JP2800699B2 - Novel branched polysilane and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a branched polysilane useful as a light emitting material, a photoconductive material, a resist material and the like, and a method for producing the same.

[0002]

2. Description of the Related Art It has been revealed that organic polysilanes having a Si-Si bond as a basic skeleton exhibit ultraviolet absorption and emission spectra due to σ-σ conjugation derived from the Si-Si bond in the main chain. In recent years, it has attracted attention as a polymer having a material, a light emitting function, and the like. For example, poly (methyl-n-propylsilane), which is a typical linear polysilane in which Si-Si bonds are two-dimensionally spread, has an emission spectrum having an absorption maximum at 340 nm. In addition, three-dimensional Si-Si
It has been confirmed that network polysilane having a skeleton structure emits light in the visible region. In other words, it has been verified that the physical properties of polysilanes can be controlled by controlling the dimensionality of the silicon skeleton. (Next-generation Industrial Technology: 1st Symposium on Silicon-Based Polymer Materials, 116 (1993) ). In order to develop better silicon-based materials, it is important to design and synthesize advanced molecular structures, but in order to perform advanced molecular design, the molecular skeleton structure can be controlled at a high level. Such a synthesis technique is required. However, the most common wurtz polymerization method (condensation polymerization method of chlorosilanes with an alkali metal) as a synthesis method of polysilane is extremely difficult to control the reaction. For example, when a trichlorosilane having three reaction points is used to form a silicon-silicon bond by the Wurtz polymerization method, many by-products are generated because the Si-Cl reacts at random, and There are problems such as a network structure that is originally irregularly connected. That is, in the Wurtz method, it was practically impossible to control the skeleton structure of the polymer molecule. As described above, there is no example of designing a certain molecular structure in a polysilane having a high-dimensional skeletal structure and synthesizing the polysilane while theoretically controlling the skeletal structure. I was

A polysilane dendrimer can be defined as a polysilane having a regularly branched structure in which the skeleton structure is highly controlled three-dimensionally. It can be a material that can be expected to exhibit excellent optical and electrical properties. As for the synthesis example, there is a disclosure of a polysilane dendrimer that can grow in two directions (preprints of the 68th Spring Meeting of the Chemical Society of Japan, pages 356 and 358 (1994)), but the skeleton structure is three-dimensional. There are no known polysilane dendrimers that are highly controlled and can grow regularly in three directions.

[0004]

DISCLOSURE OF THE INVENTION The present inventors aimed at obtaining a polysilane dendrimer whose molecular skeletal structure is highly controlled and which can be expected to have unique physical properties. As a result of intensive studies on the technology, the inventors succeeded in synthesizing a branched polysilane belonging to the polysilane dendrimer and completed the present invention.

[0005]

According to the present invention, there is provided a compound of the formula [A]

[0006]

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The present invention relates to a branched polysilane represented by the formula (where Me represents a methyl group) (hereinafter referred to as polysilane [A]) and a method for producing the same. The polysilane [A] of the present invention is dissolved in various organic solvents such as benzene, toluene, xylene, n-hexane, chloroform and tetrahydrofuran. The polysilane [A] of the present invention has the formula [1]

[0008]

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Wherein X is a halogen atom and Me is a methyl group, and tris (dimethylhalogenosilyl) methylsilane (hereinafter referred to as a silane compound [1]) represented by the formula [2]

[0010]

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Can be obtained by reacting tris (trimethylsilyl) silyllithium (hereinafter referred to as silyllithium compound [2]) in an inert solvent under an inert gas atmosphere. The halogen atom represented by X in the silane compound [1] preferably includes a chlorine atom and a bromine atom, and the silane compound [1]
Preferred examples include tris (dimethylchlorosilyl) methylsilane and tris (dimethylbromosilyl) methylsilane.

The reaction ratio of the silane compound [1] to the silyllithium compound [2] is such that the theoretical amount of the silyllithium compound [2] is 3 moles per mole of the silane compound [1]. The silyllithium compound [2] can be used in an amount of 2 to 4 mol per 1 mol, and the preferable reaction ratio is 2.5 to 3.5 mol. If the amount is less than 2 moles, the yield of polysilane [A] may decrease. If the amount exceeds 4 moles, decomposition of the product due to side reactions is likely to occur, which adversely affects the yield of polysilane [A]. The silane compound [1] and the silyl lithium compound [2] are both known compounds. Among them, for example, when the silyl lithium compound [2] is separately synthesized and used, the silyl lithium compound [2] as it is or the isolated silyl lithium compound [2] can be reacted with the silane compound [1]. Further, in the method of supplying the silane compound [1] and the silyllithium compound [2], it is preferable to drop the silyllithium compound [2] in an inert solvent of the silane compound [1].

As the inert solvent, an aprotic solvent is preferable, and specific examples thereof include benzene, toluene, xylene, n-hexane, n-octane and tetrahydrofuran. Examples of the inert gas include argon, nitrogen, and the like. The inert solvent is preferably used to such an extent that the concentration of the silane compound [1] becomes 10 mmol / L to 1 mol / L. The reaction temperature is preferably −50 to 50 ° C., more preferably −20 to 30 ° C., and most preferably 0 to 30 ° C. −50 ° C
If it is less than 50 ° C., the reaction rate is not sufficient, and if it exceeds 50 ° C., a side reaction may occur. The reaction time varies depending on the reaction temperature, the reaction solvent and the like, but the reaction is usually completed within 48 hours.

In order to obtain polysilane [A] produced from the reaction solution obtained by the above reaction, a precipitate of by-produced lithium halide is removed from the reaction solution by filtration or decantation, and then the reaction solvent is distilled off under reduced pressure, for example. After removing sublimable side reaction products under heating vacuum,
The residue may be purified by a method such as recrystallization with a poor solvent such as methanol.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. In the examples, the number average molecular weight and the weight average molecular weight were determined by a GPC method (in terms of polystyrene). Example 1 A silyl lithium compound [2] was produced by a known method. That is, 5.05 g (15.7 mmol) of tetrakis (trimethylsilyl) silane was charged into a reactor equipped with a stirrer and an external cooling jacket, and the system was degassed under vacuum and then dried under an argon atmosphere. Add 30 mL of dehydrated and purified tetrahydrofuran, and add methyllithium (0.33 g: 15 mm
ol) in diethyl ether (13.5 mL) was slowly fed into the reactor, and the mixture was stirred at 10 to 30 ° C. for 15 hours under an argon atmosphere to obtain tris (trimethylsilyl) silyl lithium 3.43.
A reaction solution containing g (13.5 mmol) was obtained.

In a separate reactor equipped with a stirrer and an external cooling jacket, 100 mL of toluene and 1.63 g (5 mmol) of tris (dimethylchlorosilyl) methylsilane were charged, and at 0 ° C. under an argon atmosphere, the tris ( A reaction solution containing 3.43 g (13.5 mmol) of trimethylsilyl) silyllithium was added dropwise to the contents in the reactor over 3.5 hours,
The reaction was carried out by stirring at 0 to 10 ° C for 40 hours. Then, the precipitate of by-produced lithium chloride is separated by filtration, the reaction solvent is distilled off under reduced pressure, and the sublimable by-product is removed under heating vacuum, and the residue is recrystallized from methanol, which is a poor solvent. As a result, 0.60 g (0.63 mmol) of polysilane [A] was obtained as a white solid. The isolation yield was 12.5%.

The number average molecular weight of the obtained product is 815.
And the weight average molecular weight is 823 (molecular weight distribution is 1.01)
And the melting point was 248.2-254.6 ° C. The molecular weight distribution is shown in FIG. The theoretical molecular weight of polysilane [A] is 960.80.
Although not in agreement with the above, the number average molecular weight and weight average molecular weight of this type of branched polysilane are usually smaller than the theoretical molecular weight, as is well known. FIG. 2 shows a ²⁹ Si NMR spectrum of the product (measured in NNE mode as a standard in tetramethylsilane (0 ppm) in heavy benzene). FIG. 2 shows that the chemical shift δ (ppm) is −8.76.
(Primary silicon: a), -25.49 (secondary silicon: b), -3
7.13 (tertiary silicon: c) and -119.83 (quaternary silicon:
Each peak in d) is observed at an intensity ratio corresponding to the number of each silicon within an error range, and the obtained polymer is a polysilane dendrimer derivative, the branched polysilane of the present invention, that is, tris [2,2-bis (trimethylsilyl)). [-1,1,3,3,3-pentamethyltrisilyl] methylsilane. This product also showed an ultraviolet absorption maximum at 265 nm.

[0018]

The polysilane [A] of the present invention is highly specific in three dimensions, has a molecular skeleton capable of growing regularly in three directions, and has an ultraviolet absorption maximum due to σ-σ conjugation. It can be expected to exhibit optical and electrical properties, and can be applied as a compound electronic material with excellent light emitting properties, photoelectric conductivity and resist properties, and can be molded into electronic materials because it is soluble in organic solvents. . Therefore,
The polysilane [A] of the present invention can be used as a light-emitting material, a photoconductor, a photoresist, an optical storage material, and the like. In addition, the terminal methyl group of the polysilane [A] of the present invention can be replaced with chlorine by treating it with silicon halide using an aluminum chloride catalyst. It can lead to a connected, larger polysilane dendrimer.

[0019]

[Brief description of the drawings]

FIG. 1 shows the molecular weight distribution of polysilane [A] obtained in Example 1.

FIG. 2 shows ²⁹ SiNM of the polysilane [A] obtained in Example 1.
The R spectrum is shown.

Continuation of front page (56) References JP-A-5-262880 (JP, A) Chemistry, 46-4! (1991) 280-281. ADV. MATER. , 5-6! (1993), 466-468. MACROMOL. SYMP. , 77 (1994), 79-92. (58) Fields investigated (Int. Cl. ⁶ , DB name) C07F 7/08 CA (STN) REGISTRY (STN) WPIDS (STN)

Claims (2)

(57) [Claims] 1. A compound of the formula [A] (Wherein, Me represents a methyl group). 2. Formula (1) (Wherein X represents a halogen atom and Me represents a methyl group) and tris (dimethylhalogenosilyl) methylsilane represented by the formula [2] 3. The method for producing a branched polysilane according to claim 1, wherein tris (trimethylsilyl) silyllithium represented by the following formula is reacted in an inert gas atmosphere in an inert solvent.