7%). The filtrate was concentrated, and the concentrated residue was washed with 42.3 g of 7.3% hydrochloric acid and dried to give cis-dichloro-bis (4,4′-diethyloxycarbonyl-2,2′-bipyridine. ) 0.95 g of ruthenium (II) (black green crystals, esterification rate 100%, yield 7.9%) was obtained.

Comparative Example 1
In a 100 ml glass reactor coated with aluminum foil and shielded from light, 0.50 g (2.0 mmol) of ruthenium (III) chloride hydrate (manufactured by Heraeus Co., Ltd .; ruthenium content 40.70%), 4,4′-di Carboxy-2,2′-bipyridine (0.95 g, 3.9 mmol) and ethanol (boiling point: 78 ° C.) 9.65 g were charged and reacted under reflux (reaction temperature: 77 ° C.) for 12 hours. After completion of the reaction, the reaction mixture was filtered at 65 ° C., and the residue was washed with ethanol. By concentrating the filtrate, 0.12 g of cis-dichloro-bis (4,4′-diethyloxycarbonyl-2,2′-bipyridine) ruthenium (II) (black green crystals, esterification rate 100%, yield) A rate of 8.0%) was obtained. The filter residue was dried to obtain 1.39 g of a gray solid, but this did not contain ruthenium complex (2).

Example 2
In a 300 ml glass autoclave covered with aluminum foil and shielded from light, 0.99 g (4.0 mmol) of ruthenium (III) chloride hydrate (manufactured by Heraeus; ruthenium content 40.70%), 4,4′- Dicarboxy-2,2′-bipyridine (1.91 g, 7.8 mmol) and methanol (boiling point: 64 ° C.) 95.3 g were charged, purged with nitrogen, and reacted at a reaction temperature of 110 ° C. for 12 hours. After completion of the reaction, the reaction mixture is filtered at room temperature, the residue is washed with methanol, dried and cis-dichloro-bis (4,4′-dimethyloxycarbonyl-2,2′-bipyridine) ruthenium (II). 2.00 g (black-green crystals, esterification rate 100%, yield 71.6%) was obtained. The filtrate was concentrated, and the concentrated residue was washed with 26.8 g of 7.3% hydrochloric acid and then dried to obtain cis-dichloro-bis (4,4′-dimethyloxycarbonyl-2,2′-bipyridine). 0.52 g of ruthenium (II) (black green crystals, esterification rate 100%, yield 18.6%) was obtained.

Claims (2)

4,4′-Dicarboxy-2,2′-bipyridine, ruthenium chloride and formula (1):
R-OH (1)
(Wherein R represents a methyl group or an ethyl group), the alcohol represented by the formula (2) is reacted at 85 ° C. or higher:

(Wherein R ¹ , R ² and R ³ represent a hydrogen atom or R. R is the same as defined above). The process according to claim 1, wherein the reaction temperature is 95 ° C to 160 ° C.