JPS63112618A - Production of n-alkyl-substituted dihydropyrrolopyrrole polymer - Google Patents

Abstract

PURPOSE:To obtain the title polymer which is formed as a film of excellent smoothness on an electrode base and is useful as an electric or electronic material, by polymerizing a specified N-alkyl-substituted dihydropyrrolopyrrole in an electrolyte solvent by electrochemical oxidation. CONSTITUTION:An electrolyte (e.g., NaClO4) is dissolved in a solvent (e.g., acetonitrile) to obtain an electrolyte solvent (B) of a concentration of 0.01mol/l to the saturation concentration. An N-alkyl-substituted dihydropyrrolopyrrole (A) of the formula (wherein R1-2 are each H or alkyl and at least either of them is alkyl) in an amount to give a concentration of 0.001mol/l to the saturation concentration in component B is polymerized by electrolytic oxidation at 0-100 deg.C and a voltage of -0.5-1.0V with respect to a saturated sodium chloride/calomel electrode, preferably, in an inert gas atmosphere by using an electrode material, e.g., Pt of an electric conductivity >=10<-3>S/cm.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing N-alkyl-substituted dihydropyrrolobyrrole polymers. This polymer is useful as an electrical/electronic material.

[Conventional technology]

It is known that a polymer can be obtained on a conductive electrode substrate by electrochemical oxidative polymerization of aromatic compounds.

For example, in the case of Virol, Journal of the Chemical Society, Chemical Communications 85
4 (1979), and for aniline in Electrochemistry Acta Vol. 1.13, 1451 (196
8) describes that a polymer is produced on the anode substrate. Conductive or semiconductive polymers have been obtained on electrodes by electrochemical oxidative polymerization of thiophene, Hensen, or their derivatives in a similar manner.

[Problem that the invention seeks to solve]

However, the polymers obtained by conventional methods adhere to the electrode substrate in the form of a film, but the film surface does not always have good smoothness, making it insufficient for applying the produced polymers to electrical and electronic materials. It was something.

[Means to solve the problem]

The present invention provides R-rich (R+ and R8 are hydrogen or alkyl groups, R+
, at least one of Rt is an alkyl group) N-alkyl ii! Provided is a method for producing an N-alkyl-substituted dihydropyrrolopyrrole polymer, which comprises electrochemically oxidatively polymerizing a substituted dihydropyrrolopyrrole in an electrolyte solvent.

As a result of intensive searches for compounds that can be electrochemically oxidatively polymerized, the present invention has revealed that N-alkyl-substituted dihydropyrrolopyrrole can be electrolytically oxidatively polymerized extremely easily, and a dense N-alkyl group with excellent smoothness can be formed on a flat electrode substrate. It was discovered that a substituted dihydropyrrolopyrrole polymer is produced in the form of a film.

The present invention will be explained in detail below.

The N-alkyl ff tA dihydropyrrolopyrrole used in the present invention is represented by the above formula, where R1 and Rt are hydrogen or an alkyl group, and at least one of R1 and R2 is an alkyl group. . Although the alkyl group is not particularly limited, specific examples thereof include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, and octyl group.

Further, these N-alkyl-substituted dihydropyrrolopyrroles are, for example, Japanese Patent Application Nos. 61-47817 and 61-509.
It can be manufactured by the method described in No. 44.

The electrolytes used in the present invention are not particularly limited as long as they are stable at the polymerization potential of N-alkyl-substituted dihydropyrrolopyrrole, but include perchlorate ions, borohalide ions, phosphorus halide ions, nitrate ions, and organic sulfone ions. Metal salts or quaternary ammonium salts containing acid ions can be used, and salts containing perchlorate ions, borohalide ions, and phosphorus halide ions are particularly preferred.

Specifically, NaClO4, (ll-Bll)4N-C1
Oi(n-Bu)mN ・PF,,(n-Bu)4N-
[IF4 etc. are exemplified.

Moreover, the solvent for the electrolyte is not particularly limited, but acetonitrile, benzonitrile, nitrobenzene, propylene carbonate, γ-butyrolactone, tetrahydrofuran, water, and the like are effectively used.

In the present invention, the concentration of N-alkyl-substituted dihydropyrrolopyrrole in the electrolyte solution should be below the saturation concentration, but if it is too low, side reactions such as decomposition of the solvent and electrolyte may easily occur during electrolytic oxidation polymerization, and electrolytic formation Usually 0.001 mol/
A concentration of 1 or more is preferred.

There are no particular restrictions on the concentration of supporting electrolyte, but is it too low? 0.01 because the resistance of electrolyte increases in agriculture.
It is used at a mole/1 or more and a saturation concentration or less.

The temperature during electrolytic oxidation polymerization is within the range where the electrolyte is in a solution state,
That is, it can be carried out at a temperature above the freezing point and below the boiling point, but usually in the range of θ°C to 100°C, preferably 10°C to 80°C.

The TL electrode material to be used is not particularly limited as long as it is stable under the electrolytic oxidative polymerization conditions and has an electrical conductivity of 10-'S/cm or more. Usually, platinum, gold, graphite l-1
Tin Mide, indium oxide-tin oxide (■To), etc. are used. These can be used alone, supported on glass or resin film, or as a composite.

Further, it is preferable that the electrolytic oxidative polymerization is performed in an atmosphere of an inert gas such as nitrogen or argon.

As the electrochemical oxidative polymerization method, commonly used methods can be used. For example, a constant current method, a constant potential method, a constant voltage method,
Although a potential sweep method, a potential step method and an alternating current method can be mentioned, a constant potential electrolysis method is preferred from the viewpoint of controlling the film thickness of the N-alkyl compatible dihydropyrrolopyrrole polymer produced.

In these reactions, the potential during polymerization is preferably -O, SV to 1.5v with respect to a saturated sodium chloride calomel electrode.

An N-alkyl-substituted dihydropyrrolopyrrole polymer can be obtained by the above method. Note that this polymer usually incorporates the anions of the electrolyte used as a supporting electrolyte, but if necessary, the electrolyte that has been incorporated can be removed by passing a current in the opposite direction to that during polymerization or by treating with an alkali. Anions can be removed.

〔Effect of the invention〕

The resulting N-alkyl-substituted dihydropyrrolopyrrole polymer is obtained in the form of a black, extremely smooth film, and when using constant potential electrolysis or constant current electrolysis, the film thickness can be controlled in proportion to the amount of electricity required for polymerization. is also a big advantage.

The film thus produced exhibits semiconductivity, but its conductivity can be further increased by further chemical doping, electrochemical doping, or ion implantation.

Furthermore, this polymer membrane can be electrochemically reduced (undoped) in an electrolyte (organic solvent or aqueous solvent) and easily turns yellowish brown, so it can be used as an electrochromic device. Other application examples include sensors and electronic devices using modified electrodes, and they have great industrial value as electrical and electronic materials.

〔Example〕

The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited to these.

Example I 10 mmol/1 N,N'-dimethyldihydropyrrolopyrrole as 7-mer, 0.1 n as supporting salt
The electrolyte was an acetonitrile solution containing ot/f sodium perchlorate. The working electrode was a flat plate of pyrolytic graphite (hereinafter referred to as BPG), the counter electrode was a platinum plate, and the reference electrode was a saturated sodium chloride calomel electrode ( (hereinafter abbreviated as SSCε) was used.

After bubbling nitrogen gas into the electrolyte for 30 minutes, the potential was swept from 10,6 V to 0.6 V at a sweep rate of 50 wV/sec for 5SCH under a nitrogen gas flow, and
Electrolytic oxidation polymerization was performed at ℃ for 10 minutes, and a 0.
A black N,N'-dimethyldihydropyrrolopyrrole polymer of 4 μm was obtained. When observed with a scanning electron microscope, the film surface was extremely smooth and no disturbances were observed.

When the solubility of this polymer film was investigated, it was found that 2,4.6-trimethylpyridine, dimethyl sulfoxide, N, N'-
Dimethylformamide, methanol, ethanol, tetrahydrofuran, propylene carbonate, acetone,
Nitrobenzene, 1,2-dichloroethane, hexane,
Hexamethylphosphoric acid triamide 5: Insoluble in concentrated sulfuric acid, trifluoroacetic acid, and fuming nitric acid.

Example 2 N, N obtained on the BPG surface by the same method as Example 1
'-dimethyldihydropyrrolopyrrole polymer for 0°1s
ol/j! Acetonitrile containing sodium perchlorate or tetrabutylammonium perchlorate m? 5SCI with a platinum plate as the opposite electrode in a! For, -0,8V to 0
．． The potential was swept between 2V at a sweep rate of 200mV.

As a result, a clear redox response was observed for each electrolyte, and the amount of electricity for the oxidation reaction and the amount of electricity for the reduction reaction were within the experimental error, and the doping and dedoping of perchlorate ions were reversible. showed what happens.

This polymer film was black in the oxidized state and yellowish brown in the reduced state.

Example 3 N was prepared in the same manner as in Example 1 except that the working electrode was a platinum plate.
, N'-dimethyldihydropyrrolopyrrole polymer was obtained. When observed with a scanning electron microscope, the surface of the obtained polymer film was extremely smooth.

Example 4 An ITO film was used as the working electrode, and the potential (I
A 'J,N'-dimethyldihydropyrrolobyrol polymer was obtained on the rTO film in the same manner as in Example 1 except that the voltage was between -0.6v and 0.9v with respect to C. When observed with a scanning electron microscope, the surface of the obtained polymer film was smooth and smooth.

Example 5 The same electrolyte as in Example 1 was used, and the working rod was an ITO membrane,
The counter electrode was a platinum plate and the reference electrode was 5SCE.
Electrolytic oxidation polymerization was carried out at a constant potential of 0.9v with respect to SCH,
When the relationship between the amount of electricity applied and the film thickness of the N,N'-dimethyldihydropyrrolopyrrole polymer was determined, the film thickness of the polymer was 0.2 μm, growing at a rate of 150 mC-Cm-'', It was shown that the film thickness can be controlled by changing the amount.

Example 6 An ITO film was obtained in the same manner as in Example 4. An N,N"-dimethyldihydropyrrolopyrrol polymer film with a thickness of 2.4 μm was obtained. The electrical conductivity of this polymer was l x 10 -'S/
It was cm.

Example 7 The same procedure as in Example 4 was carried out except that the supporting salt was LiBF, and an N,N'-dimethyldihydropyrrolobyroll polymer film was obtained on tTOlli. When observed with a scanning electron microscope, the surface of the obtained polymer film was extremely smooth. Example 8 The same procedure as Example 4 was performed except that propylene carbonate was used as the solvent. A dimethyl dihydropyrrolopyrrole polymer membrane was obtained. When observed with a scanning electron microscope, the surface of the obtained polymer film was extremely smooth.

Example 9 10 mmol/! as monomer! l of N,N'-diethyldihydropyrrolopyrrole, 0.1 m as supporting salt
BPG was used as the working electrode, a platinum plate was used as the counter electrode, and 5SCE was used as the reference electrode, using an acetonitrile solution containing ol/12 sodium perchlorate as the electrolyte.

After bubbling nitrogen gas into the above electrolyte for 30 minutes, constant potential electrolytic oxidation polymerization was performed on 5SCH at 0.9ν under a nitrogen gas stream, and a black N,N'-diethyldihydropyrrolobyroll polymer was formed on BPG. The coalescence formed into a film. When observed with a scanning electron microscope, the surface of the obtained polymer film was extremely smooth.

Example 10 Black N,N'-di-tert-butyldihydropyrrolopyrrole polymer was deposited on BPG in the same manner as in Example 9 except that N,N'-di↑ert-butyldihydropyrrolobyrrole was used as the monomer. A membrane was obtained. When observed with a scanning electron microscope, the surface of the obtained polymer film was extremely smooth.

Claims (1)

[Claims] Formula ▲ Numerical formula, chemical formula, table, etc. ▼ (R_1 and R_2 are hydrogen or an alkyl group, and at least one of R_1 and R_2 is an alkyl group)
A method for producing an N-alkyl-substituted dihydropyrrolopyrrole polymer, which comprises electrochemically oxidatively polymerizing the N-alkyl-substituted dihydropyrrolopyrrole represented by