JPH0153970B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a crystalline 2,5-thienylene polymer having a 2,5-thienylene group as a repeating unit and a method for producing the same.

Conventionally, polythiophene, which has a thiophene ring as a repeating unit, has a conjugated structure similar to cis-type polyacetylene and also contains a sulfur atom, so it has been expected to have a unique electronic structure as a conductive material, and has been used in various ways. Synthetic examples have been reported.

For example, in the Journal of Polymer Science, Part A-1, Vol. Although a polymer can be obtained, it is described that this polymer has about 4 repeating units/mol and is a low polymer that is soluble in solvents such as benzene and chloroform. Also, in Journal of Chemical Society (C), Vol. 1971, p. 234, R.F.
Curteius et al. reported that several types of low polymers are obtained when thiophene is polymerized in polyphosphoric acid, but the main product is a nonconjugated compound consisting of 2,4-di-2-thienyltetrahydrothiophene. Are listed.

On the other hand, Yamamoto et al., Journal of Polymer Science Polymer Letters Edition Vol.
In the publication, 2,5-dibromothiophene is reacted with metallic magnesium in an ether solvent such as tetrahydrofuran or dibutyl ether to produce an active organomagnesium compound, and when a nickel complex catalyst is added to this, polymerization easily occurs, resulting in a polymer. It is stated that (2,5-thienylene) can be obtained. Yamamoto et al.
1079 (1981) that the polymer obtained by this method is amorphous, and that when this polymer is doped with iodine or sulfuric anhydride, its electrical conductivity increases by 7 to 9 orders of magnitude compared to the undoped polymer. ^-Four ~
It states that it becomes a semiconductor with an electrical conductivity of about 10 ^-2 S/cm.

However, the poly(2,
As mentioned above, 5-thienylene) is amorphous, and the yield of the thermal chloroform-insoluble part is low, and furthermore, according to JP-A-56-47421, the average molecular weight is 1730 (average degree of polymerization about 19) based on elemental analysis results. It is stated that the degree of polymerization is not very high.

As a result of intensive research in view of the various drawbacks mentioned above, the inventors of the present invention found that by reacting 2,5-dihalogenothiophene and metallic magnesium in an aliphatic ether solvent under an inert atmosphere, substantially active organic After removing the aliphatic ether solvent, the organic monomagnesium compound is polymerized in an aromatic ether solvent in the presence of a nickel complex catalyst under an inert atmosphere to obtain 2,5 Poly(2,5-
The present invention was accomplished by discovering that thienylene) can not only be obtained in extremely high yield and high molecular weight, but also crystalline.

It has not been previously known that the poly(2,5-thienylene) obtained in this way has crystallinity, and is truly surprising. More surprisingly, the crystalline poly(2,5-thienylene) obtained by the method of the present invention
For example, when doped with an electron acceptor such as iodine, it exhibits higher electrical conductivity than conventional materials.

In the first step, the polymer of the present invention is prepared by reacting 2,5-dihalogenothiophene and metal magnesium in an aliphatic ether solvent under an inert atmosphere to substantially form an active organomagnesium compound. After most of the group ether solvent is removed at normal pressure and/or reduced pressure, the second step is polymerization in an aromatic ether solvent under an inert atmosphere in the presence of a nickel complex catalyst. You can get it.

As the 2,5-dihalogenothiophene used in the present invention, for example, 2,5-dichlorothiophene, 2,5-dibromothiophene, 2,5-diiodothiophene or a mixture thereof is used.

Although commercially available magnesium metals are sufficient, it is desirable to use one with as high a purity as possible in order to prevent side reactions from occurring. The amount of metallic magnesium used is 0.8 per mole of dihalogenothiophene.
~1.2 mol In particular, in order to generate a monomagnesium compound and obtain a high polymer, preferably 1.2 mol is used as much as possible.
It is desirable that it be close to moles. The inert atmosphere here refers to an atmosphere in which moisture, carbon dioxide, oxygen, etc. are not present, because these react with the active organomagnesium compound and hinder the progress of the polymerization reaction.

Examples of the aliphatic ether solvent used in the first stage include diethyl ether, dibutyl ether, tetrahydrofuran, dioxane, and diethylene glycol dimethyl ether. In order to obtain a high polymer, these solvents are preferably dried. The reaction temperature can be varied over a wide range from 0°C to the boiling point of the solvent. The reaction time is 1 to 20
Although a longer time is preferably used, it is preferable to substantially convert the active organomagnesium compound into a monomagnesium form in order to obtain a high polymer, and a longer time gives better results.

The solvent used in the first stage is removed under normal pressure and/or reduced pressure. The nickel complex catalysts used in the second stage include dichloro(2,2'-bipyridine)nickel, dibromo(2,2'-bipyridine)nickel, dichlorobis(triphenylphosphine)nickel, and dibromobis(triphenylphosphine)nickel. Nickel, 1,5-cyclooctadienebis(triphenylphosphine)nickel,
Examples include nickel acetylacetonate, and the amount used is 0.05 to 10 mol%, preferably 0.1 to 5 mol%, based on 2,5-dihalogenothiophene.
It is.

Examples of aromatic ether solvents include anisole, tolyl methyl ether, diphenyl ether, and the like. As the reaction temperature, a wide range of temperatures from room temperature to 250°C can be used. The reaction time is 1
~20 hours is preferably used.

Poly(2,5-thienylene) obtained by the present invention
X is characterized by being crystalline, whereas the known poly(2,5-thienylene) is amorphous.
Linear diffraction shows a clear crystal pattern. Moreover, the average molecular weight is 3000 or more according to elemental analysis, and the degree of polymerization is high. Furthermore, the crystalline poly(2,5-thienylene) of the present invention is a known poly(2,5-thienylene).
Similarly, by doping with an electron acceptor, the conductivity increases and it becomes an excellent semiconductor, but it exhibits higher conductivity than the known poly(2,5-thienylene). As the electron acceptor, inorganic acceptors such as iodine, sulfuric anhydride, and sulfuric acid, and known organic acceptors such as tetracyanoethylene and tetracyanoquinodimethane can be used. The semiconductor thus obtained can be used in a wide variety of applications such as battery electrode materials and display material elements, and is extremely useful industrially.

The present invention will be explained below by way of examples.

Example 1 Metallic magnesium for commercially available Grignard reagents
Place 2.01 g (82.7 mmol) in a 100 ml three-necked flask equipped with a thermometer, reflux condenser, and dropping funnel.
Thoroughly purge the inside of the flask with dry nitrogen gas. Add 60ml of dry purified tetrahydrofuran to this, and while stirring with a magnetic stirrer, 20g
(82.7 mmol) of 2,5-dibromothiophene was added dropwise at room temperature. A reaction started simultaneously with the dropwise addition, and an organomagnesium compound was produced. After the dropwise addition was completed, the mixture was reacted on an oil bath at the reflux temperature of tetrahydrofuran for 9 hours. At this time, the product was decomposed with acid, extracted with ether, and analyzed by gas chromatography.
It was recognized that 2-bromothienyl-5-magnesium bromide was produced in a mol%. Thereafter, the oil bath temperature was raised to 120°C, and tetrahydrofuran was distilled off under normal pressure and then reduced pressure to obtain a reddish brown oily residue.

Add to this oily residue 60 ml of dry purified anisole and 80 mg of dichloro(2,2'-bipyridine)nickel.
(0.28 mmol) was added and reacted at 152°C for 2 hours, then poured into 500 ml of methanol acidified with hydrochloric acid and washed. After repeating this operation twice, it was filtered, and the filtration residue was Soxhlet extracted with hot methanol for 13 hours and then with hot chloroform for 50 hours, and the hot chloroform insoluble portion was 6.02 g of blackish brown fine powder.
The hot chloroform soluble portion was 0.4 g.

The elemental analysis results of this thermal chloroform insoluble part are 56.08% carbon, 2.61% hydrogen, 1.09% ash, 200ppm Ni,
Mg was 60ppm. The average molecular weight calculated as described above from the results of elemental analysis of carbon is 3880, and the average degree of polymerization is about 45. Furthermore, the results of infrared analysis (using a JASCO A-3IR spectrum photometer manufactured by JASCO Corporation) are shown in Figure 1. The absorption based on the C-Br stretching vibration near 960 cm ^-1 is extremely small, while the absorption based on the C-Br stretching vibration near 785 cm ^-1 is very small. , 5-thienylene group is extremely large, indicating that it is a high polymer. Furthermore, the X-ray diffraction diagram shown in Figure 2 (using a Rigaku Rotorflex RU-200 X-ray diffractometer) shows that 2θ = 19.8°.
Crystal peaks were present at 23.2° and 28.2°, indicating that this polymer was clearly crystalline.

The crystalline poly(2,5-
Thienylene) was compression-molded using a 1-ton press, and a slightly flexible plate-shaped molded product was obtained.
This plate-shaped molded product could be easily cut with a knife without losing its shape. This plate-shaped poly(2,5-thienylene) was exposed to iodine vapor in a glass container, doped with 65% of the polymer weight of iodine, and its electrical conductivity was measured using a 4-point conductivity meter. ²⁹⁸ = 1.58S/cm.

Example 2 The same procedure as in Example 1 was carried out, except that dry purified diethyl ether was used as the first stage solvent, and dried purified diphenyl ether was used as the second stage solvent, and polymerization was carried out at 165 ° C. for 3 hours. 6.10 g of poly(2,5-thienylene) insoluble in hot chloroform was obtained. The X-ray diffraction diagram of the polymer has a crystalline peak as in Example 1, and the electrical conductivity of a compression-molded plate obtained by a 1-ton press and doped with 60% iodine is σ ^298.
= 2S/cm.

Comparative Example 1 In the same reaction sequence as in Example 1, 12.29 g (50.8 mmol) of 2,5-dibromothiophene, 1.23 g (50.6 mmol) of metallic magnesium, and 49.2 mg (0.17 mg of dichloro(2,2'-bipyridine)nickel) were prepared. mmol), and diethylene glycol dimethyl ether was used as a dual-purpose solvent for the first and second stage reactions. First, in the first stage, the reaction was carried out at 165°C for 3 hours to completely react the metallic magnesium, and then in the second stage, a catalyst was added and the reaction was carried out at 165°C for 3 hours to obtain a dark brown polymer. This polymer had a heat chloroform soluble part of 0.66 g and a heat chloroform insoluble part of 2.16 g, so the yield of the heat chloroform insoluble part was low. The X-ray diffraction pattern of this polymer showed no peaks and was completely amorphous. Further, when the polymer was compression molded using a 1-ton press, the plate-shaped molded product obtained was brittle. Furthermore, as in Example 1, the electrical conductivity of the polymer doped with 68% iodine is σ ²⁹⁸ = 10 ^-2 S/cm
It was hot.

Comparative Example 2 Commercially available metallic magnesium for Grignard reagent
Place 3.01 g (124 mmol) in a 300 ml three-necked flask equipped with a thermometer, reflux condenser, and dropping funnel.
Thoroughly purge the inside of the flask with dry nitrogen gas. Add 90ml of dry purified tetrahydrofuran to this, and while stirring with a magnetic stirrer, 30g
(124 mmol) of 2,5-dibromothiophene was added dropwise at room temperature. The reaction starts at the same time as dropping,
An organomagnesium compound was produced. After the dropwise addition was completed, the mixture was reacted on an oil bath at the reflux temperature of tetrahydrofuran for 15.5 hours. When this product was analyzed in the same manner as in Example 1, it was found that 2-bromothienyl-5-magnesium bromide was produced at 90% or more. 120 mg (0.42 mmol) of dichloro(2,2'-bipyridyl)nickel was added to this, and the mixture was reacted for 5 hours at the reflux temperature of tetrahydrofuran, and then poured into 500 ml of methanol acidified with hydrochloric acid and washed. The obtained polymer was treated in the same manner as in Example 1 to obtain 1.96 g of a hot chloroform soluble portion and 7.68 g of a hot chloroform insoluble portion. The molecular weight of the thermal chloroform soluble portion was determined to be 940 by vapor pressure permeation method. Also, this thing's elemental analysis result is carbon 44.71
%, Hydrogen 2.94%, Mg 100ppm or less, Ni 100ppm,
The ash content was 0.65%. On the other hand, the thermal chloroform insoluble portion contained 53.11% carbon, 2.61% hydrogen, less than 100 ppm Mg, 100 ppm Ni, and 0.19% ash. The average molecular weight calculated as described above from the elemental analysis results of carbon in the thermal chloroform insoluble portion is 1740, and the average degree of polymerization is about 19. The infrared analysis result of this thing is
The ratio of the absorption considered to be based on the 2,5-thienylene group near 785 cm ^-1 and the absorption based on the C-Br stretching vibration near 960 cm ^-1 is large compared to Example 1, and the degree of polymerization is not high. It is shown that. Moreover, the X-ray diffraction diagram of this product did not show any peaks, indicating that it was completely amorphous. This comparative example shows that a crystalline polymer cannot be obtained if an aliphatic ether solvent is used in the polymerization stage.

Comparative Example 3 An attempt was made to prepare an organomagnesium compound by using anisole as a solvent on the same scale as in Example 1 and reacting at the reflux temperature of anisole for 3 hours, but no organomagnesium compound was obtained. I added a small amount of iodine as a reaction activator to this, but the results were similar. Therefore, in addition to this system, diethylene glycol dimethyl ether 30
ml was added and the reaction started. After reacting at 140°C for 2 hours, 80 mg (0.28 mmol) of dichloro(2,2'-dipyridyl)nickel was added and the mixture was heated to 140°C.
The mixture was reacted for 4 hours to obtain a polymer. The obtained polymer was treated in the same manner as in Example 1. This polymer has a methanol soluble area of 7.6% and a heat chloroform soluble area of 7.6%.
37.0%, and 55.4% of thermal chloroform insoluble portion, and the thermal chloroform insoluble portion was 0.66 g.
The X-ray diffraction diagram of this product shows no peaks,
It was completely amorphous. This comparative example shows that a crystalline polymer cannot be obtained if an aliphatic ether solvent is present during the polymerization stage.

By comparing the Examples and Comparative Examples, it is clear that the method of the present invention is superior.

[Brief explanation of drawings]

FIG. 1 is an infrared absorption spectrum diagram showing an example of the present invention, and FIG. 2 is an X-ray diffraction diagram showing an example of the present invention.

Claims (1)

[Claims] 1 General formula () A crystalline linear 2, having an average molecular weight of 3000 or more and having a 2,5-thienylene group as a repeating unit, represented by
5-thienylene polymer. 2 Under an inert atmosphere, in an aliphatic ether solvent, 2,5-dihalogenothiophene and metallic magnesium were reacted to substantially form an active organic monomagnesium compound, and the aliphatic ether solvent was removed. General formula () characterized in that the organic monomagnesium compound is then polymerized in an aromatic ether solvent in the presence of a nickel complex catalyst under an inert atmosphere. A method for producing a crystalline linear 2,5-thienylene polymer having a 2,5-thienylene group represented by the following as a repeating unit.