JPH06100669A - Conductive polymer composition - Google Patents

Abstract

PURPOSE:To obtain a solvent-sol. conductive polymer compsn. which can be formed into a film or coating film in a desired shape by doping a silole- thiophene copolymer with iodine. CONSTITUTION:The polymer is obtd. by doping, with iodine, a polymer having a backbone consisting of repeating thiophene-silole-thiophene units, e.g. a polymer of the formula wherein R is H or 1-7C hydrocarbon group; R' is a 112C org. group or a silicon group substd. by an org. group; and n is 0--20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive polymer composition, and more particularly to a novel conductive polymer composition having a thiophene-silole-thiophene skeleton.

[0002]

2. Description of the Related Art A similar phenomenon was found after it was found that polyacetylene was doped with an electron-accepting substance or an electron-donating substance to cause a charge-transfer forming reaction to develop high electrical conductivity based on electron conduction. However, since polyphenylene, polypyrrole, polyaniline, polythiophene, and the like have been found, conductive organic polymer compounds have been attracting attention in recent years. However, these polymers are poorly shaped because they are insoluble and infusible, and due to the gas phase polymerization method or electrolytic polymerization method, the shape of the produced film is limited only by the shape of the reaction vessel or electrode. Not
There was a drawback that the physical properties of the polymer were significantly deteriorated during doping.

In order to solve such a drawback, it has been proposed to introduce an alkyl group into the side chain of polythiophene, but a polymer in which silole and thiophene are combined is not known yet. Therefore, the present inventors
As a result of extensive studies to solve the above-mentioned conventional drawbacks, it is possible to obtain a stable thiophene-silole copolymer, and to express high electrical conductivity by doping the copolymer with iodine. And has reached the present invention.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a solvent-soluble conductive polymer composition which can be formed into a film or coating film having an arbitrary shape.

[0005]

The above objects of the present invention are as follows.
A conductive polymer composition obtained by doping iodine, wherein the polymer is a polymer having a thiophene-silole-thiophene skeleton as a repeating unit. . A typical example of the thiophene-silole copolymer in the present invention is represented by the general formula 2
Which is represented by the following formula:
The compound represented by can be easily obtained by reacting with a compound of nickel or palladium in the presence of a metal complex.

[0006]

[Chemical 2]

[Chemical 3] However, R in the above formula is a hydrogen atom or a monovalent hydrocarbon group having 1 to 7 carbon atoms, and R'is a monovalent organic group having 1 to 12 carbon atoms or a silicon group substituted with an organic group. And X is a halogen atom and Y is a hydrogen atom or a halogen atom. The halogen atom is most preferably a bromine atom from the viewpoint of easy handling and reactivity.

[Chemical 4] However, R and R'in the above formula are the same as those in Chemical formula 3, and M
Is SnR ₃ and M ′ is SnR ₃ or a hydrogen atom.

Examples of the tri-substituted tin group include trimethylstannyl group, tributylstannyl group and triphenylstannyl group. Examples of R include an alkyl group such as a methyl group, an ethyl group, and a propyl group, and a phenyl group, a tolyl group, a vinyl group, a 3,3,3-trifluoropropyl group, and the like. Further, as R ′, a methyl group, an ethyl group, an isopropyl group, a tertiary butyl group, a phenyl group, a benzyl group, a dihydropyranyl group, a trimethylsilyl group, a tertiary butyldimethylsilyl group, a diphenylmethylsilyl group, etc. Can be mentioned. Of these, a tertiary butyldimethylsilyl group is particularly preferable.

The compound of the above chemical formula 3 is, for example, the corresponding 2,
By treating 5-dithienylsilole with N-succinimide bromide or the like, and the compound of Chemical formula 4 is prepared by reacting 2.5-dithienylsilole with n-butyllithium, and then trialkyltin chloride or the like. Can be obtained by a known method such as adding. A metal complex of palladium or nickel is an essential catalyst for obtaining the compound of Chemical formula 2 of the present invention, and an example thereof is a general formula Cl ₂ M
(PR ¹ _{3) 2} or ^{_{Cl 2 M (R 2 2 PQPR}} 3 2) can be exemplified those represented by the other. However, M is Pd or Ni here.

As a specific example of the former, Cl ₂ Pd (PM
e ₃ ) ₂ , Cl ₂ Pd (PEt ₃ ) ₂ , Cl ₂ Pd (P
Bu ₃ ) ₂ , Cl ₂ Pd (PPh ₃ ) ₂ , Cl ₂ Pd
(P (OMe) ₃ ) ₂ , Cl ₂ Pd (P (OEt) ₃ )
₂ ; Cl ₂ Ni (PMe ₃ ) ₂ , Cl ₂ Ni (PE
t ₃ ) ₂ , Cl ₂ Ni (PBu ₃ ) ₂ , Cl ₂ Ni (P
Ph ₃ ) ₂ , Cl ₂ Ni (P (OMe) ₃ ) ₂ , Cl ₂
Ni (P (OEt) ₃ ) ₂ etc. are available;

Specific examples of the latter having a divalent ligand include Cl ₂ Pd (Ph ₂ P (CH ₂ ) ₄ PPh ₂ ), C
l ₂ Pd (Ph ₂ P (CH ₂ ) ₃ PPh ₂ ), Cl ₂ P
d (1,1-bis (diphenylphosphinoferrocene)), Cl ₂ Ni (Ph ₂ P (CH ₂ ) ₄ PP
h ₂ ), Cl ₂ Pd (Ph ₂ P (CH ₂ ) ₄ PPh ₂ )
Etc. can be mentioned.

As another example, Pd (PP
_{h 3) 4, (PhCH 2} ) PdCl (PR 1 3) 2, C
l ₂ Pd (MeCN) ₂ , Cl ₂ Pd (PhCN) ₂ ,
Cl ₂ Pd (MeCN) PR ₃ , Cl ₂ Pd (PhC
N) PR _3, include _{[Pd (π-C 3 H 3} ) Cl ] _3. However, in the above formula, Me represents a methyl group, Et represents an ethyl group, Bu represents a butyl group, and Ph represents a phenyl group.

In the present invention, the copolymer obtained as described above is doped with iodine. Doping with iodine is carried out by 1) a gas phase or dry method in which the copolymer is exposed to a vapor atmosphere of iodine, 2) iodine is dissolved in an inert solvent, and then the copolymer is added to the resulting solution. It can be carried out by a wet-doping method of immersing, and iodine is dissolved together with the copolymer in a solvent capable of dissolving the copolymer, and the resulting solution is applied and dried to perform doping simultaneously with shaping. It is also possible to adopt a simultaneous doping method that performs

In vapor phase doping, the doping rate can be controlled by controlling the temperature of the dopant atmosphere and the dopant partial pressure. In this case, the temperature is generally in the range of -30 ° C to 200 ° C. -30
If the temperature is lower than 0 ° C, the doping rate is slow, and if the temperature exceeds 200 ° C, the polymer is deteriorated during the doping, which is not preferable. The dopant partial pressure is preferably in the range of 1 mmHg to 5 atm. If it is less than 1 mmHg, the doping rate is slow, and if it exceeds 5 atm, the doping rate does not increase.

The inert solvent used for the wet doping means a solvent which does not deactivate the ability of the compound as an electron-donating compound by reacting with iodine. Such solvents include acetone, methyl ethyl ketone, ketones such as cyclohexane, hexane, octane, hydrocarbons such as cyclohexane, toluene, xylene, aromatics such as nitrobenzene, ethers, ethers such as THF, acetic acid. Esters such as ethyl, alcohols such as methanol and ethanol, aprotic polar solvents such as DMF, DMSO and HMPA, and others, nitromethane,
Acetonitrile etc. are mentioned.

Among these, a solvent such as THF dissolves the polymer very well, so that it is particularly preferable to carry out co-doping using these solvents. The drying temperature in the simultaneous doping method is usually 0 to 150 ° C., and the drying is performed under normal pressure or reduced pressure. The conductivity of the conductive polymer composition thus obtained is measured by forming four terminals on a glass plate by platinum vapor deposition to form electrodes, and then spinning the dissolved polymer solution on the electrodes. It can be easily performed by forming a thin film by coating.

As described above, the polymer having a thiophene-silole-thiophene skeleton as a repeating unit used in the present invention is soluble in a solvent and can be formed into a film or coating film having an arbitrary shape. Even if it is doped with iodine, it does not become brittle, and the conductivity is remarkably improved by 10 ⁷ to 10 ⁸ times that in the case where it is not doped with iodine.

[0017]

As described in detail above, since the conductive polymer composition of the present invention is excellent in shapeability, it is used in the fields of electricity, electronics and communication such as battery electrodes, solar cells, and electromagnetic shielding casings. Suitable for

[0018]

EXAMPLES The present invention will be described in more detail below with reference to synthesis examples and examples, but the present invention is not limited thereto. Synthesis of dithienylsilole and its dibromide

Synthesis Example 1. A 200 ml flask equipped with a cooling base, a dropping funnel, and a stirrer has the structural formula shown below.
After adding 1.45 g of 2,5-dithienylsilole represented by and 40 ml of tetrahydrofuran, 20 m of a dimethylformamide solution containing 0.85 g of N-brom succinimide.
1 was added dropwise.

[Chemical 5] 10 minutes after the addition of the dimethylformamide solution was completed, 100 ml of water was added to terminate the reaction, and hexane 100 m
It was extracted three times with 1. The organic layers were collected, washed with water and brine, and dried over sodium sulfate.

After distilling off the solvent, silica gel column chromatography (eluent: hexane / methylene chloride = 1)
0/1, Rf = 0.38) was used to obtain 1.2 g of dibromide represented by the following Chemical formula 6.

[Chemical 6] The obtained bromide was a yellow crystal having a melting point of 145 to 147 ° C. The result of elemental analysis shows that carbon atoms are 55.3.
6%, 6.02% hydrogen atoms, and C ₄₁ H ₅₂ O ₂ S ₂
In good agreement with the calculated values of 55.64% and 5.92% when Si ₃ Br ₂ was used.

Synthesis of thiophene-silole copolymer Synthesis example 2. In a dry hexane solution of 495 mg of the unsubstituted dithienylsilole (Chemical Formula 5) used in Synthesis Example 1, 0.4 ml of N, N, N ′, N′-tetramethylethylenediamine and 1.67 of n-butyllithium were added at room temperature. 1.6 ml of a molar hexane solution was sequentially added and stirred for 1 hour. Next, 0.81 ml of chlorotributyltin was added dropwise, and the mixture was further stirred for 1 hour to prepare the dibromide (Chemical Formula 6) 6 synthesized in Synthesis Example 1.
12 mg of a dry tetrahydrofuran solution of 02 mg and Cl
52 mg of ₂ Pd (PPh ₃ ) ₂ was added.

The reaction mixture was stirred at 65 ° C. for one week, the solvent was distilled off, and the rest was dissolved in 50 ml of chloroform. The chloroform solution was washed twice with a 27 mM potassium cyanide aqueous solution and twice with water, and then dried over sodium sulfate. After filtration, the solvent was distilled off, the obtained solid was dissolved in a small amount of chloroform, reprecipitated with hexane, filtered, and washed with hexane to obtain 650 mg of a dark reddish-purple polymer represented by the following chemical formula 7. It was

[Chemical 7] Weight average molecular weight 12,600, number average molecular weight 7,7
It was 00.

Example 1. The thiophene-silole copolymerization 7 produced in Synthesis Example 2 was dissolved in THF to prepare a 10 wt% solution. On the other hand, 4 terminals were formed on the glass plate by vapor deposition of platinum to form an electrode, and the solution was spin-coated on the electrode and dried at 2 mmHg / 50 ° C. to form a thin film having a thickness of 1 μm. Then, the thin film obtained under light-shielding and sealing was brought into contact with iodine and steam, and when the change in direct current resistance with time was traced, when exposed to iodine and steam,
It was confirmed that the conductivity rapidly increased and the appearance of the film changed from dark blue to black brown. The finally stable conductivity was 9.2 × 10 ⁻³ S / cm.

Example 2. The thiophene-silole copolymer obtained in Synthesis Example 2 was pressed to produce a film having a thickness of 100 μm. Then, the obtained film was sandwiched between electrodes having four terminals to prepare a sample for measuring conductivity. The obtained sample was placed in a glass bottle container connected to a vacuum line, coexisted with solid iodine, and then deaerated. After degassing, the conductivity of a sample that had been left to seal and closed with solid iodine was measured, and the conductivity of the sample exposed to iodine vapor increased rapidly, with a final drop of 1 × 10 ⁻³ S / cm. Settled in.

Comparative Example. The conductivity was measured in the same manner as in Example 2 except that solid iodine was not used at all.
It was an extremely low value of 10 ^-11 S / cm.

Claims (3)

[Claims] 1. A conductive polymer composition obtained by doping with iodine, wherein the polymer is thiophene-silole-
A conductive polymer composition, which is a polymer having a thiophene skeleton as a repeating unit. 2. The polymer represented by the following chemical formula 1.
The conductive polymer composition according to item 1; However, R in Chemical formula 1 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 7 carbon atoms, and R'is a monovalent organic group having 1 to 12 carbon atoms or a silicon group substituted with an organic group. Yes, n is 0-2
It is an integer of 0. 3. The conductive polymer composition according to claim 2, wherein R ′ in the chemical formula 1 is a tertiary butyldimethylsilyl group.