JP2018095692A - Conjugated polymer compound containing novel sulfanyl-substituted dithienylthienopyrazine derivative structure as monomer segment, method for producing the same and photoelectric conversion element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conjugated polymer compound suitable for photoelectric conversion elements for solar cells, and a method for producing a low band gap conjugated polymer compound containing dithienylthienopyrazine derivatives.SOLUTION: The present invention provides a conjugated polymer compound containing a monomer segment represented by formula (1) [R's independently represent a substituted/unsubstituted linear/branched alkyl group, a substituted/unsubstituted aryl group or a substituted/unsubstituted aralkyl group; A is a segment derived from a polycyclic aromatic compound having a carbon skeleton, or a segment derived from a heterocyclic aromatic compound containing (a) hetero atoms].SELECTED DRAWING: None

Description

  The present invention relates to a conjugated polymer compound containing at least a segment derived from a thienopyrazine derivative that is suitably used for a photoelectric conversion element, a production method thereof, and an application thereof.

  The condensed ring system [3,4-b] pyrazine derivative is an important compound that has been synthesized as a research target in the field of medicine and agricultural chemicals for the purpose of solubility and modification of the active site. In recent years, in the field of functional materials science, thienopyrazine derivatives and quinoxaline derivatives condensed with a pyrazine ring are considered to be usable as monomers of low band gap (Eg <1.5 eV) conjugated polymer compounds. .

  Decreasing the band gap of conjugated polymer compounds facilitates electron transition from charged to conductor and leads to increased carriers, so these polymers have improved conductivity and long wavelength shifts in absorption and emission spectra. Etc. have good characteristics.

  As the monomer of the low band gap conjugated polymer compound, many heterocyclic compounds are used, and examples thereof include thiophene, thienothiophene, thienopyrazine, benzodithiophene, and carbazole.

  Many reports have been made on low band gap conjugated polymers using thienopyrazine as a segment, and in recent years, their high light resistance and electron acceptability have attracted attention. However, since a condensed ring unit such as thienopyrazine is synthesized by a reaction of an o-aromatic diamine and an α-diketone, derivatives that can be synthesized are limited. Therefore, development of thienopyrazine having various substituents and development of a low band gap conjugated polymer compound containing a monomer segment (repeating unit) containing the thienopyrazine derivative structure are desired.

  JP-A-2006-079291 (Patent Document 1) discloses a conductive thienopyrazine conjugated polymer compound containing at least a monomer segment represented by the formula (I). Although a structure in which a sulfanylphenyl group is substituted on the thienopyrazine skeleton is disclosed, a structure in which a sulfanyl group is substituted on the thienopyrazine skeleton is not described. Further, there is no description regarding a segment derived from a dithienylthienopyrazine derivative in which a thiophene ring is bonded to a thienopyrazine skeleton.

  JP 2012-56991 A (Patent Document 2) discloses a conductive thienopyrazine copolymer composition having a repeating unit represented by the formula (II). However, Patent Document 2 does not describe a structure in which a thienopyrazine skeleton is substituted with a sulfanyl group.

  A condensed ring unit such as a general thienopyrazine is synthesized by the reaction of an o-aromatic diamine and an α-diketone. However, there is a problem that derivatives that can be synthesized depend on the structure of the α-diketone. As a method for synthesizing a thienopyrazine derivative different from the above, a substitution reaction of a dithienylthienopyrazine derivative having a leaving group with an alcohol or an amine has been reported (J. Org. Chem. 2013, 78, 5453-5462: Non-patent document 1). However, there is no description of a dithienylthienopyrazine derivative having a sulfanyl group.

  In recent years, application development of these low band gap conjugated polymer compounds such as charge transport materials for organic EL devices, organic thin film transistor materials, and photoelectric conversion materials has been studied.

  A photoelectric conversion material is a material that can convert light energy into electrical energy by using a photoelectric effect. When the photoelectric conversion material is irradiated with light, the electrons bound to the atoms in the material can move freely by light energy, thereby generating free electrons and free electron holes. Thus, these free electrons and holes are efficiently separated and energy can be extracted continuously. Utilizing such characteristics, it has been applied to various uses, 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.

  In general, solar cells have been studied for use outdoors. However, organic materials such as conjugated polymer compounds absorb light in the visible light region, so indoors such as fluorescent lamps and LED light sources are used. Matching with lighting is also good. Therefore, the photoelectric conversion element using these can also be applied as a solar cell for indoor use.

  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. In addition to the 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 groups and ligands, Furthermore, studies are being made on the efficiency of reactions by changing external parameters such as reaction media.

  In particular, a thienothiophene-benzodithiophene conjugated polymer compound 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 2) In such a polymerization reaction of a low band gap conjugated polymer compound, increasing the degree of polymerization of the product is important for annealing by making a device and improving solar absorption efficiency. is there.

  In the synthesis of many high-performance p-type organic semiconductor materials currently reported, including the thienothiophene-benzodithiophene conjugated polymer compound (PTB-7) in Non-Patent Document 2, Stille coupling reaction is used. It has been. Since this coupling reaction uses a monomer having a tin functional group with strong environmental toxicity, it is considered that industrial large-scale production is difficult from the viewpoint of safety and environment. For this reason, in order to industrialize a low band gap conjugated polymer compound, a highly safe production method with lower environmental toxicity than the conventional method using Stille coupling reaction is desired.

Japanese Patent Laid-Open No. 2006-79291 JP 2012-56991 A

J. et al. Org. Chem. 2013, 78, 5453-5462 Adv. Mater. 2010, 22, 1-4

  The present invention is a conjugated polymer compound having a low band gap suitable for a photoelectric conversion element used for an organic thin film solar cell application, and does not use organic tin, has a low environmental burden and high work safety. It is an object of the present invention to provide a method for producing a low band gap conjugated polymer compound comprising a segment derived from a thienyl thienopyrazine derivative in at least a monomer segment.

  The present invention provides a conjugated polymer compound containing a segment derived from a dithienylthienopyrazine derivative having a low band gap, which is useful as an organic semiconductor material, a photoelectric conversion material or the like, at least in a monomer segment. The present invention further provides a method for producing the conjugated polymer compound, which has a low environmental impact and high industrial utility value.

That is, the present invention provides the following conjugated polymer compound and production method.
[1]: Formula (1) below,
(1)
[In Formula (1), R ¹ may be the same or different, and may be a linear or branched alkyl group which may have a substituent, an aryl group which may have a substituent, or An aralkyl group which may have a substituent,
A is a segment derived from a polycyclic aromatic compound comprising a carbon skeleton, or a segment derived from a heterocyclic aromatic compound containing a hetero atom. ] The conjugated polymer compound containing the monomer segment represented by this.
[2]: In the above formula (1), A is a segment derived from a carbazole derivative, the following formula (2),
(2)
[In Formula (2), R ¹ is as defined above, and R ² is a linear or branched alkyl group which may have a substituent, or an aralkyl group which may have a substituent. , An aryl group which may have a substituent, and a heteroaryl group which may have a substituent. ]
Or, in the formula (1), A is a segment derived from a fluorene derivative, the following formula (3),
(3)
[In Formula (3), R ¹ is as defined above, and R ³ may be the same or different and may have a linear or branched alkyl group or substituent. An aralkyl group which may have a substituent, an aryl group which may have a substituent, and a heteroaryl group which may have a substituent. The conjugated high molecular compound which is a monomer segment represented by this is preferable.
[3]: The present invention also provides a photoelectric conversion element comprising the conjugated polymer compound of the present invention.
[4]: The present invention also provides an organic thin-film solar cell including the photoelectric conversion element of the present invention.
[5]: The present invention also provides the following formula (4),
(4)
[In Formula (4), R ¹ is as defined above, and X is fluorine, chlorine, bromine or iodine. A halogenated thienopyrazine derivative monomer;
Following formula (5),
R ⁴ -A-R ⁴ (5)
[In Formula (5), A is a segment derived from a polycyclic aromatic compound comprising a carbon skeleton, or a segment derived from a heterocyclic aromatic compound containing a hetero atom, and R ⁴ is boronic acid or an ester thereof. Is a residue from In the presence of a palladium catalyst and an organophosphorus compound, a Suzuki polymerization reaction is performed in the presence of a palladium catalyst and an organophosphorus compound in a reaction solvent, the following formula (1),
(1)
[In formula (1), R ¹ is as defined above, and A is a segment derived from a polycyclic aromatic compound comprising a carbon skeleton or a segment derived from a heterocyclic aromatic compound containing a hetero atom. is there. ] The manufacturing method of the conjugated polymer compound containing the monomer segment represented by this is provided.
[6]: The present invention also provides a raw material for a halogenated dithienylthienopyrazine derivative that is an intermediate of a conjugated polymer compound, represented by the following formula (6):
(6)
[In formula (6), R ¹ has the same meaning as described above. ] The dithienyl thienopyrazine derivative which has a sulfanyl group represented by these is provided.
[7]: The present invention also provides the following formula (7),
(7)
[In Formula (7), R ⁵ may be the same or different and is a halogen atom, a sulfonate group, a tosyl group, a mesyl group or a nitro group. A dithienylthienopyrazine derivative represented by:
Following formula (8),
R ¹ -SH (8)
[In Formula (8), R ¹ has the same meaning as described above. A substitution reaction in the presence of a base in a reaction solvent, the following formula (6),
(6)
[In formula (6), R ¹ has the same meaning as described above. ] The manufacturing method of the dithienyl thienopyrazine derivative which has a sulfanyl group represented by these is provided.

  According to the present invention, it is possible to provide a novel conjugated polymer compound having at least a segment derived from dithienyl thienopyrazine having a sulfanyl group and having high light resistance, high solubility and low band gap. In addition, the conjugated polymer compound of the present invention is useful as a conductive polymer, is optimal as a polymer used for a conductive material, and is particularly excellent in electron donating properties, so that it can be used as a p-type organic semiconductor material. Is preferred

  The conjugated polymer compound of the present invention is characterized by having a thiophene structure between a thienopyrazine derivative structure and an A segment (for example, a segment derived from a carbazole derivative or a segment derived from a fluorene derivative). Such a structure is expected to extend the π-conjugated system, thereby improving light stability and increasing light resistance.

  In the present invention, the conjugated polymer compound includes a dithienylthienopyrazine derivative, for example, a carbazole derivative or a fluorene derivative in the presence of a palladium catalyst and an organic phosphorus compound (particularly, an organic phosphorus compound having a high electron donating group). Can be produced by a Suzuki polymerization reaction. For this reason, compared with the conventional Stille coupling which discharges the waste liquid containing organic tin with high environmental toxicity, the safe manufacturing work which does not contain organotin is possible, and manufacture which reduced environmental burden is performed. Can do.

  In addition, according to the present invention, it is possible to provide a production method that facilitates optimization of substituents by the structure of thiol using a sulfanyl-substituted dithienylthienopyrazine derivative for the reaction.

It is a schematic explanatory drawing of the photoelectric conversion element (forward type photoelectric conversion element (A) and reverse type photoelectric conversion element (B)) using a conjugated polymer compound. It is a graph which shows the ultraviolet visible spectrum of the conjugated polymer compounds 1-4 and the comparative conjugated polymer compound 1.

  Hereinafter, although the form for implementing this invention is demonstrated in detail, the scope of the present invention is not limited to these forms.

Hereinafter, the conjugated polymer compound comprising a monomer segment containing at least a segment derived from the sulfanyl-substituted dithienylthienopyrazine derivative of the present invention will be described in detail. However, the segment of the conjugated polymer compound of the present invention indicates a partial structure derived from the raw material monomer used in the polymerization reaction, and the monomer segment indicates a repeating unit of the conjugated polymer compound composed of the segments. In the present specification, the term “sulfanyl group” means an R ¹ S— group. Here, R ¹ has the same definition as above.

(Monomer segment including a segment derived from a dithienyl thienopyrazine derivative having a sulfanyl group)
The monomer segment including a segment derived from thienopyrazine, which is a segment of the conjugated polymer compound of the present invention, is represented by the following formula (1).
(1)
[In Formula (1), R ¹ may be the same or different, and may be a linear or branched alkyl group which may have a substituent, an aryl group which may have a substituent, or An aralkyl group which may have a substituent, A is a segment derived from a polycyclic aromatic compound composed of a carbon skeleton or a segment derived from a heterocyclic aromatic compound containing a hetero atom. ].

  Segment A of the conjugated polymer compound of the present invention represents a segment derived from a polycyclic aromatic compound having a carbon skeleton or a segment derived from a heterocyclic aromatic compound containing a hetero atom. Examples of the segment derived from a polycyclic aromatic compound having a carbon skeleton include a segment derived from naphthalene, azulene, and fluorene. A segment derived from a heterocyclic aromatic compound containing a hetero atom includes a heterocyclic skeleton containing a sulfur atom or a nitrogen atom, such as a thiophene ring, a thiazole ring, a thiadiazole ring, a carbazole ring, or a pyrrole ring. Examples include segments derived from aromatic compounds. Among these, particularly when the conjugated polymer compound of the present invention is used as a photoelectric conversion material, the segment A is a segment derived from a fluorene derivative having a high electron donating property, carbazole, from the viewpoint of photoelectric conversion efficiency and electron donating property. A segment derived from a derivative is more preferred.

  As a preferable monomer segment structure of the conjugated polymer compound, Formula (2) or Formula (3) can be shown.

(2)
[In formula (2), R ¹ and R ² are as defined above. ]

(3)
[In the formula (3), R ¹ and R ³ are as defined above. ]

  The conjugated polymer compound of the present invention is formed by the continuous monomer segments. The number of monomer segments varies depending on the molecular weight. When the number of monomer segments of the formula (1) is p, the number of monomer segments of the formula (2) is q, and the number of monomer segments of the formula (3) is r, the conjugated polymer compound of the present invention has the formula ( 1a), Formula (2a), and Formula (3a).

(1a)
[In Formula (1a), R ¹ and A are as defined above. ]

(2a)
[In the formula (2a), R ¹ and R ² are as defined above. ]

(3a)
[In formula (3a), R ¹ and R ³ are as defined above. ]

  In the formula (1a), the formula (2a) and the formula (3a), p, q and r are preferably 5 to 300. When p, q, and r are less than 5, the π-electron conjugated system does not expand sufficiently, so that sufficient solar light absorption efficiency cannot be obtained. Moreover, when p, q, and r exceed 300, since solubility will fall, there exists a possibility that preparation of a uniform photoelectric converting layer may become difficult. Each of p, q and r is more preferably 7 to 200, and still more preferably 8 to 180.

  Formula (1) (hereinafter “Formula (1)” also means Formula (1a). In other words, the mode shown by Formula (1a) is also included. Similarly, the case of “Formula (2)” Means also the formula (2a). Furthermore, in the case of “formula (3)”, the conjugated polymer compound containing the monomer segment represented by the formula (3a) has a low band gap property, It has characteristics such as high carrier mobility and 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. From the above viewpoint, the weight average molecular weight of the conjugated polymer compound is preferably 5,000 to 300,000, more preferably 7,000 to 200,000, still more preferably 8,000 to 180,000.

  The segment A of the formula (1) is a segment derived from a polycyclic aromatic compound having a carbon skeleton or a segment derived from a heterocyclic aromatic compound containing a hetero atom. Specific examples of the segment A include segments derived from fluorene derivatives, benzodithiophene derivatives, and carbazole derivatives. Among these, when the conjugated polymer compound of the present invention is used as a photoelectric conversion material, the segment A can be selected from a segment derived from a fluorene derivative or a segment derived from a carbazole derivative from the viewpoint of electron donating properties.

More specific examples of the segment A are shown below, but are not limited thereto. However, R ^a represents a linear or branched alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. It is a heteroaryl group which may have.

As the segment A, the following examples are more preferable.

The linear or branched alkyl group in R ¹ in the above formula (1), formula (2), and formula (3) is a linear or branched alkyl group having 1 to 18 carbon atoms, or 3 to 3 carbon atoms. 18 alicyclic alkyl groups are mentioned.
Specific examples of the linear or branched alkyl group having 1 to 18 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-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, lauryl group or stearyl group. A straight-chain or branched alkyl group having 1 to 10 carbon atoms is preferable, and a branched alkyl group having 3 to 10 carbon atoms is particularly preferable, i-butyl group, sec-butyl group, t-butyl. A group, i-pentyl group or 2-ethylhexyl group is particularly preferred.
Examples of the alicyclic alkyl group having 3 to 18 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group.

The aryl group which may have a substituent in R ¹ in the above formula (1), formula (2), and formula (3) is, for example, an aryl group having 6 to 18 carbon atoms, specifically phenyl. Group, naphthyl group and the like.
The aralkyl group which may have a substituent in R ¹ in the above formula (1), formula (2), and formula (3) is, for example, an aralkyl group having 7 to 19 carbon atoms, specifically benzyl. Group, phenylethyl group or α, α'-dimethylbenzyl group.

  Examples of the substituent that the alkyl group may have include an alkoxy group, a haloalkyl group, an aryl group, a heteroaryl group, and a hydroxyl group.

  Examples of the substituent that the aryl group or aralkyl group may have include a linear or branched alkyl group, an alkoxy group, a haloalkyl group, an aryl group, a heteroaryl group, a halogen atom, and a hydroxyl group.

  The alkyl group of the substituent is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, and more specifically, a methyl group, an ethyl group, an n-propyl group, or an i-propyl group. , N-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-pentyl group, i-pentyl group, neo-pentyl group, n-hexyl group, n-heptyl group, n-octyl group , 2-ethylhexyl group, n-decyl group and the like. In particular, a linear or branched alkyl group having 1 to 8 carbon atoms is preferable, and i-butyl group, sec-butyl group, t-butyl group, i-pentyl group and 2-ethylhexyl group are more preferable.

  Examples of the alkoxy group of the substituent include an alkoxy group having 1 to 18 carbon atoms, specifically, a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i- Examples include butoxy group, sec-butoxy group, t-butoxy group, n-pentyloxy group, neo-pentyloxy group, n-hexyloxy group, n-heptyloxy group, and n-octyloxy group.

The haloalkyl group of the substituent is an alkyl group to which a halogen atom (F, Cl, Br, I) is added, and examples of the alkyl group include the alkyl groups having 1 to 18 carbon atoms. As the halogen atom, fluorine is preferred. More specifically, perfluoroalkyl groups exemplified by CF ₃ group, C ₂ F ₅ group, n-C ₃ F ₇ group, n-C ₄ F ₉ group, n-C ₇ F ₁₅ group and the like (C _m F _{2m + 1} -group (m = 1 to 18)); a partial fluoroalkyl group exemplified by CHF ₂ group, CH ₂ F group, CH (CF ₃ ) ₂ group and the like.

  Examples of the aryl group for the substituent include an aryl group having 6 to 18 carbon atoms, and specific examples include a phenyl group and a naphthyl group. Examples of the heteroaryl group for the substituent include heteroaryl groups having 4 to 10 carbon atoms, and specific examples include a thienyl group, a pyrrolyl group, a furyl group, and a pyridyl group.

R ² in the formula (2) may be the same or different and may be a linear or branched alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Examples thereof include an aryl group which may have a group and a heteroaryl group which may have a substituent. From the viewpoint of improving solubility, a linear or branched alkyl group which may have a substituent is preferable.

  Examples of the alkyl group which may have a substituent include linear or branched alkyl groups having 1 to 18 carbon atoms. Specific examples include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-pentyl group, and neo-pentyl group. N-hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-decyl group, lauryl group or stearyl group. Examples of the alicyclic alkyl group having 3 to 18 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group.

  Further, from the viewpoint of improving the solubility and improving the charge transport property by improving the face-on orientation of the polymer, a branched alkyl group is more preferable. In particular, it is preferably a branched alkyl group having 1 to 18 carbon atoms, specifically, i-butyl group, sec-butyl group, t-butyl group, 1-propylbutyl group, i-pentyl group, neo-pentyl group, 1-methylpentyl group, 2-ethylpentyl group, 1-butylpentyl group, 2-ethylhexyl group, 1-pentylhexyl group, 2-propylheptyl group, 1-hexylheptyl group, t-octyl group 1-heptyloctyl group, 1-octylnonyl group, 1-propyldecyl group, 1-methylundecyl group, 1-ethyldodecyl group and the like.

R ³ in the formula (3) may be the same or different and may be a linear or branched alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent Examples thereof include an aryl group which may have a group and a heteroaryl group which may have a substituent. From the viewpoint of improving solubility and the morphology in the device, it is more preferably a linear or branched alkyl group which may have a substituent.

  Examples of the alkyl group which may have a substituent include linear or branched alkyl groups having 1 to 18 carbon atoms. Specific examples include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-pentyl group, and neo-pentyl group. N-hexyl group, n-heptyl group, n-octyl group, n-decyl group, lauryl group or stearyl group, 1-methylpentyl group, 2-ethylpentyl group, 1-butylpentyl group, 2-ethylhexyl group, 1-pentylhexyl group, 2-propylheptyl group, 1-hexylheptyl group, t-octyl group, 1-heptyloctyl group, 1-octylnonyl group, 1-propyldecyl group, 1-methylundecyl group, 1- An ethyldodecyl group is mentioned. Examples of the alicyclic alkyl group having 3 to 18 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group.

The aralkyl group which may have a substituent in R ² in Formula (2) or R ³ in Formula (3) is, for example, an aralkyl group having 7 to 19 carbon atoms. Examples include a benzyl group, a phenylethyl group, and an α, α′-dimethylbenzyl group.

The aryl group which may have a substituent in R ² in formula (2) or R ³ in formula (3) is, for example, an aryl group having 6 to 18 carbon atoms, specifically, A phenyl group, a naphthyl group, etc. are mentioned.

Examples of the heteroaryl group which may have a substituent in R ² in Formula (2) or R ³ in Formula (3) include a heteroaryl group having 4 to 10 carbon atoms, Specific examples include thienyl group, pyrrolyl group, furyl group, pyridyl group and the like.

  Examples of the substituent that the alkyl group may have include an alkoxy group, a haloalkyl group, an aryl group, a heteroaryl group, and a hydroxyl group, as in paragraph 0040.

  As the substituents that the above aralkyl group, aryl group, and heteroaryl group may have, a linear or branched alkyl group, alkoxy group, haloalkyl group, hydroxyl group, halogen atom (F, Cl, Br, I) and the like can be exemplified.

(Method for producing conjugated polymer compound)
The method for producing the conjugated polymer compound of the present invention comprises:
Reaction step 1) A sulfanyl group is added to a dithienylthienopyrazine having a leaving group (R ⁵ ) such as a halogen atom, a sulfonate group, a tosyl group, a mesyl group, or a nitro group represented by the above formula (7). Introducing a sulfanyl-substituted dithienylthienopyrazine derivative represented by the formula (6),
Reaction step 2) a step of halogenating a dithienylthienopyrazine derivative having a sulfanyl group using a halogenating agent to obtain a halogenated dithienylthienopyrazine derivative represented by the above formula (4);
Reaction step 3) A halogenated dithienylthienopyrazine derivative and a boronated monomer (formula (5); hereinafter referred to as “A monomer” in the description), a palladium catalyst and phosphorus coordination A step of performing a Suzuki polymerization reaction in the presence of a child to obtain a conjugated polymer compound represented by the formula (1),
Consists of.

  In the production method described above, by using a carbazole derivative as the A monomer, a production method of the conjugated polymer compound represented by the formula (2) can be obtained. Moreover, it can be set as the manufacturing method of the conjugated polymer compound represented by said Formula (3) by using a fluorene derivative as A monomer.

The above-described method for producing a conjugated polymer compound of the present invention is performed according to the following reaction scheme (9a), reaction scheme (9b), and reaction scheme (9c).
[In the formulas (9a), (9b) and (9c), R ¹ and R ⁵ , A, X, p are as defined above, and R ⁴ is a residue from boronic acid or an ester thereof. is there. ]

The reaction scheme (9a), which is the first step of the production method of the present invention, will be described below.
As a starting material, a dithienylthienopyrazine derivative having a leaving group uses 5,7-bis (2-thienyl) thieno [3,4-b] pyrazine-2,3 (1H, 4H) -dione, for example, J. et al. Org. Chem. 2013, 78, 5453-5462. It can synthesize | combine by the well-known method of description.

R ⁵ in the above formula (9a) represents a halogen atom (F, Cl, Br, I), a sulfonate group such as a trifluoromethanesulfonate group or a nonafluorobutanesulfonate group, a tosyl group, a mesyl group, or a nitro group. It can be illustrated. Among them, a sulfonate group is preferable from the viewpoint of having a high leaving group performance, and a trifluoromethanesulfonate group is particularly preferable.

As a first step of the production method of the present invention, a sulfanyl group introduction reaction (substitution reaction to a sulfanyl group), the dithienyl thienopyrazine derivative having the leaving group (R ⁵ ) is present in a solvent in the presence of a base. By reacting the thiol derivative, a sulfanyl-substituted dithienylthienopyrazine derivative represented by the formula (6) is obtained.

  Examples of the thiol derivatives used for the introduction reaction of the sulfanyl group include butanethiol, octanethiol, dodecanethiol, octadecanethiol, 2-propanethiol, t-butylmercaptan, 2-ethylhexanethiol, 2-diisopropylaminoethanethiol, benzene Examples include thiol, 4-tert-butylbenzenethiol, 4- (trifluoromethyl) benzenethiol, pentafluorobenzenethiol and the like.

  The reaction solvent used for the introduction reaction of the sulfanyl group is not particularly limited as long as it can dissolve the reaction raw material, but it is preferable to use a reaction solvent subjected to dehydration treatment.

  The base used for the introduction reaction of the sulfanyl group is not particularly limited, and examples thereof include butyl lithium, phenyl lithium, lithium diisopropylamide, lithium bistrimethylsilylamide, sodium hydride, calcium hydride and the like.

The reaction scheme (9b) which is the second stage of the production method of the present invention will be described. In the reaction scheme (9b), halogenation of a dithienylthienopyrazine derivative having a sulfanyl group as a starting material is performed. The dithienyl thienopyrazine derivative used in this reaction has the following formula (6),
(6)
[In Formula (6), R ¹ has the same meaning as described above. ]
It is represented by

  Specific examples of the sulfanyl-substituted dithienylthienopyrazine derivative represented by the formula (6) are shown below. The derivatives of the present invention are not limited to these.

  According to the reaction scheme (9a), a sulfanyl-substituted dithienyl thienopyrazine derivative is obtained. The obtained sulfanyl-substituted dithienylthienopyrazine derivative is subjected to a halogenation reaction using a general halogenating agent according to the reaction scheme (9b). A known halogenating agent can be appropriately selected as the halogenating agent. Specific examples of the halogenating agent include N-fluorobenzenesulfonimide, N-bromosuccinimide, dibromoisocyanuric acid, N-iodosuccinimide, 1,3-diiodo-5,5′-dimethylhydantoin, potassium iodide / periodate Examples include potassium acid and copper iodide.

The halogenated dithienylthienopyrazine derivative used in the present invention has the following formula (4),
(4)
[In formula (4), R ¹ and X are as defined above. ].

  Specific examples of the halogenated dithienylthienopyrazine derivative represented by the formula (4) are shown below. Note that the derivatives of the present invention are not limited to these.

  Reaction scheme (9c), which is the third step of the production method of the present invention, is boronated with the halogenated dithienylthienopyrazine derivative obtained above and a boronic acid or its ester represented by the formula (5). Represents a step of obtaining a conjugated polymer compound by performing a Suzuki polymerization reaction using the monomer A. More specifically, Suzuki polymerization reaction of a halogenated thienopyrazine derivative (4) and an A monomer (5) boronated with boronic acid or an ester thereof in the presence of a palladium catalyst and an organophosphorus compound and a base, A conjugated polymer compound is produced.

Here, the A monomer boronated with boronic acid or an ester thereof, as described above, has the following general formula:
R ⁴ -A-R ⁴ (5)
[In formula (5), A and R ⁴ are as defined above. ]
It is represented by

R ⁴ is a residue from a boronic acid, or a residue from a boronic acid ester obtained by reacting a boronic acid with a diol or monoalcohol. More specifically, R ⁴ represents boron, diols having 1 to 7 carbon atoms such as pinacol, catechol, neopentyl glycol, 1,2-ethanediol, 1,3-propanediol, methanol, ethanol, isopropanol, t -A boron functional group bonded to an alcohol having a linear or branched alkyl group having 1 to 10 carbon atoms such as butanol.

  As the residue of the boronic ester, a boronic ester residue composed of a known diol or monoalcohol and boron can be used. Examples thereof include groups represented by the following formulas (a) to (e).

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

  In the boron functionalization reaction to obtain the A monomer of formula (5) from the halide of A, in order to introduce the boronic acid ester group (c), 2-isopropoxy-4,4,5,5-tetramethyl In the case of introducing boronic ester group (e) using -1,3,2-dioxaborolane, 2-isopropoxy-4,4,6-trimethyl-1,3,2-dioxaborinane (manufactured by Tokyo Chemical Industry Co., Ltd.) ) Etc. can be used.

A carbazole derivative boronated with boronic acid or an ester thereof, which is a preferable A monomer, is represented by the following formula (11). Such a carbazole derivative can be synthesized by various known methods.
(11)
[In Formula (11), R ² may have a linear or branched alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. An aryl group or an optionally substituted heteroaryl group, R ⁴ is a residue from a boronic acid or an ester thereof. ]
A linear or branched alkyl group which may have a substituent of R ² in formula (11), an aralkyl group which may have a substituent, an aryl group which may have a substituent Or a heteroaryl group which may have a substituent is a linear or branched alkyl group which may have a substituent of formula (2), or an aralkyl group which may have a substituent Specific examples of the substituent are the same as the aryl group which may have a substituent or the heteroaryl group which may have a substituent. R ⁴ has the same definition as R ⁴ in formula (5).

The carbazole derivative (11), which is a preferred example of the A monomer of the present invention, has, for example, 2,7-dibromo-9-H-carbazole (manufactured by Tokyo Chemical Industry) as a starting material according to the following formula (12A) lower, by reacting a compound having a tosyl group ^{(Ts) (R 2 -OTs)} , it may be conveniently synthesized. Alternatively, according to the following formula (12B), 2,7-dibromo-9-H-carbazole (manufactured by Tokyo Chemical Industry) is used as a starting material and reacted with an organic halide (R ² -X ^a ) in the presence of a base and copper. Thus, it can be easily synthesized.

[In Formula (12A) and Formula (12B), R ² and R ⁴ are as defined above, Ts represents a tosyl group, and X ^a represents a halogen atom such as fluorine, chlorine, bromine or iodine. ]

  Specific examples of the carbazole derivative represented by the formula (11) are shown below. Note that the derivatives of the present invention are not limited to these.

A preferred fluorene derivative boronated with boronic acid or an ester thereof, which is a preferable A monomer, is represented, for example, by the following formula (13). These derivatives can be synthesized by various known methods.
(13)
[In Formula (13), R ³ and R ⁴ are as defined above. ]
Specific examples of the substituent for the alkyl group, aralkyl group, aryl group, and heteroaryl group of R ³ are the same as the alkyl group, aralkyl group, aryl group, and heteroaryl group of formula (2). Wherein ^{R 4} is defined the same as ^{R 4} of formula (5).

The fluorene derivative (13), which is a suitable example of the A monomer of the present invention, is prepared from 2,7-dibromofluorene (manufactured by Tokyo Chemical Industry) as a starting material according to the following formula, for example, and an organic halide (R ³ — It can be easily synthesized by reacting with X ^a ).

(14)
[In the formula (14), R ³ , R ⁴ and X ^a are as defined above. ]

  Specific examples of the fluorene derivative represented by the formula (13) are shown below. Note that the derivatives of the present invention are not limited to these.

  Specific examples of the compound having a tosyl group in the reaction formula (12A) include butyl-p-toluenesulfonate, t-butyl-p-toluenesulfonate, heptyl-p-toluenesulfonate, 9-heptadecane- Alkyl tosylate such as p-toluene sulfonate, aralkyl tosylate such as benzyl-p-toluene sulfonate, 2-phenylethyl-p-toluene sulfonate, 2-bromophenyl tosylate, p-toluene sulfone Examples include aryl tosylates such as phenyl acid, heteroaryl tosylates such as pyridin-2-yl tosylate and pyridin-3-yl tosylate.

  Specific examples of the organic halides in the reaction formula (12B) and the reaction formula (14) include halogenated alkyl compounds such as 1-bromooctane and 1-bromodecane, and halogenated aralkyl compounds such as bromomethylbenzene and chloromethylbenzene. Halogenated aryl compounds such as iodobenzene and bromobenzene, and halogenated heteroaryl compounds such as 2-bromothiophene and 2-chlorothiophene.

Examples of the palladium catalyst used in the reaction scheme (9c) 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, tris (dibenzylideneacetone) dipalladium and the like are preferably used from the viewpoint of polymerizability.

  The amount of the palladium catalyst used in the reaction scheme (9c) is not particularly limited as long as the Suzuki polymerization reaction proceeds. For example, with respect to 1 mol of the halogenated dithienyl thienopyrazine derivative, 0.001 mol% to It is 10.0 mol%, preferably 0.01 mol% to 5.0 mol%, more preferably 0.1 mol% to 3.0 mol%. If it is less than 0.001 mol%, the reaction may not be completed, and if it is added more than 10.0 mol%, the production cost may increase.

The organophosphorus compound used in the reaction scheme (9c) is specifically an organophosphorus compound having a high electron donating property. As an example, 2-dicyclohexylphosphino-2 ′, 6′- represented by SPhos is used. Triphenylphosphine represented by dimethoxybiphenyl or Ph ₃ P, tris (o-tolyl) phosphine represented by (o-tolyl) ₃ P, tri (t-butyl) represented by (t-Bu) ₃ P Examples include phosphine and tricyclohexylphosphine represented by Cy ₃ P. In particular, in the above reaction, it is preferable to use tris (o-tolyl) phosphine ((o-tolyl) ₃ P) from the viewpoint of polymerizability.

  The organophosphorus compound having a high electron-donating group used in the reaction scheme (9c) is presumed to coordinate with the palladium catalyst and become a ligand of the palladium catalyst. As a result, the reactivity and polymerizability are increased, the reaction proceeds easily, and a high molecular weight can be achieved. 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 amount of the organic phosphorus compound is not particularly limited as long as the Suzuki polymerization reaction proceeds, but for example, 0.5 mol% to 10.0 mol% with respect to the halogenated dithienylthienopyrazine derivative. Is preferred.

  In the reaction scheme (9c), the reaction is usually performed in the presence of a base. As the base, a general base can be appropriately selected and used. In terms of production, it is preferable to use an inorganic base such as sodium hydroxide, sodium carbonate or tripotassium phosphate or an organic base such as tetramethylammonium hydroxide, tetraethylammonium hydroxide or tetrabutylammonium hydroxide as the base. . In particular, organic bases such as tetraethylammonium hydroxide and tetrabutylammonium hydroxide are particularly preferable in terms of polymerizability because they serve as a phase transfer catalyst together with the role of the base in the reaction system. The amount of the base is not particularly limited as long as the Suzuki polymerization reaction proceeds, but it is preferably 2 equivalents or more with respect to the halogenated dithienylthienopyrazine derivative.

  As the reaction solvent in the above Suzuki polymerization, a solvent in which the halogenated dithienyl thienopyrazine derivative (4) and / or the A monomer (5) to be used is appropriately selected can be used. Specific examples of the reaction solvent include dimethylformamide (DMF) which is an amide solvent, tetrahydrofuran (THF) which is a furan solvent, toluene and xylene which are aromatic solvents, orthodichlorobenzene and chloroform which are halogen-containing solvents. These organic solvents can be used alone or in combination. Moreover, the mixed solvent of these organic solvents and water can also be used. In particular, a two-phase mixed solvent of an aromatic hydrocarbon solvent and water is preferable for dissolving a raw material monomer and a base that serves as a phase transfer catalyst. One example is a two-phase mixed solvent of toluene and water.

  The reaction temperature of the Suzuki polymerization reaction in the present invention is generally 50 ° C to 150 ° C, preferably 70 ° C to 130 ° C. If the reaction temperature is lower than 50 ° C., the reaction proceeds slowly, and if the reaction temperature is higher than 150 ° C., it may decompose and produce a low molecular weight conjugated polymer compound.

  The method for taking out the conjugated polymer compound in the present invention is not particularly limited. For example, after allowing to cool to room temperature, it is poured into a mixed solution of water and methanol and slurried, so that it can be separated from unreacted monomers, so that the obtained solid can be easily taken out by a method such as filtration. ,preferable. Although it does not specifically limit as this filtration method, For example, a Nutsche, a pressurization type filter, centrifugation, a filter press etc. can be used. Further, the obtained conjugated polymer compound may be washed with methanol and / or water. The method for removing the palladium catalyst is not particularly limited. For example, the obtained conjugated polymer compound can be removed by filtration after dissolving it in an organic solvent such as chloroform.

  The manufacturing method of the conjugated polymer compound of this invention can also include the process of drying. 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.

  Specific examples of the monomer segment of the conjugated polymer compound of the present invention are shown below. The monomer segment of the conjugated polymer compound is not limited to these. 2EtHx represents a 2-ethylhexyl group.

(Organic photoelectric conversion element)
The photoelectric conversion element using the conjugated polymer compound of 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 or 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 it is classified as a forward photoelectric conversion element or a reverse photoelectric conversion element depending on the order of stacking, as described in Japan J Applied Physics 53,05FJ08 (2014), in recent years, a non-corrosive metal such as gold is stacked on top. The reverse type photoelectric conversion element which attracts attention in terms of durability of the organic thin film solar cell device.

  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 or a transparent polymer film (polyethylene terephthalate, polycarbonate, etc.) can be suitably used as the support.

  It does not specifically limit as an electrode material of the organic photoelectric conversion element of this invention. For example, in the case of a cathode in a normal photoelectric conversion element, a cathode having a small energy barrier and a relatively small work function with respect to the LUMO level of the electron-accepting material is preferably used. Examples of such an electrode material include Al, Pt, Ir, Cr, ZnO, CNT, and alloys and composites thereof. On the other hand, in the case of the anode in the inverted photoelectric conversion element, for example, a metal having a high work function such as gold can be used.

  Since the electrode paired with the cathode of the above-described forward photoelectric conversion element or the anode of the reverse photoelectric conversion element needs to have transparency, for example, titanium oxide, zinc oxide, ITO (tin-doped indium oxide), FTO A material having transparency such as (fluorine-doped tin oxide), PEDOT: PSS (poly (3,4-ethylenedioxythiophene): poly (styrenesulfonic acid)) can be suitably 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, 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.

  Since the conjugated polymer compound of the present invention is excellent in electron donating property, it can be used as a p-type organic semiconductor material. The n-type organic semiconductor material is not particularly limited. For example, a cyano group is introduced into an oxazole derivative, a triazole derivative, a phenanthroline derivative, a phosphine oxide derivative, a fullerene compound, a carbon nanotube (CNT), or a poly-p-phenylene vinylene polymer. Derivatives (CN-PPV) and the like. 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, for example, 6,6-phenyl C ₆₁ butyric acid methyl ester (PC ₆₀ BM), 6,6-phenyl C ₇₁ -butyric acid methyl ester (PC ₇₀ BM), and the like. It is done. 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, 1,9- Suitable examples include halogenated alkanes such as diiodononane and 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.
Preferred examples of the aromatic compound include 1-chloronaphthalene and 1-bromonaphthalene.

(Organic thin film solar cell)
The organic thin film solar cell of the present invention includes the photoelectric conversion element of the present invention. Although FIG. 1 shows the forward photoelectric conversion element (A) and the reverse photoelectric conversion element (B), the present invention is not limited to this.

  Aluminum is used as a cathode electrode of a conventional forward photoelectric conversion element. This aluminum easily reacts with oxygen in the atmosphere to become insulating, and when used as a device for an organic thin film solar cell, it causes a decrease in durability and a decrease in photoelectric conversion rate. Therefore, in the present invention, a glass substrate, a transparent ITO electrode as a cathode electrode, an electron transport layer, a photoelectric conversion layer, a hole transport layer, and an anode electrode such as gold are used in order from the light receiving side. The reverse photoelectric conversion element is preferable from the viewpoint of corrosion resistance and high durability when the photoelectric conversion element of the present invention is used in an organic thin film solar cell.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, it should not be understood that the scope of the present invention is limited to these examples.

Production Example 1 Synthesis of 2,5-dibromo-3,4-dinitrothiophene
J.Chem.Crystallogr.2007,37,387 was synthesized with reference to obtain 75.5 g (yield 55.1%) of 2,5-dibromo-3,4-dinitrothiophene.
(11)

Production Example 2 Synthesis of 3 ′, 4′-dinitro-2,2 ′: 5 ′, 2 ″ -terthiophene In a 2 L separable flask, toluene / ethanol = 1/2 775 ml, 2M sodium carbonate aqueous solution 225 ml, 2,5-Dibromo-3,4-dinitrothiophene 75.0 g (0.226 mol) and 2-thiopheneboronic acid 86.7 g (0.678 mol) were added, and nitrogen was bubbled for 30 minutes. Thereafter, 26.1 g (0.023 mol, 10 mol%) of Pd (PPh ₃ ) ₄ was added, and the mixture was stirred and refluxed for 6 hours. After allowing to cool to room temperature, 2 L of water was added and extracted once with 2 L of chloroform and once with 1 L of chloroform. The organic layer was dehydrated with magnesium sulfate, filtered, concentrated with an evaporator, and dried under reduced pressure at 40 ° C. for 16 hours to obtain 98 g of a brown solid. The obtained solid was applied to a silica gel column (developing solvent: chloroform / hexane = 2/1) to fractionate a yellow fraction. This was dissolved in 300 ml of hot chloroform, reprecipitated with 300 ml of methanol, washed with 100 ml of methanol, and dried under reduced pressure at 40 ° C. for 16 hours to obtain 37.5 g (yield 49.0%) of a yellow solid.
(12)

Production Example 3 Synthesis of 3 ′, 4′-diamino-2,2 ′: 5 ′, 2 ″ -terthiophene
Chem. Mater. 1996, 8, 570 was synthesized with reference to 22.5 g of 3 ′, 4′-diamino-2,2 ′: 5 ′, 2 ″ -terthiophene (yield 74.2%).
(13)

Production Example 4 Synthesis of 5,7-bis (2-thienyl) thieno [3,4-b] pyrazine-2,3 (1H, 4H) -dione
Synthesized with reference to J. Org. Chem. 2013,78,5453-5462, and 5,7-bis (2-thienyl) thieno [3,4-b] pyrazine-2,3 (1H, 4H) -dione 16 0.6 g (yield 63.2%) was obtained.
(14)

Production Example 5 Synthesis of 5,7-bis (2-thienyl) 2,3-bis (trifluoromethanesulfonate) thieno [3,4-b] pyrazine
Synthesized with reference to J. Org. Chem. 2013, 78, 5543-5462, and 5,7-bis (2-thienyl) 2,3-bis (trifluoromethanesulfonate) thieno [3,4-b] pyrazine 23. 7 g (yield 80.3%) was obtained.
(15)

Example 1 Synthesis of Conjugated Polymer Compound 1 (Synthesis of a sulfanyl-substituted dithienylthienopyrazine derivative)
A 500 ml three-necked flask was purged with nitrogen, 200 ml of dehydrated tetrahydrofuran and 3.06 g (21.0 mmol) of octanethiol were added, and the mixture was cooled to −66 ° C. in an ethanol / dry ice bath. Thereto, 13.1 ml of normal butyl lithium hexane solution (1.6 M hexane solution, 21.0 mmol) was added dropwise and stirred for 1 hour. Then, 5.0 g (8.38 mmol) of 5,7-bis (2-thienyl) 2,3-bis (trifluoromethanesulfonate) thieno [3,4-b] pyrazine synthesized in Production Example 5/250 ml of dehydrated tetrahydrofuran Was added dropwise over 30 minutes. After removing the refrigerant and stirring for 1 hour, 400 ml of methanol was added to the reaction solution, and the precipitate was collected by filtration and washed with 300 ml of methanol. It dried under reduced pressure at 40 degreeC for 16 hours, and obtained 4.06 g (yield 82.2%) of red solid (compound A2).

(17)

About the obtained compound A2, elemental analyzer (EA: Perkin Elmer Japan Co., Ltd. 2400II fully automatic elemental analyzer) and ¹ H-nuclear magnetic resonance apparatus, ¹³ C-nuclear magnetic resonance apparatus (NMR: manufactured by JEOL Ltd.) JNM-AL300), Fourier transform infrared spectrophotometer (FT-IR: JIR-SPX60S manufactured by JEOL Ltd.), liquid chromatography mass spectrometer (LC / MS: M-8000 manufactured by Hitachi, Ltd.), gas chromatography mass The measurement results of an analyzer (GC / MS: GC / MS Spectrometer 6890N / 5973N manufactured by Agilent Technologies) and differential heat / thermogravimetry (TG / DTA: TG / DTA 6200 manufactured by SII Nano Technologies) are shown below. From these results, the structure of Compound A2 was confirmed.
Compound _{A2: C 30 H 40 N 2} S 5 molecular weight 588.98

¹ H NMR (CDCl ₃ , 300 MHz) δ (ppm): 0.88 (6H, t), 1.30 (16H, m), 1.53 (4H, m), 1.86 (4H, m), 3.38 (4H, t), 7.08 (2H, dd), 7.33 (2H, dd), 7.48 (2H, dd)
¹³ C NMR (CDCl ₃ , 75.45 MHz) δ (ppm): 14.1, 22.7, 28.7, 29.3, 29.4, 31.2, 31.8, 122.1, 123. 5, 125.8, 126.9, 134.8, 136.2, 155.3
IR (KBr) (cm ⁻¹ ): 2952, 2923, 2850, 1506, 1467, 1415, 1400, 1363, 1336, 1224, 1137, 1087, 1054, 1045, 846, 833, 821, 804, 686, 655 593
LC / MS m / z = 589.40 (APCI +)
m. p. : 99.7 ° C

(Synthesis of halogenated sulfanyl-substituted dithienyl thienopyrazine derivatives)
A DMF solution of 660 ml of DMF, 3.30 g (5.60 mmol) of Compound A2 and 2.58 g (11.5 mmol) of N-iodosuccinimide was added dropwise to a 1 L separable flask and stirred at 80 ° C. for 1 hour. Thereafter, 1 ml of a DMF solution of 0.25 g (1.12 mmol) of N-iodosuccinimide was added dropwise and stirred at 80 ° C. for 1 hour, and a solution of 0.5 ml of DMF of 0.06 g (0.28 mmol) of N-iodosuccinimide was added dropwise. And stirred at 80 ° C. for 1 hour. After cooling to room temperature, the reaction solution was poured into 300 ml of water, and the precipitate was collected by filtration and washed with 300 ml of water and 300 ml of methanol. A purple solid was obtained by drying under reduced pressure at 40 ° C. for 16 hours. The obtained solid was applied to a silica gel column (chloroform / hexane = 1/3), and a purple fraction was collected. This was purified by reprecipitation twice with chloroform and hexane and dried under reduced pressure at 40 ° C. for 16 hours to obtain 2.05 g (yield 43.5%) of a purple powder (Compound B2).

(18)

The obtained compound B2 was subjected to elemental analysis and measurement of ¹ H-NMR, ¹³ C-NMR, IR, LC / MS, and TG / DTA in the same manner as described above. The results are shown below. From these results, the structure of Compound B2 was confirmed.
Compound _{B2: C 30 H 38 I 2} N 4 S 5 molecular weight 840.77

¹ H NMR (CDCl ₃ , 300 MHz) δ (ppm): 0.88 (6H, t), 1.32 (16H, m), 1.55 (4H, m), 1.84 (4H, m), 3.28 (4H, t), 6.99 (2H, d), 7.16 (2H, d)
¹³ C NMR (CDCl ₃ , 75.45 MHz) δ (ppm): 14.1, 22.7, 28.7, 29.3, 29.7, 31.3, 31.8, 75.2, 121. 2, 123.9, 136.2, 136.3, 140.3, 155.9
IR (KBr) (cm < ^-1 >): 2954, 2923, 2852, 1506, 1494, 1463, 1405, 1365, 1303, 1139, 1062, 1047, 944, 896, 854, 779, 721, 657, 603
LC / MS m / z = 841.0 (APCI +)
m. p. 175.4 ° C

(Alkylation of carbazole derivatives)
The 2 L separable flask was replaced with nitrogen, 48.0 g of 2,7-dibromo-9-H-carbazole (148 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.), 360 ml of dimethyl sulfoxide and 41.5 g (740 mmol, 5.0 eq. ), And a solution of 91.6-heptadecane-p-toluenesulfonate 121.6 g (296 mmol, 2.0 eq.) In dimethyl sulfoxide 150 ml was added dropwise over 4 hours 30 minutes. After completion of dropping, the mixture was stirred at room temperature for 17 hours. Thereafter, 8.4 g (150 mmol, 1.0 eq.) Of powdered potassium hydroxide was added, and a solution of 36.4 g (296 mmol, 2.0 eq.) Of 9-heptadecane-p-toluenesulfonate in 40 ml of dimethyl sulfoxide was added over 25 minutes. It was dripped. After completion of dropping, the mixture was stirred at room temperature for 17 hours. The reaction solution was added to 0.6 L of water and extracted four times with 0.6 L of hexane. The organic layers were combined and washed twice with 0.6 L of water. After dehydration with magnesium sulfate, the mixture was filtered, and the solvent was distilled off under reduced pressure using an evaporator. This concentrated solution was applied to a silica gel column (developing solvent hexane), and a component having an Rf value of 0.7 was collected and concentrated by an evaporator. In an ice bath, 40 ml of hexane was added, stirred, filtered, and dried under reduced pressure at 40 ° C. for 16 hours. As a white solid, 62.6 g (yield: 75.1%) of N-9′-heptadecanyl-2,7-dibromocarbazole, which is a precursor of Compound C3, was obtained.

(19)

(Synthesis of carbazole derivatives boronated with boronic acid or its ester)
2,7-bis (4 ′, 4 ′, 5 ′, 5′-tetramethyl-1 ′, 3 ′, 2′-dioxaborolan-2′-yl) -N-9 ″ -heptadecanylcarbazole nitrogen substitution N-9′-heptadecanyl-2,7-dibromocarbazole 60.0 g (106 mmol), which is a precursor of Compound C3, and 1080 ml of tetrahydrofuran were added to the 2 L four-necked flask, and −66 in a dry ice / ethanol bath. Cooled to ° C. 266 ml (426 mmol, 4.0 eq.) Of 1.6 M butyl lithium / hexane solution was added dropwise, and the mixture was stirred at −66 ° C. for 1 hour. After stirring for 1 hour, 94.5 ml (426 mmol, 4.0 eq.) Of 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane was added, and the mixture was further stirred at 66 ° C. for 1 hour. went. It returned to room temperature and stirred at room temperature for 20 hours. Quenching was performed by adding 250 ml of methanol, and the reaction solution was concentrated with an evaporator. The precipitated solid was dispersed and washed twice with 500 ml of 50% aqueous methanol solution, and further dispersed and washed twice with 500 ml of methanol. The obtained solid was dried under reduced pressure at 50 ° C. for 16 hours. After completion of drying, reprecipitation purification with acetone / methanol was performed, followed by drying under reduced pressure at 40 ° C. for 16 hours to obtain 2,7-bis (4 ′, 4 ′, 5 ′, 5′-tetramethyl-1 as a white solid. 25.8 g (yield 37.0%) of ', 3', 2'-dioxaborolan-2'-yl) -N-9 ''-heptadecanylcarbazole (Compound C3) was obtained.

(20)

About the obtained compound C3, the elemental analysis and the measurement of ¹ H-NMR, ¹³ C-NMR, IR, LC / MS, and TG / DTA were performed in the same manner as described above. The results are shown below. From these results, the structure of Compound C3 was confirmed.
Compound C3: C ₄₁ H ₆₅ B ₂ NO ₄ molecular weight 657.58

¹ H NMR (CDCl ₃ , 300 MHz) δ (ppm): 0.81 (6H, t), 0.97 (2H, m), 1.12 (22H, m), 1.39 (24H, s), 1.93 (2H, m), 2.31 (2H, m), 4.69 (1H, m), 7.67 (2H, d), 7.89 (1H, s), 8.02 (1H , S), 8.12 (2H, t)
¹³ C NMR (CDCl ₃ , 75.45 MHz) δ (ppm): 14.1, 22.6, 24.9, 26.8, 29.2, 29.3, 29.5, 31.8, 33. 8,56.4,83.7,115.4,118.1,119.7,120.0,124.6,126.0,138.7,141.9
IR (KBr) (cm ⁻¹ ): 2981, 2923, 2856, 1621, 1558, 1481, 1454, 1430, 1349, 1267, 1145, 1079, 1054, 1033, 1014, 970, 858, 825, 690
LC / MS m / z = 657.93 (APCI +)
m. p. 144.7 ° C

(Synthesis of Conjugated Polymer Compound 1)
In a 100 ml three-necked flask, 30 ml of toluene, 15 ml of 20% tetraethylammonium hydroxide aqueous solution, 2.0 g (2.38 mmol) of compound B2, compound C3 2,7-bis (4 ′, 4 ′, 5 ′, 5′-tetramethyl) -1 ′, 3 ′, 2′-dioxaborolan-2′-yl) -N-9 ″ -heptadecanylcarbazole 1.64 g (2.5 mmol), tris (dibenzylideneacetone) dipalladium 21.8 mg (1 0.0 mol%) and 28.9 mg (4.0 mol%) of tris (o-tolyl) phosphine were added, followed by heating and stirring at 90 ° C. for 22 hours. 3 drops of iodobenzene were added and stirred for 1 hour, and 3 drops of (4 ′, 4 ′, 5 ′, 5′-tetramethyl-1 ′, 3 ′, 2′-dioxaborolan-2′-yl) benzene were added. The mixture was heated and stirred at 90 ° C. for 6 hours. The reaction solution was poured into 500 ml of 90% aqueous methanol solution, and the slurry was collected by filtration and washed with 100 ml of 90% aqueous methanol solution and 200 ml of methanol. It dried under reduced pressure at 40 degreeC for 16 hours, and obtained green solid.
The obtained solid was stirred under reflux in 1.4 L of methanol for 1 hour, and then filtered while hot. This operation was performed in the same manner in the order of acetone and hexane, and the dissolved substances in each solvent were removed. Further, 1.4 L of chloroform was stirred under reflux for 1 hour, followed by hot filtration. After repeating this operation four times, each filtrate was collected and concentrated to 50 ml with an evaporator, and 100 ml of methanol was added to form a slurry, which was collected by filtration and washed with 200 ml of methanol. It dried under reduced pressure at 40 degreeC for 16 hours, and obtained green solid (conjugated polymer compound 1: P03) 0.80g (yield 32.5%).

(21)

About the obtained conjugated polymer compound 1, the elemental analysis and IR measurement were performed similarly to the previous. The results are shown below. From these results, the monomer segment structure of the conjugated polymer compound 1 was confirmed.
Conjugated polymer compound 1
Elemental composition of the monomer _{segments: C 59 H 81 N 3 S} 5 molecular weight of the monomer segments: 992.62

IR (ATR) (cm ⁻¹ ): 2950, 2921, 2850, 1596, 1506, 1457, 1432, 1332, 1216, 1141, 1043, 997, 840, 781, 721
The obtained conjugated polymer compound 1 was measured for UV-visible spectrum. The obtained UV-visible spectrum is shown in FIG.

(Example 2) Synthesis of conjugated polymer compound 2 (synthesis of sulfanyl-substituted dithienylthienopyrazine derivative)
The 500 ml three-necked flask was purged with nitrogen, 100 ml of dehydrated tetrahydrofuran and 1.47 g (10.1 mmol) of 2-ethylhexanethiol were added, and the mixture was cooled to −66 ° C. in an ethanol / dry ice bath. Then, 6.31 ml (1.6M hexane solution, 10.1 mmol) of normal butyl lithium hexane solution was added dropwise and stirred for 1 hour. Then, 2.0 g (3.35 mmol) of 5,7-bis (2-thienyl) 2,3-bis (trifluoromethanesulfonate) thieno [3,4-b] pyrazine synthesized in Production Example 5/150 ml of dehydrated tetrahydrofuran Was added dropwise over 40 minutes. After removing the refrigerant and stirring for 1 hour, 200 ml of methanol was added to the reaction solution, and the precipitate was collected by filtration and washed with 50 ml of methanol. It dried under reduced pressure at 40 degreeC for 16 hours, and obtained red solid (compound A8) 1.70g (yield 86.3%).

For the obtained compound A8, in the same manner as in Example 1, elemental analysis and ¹ H-NMR, ¹³ C-NMR, IR, LC / MS, and TG / DTA were measured. The results are shown below. From these results, the structure of Compound A8 was confirmed.
Compound _{A8: C 30 H 40 N 2} S 5 molecular weight 588.98

¹ H NMR (CDCl ₃ , 300 MHz) δ (ppm): 0.93 (12H, m), 1.35 (8H, m), 1.53 (8H, m), 1.86 (2H, m), 3.47 (4H, m), 7.09 (2H, dd), 7.34 (2H, dd), 7.50 (2H, dd)
¹³ C NMR (CDCl ₃ , 75.45 MHz) δ (ppm): 10.8, 14.1, 23.0, 25.9, 28.8, 32.7, 35.6, 38.3, 121. 9, 123.5, 125.7, 126.9, 134.7, 136.1, 155.8
IR (KBr) (cm ⁻¹ ): 2958, 2924, 2872, 2856, 2360, 2343, 1508, 1458, 1417, 1373, 1338, 1226, 1139, 1056, 1045, 844, 833, 817, 684, 655 593
LC / MS m / z = 589.53 (APCI +)
m. p. : 73.4 ° C

(Synthesis of halogenated sulfanyl-substituted dithienyl thienopyrazine derivatives)
A 200 ml three-necked flask was charged with 50 ml of DMF and 1.0 g (1.70 mmol) of Compound A8 and heated to 50 ° C. to dissolve. N-iodosuccinimide 0.764g (3.40mmol) / DMF 20ml solution was dripped there, and it stirred at 50 degreeC for 3 hours. After allowing to cool to room temperature, 100 ml of methanol was added, and the precipitate was collected by filtration and washed with 100 ml of methanol. Drying under reduced pressure at 40 ° C. for 3 hours gave 1.32 g of a purple solid. The obtained solid was applied to a silica gel column (chloroform / hexane = 1/3), and a purple fraction was collected. This was purified by reprecipitation twice with chloroform and hexane and dried under reduced pressure at 40 ° C. for 16 hours to obtain 0.60 g (yield 42.0%) of a purple powder (Compound B8).

For the obtained compound B8, elemental analysis and ¹ H-NMR, ¹³ C-NMR, IR, LC / MS, and TG / DTA were measured in the same manner as in Example 1. The results are shown below. From these results, the structure of Compound B8 was confirmed.
Compound _{B8: C 30 H 38 I 2} N 4 S 5 molecular weight 840.77

¹ H NMR (CDCl ₃ , 300 MHz) δ (ppm): 0.95 (12H, m), 1.37 (8H, m), 1.57 (8H, m), 1.85 (2H, m), 3.40 (4H, d), 7.03 (2H, d), 7.18 (2H, d)
¹³ C NMR (CDCl ₃ , 75.45 MHz) δ (ppm): 10.7, 14.1, 233.1, 25.8, 28.6, 32.5, 36.0, 37.9, 75. 1,121.1, 124.0, 136.2, 136.4, 140.3, 156.5
IR (KBr) (cm ⁻¹ ): 2958, 2923, 2856, 1506, 1463, 1419, 1407, 1369, 1305, 1207, 1137, 1064, 1049, 943, 894, 852, 794, 784, 728, 657, 603
LC / MS m / z = 841.07 (APCI +)
m. p. 158.9 ° C

(Synthesis of Conjugated Polymer Compound 2)
Compound C3 2,7-bis synthesized in the same manner as in Example 1 in a pressure-resistant test tube reactor with 4.5 ml of toluene, 2.25 ml of 20% tetraethylammonium hydroxide aqueous solution, 0.30 g (0.36 mmol) of compound B8 (4 ′, 4 ′, 5 ′, 5 ′,-tetramethyl-1 ′, 3 ′, 2′-dioxaborolan-2′-yl) -N-9 ″ -heptadecanylcarbazole 0.246 g (0. 38 mmol), 3.3 mg (1.0 mol%) of tris (dibenzylideneacetone) dipalladium, and 4.4 mg (4.0 mol%) of tris (o-tolyl) phosphine were added, followed by heating and stirring at 90 ° C. for 22 hours. It was. Add 1 drop of iodobenzene, stir for 1 hour, 1 drop of (4 ′, 4 ′, 5 ′, 5 ′,-tetramethyl-1 ′, 3 ′, 2′-dioxaborolan-2′-yl) benzene The mixture was charged and stirred at 90 ° C. for 6 hours. The reaction solution was poured into 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. Drying under reduced pressure at 40 ° C. for 3 hours gave a green solid.
The obtained solid was stirred under reflux in 150 ml of methanol for 1 hour and then filtered while hot. This operation was performed in the same manner in the order of acetone, hexane, and toluene, and the dissolved substances in each solvent were removed. Further, the mixture was refluxed and stirred for 1 hour using 150 ml of chloroform and filtered while hot. The filtrate was concentrated to 50 ml with an evaporator, slurried with 100 ml of methanol, collected by filtration, and washed with 50 ml of methanol. It dried under reduced pressure at 40 degreeC for 16 hours, and obtained 25.7 mg (yield 7.3%) of green solid (conjugated polymer compound 2: P05).

(25)

Elemental analysis and IR measurement were performed on the obtained conjugated polymer compound 2 in the same manner as in Example 1. The results are shown below. From these results, the monomer segment structure of the conjugated polymer compound 2 was confirmed.
Conjugated polymer compound 2
Elemental composition of the monomer _{segments: C 59 H 81 N 3 S} 5 molecular weight of the monomer segments: 992.62

IR (ATR) (cm ⁻¹ ): 2954, 2921, 2852, 1596, 1506, 1457, 1432, 1332, 1214, 1137, 1041, 997, 842, 782, 721
The obtained conjugated polymer compound 2 was measured for UV-visible spectrum by the same method as in Example 1. The obtained UV-visible spectrum is shown in FIG.

Example 3 Synthesis of Conjugated Polymer Compound 3 (Synthesis of a sulfanyl-substituted dithienylthienopyrazine derivative)
The 500 ml three-necked flask was purged with nitrogen, 100 ml of dehydrated tetrahydrofuran and 0.91 g (10.1 mmol) of t-butyl mercaptan were added, and the mixture was cooled to −66 ° C. with ethanol / dry ice. Then, 6.31 ml (1.6M hexane solution, 10.1 mmol) of normal butyl lithium hexane solution was added dropwise and stirred for 1 hour. Then, 2.0 g (3.35 mmol) of 5,7-bis (2-thienyl) 2,3-bis (trifluoromethanesulfonate) thieno [3,4-b] pyrazine synthesized in Synthesis Example 5/150 ml of dehydrated tetrahydrofuran Was added dropwise over 40 minutes. After removing the refrigerant and stirring for 1 hour, 200 ml of methanol was added to the reaction solution, and the precipitate was collected by filtration and washed with 50 ml of methanol. A purple solid was obtained by drying under reduced pressure at 40 ° C. for 16 hours. The obtained solid was purified by reprecipitation with chloroform / hexane to obtain 1.15 g (yield 71.9%) of a purple solid (Compound A7).

For the obtained compound A7, elemental analysis and ¹ H-NMR, ¹³ C-NMR, IR, LC / MS, and TG / DTA were measured in the same manner as in Example 1. The results are shown below. From these results, the structure of Compound A7 was confirmed.
Compound _{A7: C 22 H 24 N 2} S 5 molecular weight 476.76

¹ H NMR (CDCl ₃ , 300 MHz) δ (ppm): 1.78 (18H, s), 7.08 (2H, dd), 7.34 (2H, dd), 7.50 (2H, dd)
¹³ C NMR (CDCl ₃ , 75.45 MHz) δ (ppm): 29.7, 50.0, 122.3, 124.0, 125.7, 127.0, 134.3, 135.2, 155. 9
IR (KBr) (cm ⁻¹ ): 2952, 2912, 2858, 1502, 1450, 1438, 1417, 1361, 1334, 1226, 1159, 1108, 1056, 1035, 846, 823, 806, 698, 682, 595
LC / MS m / z = 477.07 (APCI +)
m. p. : 242.0 ° C

(Synthesis of halogenated sulfanyl-substituted dithienyl thienopyrazine derivatives)
A 200 ml three-necked flask was charged with 50 ml of DMF and 1.0 g (2.10 mmol) of Compound A7 and heated to 50 ° C. to dissolve. N-iodosuccinimide 0.945g (4.20mmol) / DMF20ml solution was dripped there, and it stirred at 50 degreeC for 3 hours. After allowing to cool to room temperature, 100 ml of methanol was added, and the precipitate was collected by filtration and washed with 100 ml of methanol. Drying under reduced pressure at 40 ° C. for 3 hours gave 1.40 g of a purple solid. The resulting solid was purified by reprecipitation twice with toluene / methanol, then recrystallized with toluene, and dried under reduced pressure at 40 ° C. for 16 hours to give 0.66 g of purple powder (compound B7) (yield 43.1). %).

For the obtained compound B7, elemental analysis and ¹ H-NMR, ¹³ C-NMR, IR, LC / MS, and TG / DTA were measured in the same manner as in Example 1. The results are shown below. From these results, the structure of Compound B7 was confirmed.
Compound _{B7: C 22 H 22 I 2} N 2 S 5 molecular weight 728.56

¹ H NMR (CDCl ₃ , 300 MHz) δ (ppm): 1.78 (18H, s), 7.09 (2H, d), 7.19 (2H, d)
¹³ C NMR (CDCl ₃ , 75.45 MHz) δ (ppm): 29.7, 50.3, 74.5, 121.6, 124.9, 135.4, 136.7, 140.0, 156. 7
IR (KBr) (cm ⁻¹ ): 2954, 2912, 2858, 1500, 1452, 1419, 1407, 1361, 1301, 1282, 1209, 1157, 1106, 1066, 1035, 946, 900, 777, 659, 607
LC / MS m / z = 728.73 (APCI +)
m. p. : 245.3 ° C

(Synthesis of Conjugated Polymer Compound 3)
In a pressure test tube reactor, 4.5 ml of toluene, 2.25 ml of 20% tetraethylammonium hydroxide aqueous solution, 0.30 g (0.36 mmol) of compound B7, compound C3 2,7-bis (4 ′, 4 ′, synthesized in Example 1) 4 ′, 5 ′, 5 ′,-tetramethyl-1 ′, 3 ′, 2′-dioxaborolan-2′-yl) -N-9 ″ -heptadecanylcarbazole 0.246 g (0.38 mmol), tris (Dibenzylideneacetone) dipalladium 3.3 mg (1.0 mol%) and tris (o-tolyl) phosphine 4.4 mg (4.0 mol%) were added, and the mixture was heated and stirred at 90 ° C. for 22 hours. 1 drop of iodobenzene was added and 1 drop of (4 ′, 4 ′, 5 ′, 5 ′,-tetramethyl-1 ′, 3 ′, 2′-dioxaborolan-2′-yl) benzene was added for 6 hours. The mixture was heated and stirred at 90 ° C. for an hour. The reaction solution was poured into 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. Drying under reduced pressure at 40 ° C. for 3 hours gave a purple solid.
The obtained solid was stirred under reflux in 150 ml of methanol for 1 hour and then filtered while hot. This operation was performed in the same manner in the order of acetone, hexane, and toluene, and the dissolved substances in each solvent were removed. Further, the mixture was refluxed and stirred for 1 hour using 150 ml of chloroform, and filtered while hot. The filtrate was concentrated to 50 ml with an evaporator, added with 100 ml of methanol, slurried, filtered, and washed with 50 ml of methanol. It dried under reduced pressure at 40 degreeC for 16 hours, and obtained 17.6 mg (yield 4.8%) of green solid (conjugated polymer compound 3: P06).

(29)

The obtained conjugated polymer compound 3 was subjected to elemental analysis and IR measurement in the same manner as in Example 1. The results are shown below. From these results, it was confirmed that the conjugated polymer compound 3 had the monomer segment structure of the formula (29).
Conjugated polymer compound 3
Elemental composition of monomer segment: C ₅₁ H ₆₅ N ₃ S ₅ Molecular weight of monomer segment: 880.41

IR (ATR) (cm ⁻¹ ): 2952, 2921, 2852, 1596, 1498, 1457, 1430, 1361, 1338, 1216, 1157, 1108, 1033, 840, 786, 721
The obtained conjugated polymer compound 3 was measured for UV-visible spectrum by the same method as in Example 1. The obtained UV-visible spectrum is shown in FIG.

Example 4 Synthesis of Conjugated Polymer Compound 4 Compound B7 of Example 4 was synthesized in the same manner as Example 3.
In a pressure test tube reactor, 4.5 ml of toluene, 2.25 ml of 20% aqueous tetraethylammonium hydroxide, 0.30 g (0.412 mmol) of compound B7, 2,7-bis (4,4,5,5-tetramethyl- 1,3,2-dioxaborolan-2-yl) -9,9-di-n-octylfluorene (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.278 g (0.432 mmol), tris (dibenzylideneacetone) dipalladium 3.77 mg ( 1.0 mol%) and 5.02 mg (4.0 mol%) of tris (o-tolyl) phosphine were added, and the mixture was heated and stirred at 90 ° C. for 22 hours. 1 drop of iodobenzene was added and 1 drop of (4 ′, 4 ′, 5 ′, 5 ′,-tetramethyl-1 ′, 3 ′, 2′-dioxaborolan-2′-yl) benzene was added for 6 hours. The mixture was heated and stirred at 90 ° C. for an hour. The reaction solution was poured into 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. Drying under reduced pressure at 40 ° C. for 3 hours gave a green solid.
The obtained solid was stirred under reflux in 150 ml of methanol for 1 hour and then filtered while hot. This operation was performed in the same manner in the order of acetone, hexane, and toluene, and the dissolved substances in each solvent were removed. Further, the mixture was refluxed and stirred for 1 hour using 150 ml of chloroform, and filtered while hot. The filtrate was concentrated to 50 ml with an evaporator, added with 100 ml of methanol, slurried, filtered, and washed with 50 ml of methanol. It dried under reduced pressure at 40 degreeC for 16 hours, and obtained 25.6 mg (7.2% of yield) of green solid (conjugated polymer compound 4).

(31)

The obtained conjugated polymer compound 4 was subjected to elemental analysis and IR measurement in the same manner as in Example 1. The results are shown below. From these results, the monomer segment structure of the conjugated polymer compound 4 was confirmed.
Conjugated polymer compound 4
Elemental composition of monomer segment: C ₅₁ H ₆₄ N ₃ S ₅ Molecular weight of monomer segment: 865.39

IR (ATR) (cm ⁻¹ ): 2952, 2921, 2852, 1465, 1457, 1361, 1259, 1157, 1108, 1033, 881, 815, 786
The obtained conjugated polymer compound 4 was measured for UV-visible spectrum by the same method as in Example 1. The obtained UV-visible spectrum is shown in FIG.

Comparative Example 1 Synthesis of Comparative Conjugated Polymer Compound 1 (Synthesis of Sulfanylphenyl-Substituted Thienopyrazine Derivative)
Synthesis of 1,2-di (4-n-octylsulfanylphenyl) ethanedione In a 300 ml three-necked flask, 140 ml of N, N-dimethylformamide (DMF), 3.76 g (27.2 mmol, 2.0 eq.) Of potassium carbonate, dibromo Benzyl 5.0 g (13.6 mmol) and 1-octanethiol 4.17 g (28.5 mmol) were added, and the mixture was heated and stirred at 60 ° C. for 9 hours. An additional 1.88 g of potassium carbonate was added after 3 hours and 6 hours. After 9 hours of heating and stirring, the mixture was allowed to cool to room temperature, and the reaction solution, 300 ml of water and 300 ml of ethyl acetate were put into a 2 L separatory funnel. The organic layer was separated, the aqueous layer was extracted twice with 300 ml of ethyl acetate, and the organic layer was washed successively with 300 ml of saturated aqueous sodium hydrogen carbonate solution, 300 ml of water and 300 ml of saturated aqueous sodium chloride solution. After adding magnesium sulfate and dehydrating the organic layer, the added magnesium sulfate was filtered, and the organic solvent was distilled off under reduced pressure using an evaporator. 7.5 g of a yellow solid was obtained. The yellow fraction of Rf = 0.2 was fractionated by column chromatography (chloroform: hexane = 1: 1). Concentration with an evaporator gave 3.53 g (yield 52.1%) of yellow solid 1,2-di (4-n-octylsulfanylphenyl) ethanedione.

(33)

Synthesis of 2,3-di (4-n-octylsulfanylphenyl) thieno [3,4-b] pyrazine In a 500 ml three-necked flask, 300 ml of ethanol, 0.69 g (6.01 mmol) of 3,4-diaminothiophene, Synthesized 1,2-di (4-noctylsulfanylphenyl) ethanedione (3.0 g, 6.01 mmol) and acetic acid (2.0 ml, 36.1 mmol, 6.0 eq.) Were added and stirred at room temperature for 5 hours. It was. Cool in an ice bath, filter, wash with 80 ml of ethanol at 10 ° C. or lower, and dry under reduced pressure at 30 ° C. for 16 hours to obtain a light green solid 2,3-di (4-n-octylsulfanylphenyl). ) 3.31 g (yield 95.4%) of thienopyrazine was obtained.

(34)

(Synthesis of halogenated sulfanylphenyl-substituted thienopyrazine derivatives)
Synthesis of 2,3-di (4-n-octylsulfanylphenyl) -5,7-diiodothieno [3,4-b] pyrazine 2,3-di (4-n-octyl) synthesized earlier in a 300 ml three-necked flask Sulfanylphenyl) thieno [3,4-b] pyrazine (2.0 g, 3.47 mmol) and DMF (200 ml) were charged, and N-iodosuccinimide (1.95 g, 8.67 mmol, 2.5 eq.) Was charged in an ice bath. And stirred at room temperature for 21 hours. The reaction solution was poured into a mixed solution of 600 ml of toluene and 600 ml of a saturated aqueous ammonium chloride solution in an ice bath. The organic layer was separated, and the aqueous layer was extracted twice with 300 ml of toluene. The organic layers were combined and washed successively with 500 ml of saturated aqueous ammonium chloride solution and once with 500 ml of water. Dehydration with magnesium sulfate, filtration, and concentration with an evaporator gave a yellow solid. Furthermore, the yellow fraction of Rf = 0.3 was fractionated by silica gel chromatography (chloroform: hexane = 1: 1) to obtain a yellow solid. Further, reprecipitation purification was performed with chloroform and hexane, and 2.42 g (yield) of 2,3-di (4-n-octylsulfanylphenyl) -5,7-diiothieno [3,4-b] pyrazine was obtained as a yellow solid. 84.3%).

(35)

The obtained compound was subjected to elemental analysis and ¹ H-NMR, ¹³ C-NMR, IR, LC / MS, and TG / DTA measurement in the same manner as in Example 1. The results are shown below. From these results, the structure of the compound was confirmed.
2,3-di (4-n-octylsulfanylphenyl) -5,7-diiodothieno [3,4-b] pyrazine: C ₃₄ H ₄₂ I ₂ N ₂ S ₃ molecular weight 828.71

¹ H NMR (CDCl ₃ , 300 MHz) δ (ppm): 0.81 (6H, t), 0.97 (2H, m), 1.12 (22H, m), 1.39 (24H, s), 1.93 (2H, m), 2.31 (2H, m), 4.69 (1H, m), 7.67 (2H, d), 7.89 (1H, s), 8.02 (1H , S), 8.12 (2H, t)
¹³ C NMR (CDCl ₃ , 75.45 MHz) δ (ppm): 14.1, 22.6, 24.9, 26.8, 29.2, 29.3, 29.5, 31.8, 33. 8,56.4,83.7,115.4,118.1,119.7,120.0,124.6,126.0,138.7,141.9
IR (KBr) (cm ⁻¹ ): 2981, 2923, 2856, 1621, 1558, 1481, 1454, 1430, 1349, 1267, 1145, 1079, 1054, 1033, 1014, 970, 858, 825, 690
LC / MS m / z = 657.93 (APCI +)
m. p. 144.7 ° C

(Synthesis of Comparative Conjugated Polymer Compound 1)
A 50 ml three-necked flask was purged with nitrogen, 15 ml of toluene, 7.5 ml of 20% tetraethylammonium hydroxide aqueous solution, 2,3-di (4-n-octylsulfanylphenyl) -5,7-diiodhieno [3, 4-b] pyrazine 1.0 g (1.21 mmol), 2,7-bis (4 ′, 4 ′, 5 ′, 5 ′,-tetramethyl-1 ′, 3 ′, 2 ′ synthesized in Example 1 -Dioxaborolan-2′-yl) -N-9 ′ ′-heptadecanylcarbazole 0.84 g (1.27 mmol), tris (dibenzylideneacetone) dipalladium 11.1 mg (1.0 mol%), tris (o- 14.7 mg (4.0 mol%) of tolyl) phosphine was added, and the mixture was heated and stirred at 90 ° C. for 21 hours. 1 drop of iodobenzene was added and 1 drop of (4 ′, 4 ′, 5 ′, 5 ′,-tetramethyl-1 ′, 3 ′, 2′-dioxaborolan-2′-yl) benzene was added for 6 hours. The mixture was heated and stirred at 90 ° C. for an hour. The reaction solution was poured into 500 ml of 90% aqueous methanol solution, and the slurry was filtered and washed with 100 ml of 90% aqueous methanol solution and 100 ml of methanol. Drying under reduced pressure at 40 ° C. for 3 hours gave a green solid.
The obtained solid was stirred under reflux in 300 ml of methanol for 1 hour, and then filtered while hot. This operation was performed in the same manner twice with 300 ml of acetone and 300 ml of hexane, and the dissolved substances in each solvent contained in the obtained solid were removed. Further, the mixture was refluxed and stirred in 500 ml of toluene for 1 hour and filtered while hot. The filtrate was concentrated to 20 ml with an evaporator, added to 100 ml of methanol, slurried, filtered, and washed with 100 ml of methanol. It dried under reduced pressure at 50 degreeC for 16 hours, and obtained 0.60g (yield 50.4%) of comparative conjugated polymer compounds 1 as a green solid.

(36)

The obtained comparative conjugated polymer compound 1 was subjected to elemental analysis and IR measurement in the same manner as in Example 1. The results are shown below. From these results, it was confirmed that the structure of the comparative conjugated polymer compound 1 was obtained.
Comparative conjugated polymer compound 1
Elemental composition of monomer segment: C ₆₃ H ₈₅ N ₃ S ₃ Molecular weight of monomer segment: 980.56

IR (ATR) (cm ⁻¹ ): 2952, 2921, 2850, 1592, 1454, 1432, 1336, 1267, 1247, 1222, 1097, 1014, 979, 823, 796, 725, 651, 611, 538, 522
With respect to the obtained comparative conjugated polymer compound 1, the ultraviolet-visible spectrum was measured in the same manner as in Example 1. The obtained UV-visible spectrum is shown in FIG.

(Example 5)
The UV-visible spectrum and the weight average molecular weight of the conjugated polymer compounds 1 to 4 obtained in Examples 1 to 4 and the comparative conjugated polymer compound 1 obtained in Comparative Example 1 were measured, and a light resistance test was further conducted. The polymer compound obtained was evaluated.
Measurement of UV-Visible Spectral Spectrum With respect to the conjugated polymer compounds 1 to 4 and the comparative conjugated polymer compound 1, the UV-visible spectrum was measured under the following measurement conditions.
Measurement conditions of UV-visible spectroscopic curve Conjugated polymer compounds 1 to 4 and comparative conjugated polymer compound 1 were prepared using orthodichlorobenzene to prepare solutions each having a concentration of 5.0 mg / 100 ml, and UV-visible spectroscopy. Measurement was performed using a photometer (trade name: UV-1800, manufactured by Shimadzu Corporation).

  FIG. 2 shows ultraviolet-visible spectrums of the conjugated polymer compounds 1 to 4 of Examples 1 to 4 and the comparative conjugated polymer compound 1 of Comparative Example 1. Table 18 shows the results of obtaining the maximum absorption wavelength (λmax) and the molar extinction coefficient ε from the obtained spectrum.

Measurement of Weight Average Molecular Weight of Conjugated Polymer Compound The molecular weight distribution of the obtained conjugated polymer compound was measured with a Waters 515 HPLC system (manufactured by Waters, Japan) to confirm the molecular weight distribution and the weight average molecular weight.

As GPC measurement conditions, 2 mg of a sample to be measured was dissolved in 10 ml of THF, filtered through a 0.5 μm polytetrafluoroethylene (PTFE) filter to obtain a sample solution, and measurement was performed under the following conditions.
Column: Downsize column for rapid analysis Shodex KF-604 × 2
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. Table 18 shows the results of the weight average molecular weight measured under the above measurement conditions.

  In addition, the conjugated polymer compounds 1 to 4 of the present invention are polymers having an absorption band in a long wavelength region as compared to commercially available photoelectric conversion materials P3HT (up to 460 nm) and PCDTBT (up to 570 nm). High solar energy absorption efficiency can be expected.

Light Resistance Test of Conjugated Polymer Compound and Resultant Light Resistance Test Evaluation of Conjugated Polymer Compound 1-4 Obtained in Examples 1-4 and Comparative Conjugated Polymer Compound 1 Obtained in Comparative Example 1 The following procedure was followed.
Using orthodichlorobenzene for the conjugated polymer compounds 1 to 4 and the comparative conjugated polymer compound 1, solutions prepared to a concentration of 1.0 mg / 20 ml were prepared. This solution is put into a sample bottle and irradiated with light for 1 hour using a xenon light resistance tester (manufactured by Toyo Seiki Seisakusho, ATLAS SUNTEST CPS +, light source: xenon arc, irradiance 30 W / m ² (300 to 400 nm)). It was. Further, the sample solution during irradiation was attenuated by a 10% ND filter (manufactured by Nippon Vacuum Optics). The residual rate (%) was calculated from the ratio of the absorbance after irradiation when the absorbance at the maximum absorption wavelength of the sample solution before and after irradiation was measured and the absorbance before irradiation was taken as 100%. The results are shown in Table 19.

From Table 19, it was confirmed that the conjugated polymer compounds 1 to 4 of the present invention have higher light resistance than the comparative conjugated polymer compound 1. This has a thiophene structure between the thienopyrazine derivative structure and the A segment (for example, a segment derived from a carbazole derivative, a segment derived from a fluorene derivative, etc.), so that the π-conjugated system spreads two-dimensionally as a polymer. This is considered to improve the light stability and increase the light resistance.
Since the light resistance of the conjugated polymer compound of the present invention is higher than that of the comparative conjugated polymer compound 1, it is possible to prevent the conversion efficiency of the obtained photoelectric conversion element from being lowered.

(Example 6) Preparation of organic thin film solar cell element and evaluation of photoelectric conversion efficiency In Example 6, the conjugated polymer compounds 1 to 4 obtained in Examples 1 to 4 and the comparison obtained in Comparative Example 1 were used. A solar cell element using conjugated polymer compound 1 and commercially available P3HT (Comparative Example 2) as a p-type organic semiconductor was produced according to the following procedure, and the photoelectric conversion efficiency was evaluated.
Preparation of photoelectric conversion element and evaluation of photoelectric conversion efficiency An ITO glass substrate (manufactured by Geomatic, surface resistance of 10 Ω / sq or less) was subjected to ultrasonic cleaning in order with an aqueous surfactant solution, ion-exchanged water, acetone and 2-propanol. The washed ITO glass substrate was washed with ultrapure water, dried by nitrogen blowing, and then subjected to ultraviolet ozone cleaning.
(Preparation of electron transport layer)
After adding 0.11 g of zinc acetate dihydrate (manufactured by Wako Pure Chemical Industries) to 5.0 ml of ethanol and stirring at 80 ° C. for 2 hours, 30 μl of ethanolamine was added and stirred at 60 ° C. for 12 hours. The stirred solution was cooled to room temperature and then filtered through a 0.5 μm polytetrafluoroethylene (PTFE) filter. The solution was spin-coated on a cleaned substrate at 5000 rpm, and annealed at 300 ° C. for 60 minutes using a hot plate to form an electron transport layer.
(Preparation of photoelectric conversion layer)
Conjugated polymer compounds 10.0 mg described in Examples 1 to 4 and Comparative Example 1, PC ₆₀ BM (manufactured by Aldrich, purity 99.5%) 15.0 mg, 1,8-diiodooctane 6 μl (manufactured by Tokyo Chemical Industry) To 0.74 ml of orthodichlorobenzene and stirred at room temperature for 24 hours and at 80 ° C. for 2 hours. The stirred solution was cooled to room temperature and then filtered through a 0.5 μm polytetrafluoroethylene (PTFE) filter. Using this solution, the electron transport layer was spin-coated at 800 rpm and dried at room temperature for 30 minutes to form a photoelectric conversion layer.
(Preparation of hole transport layer and metal electrode)
On the photoelectric conversion layer, molybdenum oxide (manufactured by Strem Chemicals) was formed with a thickness of 10 nm as a hole transport layer, and gold was formed as an anode electrode with a thickness of 150 nm in order by vacuum deposition to prepare a solar cell element.
The IV characteristic evaluation is performed with a B2901A source / measure unit manufactured by Keysight Technologies, and the simulated solar light is a solar simulator XES-40S3-TTR manufactured by Sanei Electric Manufacturing Co., Ltd. (spectrum shape: AM1.5, intensity: 100 mW / cm ^2). ) Was used. Table 20 shows the short-circuit current density (Jsc), open-circuit voltage (Voc), fill factor (FF), and photoelectric conversion efficiency (η) obtained from the measurement.

(Comparative Example 2) Preparation and Evaluation of P3HT (Comparative Compound 2) Photoelectric Conversion Element An ITO glass substrate (manufactured by Geomatic, surface resistance of 10 Ω / sq or less) was ultrasonicated sequentially with an aqueous surfactant solution, ion-exchanged water, acetone, and ethanol. Washing was performed. The cleaned ITO glass substrate was washed with ultrapure water, dried by nitrogen blowing, and then subjected to ultraviolet ozone cleaning.
(Preparation of electron transport layer)
A titanium oxide aqueous dispersion (manufactured by Solaronics, Ti-Nanoxide HT-L / SC) was spin-coated on a substrate at 5000 rpm, and annealed at 120 ° C. for 60 minutes using a hot plate to form an electron transport layer.
(Preparation of photoelectric conversion layer and hole transport layer)
P3HT (manufactured by Aldrich, OS2100) 12.5 mg, PC ₆₀ BM (manufactured by Aldrich, purity 99.5%) 7.5 mg, 1,8-diiodooctane 11 μl (manufactured by Tokyo Kasei) are added to 0.5 ml of orthodichlorobenzene. The mixture was stirred at room temperature for 24 hours and at 65 ° C. for 2 hours. Using this solution, spin coating was performed on the electron transport layer at 850 rpm to form a photoelectric conversion layer. After drying at room temperature for 40 minutes, 1.0 wt% PEDOT: PSS aqueous dispersion (manufactured by Aldrich) was spin-coated at 2000 rpm and annealed at 140 ° C. for 5 minutes to form a hole transport layer.
(Production of metal electrodes)
On the hole transport layer, gold was formed as an anode electrode by vacuum deposition at 150 nm to produce a solar cell element.
The IV characteristic evaluation is performed with a B2901A source meter manufactured by Keysight Technologies, and the simulated solar light is a solar simulator XES-40S3-TTR (spectral shape: AM1.5, intensity: 100 mW / cm ² ) manufactured by Sanei Electric Manufacturing Co., Ltd. Using. Table 20 shows the short-circuit current density (Jsc), open-circuit voltage (Voc), fill factor (FF), and photoelectric conversion efficiency (η) obtained from the measurement.

  From Table 20, it was confirmed that the photoelectric conversion element using the conjugated polymer compound of the present invention for the p-type organic semiconductor had higher conversion efficiency than the photoelectric conversion element prepared in Comparative Example 1.

  A conjugated polymer compound containing at least the monomer segment of the sulfanyl-substituted dithienylthienopyrazine derivative of the present invention can be produced by a Suzuki polymerization reaction and can be produced with low environmental impact and high safety. A conjugated polymer compound containing at least the monomer segment of the sulfanyl-substituted dithienylthienopyrazine derivative of the present invention exhibits a low band gap and can be used as an effective organic thin-film solar cell by further forming an element.

Claims (7)

The following formula (1),
(1)
[In Formula (1), R ¹ may be the same or different, and may be a linear or branched alkyl group which may have a substituent, an aryl group which may have a substituent, or An aralkyl group which may have a substituent, A is a segment derived from a polycyclic aromatic compound composed of a carbon skeleton or a segment derived from a heterocyclic aromatic compound containing a hetero atom. ]
A conjugated polymer compound comprising a monomer segment represented by The monomer segment is represented by the following formula (2),
(2)
[In Formula (2), R ¹ is as defined above, and R ² is a linear or branched alkyl group which may have a substituent, and an aralkyl which may have a substituent. A group, an aryl group which may have a substituent, or a heteroaryl group which may have a substituent. ]
Or the following formula (3),
(3)
[In Formula (3), R ¹ is as defined above, and R ³ may be the same or different and may have a linear or branched alkyl group or substituent. An aralkyl group which may have a substituent, an aryl group which may have a substituent, or a heteroaryl group which may have a substituent. ]
The conjugated polymer compound according to claim 1, which is a monomer segment represented by the formula: A photoelectric conversion element comprising the conjugated polymer compound according to claim 1. The organic thin-film solar cell containing the photoelectric conversion element of Claim 3. Following formula (4),
(4)
[In the formula (4), R ¹ is as defined above, and X is fluorine, chlorine, bromine or iodine. ]
A halogenated thienopyrazine derivative monomer;
Following formula (5),
[In Formula (5), A is a segment derived from a polycyclic aromatic compound comprising a carbon skeleton, or a segment derived from a heterocyclic aromatic compound containing a hetero atom, and R ⁴ is boronic acid or an ester thereof. Is a residue from ]
A method for producing a conjugated polymer compound comprising subjecting a monomer represented by formula (I) to a Suzuki polymerization reaction in a reaction solvent in the presence of a palladium catalyst and an organic phosphorus compound. Following formula (6),
(6)
[In formula (6), R ¹ has the same meaning as described above. ]
A dithienylthienopyrazine derivative having a sulfanyl group represented by: Following formula (7),
(7)
[In Formula (7), R ⁵ may be the same or different and is a halogen atom, a sulfonate group, a tosyl group, a mesyl group or a nitro group. ]
A dithienylthienopyrazine derivative represented by:
Following formula (8),
[In formula (8), R ¹ has the same meaning as described above. ]
The method for producing a dithienylthienopyrazine derivative having a sulfanyl group according to claim 6, wherein the thiol compound represented by the formula is reacted in a reaction solvent in the presence of a base.