JP2017119805A - Method for producing conjugated polymer having specific thienothiophene-benzodithiophene as unit segment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conjugated polymer that has a high weight average molecular weight and a high maximum absorption wavelength, and obtain high conversion efficiency.SOLUTION: In the production of a conjugated polymer having thienothiophene-benzodithiophene as a unit segment, polyalkylene glycol in a specific molecular weight range is used as a polymerization accelerator to make Suzuki polymerization reaction occur.SELECTED DRAWING: Figure 1

Description

  The present invention can be suitably used as a photoelectric conversion material, and a conjugated polymer having a specific thienothiophene-benzodithiophene as a unit segment using a Suzuki polymerization reaction using polyalkylene glycol or a derivative thereof as a polymerization accelerator. The present invention relates to a method and a photoelectric conversion element using a conjugated polymer obtained from the production method.

  In recent years, organic electronic materials such as conductive oligomers and conductive polymers have been proposed as charge transport materials for organic EL elements, organic thin film transistor materials, and photoelectric conversion materials.

  A photoelectric conversion material is a material that can convert light energy into electrical energy by using a photoelectric effect. When light is irradiated to the photoelectric conversion material, electrons bound to the atoms in the material can move freely by light energy, holes are generated, and these free electrons and holes are efficiently separated. Thus, it is possible to continuously extract energy.

  Photoelectric conversion materials are applied to various uses by utilizing such characteristics, and one of them is a solar cell. Solar cells include types such as dye-sensitized solar cells, solid solar cells, and organic thin film solar cells.

  Polymeric p-type organic semiconductor polymers used for organic thin film solar cells and the like can be synthesized by catalytic polymerization of functionalized monomers. At present, in addition to boron functional group by Suzuki polymerization reaction, tin functional group by Stille coupling, catalytic polymerization by transmetalation including Negishi, Kumada / Tamao, Heck type is applied, and functional group and ligand, In the field of research, efforts have been made to improve the efficiency of reactions by changing external parameters such as reaction media.

  In particular, a thienothiophene-benzodithiophene-based copolymer has been reported to have a high conversion efficiency of 7.4% as a p-type semiconductor of an organic thin film solar cell device (Adv. Mater. 2010, 22, 1-4). : Non-patent document 1). Also, Angew. Chem. Int. Ed. 2011, 50, 9697-9702 (Non-patent Document 2), Japanese Patent No. 5482973 (Patent Document 1) and WO2014 / 0669468A1 (Patent Document 2) report on different thienothiophene-benzodithiophene copolymers. Therefore, the conversion efficiency of organic thin-film solar cells using these has a higher performance exceeding 8%. In such a polymerization reaction of a highly conjugated monomer, increasing the degree of polymerization of the polymer is important for annealing by making a device and improving the sunlight absorption efficiency.

  The present inventors have reported a novel Suzuki polymerization method using a boron functional group having a low environmental toxicity with respect to these conjugated polymers having a thiophene ring (Japanese Patent Laid-Open No. 2014-189647: Patent Document 3). . In this report, by selecting a complex catalyst system using an iodinated derivative as the monomer, a divalent palladium catalyst as the polymerization catalyst, and an organophosphorus ligand having a high electron donating group, it is higher than in the prior art. The production of a conjugated polymer having an average molecular weight and a maximum absorption wavelength shifted by a long wavelength with low environmental impact is enabled. However, since the electron density at the reaction site is low due to halogen substitution, there has been a problem that, when a monomer having low reactivity is used, the desired degree of polymerization cannot be reached.

Japanese Patent No. 5482973 WO2014 / 069468A1 JP 2014-189647 A

Adv. Mater. 2010, 22, 1-4 Angew. Chem. Int. Ed. 2011, 50, 9697-9702

  As described above, a conjugated polymer having a specific thienothiophene-benzodithiophene unit segment does not have a sufficient degree of polymerization or absorption in a long wavelength region as an electron donating material used in an organic thin film solar cell. . The object of the present invention is to provide a conjugated polymer having a larger weight average molecular weight and a higher maximum absorption wavelength than the conjugated polymer obtained by the conventional Suzuki polymerization reaction, and to obtain a higher conversion efficiency.

  As a result of intensive studies to solve the above problems, the present inventors have used a composite catalyst in which palladium and an organic phosphorus ligand having a high electron donating group coexist as a polymerization catalyst, and united thienothiophene-benzodithiophene. In the Suzuki polymerization reaction to obtain a conjugated polymer as a segment, by adding a polyalkylene glycol having a number average molecular weight of less than 600 or a derivative thereof as a polymerization accelerator, the absorption is maximized toward a longer wavelength side with a larger weight average molecular weight. The present inventors have found that a conjugated polymer having a shifted wavelength can be obtained.

That is, the present invention provides the following formula (1):

[In Formula (1),
R ¹ represents a hydrogen atom, a linear or branched alkyl group, an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a group which is partially or completely substituted with fluorine. A chain or branched alkyl group, an aralkyl group partially or fully substituted with fluorine, or an aryl group partially or fully substituted with fluorine,
X is a hydrogen atom, a halogen atom, or a linear or branched alkyl group,
Y is a halogen atom. ]
A thienothiophene derivative represented by:
Following formula (2)

[In Formula (2),
R ² is the same or different and has a hydrogen atom, a linear or branched alkyl group, an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. It may be a heteroaryl group, an alkoxy group, an ester group, an amide group, a linear or branched alkyl group partially or fully substituted with fluorine, an aralkyl group partially or fully substituted with fluorine, or a fluorine. An aryl group partially or fully substituted, or a heteroaryl group partially or fully substituted with fluorine,
R ³ is the same or different and is a boronic acid residue or a boronic acid ester residue obtained by reacting a diol or alcohol with boric acid. ]
A benzodithiophene derivative represented by the following formula: Suzuki polymerization reaction in the presence of a polyalkylene glycol having a number average molecular weight of less than 600 or a derivative thereof:
Following formula (3)


[In Formula (3),
R ¹ represents a hydrogen atom, a linear or branched alkyl group, an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a group which is partially or completely substituted with fluorine. A chain or branched alkyl group, an aralkyl group partially or fully substituted with fluorine, or an aryl group partially or fully substituted with fluorine,
X is a hydrogen atom, a halogen atom, or a linear or branched alkyl group,
R ² is the same or different and has a hydrogen atom, a linear or branched alkyl group, an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. It may be a heteroaryl group, an alkoxy group, an ester group, an amide group, a linear or branched alkyl group partially or fully substituted with fluorine, an aralkyl group partially or fully substituted with fluorine, or a fluorine. A partially or fully substituted aryl group or a heteroaryl group partially or fully substituted with fluorine. ]
The manufacturing method of the conjugated polymer which makes the unit segment the thienothiophene-benzodithiophene represented by these is provided. In this production method, the polyalkylene glycol or its derivative preferably serves as a polymerization accelerator.

  In the method for producing the conjugated polymer, the polyalkylene glycol or the derivative thereof preferably has a number average molecular weight of 100 to 500. The polyalkylene glycol is preferably exemplified by polyethylene glycol.

In the method for producing the conjugated polymer, in the unit segment represented by the formula (3), R ¹ is a linear or branched alkyl group having 1 to 10 carbon atoms, and R ² has 1 to 18 carbon atoms. It is preferably a linear or branched alkyl group or a linear or branched alkyl heteroaryl group having 1 to 10 carbon atoms, and X is preferably a hydrogen atom or a fluorine atom.

  The method for producing the conjugated polymer is preferably Suzuki polymerization performed in a solvent in the presence of a base, a palladium catalyst and an organic phosphorus compound.

In the method for producing the conjugated polymer, the molecular weight of the conjugated polymer is preferably a polystyrene-equivalent weight average molecular weight of 30,000 to 1,000,000.

  And this invention provides the photoelectric conversion element using the conjugated polymer obtained by the manufacturing method of the said conjugated polymer.

  Since the thienothiophene-benzodithiophene conjugated polymer obtained by the production method of the present invention has a high degree of polymerization, the weight average molecular weight increases and the maximum absorption wavelength becomes longer. High conversion efficiency is obtained as the p-type organic semiconductor polymer of the photoelectric conversion element by increasing the maximum absorption wavelength. Therefore, the thienothiophene-benzodithiophene conjugated polymer obtained by the production method of the present invention can be suitably used for a p-type organic semiconductor polymer of a photoelectric conversion element.

FIG. 1 is a diagram showing ultraviolet-visible spectroscopy spectra of the conjugated polymer of Example 1 and the comparative conjugated polymers of Comparative Examples 1 and 3. FIG. 2 is a schematic diagram of a photoelectric conversion element. (A) is a schematic schematic diagram of a forward photoelectric conversion element, (B) is a schematic schematic diagram of a reverse photoelectric conversion element.

  In the method for producing a thienothiophene-benzodithiophene conjugated polymer of the present invention, a polyalkylene glycol, which is a polymerization accelerator, is converted into a halogenated thienothiophene derivative and a boronated benzodithiophene derivative according to the following reaction scheme (4). Alternatively, by performing the Suzuki polymerization reaction in the presence of a derivative thereof, a conjugated polymer having a high degree of polymerization and a maximum absorption wavelength shifted to a longer wavelength side can be obtained. This is shown in Reaction Scheme (4).

[In reaction scheme (4),
R ¹ represents a hydrogen atom, a linear or branched alkyl group, an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a group which is partially or completely substituted with fluorine. A chain or branched alkyl group, an aralkyl group partially or fully substituted with fluorine, or an aryl group partially or fully substituted with fluorine,
R ² is the same or different and has a hydrogen atom, a linear or branched alkyl group, an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. May be a heteroaryl group, an alkoxy group, an ester group, an amide group, a linear or branched alkyl group that is partially or fully substituted with fluorine, or an aralkyl group that is partially or fully substituted with fluorine, or fluorine. An aryl group partially or fully substituted, or a heteroaryl group partially or fully substituted with fluorine,
R ³ is the same or different and is a boronic acid residue obtained by reacting a boronic acid residue or a diol or alcohol with boric acid,
X is a hydrogen atom, a halogen atom, or a linear or branched alkyl group,
Y is a halogen atom. ]

The thienothiophene-benzodithiophene conjugated polymer of the present invention has the formula (3)


[In the formula (3), R ¹ , R ² and X are as defined above. ]
It has a unit segment represented by.

  In the present specification, the “unit segment” represents a basic structural unit of a conjugated polymer obtained by a Suzuki polymerization reaction of a thienothiophene derivative of the formula (1) and a benzodithiophene derivative of the formula (2). However, this chemical formula does not necessarily represent an actual conjugated polymer molecule, and the bonding direction and bonding order of the monomer molecules are actually considered to vary. In addition, other compounds or functional groups may be present at the end or in the middle of the conjugated polymer molecule. In particular, the terminal may have a halogen atom such as bromine or iodine, or a residue of boronic acid or boronic ester. In addition, when capped monomers using an end-capping agent such as an aliphatic compound, aromatic compound or heterocyclic compound having a halogen atom or boronic acid or boronic acid ester residue as a substituent are used. May be at the end.

The thienothiophene-benzodithiophene conjugated polymer of the present invention can be expressed as the following formula (3a), where n is the number of unit segments.


[In the formula (3a),
R ^{1, R 2} and X are ^R 1, ^{R 2} and X as defined above in the formula (3), n represents the degree of polymerization of conjugated polymer, is an integer of 2 to 1,000. ]
N in the formula (3a) represents the polymerization degree of the obtained conjugated polymer, and n is an integer of 2 or more and 1000 or less. Since the conjugated polymer obtained in the present invention has a high weight average molecular weight, n often represents a high number, for example, 50 to 950, preferably 100 to 800.

  The conjugated polymer having a unit segment represented by the above formula (3) (hereinafter, the formula (3) also means the formula (3a)) has a low band gap property, a high carrier mobility, It has characteristics such as a high electron donating property. Therefore, it can be suitably used for a bulk hetero photoelectric conversion element by using it together with an electron accepting material such as a fullerene derivative.

Further, X in the formula (3) is a hydrogen atom, a halogen atom, or a linear or branched alkyl group, and in particular, when it is a halogen atom, particularly a fluorine atom, it deepens the HOMO level of the conjugated polymer. Since it has an effect, it is preferable. R ² in the formula (3) may be the same or different, but is appropriately selected in consideration of solubility in an organic solvent, particularly compatibility with an electron-accepting material such as a fullerene derivative. There is a need. In order to have the above characteristics, the weight average molecular weight of the conjugated polymer and the maximum absorption wavelength are affected, so by increasing the weight average molecular weight, a long wavelength shift of the maximum absorption wavelength occurs, and the weight average molecular weight The increase and control greatly contribute to the improvement of photoelectric conversion efficiency.

  In the present invention, in order to increase the weight average molecular weight and to shift the maximum absorption wavelength accordingly, the polyalkylene glycol having a number average molecular weight of less than 600 or a derivative thereof is added as a polymerization accelerator in the Suzuki polymerization reaction. Achieved. Although not bound by any particular theory, in the Suzuki polymerization reaction, polyalkylene glycol or its derivative acts as a polymerization accelerator in a reaction system comprising a nonpolar solvent and an aqueous solvent containing a base, and an aqueous layer and an organic layer. It is believed that the production of boronate anions at the interface is promoted, the reaction between boronate and halide-palladium complex in the organic layer is accelerated, and the catalytic polymerization reaction proceeds effectively.

  The conjugated polymer (3) having a unit segment of thienothiophene-benzodithiophene according to the present invention is represented by the reaction scheme (4), more specifically, a thienothiophene derivative (1) and a benzodithiophene derivative ( 2) A base, a palladium catalyst, an organophosphorus compound, and a reaction solvent are added to a reaction vessel, and a polyalkylene glycol having a number average molecular weight of less than 600, which is a polymerization accelerator, or a derivative thereof is added to the reaction vessel. A benzodithiophene conjugated polymer is obtained. At this time, it is also possible to add a purification method such as general washing, recrystallization, reprecipitation, extraction, and filtration as a post-treatment.

The method for producing a conjugated polymer having thienothiophene-benzodithiophene as a unit segment of the present invention will be described in more detail sequentially.
Method for producing thienothiophene derivative (1)

[In the formula (1), R ¹ , X and Y are as defined above. ]
Thienothiophene derivatives represented by Org. Chem. 1966, 31, 3363-3365 and J. Org. Am. Chem. Soc. 2009, 131, 7792-7799 and the like.

  A more specific example is described in the reaction scheme as follows:

[In the above scheme, X is as defined above, and Et represents an ethyl group. ]

[In the above scheme, R ¹ , X and Y are as defined above. ]

  First, (6), which is an intermediate of a thienothiophene derivative, is produced using alkyl (ethyl) 2-thiophenecarboxylate (5) as a raw material. Intermediate (7) may have a step of halogenating with a halogenating agent or alkylating with an alkylating agent in order to obtain the desired intermediate (6). The intermediate (8) is subjected to alkyl exchange, and further halogenated using a halogenating agent to obtain (10) which is a raw material of a conjugated polymer having thienothiophene-benzodithiophene as a unit segment.

In the formula (1) or (10), R ¹ may have a hydrogen atom, a linear or branched alkyl group, an aralkyl group which may have a substituent, or a substituent as described above. A good aryl group, a linear or branched alkyl group partially or completely substituted with fluorine, an aralkyl group partially or completely substituted with fluorine, or an aryl group partially or completely substituted with fluorine.

The linear or branched alkyl group in R ¹ is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, and specific examples thereof include, for example, a methyl group, an ethyl group, and an n-propyl group. , Iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, t-butyl group, n-pentyl group, neo-pentyl group, n-hexyl group, n-heptyl group, n-octyl group , 2-methylbutyl group, 2-ethylhexyl group, n-decyl group and the like. Among these, a branched alkyl group is particularly preferable because it contributes to the improvement of the function of the photoelectric conversion element by improving the solubility of the unit segment composed of benzodithiophene and thienothiophene.

Examples of the aralkyl group which may have a substituent in R ¹ include an aralkyl group having 7 to 19 carbon atoms, and specifically include a benzyl group, a phenylethyl group, an α, α′-dimethylbenzyl group, and the like. However, it is not limited to these.

Examples of the aryl group which may have a substituent in R ¹ include an aryl group having 6 to 16 carbon atoms, and specific examples include a phenyl group and a naphthyl group, but are not limited thereto. It is not something.

Specific examples of the linear or branched alkyl group partially or completely substituted with fluorine in R ¹ include a CF ₃ group, a C ₂ F ₅ group, an nC ₃ F ₇ group, and an nC ₄ group. F _9, perfluoroalkyl groups are exemplified by such _{n-C 7 F 15} group _C n _{F 2n + 1} - group (n = 1~18); CHF ₂ group, CH ₂ F group, CH _{(CF 3)} such as ₂ group And the like, but are not limited thereto.

Specific examples of the aralkyl group partially or completely substituted with fluorine in R ¹ include (2-fluorophenyl) methyl group, (3-fluorophenyl) methyl group, (4-fluorophenyl) methyl group, (2,3-difluorophenyl) methyl group, (2,4-difluorophenyl) methyl group, (2,5-difluorophenyl) methyl group, (2,6-difluorophenyl) methyl group, (3,4-difluoro) Phenyl) methyl group, (3,5-difluorophenyl) methyl group, (2,3,4-trifluorophenyl) methyl group, (2,3,5-trifluorophenyl) methyl group, (2,3,6) -Trifluorophenyl) methyl group, (3,4,5-trifluorophenyl) methyl group, (2,4,5-trifluorophenyl) methyl group, (2,4,4) 6-trifluorophenyl) methyl group, (2,3,4,5-tetrafluorophenyl) methyl group, (2,3,4,6-tetrafluorophenyl) methyl group, (2,3,5,6- Examples thereof include, but are not limited to, a tetrafluorophenyl) methyl group and a (pentafluorophenyl) methyl group.

Examples of the aryl group partially or completely substituted with fluorine in R ¹ include a 2-fluorophenyl group, a 3-fluorophenyl group, a 4-fluorophenyl group, a 2,3-difluorophenyl group, and 2,4-difluoro. Phenyl group, 2,5-difluorophenyl group, 2,6-difluorophenyl group, 3,4-difluorophenyl group, 3,5-difluorophenyl group, 2,3,4-trifluorophenyl group, 2,3, 5-trifluorophenyl group, 2,3,6-trifluorophenyl group, 3,4,5-trifluorophenyl group, 2,4,5-trifluorophenyl group, 2,4,6-trifluorophenyl group 2,3,4,5-tetrafluorophenyl group, 2,3,4,6-tetrafluorophenyl group, 2,3,5,6-tetrafluorophenyl group, Examples thereof include, but are not limited to, a pentafluorophenyl group.

Examples of the substituent in the aralkyl group or aryl group in R ^1, is not particularly limited, preferably a linear or branched alkyl group having 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, t-butyl group, n-pentyl group, neo- Examples thereof include, but are not limited to, a pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2-methylbutyl group, a 2-ethylhexyl group, and an n-decyl group.

  The halogenation reaction of the intermediate (6) is halogenated using a general halogenating agent. Examples of halogenating agents include N-fluorobenzenesulfonimide, N-bromosuccinimide, dibromoisocyanuric acid, N-iodosuccinimide, 1,3-diiodo-5,5′-dimethylhydantoin, potassium iodide / periodic acid Although potassium and copper iodide are mentioned, it is not limited to these.

  Examples of the halogenating agent used in the reaction from the intermediate (9) to the raw material of the thienothiophene-benzodithiophene conjugated polymer (10) include N-fluorobenzenesulfonimide, N-bromosuccinimide, dibromoisocyanuric acid, Examples thereof include, but are not limited to, N-iodosuccinimide, 1,3-diiodo-5,5′-dimethylhydantoin, potassium iodide / potassium periodate, and copper iodide.

In the above formula (1) or formula (10), X represents a hydrogen atom, a halogen atom, or a linear or branched alkyl group. Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. As described above, the fluorine atom has an effect of deepening the HOMO level of the conjugated polymer. The linear or branched alkyl is the same as the linear or branched alkyl group in R ¹ , and is preferably a linear or branched alkyl group having 1 to 10 carbon atoms. Specific examples are, for example, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, t-butyl group, n-pentyl group, neo-pentyl. Group, n-hexyl group, n-heptyl group, n-octyl group, 2-methylbutyl group, 2-ethylhexyl group, n-decyl group and the like.

  Similarly, in formula (1) or formula (10), Y is a halogen atom. Examples of the halogen include, but are not limited to, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom as described above for X. Y is preferably an iodine atom.

Production method of benzodithiophene derivative (2)

[In formula (2), R ² and R ³ are as defined above. ]
The benzodithiophene derivative represented by Chem. Ber. 1986, 119, 3198-3203; Am. Chem. Soc. 2009, 131, 7792-7799.

  A more specific example is described in the reaction scheme as follows:

[In the above scheme, Et represents an ethyl group. Me represents a methyl group. ]

[In the above scheme, R ² and R ³ are as defined above. ]

  A benzodithiophene skeleton (13) is synthesized from alkyl thiophene carboxylate (ethyl) (11) as a raw material, and the resulting benzodithiophene skeleton (13) is further reacted to obtain (14). The resulting benzodithiophene derivative (14) can be functionalized with boron to obtain a raw material of thienothiophene-benzodithiophene conjugated polymer (15).

R ² is the same or different and has a hydrogen atom, a linear or branched alkyl group, an aralkyl group which may have a substituent, an aryl group which may have a substituent, and a substituent. Optionally substituted heteroaryl group, alkoxy group, ester group, amide group, linear or branched alkyl group partially or fully substituted with fluorine, aralkyl group partially or fully substituted with fluorine, or fluorine A partially or fully substituted aryl group or a partially or fully substituted heteroaryl group with fluorine. Among them, a heteroaryl group which may have a substituent is particularly preferable because it improves the solubility of a unit segment composed of benzodithiophene and thienothiophene and contributes to the improvement of the function of the photoelectric conversion element.

The linear or branched alkyl group in R ² is preferably a linear or branched alkyl group having 1 to 18 carbon atoms, and specific examples thereof include, for example, a methyl group, an ethyl group, and an n-propyl group. , Iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, t-butyl group, n-pentyl group, neo-pentyl group, n-hexyl group, n-heptyl group, n-octyl group , 2-ethylhexyl group, n-decyl group, octadecyl group and the like, but are not limited thereto.

Examples of the aralkyl group which may have a substituent in R ² include an aralkyl group having 7 to 19 carbon atoms, and specifically include a benzyl group, a phenylethyl group, an α, α′-dimethylbenzyl group, and the like. However, it is not limited to these.

Examples of the aryl group which may have a substituent in R ² include an aryl group having 6 to 16 carbon atoms, and specific examples include a phenyl group and a naphthyl group, but are not limited thereto. It is not something.

Examples of the heteroaryl group which may have a substituent in R ² include a heteroaryl group having 5 to 15 carbon atoms, specifically, a thienyl group, a pyrrolyl group, a furyl group, a pyridyl group, and the like. Can be mentioned. Among these, a 5-membered ring structure such as a thienyl group and a furyl group is particularly preferable from the viewpoint of the flatness of a unit segment composed of thienothiophene and benzodithiophene.

The alkoxy group in R ² represents a linear or branched alkoxy group having 1 to 18 carbon atoms, and more specifically, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, Isobutoxy group, sec-butoxy group, n-pentyloxy group, neopentyloxy group, n-hexyloxy group, 3,3-dimethylbutyloxy group, 2-ethylbutyloxy group, n-heptyloxy group, n-octyl Oxy group, 2-ethylhexyloxy group, n-decyloxy group, n-dodecyloxy group, n-tetradecyloxy group, isotetradecyl group, sec-tetradecyl group, tert-tetradecyl group, n-hexadecyloxy group, n -Octadecyloxy group, etc.

The ester group in R ² represents an ester group substituted with a linear or branched alkyl group having 1 to 10 carbon atoms, and more specifically a methyl ester group, an ethyl ester group, or an n-butyl ester group. , Isobutyl ester group, 2-ethylhexyl ester group, and the like.

The amide group in R ² represents an amide group substituted with a linear or branched alkyl group having 1 to 10 carbon atoms, and includes a methylcarbonylamino group, an ethylcarbonylamino group, a dimethylcarbonylamino group, and a propylcarbonylamino group. And pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, decylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, and the like.

Examples of the linear or branched alkyl group partially or completely substituted with fluorine in R ² include the above-described alkyl groups having 1 to 18 carbon atoms. More specifically, perfluoroalkyl groups C _n F _{2n + 1} exemplified by CF ₃ group, C ₂ F ₅ group, n-C ₃ F ₇ group, n-C ₄ F ₉ , n-C ₇ F ₁₅ group, etc. -Groups (n = 1 to 18); partial fluoroalkyl groups exemplified by CHF ₂ group, CH ₂ F group, CH (CF ₃ ) ₂ group and the like.

Specific examples of the aralkyl group partially or entirely substituted with fluorine in R ² include (2-fluorophenyl) methyl group, (3-fluorophenyl) methyl group, (4-fluorophenyl) methyl group, (2,3-difluorophenyl) methyl group, (2,4-difluorophenyl) methyl group, (2,5-difluorophenyl) methyl group, (2,6-difluorophenyl) methyl group, (3,4-difluoro) Phenyl) methyl group, (3,5-difluorophenyl) methyl group, (2,3,4-trifluorophenyl) methyl group, (2,3,5-trifluorophenyl) methyl group, (2,3,6) -Trifluorophenyl) methyl group, (3,4,5-trifluorophenyl) methyl group, (2,4,5-trifluorophenyl) methyl group, (2,4 , 6-trifluorophenyl) methyl group, (2,3,4,5-tetrafluorophenyl) methyl group, (2,3,4,6-tetrafluorophenyl) methyl group, (2,3,5,6) -A tetrafluorophenyl) methyl group, a (pentafluorophenyl) methyl group, etc. are mentioned, However, It is not limited to these.

Examples of the aryl group partially or completely substituted with fluorine in R ² include 2-fluorophenyl group, 3-fluorophenyl group, 4-fluorophenyl group, 2,3-difluorophenyl group, 2,4-difluoro. Phenyl group, 2,5-difluorophenyl group, 2,6-difluorophenyl group, 3,4-difluorophenyl group, 3,5-difluorophenyl group, 2,3,4-trifluorophenyl group, 2,3, 5-trifluorophenyl group, 2,3,6-trifluorophenyl group, 3,4,5-trifluorophenyl group, 2,4,5-trifluorophenyl group, 2,4,6-trifluorophenyl group 2,3,4,5-tetrafluorophenyl group, 2,3,4,6-tetrafluorophenyl group, 2,3,5,6-tetrafluorophenyl group And pentafluorophenyl group, but are not limited thereto.

Examples of the heteroaryl group partially or completely substituted with fluorine in R ² include heteroaryl groups having 5 to 15 carbon atoms, wherein some or all of the hydrogen atoms are substituted with fluorine. Specifically, a 2-fluorothienyl group, a 3-fluorothienyl group, a 4-fluorothienyl group and the like can be mentioned, but the invention is not limited to these.

The substituent in the aralkyl group, aryl group, and heteroaryl group in R ² is preferably a linear or branched alkyl group having 1 to 10 carbon atoms from the viewpoint of solubility. Specifically, for example, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, t-butyl group, n-pentyl group, neo- Examples thereof include, but are not limited to, a pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2-methylbutyl group, a 2-ethylhexyl group, and an n-decyl group.

R ³ is a boronic acid residue or a boronic acid ester residue. More specifically, a boronic acid residue (—B (OR ^P ) ₂ or —BX X is —O— obtained by reacting a boronic acid residue (—B (OH) ₂ ) or a diol or alcohol with boric acid. -R ^{P -O-;.} R P is a residue obtained by removing OH of diol or alcohol), and preferably boronic acid ester residue obtained by reacting a diol or alcohol and boric acid. More specifically, the boronic acid ester includes boric acid, diols having 1 to 7 carbon atoms such as pinacol, catechol, neopentyl glycol, 1,2-ethanediol, 1,3-propanediol, methanol, ethanol, isopropanol. , A boric acid ester residue obtained by reaction with an alcohol having a linear or branched alkyl group having 1 to 10 carbon atoms such as t-butanol.

  Examples of the boronic acid ester residue include groups represented by the following formulas (a) to (e). The boronic acid ester residue is not limited to these.

[In the above formula, Me represents a methyl group, and Et represents an ethyl group. ]

  When the boron functional group is reacted with the formula (14) to perform boron functionalization, 2-isopropoxy-4,4,5,5-tetramethyl-1,3, manufactured by TCI (Tokyo Chemical Industry Co., Ltd.) Reagents such as 2-dioxaborolane and 2-isopropoxy-4,4,6-trimethyl-1,3,2-dioxaborinane can be used.

Method for Producing Thienothiophene-Benzodithiophene Conjugated Polymer The method for producing thienothiophene-benzodithiophene conjugated polymer is based on the reaction scheme described above. Reaction scheme (4) is listed again.

[In the reaction scheme (4), R ¹ , R ² , R ³ , X and Y are as defined above. ]

  The reaction scheme (4) will be specifically described. A thienothiophene derivative and a benzodithiophene derivative are added to a reaction vessel together with a palladium catalyst, an organic phosphorus compound, a base, and a reaction solvent, and a polyalkylene glycol as a polymerization accelerator or its The Suzuki polymerization reaction proceeds by heating in the presence of the derivative.

Examples of the polymerization accelerator in the present invention include polyalkylene glycol having a number average molecular weight of less than 600 or a derivative thereof. The polyalkylene glycol is a generic name for high molecular compounds having a structure alkylene glycol is polymerized, such as ethylene glycol units polyethylene glycol having a (-CH ₂ CH ₂ O) n in the molecular chain (-CH ₂ CH ₂ O ) n or propylene glycol units _{(polypropylene} glycol having a _{-CH 2 CH 2 CH 2 O)} n in the molecular chain, polybutylene having butylene glycol units _{(-CH 2 CH 2 CH 2 CH} 2 O) n in the molecular chain Glycol etc. The derivatives of polyalkylene glycol include those obtained by etherification, esterification, halogenation, or amination of the terminal hydroxyl group of a polyalkylene glycol unit (— [CH ₂ ] mO) n). Note that n and m in this paragraph are positive integers. In particular, it is preferable to use a polyalkylene glycol having a number average molecular weight of less than 600 because the degree of polymerization is improved and the molecular weight of the resulting thienothiophene-benzodithiophene conjugated polymer is increased. Further, polyethylene glycol having a number average molecular weight of 100 to 500 is particularly preferable, and polyethylene glycol having a number average molecular weight of 200 to 400 is most preferable.

  Suitable polymerization accelerators in the present invention include polyethylene glycol (PEG) and polypropylene glycol (PPG). More specifically, commercially available products such as diethylene glycol, polyethylene glycol-200, polyethylene glycol-300, polyethylene glycol-400, polypropylene glycol-300, and polypropylene glycol-400 (manufactured by Wako Pure Chemical Industries, Ltd.) are inexpensive and available. Easy. The number at the end of glycols manufactured by Wako Pure Chemical Industries, Ltd. represents the number average molecular weight.

  The polymerization accelerator in the present invention is not particularly limited as long as the Suzuki polymerization reaction proceeds, but it is preferably 10 equivalents or more with respect to the thienothiophene derivative. Furthermore, it is more preferable if it is 25 equivalents or more.

  Examples of the palladium catalyst used in the reaction scheme (4) include known zero-valent or divalent palladium catalysts.

Examples of zero-valent palladium catalysts include tetrakis (triphenylphosphine) palladium represented by Pd (PPh ₃ ) ₄ , tris (dibenzylideneacetone) dipalladium represented by Pd ₂ (dba) ₃ , and Pd (dba) ₂ And bis (dibenzylideneacetone) palladium represented by Especially, it is preferable to use tris (dibenzylidene acetone) dipalladium, tetrakis (triphenylphosphine) palladium, etc. from a polymeric viewpoint.

Examples of the divalent palladium catalyst include palladium chloride represented by Pd (II) Cl ₂ , palladium acetate represented by Pd (II) (OAc) ₂ , and bis (Pd (II) (acac) ₂ represented by Acetylacetone) palladium, bis (diphenylphosphino) ferrocenedichloropalladium represented by Pd (II) (dppf) Cl ₂ , bis (triphenylphosphine) dichloropalladium represented by Pd (II) (PPh ₃ ) ₂ Cl ₂ Etc. Of these, palladium chloride, palladium acetate and the like are preferably used from the viewpoint of polymerizability.

  The amount of the palladium catalyst in the present invention is not particularly limited as long as the amount of the Suzuki polymerization reaction proceeds. For example, the amount is 0.001 mol% to 10.0 mol%, preferably 0, with respect to 1 mol of the benzodithiophene derivative. It is 0.01 mol%-5.0 mol%, More preferably, it is 0.1 mol%-2.0 mol%. If it is less than 0.001 mol%, there is a problem that the reaction is not completed, and if it is added more than 10.0 mol%, there is a problem that the production cost increases.

Examples of the organic phosphorus compound in the present invention include 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl represented by SPhos, tri (o-tolyl) phosphine represented by (o-tolyl) ₃ P, (t _{-bu) 3} tri (t-butyl) phosphine represented by P, such as tricyclohexylphosphine represented by Cy ₃ P and the like. Of these, 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl (SPhos) is preferably used from the viewpoint of polymerizability.

  The organophosphorus compound in the present invention is presumed to coordinate with the palladium catalyst and become a ligand of the palladium catalyst. By using a catalyst comprising this palladium and an organophosphorus compound, the reactivity is increased and the reaction proceeds easily.

  Although the amount of the organic phosphorus compound in the present invention is not particularly limited as long as the Suzuki polymerization reaction proceeds, for example, 0.5 mol% to 10.0 mol% is preferable with respect to the thienothiophene derivative.

  As for the palladium catalyst in the present invention, it is desirable that the palladium catalyst and the organic phosphorus compound are mixed in advance with a reaction solvent to be used and then introduced into the system.

  The base in the present invention is not particularly specified as long as it is a general base, and any base can be used, but bases such as sodium hydroxide, sodium carbonate, tripotassium phosphate are produced. It is preferable in terms of In particular, tripotassium phosphate is preferable.

  The base in the present invention is not particularly limited as long as the Suzuki polymerization reaction proceeds, but it is preferably 2 equivalents or more with respect to the thienothiophene derivative.

  Examples of the reaction solvent in the present invention include aromatic solvents such as toluene and xylene, halogen-containing solvents such as orthodichlorobenzene and chloroform, and two-phase mixed solvents of water and thienothiophene derivatives and benzodithiophenes. This is preferable because it dissolves both an organic compound such as a derivative and an inorganic compound such as a base. One example is a mixed solvent of toluene and water.

  The reaction temperature in this invention is 0 degreeC-150 degreeC, Preferably it is 30 degreeC-130 degreeC. When the reaction temperature is 0 ° C. or lower, the progress of the reaction is slow, and when the reaction temperature is 150 ° C. or higher, it decomposes and a low molecular weight copolymer may be produced.

  The method for taking out the conjugated polymer of the present invention is not particularly limited. For example, it is allowed to cool to room temperature, and then poured into a mixed solution of water and methanol. Is preferable.

  The solid substance of the conjugated polymer subjected to the above polymerization reaction can be obtained by filtration. The filtration method is not particularly limited, and specifically, for example, Nutsche, a pressure filter, centrifugal separation, a filter press, or the like can be used. The obtained conjugated polymer having thienothiophene-benzodithiophene as a unit segment may be washed with methanol and / or water.

  The method for removing the palladium catalyst in the present invention is not particularly limited, and for example, it can be removed by filtration after dissolving a conjugated polymer having thienothiophene-benzodithiophene as a unit segment in an organic solvent such as chloroform.

  The production method of the present invention can also include a drying step. As a drying method, a known method can be used. More specifically, there are a method of drying by heat and a method of drying by vacuum, and a combination thereof can also be used.

  The production method of the present invention can also include a step of end-capping the terminal of a conjugated polymer having thienothiophene-benzodithiophene as a unit segment. Examples of the end capping agent include aliphatic compounds, aromatic compounds, and heterocyclic compounds having a halogen atom, a boronic acid, or a boronic acid ester residue, and examples thereof include benzene and thiophene.

  The end capping agent can be added, for example, at the final stage of the polymerization reaction, and a plurality of end capping agents can be used in combination. In the case of the Suzuki polymerization reaction, the end group can be selected by sequentially adding an end capping agent having a halogen atom and an end capping agent having a boronic acid or boronic acid ester residue. The end group can be selected by adjusting the amount of the end capping agent added.

  The polystyrene-converted weight average molecular weight of the conjugated polymer having thienothiophene-benzodithiophene as a unit segment is 30,000 to 1,000,000, more preferably 50,000 to 600,000.

  A particularly preferred embodiment 1 of the thienothiophene-benzodithiophene unit segment can be represented by the following formula (16).

[In the above formula (16), R ^a is a linear or branched alkyl group having 1 to 10 carbon atoms, and R ^b is a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. ]

  Particularly preferred embodiment 2 of the thienothiophene-benzodithiophene unit segment can be represented by the following formula (17).

[In the above formula (17), R ^a is a linear or branched alkyl group having 1 to 10 carbon atoms, and R ^b is a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. ]

  A particularly preferred embodiment 3 of the thienothiophene-benzodithiophene unit segment can be represented by the following formula (18).

[In the above formula (18), R ^a is a linear or branched alkyl group having 1 to 10 carbon atoms, and R ^c is a linear or branched alkyl group having 1 to 18 carbon atoms. ]

(Photoelectric conversion element)
A photoelectric conversion element using a conjugated polymer having thienothiophene-benzodithiophene as a unit segment according to the present invention is, for example, as shown in the schematic diagram of FIG. The photoelectric conversion element comprises a support, a pair of electrodes, a buffer layer such as a hole transport layer and an electron transport layer, a p-type organic semiconductor material (electron-donating material) and an n-type organic semiconductor material (electron-accepting material). At least a structure in which photoelectric conversion layers mixed and formed is laminated is formed. Although classified into the forward photoelectric conversion element (A) and the reverse photoelectric conversion element (B) according to the stacking order, description of Synthetic Metals 177, 48-51 (2013) and Japan J Applied Physics 53, 05FJ08 (2014) As described above, in recent years, an inverted photoelectric conversion element in which a non-corrosive metal such as gold or silver is laminated on the top has attracted attention in terms of durability of the organic thin film solar cell device.

  The method for producing a photoelectric conversion element of the present invention has a number average molecular weight of less than 600 using a thienothiophene derivative represented by the formula (1) and a benzodithiophene derivative represented by the formula (2) as a polymerization accelerator. In the presence of the polyalkylene glycol or its derivative, a Suzuki polymerization reaction is performed to obtain a conjugated polymer having thienothiophene-benzodithiophene represented by the formula (3) as a unit segment, and the conjugated polymer is converted to p. At least a step of laminating a photoelectric conversion layer used as a type organic semiconductor material.

  The support in the photoelectric conversion element of the present invention is not particularly limited as long as the electrode can be stably held, but it is necessary to transmit light in a predetermined wavelength region used in the photoelectric conversion element. Therefore, glass, transparent polymer films (polyethylene terephthalate, polycarbonate, etc.) can be used.

  The electrode material of the organic photoelectric conversion element of the present invention is not particularly limited, but in the case of a cathode in a forward photoelectric conversion element, the energy barrier is small with respect to the LUMO level of the electron-accepting material, and the finishing function is relatively For example, Al, Pt, Ir, Cr, ZnO, carbon nanotube (CNT), and alloys and composites thereof are selected. On the other hand, in the case of an anode in an inverted photoelectric conversion element, a high-function metal such as gold can be used.

  Since the electrode paired with the cathode of the forward photoelectric conversion element or the anode of the reverse photoelectric conversion element needs to have transparency, titanium oxide, zinc oxide, ITO (tin-doped indium oxide), FTO (fluorine-doped) A transparent material such as tin oxide) can be used.

  The method for forming the electrode is not particularly limited, and examples thereof include vacuum deposition and various sputtering methods.

  For the hole transport layer in the buffer layer, a material having a rectifying effect that prevents electrons generated in the photoelectric conversion layer from flowing to the cathode electrode is preferably used. More specifically, metal oxides such as PEDOT: PSS (poly (3,4-ethylenedioxythiophene) polystyrene sulfate), triarylamine compounds, molybdenum oxide, nickel oxide, and tungsten oxide can also be used.

  For the electron transport layer in the buffer layer, a material having a rectifying effect that does not flow holes generated in the photoelectric conversion layer to the anode electrode is preferably used. More specifically, inorganic oxides such as titanium oxide, zinc oxide, and gallium oxide, and alkali metal compounds such as lithium fluoride, sodium fluoride, and cesium fluoride can also be used.

  In addition, a method for forming a photoelectric conversion layer including a p-type semiconductor material and an n-type semiconductor material is not particularly limited, and examples thereof include a coating method such as spin coating and bar coating, and a vacuum deposition method. Among these, a method of applying a solution containing a p-type semiconductor material and an n-type semiconductor material is preferable. The solvent contained in this solution is not particularly limited, and for example, chlorobenzene, orthodichlorobenzene, chloroform, dichloromethane, toluene, tetrahydrofuran and the like can be used.

  The conjugated polymer of the present invention is suitably used as a p-type organic semiconductor material because it undergoes a Suzuki polymerization reaction using polyalkylene glycol as a polymerization accelerator, so that it is polymerized and has excellent electron donating properties. be able to.

  On the other hand, the n-type organic semiconductor material is not particularly limited. For example, an oxazole derivative, a triazole derivative, a phenanthroline derivative, a phosphine oxide derivative, a fullerene compound, a carbon nanotube (CNT), a poly-p-phenylene vinylene-based polymer, and a cyano group. And a derivative (CN-PPV) into which is introduced. Among these, a fullerene compound is preferable because it is an n-type semiconductor material that is stable and has high carrier mobility.

Specific examples of the fullerene compound include [6,6] -phenyl C ₆₁ butyric acid methyl ester (PC ₆₀ BM) and [6,6] -phenyl C ₇₁ -butyric acid methyl ester (PC ₇₀ BM). ) And the like. Among these, PC ₆₀ BM and PC ₇₀ BM are preferable from the viewpoint of having excellent electron acceptability. These n-type semiconductor materials can be used alone or in combination of two or more.

  When the photoelectric conversion layer is an active layer of a bulk heterojunction type and is formed by a coating method, 0.1 wt% to 10 wt% of a low molecular weight compound is added to the solvent from the viewpoint of improving the photoelectric conversion rate. Also good. Examples of the low molecular weight compound include alkane having a substituent, alkanethiol having a substituent, and an aromatic compound.

  Examples of the alkane having a substituent include 1,4-diiodobutane, 1,5-diiodopentane, 1,6-diiodohexane, 1,7-diiodopentane, 1,8-diiodooctane, and 1,9-diiodononane. Suitable examples include halogenated alkanes such as 1,10-diiododecane.

  As the alkanethiol having a substituent, 1,4-butanedithiol, 1,5-hexanedithiol, 1,6-hexanedithiol, 1,7-heptanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, Preferred examples include alkanethiols such as 1,10-decanedithiol.

  Suitable examples of aromatic compounds include 1-chloronaphthalene and 1-bromonaphthalene.

  Hereinafter, the present invention will be described more specifically with reference to examples of the present invention. These should not be construed as limiting the invention.

Production Example 1 Synthesis of Halogenated Thienothiophene Derivative [Compound Example 1-a]
Thienothiophene derivatives represented by the following formula (19) Am. Chem. Soc. 2009, 131, 7792-7799, and the yield was 1.3 g (43.3% yield).

In this embodiment, CH ₃ is abbreviated as Me, C ₂ H ₅ is abbreviated as Et, and n-C ₄ H ₉ is abbreviated as Bu.

[Compound Example 1-b]
1.3 g of [Compound Example 1-a] represented by the formula (19) was added to 14 g of dimethylformamide, and the atmosphere was replaced with nitrogen, the reaction vessel was shielded from light, and cooled to 5 ° C. or lower with an ice bath. 2.4 g of N-iodosuccinimide was added and stirred at 5 ° C. or lower for 1 hour and at room temperature for 24 hours. The reaction product was put into 100 g of a saturated aqueous ammonium chloride solution and extracted with 260 g of toluene. Toluene was distilled off under reduced pressure, and purification was performed by column chromatography using toluene. Furthermore, by performing reprecipitation operation with 13 g of hexane, [Compound Example 1-b] represented by the following chemical formula (20) having a yield of 1.6 g (yield 68.5% from [Compound 1-a]) was obtained. Obtained.

About obtained compound example 1-b, elemental analyzer (EA: Perkin-Elmer Japan 2400II fully automatic elemental analyzer) and ¹ H-nuclear magnetic resonance apparatus, ¹³ C-nuclear magnetic resonance apparatus (NMR: JEOL Ltd.) JNM-AL300), Fourier transform infrared spectrophotometer (FT-IR: JIR-SPX60S manufactured by JEOL Ltd.), gas chromatography mass spectrometer (GC / MS: GC / MS Spectrometer 6890N / 5973N manufactured by Agilent Technologies) Then, differential heat / thermogravimetry (TG / DTA: TG / DTA6200 manufactured by SII Nano Technologies) was measured. The results are shown below. From these results, it was confirmed that Compound Example 1-b had the structure of the chemical formula (20).

¹ H NMR (CDCl ₃ , 300 MHz) δ (ppm):
4.26-4.23 (2H, m), 1.72-1.66 (1H, m), 1.49-1.32 (8H, m), 0.97-0.89 (6H, m )
¹³ C NMR (CDCl ₃ , 75.45 MHz) δ (ppm):
161.2, 161.1, 151.1, 147.3, 142.4, 142.3, 139.6, 139.3, 119.3, 119.2, 68.2, 65.3, 65. 2, 64.4, 64.3, 38.8, 30.4, 28.9, 23.8, 22.9, 14.111.1
IR (KBr) (cm ⁻¹ ):
2958 (s), 2929 (s), 2859 (s), 1710 (s), 1573 (s), 1535 (m), 1461 (m), 1427 (s), 1398 (s), 1369 (s), 1280 (s), 1267 (s), 1251 (s), 1201 (vs), 1060 (s), 1037 (m), 977 (w), 952 (w), 923 (w), 759 (s), 669,516
GC-MS m / z Calcd. for [M] ⁺ : 566.23. Found: 566.00 (49.4%)

[Compound Example 1-c]
1.3 g of [Compound Example 1-a] represented by the chemical formula (19) was added to 14 g of dimethylformamide, and the atmosphere was replaced with nitrogen. The reaction vessel was shielded from light and cooled to 5 ° C. or lower with an ice bath. 2.4 g of N-bromosuccinimide was added and stirred at 5 ° C. or lower for 1 hour and at room temperature for 24 hours. The reaction product was put into 100 g of a saturated aqueous ammonium chloride solution and extracted with 260 g of toluene. Toluene was distilled off under reduced pressure, and purification was performed by column chromatography using toluene. Furthermore, by performing reprecipitation operation with 13 g of hexane, [Compound Example 1-c] represented by the following chemical formula (21) with a yield of 1.9 g (yield 69.0% from [Compound 1-a]) was obtained. Obtained.

[Compound Example 2-a]
Thienothiophene derivatives represented by the following chemical formula (22) Am. Chem. Soc. 2009, 131, 7792-7799, and the yield was 2.5 g (yield 89.9%).

[Compound Example 2-b]

  The thienothiophene derivative represented by the following chemical formula (23) is the same as [Compound Example 1-b] except that [Compound Example 2-a] 1.5 g was used instead of [Compound Example 1-a]. Synthesis by the method yielded 1.3 g (yield 57.8%).

  The chemical structure of Compound 2-b was confirmed in the same manner as Compound 1-b. The results are shown below.

¹ H NMR (CDCl ₃ , 300 MHz) δ (ppm):
0.96 (3H, t, _JH-H = 7.5 Hz), 1.02 (3H, t, _JH-H = 6.3 Hz), 1.30 (1H, m), 1.52 (1H M), 1.83 (1H, m), 4.22 (2H, m)
¹³ C NMR (CDCl ₃ , 75.45 MHz) δ (ppm):
11.3, 16.4, 26.0, 34.2, 64.3, 64.4, 65.2, 65.3, 70.4, 119.1, 119.3, 139.3, 139. 6,142.3,142.4,147.3,151.1,161.1,161.2
IR (NaCl) (cm ⁻¹ ):
458 (w), 760 (m), 1060 (m), 1203 (vs), 1251 (m), 1279 (m), 1367 (m), 1378 (m), 1400 (m), 1427 (m), 1464 (w), 1535 (w), 1574 (s), 1687 (m), 1711 (s), 2877 (w), 2933 (w), 2962 (m)
GC-MS m / z Calcd. for [M] ⁺ : 524.15. Found: 523.90 (60.5%)
[Compound Example 2-c]

  The thienothiophene derivative represented by the following chemical formula (24) is the same as [Compound Example 1-c] except that 1.3 g of [Compound Example 2-a] is used instead of [Compound Example 1-a]. Thus, a yield of 1.7 g (yield 61.2%) was obtained.

Production Example 3 Synthesis of benzodithiophene derivative [Compound Example 3-a]
The benzodithiophene derivative represented by the following chemical formula (25) Am. Chem. Soc. 2009, 131, 7792-7799, and the yield was 9.2 g (yield 64.8%).

[Compound Example 3-b]
Into a 1 L flask, 430 ml of tetrahydrofuran and 17.8 g (90.8 mmol) of 2-ethylhexylthiophene were added, and the atmosphere was replaced with nitrogen and cooled to 0 ° C. or lower with an ice / acetone bath. 430 ml (99.9 mmol) of a 1.6 M butyllithium / hexane solution was added dropwise over 15 minutes, and the mixture was heated to 50 ° C. for 0.5 hour at 0 ° C. or lower and then stirred for 1 hour. Compound Example 3-a represented by formula (25) 4,8-dihydrobenzo [1,2-b: 4,5-b ′] dithiophene-4,8-dione 5.0 g (22.7 mmol) The mixture was further heated and stirred at 50 ° C. for 1 hour. After cooling to room temperature, an aqueous solution of tin chloride (II) dihydrate 40.5 g (179 mmol) / 10% hydrochloric acid 86 ml was added, and the mixture was further stirred at room temperature for 1.5 hours. The reaction product was added to 1.0 kg of ice water, the organic layer was separated, and the aqueous layer was extracted twice with 0.3 L of ethyl acetate. The organic layers were combined and washed sequentially with 0.5 L of saturated aqueous ammonium chloride solution and 0.5 L of brine. Using magnesium sulfate, dehydration, filtration, and concentration by an evaporator were carried out to obtain 22.8 g of a brown liquid. Further, a yellow fraction with Rf = 0.4 was separated by silica gel chromatography (150 g of Merck silica gel 60, chloroform: hexane = 1: 20). Concentration in an evaporator and drying under reduced pressure at 50 ° C. for 16 hours, 4,8-bis (5- (2-ethylhexyl) thiophen-2-yl) benzo [1, represented by the following chemical formula (26) as a yellow liquid 2-b: 4,5-b ′] dithiophene (Compound Example 3-b) was obtained in an amount of 11.3 g (yield: 85.9%).

  The chemical structure of compound 3-b was confirmed in the same manner as compound 1-b. The results are shown below.

¹ H NMR (CDCl ₃ , 300 MHz) δ (ppm):
0.94 (12H, t, _JH-H = 7.5 Hz), 1.34 (8H, m), 1.41 (8H, m), 1.68 (2H, m), 2.85 (4H , D, _JH-H = 6.6 Hz), 6.88 (2H, d, _JH-H = 3.6 Hz), 7.28 (2H, d, _JH-H = 3.6 Hz), 7 .44 (2H, d, _JH-H = 5.7 Hz), 7.64 (2H, d, _JH-H = 5.7 Hz)
¹³ C NMR (CDCl ₃ , 75.45 MHz) δ (ppm):
10.9, 14.2, 23.0, 25.7, 28.9, 32.5, 34.3, 41.5, 123.4, 124.1, 125.4, 127.4, 127. 7, 136.5, 137.2, 139.0, 145.7
IR (KBr) (cm ⁻¹ ):
3068, 2958 (vs), 2925 (vs), 2858 (s), 1483 (w), 1457 (m), 1376 (w), 1232, 1214, 1099 (w), 1056, 811 (m), 800 ( m), 759 (s), 742 (s), 665 (w), 644, 528, 507
GC-MS m / z Calcd. for [M] ⁺ : 578.96. Found: 578.00 (100.0%)

[Compound Example 3-c]
A 500 ml flask was charged with 200 ml of tetrahydrofuran and 10.0 g (17.3 mmol) of [Compound Example 3-b] represented by the formula (26), and cooled to −78 ° C. or lower in a nitrogen atmosphere and a dry ice / ethanol bath. 27 ml (43 mmol) of 1.6M butyllithium / hexane solution was added dropwise over 15 minutes, and the mixture was stirred at the same temperature for 1 hour. 8.8 ml (43 mmol) of 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane was added, stirred at the same temperature for 1 hour, warmed to room temperature, and heated at room temperature for 17 hours. Stirring was performed. 200 ml of saturated aqueous ammonium chloride solution and 200 ml of ethyl acetate were added to the reaction product, the organic layer was separated, and the aqueous layer was extracted twice with 100 ml of ethyl acetate. The organic layers were combined and washed sequentially with 200 ml of saturated aqueous ammonium chloride solution and 200 ml of brine. Dehydration using magnesium sulfate, filtration, and concentration by an evaporator were performed. Drying under reduced pressure at 40 ° C. for 2 hours gave 14.2 g of a brown solid. The obtained solid was completely dissolved by heating with 0.8 L of acetone, reprecipitated at room temperature, filtered, and washed with 100 ml of acetone. The filtrate was concentrated and the same reprecipitation operation was performed using 200 ml of acetone. The obtained solids were combined, dried under reduced pressure at 40 ° C. for 16 hours, and 2,6-bis (4 ′, 4 ′, 5 ′, 5′-tetramethyl) represented by the following chemical formula (27) as an orange solid. -1 ′, 3 ′, 2′-dioxaborolan-2′-yl) -4,8-bis (5- (2-ethylhexyl) thiophen-2-yl) benzo [1,2-b: 4,5-b '] Dithiophene (Compound Example 3-c) (9.7 g, yield 67.7%) was obtained.

  The chemical structure of compound 3-c was confirmed in the same manner as compound 1-b. The results are shown below.

¹ H NMR (CDCl ₃ , 300 MHz) δ (ppm):
0.95 (12H, t, _JH-H = 7.2 Hz), 1.35 (40H, m), 1.68 (2H, m), 2.84 (4H, d, _JH-H = 6) .6 Hz), 6.86 (2H, d, _JH-H = 3.6 Hz), 7.28 (2H, d, _JH-H = 3.6 Hz), 8.14 (2H, s)
¹³ C NMR (CDCl ₃ , 75.45 MHz) δ (ppm):
10.9, 14.2, 23.0, 24.7, 25.7, 28.9, 32.5, 34.3, 41.4, 84.5, 124.8, 125.4, 128. 1,133.7, 136.9, 138.3, 142.6, 145.8
IR (KBr) (cm ⁻¹ ):
2958 (m), 2927 (m), 2858 (w), 1537 (s), 1463, 1427 (w), 1371 (s), 1342 (vs), 1305 (s), 1270 (m), 1251 (w ), 1139 (vs), 1018 (w), 993 (w), 954, 850 (m), 804, 667 (m)
m. p. : 186.3
MALDI-TOF MS m / z Calcd. for [M-2 (BPin) + H] ⁺ : 576.94. Found: 576.23

Production Example 4 Synthesis of benzodithiophene derivative [Compound Example 4-a]
The benzodithiophene derivative represented by the following chemical formula (28) Am. Chem. Soc. 2009, 131, 7792-7799, and the yield was 11.3 g (yield 69.6%).

[Compound Example 4-b]
8.0 g of [Compound Example 4-a] represented by the above chemical formula (28) was added to 140 g of tetrahydrofuran, followed by nitrogen substitution and cooling to −70 ° C. 30 g of 1.6M butyllithium / hexane solution was added dropwise and stirred for 30 minutes. 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (13.3 g) was added thereto, stirred for 30 minutes, and further stirred at room temperature for 18 hours. 30 g of methanol and 200 g of water were added to the reaction product, and extracted with 540 g of ethyl acetate. Ethyl acetate and tetrahydrofuran were distilled off under reduced pressure, and reprecipitation was further performed with hexane, and the yield was 7.1 g (yield 56.4% from [Compound Example 4-a]) represented by the following formula (29). [Compound Example 4-b] was obtained.

About the obtained [compound 4-b], the elemental analysis and the measurement result of ¹ HNMR, ¹³ CNMR, and IR are shown below. These results confirmed that [Compound 4-b] had the structure of the chemical formula (29).

_{^{1 H NMR (300.4 MHz, CDCl}} 3 /ppm):δ0.94(t, J H-H = 7.3 6H), 0.99 (t, J H-H = 7.8 6H), 1 .39 (s, 24H), 1.57 (m, 16H), 1.83 (m, 2H), 4.22 (d, _JH-H = 5.4 4H), 8.00 (s, 2H) )
¹³ C NMR (75.45 MHz, CDCl ₃ / ppm): δ 11.3, 14.1, 23.2, 23.8, 24.8, 29.2, 30.4, 40.7, 76.2 84.5, 131.0, 132.7, 133.6, 145.1
IR (KBr / cm ⁻¹ ): ν 667 (m), 850 (m), 1039 (w), 1137 (vs), 1168, 1270 (w), 1315 (vs), 1355 (s), 1450 (w ), 1540 (s), 2871 (w), 2927 (m), 2975 (m), 3430
MALDI-TOF MS m / z Calcd. for [M + H] ⁺ : 699.64. Found: 699.47

Synthesis of conjugated polymers with thienothiophene-benzodithiophene as unit segments
Example 1 [Conjugated Polymer 1]
2. Toluene 1.2 ml, Compound Example 1-b 130 mg (0.22 mmol), Compound Example 3-c 200 mg (0.24 mmol), Palladium acetate 1.0 mg (2.0 mol%), SPhos in a pressure test tube reactor. 6 mg (4.0 mol%) was added and stirred for 30 minutes. Furthermore, 145 mg (0.68 mmol) of tripotassium phosphate and 0.6 ml of polyethylene glycol-200 / 1.2 ml of distilled water were added, and the mixture was heated and stirred at 90 ° C. for 15 hours. 3 drops of iodobenzene were added, and 3 drops of (4 ′, 4 ′, 5 ′, 5 ′,-tetramethyl-1 ′, 3 ′, 2′-dioxaborolan-2′-yl) benzene were added for 6 hours. The mixture was heated and stirred at 90 ° C for an hour. The reaction product was added to 100 ml of 90% aqueous methanol solution, and the slurry was collected by filtration and washed with 50 ml of 90% aqueous methanol solution and 50 ml of methanol. It dried under reduced pressure at 50 degreeC for 15 hours, and black solid was obtained.

  The obtained solid was refluxed and stirred in each solvent for 1 hour using 70 ml of methanol, 70 ml of acetone, and 70 ml of hexane, and filtered while heating to remove the dissolved matter of each solvent. Further, 70 ml of toluene was stirred under reflux for 1 hour and filtered while hot, and the filtrate was concentrated to 10 ml with an evaporator. The concentrated solution was put into 50 ml of methanol to make a slurry, filtered, and washed with 20 ml of methanol. It dried under reduced pressure at 50 degreeC for 16 hours, and 81.7 mg (yield 40.4%) of conjugated polymer 1 shown to following formula (30) as black solid was obtained.

  About the obtained conjugated polymer 1, an elemental analysis and IR measurement result are shown below. These results confirmed that [conjugated polymer 1] has the structure of the formula (30).

Measurement results of elemental analysis

IR (KBr) (cm ⁻¹ ): ν 661 (w), 759 (w), 798 (m), 1014 (w), 1058 (m), 1152 (m), 1182 (w), 1247 (m) , 1292 (w), 1375 (m), 1396 (w), 1457 (m), 1565 (m), 1700 (s), 2856 (s), 2923 (vs), 2954 (s)

  The molecular weight distribution of the obtained conjugated polymer 1 was measured with a Waters 515 HPLC system (manufactured by Waters, Japan) under the following measurement conditions, and the molecular weight distribution and the weight average molecular weight were confirmed.

As GPC measurement conditions, 2 mg of a sample to be measured was dissolved in 10 ml of tetrahydrofuran, filtered through a solvent-resistant membrane filter having a pore diameter of 0.5 μm to obtain a sample solution, and measurement was performed under the following conditions.
Column: Downsize column for rapid analysis KF-604 (manufactured by Shodex) × 2
Mobile phase: Tetrahydrofuran Column oven temperature: 40 ° C
Detection wavelength: 254 nm

  Moreover, in calculating the molecular weight of the sample, a molecular weight calibration curve prepared with standard polystyrene (Shodex STANDARD SM-105 manufactured by Showa Denko KK) was used.

  It was confirmed that the weight average molecular weight (Mw) of the conjugated polymer 1 in Example 1 measured under the above conditions was 297,899.

The absorbance of the obtained conjugated polymer 1 was measured with an ultraviolet-visible spectrophotometer UV-1800 (Shimadzu Corporation) under the following measurement conditions, and the maximum absorption wavelength λ _max was measured.

  As the measurement conditions of absorbance, 2 mg of a sample to be measured was dissolved in 100 ml of chloroform, filtered through a solvent-resistant membrane filter having a pore diameter of 0.5 μm to obtain a sample solution, and measured under the following conditions.

FIG. 1 shows an ultraviolet-visible spectrum of the conjugated polymer 1 in Example 1 measured under the above measurement conditions. As a result of measuring the absorbance, the maximum absorption wavelength λ _max was 694.0 nm.

Table A shows the results of the weight average molecular weight and the maximum absorption wavelength measured under the above measurement conditions.

Example 2 [Conjugated polymer 2]
2. Toluene 1.2 ml, Compound Example 2-b 116 mg (0.22 mmol), Compound Example 3-c 200 mg (0.24 mmol), Palladium acetate 1.0 mg (2.0 mol%), SPhos in a pressure test tube reactor. 6 mg (4.0 mol%) was added and stirred for 30 minutes. Furthermore, 145 mg (0.68 mmol) of tripotassium phosphate and 0.6 ml of polyethylene glycol-200 / 1.2 ml of distilled water were added, and the mixture was heated and stirred at 90 ° C. for 15 hours. 3 drops of iodobenzene were added, and 3 drops of (4 ′, 4 ′, 5 ′, 5 ′,-tetramethyl-1 ′, 3 ′, 2′-dioxaborolan-2′-yl) benzene were added for 6 hours. The mixture was heated and stirred at 90 ° C. for an hour. The reaction product was added to 100 ml of 90% aqueous methanol solution, and the slurry was collected by filtration and washed with 50 ml of 90% aqueous methanol solution and 50 ml of methanol. It dried under reduced pressure at 50 degreeC for 15 hours, and black solid was obtained.

  The obtained solid was refluxed and stirred in each solvent for 1 hour using 70 ml of methanol, 70 ml of acetone, and 70 ml of hexane, and filtered while heating to remove the dissolved matter of each solvent. Further, 70 ml of toluene was stirred under reflux for 1 hour and filtered while hot, and the filtrate was concentrated to 10 ml with an evaporator. The concentrated solution was put into 50 ml of methanol to make a slurry, filtered, and washed with 20 ml of methanol. It dried under reduced pressure at 50 degreeC for 16 hours, and obtained 186 mg (yield 98.7%) of conjugated polymer 2 shown to following formula (31) as black solid.

  About the obtained conjugated polymer 2, an elemental analysis and the measurement result of IR are shown below. These results confirmed that the conjugated polymer 2 has the structure of the formula (31).

Measurement results of elemental analysis

IR (KBr) (cm ⁻¹ ): ν 661 (w), 684, 746 (w), 798 (m), 1047 (w), 1062 (m), 1178 (m), 1240 (m), 1274 ( m), 1376 (m), 1457 (m), 1533 (w), 1710 (s), 2854 (s), 2869 (s), 2921 (vs), 2954 (vs)

  As a result of measuring the molecular weight distribution of the obtained conjugated polymer 2 by the same method as in Example 1, it was confirmed that the weight average molecular weight of the conjugated polymer 2 was (Mw) of 117,479.

The absorbance of the obtained conjugated polymer 2 was measured by the same method as in Example 1. As a result, the maximum absorption wavelength λ _max was 690.5 nm.

  Table 1 shows the results of the weight average molecular weight and the maximum absorption wavelength measured under the above measurement conditions.

Example 3 [Conjugated Polymer 3]
2. Toluene 1.2 ml, compound example 1-b 130 mg (0.22 mmol), compound example 4-b 168 mg (0.24 mmol), palladium acetate 1.0 mg (2.0 mol%), SPhos in a pressure-resistant test tube reactor. 6 mg (4.0 mol%) was added and stirred for 30 minutes. Further, a base solution of tripotassium phosphate 145 mg (0.68 mmol) + polyethylene glycol-200 0.6 g / distilled water 1.2 ml was added, and the mixture was heated and stirred at 90 ° C. for 15 hours. 3 drops of iodobenzene were added, and 3 drops of (4 ′, 4 ′, 5 ′, 5 ′,-tetramethyl-1 ′, 3 ′, 2′-dioxaborolan-2′-yl) benzene were added for 6 hours. The mixture was heated and stirred at 90 ° C. for an hour. The reaction product was added to 100 ml of 90% aqueous methanol solution, and the slurry was collected by filtration and washed with 50 ml of 90% aqueous methanol solution and 50 ml of methanol. It dried under reduced pressure at 50 degreeC for 15 hours, and black solid was obtained.

  The obtained solid was refluxed and stirred for 1 hour in each solvent using 70 ml of methanol, 70 ml of acetone, and 70 ml of hexane, and filtered while heating to remove the dissolved substances of each solvent. Further, 70 ml of toluene was stirred under reflux for 1 hour and filtered while hot, and the filtrate was concentrated to 10 ml with an evaporator. The concentrated solution was put into 50 ml of methanol to make a slurry, filtered, and washed with 20 ml of methanol. It dried under reduced pressure at 50 degreeC for 16 hours, and obtained 168 mg (yield 97.0%) of conjugated polymer 3 shown to following formula (32) as black solid.

  About the obtained conjugated polymer 3, an elemental analysis and the measurement result of IR are shown below. These results confirmed that the conjugated polymer 3 has the structure of the formula (32).

Measurement results of elemental analysis

IR (KBr) (cm ⁻¹ ): ν 667, 759 (w), 811 (w), 946 (w), 1041 (m), 1153 (m), 1249 (m), 1292 (m), 1361 ( m), 1398 (m), 1457 (m), 1519, 1565 (m), 1700 (s), 1724 (m), 2858 (s), 2869 (s), 2925 (vs), 2956 (vs)

  As a result of measuring the molecular weight distribution of the obtained conjugated polymer 3 by the same method as in Example 1, it was confirmed that the weight average molecular weight of the conjugated polymer 3 was (Mw) 56,617.

The absorbance of the obtained conjugated polymer 3 was measured by the same method as in Example 1. As a result, the maximum absorption wavelength λ _max was 666.0 nm.

Table 1 shows the results of the weight average molecular weight and the maximum absorption wavelength measured under the above measurement conditions.

Example 4 [Conjugated Polymer 4]
The reaction was carried out under the same conditions except that polyethylene glycol-200 in Example 1 was changed to polyethylene glycol-300 to obtain conjugated polymer 4 having unit segments described in the above formula (30). About the obtained conjugated polymer 4, the weight average molecular weight Mw, the maximum absorption wavelength λ _max and the UV-visible spectrum were measured by the method described in Example 1, and the results of the weight average molecular weight Mw and the maximum absorption wavelength λ _max were obtained. It is shown in Table A.

Example 5 [Conjugated Polymer 5]
The reaction was carried out under the same conditions except that polyethylene glycol-200 in Example 1 was changed to polyethylene glycol-400 to obtain conjugated polymer 5 having a unit segment described in the above formula (30). About the obtained conjugated polymer 5, the weight average molecular weight Mw, the maximum absorption wavelength λ _max and the UV-visible spectrum were measured by the method described in Example 1, and the results of the weight average molecular weight Mw and the maximum absorption wavelength λ _max were obtained. It is shown in Table A.

Example 6 [Conjugated Polymer 6]
The reaction was conducted under the same conditions except that 130 mg (0.22 mmol) of Compound Example 1-b of Example 1 was replaced with 108 mg (0.22 mmol) of Compound Example 1-c, and 2.4 ml of toluene and water were changed to 4.8 ml. The conjugated polymer 6 having the unit segment described in the formula (30) was obtained. About the obtained conjugated polymer 6, the weight average molecular weight Mw, the maximum absorption wavelength λ _max and the UV-visible spectrum were measured by the method described in Example 1, and the results of the weight average molecular weight Mw and the maximum absorption wavelength λ _max were obtained. It is shown in Table A.

Example 7 [Conjugated Polymer 7]
The reaction was carried out under the same conditions except that polyethylene glycol-200 in Example 1 was changed to polypropylene glycol-300 to obtain conjugated polymer 7 having a unit segment described in the above formula (30). About the obtained conjugated polymer 7, the weight average molecular weight Mw, the maximum absorption wavelength λ _max and the UV-visible spectrum were measured by the method described in Example 1, and the results of the weight average molecular weight Mw and the maximum absorption wavelength λ _max were obtained. It is shown in Table A.

Example 8 [Conjugated Polymer 8]
The reaction was carried out under the same conditions except that polyethylene glycol-200 of Example 1 was changed to diethylene glycol (molecular weight = 106.12) to obtain a comparative conjugated polymer 8 having a unit segment described in the formula (30). . About the obtained comparative conjugated polymer 8, the weight average molecular weight Mw, the maximum absorption wavelength λ _max and the UV-visible spectrum were measured by the method described in Example 1, and the results of the weight average molecular weight Mw and the maximum absorption wavelength λ _max were obtained. Are shown in Table A.

Example 9 [Conjugated Polymer 9]
Since there is no polyethylene glycol commercially available product having a number average molecular weight of 500, a polyethylene glycol material having a number average molecular weight of about 500 was prepared by GPC measurement using polyethylene glycol-400 and polyethylene glycol-600. The reaction was carried out under the same conditions except that polyethylene glycol-200 of Example 1 was changed to this material to obtain a conjugated polymer 9 having a unit segment described in the above formula (30). About the obtained conjugated polymer 9, the weight average molecular weight Mw, the maximum absorption wavelength λ _max and the UV-visible spectrum were measured by the method described in Example 1, and the results of the weight average molecular weight Mw and the maximum absorption wavelength λ _max were obtained. It is shown in Table A.

Comparative Example 1 [Comparative Conjugated Polymer 1]
The reaction was carried out under the same conditions except that polyethylene glycol-200 in Example 1 was changed to polyethylene glycol-600 to obtain a comparative conjugated polymer 1 having a unit segment described in the above formula (30). About the obtained comparative conjugated polymer 1, the weight average molecular weight Mw, the maximum absorption wavelength λ _max and the UV-visible spectrum were measured by the method described in Example 1, and the results of the weight average molecular weight Mw and the maximum absorption wavelength λ _max were obtained. Table A shows the UV-visible spectrum of FIG.

Comparative Example 2 [Comparative Conjugated Polymer 2]
The reaction was carried out under the same conditions except that polyethylene glycol-200 in Example 1 was changed to polyethylene glycol-1000 to obtain comparative conjugated polymer 2 having a unit segment described in the above formula (30). About the obtained comparative conjugated polymer 2, the weight average molecular weight Mw, the maximum absorption wavelength λ _max and the UV-visible spectrum were measured by the method described in Example 1, and the results of the weight average molecular weight Mw and the maximum absorption wavelength λ _max were obtained. Are shown in Table A.

Comparative Example 3 [Comparative Conjugated Polymer 3]
The reaction was performed under the same conditions except that polyethylene glycol-200 of Example 1 was not added to the reaction system, to obtain a comparative conjugated polymer 3 having a unit segment described in the formula (30). About the obtained comparative conjugated polymer 3, the weight average molecular weight Mw, the maximum absorption wavelength λ _max and the UV-visible spectrum were measured by the method described in Example 1, and the results of the weight average molecular weight Mw and the maximum absorption wavelength λ _max were obtained. Table A shows the UV-visible spectrum of FIG.

Comparative Example 4 [Comparative Conjugated Polymer 4]
The reaction was carried out under the same conditions except that polyethylene glycol-200 of Example 2 was not added to the reaction system to obtain a comparative conjugated polymer 4 having a unit segment described in the formula (31). For the obtained comparative conjugated polymer 4, the weight average molecular weight Mw, the maximum absorption wavelength λ _max and the UV-visible spectrum were measured by the method described in Example 1, and the results of the weight average molecular weight Mw and the maximum absorption wavelength λ _max were obtained. Are shown in Table A.

Comparative Example 5 [Comparative Conjugated Polymer 5]
The reaction was carried out under the same conditions except that polyethylene glycol-200 of Example 3 was not added to the reaction system to obtain a comparative conjugated polymer 5 having a unit segment described in the above formula (32). About the obtained comparative conjugated polymer 5, the weight average molecular weight Mw, the maximum absorption wavelength λ _max and the UV-visible spectrum were measured by the method described in Example 1, and the results of the weight average molecular weight Mw and the maximum absorption wavelength λ _max were obtained. Are shown in Table A.

  Table A shows the weight average molecular weight and the maximum absorption wavelength of the conjugated polymers obtained in Examples 1 to 9 and the comparative conjugated polymers obtained in Comparative Examples 1 to 5. In the table, thienothiophene is abbreviated as TTP, and benzodithiophene as BDT.

  Conjugated polymer obtained by Suzuki polymerization reaction using polyalkylene glycol with an average molecular weight of less than 600 as a polymerization accelerator absorbs in a higher degree of polymerization and longer wavelength region than a comparative conjugated polymer without using a polymerization accelerator. A polymer with a band was obtained. This tendency was particularly remarkable when polyethylene glycol having a molecular weight of 200 to 300 was used.

  In the production of a conjugated polymer having thienothiophene-benzodithiophene as a unit segment of the present invention, a polyalkylene glycol having a specific molecular weight range is used as a polymerization accelerator, and a Suzuki polymerization reaction is performed to increase the molecular weight, thereby increasing the wavelength. A conjugated polymer can be obtained. Further, the conjugated polymer having thienothiophene-benzodithiophene as a unit segment of the present invention exhibits a low band gap, and further becomes a suitable photoelectric conversion element by making it into an element, and can be used as an effective organic thin film solar cell. it can.

Claims (6)

Following formula (1)
[In Formula (1),
R ¹ represents a hydrogen atom, a linear or branched alkyl group, an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a group which is partially or completely substituted with fluorine. A chain or branched alkyl group, an aralkyl group partially or fully substituted with fluorine, or an aryl group partially or fully substituted with fluorine,
X is a hydrogen atom, a halogen atom, or a linear or branched alkyl group,
Y is a halogen atom. ]
A thienothiophene derivative represented by:
Following formula (2)
[In Formula (2),
R ² is the same or different and has a hydrogen atom, a linear or branched alkyl group, an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. May be a heteroaryl group, an alkoxy group, an ester group, an amide group, a linear or branched alkyl group that is partially or fully substituted with fluorine, or an aralkyl group that is partially or fully substituted with fluorine, or fluorine. An aryl group partially or fully substituted, or a heteroaryl group partially or fully substituted with fluorine,
R ³ is the same or different and is a boronic acid residue or a boronic acid ester residue obtained by reacting a diol or alcohol with boric acid. ]
A benzodithiophene derivative represented by the following formula: Suzuki polymerization reaction in the presence of a polyalkylene glycol having a number average molecular weight of less than 600 or a derivative thereof:
Following formula (3)

[In Formula (3),
R ¹ represents a hydrogen atom, a linear or branched alkyl group, an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a group which is partially or completely substituted with fluorine. A chain or branched alkyl group, an aralkyl group partially or fully substituted with fluorine, or an aryl group partially or fully substituted with fluorine,
X is a hydrogen atom, a halogen atom, or a linear or branched alkyl group,
R ² is the same or different and has a hydrogen atom, a linear or branched alkyl group, an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. It may be a heteroaryl group, an alkoxy group, an ester group, an amide group, a linear or branched alkyl group partially or fully substituted with fluorine, an aralkyl group partially or fully substituted with fluorine, or a fluorine. A partially or fully substituted aryl group or a heteroaryl group partially or fully substituted with fluorine. ]
The manufacturing method of the conjugated polymer which makes the unit segment the thienothiophene-benzodithiophene represented by these.   The method for producing a conjugated polymer according to claim 1, wherein the polyalkylene glycol or a derivative thereof has a number average molecular weight of 100 to 500. In the unit segment represented by the formula (3), R ¹ is a linear or branched alkyl group having 1 to 10 carbon atoms, and R ² is a linear or branched alkyl group having 1 to 18 carbon atoms or carbon. The method for producing a conjugated polymer according to claim 1 or 2, which is a linear or branched alkylheteroaryl group of 1 to 10, and X is hydrogen or a fluorine atom.   The method for producing a conjugated polymer according to any one of claims 1 to 3, wherein the Suzuki polymerization is performed in a solvent in the presence of a base, a palladium catalyst, and an organic phosphorus compound.   The method for producing a conjugated polymer according to any one of claims 1 to 4, wherein the obtained conjugated polymer has a polystyrene-equivalent weight average molecular weight of 30,000 to 1,000,000.   The photoelectric conversion element using the conjugated polymer obtained with the manufacturing method in any one of Claims 1-5.