JP3837602B2 - Method for producing conductive polymer having excellent stability - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for producing a conductive polymer used for a conductive material, an electrode material, a display material, an electromagnetic wave shielding material and the like in the field of electrical and electronic industries.
[0002]
[Prior art]
Conductive polymers such as polyacetylene, polypyrrole, polythiophene, polyaniline, and polyparaphenylene are expected as new materials having various functions, and have already been put into practical use in the field of electrode materials. The functionality of a conductive polymer is based on the fact that the properties of the polymer change upon p-type doping with an oxidizing agent or n-type doping with a reducing agent, but generally the conductive polymer is p-type doped. There are many things. On the other hand, n-type doped conductive polymers have the potential to dramatically increase the field of use of conductive polymers, but their types are limited to some polymers such as polyacetylene and polyparaphenylene. . Further, conductive polymers doped with p-type can exist relatively stably in air, whereas conductive polymers doped with n-type are generally extremely unstable in air and are practically used. The development of a conductive polymer having sufficient stability has been awaited.
[0003]
[Problems to be solved by the invention]
The present invention seeks to solve the problems in the stability of conventional n-type doped conducting polymers.
[0004]
[Means for Solving the Problems]
As a result of intensive studies aimed at establishing a method for producing a conductive polymer capable of n-type doping and having excellent stability in air, the present inventors have found that atoms bonded with deprotonated hydrogen atoms. As described above, a polymer having at least one atom selected from a nitrogen atom, an oxygen atom and a sulfur atom is deprotonated with a base, and the resulting anion structure is included in a conjugated bond chain, thereby allowing n-type doping state. The inventors have found that a conductive polymer having excellent stability can be easily obtained, and have completed the present invention.
[0005]
In general, a hydrogen atom bonded to a nitrogen atom, an oxygen atom, or a sulfur atom is deprotonated in the presence of a base to generate an anion. The base cation used at this time is present in the vicinity as a counter ion. According to the present invention, “including an anion structure in a conjugated bond chain” means that an anion structure obtained by deprotonating a polymer with a base is a combination of multiple bonds and electrons previously present in the polymer. Refers to a phenomenon in which they are conjugated to each other, effectively acting as a part of the conjugated bond chain, and further giving a negative charge in the conjugated bond chain.
[0006]
Specific structural units for generating an anion structure by deprotonation in the present invention include pyrrole, indole, isoindole, naphthopyrrole, pyrrolopyridine, benzimidazole, purine, carbazole, phenoxazine, phenothiazine and the like. Examples of the ring compound structure include a hydroxyl group, a carboxylic acid group, a sulfonic acid group, a sulfinic acid group, a thiol group, and a phosphoric acid group. These structural units can generate an anionic structure by reacting with a base alone, but in order for the anionic structure to exist more stably, the structural unit must be conjugated with another adjacent multiple bond. preferable. Furthermore, the presence of an electron-withdrawing group such as a nitro group, a cyano group, an ammonium group, or a pyridinium group at a position that can affect the electron density distribution of the conjugated system is a great factor for stabilizing the anion structure. effective.
[0007]
Examples of the base used for deprotonation in the present invention include lithium, potassium, sodium, lithium hydroxide, potassium hydroxide, sodium hydroxide, lithium hydride, sodium hydride, calcium hydride, potassium t-butoxide, Sodium ethoxide, sodium methoxide, butyl lithium, phenyl lithium, lithium diisopropylamide and the like can be mentioned.
In the conductive polymer of the present invention, the cation contained in the base used in the deprotonation process becomes a counter ion of the anion structure. This cation is obtained by immersing or dissolving the polymer in another cation-containing solution. Ion exchange is possible.
The present invention will be described more specifically with reference to the following examples.
[0008]
(Example-1)
Indole (100 mg) and tetra n-butylammonium perchlorate (1.2 g) were dissolved in acetonitrile (30 ml) to prepare an electrolytic solution. Using this electrolytic solution, electropolymerization was performed by the constant potential method (1.2 V vs. silver / silver chloride electrode) using nesa glass as an anode and platinum as a cathode, and a black film-like product was obtained on the anode plate. It was.
Next, dedoping was performed in a tetra n-butylammonium perchlorate / acetonitrile solution having the same concentration as the electrolytic solution, and then the film was peeled off from the electrode and pulverized into a powder using a mortar.
Potassium t-butoxide (150 mg) was dissolved in dimethyl sulfoxide (50 ml) previously dried and distilled with molecular sieves and calcium hydride. The dedope polyindole powder was added to this base solution and stirred at 50 ° C. for 3 hours in a nitrogen atmosphere.
The polyindole powder was filtered, washed with dimethyl sulfoxide followed by acetone and vacuum dried. An elemental analysis of the product was performed by atomic absorption. As a result, 20% potassium cation was detected based on the indole monomer unit. Also, chlorine atoms were not detected at all by ordinary elemental analysis. The conductivity was measured and found to be 12 S / cm, and the value only decreased to 9 S / cm after the product was left in the air for 1 month.
[0009]
(Example-2)
A similar experiment was conducted using isoindole instead of indole used in Example 1, and the final product contained 15% potassium cation with respect to isoindole monomer units. This became clear from atomic absorption. The conductivity was measured to be 3 S / cm, and the value only decreased to 1 S / cm after the product was left in the air for 1 month.
[0010]
(Example-3)
When a similar experiment was conducted using pyrrolo [3,4-c] pyridine instead of indole used in Example-1, the final product was obtained as pyrrolo [3,4-c] pyridine. Atomic absorption revealed that it contained 23% potassium cation per monomer unit. The conductivity was measured and found to be 20 S / cm, and the value did not change even after the product was left in the air for 1 month.
[0011]
【The invention's effect】
According to the present invention, a conductive polymer having excellent stability even in an n-type doped state can be easily obtained. The conductive polymer obtained by the present invention can be used as a conductive material, an electrode material, a display material, an electromagnetic wave shielding material and the like.

Claims (1)

As atoms bonded deprotonation hydrogen atoms, and having a nitrogen atom from the "pyrrole, indole, isoindole, naphthopyrrole, pyrrolopyridine, benzimidazole, purine, carbazole, phenoxazine, and phenothiazine" A method for producing a conductive polymer having excellent stability, comprising deprotonating a polymer having a structure selected from the group consisting of a base with a base and including the obtained anionic structure in a conjugated bond chain.