JP2008189551A - Method for producing binuclear metal complex - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a binuclear metal complex especially useful as a metal complex pigment capable of achieving a photoelectric transducer and a photochemical cell having high photoelectric conversion efficiency and durability. <P>SOLUTION: The method for producing the asymmetric binuclear metal complex represented by general formula, (L<SP>1</SP>)<SB>2</SB>M<SP>1</SP>(BL)M<SP>2</SP>(L<SP>2</SP>)<SB>2</SB>(X)<SB>n</SB>, includes reacting a mononuclear metal complex represented by the formula, (L<SP>1</SP>)<SB>2</SB>M<SP>1</SP>Cl<SB>2</SB>, with a mononuclear metal complex represented by the formula, (BL)M<SP>2</SP>(L<SP>2</SP>)<SB>2</SB>, in the presence of a base including lithium. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a novel binuclear metal complex.

  Furthermore, the present invention relates to a metal complex dye obtained by this production method, a photoelectric conversion element using an oxide semiconductor photosensitized by the metal complex dye, and a photochemical battery using the same.

  Solar cells are highly expected as a clean renewable energy source. Practical use of single-crystal silicon-based, polycrystalline silicon-based, amorphous silicon-based solar cells and solar cells composed of compounds such as cadmium telluride and indium copper selenide Research has been conducted with the aim of making it easier. However, in order to disseminate it as a household power source, many of the batteries that must be overcome, such as high manufacturing costs, difficulty in securing raw materials, recycling problems, and difficulty in increasing the area. I have a problem. Thus, solar cells using organic materials have been proposed with the aim of increasing the area and reducing the price, but all have a conversion efficiency of about 1%, which is far from practical use.

  Under such circumstances, in 1991, Gretzel et al. Disclosed a photoelectric conversion element and a solar cell using semiconductor fine particles sensitized with a dye in Nature, and materials and manufacturing techniques necessary for the production of the solar cell. (For example, Nature, Volume 353, page 737, 1991 (Non-Patent Document 1), JP-A-1-220380 (Patent Document 1), etc.). This battery is a wet solar cell using a porous titania thin film sensitized with a ruthenium dye as a working electrode. The advantage of this solar cell is that it can be used as an inexpensive photoelectric conversion element because it is not necessary to purify an inexpensive material with high purity, and further, the absorption of the dye used is broad, and over a wide visible light wavelength range. It can convert sunlight into electricity. However, further improvement in conversion efficiency is necessary for practical use, and development of a dye having a higher extinction coefficient and absorbing light up to a higher wavelength region is desired.

  JP 2003-261536 (Patent Document 2) by the present applicant discloses a dipyridyl ligand-containing metal mononuclear complex which is a metal complex dye useful as a photoelectric conversion element.

  In addition, the latest technology of dye-sensitized solar cells (CMC Co., Ltd., issued on May 25, 2001, page 117) (Non-Patent Document 2) discloses polynuclear β-diketonate complex dyes.

  In addition, Japanese Patent Application Laid-Open No. 2004-359677 (Patent Document 3) describes a plurality of metals and a plurality of coordinations as a novel multinuclear complex having an excellent photoelectric conversion function for extracting electrons by receiving the energy of actinic rays such as light. A binuclear complex having a coordination structure in which a bridging ligand (BL) having a conjugated group and a metal coordinated to a plurality of metals has a heteroconjugated ring and a coordination structure not having a heteroconjugated ring is disclosed.

  Furthermore, WO2006 / 038587 (Patent Document 4) discloses a binuclear metal complex having a coordination structure having a heteroconjugated ring as a metal complex dye that can provide a photoelectric conversion element having high photoelectric conversion efficiency. This binuclear metal complex is synthesized using a base containing sodium.

As a dye used for a photoelectric conversion element, a metal complex dye that has high photoelectric conversion efficiency and can realize a photoelectric conversion element having excellent durability is desired.
Japanese Patent Laid-Open No. 1-220380 JP 2003-261536 A Japanese Patent Application Laid-Open No. 2004-359677 WO2006 / 038587 Nature, 353, 737, 1991 The latest technology of dye-sensitized solar cells (CMC Corporation, issued on May 25, 2001, page 117)

  An object of the present invention is to provide a method for producing a binuclear metal complex particularly useful as a metal complex dye capable of realizing a photoelectric conversion element having high photoelectric conversion efficiency and durability and a photochemical battery.

  The present invention relates to the following matters.

1. General formula: (L ¹ ) ₂ M ¹ (BL) M ² (L ² ) ₂ (X) An asymmetric binuclear metal complex represented by _n (provided that M ¹ and M ² are transition metals and are the same But may be different, L ¹ and L ² is a capable of multidentate coordination chelate ligand, L ¹ and L ² are different, the two L ¹ is be different And two L ² may be different, and BL is a bridging ligand having at least two cyclic structures containing a hetero atom, and the coordination atom coordinated to M ¹ and M ² is Which is a heteroatom contained in the cyclic structure, X is a counter ion, n represents the number of counter ions necessary to neutralize the charge of the complex, and
A mononuclear metal complex represented by the formula: (L ¹ ) ₂ M ¹ Cl ₂ in the presence of a base (1) containing lithium (where M ¹ and L ¹ are as defined above) and a formula: (BL ) A production method comprising a step of reacting a mononuclear metal complex represented by M ² (L ² ) ₂ (wherein M ² , L ² and BL are as defined above).

  2. The production method according to 1 above, wherein the lithium-containing base (1) is lithium hydroxide and / or an alkoxide of lithium.

3. After reacting a mononuclear metal complex represented by the formula: (L ¹ ) ₂ M ¹ Cl ₂ and a mononuclear metal complex represented by the formula: (BL) M ² (L ² ) ₂ , an acid is added, or 1 or 2 above, which comprises a step of isolating a binuclear metal complex represented by the formula: (L ¹ ) ₂ M ¹ (BL) M ² (L ² ) ₂ (X) _n by adding a salt containing an acid and lithium The manufacturing method as described.

4). A mononuclear metal complex represented by the formula: (L ² ) ₂ M ² Cl ₂ in the presence of a base (2) containing lithium (provided that M ² and L ² are as defined above) and H ₂ (BL ) (Wherein BL is as defined above, and H ₂ (BL) represents a state in which two heteroatoms in BL are protonated), and the formula: (BL) M ² (L ² ) The manufacturing method in any one of said 1-3 which further has the process of synthesize | combining the mononuclear metal complex shown by ₂ .

  5. 5. The method according to 4 above, wherein the lithium-containing base (2) is a lithium alkoxide.

6). A mononuclear metal complex represented by the general formula: (BL) M ² (L ² ) ₂ (where M ² is a transition metal, L ² is a chelate-type ligand capable of multidentate coordination, The two L ² may be different, and BL is a bridging ligand having at least two cyclic structures containing a hetero atom, and the coordination atom coordinated to M ² is included in this cyclic structure. Is a heteroatom).
A mononuclear metal complex represented by the formula: (L ² ) ₂ M ² Cl ₂ in the presence of a base (2) containing lithium (provided that M ² and L ² are as defined above) and H ₂ (BL (Wherein BL is as defined above, and H ₂ (BL) represents a state in which two heteroatoms in BL are protonated).

7). An asymmetric binuclear metal complex represented by the general formula: (L ¹ ) ₂ M ¹ (BL) M ² (L ² ) ₂ (X) _n produced by the method according to any one of 1 to 5 above (provided that , M ¹ and M ² are transition metals which may be the same or different, L ¹ and L ² are chelate ligands capable of multidentate coordination, and L ¹ and L ² are The two L ¹ may be different, the two L ² may be different, and BL is a bridging ligand having at least two cyclic structures containing heteroatoms. The coordinating atoms coordinated with M ¹ and M ² are heteroatoms contained in this cyclic structure, X is a counter ion, and n is the number of counter ions necessary to neutralize the charge of the complex. Represents.)

8). An asymmetric binuclear metal complex represented by the general formula: (L ¹ ) ₂ M ¹ (BL) M ² (L ² ) ₂ (X) _n produced by the method according to any one of 1 to 5 above (provided that , M ¹ and M ² are transition metals which may be the same or different, L ¹ and L ² are chelate ligands capable of multidentate coordination, and L ¹ and L ² are Are different, the two L ¹ may be different, the two L ² may be different, X is a counter ion and n is necessary to neutralize the charge of the complex BL is a bridging ligand having at least two cyclic structures containing a heteroatom, and a heteroatom in which coordination atoms coordinated to M ¹ and M ² are included in this cyclic structure , and the have a ^{substituent L 1} is capable of attaching to a semiconductor particle, and mainly ^(L ₁₎ 2 M Metal complex dye, characterized in that it consists of LUMO is structured distributed.) To.

  9. 9. A photoelectric conversion element comprising semiconductor fine particles sensitized with the metal complex dye described in 8 above.

  10. 10. The photoelectric conversion element as described in 9 above, wherein the semiconductor fine particles are titanium oxide, zinc oxide, or tin oxide.

  11. 11. A photochemical battery using the photoelectric conversion element as described in 9 or 10 above.

In the present invention, a dinuclear metal complex (L ¹ ) ₂ M ¹ (BL) M ² (L ² ) ₂ (X) _n is synthesized using a base containing lithium. The photochemical battery using the binuclear metal complex dye produced according to the present invention has the same high photoelectric conversion as compared with the conventional one using a binuclear metal complex dye produced using a base containing sodium. Efficiency was obtained, and durability was further improved.

In the present invention, an asymmetric binuclear metal complex represented by the general formula: (L ¹ ) ₂ M ¹ (BL) M ² (L ² ) ₂ (X) _n is converted into two mononuclears as follows, for example. A metal complex (L ¹ ) ₂ M ¹ Cl ₂ and (BL) M ² (L ² ) ₂ are synthesized and synthesized by reacting them.

L ¹ is the following formula (L ¹ -1),

Ｍ^１がＲｕである単核金属錯体（Ｌ^１）_２Ｍ^１Ｃｌ_２（Ｍ^１Ｃ−１）は次の合成スキームに従って合成することができる。

A mononuclear metal complex (L ¹ ) ₂ M ¹ Cl ₂ (M ¹ C-1) in which M ¹ is Ru can be synthesized according to the following synthesis scheme.

上式において、Ｌ^１がカルボキシル基以外の置換基を有するもの、Ｍ^１がＲｕ以外の遷移金属であるものも同様にして合成することができる。

In the above formula, those in which L ¹ has a substituent other than a carboxyl group and those in which M ¹ is a transition metal other than Ru can be synthesized in the same manner.

L ¹ is the following formula (L ¹ -4),

Ｍ^１がＲｕである単核金属錯体（Ｌ^１）_２Ｍ^１Ｃｌ_２（Ｍ^１Ｃ−２）は次の合成スキームに従って合成することができる。

A mononuclear metal complex (L ¹ ) ₂ M ¹ Cl ₂ (M ¹ C-2) in which M ¹ is Ru can be synthesized according to the following synthesis scheme.

上式において、Ｌ^１がカルボキシル基以外の置換基を有するもの、Ｍ^１がＲｕ以外の遷移金属であるものも同様にして合成することができる。

In the above formula, those in which L ¹ has a substituent other than a carboxyl group and those in which M ¹ is a transition metal other than Ru can be synthesized in the same manner.

On the other hand, the mononuclear metal complex (BL) M ² (L ² ) ₂ can be synthesized according to the following synthesis scheme.

スキーム中のＨ_２ＢＬはＢＬ中の二つのヘテロ原子（窒素原子など）がプロトン化された状態を示す。

H ₂ BL in the scheme indicates a state in which two heteroatoms (such as a nitrogen atom) in BL are protonated.

In addition, BL is represented by formulas (BL-1) to (BL-4) (including those having a substituent), and L ² is represented by formulas (L ² -1) to (L ² ). -4) (including those having a substituent) can be synthesized according to this synthesis scheme. However, for those in which BL is represented by the formula (BL-1) (including those having a substituent), a reaction step with a base at the latter stage is unnecessary, and M ² (L ² ) ₂ Cl ₂ When BL is reacted, (BL) M ² (L ² ) ₂ is obtained.

  The base used in this reaction may be a base containing no sodium, for example, a base containing potassium, magnesium, calcium or iron, or an organic base, but a base containing lithium is preferred. Among these, lithium alkoxide is preferable, lithium methoxide, lithium ethoxide, and lithium-t-butoxide are more preferable, and lithium methoxide is particularly preferable. The amount of base used can be determined as appropriate.

The (L ¹ ) ₂ M ¹ Cl ₂ (M ¹ C) synthesized in this way and (BL) M ² (L ² ) ₂ (M ² C) are reacted according to the following synthetic scheme, and (L ¹ ) ₂ M ¹ (BL) M ² (L ² ) ₂ (X) _n can be synthesized.

この反応において使用する塩基はナトリウムを含まない塩基、例えばカリウム、マグネシウム、カルシウムまたは鉄を含む塩基、あるいは有機塩基であればよいが、リチウムを含む塩基が好ましい。中でも、リチウムの水酸化物およびリチウムのアルコキシドが好ましく、水酸化リチウム、リチウムメトキシド、リチウムエトキシド、リチウム−ｔ−ブトキシドがさらに好ましく、水酸化リチウムが特に好ましい。塩基の使用量は適宜決めることができる。

The base used in this reaction may be a base containing no sodium, for example, a base containing potassium, magnesium, calcium or iron, or an organic base, but a base containing lithium is preferred. Among these, lithium hydroxide and lithium alkoxide are preferable, lithium hydroxide, lithium methoxide, lithium ethoxide, and lithium-t-butoxide are more preferable, and lithium hydroxide is particularly preferable. The amount of base used can be determined as appropriate.

(L ¹ ) ₂ M ¹ Cl ₂ (M ¹ C) is reacted with (BL) M ² (L ² ) ₂ (M ² C) in the presence of a base, and then acid (HX) is added (L _{^{1) 2 M 1 (BL)}} M 2 (L 2) 2 (X) to the binuclear metal complex represented by _n isolated. A salt containing lithium (LiX) such as lithium nitrate may be added before or simultaneously with the addition of the acid.

  The metal complex of the present invention is a known method except that a base containing lithium is used, for example, WO 2006/038587, Inorganic Chemistry, Vol. 17, No. 9, pages 2660-2666, 1978, Journal of the. It can be produced with reference to methods cited in literature such as American Chemical Society, Vol. 115, pp. 6382-6390, 1993.

  Next, the binuclear metal complex produced by the present invention will be described.

In the asymmetric binuclear metal complex represented by the general formula: (L ¹ ) ₂ M ¹ (BL) M ² (L ² ) ₂ (X) _n , M ¹ and M ² are transition metals, Preferably, it is a transition metal of Group VIII to Group XI, specifically, ruthenium (Ru), osmium (Os), cobalt (Co), nickel (Ni), copper (Cu) or iron (Fe). preferable. Among these, ruthenium (Ru) and osmium (Os) are preferable, and ruthenium (Ru) is particularly preferable.

M ¹ and M ² may be the same metal or different metals.

L ¹ and L ² are chelate type ligands capable of multidentate coordination, preferably chelate type ligands capable of bidentate, tridentate or tetradentate coordination, more preferably chelate capable of bidentate coordination. Type ligand. Specific examples include derivatives such as 2,2′-bipyridine, 1,10-phenanthroline, 2- (2-pyridinyl) quinoline, or 2,2′-biquinoline. L ¹ and L ² are different. Further, the two L ¹ may be different, and the two L ² may be different.

When the binuclear metal complex of the present invention is a metal complex dye used for a photoelectric conversion element, L ¹ has at least one substituent that can be fixed to semiconductor fine particles.

Examples of the substituent that can be fixed to the semiconductor fine particles of L ¹ include a carboxyl group (—COOH), an amino group (—NH ₂ ), a hydroxyl group (—OH), a sulfate group (—SO ₃ H), and a phosphate group (—PO ₃ H ₂ ), nitro group (—NO ₂ ) and the like. Among these, a carboxyl group (—COOH) is preferable. The hydrogen of the carboxyl group may be exchanged with a cation such as quaternary ammonium such as tetrabutylammonium or an alkali metal ion such as sodium ion. Further, hydrogen may be eliminated.

Further, L ¹ may or may not have a substituent other than the substituent that can be fixed to the semiconductor fine particles. Examples of such a substituent include an alkyl group (such as a methyl group and an ethyl group) and an alkoxy group (such as a methoxy group and an ethoxy group).

When the binuclear metal complex of the present invention is a metal complex dye used for a photoelectric conversion element, L ¹ may be a ligand in which LUMO is distributed mainly in the (L ¹ ) ₂ M ¹ portion. preferable. “Mainly, LUMO is distributed in the (L ¹ ) ₂ M ¹ portion” means that more LUMO is distributed in the (L ¹ ) ₂ M ¹ portion than in the (L ² ) ₂ M ² portion. . By using a photoelectric conversion element including semiconductor fine particles sensitized by this binuclear metal complex mainly because (L ¹ ) ₂ M ¹ has a LUMO structure in which electrons are excited by light irradiation such as sunlight. When a photochemical battery is manufactured, smooth electron transfer from the electrolyte to the photoelectric conversion element (negative electrode) can be caused, and an efficient photochemical battery can be configured.

For the calculation of LUMO, the software used was Cerius ² or Material Studio. In this method, the structure of the metal complex was optimized by DFT (density functional method) using a DMol ³ module. The exchange correlation function at that time is not particularly limited, but the VWN method or the BLYP method is preferably used. The basis function is not particularly limited, but DNP is preferably used.

  The energy state calculation uses the obtained structure, and although there is no particular limitation on the exchange correlation function, BLYP and PBE are used, and the basis function system is not particularly limited, but DNP is preferably used.

L ¹ includes a ligand represented by the following formula (L ¹ -A).

式中、−ＣＯＯＨのＨは脱離していてもよく、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５及びＲ^６は水素原子、アルコキシ基または置換もしくは無置換の炭化水素基を表すか、または、これらの二つ以上が一緒になってそれらが結合する炭素原子と共に置換もしくは無置換の芳香族炭化水素環または置換もしくは無置換の脂肪族炭化水素環を形成している。

In the formula, H of —COOH may be eliminated, and R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ represent a hydrogen atom, an alkoxy group or a substituted or unsubstituted hydrocarbon group. Or two or more of these together form a substituted or unsubstituted aromatic hydrocarbon ring or a substituted or unsubstituted aliphatic hydrocarbon ring with the carbon atom to which they are attached.

R ^{1 to} R ⁶ are preferably a hydrogen atom, an alkyl group, or an alkoxy group, and more preferably a hydrogen atom or an alkyl group. As an alkyl group, a C6 or less thing is preferable and a methyl group and an ethyl group are more preferable. Moreover, as an alkoxy group, a C6 or less thing is preferable and a methoxy group and an ethoxy group are more preferable.

In addition, R ² and R ³ , R ⁴ and R ⁵ , R ¹ and R ⁶ are combined together and a carbon atom to which they are bonded together with a 6-membered aromatic hydrocarbon ring (which may have a substituent) It is also preferable to form. Examples of the substituent of the aromatic hydrocarbon ring include an alkyl group (such as a methyl group and an ethyl group) and an alkoxy group (such as a methoxy group and an ethoxy group).

R ^{1 to} R ⁶ are particularly preferably a hydrogen atom.

Specific examples of L ¹ include ligands represented by the following formulas (L ¹ -1) to (L ¹ -4), but the present invention is not limited to these.

２，２’−ビピリジン−４，４’−ジカルボン酸（Ｈ_２ｄｃｂｐｙ）

2,2′-bipyridine-4,4′-dicarboxylic acid (H ₂ dcbpy)

１，１０−フェナントロリン−４，７−ジカルボン酸（Ｈ_２ｄｃｐｈｅｎ）

1,10-phenanthroline-4,7-dicarboxylic acid (H ₂ dcphen)

２−（２−（４−カルボキシピリジル））−４−カルボキシキノリン（Ｈ_２ｄｃｐｑ）

2- (2-(4-carboxy-pyridyl)) - 4-carboxy quinoline _(H 2 _dcpq)

２，２’−ビキノリン−４，４’−ジカルボン酸（Ｈ_２ｄｃｂｉｑ）

但し、式（Ｌ^１−１）〜（Ｌ^１−４）中の複素環およびベンゼン環は置換基を有していてもよく、また、−ＣＯＯＨのＨは脱離していてもよい。置換基としては、メチル基、エチル基などの炭素数６以下のアルキル基、メトキシ基、エトキシ基などの炭素数６以下のアルコキシ基などが挙げられる。

2,2′-biquinoline-4,4′-dicarboxylic acid (H ₂ dcbiq)

However, the heterocyclic ring and the benzene ring in the formulas (L ¹ -1) to (L ¹ -4) may have a substituent, and H of —COOH may be eliminated. Examples of the substituent include an alkyl group having 6 or less carbon atoms such as a methyl group and an ethyl group, and an alkoxy group having 6 or less carbon atoms such as a methoxy group and an ethoxy group.

As described above, L ² is a chelate ligand capable of multidentate coordination, preferably a chelate ligand capable of bidentate, tridentate or tetradentate coordination, more preferably bidentate coordination. It is a chelate type ligand. Specific examples include derivatives such as 2,2′-bipyridine, 1,10-phenanthroline, 2- (2-pyridinyl) quinoline, or 2,2′-biquinoline.

L ² may or may not have a substituent. Examples of the substituent for L ² include an alkyl group (such as a methyl group and an ethyl group), an aryl group (such as a phenyl group and a tolyl group), an alkoxy group (such as a methoxy group and an ethoxy group), and a hydroxyl group (—OH). It is done. In particular, a group showing an electron donating property is preferable.

L ² includes a ligand represented by the following formula (L ² -A).

式中、Ｒ^１１、Ｒ^１２、Ｒ^１３、Ｒ^１４、Ｒ^１５、Ｒ^１６、Ｒ^１７及びＲ^１８は水素原子、アルコキシ基、水酸基または置換もしくは無置換の炭化水素基を表すか、または、これらの二つ以上が一緒になってそれらが結合する炭素原子と共に置換もしくは無置換の芳香族炭化水素環または置換もしくは無置換の脂肪族炭化水素環を形成している。

In the formula, R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ represent a hydrogen atom, an alkoxy group, a hydroxyl group or a substituted or unsubstituted hydrocarbon group, or these Two or more together form a substituted or unsubstituted aromatic hydrocarbon ring or a substituted or unsubstituted aliphatic hydrocarbon ring with the carbon atom to which they are attached.

R ^{11 to} R ¹⁸ are preferably a hydrogen atom, an alkyl group, or an alkoxy group, and more preferably a hydrogen atom or an alkyl group. As an alkyl group, a C6 or less thing is preferable and a methyl group and an ethyl group are more preferable. Moreover, as an alkoxy group, a C6 or less thing is preferable and a methoxy group and an ethoxy group are more preferable.

Further, (which may have a substituent) two adjacent, or R ¹¹ and R ¹⁸ together aromatic 6-membered together with the carbon atoms to which they are bonded hydrocarbon ring R ¹¹ to R ¹⁸ It is also preferable to form. Examples of the substituent of the aromatic hydrocarbon ring include an alkyl group (such as a methyl group and an ethyl group) and an alkoxy group (such as a methoxy group and an ethoxy group).

R ^{11 to} R ¹⁸ are particularly preferably a hydrogen atom or a methyl group. R ¹¹ and R ¹⁸ are combined to form a 6-membered aromatic hydrocarbon ring (which may have a substituent such as a methyl group) together with the carbon atom to which they are bonded, and R ¹² It is particularly preferred that R ¹⁷ is a hydrogen atom or a methyl group, more preferably a hydrogen atom.

Specific examples of L ² include ligands represented by the following formulas (L ² -1) to (L ² -4), but the present invention is not limited to these.

２，２’−ビピリジン（ｂｐｙ）

2,2'-bipyridine (bpy)

１，１０−フェナントロリン（ｐｈｅｎ）

1,10-phenanthroline (phen)

２−（２−ピリジニル）キノリン（ｐｑ）

2- (2-Pyridinyl) quinoline (pq)

２，２’−ビキノリン（ｂｉｑ）

但し、式（Ｌ^２−１）〜（Ｌ^２−４）中の複素環およびベンゼン環は置換基を有していてもよい。置換基としては、炭素数６以下のアルキル基、炭素数６以下のアルコキシ基、メチル基などの置換基を有していてもよいフェニル基、水酸基などが挙げられる。

2,2'-biquinoline (biq)

However, the heterocyclic ring and the benzene ring in the formulas (L ² -1) to (L ² -4) may have a substituent. Examples of the substituent include an alkyl group having 6 or less carbon atoms, an alkoxy group having 6 or less carbon atoms, a phenyl group which may have a substituent such as a methyl group, and a hydroxyl group.

BL is a bridging ligand and has a cyclic structure containing a hetero atom. And the hetero atom contained in this cyclic structure (heteroconjugate ring) is a coordination atom coordinated to M ¹ and M ² . Heteroatoms include nitrogen, oxygen, sulfur, phosphorus and the like.

  BL is preferably a tetradentate ligand, more preferably anionic. Further, BL may or may not have a substituent on the cyclic structure (heteroconjugate ring).

  Examples of BL include those represented by the following formula (BL-A).

式中、Ｒ^３１、Ｒ^３２及びＲ^３３は水素原子または置換もしくは無置換の炭化水素基を表すか、または、これらの二つ以上が一緒になってそれらが結合する炭素原子と共に置換もしくは無置換の芳香族炭化水素環または置換もしくは無置換の脂肪族炭化水素環を形成しており、Ｒ^３４、Ｒ^３５及びＲ^３６は水素原子または置換もしくは無置換の炭化水素基を表すか、または、これらの二つ以上が一緒になってそれらが結合する炭素原子と共に置換もしくは無置換の芳香族炭化水素環または置換もしくは無置換の脂肪族炭化水素環を形成している。

In the formula, R ³¹ , R ³² and R ³³ represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group, or two or more of these together are substituted or unsubstituted with the carbon atom to which they are bonded. An aromatic hydrocarbon ring or a substituted or unsubstituted aliphatic hydrocarbon ring, and R ³⁴ , R ³⁵ and R ³⁶ represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group, or Two or more together form a substituted or unsubstituted aromatic hydrocarbon ring or a substituted or unsubstituted aliphatic hydrocarbon ring with the carbon atom to which they are attached.

R ^{31 to} R ³⁶ are preferably a hydrogen atom, an alkyl group, or an alkoxy group, and more preferably a hydrogen atom or an alkyl group. As an alkyl group, a C6 or less thing is preferable and a methyl group and an ethyl group are more preferable. Moreover, as an alkoxy group, a C6 or less thing is preferable and a methoxy group and an ethoxy group are more preferable.

It is also preferable that two adjacent R ^{31 to} R ³⁶ are joined together to form a 6-membered aromatic hydrocarbon ring (which may have a substituent) together with the carbon atom to which they are bonded. . Examples of the substituent of the aromatic hydrocarbon ring include an alkyl group (such as a methyl group and an ethyl group) and an alkoxy group (such as a methoxy group and an ethoxy group).

R ^{31 to} R ³⁶ are particularly preferably a hydrogen atom or a methyl group, and R ^{31 to} R ³⁶ are more preferably a hydrogen atom.

  Moreover, as BL, what is represented by the following Formula (BL-B) is also mentioned.

式中、Ｒ^４１及びＲ^４２は水素原子または置換もしくは無置換の炭化水素基を表すか、または、これらが一緒になってそれらが結合する炭素原子と共に置換もしくは無置換の芳香族炭化水素環または置換もしくは無置換の脂肪族炭化水素環を形成しており、Ｒ^４３及びＲ^４４は水素原子または置換もしくは無置換の炭化水素基を表すか、または、これらが一緒になってそれらが結合する炭素原子と共に置換もしくは無置換の芳香族炭化水素環または置換もしくは無置換の脂肪族炭化水素環を形成している。

In the formula, R ⁴¹ and R ⁴² represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group, or a substituted or unsubstituted aromatic hydrocarbon ring together with a carbon atom to which they are bonded together, or Forming a substituted or unsubstituted aliphatic hydrocarbon ring, wherein R ⁴³ and R ⁴⁴ represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group, or the carbon to which they are bonded together; A substituted or unsubstituted aromatic hydrocarbon ring or a substituted or unsubstituted aliphatic hydrocarbon ring is formed together with the atoms.

R ^{41 to} R ⁴⁴ are preferably a hydrogen atom, an alkyl group, or an alkoxy group, and more preferably a hydrogen atom or an alkyl group. As an alkyl group, a C6 or less thing is preferable and a methyl group and an ethyl group are more preferable. Moreover, as an alkoxy group, a C6 or less thing is preferable and a methoxy group and an ethoxy group are more preferable.

R ⁴¹ and R ⁴² , R ⁴³ and R ⁴⁴ together form a 6-membered aromatic hydrocarbon ring (which may have a substituent) together with the carbon atom to which they are bonded. Is also preferable. Examples of the substituent of the aromatic hydrocarbon ring include an alkyl group (such as a methyl group and an ethyl group) and an alkoxy group (such as a methoxy group and an ethoxy group).

R ^{41 to} R ⁴⁴ are particularly preferably a hydrogen atom or a methyl group, and R ^{41 to} R ⁴⁴ are more preferably a hydrogen atom. R ⁴¹ and R ⁴² , R ⁴³ and R ⁴⁴ together form a 6-membered aromatic hydrocarbon ring (which may have a substituent such as a methyl group) together with the carbon atom to which they are bonded. It is also particularly preferable.

  Among those represented by the above formula (BL-B), those represented by the following formula (BL-C) are preferable.

式中、Ｒ^５１、Ｒ^５２、Ｒ^５３及びＲ^５４は水素原子または置換もしくは無置換の炭化水素基を表すか、または、これらの二つ以上が一緒になってそれらが結合する炭素原子と共に置換もしくは無置換の芳香族炭化水素環または置換もしくは無置換の脂肪族炭化水素環を形成しており、Ｒ^５５、Ｒ^５６、Ｒ^５７及びＲ^５８は水素原子または置換もしくは無置換の炭化水素基を表すか、または、これらの二つ以上が一緒になってそれらが結合する炭素原子と共に置換もしくは無置換の芳香族炭化水素環または置換もしくは無置換の脂肪族炭化水素環を形成している。

In the formula, R ⁵¹ , R ⁵² , R ⁵³ and R ⁵⁴ represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group, or two or more of these together are substituted with a carbon atom to which they are bonded. Or an unsubstituted aromatic hydrocarbon ring or a substituted or unsubstituted aliphatic hydrocarbon ring, and R ⁵⁵ , R ⁵⁶ , R ⁵⁷ and R ⁵⁸ are each a hydrogen atom or a substituted or unsubstituted hydrocarbon group. Or two or more of these together form a substituted or unsubstituted aromatic hydrocarbon ring or a substituted or unsubstituted aliphatic hydrocarbon ring with the carbon atom to which they are attached.

R ^{51 to} R ⁵⁸ are preferably a hydrogen atom, an alkyl group, or an alkoxy group, and more preferably a hydrogen atom or an alkyl group. As an alkyl group, a C6 or less thing is preferable and a methyl group and an ethyl group are more preferable. Moreover, as an alkoxy group, a C6 or less thing is preferable and a methoxy group and an ethoxy group are more preferable.

It is also preferable that two adjacent R ^{51 to} R ⁵⁸ are joined together to form a 6-membered aromatic hydrocarbon ring (which may have a substituent) together with the carbon atom to which they are bonded. . Examples of the substituent of the aromatic hydrocarbon ring include an alkyl group (such as a methyl group and an ethyl group) and an alkoxy group (such as a methoxy group and an ethoxy group).

R ^{51 to} R ⁵⁸ are particularly preferably a hydrogen atom or a methyl group, and R ^{51 to} R ⁵⁸ are more preferably a hydrogen atom.

  Specific examples of BL include those represented by the following formulas (BL-1) to (BL-4), but the present invention is not limited to these.

２，２’−ビピリミジン（ｂｐｍ）

2,2'-bipyrimidine (bpm)

テトラチアフルバレン（ＴＴＦ）

Tetrathiafulvalene (TTF)

２，２’−ビイミダゾラト（ＢｉＩｍ）

2,2'-biimidazolate (BiIm)

２，２’−ビベンズイミダゾラト（ＢｉＢｚＩｍ）

但し、式（ＢＬ−１）〜（ＢＬ−４）中の複素環およびベンゼン環は置換基を有していてもよい。置換基としては、炭素数６以下のアルキル基、炭素数６以下のアルコキシ基などが挙げられ、また、式（ＢＬ−４）中のベンゼン環上の隣接する二つの炭素原子が一緒になって新たなベンゼン環（置換基を有していてもよい）を形成していてもよい。

2,2'-bibenzimidazolate (BiBzIm)

However, the heterocyclic ring and the benzene ring in formulas (BL-1) to (BL-4) may have a substituent. Examples of the substituent include an alkyl group having 6 or less carbon atoms and an alkoxy group having 6 or less carbon atoms, and two adjacent carbon atoms on the benzene ring in the formula (BL-4) are joined together. A new benzene ring (which may have a substituent) may be formed.

  In the case of a metal complex dye used for a photoelectric conversion element, BL is preferably a ligand represented by the above formula (BL-3) or (BL-4).

Further, (L ¹ ) ₂ M ¹ (BL) M ² (L ² ) ₂ (X) _n may contain water or an organic solvent as a crystal solvent. Examples of the organic solvent include DMSO, acetonitrile, DMF, DMAC, methanol and the like. The number of crystal solvents is not particularly specified.

X is a counter ion, and if the complex [(L ¹ ) ₂ M ¹ (BL) M ² (L ² ) ₂ ] is a cation, the counter ion is an anion, and the complex [(L ¹ ) ₂ M ¹ (BL) M ^{If 2} (L ² ) ₂ ] is an anion, the counter ion is a cation. Here, n represents the number of counter ions necessary to neutralize the charge of the complex.

  As specific examples of X, when the counter ion is an anion, hexafluorophosphate ion, perchlorate ion, tetraphenylborate ion, tetrafluoroborate ion, trifluoromethanesulfonate ion, thiocyanate ion, sulfate ion, nitric acid Ions, and halide ions such as chloride ions and iodide ions.

  Specific examples of X include, when the counter ion is a cation, ammonium metal, tetrabutylammonium ion, alkali metal ions such as sodium ion, and proton.

As the metal complex dye, in particular, L ¹ is a ligand represented by the above formula (L ¹ -1) ( ^one from which H of —COOH is eliminated, a heterocyclic ring and a benzene ring further having a substituent. And L ² is a ligand represented by the above formula (L ² -1) or (L ² -2) (a heterocycle and a benzene ring having a substituent) BL is a ligand represented by the above formula (BL-3) or (BL-4) (including those having a heterocyclic ring and a benzene ring having a substituent), and M ¹ And M ² is preferably ruthenium (Ru), osmium (Os), cobalt (Co), nickel (Ni), copper (Cu) or iron (Fe).

Specific examples of the asymmetric binuclear metal complex represented by (L ¹ ) ₂ M ¹ (BL) M ² (L ² ) ₂ (X) _n of the present invention include the following formulas (D-1) to (D- Although what is represented by 16) is mentioned, this invention is not limited to these.

［（Ｈ_２ｄｃｂｐｙ）_２Ｒｕ（ＢｉＩｍ）Ｒｕ（ｂｐｙ）_２］（ＣｌＯ_４）_２

[(H ₂ dcbpy) ₂ Ru (BiIm) Ru (bpy) ₂ ] (ClO ₄ ) ₂

［（Ｈ_２ｄｃｂｐｙ）（Ｈｄｃｂｐｙ）Ｒｕ（ＢｉＩｍ）Ｒｕ（ｂｐｙ）_２］（ＰＦ_６）

[(H ₂ dcbpy) (Hdcbpy) Ru (BiIm) Ru (bpy) ₂ ] (PF ₆ )

［（Ｈ_２ｄｃｂｉｑ）（Ｈｄｃｂｉｑ）Ｒｕ（ＢｉＩｍ）Ｒｕ（ｂｐｙ）_２］（ＰＦ_６）

[(H ₂ dcbiq) (Hdcbiq) Ru (BiIm) Ru (bpy) ₂ ] (PF ₆ )

［（Ｈ_２ｄｃｂｐｙ）（Ｈｄｃｂｐｙ）Ｒｕ（ＢｉＢｚＩｍ）Ｒｕ（ｂｐｙ）_２］（ＰＦ_６）

[(H ₂ dcbpy) (Hdcbpy) Ru (BiBzIm) Ru (bpy) ₂ ] (PF ₆ )

［（Ｈ_２ｄｃｂｐｙ）（Ｈｄｃｂｐｙ）Ｒｕ（ＢｉＢｚＩｍ）Ｒｕ（ｂｐｙ）_２］（ＢＦ_４）

[(H ₂ dcbpy) (Hdcbpy) Ru (BiBzIm) Ru (bpy) ₂ ] (BF ₄ )

［（Ｈ_２ｄｃｂｐｙ）（Ｈｄｃｂｐｙ）Ｒｕ（ＢｉＢｚＩｍ）Ｒｕ（ｂｐｙ）_２］（ＢＰｈ_４）

[(H ₂ dcbpy) (Hdcbpy) Ru (BiBzIm) Ru (bpy) ₂ ] (BPh ₄ )

［（Ｈ_２ｄｃｂｐｙ）（Ｈｄｃｂｐｙ）Ｒｕ（ＢｉＢｚＩｍ）Ｒｕ（ｂｐｙ）_２］（ＯＳＯ_２ＣＦ_３）

[(H ₂ dcbpy) (Hdcbpy) Ru (BiBzIm) Ru (bpy) ₂ ] (OSO ₂ CF ₃ )

［（Ｈ_２ｄｃｂｐｙ）（Ｈｄｃｂｐｙ）Ｒｕ（ＢｉＢｚＩｍ）Ｒｕ（ｂｐｙ）_２］（ＣｌＯ_４）

[(H ₂ dcbpy) (Hdcbpy) Ru (BiBzIm) Ru (bpy) ₂ ] (ClO ₄ )

［（Ｈ_２ｄｃｂｐｙ）（Ｈｄｃｂｐｙ）Ｒｕ（ＢｉＢｚＩｍ）Ｒｕ（ｂｐｙ）_２］（ＮＯ_３）

[(H ₂ dcbpy) (Hdcbpy) Ru (BiBzIm) Ru (bpy) ₂ ] (NO ₃ )

［（Ｈ_２ｄｃｂｐｙ）（Ｈｄｃｂｐｙ）Ｒｕ（ＢｉＢｚＩｍ）Ｒｕ（ｂｐｙ）_２］（Ｉ）

[(H ₂ dcbpy) (Hdcbpy) Ru (BiBzIm) Ru (bpy) ₂ ] (I)

［（Ｈ_２ｄｃｂｐｙ）（Ｈｄｃｂｐｙ）Ｒｕ（ＢｉＢｚＩｍ）Ｒｕ（ｐｈｅｎ）_２］（ＰＦ_６）

[(H ₂ dcbpy) (Hdcbpy) Ru (BiBzIm) Ru (phen) ₂ ] (PF ₆ )

［（Ｈ_２ｄｃｂｐｙ）（Ｈｄｃｂｐｙ）Ｒｕ（ＢｉＢｚＩｍ）Ｒｕ（ｂｉｑ）_２］（ＰＦ_６）

[(H ₂ dcbpy) (Hdcbpy) Ru (BiBzIm) Ru (biq) ₂ ] (PF ₆ )

［（Ｈ_２ｄｃｂｐｙ）（Ｈｄｃｂｐｙ）Ｒｕ（ＢｉＢｚＩｍ）Ｒｕ（ｄｍｂｐｙ）_２］（ＰＦ_６）

[(H ₂ dcbpy) (Hdcbpy) Ru (BiBzIm) Ru (dmbpy) ₂ ] (PF ₆ )

［（Ｈ_２ｄｃｂｐｙ）（Ｈｄｃｂｐｙ）Ｒｕ（ＴＭＢｉＢｚＩｍ）Ｒｕ（ｂｐｙ）_２］（ＰＦ_６）

[(H ₂ dcbpy) (Hdcbpy) Ru (TMBiBzIm) Ru (bpy) ₂ ] (PF ₆ )

［（Ｈ_２ｄｃｂｐｙ）（Ｈｄｃｂｐｙ）Ｒｕ（ＢｉＢｚＩｍ）Ｏｓ（ｂｐｙ）_２］（ＰＦ_６）

[(H ₂ dcbpy) (Hdcbpy) Ru (BiBzIm) Os (bpy) ₂ ] (PF ₆ )

［（Ｈｄｃｂｐｙ）_２Ｒｕ（ｂｐｍ）Ｒｕ（ｂｐｙ）_２］（ＰＦ₆）_２

上記の金属錯体は、金属錯体色素として用いることができ、金属錯体色素により増感された半導体微粒子を用いて、光化学電池を製造することができる。

[(Hdcbpy) ₂ Ru (bpm) Ru (bpy) ₂ ] (PF ₆ ) ₂

The above metal complex can be used as a metal complex dye, and a photochemical battery can be produced using semiconductor fine particles sensitized with the metal complex dye.

  The photoelectric conversion element of this invention contains the semiconductor fine particle sensitized with said metal complex pigment | dye. More specifically, the semiconductor fine particles sensitized with the metal complex dye are fixed on the electrode.

  The conductive electrode is preferably a transparent electrode formed on a transparent substrate. Examples of the conductive agent include metals such as gold, silver, copper, platinum, and palladium, indium oxide compounds typified by tin-doped indium oxide (ITO), and oxidation typified by fluorine-doped tin oxide (FTO). Examples thereof include tin compounds and zinc oxide compounds.

  Examples of the semiconductor fine particles include titanium oxide, zinc oxide, and tin oxide. In addition, indium oxide, niobium oxide, tungsten oxide, vanadium oxide, composite oxide semiconductors such as strontium titanate, calcium titanate, barium titanate, potassium niobate, cadmium or bismuth sulfide, cadmium selenide or tellurium And gallium phosphide or arsenide. As the semiconductor fine particles, oxides are preferable, and titanium oxide, zinc oxide, or tin oxide, and a mixture containing any one or more of these are particularly preferable.

  The primary particle diameter of the semiconductor fine particles is not particularly limited, but is usually 1 to 5000 nm, preferably 2 to 500 nm, and particularly preferably 5 to 300 nm.

  The photochemical cell of the present invention uses the above photoelectric conversion element. More specifically, the photoelectric conversion element of the present invention and a counter electrode are provided as electrodes, and an electrolyte layer is provided therebetween. At least one of the electrode and the counter electrode used in the photoelectric conversion element of the present invention is a transparent electrode.

  The counter electrode functions as a positive electrode when combined with a photoelectric conversion element to form a photochemical battery. As the counter electrode, a substrate having a conductive layer can be used as in the case of the conductive electrode. However, if the metal plate itself is used, the substrate is not necessarily required. Examples of the conductive agent used for the counter electrode include metals such as platinum and carbon, and conductive metal oxides such as tin oxide doped with fluorine.

  The electrolyte (redox couple) is not particularly limited, and any known one can be used. For example, iodine and iodide (for example, metal iodides such as lithium iodide and potassium iodide, or quaternary ammonium compounds such as tetrabutylammonium iodide, tetrapropylammonium iodide, pyridinium iodide, imidazolium iodide) Iodide), bromine and bromide, chlorine and chloride, alkyl viologen and its reduced form, quinone / hydroquinone, iron (II) ion / iron (III) ion, copper (I) ion / Transition metal ion pairs such as copper (II) ion, manganese (II) ion / manganese (III) ion, cobalt ion (II) / cobalt ion (III), ferrocyan / ferricyan, cobalt tetrachloride (II) / four Cobalt (III) chloride, cobalt (II) tetrabromide / four odors Cobalt (III), iridium hexachloride (II) / iridium hexachloride (III), ruthenium hexacyanide (II) / ruthenium hexacyanide (III), rhodium hexachloride (II) / rhodium hexachloride (III), six Rhenium chloride (III) / rhenium chloride (IV), rhenium hexachloride (IV) / rhenium hexachloride (V), osmium hexachloride (III) / osmium hexachloride (IV), osmium hexachloride (IV) / hexachloride It is formed by a combination of complex ions such as osmium (V), transition metals such as cobalt, iron, ruthenium, manganese, nickel, rhenium and biconjugated and derivatives thereof, terpyridine and derivatives thereof, and heteroconjugated rings such as phenanthroline and derivatives thereof Complexes, ferrocene / ferrocenium ions, cobalt On / cobalt-ion-, ruthenocene / lutein placed um cyclopentadiene and its derivatives and metal complexes such as an ion, porphyrin compounds and the like can be used. A preferable electrolyte is an electrolyte in which iodine and lithium iodide or iodide of a quaternary ammonium compound are combined. The state of the electrolyte may be a liquid dissolved in an organic solvent, a molten salt, a so-called gel electrolyte immersed in a polymer matrix, or a solid electrolyte.

  The photochemical cell of the present invention can be produced by a conventionally applied method.

  For example, a semiconductor fine particle paste such as an oxide is applied on a transparent electrode and heated and fired to produce a thin film of semiconductor fine particles. When the thin film of semiconductor fine particles is titania, it is fired at a temperature of 450 ° C. and a reaction time of 30 minutes. The transparent electrode with the thin film is immersed in a dye solution, and the photoelectric conversion element is manufactured by supporting the dye. Furthermore, the photochemical cell of the present invention can be manufactured by combining this photoelectric conversion element with a transparent electrode on which platinum or carbon is deposited as a counter electrode, and inserting an electrolyte solution therebetween.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

(Example 1)
Synthesis of Binuclear Metal Complex Dye [(H ₂ dcbpy) (Hdcbpy) Ru (BiBzIm) Ru (bpy) ₂ ] (NO ₃ ) (D-9) Synthesis of mononuclear metal complex (H ₂ dcbpy) ₂ RuCl ₂ (M ¹ C-1) In a 500 ml three-necked flask under a nitrogen atmosphere, commercially available RuCl ₃ .3H ₂ O (2.53 g, 9.68 mmol), H ₂ dcbpy (4.50 g, 18.4 mmol) and 300 ml of N, N-dimethylformamide were added and refluxed for 45 minutes under microwave irradiation of 2.45 GHz. The mixture was allowed to cool and then filtered, and the obtained filtrate was dried under reduced pressure. The obtained residue was washed with acetone / diethyl ether (1: 4), 300 ml of 2 mol / l hydrochloric acid was added, ultrasonic stirring was continued for 20 minutes, and further, stirring was stopped for 2 hours. After completion of the stirring, the insoluble material was collected by filtration and washed with 2 mol / l hydrochloric acid, acetone / diethyl ether (1: 4) and diethyl ether. After vacuum drying, 5.75 g of M ¹ C-1 was obtained (yield 85%).

２．単核金属錯体（ＢｉＢｚＩｍ）Ｒｕ（ｂｐｙ）_２（Ｍ^２Ｃ−２）の合成
窒素雰囲気下、３００ｍｌ三口フラスコに、Ｒｕ（ｂｐｙ）_２Ｃｌ_２（４．０２ｇ，７．７ｍｍｏｌ）、Ｉｎｏｒｇ．Ｃｈｅｍ．，３４，５９７９（１９９５）を参照して合成した２，２’−ビベンズイミダゾール（ＢｉＢｚＩｍＨ_２）（２．１８ｇ，９．３ｍｍｏｌ）、およびエチレングリコールを１００ｍｌ加え、２．４５ＧＨｚのマイクロ波照射下５分間還流した。放冷後、１０％のリチウムメトキシドメタノール溶液を３５ｍｌ加え、６０℃で１０分間２．４５ＧＨｚのマイクロ波を照射した。放冷後、２００ｍｌの水を加え、攪拌し、析出物をろ過した。析出物を水、冷メタノール、およびジエチルエーテルで洗浄、真空乾燥後、Ｍ^２Ｃ−２を５．７７０８ｇ得た。さらに、この析出物５．７７ｇを窒素下でメタノール２００ｍｌに加え、さらにここへ１０％のリチウムメトキシドメタノール溶液を１０ｍｌ加え、１時間還流した。放冷後、析出物をろ過し、冷メタノール、水、およびジエチルエーテルで洗浄、真空乾燥後、Ｍ^２Ｃ−２を５．０２ｇ得た（収率９５％）。

2. Synthesis of mononuclear metal complex (BiBzIm) Ru (bpy) ₂ (M ² C-2) In a nitrogen atmosphere, Ru (bpy) ₂ Cl ₂ (4.02 g, 7.7 mmol), Inorg. Chem. , 34, 5979 (1995), and 100 ml of 2,2′-bibenzimidazole (BiBzImH ₂ ) (2.18 g, 9.3 mmol) and ethylene glycol were added under microwave irradiation at 2.45 GHz. Refluxed for 5 minutes. After allowing to cool, 35 ml of a 10% lithium methoxide methanol solution was added and irradiated with a microwave of 2.45 GHz at 60 ° C. for 10 minutes. After allowing to cool, 200 ml of water was added and stirred, and the precipitate was filtered. The precipitate was washed with water, cold methanol, and diethyl ether, and dried under vacuum to obtain 5.7708 g of M ² C-2. Further, 5.77 g of this precipitate was added to 200 ml of methanol under nitrogen, and further 10 ml of a 10% lithium methoxide methanol solution was added thereto and refluxed for 1 hour. After allowing to cool, the precipitate was filtered, washed with cold methanol, water and diethyl ether, and vacuum dried to obtain 5.02 g of M ² C-2 (yield 95%).

３．Ｄ−９の合成
窒素雰囲気下、３００ｍｌ三口フラスコに、Ｍ^１Ｃ−１（０．６０４ｇ，０．８７ｍｍｏｌ）、およびエタノール／水（１：１）を１００ｍｌ加え、１ｍｏｌ／ｌ水酸化リチウム水溶液を３．５ｍｌ滴下し溶解させた。この溶液にＭ^２Ｃ−２（０．６２４ｇ，０．９２ｍｍｏｌ）を加え、２．４５ＧＨｚのマイクロ波照射下３０分間還流した。放冷後、少量の不溶解物をろ別後、ろ液のエタノールを減圧留去した。得られた懸濁液をろ過し、ろ液に硝酸リチウム（０．６１５ｇ、８．９２ｍｍｏｌ）を加え、さらに０．５ｍｏｌ／ｌ硝酸水溶液をｐＨ２．５になるまで滴下した。析出した錯体をろ取し、ｐＨ２．５硝酸水溶液、アセトン／ジエチルエーテル（１：４）、およびジエチルエーテルで洗浄した。真空乾燥後、Ｄ−９を１．０１０ｇ得た（収率８７％）。

3. Synthesis of D-9 Under a nitrogen atmosphere, 100 ml of M ¹ C-1 (0.604 g, 0.87 mmol) and ethanol / water (1: 1) was added to a 300 ml three-necked flask, and a 1 mol / l lithium hydroxide aqueous solution was added. 3.5 ml was dropped and dissolved. M ² C-2 (0.624 g, 0.92 mmol) was added to this solution and refluxed for 30 minutes under microwave irradiation at 2.45 GHz. After allowing to cool, a small amount of insoluble matter was filtered off, and ethanol in the filtrate was distilled off under reduced pressure. The obtained suspension was filtered, lithium nitrate (0.615 g, 8.92 mmol) was added to the filtrate, and a 0.5 mol / l nitric acid aqueous solution was further added dropwise until the pH reached 2.5. The precipitated complex was collected by filtration and washed with a pH 2.5 aqueous nitric acid solution, acetone / diethyl ether (1: 4), and diethyl ether. After vacuum drying, 1.010 g of D-9 was obtained (yield 87%).

(Example 2)
1. Production of porous titania electrode (Production of porous titania electrode)
The catalyst chemical titania paste PST-18NR was applied to the transparent layer, and PST-400C was applied to the diffusion layer, and applied onto a transparent conductive glass electrode manufactured by Asahi Glass Co., Ltd. using a screen printer. The obtained film was aged at 25 ° C. in an atmosphere of 60% for 5 minutes, and the aged film was baked at 450 ° C. for 30 minutes. The same operation was repeated on the cooled membrane until a predetermined thickness was obtained, thereby producing a 16 mm ² porous titania electrode.

2. Preparation of Porous Titania Electrode Adsorbed with Dye Porous titania electrode is immersed in saturated dye solution of D-9 t-butanol / acetonitrile 1: 1 mixed solvent at 30 ° C. for 40 hours, dried to adsorb dye A porous titania electrode was obtained.

3. Production of Photochemical Battery The dye-adsorbed porous titania electrode obtained as described above and a platinum plate (counter electrode) were superposed. Next, a photochemical battery was fabricated by impregnating the electrolyte solution into the gap between the two electrodes using a capillary phenomenon.

4). Durability Evaluation The obtained photochemical battery was allowed to stand in a dark place at 85 ° C. for a predetermined time and then returned to room temperature. The photoelectric conversion efficiency (η) was simulated at 100 mW / cm ² using a solar simulator manufactured by Eihiro Seiki Co., Ltd. Sunlight was irradiated and measured. FIG. 1 shows the change in photoelectric conversion efficiency depending on the time left in a dark place at 85 ° C.

(Comparative Example 1)
A sodium methoxide methanol solution was used instead of the lithium methoxide methanol solution in the synthesis of M ² C-2, a sodium hydroxide aqueous solution was used in place of the lithium hydroxide aqueous solution in the synthesis of D-9, and sodium nitrate was substituted in place of lithium nitrate. A binuclear metal complex dye (D-9) was produced in the same manner as in Example 1 except that was used. And using this pigment | dye, the photochemical battery was produced like Example 2 and durability was evaluated. The result is shown in FIG.

  As is clear from FIG. 1, the durability of the photochemical battery using the binuclear metal complex dye of the present invention was improved compared to that using a dye synthesized using a base containing sodium.

  As described above, according to the present invention, a metal complex dye capable of realizing a photochemical battery having high photoelectric conversion efficiency and durability can be produced.

FIG. 1 is a graph showing the photoelectric conversion efficiency of the photochemical batteries obtained in Example 2 and Comparative Example 1 after standing for a predetermined time in a dark place at 85 ° C.

Claims (11)

General formula: (L ¹ ) ₂ M ¹ (BL) M ² (L ² ) ₂ (X) An asymmetric binuclear metal complex represented by _n (provided that M ¹ and M ² are transition metals and are the same But may be different, L ¹ and L ² is a capable of multidentate coordination chelate ligand, L ¹ and L ² are different, the two L ¹ is be different And two L ² may be different, and BL is a bridging ligand having at least two cyclic structures containing a hetero atom, and the coordination atom coordinated to M ¹ and M ² is Which is a heteroatom contained in the cyclic structure, X is a counter ion, n represents the number of counter ions necessary to neutralize the charge of the complex, and
A mononuclear metal complex represented by the formula: (L ¹ ) ₂ M ¹ Cl ₂ in the presence of a base (1) containing lithium (where M ¹ and L ¹ are as defined above) and a formula: (BL ) A production method comprising a step of reacting a mononuclear metal complex represented by M ² (L ² ) ₂ (wherein M ² , L ² and BL are as defined above).   The process according to claim 1, wherein the lithium-containing base (1) is lithium hydroxide and / or an alkoxide of lithium. After reacting a mononuclear metal complex represented by the formula: (L ¹ ) ₂ M ¹ Cl ₂ and a mononuclear metal complex represented by the formula: (BL) M ² (L ² ) ₂ , an acid is added, or 2. A step of adding a salt containing an acid and lithium to isolate a binuclear metal complex represented by the formula: (L ¹ ) ₂ M ¹ (BL) M ² (L ² ) ₂ (X) _n 2. The production method according to 2. A mononuclear metal complex represented by the formula: (L ² ) ₂ M ² Cl ₂ in the presence of a base (2) containing lithium (provided that M ² and L ² are as defined above) and H ₂ (BL ) (Wherein BL is as defined above, and H ₂ (BL) represents a state in which two heteroatoms in BL are protonated), and the formula: (BL) M ² (L ² ) The manufacturing method in any one of Claims 1-3 which further has the process of synthesize | combining the mononuclear metal complex shown by ₂ .   The process according to claim 4, wherein the lithium-containing base (2) is a lithium alkoxide. A mononuclear metal complex represented by the general formula: (BL) M ² (L ² ) ₂ (where M ² is a transition metal, L ² is a chelate-type ligand capable of multidentate coordination, The two L ² may be different, and BL is a bridging ligand having at least two cyclic structures containing a hetero atom, and the coordination atom coordinated to M ² is included in this cyclic structure. Is a heteroatom).
A mononuclear metal complex represented by the formula: (L ² ) ₂ M ² Cl ₂ in the presence of a base (2) containing lithium (provided that M ² and L ² are as defined above) and H ₂ (BL (Wherein BL is as defined above, and H ₂ (BL) represents a state in which two heteroatoms in BL are protonated). An asymmetric binuclear metal complex represented by the general formula: (L ¹ ) ₂ M ¹ (BL) M ² (L ² ) ₂ (X) _n produced by the method according to claim ¹ (6) However, M ¹ and M ² are transition metals and may be the same or different, and L ¹ and L ² are chelate-type ligands capable of multidentate coordination, and L ¹ and L ² Are different, the two L ¹ may be different, the two L ² may be different, and BL is a bridging ligand having at least two cyclic structures containing heteroatoms. Wherein the coordination atoms coordinated to M ¹ and M ² are heteroatoms contained in this cyclic structure, X is a counter ion, and n is a counter ion necessary to neutralize the charge of the complex. Represents a number). An asymmetric binuclear metal complex represented by the general formula: (L ¹ ) ₂ M ¹ (BL) M ² (L ² ) ₂ (X) _n produced by the method according to claim ¹ (6) However, M ¹ and M ² are transition metals and may be the same or different, and L ¹ and L ² are chelate-type ligands capable of multidentate coordination, and L ¹ and L ² Are different, the two L ¹ may be different, the two L ² may be different, X is a counter ion, and n is used to neutralize the charge of the complex. This represents the number of necessary counter ions, and BL is a bridging ligand having at least two cyclic structures containing a hetero atom, and the hetero atoms in which the coordinating atoms coordinated to M ¹ and M ² are contained in this cyclic structure An atom, L ¹ has a substituent capable of being fixed to the semiconductor fine particle, and is mainly (L ¹ ) ₂ M ¹ is a structure in which LUMO is distributed in ¹ ).   A photoelectric conversion element comprising semiconductor fine particles sensitized with the metal complex dye according to claim 8.   The photoelectric conversion element according to claim 9, wherein the semiconductor fine particles are titanium oxide, zinc oxide, or tin oxide.   A photochemical battery using the photoelectric conversion element according to claim 9 or 10.

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