JPH0331364A - Production of electrically conductive polysilane - Google Patents

Abstract

PURPOSE:To produce a polysilane having high electrical conductivity by treating a polysilane having a hetero-ring on silicon atom as a substituent with an organic carboxylic acid. CONSTITUTION:A polysilane containing a structural unit of formula I (R<1> and R<2> are alkyl, aryl or aralkyl; R<3> is H, alkyl, aryl or aralkyl) and optionally further containing a structural unit of formula II (R<4> and R<5> are alkyl, aryl or aralkyl) is treated with a dopant of formula III [R<6> is H, alkyl or halogen- substituted alkyl) (e.g. trifluoroacetic acid or benzoic acid). The above polysilane can be produced by reacting an alkali metal to a bifunctional silicon compound of formula IV (X is halogen) or to the compound of formula IV and a dihalosilane of formula V.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing conductive polysilane, and more specifically, the present invention relates to a method for producing conductive polysilane, and more specifically, a conductive polysilane is produced by treating polysilane having an indolyl-substituted silane structural unit with an organic carboxylic acid. Regarding how to get .

Conventionally, metals have been used exclusively as materials that require electrical conductivity, and organic polymer compounds have generally been treated as insulating materials.

However, in recent years, it has been discovered that polysilane exhibits electrical conductivity when brought into contact with a strong electron acceptor such as arsenic pentafluoride, and is attracting attention as a new electrically conductive material.

For example, by irradiating polymethylphenylsilane with light to give it a crosslinked structure, and allowing arsenic pentafluoride to act as a dopant, it is possible to obtain polysilane with high electrical conductivity on the order of O, SS/am. It has been found (J, Amer.

Chell, Soc, 103.7352-735
4 (1981)). However, with such conductive polysilane, it is difficult to obtain reproducibility in the formation of a crosslinked structure of polysilane by light irradiation, and the toxicity of the dopant also makes it difficult to put it into practice.

Therefore, Japanese Patent Application Laid-Open No. 62-059632 discloses that after dissolving polydimethylsilane or polymethylphenylsilane in 4-sulfuric acid, this solution is heated to remove the sulfuric acid by evaporation.
A method of obtaining conductive polysilane has been proposed. According to this method, it is said that polysilane having a conductivity of about 10-S to IO3/cm can be obtained.

On the other hand, various polysilanes have been known so far, but most of them are polysilanes that have a hydrocarbon group such as an alkyl group or a phenyl group on a silicon atom, and polysilanes that have a heterocycle as a substituent on a silicon atom. is almost unknown.

In order to solve the above-mentioned problems in the production of conventional conductive polysilane, the present inventors have conducted extensive research and have developed a new method that has a heterocycle as a substituent on a silicon atom. The present invention was achieved based on the discovery that a highly conductive polysilane can be easily obtained by obtaining a polysilane and treating the polysilane with an organic carboxylic acid.

The method for manufacturing conductive polysilane according to the present invention for improving the function is expressed by the general formula (
Ia) (Ia) (wherein R1 and H2 are each independently an alkyl group,
The aryl group or aralkyl group, R3, represents hydrogen, an alkyl group, an aralkyl group, or an aralkyl group. ) is treated with a dopant represented by the general formula % (II) (wherein R6 represents hydrogen, an alkyl group, or a halogen-substituted alkyl group). do.

In the present invention, the polysilane used is of the general formula (
It may be a homopolymer consisting only of the structural unit represented by Ia), or it may be a copolymer containing the structural unit represented by the general formula (Ia). In the case of such a copolymer, the structural unit represented by the general formula (Ia) is preferably contained in an amount of at least 1 mol % in the polymer chain.

As a copolymer containing a structural unit represented by the general formula (Ia), a structural unit represented by the general formula (Ia) and a general formula (rb) (Ib) (wherein R4 and R5 are each independently an alkyl group,
Indicates an aryl group or an aralkyl group. ) is preferably used.

In the structural unit represented by the above general formula (I a),
R1 preferably represents an alkyl group having 1 to 10 carbon atoms, an aralkyl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms, and specific examples of the alkyl group include:
For example, methyl, ethyl, n-propyl, isopropyl, n-butyl, 5ec-butyl, t-butyl, amyl,
Hexyl, octyl, dodecyl groups, etc.; examples of tolyl groups include phenyl, tolyl, methoxyphenyl groups, etc.; examples of aralkyl groups include benzyl, phenethyl, p-methylbenzyl groups, etc. be able to.

In the above general formula (I a), R2 is preferably:
Indicates an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms. Specific examples of the alkyl group include methyl, ethyl, n-propyl, and isopropyl. , n-butyl, 5ec-
Butyl, t-butyl, amyl, hexyl groups, etc., aryl groups include phenyl, tolyl, methoxyphenyl groups, etc., and aralkyl groups include, for example,
Mention may be made of benzyl, phenethyl and p-methylbenzyl radical rings.

In the above general formula C1a), R3 represents hydrogen, or preferably an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms as described above, particularly , preferably hydrogen.

On the other hand, in the structural unit represented by the above general formula (Ib), R4 and R5 preferably each independently,
It represents an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms. Specific examples of the alkyl group include methyl, ethyl, n-propyl, and isopropyl. , n-butyl, 5ec
-butyl, t-butyl, amyl, hexyl, octyl,
Examples of the aryl group include phenyl, tolyl, and methoxyphenyl, and examples of the aralkyl group include benzyl, phenethyl, p-methylbenzyl, and the like.

The homopolymer consisting of the structural unit represented by the general formula (Ia) used in the present invention has the formula -a () (1) (wherein R1, Ht and R3 are the same as above, and X is a halogen It can be obtained by reacting a bifunctional silicon compound represented by (indicates an atom) with an alkali metal.

Similarly, a copolymer consisting of the structural unit represented by the above-mentioned (Ia) and the structural unit represented by the above-mentioned general formula (Ib) can be obtained by combining a bifunctional silicon compound represented by the above-mentioned general formula (I[[) and a general Formula (IV)
It represents an aryl group or an aralkyl group, and X is the same as above. ) can be obtained by reacting a dihalosilane represented by the following with an alkali metal.

In the bifunctional silicon compound represented by the general formula (III), R1, Rg, and R3 are the same as above, and X
is preferably chlorine, bromine or iodine, particularly preferably chlorine.

Therefore, specific examples of the bifunctional silicon compound represented by the above general formula (III) include dichloromethyl(2-(1-methylindolyl))silane, dichlorophenyl(2-(1-methylindolyl)) ] Silane, etc. Such a bifunctional silicon compound is a new compound, and can be obtained by the method described below.In addition, in the dihalosilane represented by the general formula (TV), R4 and BS is the same as above, and X is
Chlorine, bromine or iodine is preferred, and chlorine is particularly preferred.

Therefore, as such dihalosilane, for example, dimethyldichlorosilane, diphenyldichlorosilane, dichloromethylphenylsilane, etc. are preferably used.

Examples of the alkali metals include sodium metal, lithium metal, potassium metal, and the like. These alkali metals may be used alone or in combination of two or more. However, in the present invention, it is particularly preferable to use metallic sodium.

When reacting the bifunctional silicon compound and, if necessary, the dihalosilane with an alkali metal, the total amount of the bifunctional silicon compound and dihalosilane is usually 1.8 to 5 % based on the alkali metal. It is used in an amount of .0 times the molar amount, preferably in a range of 2.0 to 2.5 times the molar amount. The alkali metal is usually used in the form of a dispersion by dispersing it in a solvent that is inert to the alkali metal.

The reaction of the difunctional silicon compound and, if necessary, the dihalosilane with the alkali metal is usually carried out in a liquid phase using a solvent. The solvent used has no reactivity with alkali metals and is inert, as well as the raw material 2.
It is also a solvent that is inert towards functional silicon compounds and dihalosilanes. Specific examples of such solvents include aromatic hydrocarbon solvents, saturated hydrocarbon solvents, unsaturated hydrocarbon solvents, and ether solvents. In particular, saturated hydrocarbon solvents such as dodecane and decane, aromatic hydrocarbon solvents such as toluene, benzene and xylene, and ether solvents such as tetrahydrofuran are preferably used. These solvents may be used alone or as a mixture of two or more.

The reaction is usually carried out at a temperature ranging from -50°C to 300°C. Preferably, the reaction temperature is appropriately selected depending on the solvent used, for example, when using a saturated hydrocarbon solvent, it is usually 120 to 200°C, and when using an aromatic hydrocarbon solvent, it is 80 to 200°C. ℃, and when using an ether solvent, the temperature is preferably in the range of 20 to 150℃.

Furthermore, the reaction can be carried out both under reduced pressure and under increased pressure.
The reaction pressure is, but not limited to, from reduced pressure to 60
kg/-. However, usually 0-30k
g/cd, preferably in the range of 0 to 5 kg/-.

The reaction time is appropriately set in consideration of reaction temperature, pressure, etc., but is usually 5 minutes to 1 week, preferably 5 to 80 hours.

Furthermore, such reactions are usually conducted under an inert atmosphere. As the inert atmosphere, for example, argon or nitrogen atmosphere is used.

The bifunctional silicon compound represented by the general formula (III) is prepared under an inert atmosphere by converting the N- The substituted indole is reacted with alkyllithium, aryllithium or aralkyllithium, and then the general formula (Vl) R'-5i-X (Vl) (wherein 1) 71 and X are the same as above. ) can be obtained by reacting a trihalosilane represented by:

In the N-substituted indole represented by the above general formula (V), R2 and R3 are the same as above, and therefore, preferred examples of the N-substituted indole include N-methylindole and N-phenylindole. This can be cited as an example.

In addition, examples of the alkyllithium include methyllithium, ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, 5ec-butyllithium, t-butyllithium, amyllithium,
Examples include hexyllithium. Examples of tolyllithium include phenyllithium, tolyllithium, methoxyphenyllithium, and the like.

Furthermore, examples of the aralkyllithium include benzyllithium, phenethyllithium, p-methylbenzyllithium, and the like. Among such organolithiums, t-butyllithium is particularly preferably used.

The above reaction is carried out under an inert atmosphere, usually in a solvent. The solvent is not particularly limited as long as it is inert to the organolithium compounds mentioned above, but examples include ether solvents such as diethyl ether, dimethoxyethane, dioxane, and tetrahydrofuran, pentane, and hexane. Aromatic hydrocarbons such as benzene, toluene, xylene, etc., or mixed solvents thereof are preferably used. Moreover, the organolithium is also usually prepared in the same inert solvent as these and used as such a solution. Generally, nitrogen, argon, etc. are suitable as the inert atmosphere.

By reacting the N-substituted indole with an organic lithium as described above, a lithiated N represented by the general formula (■)t (■) (wherein R2 and R'3 are the same as above) is produced. A substituted indole compound is obtained. However, usually, without isolating such a lithiated N-substituted indole compound, the above-mentioned indolyl-substituted bifunctional organic Silicon compounds can be obtained.

As the trihalosilane represented by the general formula (VI), for example, methyltrichlorosilane, phenyltrichlorosilane, etc. are preferably used.

In the reaction between the N-substituted indole and the organolithium, the organolithium is usually used in an amount of 1 to 1.2 mol per 1 mol of the N-substituted indole. Also,
Trihalosilane is also generally used in an amount of 1.0 to 1.2 mol per 1 mol of N-substituted indole.

The reaction temperature, reaction time, etc. are not particularly limited, but for example, in the reaction of N-substituted indole and organolithium, the organic lithium solution is added to the N-substituted indole solution, usually at -100°C to 25°C. , preferably -8
After adding at a temperature in the range of 0℃ to -30℃, -30℃
to 80° C., preferably 0 to 40° C., and is stirred typically for several minutes to about 10 hours, preferably for 30 minutes to 2 hours, thus forming the lithiated N-substituted indole.

Then, in the reaction of this lithiated N-substituted indole with a trihalosilane, the lithiated N-substituted indole is added to the reaction mixture containing the trihalosilane, usually at -100
After addition at a temperature in the range of -80°C to 30°C, it is added at a temperature in the range of -30°C to 80°C, preferably 0 to 50°C, usually for 30 minutes to The reaction is allowed to proceed for about 40 hours, preferably from 1 hour to 20 hours, with stirring.

After the reaction is completed, the solvent is distilled off from the reaction mixture under reduced pressure, and the resulting residue is recrystallized from an appropriate solvent or distilled under reduced pressure to obtain the desired indolyl-substituted bifunctional organosilicon compound. can.

As the recrystallization solvent, aromatic hydrocarbons, aliphatic hydrocarbons, or mixed solvents thereof are suitable, for example.

In such a method, corresponding to the N-substituted indoles and trihalosilanes, for example, dichloromethyl (
2-(1-methylindolyl)]silane, dichlorophenyl(2-(1-methylindolyl))silane, etc. can be obtained.

By using such indolyl-substituted silane compounds, polymethyl(2-(1-methylindolyl))silane, polyphenyl[2-(1-methylindolyl)]silane, polymethyl(2-(1-methylindolyl)) phenylindolyl)] silane, etc., polymethyl (2
-(1-methylindolyl)]silane/methylphenylsilane copolymer and the like can be obtained.

Polysilanes obtained in this way usually have a conductivity of σ
is less than or equal to IQ-'S/cm. According to the present invention, such a polysilane is treated with a dopant represented by the general formula (II) R''-COOH (n) (wherein R6 represents hydrogen, an alkyl group, or a halogen-substituted alkyl group). Highly conductive polysilane can be easily obtained.

Specific examples of the organic carboxylic acid used as the dopant represented by the general formula (II) include aliphatic carboxylic acids having 1 to 6 carbon atoms such as formic acid, acetic acid, propionic acid, and butyric acid, trichloroacetic acid, and trifluoroacetic acid. Trihaloacetic acids such as acetic acid, benzoic acid, halogenated benzoic acids such as p-chlorobenzoic acid, p-fluorobenzoic acid, alkyl-substituted benzoic acids such as p-methylbenzoic acid, trichloromethylbenzoic acid, trifluoromethylbenzoic acid, etc. Trihalomethylbenzoic acid and the like can be mentioned.

These dopants can be used alone or in combination of two or more.

In the present invention, the method of adding a dopant to polysilane as described above is not particularly limited.
For example, a method in which polysilane is dissolved in the dopant itself or a solution of the dopant and then the dopant and solvent are removed by evaporation, a method in which a film made of polysilane is formed and a dopant is applied to this film, a method in which a film made in polysilane is formed,
A method of contacting this film with a dopant in the form of vapor can be used.

According to the present invention, by adding an organic carboxylic acid as a dopant to polysilane as described above,
High conductivity can be imparted.

The conductive polysilane obtained usually has a 10-4 to 10-
' with conductivity in the range of S/am.

According to the present invention, the base material is a polysilane containing a structural unit having a 5i-3i bond in the main chain and having an indolyl group containing a basic nitrogen atom as a direct substituent on a silicon atom. Used as polymers, such polysilanes are easily doped with organic carboxylic acids to provide highly conductive polysilanes.

Examples of the synthesis of indolyl-substituted bifunctional silane compounds and polysilanes using the same will be described below as reference examples, and the present invention will be explained with reference to examples, but the present invention is not limited by these examples in any way. It's not a thing.

Reference Example 1 (Synthesis of dichloromethyl(2-(]-methylindolyl))silane) A solution of 22.3 g (0.17 mol) of 1-methylindole in tetrahydrofuran (220 ml) was cooled to -78°C, and 100++1 of a solution of t-butyllithium in pentane having a concentration of 1.7 mol/l was added.The mixture was heated to 25°C and stirred at this temperature for 1.5 hours to obtain a suspension.

25.4 g of methyltrichlorosilane cooled to -78°C
The above suspension was gradually added to a solution of (0.17 mol) in tetrahydrofuran (60 ml). After stirring at room temperature for 14 hours, the white solid was removed by decantation, the solvent was removed using an evaporator and a vacuum pump, and dichloromethyl(2-(1-methylindolyl))silane 32
g was obtained as crystals. Melting point: 60-62°C (under nitrogen atmosphere). Yield 76%.

Infrared absorption spectrum (KBrBr method, cm-') 30
50, 2920.1545.1460.1338.12
70.1) 60-1000, 780-740° 1H-nuclear magnetic resonance absorption spectrum (CDC1, solution, δ
(ppa+)) 1.17 (3H,s, 5iCHs), 3.97
(3H,s, NCR,).

6.94 (IH,s, C=CH), 6.9
-7.7 (4H,re, aroma-tiCH
).

Reference example 2 (dichlorophenyl (2-(1-methylindolyl))
Synthesis of silane) A solution of 6.3 g (48 mmol) of 1-methylindole in tetrahydrofuran (100 ml) was cooled to -78°C, and 28 m+1 of a solution of t-butyllithium in pentane with a concentration of 1.7 mol/1 was added thereto. . Raise the temperature to 25℃,
After stirring at this temperature for 2 hours, a suspension was obtained.

Phenyltrichlorosilane cooled to -78°C 10.2
g (48 mmol) of tetrahydrofuran (40 ml)
The above suspension was gradually added to the solution. After stirring at room temperature for 20 hours, the white solid was removed by decantation and concentrated using an evaporator. The obtained oil was distilled under reduced pressure (0.4 smlg) to give dichlorophenyl (2-(
9.5 g of 1-methylyn(t'IJ)silane was obtained.

Yield 65%. This compound crystallized after vacuum distillation.

Boiling point 146-148℃ 10.4IHg Infrared absorption spectrum (KBr tablet method, cya-') 3045, 29
25.1602.1582.1490.1460.14
22°1355, 1300.1) 10.1075.80
0.730.690.580°555°+H-nuclear magnetic resonance absorption spectrum (CDCh solution, δ(
ppm)) 3.87 (3H,s, NCHs), 6.89 (
LH,s, C=CII).

6.9-7.9 (9H, ra, aromatic
H).

Reference Example 3 (Synthesis of polymethyl(2-(1-methylindolyl))silane) Toluene (15 st) was added to 1.00 g (44 mmol) of metallic sodium under an argon atmosphere, and the temperature was raised to the reflux temperature of toluene. , with vigorous stirring to prepare the sodium disversion.

4.89 g (20 mmol) of dichloromethyl[2(1-(methylindolyl))]silane was added to this dispersion and stirred at reflux temperature for 4 hours. During this time, a purple solid was precipitated. Allowed to cool to room temperature. After that, hexane (100m
l) and filtering the solid under an argon atmosphere;
This was washed with methanol, water, ethanol and hexane in this order. The white solid thus obtained was dried to obtain 1.27 g of polymethyl(2-(1-methylindolyl))silane having an average molecular weight of 5000 (according to GPC). Melting point: 200-208°C. Yield 37%.

Melting point: 200-208°C Infrared absorption spectrum (KBr tablet method, cm-') 3
050, 2920.1490.1460.1350.1
320.1300°1230, 1)00-1000.7
95.745.620°IH-nuclear magnetic resonance absorption spectrum (CDCI, solution, δ (ppm)) -0,4-1,0 (3H, br, 5iCHx), 2
．． 0-4. OC3H, br.

NCH3), 5.8-7.8 (58,br, C=
CH and aromaticll).

Reference example 4 (dichloromethyl[2-(1-(methylindolyl))]
Copolymerization of silane and dichloromethylphenylsilane) 1.38 g (60
n-dodecane (20 ml) was added to 140
The sodium disversion was prepared by raising the temperature to 0.degree. C. and stirring vigorously.

Dichloromethyl [2-(1-(
29,700.73 g (3.0 mmol) of dichloromethylphenylsilane, 5.16 g of dichloromethylphenylsilane (27
A solution consisting of n-dodecane (mmol) and n-dodecane (20+*l) was added dropwise and stirred at 140°C for 6 hours. During this time, intense bubbling occurred and a purple solid precipitated out. After cooling to room temperature, this solid was filtered under an argon atmosphere and extracted with hexane,
Washing was performed with methanol, water, ethanol and hexane in this order. The white solid thus obtained was dried to obtain 0.85 g of copolymerized polysilane having an average molecular weight of 4000 (according to GPC). Yield 33%.

Melting point: 195-198°C Infrared absorption spectrum (KBr tablet method, cm-') 1
480, 1460.1420.1300%1240.1
095.1060.780, 750. 725. 6
90°1!1-Nuclear magnetic resonance absorption spectrum (CDCI, solution,
δ(ppa+) ) 1.2-0.5 (br, 5iCII3), 2.6
−3.4 (br, 'NCll5).

5.8-7.5 (br, C=C)I and aro
matic)l).

Example 1 1.0 g of the polymethyl(2-(1-methylindolyl))silane powder prepared in Reference Example 3 was dissolved in 101 parts of trifluoroacetic acid to obtain a homogeneous solution.

This solution was applied onto a glass plate using a spin code method, and the trifluoroacetic acid was evaporated under a nitrogen atmosphere to give a thickness of 2.
000 thin films were obtained.

When a voltage was applied to this thin film and the current and voltage were measured using the four-probe method, the conductivity was 0. It was OIS/cm.

Example 2 1.0 g of copolymerized polysilane powder prepared in Reference Example 4
was dissolved in 5 ml of trifluoroacetic acid and 5@1 of 1,2-dichloroethane to obtain a homogeneous solution.

This solution was coated on a glass plate using a spin code method, and trifluoroacetic acid and l were added under a nitrogen atmosphere.

The 2-dichloroethane was evaporated to give a 4000 mm thick film.

When a voltage was applied to this thin film and the current and voltage were measured using a four-probe method, the electrical conductivity was found to be 0.0075/by.

Example 3 1.0 g of benzoic acid was added to 1.0 g of polymethyl (2-(1-methylindolyl))silane powder prepared in Reference Example 3.
and 10s+1 of 1,2-dichloroethane were added to obtain a homogeneous solution.

This solution was applied onto a glass plate using a spin code method to obtain a thin film with a thickness of 3000 mm. This thin film was dried at 70° C. for 1 hour under a nitrogen atmosphere.

When a voltage was applied to this thin film and the current and voltage were measured using a four-probe method, the conductivity was found to be 0.001 S/2.

Example 4 1.0 g of polymethyl (2-(1-methylindolyl)) silane powder prepared in Reference Example 3 was dissolved in 10+ wl of 1,2-dichloroethane, and the resulting solution was molded into glass using a spin code method. It was applied onto a plate to obtain a thin film with a thickness of 4,000 people.

After drying this thin film at 70° C. for 1 hour in a nitrogen atmosphere, trifluoroacetic acid vapor was sprayed onto the thin film in a nitrogen gas stream. Thereafter, trifluoroacetic acid adhering to the thin film surface was removed under reduced pressure and a nitrogen gas stream, and the film was dried again at 70° C. for 1 hour under a nitrogen atmosphere.

When a voltage was applied to the thin film thus prepared and the current and voltage were measured using the four-probe method, the electrical conductivity was 0.00.
It was 23/cm.

Comparative Example 1 1.0 g of the polymethyl (2-(1-methylindolyl))silane powder prepared in Reference Example 3 was dissolved in 10 ml of 1,2-dichloroethane, and the resulting solution was applied to a glass plate using a spin code method. It was applied onto a plate to obtain a thin film with a thickness of 4,000 people.

This thin film was dried at 70°C for 1 hour under a nitrogen atmosphere.

When a voltage was applied to this thin film and the current and voltage were measured using a four-probe method, the electrical conductivity was I x 10-''S/cs.

Claims (6)

[Claims] (1) General formula (Ia) ▲Mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^1 and R^2 are each independently an alkyl group, an aryl group, or an aralkyl group, and R^3 is hydrogen , represents an alkyl group, an aryl group, or an aralkyl group. A method for producing conductive polysilane, characterized in that it is treated with a dopant represented by: (2) The method for producing conductive polysilane according to claim 1, wherein the dopant is trifluoroacetic acid. (3) The method for producing conductive polysilane according to claim 1, wherein the dopant is benzoic acid. (4) General formula (Ia) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^1 and R^2 are each independently an alkyl group, an aryl group, or an aralkyl group, and R^3 is hydrogen , an alkyl group, an aryl group, or an aralkyl group) and the general formula (I b) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^4 and R^5 are respectively (independently representing an alkyl group, an aryl group, or an aralkyl group) and a structural unit represented by 1. A method for producing conductive polysilane, which comprises treating with a dopant represented by (representing a substituted alkyl group). (5) The method for producing conductive polysilane according to claim 4, wherein the dopant is trifluoroacetic acid. (6) The method for producing conductive polysilane according to claim 4, wherein the dopant is benzoic acid.