JPH09157358A - Luminescent silicone polymer compound and its preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a novel silicone polymer compd. which emits light at wavelengths in a visible region and can be used as a display element by comprising a methylphenylsilane monomer unit and a thiophene monomer unit. SOLUTION: An oligothiophene (microthiophene), having on its terminal a chlorosilyl group, represented by formula I (wherein R represents a 4-8 C straight-chain alkyl; and (n) is 5 to 50), for example, is polycondensed with methylphenyldichlorosilane to prepare a polysilane represented by formula II (wherein R represents a 4-8 C straight-chain alkyl; (m) represents the degree of polymn. of a methylphenylsilane monomer unit and is 50 to 500; and (n) represents the degree of polymn. of a thiophene monomer unit and is 5 to 50) and having a wt.-average mol.wt. (in terms of polystyrene of 10,000 to 100,000 ad determined by gel permeation chromatography(GCP). This reaction is conducted by mixing the microthiophere with the methylphenyldichlorosilane in an org. solvent, adding a reducing agent such as metallic sodium, and conducting dehalogenation polycondensation at a temp. around the boiling point of the solvent.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention provides a novel silicon polymer compound which is useful as a light emitting material, a semiconductor material and the like, and particularly emits light in the visible region, and a method for producing the same.

[0002]

2. Description of the Related Art A silicon-based polymer compound (hereinafter referred to as polysilane) is a polymer whose main chain skeleton is composed of Si-Si bonds, and emits light and emits light due to a σ-conjugated electronic structure extending along the main chain. It is known that properties suitable for semiconductors such as photoconductivity are exhibited. In particular, regarding the light emitting function of linear polysilane, it is highly useful as a fluorescent material because it emits light efficiently because the electron transition during excitation is a direct transition type, but polysilane is used as a material for display devices. If the emission wavelength is 400 nm
It is necessary to be in the above visible region. However, almost all the emission wavelengths of the conventionally known polysilanes are in the ultraviolet region. For example, poly (methylphenylsilane) which is a typical polysilane has 353 nm,
Poly (di-n-hexylsilane) has only been observed to emit light with a maximum wavelength of 337 nm [RD Mille
r, Chemical Reviews, 89, No. 6, (1989)].

[0003]

As described above, the polysilanes that have been studied so far show only fluorescence in the ultraviolet region. Therefore, there is a need for a compound that emits light in the visible region and can be used as a display device. Therefore, as a result of intensive studies, the present inventors have found that a novel polysilane containing oligothiophene at the terminal has a function of emitting light at a wavelength in the visible region, and completed the present invention.

[0004]

The present invention is a polysilane represented by the formula [1].

[0005]

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(R represents a linear alkyl group having 4 to 8 carbon atoms, and n represents a positive number of 5 to 50)

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The polysilane represented by the formula [1] in the present invention is a novel compound which has not been published in the literature. Formula [1]
When R is specifically shown, a butyl group, a pentyl group,
Hexyl group, heptyl group and octyl group, high solubility in organic solvents, excellent processability for thin film production, etc., and because a thin film with high mechanical strength can be obtained, hexyl group, heptyl group and octyl group Is preferable, and a hexyl group is particularly preferable. Further, m and n are the polymerization degrees of the methylphenylsilane monomer unit and the thiophene monomer unit, respectively, m is a positive number of 50 to 500 and n is a positive number of 1 to 50. The gel permeation chromatography of the polysilane in the present invention (hereinafter referred to as G
The weight average molecular weight (converted to polystyrene) based on PC is preferably 10,000 to 100,000, and more preferably 10,000 to 50,000.

The polysilane in the present invention is produced, for example, by polycondensing an oligothiophene (hereinafter referred to as macrothiophene) represented by the formula [2] containing a chlorosilyl group at the terminal with methylphenyldichlorosilane.

[0009]

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(R represents a linear alkyl group having 4 to 8 carbon atoms, and n represents a positive number of 1 to 50)

The macrothiophene is also a novel substance.
For example, a polythiophene compound represented by the formula [5] obtained by Grignard polymerization of dibromothiophene represented by the formula [3] and monobromothiophene represented by the formula [4] is added in the presence of a palladium chloride catalyst. The macrothiophene is produced by reacting with carbon tetrachloride.

[0012]

Embedded image

(R ¹ represents a linear alkyl group having 4 to 8 carbon atoms)

[0014]

[Chemical 6]

[0015]

Embedded image

(R ¹ represents a linear alkyl group having 4 to 8 carbon atoms, and n represents a positive number of 1 to 50)

Next, the method for producing polysilane according to the present invention will be described. Polysilane is produced by mixing the macrothiophene and methylphenyldichlorosilane in an organic solvent and adding a reducing agent to carry out dehalogenative condensation polymerization. Examples of the reducing agent include metallic sodium, metallic potassium and metallic lithium, and metallic sodium is preferable. The organic solvent can be used without particular limitation as long as it dissolves macrothiophene, methylphenyldichlorosilane and the resulting polysilane, and specific examples thereof include toluene, xylene, tetrahydrofuran, benzene and ethylbenzene, and preferably toluene. , Xylene and tetrahydrofuran, particularly preferably toluene.

The weight ratio of macrothiophene to methylphenyldichlorosilane in the above reaction is 0.01.
It is preferably from 20 to 20% by weight, particularly preferably from 0.05 to 10% by weight. The reaction temperature is preferably in the vicinity of the boiling point of the solvent used, for example, 100 to 110 ° C. when using toluene and 13 when using xylene.
0-140 degreeC is preferable. The reaction time is preferably 30 minutes to 5 hours, particularly preferably 1 to 2 hours. If the reaction time is longer than 5 hours, the generated polysilane may be decomposed.

Further, the polysilane can be purified by filtering the reaction product and reprecipitating it with methanol and n-hexane, for example.

The polysilane obtained according to the present invention is 58
It exhibits visible light emission having a maximum wavelength near 0 nm, and is useful as a light emitting material and a semiconductor material.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to embodiments. Reference Example Production of Macrothiophene Magnesium metal 0.24 in a 50 ml eggplant-shaped flask.
g (10.0 mmol) and a magnetic stirrer were put therein, and the inside of the flask was put into a dry nitrogen atmosphere. 10 ml of tetrahydrofuran was added with a syringe, and 3.26 g (10.0 mmol) of 2,5-dibromo-3-hexylthiophene was added with stirring with a magnetic stirrer. The Grignard reaction proceeded while generating heat, and after 30 minutes, the metallic magnesium was completely consumed and the reaction was terminated, resulting in a uniform transparent solution. 0.28 g (1,0 mmo of 2-bromo-5-methylphenylhydrosilylthiophene was added thereto.
1) and 10 ml of a tetrahydrofuran solvent were added and stirred. Then, 0.24 g (0.33 mol% based on 2,5-dibromo-3-hexylthiophene) of nickel chloride diphenylphosphinoethane as a catalyst was added and stirred. Polymerization started immediately and an exotherm occurred. After the reaction was carried out for 1 hour, the solution turned reddish brown and the by-product magnesium bromide was precipitated.

In order to purify the produced polymer, the above reaction solution was poured into a separatory funnel containing 100 ml of 5% hydrochloric acid and shaken. Since a brown crude polymer was deposited on the aqueous layer,
This was separated, redissolved in 50 ml of tetrahydrofuran again, and re-precipitated by pouring the polymer solution into 300 ml of acetone. This was collected with a glass filter and dried under reduced pressure to obtain 0.59 g of a purified polymer. The yield was 32%. The number average molecular weight determined by GPC was 5,050 (dispersion degree 1.24). The degree of polymerization n was confirmed to be 30 from the integral ratio of the proton nuclear magnetic resonance spectrum. The infrared absorption spectrum of the obtained polymer is shown in FIG. C-H stretching vibration of thienyl group at 3,030 cm ^-1 , 2,956, 2,927, 2,8
Hexyl group C-H stretching vibration at 57 cm ^-1 , 2,130
Si-H stretching vibration of the terminal groups in cm ^-1, is observed characteristic absorption of C-S stretching vibration of the thiophene ring to 825cm ^-1, the resulting polymer - has a hydrosilyl group-terminated main chain 3- It was confirmed to be a polythiophene compound represented by the above formula [5] composed of a hexylthienyl group.

Next, 0.59 g of the polythiophene compound obtained above was placed in a 100 ml eggplant type flask whose atmosphere was replaced with dry nitrogen, and dissolved in 20 ml of carbon tetrachloride. After adding 10 mg of powder of palladium chloride, the mixture was heated under reflux for 24 hours while stirring with a magnetic stirrer. After allowing to cool to room temperature, the catalyst was removed by filtration. The polymerization solution was dried under reduced pressure to obtain 0.60 g of dark purple solid polymer. The yield was 100%. The number average molecular weight determined by GPC is 5,50.
It was 0 (dispersion degree 1.33), and the degree of polymerization n was recognized to be 30 from the integral ratio of the proton nuclear magnetic resonance spectrum. The infrared absorption spectrum of the obtained polymer is shown in FIG.
C-H stretching vibration of the thienyl group at 3,055 cm ^-1 ,
C-H stretching vibration of hexyl groups 956,2,927,2,857cm ^-1, C-S of the thiophene ring to 825cm ^-1
Although characteristic absorption of stretching vibration was observed, the Si—H stretching vibration of 2,130 cm ⁻¹ , which was observed before carrying out this reaction, had completely disappeared. Further, when a qualitative test for halogen was conducted by the Weilstein method, it was positive. As a result, it was shown that all the terminal hydrosilyl groups of the obtained polymer were chlorinated, and it was confirmed that the polymer was α-methylphenylchlorosilyl-poly (3-n-hexylthiophene) represented by the formula [2]. confirmed.

Example 1 A 500 ml four-necked flask equipped with a dropping funnel, a ball cooling tube and a glass tube for temperature measurement was equipped with a stainless steel stirring blade, and 4.30 g (187 mmol) of granular metallic sodium was added. The inside was made into a dry nitrogen gas atmosphere. 160 ml of dehydrated and purified toluene
Was added with a syringe, and toluene was boiled by heating with a heater, followed by stirring at high speed to disperse metallic sodium as fine particles. Next, 0.11 g each of α-methylphenylchlorosilyl-poly (3-n-hexylthiophene) having a number average molecular weight of 5500 (polymerization degree n = 30) and methylphenyldichlorosilane produced in Reference Example were prepared.
0.8 g (57 mmol) was taken, dissolved in 20 ml of toluene, and slowly dropped from the dropping funnel over 30 minutes.
At this time, the dropping rate and the heating amount were adjusted so that the temperature of the reaction solution was 100 to 110 ° C. After all the raw material solution was supplied, the mixture was heated under reflux for 1 hour to allow the polymerization reaction to proceed. After cooling to room temperature, the precipitated sodium chloride and unreacted metallic sodium were filtered, and the polymerization solution was mixed with 5
The polymer was precipitated by pouring it into 00 ml of methanol. 100 ml of the obtained crude product was added to tetrahydrofuran.
After re-dissolving in, the solution was reprecipitated by adding 500 ml of n-hexane. The precipitated polymer was filtered with a glass filter and then dried under reduced pressure to obtain a purified polymer. The yield was 31%. The obtained polymer was detected at a wavelength of 4
As a result of GPC analysis at 40 nm, the polysilane produced as shown in FIG. 3 clearly has a higher molecular weight than that of the starting compound α-methylphenylchlorosilyl-poly (3-n-hexylthiophene). Has a weight average molecular weight of 32,100 (dispersion degree of 1.4
0). Further, according to the UV-visible absorption spectrum shown in FIG. 4, the absorption due to the σ → σ * transition of the polysilane skeleton is shown at the maximum absorption wavelength of 339 nm, and the maximum due to the π → π * transition of the thiophene chain is shown. Absorption is 440
Observed at nm. From the above results, it was confirmed that the polymer obtained by the present invention was a copolymer having a methylphenylsilane monomer unit and a thiophene monomer unit as constitutional units.

On the other hand, the absorbance at the maximum absorption wavelength of each absorption band in the UV-visible absorption spectrum is determined by the extinction coefficient ε _Si per silicon unit of poly (methylphenylsilane).
= 9,300, the molar extinction coefficient ε _{T of} the α-methylphenylchlorosilyl-poly (3-n-hexylthiophene) used as the raw material was divided by the molar extinction coefficient ε _T = 95,500 (actual measurement value) to obtain the copolymer composition, In the above formula [1], m = 218, n =
It became 30. The theoretical molecular weight of the copolymer was calculated from this composition to be 31,222, which was almost the same as the weight average molecular weight determined by GPC. Therefore, this compound was confirmed to be an AB type copolymer having a polysilane monomer unit and a polythiophene monomer unit as constitutional units. The obtained copolymer has a wavelength of 592 nm when excited by light of 420 nm.
Was observed (Fig. 5). In addition, according to the excitation spectrum measured to examine the energy order giving this emission, the maximum peaks appeared at 469 nm and 340 nm. This means that the order of giving visible emission is not only the π → π * transition (maximum wavelength 469 nm) of the thiophene chain,
It is shown that it also exists in the σ-conjugated system (maximum wavelength 340 nm) of the polysilane skeleton. From the above results, it was confirmed that the compound of this example is a novel polysilane having an excitation order that gives visible light emission to two segments of a π-conjugated system and a σ-conjugated system, and has suitable properties as a light emitting material. .

Example 2 α-methylphenylchlorosilyl-poly (3-n-hexylthiophene) having a degree of polymerization of n = 30 and methylphenyldichlorosilane were respectively prepared as 1.
0 g, 11.6 g (61 mmol) of toluene 50
Polymerization was performed in the same manner as in Example 1 except that the raw material dissolved in ml was used to obtain a copolymer with a yield of 11%. GP
The molecular weight according to C was 25,100 (dispersion degree 1.82). When the copolymer composition was calculated in the same manner as in Example 1, m = 1.
15, n = 30. The ¹³ C nuclear magnetic resonance spectrum of the obtained compound is shown in FIG. According to FIG. 6, -7 pp
A peak attributed to the carbon of the hexyl group was observed at m and a carbon of the hexyl group at 14 to 32 ppm, and it is clear that this compound is a polymer composed of a polymethylphenylsilyl segment and a 3-hexylthienyl segment. In addition, this compound is 59 when excited at 420 nm.
A visible light emission of 5 nm was observed, and it was confirmed that the material has suitable properties as a light emitting material.

Example 3 α-Methylphenylchlorosilyl-poly (3-n-octylthiophene) having a degree of polymerization of n = 20 and methylphenyldichlorosilane were each added to 0.2%.
52 g, 10.3 g (54 mmol) was taken and toluene was 3
Polymerization was performed in the same manner as in Example 1 except that the raw material dissolved in 0 ml was used, and a copolymer was obtained with a yield of 25%. Molecular weight by GPC is 35,500 (dispersion degree 1.4
5). When the copolymer composition was calculated in the same manner as in Example 1, it was m = 264 and n = 20. The compound is 4
Visible light emission of 590 nm was observed when excited at 20 nm, and it was confirmed to have suitable properties as a light emitting material.

[0028]

INDUSTRIAL APPLICABILITY The polysilane according to the present invention is a novel compound useful as a light emitting material and a semiconductor material. Since it has a light emitting property particularly in the wavelength region of the visible region, it is a very useful material which can be used for display devices and the like. Is.

[Brief description of the drawings]

FIG. 1 shows an infrared absorption spectrum of polythiophene obtained in Reference Example.

FIG. 2 shows an infrared absorption spectrum of macrothiophene obtained in Reference Example.

FIG. 3 shows the polysilane obtained in Example 1 and the starting compound α-methylphenylchlorosilyl-poly (3-
The gel permeation chromatograph (GPC) analysis chart of (n-hexyl thiophene) is shown.

FIG. 4 shows an ultraviolet-visible absorption spectrum of the polysilane obtained in Example 1.

FIG. 5 shows emission and excitation spectra of polysilane obtained in Example 1.

FIG. 6 shows a ¹³ C nuclear magnetic resonance spectrum of the polysilane obtained in Example 2.

Claims (2)

[Claims] 1. A silicon-based polymer compound represented by the formula [1] having a methylphenylsilane monomer unit and a thiophene monomer unit as constitutional units. Embedded image (R represents a linear alkyl group having 4 to 8 carbon atoms, m is 50
A positive number of ˜500 and n represents a positive number of 5 to 50) 2. A silicon-based polymer compound according to claim 1, wherein oligothiophene represented by the formula [2] containing a methylphenylchlorosilyl group at the terminal and methylphenyldichlorosilane are polycondensed. Manufacturing method. Embedded image (R represents a linear alkyl group having 4 to 8 carbon atoms, and n is 5 to 5.
Indicates a positive number of 50)