JPH1045915A - Visible-responsive silicon polymer and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a novel silicon polymer having in the main chain repeating units each comprising an Si atom and an oligothiophene unit having ethynylene groups at both terminals and having excellent photoconductivity and electric conductivity and response to visible rays. SOLUTION: This polymer has in the main chain repeating units each comprising an Si atom, ethynylene groups and an oligothienylene group. It is obtained by reacting a diethynylsilane (e.g. dihexyldiethynylsilane) with a dihalo- oligothiophene (e.g. dibromobithiophene) in the presence of a catalyst [e.g. tetrakis(triphenylphosphine)palladium]. It is useful as a photoconductor, an electric conductor, a nonlinear optical material or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel visible responsive silicon-based polymer having excellent photoconductivity and conductivity, and a method for producing the same.

[0002]

2. Description of the Related Art Polysilane has been widely studied in the fields of, for example, precursors for ceramics, conductive materials, photoconductive materials (photoconductors), and nonlinear optical materials, and has become an interesting polymer material. .

In the prior art, as a polysilane having only silicon in the polymer main chain, a polymer represented by the following general formula (A) and its properties are described, for example, in Chem. Rev., 8:
9 (1989), 1359, in a review by RDMiller and Michl.

Embedded image [Wherein, R ⁵ and R ⁶ are each a hydrocarbon group. ]

On the other hand, a large number of silicon-based polymers having a silicon atom and a π-conjugated system alternately in the main chain have also been synthesized and are expected to be applied in the same manner as polysilane. For example, reference can be made to Mitsuo Ishikawa, "New Organosilicon Polymer", 1991, p. Further, as an example of a polymer having silicon and a π-conjugated system alternately in the main chain, a polymer having silicon, ethynylene and arylene has been recently reported by RJP Corriu et al. (RJP Corriu et al., J. Organomet et al. .Che
m., 455 (1993) 69-76). The report states that the binding reaction between aryl halide and acetylene proceeds effectively in the presence of a palladium catalyst.
The method of gashira et al. (K. Sonogashira et al., Tetrahedron Let
t., 50 (1975) 4467-4470) is applied to the synthesis of a silicon-based polymer, and various π-electron systems are converted to a silicon-based polymer by reacting a dihalogenated arylene with a diethynyldialkylsilane. It is reported that it can be introduced.

[0005] However, the light absorption of these polymers is basically limited to the ultraviolet region, and the sensitive wavelength such as the photoconductivity is also limited to the ultraviolet region. In applications to photoconductors and the like utilizing photoconductivity, it is common to use a readily available visible light source, and in order to apply silicon-based polymers to them, light absorption, and A measure to achieve the visualization of the sensitive wavelength is desired.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances.
A novel visible-sensitive silicon-based material with a silicon unit in the main chain and an oligothiophene unit with an ethynylene group at both ends, which is extremely useful as a photoconductive material (photoconductor), conductive material, nonlinear optical material, etc. It is an object of the present invention to provide a molecule and a method for producing the molecule.

[0007]

The present invention solves the above-mentioned problems by providing a novel silicon-based polymer having a repeating unit composed of an oligothiophene unit having a silicon atom and an ethynylene group bonded to both ends of a main chain. That is, the present invention provides poly (silyleneethynylene oligothienyleneethynylene). More specifically, the present invention provides the following general formula (1):

Embedded image [Wherein, R ¹ , R ² , R ³ and R ⁴ are each a hydrogen atom or a hydrocarbon group, 1 is a number of 1 or more, m is a number of 2 or more, and n is a number of 2 or more. And a silicon-based polymer having a silicon atom, an ethynylene group, and an oligothienylene group in the main chain as a repeating unit.

In the formula (1), when R ¹ , R ² , R ³ and R ⁴ are a hydrocarbon group, the hydrocarbon group has 1 to 1 carbon atoms.
8 are preferably used, and examples thereof include an alkyl group, an aryl group, and an aralkyl group. The hydrocarbon group may be substituted with an alkoxy group (for example, an alkoxy group having 1 to 6 carbon atoms). The carbon number of the alkyl group is usually 1 to 18, preferably 1 to 10 (for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, etc.). The number of carbon atoms of the aryl group is preferably 6 to 18, more preferably 6 to 10 (for example, a phenyl group and a naphthyl group). The aralkyl group preferably has 7 to 18, more preferably 7 to 10 (for example, an anisyl group and a β-phenethyl group). Among the above-mentioned hydrocarbon groups, in order to obtain a high-molecular-weight silicon-based polymer, in order to improve the solubility in a solvent, a chain-like alkyl group or an alkyl group partially substituted with an alkoxy group is used. Preferably, the group is

The silicon-based polymer (1) in the present invention contains at least one silicon atom in the repeating unit of the main chain. The number of thienyl groups in the main chain repeating unit is at least two. In the silicon-based polymer (1), the terminal group bonded to both terminals of the molecule is any group such as hydrogen, an alkyl group, an aryl group, an alkoxy group, a trialkylsilyl group, an ethynyl group, and an oligothienyl group. Good. Further, the silicon-based polymer (1) may be a cyclic polymer having terminals bonded to each other. Silicon polymer
The weight average molecular weight of (1) is from 500 to 1,000,000.

The silicon-based polymer (1) of the present invention is characterized by having oligothienylene having an ethynyl group at both ends in the polymer main chain as a repeating unit. It is useful as a conductive material (photoconductor), a conductive material, a nonlinear optical material, and the like.

Further, the present invention provides a compound represented by the following general formula (2):

Embedded image [Wherein, R ¹ and R ² are each a hydrogen atom or a hydrocarbon group, 1 is a number of 1 or more, and when 1 is 2 or more, R ¹ and R ² bonded to the respective silicon atoms are May be the same or different. A diethynylsilane represented by the following formula (for example, diethynyldialkylsilane, 1,2-diethynyl-1,1,2,2-tetraalkyldisilane):

Embedded image [Wherein, R ³ and R ⁴ are each a hydrogen atom or a hydrocarbon group, and X is a halogen atom. M is a number of 2 or more, and R ³ and R ⁴ bonded to each thiophene ring may be the same or different. The method for producing the above silicon-based polymer (1), which comprises reacting a dihalogenated oligothiophene on both ends in the presence of a catalyst.

In the formula (2), when R ¹ and R ² are a hydrocarbon group, those having 1 to 18 carbon atoms are preferably used as the hydrocarbon group, and examples thereof include an alkyl group, an aryl group and an aralkyl group. And the like. The hydrocarbon group may be substituted with an alkoxy group (for example, an alkoxy group having 1 to 6 carbon atoms). The number of carbon atoms of the alkyl group is usually 1 to 1
8, preferably 1 to 10 (for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group,
Heptyl group, octyl group, etc.). The carbon number of the aryl group is preferably 6 to 18, more preferably 6
To 10 (for example, a phenyl group and a naphthyl group).
The aralkyl group preferably has 7 to 18 carbon atoms, more preferably 7 to 10 (for example, an anisyl group and a β-phenethyl group). Among the above-mentioned hydrocarbon groups, in order to obtain a high molecular weight silicon-based polymer, a chain alkyl group or a part thereof was substituted with an alkoxy group so as to improve the solubility in the solvent. Desirably, it is an alkyl group.

In the formula (3), hydrogen atoms are usually used for R ³ and R ^{4. In} order to obtain a high-molecular-weight silicon-based polymer, it is necessary to improve the solubility in a solvent. Hydrocarbon groups are used. When R ³ and R ⁴ are hydrocarbon groups, those having 1 to 18 carbon atoms are suitably used as the hydrocarbon group, and examples thereof include an alkyl group, an aryl group, and an aralkyl group. The hydrocarbon group may be substituted with an alkoxy group (for example, an alkoxy group having 1 to 6 carbon atoms). The number of carbon atoms of the alkyl group is usually 1 to 1
8, preferably 1 to 10 (for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group,
Heptyl group, octyl group, etc.). The carbon number of the aryl group is preferably 6 to 18, more preferably 6
To 10 (for example, a phenyl group and a naphthyl group).
The aralkyl group preferably has 7 to 18 carbon atoms, more preferably 7 to 10 (for example, an anisyl group and a β-phenethyl group). Among the above-mentioned hydrocarbon groups, in order to obtain a high molecular weight silicon-based polymer, a chain alkyl group or an alkyl group partially substituted with an alkoxy group is preferable.

In the formula (3), for the halogen atom of X,
Chlorine, bromine, iodine and the like can be mentioned, and preferably bromine is used. As the dithio-oligothiophene at both ends represented by the formula (3), for example, di-bromo-oligothiophene at both ends obtained by reacting highly purified oligothiophene with 2 equivalents of N-bromosuccinimide in chloroform is used. Can be

The reaction between the diethynylsilanes (2) and the oligothiophene dihalogenated at both ends is carried out by dissolving both monomers in a solvent under an inert gas atmosphere in a degassed and dried flask. It is performed by heating and stirring in the presence. The reaction temperature is preferably from 20 ° C to 1
It is 50 degreeC, More preferably, it is 50 to 100 degreeC. The reaction time is, for example, about 0.1 to 48 hours. After completion of the reaction, the solvent-insoluble components and the catalyst were removed by filtration, the solution was taken out and concentrated, and the resulting polymer was separated and precipitated to obtain a weight average molecular weight of 50%.
About 0 to 1,000,000 silicon-based polymer (1) is obtained.

In the reaction, the amount of the dithiohalogenated oligothiophene (3) at both ends may be 0.8 to 1.5 mol, especially about 1 mol, per 1 mol of diethynylsilanes (2). As the solvent used in the above reaction, a trialkylamine such as triethylamine is preferably used. Also,
These trialkylamines and other hydrocarbons, for example, toluene, benzene, xylene, hexane, tetrahydrofuran and the like can be used as a mixture. The amount of the solvent is from 100 to 10,000 per 100 parts by weight of the total of the ethinylsilanes and the dithiohalogenated oligothiophene.
It may be 0 parts by weight.

As the reaction catalyst, various palladium catalysts are preferably used, and more preferably, dichlorobis (triphenylphosphine) palladium and tetrakis (triphenylphosphine) palladium are preferably used. Further, when a small amount of a metal halide such as copper iodide is mixed as a co-catalyst, the reaction yield and the molecular weight may be effectively increased. The amounts of the reaction catalyst and the cocatalyst may be 0.1 to 10 parts by weight and 0.01 to 1 part by weight, respectively, per 100 parts by weight of diethynylsilanes (or double-ended halogenated oligothiophenes).

[0018]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

COMPARATIVE EXAMPLE 1 After replacing a 50 mL two-necked flask equipped with a condenser with nitrogen, 0.170 g (1 mmol) of methylphenyldiethynylsilane was added.
l) and 0.236 g (1 mm) of m-dibromobenzene (manufactured by Tokyo Chemical Industry)
ol) and dissolved in 10 mL of triethylamine.
As a catalyst, tetrakis (triphenylphosphine) palladium (0) (manufactured by Tokyo Chemical Industry) 0.023 g (0.02 mmol),
0.0040 g of copper iodide (manufactured by Wako Pure Chemical Industries) as a co-catalyst
(0.002 mmol) and heated in an oil bath to give 9
Heating and stirring were performed at 0 ° C. (reflux conditions) for 20 hours. After allowing the reaction solution to cool to room temperature, triethylamine was
L was added for dilution. After removing insolubles by filtration, the organic layer was concentrated, and the obtained crude product was subjected to fractional precipitation from a benzene / methanol system to obtain a yellow-white powdery polymer.
Further, the polymer was purified by reprecipitation with benzene / methanol.

As a result, the weight average molecular weight was
As a result, a poly (methylphenylsilyleneethynylene-1,3-phenyleneethynylene) having a molecular weight (Mw) of 5,600 and a dispersion (Mw / Mn) of 1.7 [compound of the following formula (i)] was obtained. The molecular weight is determined by gel permeation chromatography (GPC).
And in terms of polystyrene.

[0021]

Embedded image [In the formula, Me is a methyl group, and Ph is a phenyl group. ]

COMPARATIVE EXAMPLE 2 After replacing a 50 mL two- necked flask equipped with a condenser with nitrogen, 0.248 g (1 mmol) of dihexyldiethynylsilane and 0.242 g of 1,5-dibromothiophene (manufactured by Tokyo Chemical Industry) were added.
mmol) and dissolved in 12 mL of triethylamine. As a catalyst, tetrakis (triphenylphosphine) palladium (0) (manufactured by Tokyo Chemical Industry) 0.023 g (0.02 mmo) was used.
l), and copper iodide (manufactured by Wako Pure Chemical Industries, Ltd.) as a promoter 0.000
After addition of 40 g (0.002 mmol), the mixture was heated in an oil bath and stirred at 90 ° C. (reflux condition) for 20 hours. After the reaction solution was cooled to room temperature, about 10 mL of triethylamine was added for dilution. After removing insolubles by filtration, the organic layer was concentrated, and the obtained crude product was subjected to fractional precipitation from a benzene / methanol system to obtain a yellow-white powdery polymer. Further, the polymer was purified by reprecipitation with benzene / methanol.

As a result, the weight average molecular weight was 65% in yield.
Poly (dihexylsilyleneethynylene-2,5-thienyleneethynylene) with (Mw) 5,600 and dispersion (Mw / Mn) 1.7
[Compound of the following formula (ii)] was obtained. The molecular weight was determined using gel permeation chromatography (GPC).
It was determined in terms of polystyrene.

[0024]

Embedded image [Wherein, Hex is a hexyl group. ]

Example 1 After replacing a 50 mL two-necked flask equipped with a condenser with nitrogen, 0.248 g (1 mmol) of dihexyldiethynylsilane and 2,2'-bithiophene were reacted with 2 equivalents of N-bromosuccinimide. 0.324 g (1 mmol) of dibromobithiophene obtained in the above was charged and dissolved in 12 mL of triethylamine. As a catalyst, tetrakis (triphenylphosphine) palladium (0) (manufactured by Tokyo Chemical Industry) 0.0
After adding 23 g (0.02 mmol) and 0.0040 g (0.002 mmol) of copper iodide (manufactured by Wako Pure Chemical Industries, Ltd.) as a co-catalyst, the mixture was heated in an oil bath and stirred at 90 ° C. (reflux conditions) for 12 hours. Was done. After the reaction solution was cooled to room temperature, about 10 mL of triethylamine was added for dilution. After removing insoluble matter by filtration, the organic layer was concentrated, and the obtained crude product was subjected to fractional precipitation from a benzene / methanol system to obtain a yellow powdery polymer. In addition, this polymer is converted to benzene /
It was purified by reprecipitation with methanol.

As a result, a weight average molecular weight of 35% was obtained.
Poly (dihexylsilyleneethynylene (2,5-bithienylene) ethynylene) (Mw) 4,800 and dispersion (Mw / Mn) 1.6 [compound of the following formula (iii)] were obtained. The molecular weight is determined by gel permeation chromatography (GPC).
And in terms of polystyrene.

[0027]

Embedded image [Wherein, Hex is a hexyl group. ]

Example 2 After replacing a 50 mL two- necked flask equipped with a condenser with nitrogen, 0.248 g (1 mmol) of dihexyldiethylsilane and 2,2 ': 5', 2 "-terthiophene in 2 equivalents of N- 0.406 g (1 mmol) of dibromoterthiophene obtained by reacting bromosuccinimide was charged and dissolved in 15 mL of triethylamine, and tetrakis (triphenylphosphine) palladium (0) (manufactured by Tokyo Chemical Industry) was used as a catalyst. 023 g (0.02 mmol) and 0.0040 g (0.002 mmol) of copper iodide (manufactured by Wako Pure Chemical Industries) as a co-catalyst
Was added, and the mixture was heated in an oil bath and heated and stirred at 90 ° C. (reflux condition) for 5 hours. After the reaction solution was cooled to room temperature, about 10 mL of triethylamine was added for dilution. After removing insoluble matter by filtration, the organic layer was concentrated, and the obtained crude product was fractionated and precipitated from a benzene / methanol system to obtain a brown powder polymer. Further, the polymer was purified by reprecipitation with benzene / methanol.

As a result, the weight average molecular weight was obtained at a yield of 40%.
Poly (dihexylsilyleneethynylene (2,5-tertienylene) ethynylene) having a molecular weight (Mw) of 2,000 and a dispersion (Mw / Mn) of 1.8 [compound of the following formula (iv)] was obtained. The molecular weight was determined by gel permeation chromatography (GP
It was determined in terms of polystyrene using C).

[0030]

Embedded image [Wherein, Hex is a hexyl group. ]

FIG. 2 shows the compound (iv) obtained in Example 2.
3 shows an infrared spectrum chart of the film No. 1.

Example 3 After replacing a 50 mL two-necked flask equipped with a condenser with nitrogen, 0.170 g (1 mmol) of methylphenyldiethynylsilane was added.
l) and 0.324 g (1 mmol) of dibromobithiophene obtained by reacting 2,2'-bithiophene with 2 equivalents of N-bromosuccinimide were charged and dissolved in 12 mL of triethylamine. As a catalyst, tetrakis (triphenylphosphine) palladium (0) (manufactured by Tokyo Chemical Industry)
After adding 0.023 g (0.02 mmol) and 0.0040 g (0.002 mmol) of copper iodide (manufactured by Wako Pure Chemical Industries) as a co-catalyst, the mixture was heated in an oil bath and heated at 90 ° C. (reflux condition) for 12 hours. Heating and stirring were performed. After allowing the reaction solution to cool to room temperature,
About 10 mL of triethylamine was added for dilution. After removing insoluble matter by filtration, the organic layer was concentrated, and the obtained crude product was subjected to fractional precipitation from a benzene / methanol system to obtain a yellow powdery polymer. Further, the polymer was purified by reprecipitation with benzene / methanol.

As a result, a weight-average molecular weight of 25% was obtained.
Thus, poly (methylphenylsilyleneethynylene (2,5-bithienylene) ethynylene) (Mw) of 2,800 and dispersion (Mw / Mn) of 1.6 [compound of the following formula (v)] was obtained. The molecular weight is determined by gel permeation chromatography (G
(PC) in terms of polystyrene.

[0034]

Embedded image [In the formula, Me is a methyl group, and Ph is a phenyl group. ]

Example 4 After replacing a 50 mL two-necked flask equipped with a condenser with nitrogen, 0.170 g (1 mmol) of methylphenyldiethynylsilane was added.
l) and 2,406 ′ (1 mmol) of dibromoterthiophene obtained by reacting 2,2 ′: 5 ′, 2 ″ -terthiophene with 2 equivalents of N-bromosuccinimide,
It was dissolved in 15 mL of triethylamine. As a catalyst,
Tetrakis (triphenylphosphine) palladium (0)
(Tokyo Kasei) 0.023 g (0.02 mmol) and copper iodide (Wako Pure Chemical Industries) 0.0040 g (0.002 mm) as a co-catalyst
ol), the mixture was heated in an oil bath, and heated and stirred at 90 ° C. (reflux condition) for 5 hours. After the reaction solution was cooled to room temperature, about 10 mL of triethylamine was added for dilution. After filtering off insolubles, the organic layer was concentrated,
The obtained crude product was subjected to fractional precipitation from a benzene / methanol system to obtain a brown powdery polymer. Further, the polymer was purified by reprecipitation with benzene / methanol.

As a result, the weight average molecular weight was 26% in yield.
Thus, poly (methylphenylsilyleneethynylene (2,5-tertienylene) ethynylene) (Mw) of 1,200 and dispersion (Mw / Mn) of 1.2 (compound of the following formula (vi)) was obtained. The molecular weight was determined in terms of polystyrene using gel permeation chromatography (GPC).

Embedded image [In the formula, Me is a methyl group, and Ph is a phenyl group. ]

Example 5 A 50 mL two-necked flask equipped with a condenser was purged with nitrogen, and then reacted with 1,2-dichloro-1,1,2,2-tetraethyldisilane and two or more equivalents of ethynylmagnesium bromide. The resulting 1,2-diethynyl-1,
0.324 g (1 mmol) of dibromobithiophene obtained by reacting 0.248 g (1 mmol) of 1,2,2-tetraethyldisilane with 2 equivalents of N-bromosuccinimide was charged to triethylamine. Dissolved in 15 mL. As a catalyst, tetrakis (triphenylphosphine) palladium (0) (manufactured by Tokyo Chemical Industry) 0.0
After adding 23 g (0.02 mmol) and 0.0040 g (0.002 mmol) of copper iodide (manufactured by Wako Pure Chemical Industries) as a co-catalyst, the mixture was heated in an oil bath and heated and stirred at 90 ° C. (reflux conditions) for 5 hours. Was done. After the reaction solution was cooled to room temperature, about 10 mL of triethylamine was added for dilution. After removing insoluble matter by filtration, the organic layer was concentrated, and the obtained crude product was fractionated and precipitated from a benzene / methanol system to obtain a brown powder polymer. Further, the polymer was purified by reprecipitation with benzene / methanol.

As a result, a weight-average molecular weight of 80% was obtained.
(Mw) 6,300, dispersion (Mw / Mn) 2.9, poly (tetraethyldisilyleneethynylene (2,5-bithienylene) ethynylene) [compound of the following formula (vii)] were obtained. The molecular weight is determined by gel permeation chromatography (G
(PC) in terms of polystyrene.

[0039]

Embedded image [In the formula, Et is an ethyl group. ]

Example 6 A 50 mL two-necked flask equipped with a condenser was purged with nitrogen and then reacted with 1,2-dichloro-1,1,2,2-tetraethyldisilane and at least two equivalents of ethynylmagnesium bromide. The resulting 1,2-diethynyl-1,
Dibromoterthiophene obtained by reacting 0.248 g (1 mmol) of 1,2,2-tetraethyldisilane with 2,2 ′: 5 ′, 2 ″ -terthiophene and 2 equivalents of N-bromosuccinimide. 406 g (1 mmol) were charged and dissolved in 15 mL of triethylamine, 0.023 g (0.02 mmol) of tetrakis (triphenylphosphine) palladium (0) (manufactured by Tokyo Chemical Industry) as a catalyst, and copper iodide (0.02 mmol) as a co-catalyst. 0.0040 g (0.002 mmol) made by Wako Pure Chemical
Was added, and the mixture was heated in an oil bath and heated and stirred at 90 ° C. (reflux condition) for 5 hours. After the reaction solution was cooled to room temperature, about 10 mL of triethylamine was added for dilution. After removing insoluble matter by filtration, the organic layer was concentrated, and the obtained crude product was fractionated and precipitated from a benzene / methanol system to obtain a brown powder polymer. Further, the polymer was purified by reprecipitation with benzene / methanol.

As a result, the weight average molecular weight was 85% in yield.
Poly (tetraethyldisilyleneethynylene (2,5-tertienylene) ethynylene) (Mw) 1,900 and dispersion (Mw / Mn) 2.0 [compound of the following formula (viii)] was obtained. The molecular weight was determined in terms of polystyrene using gel permeation chromatography (GPC).

[0042]

Embedded image [In the formula, Et is an ethyl group. ]

FIG. 1 shows the compound (vii) obtained in Example 6.
The ¹ H-NMR chart (in deuterated chloroform) of i) is shown.

Example 7 A 50 mL two-necked flask equipped with a condenser was purged with nitrogen, and then reacted with 1,2-dichloro-1,1,2,2-tetraethyldisilane and two or more equivalents of ethynylmagnesium bromide. The resulting 1,2-diethynyl-1,
0.248 g (1 mmol) of 1,2,2-tetraethyldisilane and 2,2 ': 5', 2 ": 5", 2 "'-quarterthiophene in 2 parts
0.488 g of dibromoquarterthiophene obtained by reacting an equivalent amount of N-bromosuccinimide
(1 mmol) was dissolved in a mixed solvent of 7 mL of triethylamine and 7 mL of toluene. 0.023 g (0.02 mmol) of tetrakis (triphenylphosphine) palladium (0) (manufactured by Tokyo Kasei) as a catalyst, and 0.0040 g (0.002 mmol) of copper iodide (manufactured by Wako Pure Chemical Industries) as a cocatalyst. After the addition, the mixture was heated in an oil bath and heated and stirred at 90 ° C. (reflux condition) for 5 hours. After allowing the reaction solution to cool to room temperature, about 10 mL of toluene was added for dilution. After removing insoluble matter by filtration, the organic layer was concentrated, and the obtained crude product was subjected to fractional precipitation from a THF / methanol system to obtain a brown powdery polymer. Further, this polymer was purified by reprecipitation with THF / methanol.

As a result, the weight average molecular weight was 60% in yield.
(Mw) 18,700 and a dispersion (Mw / Mn) 3.2 of poly (tetraethyldisilyleneethynylene (2,5-quarterthienylene) ethynylene) [compound of the following formula (ix)] were obtained. The molecular weight was determined in terms of polystyrene using gel permeation chromatography (GPC).

[0046]

Embedded image [In the formula, Et is an ethyl group. ]

FIG. 4 shows the polymer (ix) obtained in Example 7.
¹ H-NMR (in heavy THF). Also, ²⁹ Si-N
MR (in deuterated chloroform) was -28.25 ppm one. FIG. 5 shows the F of the polymer (ix) obtained in Example 7.
3 shows a T-IR spectrum. At 2141 cm ^-1 -C≡C-
The characteristic absorption resulting from the above can be clearly confirmed. The spin-coated film of the polymer (ix) obtained in Example 7 has strong light absorption in the visible region, and its light absorption maximum wavelength is 4
25 nm.

Example 8 Photoconductivity (photocurrent) measurement The poly (tetraethyldisilyleneethynylene (2,5-quarterthienylene) ethynylene) obtained in Example 7 was quartz deposited with ITO (Indium Tin Oxide). A sample for evaluation was prepared by spin-coating the substrate at a thickness of 2 to 4 μm and depositing 20 nm of gold thereon. While applying a voltage with the ITO electrode of this sample as a positive bias, monochromatic light obtained by splitting the light of a 300 W xenon (Xe) lamp was irradiated from the ITO electrode side, and the current value change at this time was measured. The value obtained by subtracting the dark current value from the current value during light irradiation was defined as the photocurrent value.
FIG. 6 shows the wavelength dependence of the photocurrent value. (The applied electric field strength is 6 × 10 ⁴ V / cm). It can be seen that the polymer film has a photocurrent peak near 500 nm, which is the absorption edge. These results show that the poly (silyleneethynylene oligothienyleneethynylene) of the present invention is a material having high photoconductivity in the visible region.

Measurement of Absorption Spectrum The polymers obtained in Examples 1 and 2 were dissolved in tetrahydrofuran, and the light absorption spectrum was measured. Also,
For comparison, the absorption spectrum of the polymer of Comparative Example 2 was measured in the same manner. FIG. 3 shows an absorption spectrum chart.
The polymer of the comparative example can be synthesized by an existing technique, but its light absorption is limited to only the ultraviolet region. On the other hand, in Examples 1 and 2 obtained by the present invention, the absorption maximum was extended to a longer wavelength due to the effect of the introduced oligothiophene.
In this case, the wavelength was about 410 to 425 nm, and it was found that the film was sensitive to the visible region.

In addition, these light absorptions are significantly longer than the light absorption wavelength of oligothiophene alone contained in the repeating unit of the polymer. For example, bithiophene normally has an absorption maximum at 320 nm, Example 1 of the present invention has an absorption at 380 to 400 nm, and terthiophene generally has an absorption maximum at 350 nm, while Example 2 of the present invention has an absorption at 410 to 425 nm. This means that in the silicon-based polymer of the present invention, an ethynylene group is bonded to both ends of the oligothiophene, and as a result, the π-electron conjugate system is expanded, and the π-electron conjugate system is bonded by a silicon atom. Therefore, it is considered that some effect is produced and the absorption wavelength is further increased. These results show that the silicon-based polymer of the present invention is a visible-sensitive material.

[0051]

The silicon-based polymer of the present invention is a novel polymer not described in any literature. The silicon-based polymer of the present invention mainly has an oligothiophene unit having an ethynylene group at both ends as a repeating unit of the polymer, so that expression of photoconductivity in a visible region can be expected, It is easy to mold and can be used as a photoconductive material (photoconductor), conductive material, and nonlinear optical material.

Further, according to the method for producing a silicon-based polymer of the present invention, an ethynylene group can be easily bonded to both ends of an oligothiophene unit, thereby making the silicon-based polymer visible responsive. be able to. The visible responsive silicon-based polymer of the present invention can be applied to a charge generation / transport layer in an electrophotographic photosensitive member, a conductive material, a nonlinear optical material, and the like, and its industrial value is extremely large.

[Brief description of the drawings]

FIG. 1 is a diagram showing a ¹ H-NMR spectrum of a visible-responsive silicon-based polymer obtained in Example 6 in deuterated chloroform.

FIG. 2 is a view showing an infrared absorption spectrum of the visible responsive silicon-based polymer film obtained in Example 2.

FIG. 3 is a diagram showing light absorption spectra of the visible responsive silicon-based polymer tetrahydrofuran solutions obtained in Examples 1 and 2 and the silicon-based polymer of Comparative Example 2 in tetrahydrofuran solution.

FIG. 4 is a chart showing ¹ H-NMR spectrum in heavy THF of the visible responsive silicon-based polymer obtained in Example 7.

FIG. 5 is a view showing an infrared absorption spectrum of the visible responsive silicon-based polymer obtained in Example 7.

FIG. 6 is a diagram showing the wavelength dependence of the photocurrent value of an element made of the film of the visible responsive silicon-based polymer obtained in Example 7.

Claims (3)

[Claims] 1. A silicon-based polymer having a repeating unit composed of an oligothiophene unit having a silicon atom in its main chain and an ethynylene group bonded to both ends. 2. General formula (1): [Wherein, R ¹ , R ² , R ³ and R ⁴ are each a hydrogen atom or a hydrocarbon group, 1 is a number of 1 or more, m is a number of 2 or more, and n is a number of 2 or more. And a silicon-based polymer having a silicon atom, an ethynylene group, and an oligothienylene group in the main chain as a repeating unit. 3. The method for producing a silicon-based polymer according to claim 1, wherein the diethynylsilanes and the oligothiophene dihalogenated at both ends are reacted in the presence of a catalyst.