JP4889085B2 - Benzodithiophene compounds - Google Patents

Description

  The present invention relates to a novel production intermediate (intermediate raw material) having a reactive functional group, and in particular, an intermediate for producing a π-conjugated polymer, and the obtained π-conjugated polymer is an organic electronics. The present invention relates to a benzodithiophene compound that is extremely useful as a raw material.

  Organic electroluminescence elements and organic transistor elements have been proposed by utilizing the light emission characteristics and charge transport characteristics of organic materials. By using an organic material for these elements, advantages such as light weight, low cost, low manufacturing cost, and flexibility are expected.

  Conventionally, various materials of low molecular weight and high molecular weight have been reported as materials for organic thin film EL elements. In low molecular weight systems, it has been reported that high efficiency is achieved by employing various laminated structures, and that durability is improved by well controlling the doping method. However, in the case of low molecular aggregates, it has been reported that the film state changes with time over a long period of time, and has an essential problem with respect to the stability of the film.

  On the other hand, in the case of polymer materials, energetic studies have been made mainly on π-conjugated polymers such as PPV (poly-p-phenylene vinylene) series and poly-thiophene.

  However, it is difficult to increase the purity of these material systems and the intrinsically low fluorescence quantum yield is cited as a problem, and at present, high-performance EL devices have not been obtained. . A polymer material containing a benzodithiophene moiety in the π-conjugated polymer main chain has also been proposed (see, for example, Patent Document 1).

  In consideration of the fact that polymer materials are inherently stable in the glass state, if high fluorescence quantum efficiency can be imparted, an excellent EL device can be constructed, and further improvements have been made in this field. .

On the other hand, various materials of low molecular weight and high molecular weight have been reported for organic thin film transistor elements. For example, pentacene, phthalocyanine, fullerene, anthradithiophene, thiophene oligomer, bisdithienothiophene and the like are used for low molecular weight materials, and polythiophene (for example, see Non-Patent Document 1) and polythienylene vinylene (for example, non-patented) for high-molecular materials. There are several materials such as reference 2).
However, even in the above materials, there is a problem regarding the stability of the film in the low molecular system, and there is a problem in the low performance due to the purity in the high molecular system, and further improvement is desired.
JP 2003-221579 A Appl. Phys. Lett. 69, 4108, 1996. Appl. Phys. Lett. 63, 1372, 1993.

  The present invention has been made in view of the above-described prior art, and is derived to various π-conjugated polymers using known reactions for producing π-conjugated polymers for organic electronics. It is an object of the present invention to provide a novel production intermediate containing a reactive functional group.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by using a production intermediate having a benzodithiophene structure having a reactive functional group for producing a π-conjugated polymer. The invention has been completed.

  In order to solve the above problems, the invention according to claim 1 provides a benzodithiophene compound represented by the following formula (I).

（上記式（Ｉ）中、Ｚは−ＰＯ（ＯＲ’）₂（式中Ｒ’は低級アルキル基を表す）を表し、Ｒ¹〜Ｒ⁸は、それぞれ独立に、水素原子、置換または無置換のアルキル基またはアルコキシ基、置換或いは無置換の芳香族炭化水素基または芳香族複素環基を表す。）

(In the above formula (I), Z represents —PO (OR ′) ₂ (wherein R ′ represents a lower alkyl group ), and R ^{1 to} R ⁸ are each independently a hydrogen atom, substituted or unsubstituted. An alkyl group or an alkoxy group, a substituted or unsubstituted aromatic hydrocarbon group or an aromatic heterocyclic group.)

  The invention described in claim 2 is a benzodithiophene compound represented by the following formula (II).

（式（ＩＩ）中、Ｙはハロゲン原子を表し、Ｒ¹〜Ｒ⁸は、それぞれ独立に、水素原子、置換または無置換のアルキル基またはアルコキシ基、置換或いは無置換の芳香族炭化水素基または芳香族複素環基を表す。）

(In Formula (II), Y represents a halogen atom, and R ^{1 to} R ⁸ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group or an alkoxy group, a substituted or unsubstituted aromatic hydrocarbon group, or Represents an aromatic heterocyclic group.)

  According to the present invention, according to the constitution of the first or second aspect of the present invention, it is possible to produce a novel arylene vinylene type benzodithiophene polymer and to modify the benzodithiophene with further functional functional groups.

Hereinafter, the compound of the present invention will be described in detail by embodiments.
First, a method for producing the benzodithiophene derivative of the present invention will be described.

(In the formula (I), Z represents —PO (OR ′) ₂ (wherein R ′ represents a lower alkyl group ), and R ^{1 to} R ⁸ are each independently a hydrogen atom, substituted or unsubstituted. Represents an alkyl group or an alkoxy group, a substituted or unsubstituted aromatic hydrocarbon group or an aromatic heterocyclic group.)
and,

（式（ＩＩ）中、Ｙはハロゲン原子を表し、Ｒ¹〜Ｒ⁸は、それぞれ独立に、水素原子、置換または無置換のアルキル基またはアルコキシ基、置換或いは無置換の芳香族炭化水素基または芳香族複素環基を表す。）

(In Formula (II), Y represents a halogen atom, and R ^{1 to} R ⁸ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group or an alkoxy group, a substituted or unsubstituted aromatic hydrocarbon group, or Represents an aromatic heterocyclic group.)

  The benzodithiophene derivative represented by the formula (II) can be easily derived from benzodithiophene. For example, after synthesizing benzodithiophene by the formula (1) according to the following method described in Journal of Organic Chemistry, 32, 3093, 1967.

  For example, the following formula (2) Vilsmeier reaction,

  Alternatively, an aryllithium compound (Ar—H) and a carbonylating agent such as DMF (dimethylformamide), N-formylmorpholine, N-formylpiperidine and the like are represented by the reaction represented by formula (3):

  Alternatively, a Gatterman reaction represented by the following formula (4):

  A dicarbonyl compound is synthesized as follows using a reaction represented by the following formula (5).

  Furthermore, this dicarbonyl compound is derived into alcohol using a reducing reagent such as sodium borohydride or lithium aluminum hydride (see formula (6)).

  Furthermore, the hydroxyl group of the alcohol is substituted with halogen by a halogenating reagent such as thionyl chloride or phosphorus bromide (see formula (7)).

  Thereby, a benzodithiophene derivative represented by the formula (II) can be obtained. Alternatively, it can also be obtained by a method of directly halomethylating benzodithiophene using paraformaldehyde and hydrogen halide or the like (see formula (8)).

  Alternatively, after synthesizing a benzodithiophene having a methyl group according to the following method described in Journal of Organic Chemistry, 32, 3093, 1967., etc. (see formula (9)),

  It can also be synthesized by radically halogenating a methyl group with a peroxide and a halogenating reagent such as N-bromosuccinimide or N-chlorosuccinimide (see formula (10)).

Next, the phosphorus compound of benzodithiophene represented by the formula (I) will be described.
The phosphorus compound of benzodithiophene represented by formula (I) can be easily derived from the halomethyl form of benzodithiophene represented by formula (II) obtained above.
For example, a reaction with a trialkylphosphonic acid ester (R in P (OR) ₃ represents a lower alkyl group) known as Michaelis-Arbuzov reaction (see formula (11))

Alternatively, from the hydroxymethyl compound, a trialkylphosphonic acid ester (in the formula: P (OR) ₃ , R represents a lower alkyl group) and an iodide are also used to represent the benzoic acid represented by the formula (I). A phosphorus compound of dithiophene can be synthesized (see formula (12)).

Among the compounds represented by the formula (I), the compound represented by Z is —P + R ″ ₃ Y— (wherein R ″ represents a phenyl group or an alkyl group, and Y represents a halogen atom). It can be easily derived from the halomethyl form of benzodithiophene represented by the formula (II). In this case, the formula (I) obtained above may be reacted with a phosphine compound (in the phosphine compound PR ₃ , R represents a phenyl group or an alkyl group), which is known as preparation of a so-called Witting reagent. (See formula (13)).

  Alternatively, it can be synthesized from the hydroxymethyl compound as in the case of a phosphonate (see formula (14)).

  By using the compound represented by the formula (I) or (II) in the present invention, a novel π-conjugated polymer useful for organic electronics can be easily obtained.

  For example, when a 2-fold mole of base is allowed to act on the compound represented by the formula (II) in a solvent, the polymerization reaction easily proceeds, and an arylene vinylene type polymer can be obtained. This is called GILCH polymerization, and details thereof are described in, for example, Macromolecules, 1999, 32, 4295-4932. (See formula (15)).

Alternatively, the polymer can be obtained by reacting the phosphorus compound represented by the formula (I) with a base in the presence of an equimolar amount of a dicarbonyl compound. This reaction is known as Wittig-Horner reaction, and an arylene vinylene type copolymer can be obtained by this method. Particularly Wittig-Horner reaction with a phosphorus compound represented by the formula (I) are highly effective from ease of reaction operation. The method for producing the polymer in the present invention using the Wittig-Horner reaction will be described in more detail.

  When a polymer is synthesized using the Wittig-Horner reaction, the phosphonic acid ester compound represented by the formula (I) and the aldehyde compound are approximately stoichiometrically equimolar as shown by the following formula. Is mixed with a base at least twice as much as the amount of the base, whereby the polymerization reaction proceeds and a polymer can be obtained (see formula (16)).

  The resulting polymer is a conjugated polymer linked by vinylene units. For this reason, the obtained polymer can obtain a very useful material as an organic electronic material excellent in light emission characteristics, charge transport characteristics and the like. Details of the production of the polymer by this reaction are described in JP-A No. 2004-18831.

Also the present invention utilizes the above Symbol W ittig-Horner reaction and the like, it is easily possible to further introduce new functional groups benzodithiophenes.

Next, the compounds represented by formulas (I) and (II) of the present invention will be described in more detail.
In the present invention, the “aromatic carbon hydrogen or aromatic heterocyclic group” may be either a monocyclic group or a polycyclic group (a condensed polycyclic group or a non-condensed polycyclic group), and examples thereof include benzene, naphthalene, biphenyl, Terphenyl, pyrene, fluorene, 9,9-dimethylfluorene, azulene, anthracene, triphenylene, chrysene, 9-benzylidenefluorene, 5H-dibenzo [a, d] cycloheptene, triphenylamine, thiophene, benzothiophene, dithienylbenzene, Examples thereof include monovalent groups or divalent groups such as furan, benzofuran, and carbazole, and these may have a substituted or unsubstituted alkyl group or alkoxy group as a substituent.

In the present specification, a substituted or unsubstituted alkyl group is a linear, branched or cyclic alkyl group having 1 to 25 carbon atoms, and these alkyl groups are further halogen atoms (particularly fluorine atoms), cyano. A phenyl group substituted with a group, a phenyl group, or a linear or branched alkyl group. Specifically, methyl group, ethyl group, n-propyl group, i-propyl group, t-butyl group, s-butyl group, n-butyl group, i-butyl group, pentyl group, hexyl group, heptyl group, Octyl, nonyl, decyl, undecyl, dodecyl, 3,7-dimethyloctyl, 2-ethylhexyl, trifluoromethyl, 2-cyanoethyl, benzyl, 4-chlorobenzyl, 4-methyl A benzyl group, a cyclopentyl group, a cyclohexyl group, etc. are mentioned.
In the case of a substituted or unsubstituted alkoxy group, specific examples include an alkoxy group formed by inserting an oxygen atom into the bonding position of the alkyl group.

  A plurality of the same substituents may be introduced, or a plurality of different groups may be introduced. In addition, these alkyl groups and alkoxy groups are further halogen atoms, cyano groups, aryl groups, hydroxyl groups, carboxyl groups, linear, branched or cyclic alkyl groups having 1 to 12 carbon atoms, alkoxy groups or alkylthio groups. An aryl group substituted with may be contained.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples.

(Synthesis of Compound 1)
Hexyl benzodithiophene (synthesized according to Journal of Organic Chemistry, 32, 3093, 1967.) 11.00 g (40.08 mmol) was placed in a 1 L four-necked flask and the system was purged with nitrogen, and then 440 ml of dry diethyl ether was added. And cooled to 0 ° C. 77 ml (120.2 mmol) of n-butyllithium 1.56Min hexane was slowly added dropwise thereto, and the mixture was stirred at room temperature for 1.5 hours after the completion of the addition. The mixture was cooled again to 0 ° C., 29.3 ml (400 mmol) of dry DMF was added, and the mixture was stirred for 0.5 hours. The reaction solution was washed with diluted hydrochloric acid and saturated brine in that order and dried over anhydrous sodium sulfate, and then the solvent was distilled off. The residue was purified by column chromatography to obtain 10.1 g (30.28 mmol) of dialdehyde (76% yield, melting point 82-83 ° C.).

  7.01 g (21.20 mmol) of dialdehyde obtained by the above operation was placed in a four-necked flask with a capacity of 500 ml, and the system was purged with nitrogen. After adding 150 ml of ethanol and 70 ml of THF, the mixture was cooled to 0 ° C., and 2.01 g (53 mmol) of sodium borohydride was added little by little. After the entire amount was added, the mixture was stirred at room temperature for 20 minutes. It was cooled again to 0 ° C. and approximately 60 ml of 1M hydrochloric acid was slowly added. Ethanol was distilled off under reduced pressure, ethyl acetate was added, and the mixture was washed with water and then saturated brine. After drying over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure to obtain 6.96 g (20.81 mmol) of the desired bishydroxymethyl compound (yield 99%, melting point 125-127 ° C.). This formula is shown in the following formula (17).

FIG. 1 shows the ¹ H NMR spectrum (400 MHz, CDCl ₃ , TMS) of the obtained bishydroxymethyl compound, and FIG. 2 shows the IR spectrum (using KBr as the window material).

(Synthesis of Compound 2)
6.95 g (20.78 mmol) of the bishydroxymethyl compound obtained in Example 1 was placed in a 200 ml four-necked flask, and the system was purged with nitrogen. After adding 30 ml of 1,4-dioxane and 4.2 ml (58.18 mmol) of thionyl chloride, the mixture was heated to 50 ° C. and stirred for 4.5 hours. After cooling to 0 ° C., a small amount of diethyl ether was added for dilution, and a saturated aqueous sodium hydrogen carbonate solution was slowly added until no foaming occurred. After extraction with diethyl ether, the organic layer was washed with saturated brine and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure to obtain 7.64 g (20.57 mmol) of the desired bischloromethyl compound (yield 99% yellow viscous liquid). This equation is shown in (18).

The ¹ H NMR spectrum (400 MHz, CDCL ₃ , TMS) of the obtained compound is shown in FIG. 3, and the IR spectrum (KBr) is shown in FIG.

  7.00 g (18.85 mmol) of the bischloromethyl product obtained in Example 2 and 14.3 ml of triethyl phosphite were placed in a 300 ml four-necked flask and heated to 135 ° C. After stirring at 135 ° C. for 5 hours, triethyl phosphite was distilled off under reduced pressure. The residue was purified by column chromatography to obtain 3.04 g (5.29 mmol) of the target phosphorus compound. (Yield 28%, yellow viscous liquid). This equation is shown in (19).

The ¹ H NMR spectrum (400 MHz, CDCl ₃ , TMS) of the obtained compound is shown in FIG. 5, and the IR spectrum (neat, NaCl) is shown in FIG.

[Polymer synthesis example]
1.522 g (2.648 mmol) of the phosphorus compound obtained in Example 3 and 0.848 g (2.648 mmol) of the dialdehyde were placed in a four-necked flask having a capacity of 200 ml, and the system was purged with nitrogen. 80 ml of dry THF and 14.05 mg (0.132 mmol) of benzaldehyde were added. To this solution, 8 ml of 1M THF solution of potassium butoxide was added dropwise, and the mixture was stirred for 2 hours after completion of the addition. Furthermore, 60.5 mg (0.265 mmol) of diethyl benzylphosphonate was added and stirred for 1 hour. The reaction solution was poured into water, and the precipitated solid was filtered to obtain 1.107 g of the polymer 1. Crude yield 71%. Further, the product was purified by reprecipitation from dichloromethane and methanol three times to obtain 0.624 g of polymer 1 as a red powder (yield 40%). This formula is shown in the following formula (20).

The elemental analysis values of the obtained polymer are shown in Table 1 below, and the IR spectrum (NaCl cast film) is shown in FIG.

  According to the present invention, a raw material for an organic polymer type semiconductor can be provided. By providing this raw material, the possibility of synthesizing a polymer in a vacuum system such as CVD or the possibility of forming a thin film by forming a film is obtained. It has become possible to provide materials that accelerate organic (semiconductor) device application research in various fields such as the element field.

1 is a ¹ H NMR spectrum of a benzodithiophene compound of the present invention (Example 1). In this figure, the horizontal axis indicates ppm, and the vertical axis indicates signal intensity (arb.). It is an infrared absorption spectrum of the benzodithiophene compound (Example 1) of this invention. In this figure, the horizontal axis represents the wave number (cm ⁻¹ ), and the horizontal axis represents the absorbance (T%). ^{1 is} a ¹ H NMR spectrum of a benzodithiophene compound of the present invention (Example 2). In this figure, the horizontal axis indicates ppm, and the vertical axis indicates signal intensity (arb.). It is an infrared absorption spectrum of the benzodithiophene compound (Example 2) of this invention. In this figure, the horizontal axis represents the wave number (cm ⁻¹ ), and the horizontal axis represents the absorbance (T%). ^{1 is} a ¹ H NMR spectrum of a benzodithiophene compound of the present invention (Example 3). In this figure, the horizontal axis indicates ppm, and the vertical axis indicates signal intensity (arb.). It is an infrared absorption spectrum of the benzodithiophene compound (Example 3) of this invention. In this figure, the horizontal axis represents the wave number (cm ⁻¹ ), and the horizontal axis represents the absorbance (T%). It is an infrared absorption spectrum of the benzodithiophene compound (application example 1) of this invention. In this figure, the horizontal axis represents the wave number (cm ⁻¹ ), and the horizontal axis represents the absorbance (T%).

Claims (2)

A benzodithiophene compound represented by the following general formula (I):

(In the formula (I), Z represents —PO (OR ′) ₂ (wherein R ′ represents a lower alkyl group ), and R ^{1 to} R ⁸ each independently represents a hydrogen atom, It represents a substituted alkyl group or alkoxy group, a substituted or unsubstituted aromatic hydrocarbon group or aromatic heterocyclic group.) A benzodithiophene compound represented by the following general formula (II):

(In the formula (II), Y represents a halogen atom, and R ^{1 to} R ⁸ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group or an alkoxy group, a substituted or unsubstituted aromatic hydrocarbon. Represents a group or an aromatic heterocyclic group.)

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