JP2002128895A - Optically active organic silicon copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optically active organic silicon copolymer at low cost which has a structure of an organic substituent containing chiral center directly bonding to a silicon. SOLUTION: The copolymer is shown by the general formula (wherein R1 and R2 is equal or different, an alkyl, an aralkyl, an aryoxyalkyl, or alkyl ether group; R* is equal or different, a chiral alkyl group having a branch structure at a β-position; 0.001<=x<=0.999; n is 10-100,000).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optically active organic polysilane which is expected to have thermochromism, piezochromism, electroluminescence, enantiomer molecular recognition ability, or one-dimensional quantum wire semiconductor, physical properties and functions as an exciton substance. Related to polymers.

[0002]

2. Description of the Related Art Many organic silicon compounds are industrially useful, such as a surface treatment agent, a water-repellent oil agent, an electrical insulator, a heating medium, and a precursor of a ceramic material. It is a polymer contained in. In recent years, solvent-soluble organic polysilanes, whose main chain skeleton is composed of only silicon, have attracted attention as a new type of functional material. Photoresists, optical waveguide materials, precursors of silicon carbide, electrophotographic photosensitive materials Numerous research examples have been developed for applications such as bodies, nonlinear optical materials, and luminescent materials.
Organic polysilanes generally have an S around 300 to 400 nm.
It has an ultraviolet absorption band based on a main chain skeleton unique to an i-Si chain. The absorption of the main chain of a conventional polysilane in a solution at room temperature is a molecular absorption coefficient of about 5000 to 8000 (monomer unit / liter) ^-1 cm ^-1 and a half width of 0.5 to 0.6 eV (about 40 to 6 eV).
0 nm), whereas the half-width of the main chain emission in a solution at room temperature is 0.1 to 0.2 eV (about 10 to 20 nm).
And it is considerably narrower than the main chain absorption. In other words, the emission spectrum shape of organic polysilane is usually
There is no mirror image relationship as seen in the light emission phenomenon. Many researchers have thought that the cause of this phenomenon is that a single main chain of organopolysilane is formed by a conformational defect, a trans-zigzag with various conjugation lengths, or a slow helical segment close to it. Is a chain-like linked body. In other words, the main-chain absorption width of the organic polysilane that is usually observed is a manifestation of the superposition of these segment main-chain absorptions having various absorption maxima, and when the main-chain absorption band is photoexcited, it becomes the segment with the lowest excitation energy. It causes energy transfer and emits light from it. Therefore, the properties may have been changed due to many defects in the main chain, not the physical properties inherent in the conventional organic polysilane substance. Since organic polysilane is a polymer in which the main chain itself is composed of only silicon, the main chain is easily decomposed by irradiation with ultraviolet light, and the reduction of the molecular weight or the siloxane conversion easily proceeds. Actually, an application example as a photoresist utilizing this is reported. Therefore, organic polysilanes are unsuitable for application as light-related functional materials such as electrophotographic photoreceptors, non-linear optical materials, and luminescent materials. However, in view of the fact that it exhibits absorption and emission in the ultraviolet region and that a polymer soluble in a solvent can be easily obtained by relatively simple chemical synthesis, the light- It is very valuable and attractive as a model material for basic research on electrical properties, and is expected to be marketable as a polymer standard material. On the other hand, as a polymer material that recognizes enantiomers, the main chain has one-way helicity, such as poly (triphenylmethyl methacrylate) and poly (diphenylpyridylmethyl methacrylate) synthesized using spartin-butyllithium as a polymerization initiator. Carbon skeleton polymers are known [for example, Y. Okamoto (Y.Ok
amoto), Journal of American Chemical Society (J. Am. Chem. Soc.), Volume 103, Volume 6
971 (1981)]. These organic polymers having one-way helicity are marketed as column materials for high-performance liquid chromatography for separating and separating enantiomers in a form actually supported on the surface of silica gel [Daicel Chemical Co., Ltd. Chiralpak-OT, Chiralpak-OP]. However, these poly (triphenylmethyl methacrylate) -based materials have a fatal drawback that the side chain portion fixing the main chain helical structure is eliminated and the ability to recognize enantiomers is lost at the same time. If the silicon main chain skeleton and hydrocarbon side chain of organic polysilane can take advantage of the characteristics of being resistant to hydrolysis and solvolysis, high-performance liquid chromatography usually used in dark places and under deoxygenation conditions It can be used as a column material for chromatography (abbreviated as HPLC) and gas chromatography (abbreviated as GC). Further, it is expected that the resistance to oxygen is further improved as compared with the organic polysilane in the case of an optically active organic polysiloxane structure. For example, when a thermodynamically unstable organic polysilane skeleton is oxidized, it is thought that it is ultimately converted into a thermodynamically stable optically active organic polysiloxane, but the chirality of the main chain is still high. The ability to recognize the enantiomer derived from is still retained, and therefore, it can be expected that it has properties that can be practically used for long-term repeated use.

At present, as a means for separation and analysis by HPLC,
Most of the column materials for enantiomer recognition that can be used even under reversed phase conditions are derived from biological substances, and most of them are alkyl derivatives having an amide bond. Therefore, there still remains a problem of column degradation due to hydrolysis. Here, if it is derived from a chlorosilane-based material having an optically active substituent, or if an optically active organic polysilane having the helicity of the main chain skeleton itself can be supported on a carrier, it can be used as a CSP for HPLC or a CSP for GC. Open applications. At present, such organic polysilanes or organic polysiloxanes are not known. Recently, a single helical (constant winding direction and uniform pitch) polysilane that is thermally very stable in solution has been reported, and 4 eV (320
(nm), a very steep UV / circularly polarized light (CD) absorption and fluorescence spectrum characteristic having a half width of 0.10 eV (8 nm) was reported. Since this single helix polysilane exhibits ideal exciton optical response spectrum characteristics, a quantum wire semiconductor soluble in an organic solvent (thin wire width of 0.1 mm).
5 nm) and as an ideal one-dimensional exciton material [see, for example, M.S. Fujiki (M.Fujik)
i), Journal of American Chemical Society, Vol. 116, No. 6017 (1994),
M. M. Fujiki, Applied Physics Letters, 65, 3251 (1994)].

[0004]

As described above, a single helix polysilane is known to have excellent exciton optical response spectrum characteristics. However, to realize this polysilane, an enantiomerically pure right-handed Type ([R]-
) Or a left-handed ([S]-)) homopolymer obtained by desalting and condensing with sodium metal from a special organic dichlorosilane having a chiral alkyl group in the side chain. In particular, in order to give a very steep exciton optical response spectrum and obtain a polymer structure having a very stable helical structure, the chiral side chain group must be in the β-position or γ-position.
The structure had to have a branched structure at the position. Since the raw materials of these [R] -forms or [S] -forms are very expensive, in order to reduce the production cost, even if the optical purity is somewhat low, or even if the amount of the chiral monomer used is reduced, There was a need to synthesize a unidirectional helical structure with the same exciton optical response spectrum characteristics as the homopolymer. An object of the present invention is to provide an enantiomer recognition material,
In particular, as a material for HPLC and GC CSPs, and as a model standard for one-dimensional semiconductor and quantum wire structure properties research, it has a structure in which an organic substituent containing a chiral center is directly bonded to a silicon atom. An object of the present invention is to provide an optically active organic silicon polymer group in which a helix is stably maintained at a lower cost.

[0005]

SUMMARY OF THE INVENTION In general, the present invention relates to an optically active organosilicon polymer copolymer, and has the following general formula (2):

[0006]

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(Wherein R ₁ and R ₂ are the same or different and each represents an alkyl group, an aralkyl group, an aryloxyalkyl group,
Or an alkyl ether group and R ^* are the same or different, β-
Represents a chiral alkyl group having a branched structure at a position, and x represents 0.001 ≦ x ≦ 0.999.) A silicon unit having an optically active chiral organic substituent represented by the following formula: Included in part, the number of n is 10 to 10000
It is characterized by being in the range up to 0.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below.

The basic invention of the present invention relates to another optically active organosilicon polymer copolymer, and has the following general formula (Formula 3):

[0010]

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(Wherein R ₁ and R ₂ are the same or different and each represents an alkyl group, an aralkyl group, an aryloxyalkyl group,
Or an alkyl ether group, R ₃ is an achiral alkyl group having a branched structure at the β-position, R ^* is a chiral alkyl group having a branched structure at the β-position, and has an (R) -configuration or (S) -configuration. And x is 0.001 ≦ x ≦ 0.999
Is included in a part of the main chain skeleton and has an optically active chiral organic substituent introduced therein, and the number of n is in the range of 10 to 100,000.

The basic invention is characterized by a silane monomer unit having an achiral structure having a branched structure at the β-position, and a silane monomer having a branched structure at the β-position and having a chiral structure having an optical purity of 100%. That is, it is a polysilane copolymer with a monomer unit. On the other hand, a feature of the present invention is that a silane monomer unit having a chiral structure having a (S) configuration having a branched structure at the β-position and a chiral monomer having an (R) configuration having a branched structure at the β-position. Although the ratio to the silane monomer unit having a structure is slightly larger than 1/1, the polysilane copolymer is a small deviation. In other words, it is a polysilane copolymer in which a racemic copolymer of a silane monomer having a chiral structure contains a slight excess of a chiral silane monomer unit having an (R) configuration or an (S) configuration. is there. That is, it is a polysilane copolymer composed of a chiral silane monomer having poor optical purity.

First, the above-described basic invention will be described more specifically with reference to synthesis examples. Si used in the present invention
Chlorosilanes containing an asymmetrically substituted optically active group having two —Cl bonds are synthesized based on the following general reaction formula (Formula 4). The specific synthesis method and analysis result are described in Japanese Patent Application Nos. 5-202474 and 5-20252.
No. 8 is described in each specification.

[0014]

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Et ₂ O represents diethyl ether.

The basic invention and the present invention
And R₁ And R_Two Examples of alkyl groups among the groups represented by
As CH_Three , C_Two H_Five , N-C_Three H₇ , N-C_Four 
H₉ , N-C_Five H₁₁, N-C₆ H₁₃, N-C₇ H_Fifteen, N
-C₈ H₁₇, N-C₉ H₁₉, N-C_TenH_{twenty one}, N-C₁₁H
_{twenty three}, N-C₁₂H_{twenty five}, N-C₁₃H₂₇, N-C₁₄H₂₉, N-
C_FifteenH₃₁, N-C₁₆H₃₃, N-C₁₇H₃₅, N-C
₁₈H₃₇, N-C₁₉H₃₉, N-C ₂₀H₄₁Is mentioned. Ma
Examples of aralkyl groups include CH_Two CH_Two Ph (Ph
Represents a phenyl group. Hereinafter the same), CH_Two CH_Two CH_Two 
Ph, CH_Two CH_Two CH_Two CH_Two Ph. Ma
Examples of aryloxyalkyl groups include CH_Two CH
_Two OPh, CH_Two CH_Two CH_Two OPh, CH_Two CH_Two C
H_Two CH_Two OPh. And alkylate
Examples of the group_Two CH_Two OCH_Two CH_Two OC_Two
H_Five , CH_Two CH_Two O (CH_Two CH_Two O)_Two C_Two H_Five But
No. In the present invention, R^*Group represented by
C, (R) -R^*Examples of the group represented by the following formula
Each group represented by (Chem. 5) is exemplified.

[0017]

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On the other hand, examples of the group represented by (S) -R ^* include the groups represented by the following formula (Formula 6).

[0019]

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In the present invention, examples of the group represented by R ₃ include groups represented by the following formula (Formula 7).

[0021]

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The optically active polysilane copolymer of the basic invention is desalted and copolymerized with the corresponding optically active dichlorosilane, optically inactive dichlorosilane and metallic sodium in toluene to obtain the corresponding optically active polysilane copolymer. The compound is synthesized by the following formula (Formula 8).
At that time, the winding property of the helix is determined only by the absolute configuration of the optically active dichlorosilane used. That is, (S)
By incorporating an optically active dichlorosilane having a chiral alkyl group in a part of the copolymer, the copolymer has the same winding property as a homopolymer that can be synthesized only from an optically active dichlorosilane having a chiral alkyl group in an (S) -configuration. Become. Conversely, (R)
By incorporating an optically active dichlorosilane having a chiral alkyl group in a part of the copolymer, the copolymer has the same winding property as a homopolymer that can be synthesized only from an optically active dichlorosilane having a chiral alkyl group in an (R) configuration. Become.

[0023]

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The copolymer of the present invention is desalted and copolycondensed with the corresponding (S) -configuration optically active dichlorosilane, the (R) -configuration optically active dichlorosilane, and sodium metal in toluene to obtain the corresponding optically active dichlorosilane. It synthesizes an active polysilane copolymer and is represented by the following general formula (Formula 9). At this time, the winding property of the spiral is determined by the excess of the optically active dichlorosilane of the (R) -configuration and the optically active dichlorosilane of the (S) -configuration used. That is,
If (R) -configured dichlorosilane> (S) -configured dichlorosilane, it has the same winding property as a homopolymer synthesized from only the (R) -configured optically active dichlorosilane. Conversely, if (S) -configuration dichlorosilane> (R) -configuration dichlorosilane, the winding property is the same as that of a homopolymer synthesized from only the (S) -configuration optically active dichlorosilane.

[0025]

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At this time, the dichlorosilanes containing an optically active organic substituent to be used have Na 2
There is no risk of racemization or rearrangement during the desalination condensation reaction, and the degree of steric hindrance between the silicon monomers during the condensation reaction is relatively small, so high-molecular-weight optically active linear organic polysilanes can be easily produced. I do. According to the findings of the present inventors, the effect that a very small amount of the chiral carbon at the β-position fixes the main chain of the entire organic polysilane copolymer having a chain skeleton almost in one direction to a helix having a constant pitch is remarkable. on the other hand,
On the other hand, in the branched structure of the α-position carbon, for example, i-propyl group and cyclohexyl group, the steric requirement is extremely high, and as a result, the absorption width is extremely low, usually 1000 or less, and the main chain absorption maximum is 300 to 320 nm. Only a very wide organic polysilane copolymer was obtained.

[0027]

EXAMPLES Specific examples of the synthesis of the optically active linear organic polysilane copolymer of the present invention will be described more specifically with reference to the following Examples, but the present invention is not limited to these Examples.

Reference Example 1 A specific synthesis example of poly [n-hexyl- (S) -2-methylbutylsilane] _0.05 -co (co)-(n-hexyl-2-methylpropylsilane) _0.95 is shown. After the inside of the reaction vessel was sufficiently dehydrated and degassed and purged with argon gas, 0.98 g of metallic sodium, 0.05 g of 18-crown ether-6 and 50 ml of dehydrated toluene were placed in a flask. N-Hexyl- (S)-at an oil bath temperature of 120 ° C
A mixture of 0.26 g (5 mol%) of 2-methylbutyldichlorosilane and 4.58 g (95 mol%) of n-hexyl-2-methylpropyldichlorosilane was dropped at once,
The reaction was performed for 8 hours. The reaction mixture was filtered under pressure, and ethyl alcohol was added to the filtrate. The resulting white precipitate was collected by a centrifuge and dried in vacuum at 120 ° C. Yield 0.90
g, and the yield was 26% in terms of dichlorosilane. According to the GPC method, the weight average molecular weight is bimodal with 3,000,000 and 80,000, and the former is 48% and the latter is 52% by integration ratio.
Met. FIG. 1 shows an ultraviolet absorption spectrum and a circular dichroic spectrum of the obtained polysilane copolymer. That is, FIG. 1 shows the poly [n-hexyl- (S) obtained in Reference Example 1.
FIG. 2 is a diagram showing an absorption spectrum and a circular dichroic absorption spectrum (in isooctane at −5 ° C.) of _0.05 -co- (n-hexyl-2-methylpropylsilane) _0.95 . In FIG. 1, the horizontal axis represents photon energy (eV), the left vertical axis represents extinction coefficient [ε (Si-unit) ⁻¹ dm ³ cm ⁻¹ ],
The right vertical axis represents the circular two-color absorption coefficient [Δε (Si-unit) ^-1 dm ^3]
cm ^-1 ]. From the comparison of these spectra, 3.
It was found that the cotton CD absorption band at 93 eV was a perfect analog of the main chain absorption band at 3.93 eV, and that the absorption maxima coincided. For comparison, poly [n-hexyl-
FIG. 2 shows an ultraviolet absorption spectrum and a circular dichroic spectrum of (S) -2-methylbutylsilane] homopolymer. That is, FIG. 2 shows poly [n-hexyl- (S)-
[2-Methylbutylsilane] is a diagram showing an absorption spectrum and circular two-color absorption spectrum (in isooctane at -5 ° C). 2, each vertical axis and horizontal axis have the same meaning as in FIG. From the comparison between FIG. 1 and FIG. 2, although a slight difference is recognized between the intensity of the ultraviolet absorption spectrum and the intensity of the circular dichroism spectrum of the homopolymer and the copolymer, the absorption maximum and the half width are almost the same. It has already been shown for homopolymers that the intensity of the spectrum is mainly due to the slightly different molecular weight [M. M. Fujiki, Applied Physics Letters, 65, 3251 (199
4)]. Further, the asymmetry factor (the value obtained by dividing the CD absorption band at 3.93 eV by the ultraviolet absorption band at 3.93 eV), which is very sensitive to the helical property, is 2.3 × 10 ^{-4 for} the homopolymer and 2.3 for the copolymer. ^Was almost the same as 2.0 × 10 ⁻⁴ . This means that the copolymer contains only 5% of (S) -chiral silane and has the same winding, spiral pitch, and rigid polymer structure as the homopolymer. .

Reference Example 2 A specific synthesis example of poly [n-hexyl- (R) -2-methylbutylsilane] _0.05 -co- (n-hexyl-2-methylpropylsilane) _0.95 is shown. After the inside of the reaction vessel was sufficiently dehydrated and degassed and purged with argon gas, 0.98 g of sodium metal and 0.05 g of 18-crown ether-6 were obtained.
And 50 ml of dehydrated toluene were placed in the flask. At an oil bath temperature of 120 ° C., 0.26 g (5 mol%) of n-hexyl- (R) -2-methylbutyldichlorosilane and 4.58 g of n-hexyl-2-methylpropyldichlorosilane
(95 mol%) was dropped at once, and reacted for 8 hours. The reaction mixture was filtered under pressure, and ethyl alcohol was added to the filtrate. The resulting white precipitate is collected by a centrifuge,
Vacuum dried at 120 ° C. The yield was 0.90 g, and the yield was 26% in terms of dichlorosilane. According to the GPC method, the weight average molecular weight was bimodal with 2,000,000 and 60,000, and the integration ratio was 38% for the former and 62% for the latter. FIG. 3 shows an ultraviolet absorption spectrum and a circular dichroic spectrum of the obtained polysilane copolymer. For comparison, FIG. 4 shows an ultraviolet absorption spectrum and a circular dichroic spectrum of poly [n-hexyl- (R) -2-methylbutylsilane] homopolymer. That is, FIG. 3 shows poly [n-hexyl- (R) -2-methylbutylsilane] _0.05 -co- obtained in Reference Example 2.
(N-hexyl-2-methylpropylsilane) Absorption at _0.95 , circular dichroism absorption spectrum (in isooctane, -5 ° C)
FIG. FIG. 4 shows poly [n] as a comparative example.
-Hexyl- (R) -2-methylbutylsilane] absorption spectrum (in isooctane at -5 ° C)
FIG. In each figure, each ordinate and abscissa correspond to FIG.
Is synonymous with From a comparison of these spectra, 3.9
It was revealed that the cotton CD absorption band at 3 eV was completely similar to the main chain absorption band at 3.93 eV, and that the absorption maximum was in agreement. Although the spectral characteristics of the poly [n-hexyl- (R) -2-methylbutylsilane] homopolymer are slightly different in intensity from the ultraviolet absorption spectrum and the circular dichroic spectrum, the absorption maximum and half of the absorption are observed. The price range was almost the same. The asymmetry factor is a homopolymer-
It was almost the same as 2.2 × 10 ^-4 and -1.9 × 10 ^{-4 for the} copolymer. This means that only 5
% Of (R) -chiral silane means that it has the same winding, spiral pitch, and rigid polymer structure as the homopolymer. Naturally, in the case of (R) -chiral silane, the helical winding property is opposite to that of (S) -chiral silane.

Reference Example 3 The same copolymerization experiment was repeated to obtain poly (n-hexyl-2).
The relationship between the content of (S) -2-methylbutylsilane or (R) -2-methylbutylsilane in the (-methylpropylsilane) system and the asymmetry factor was determined. The results are summarized in FIG. That is, FIG. 5 shows poly (n-hexyl-2-
Methylbutylsilane) _x -co- (n-hexyl-2-methylpropylsilane) In the _1-x system, the content of the (S) -form or the (R) -form and the asymmetry factor (-5 ° C in isooctane) FIG. In FIG. 5, the horizontal axis represents the mole fraction (mol%) of each chiral, and the vertical axis represents the asymmetry factor [(Δε / ε) × 10 ⁻⁴ ]. The fact that the asymmetry factor is zero means that the right-handed spiral and the left-handed spiral coexist in the system equally by 50%.
From FIG. 5, if the (S) -chiral compound or (R) -chiral compound is contained even at about 0.5%, it means that the helical winding property of the entire polysilane is almost aligned to one side.

A similar effect is obtained by using poly [methyl- (S) -2
-Methylbutylsilane] _0.05 -co- (n-hexyl-2
-Methylpropylsilane) is also observed at _0.95 . In this case, it can be understood that the n-hexyl group of the achiral monomer plays an important role mainly in maintaining the rigidity of the copolymer. According to the findings of the present inventors, the helical structure of the copolymer is rigidly aligned in one direction even when another alkyl group, an aralkyl group, an aryloxyalkyl group, or an alkyl ether group is used instead of the n-hexyl group. It turns out that you can.

Example 1 A specific example of the synthesis of poly [n-hexyl- (S) -2-methylbutylsilane] _{0.60 -co-} [n-hexyl- (R) -2-methylbutylsilane) _0.40 is shown. After the inside of the reaction vessel was sufficiently dehydrated and degassed and purged with argon gas, 0.98 g of sodium metal and 0.1% of 18-crown ether-6 were added.
05 g and 50 ml of dehydrated toluene were placed in a flask. At an oil bath temperature of 120 ° C., n-hexyl- (S) -2-
3.06 g (60 mol%) of methylbutyldichlorosilane
And a mixture of 2.04 g (40 mol%) of n-hexyl- (R) -2-methylbutyldichlorosilane was dropped at once, and reacted for 8 hours. The reaction mixture was filtered under pressure, and ethyl alcohol was added to the filtrate. The resulting white precipitate was collected by a centrifuge and dried in vacuum at 120 ° C. The yield is 1.
There was 16 g, and the yield was 32% in terms of dichlorosilane. According to the GPC method, the weight average molecular weight was 2.5 million and 7
It is bimodal, with the former at 28% and the latter at 72%
%Met. FIG. 6 shows an ultraviolet absorption spectrum and a circular dichroic spectrum of the obtained polysilane copolymer. That is,
FIG. 6 shows the poly [n-hexyl-
(S) -2-methylbutylsilane] _{0.60 -co-} [n-hexyl- (R) -2-methylbutylsilane) _0.40 absorption, circular dichroism absorption spectrum (in isooctane at -5 ° C)
FIG. 6, each vertical axis and horizontal axis are shown in FIG.
Is synonymous with From a comparison of these spectra, 3.9
It was revealed that the cotton CD absorption band at 3 eV was completely similar to the main chain absorption band at 3.93 eV, and that the absorption maximum was in agreement. The poly [n-hexyl- (S) -2 in FIG.
Compared with the UV absorption spectrum of the homopolymer and the circular dichroic spectrum, although there is a slight difference in the intensity of the UV absorption spectrum and the circular dichroic spectrum of the homopolymer and the copolymer, The absorption maximum and half width were almost the same. The intensity of the spectrum can mainly be explained by the slight difference in molecular weight. The asymmetry factor is 2.2 × 10 ^-4 for the copolymer,
It was exactly the same as that of the homopolymer. This means that the copolymer has the same winding, helical pitch and rigid polymer structure as the homopolymer only by containing an excess of (S) -chiral silane of only 20% in the copolymer. ing.

Example 2 A specific example of the synthesis of poly [n-hexyl- (S) -2-methylbutylsilane] _{0.40 -co-} [n-hexyl- (R) -2-methylbutylsilane) _0.60 is shown. After sufficiently dehydrating and degassing the inside of the reaction vessel and purging with argon gas, 0.99 g of sodium metal and 0.1% of 18-crown ether-6 were added.
05 g and 50 ml of dehydrated toluene were placed in a flask. At an oil bath temperature of 120 ° C., n-hexyl- (S) -2-
2.04 g (40 mol%) of methylbutyldichlorosilane
And a mixture of 3.06 g (60 mol%) of n-hexyl- (R) -2-methylbutyldichlorosilane was dropped at once, and reacted for 8 hours. The reaction mixture was filtered under pressure, and ethyl alcohol was added to the filtrate. The resulting white precipitate was collected by a centrifuge and dried in vacuum at 120 ° C. The yield is 0.
The amount was 58 g, and the yield was 13% in terms of dichlorosilane. According to the GPC method, the weight average molecular weight was 2.5 million and 7
10,000 bimodal, the integration ratio of the former is 45% and the latter is 55%
%Met. FIG. 7 shows an ultraviolet absorption spectrum and a circular dichroic spectrum of the obtained polysilane copolymer. That is,
FIG. 7 shows the poly [n-hexyl-
(S) -2-methylbutylsilane] _{0.40 -co-} [n-hexyl- (R) -2-methylbutylsilane) absorption at _0.60 , circular two-color absorption spectrum (in isooctane at -5 ° C)
FIG. In FIG. 7, each vertical axis and horizontal axis are shown in FIG.
Is synonymous with From a comparison of these spectra, 3.9
It was revealed that the cotton CD absorption band at 3 eV was completely similar to the main chain absorption band at 3.93 eV, and that the absorption maximum was in agreement. The poly [n-hexyl- (R) -2 in FIG.
Compared with the UV absorption spectrum of the homopolymer and the circular dichroic spectrum, although there is a slight difference in the intensity of the UV absorption spectrum and the circular dichroic spectrum of the homopolymer and the copolymer, The absorption maximum and half width were almost the same. The intensity of the spectrum can mainly be explained by the slight difference in molecular weight. The asymmetry factor was as follows: the copolymer was -2.2 × 10
^-4 , which was exactly the same as that of the homopolymer. This means that the copolymer has the same winding, helical pitch and rigid polymer structure as the homopolymer only by containing an excess of (R) -chiral silane of only 20% in the copolymer. ing. Naturally, in the case of (R) -chiral silane, the helical winding property is opposite to that of (S) -chiral silane.

Example 3 The same copolymerization experiment was repeated to obtain poly (n-hexyl-2).
The relationship between the content of (S) -form or (R) -form in the (-methylpropylsilane) system and the asymmetry factor was determined. The results are summarized in FIG. That is, FIG. 8 shows poly [n-hexyl- (S) -2-methylbutylsilane] _x -co- [n
-Hexyl- (R) -2-methylbutylsilane) Diagram showing the relationship between the content of the (S) -form or the (R) -form and the asymmetry factor (in isooctane, -5 ° C) in the _1-x system. It is. In FIG. 8, the vertical axis represents the asymmetry factor [(Δε /
ε) × 10 ⁴ ], the upper abscissa indicates the mole fraction (mol%) of [R] chiral Si units, and the lower abscissa indicates the mole fraction (mol%) of [S] chiral Si units. The fact that the asymmetry factor is zero means that the right-handed spiral and the left-handed spiral coexist in the system equally by 50%. From FIG. 8, (S)
If the chiral form or (R) -chiral form is contained in excess of about 2 to 3%, it means that the helical winding property of the whole polysilane is almost unilaterally aligned.

A similar effect is obtained by using poly [methyl- (S) -2
-Methylbutylsilane] _0.05 -co- [n-hexyl-
(S) -2-methylbutylsilane) was also observed at _0.95 ,
In this case, it can be understood that the n-hexyl group of the achiral monomer plays an important role mainly in maintaining the rigidity of the copolymer. The present inventors have found that, instead of the n-hexyl group, other alkyl groups, aralkyl groups, aryloxyalkyl groups, and alkyl ether groups can be used.
It has been found that the helical structure of the copolymer can be rigid and aligned in one direction.

[0036]

As shown in the present invention, if two kinds of dichlorosilanes having an alkyl group having a branched structure at the β-position are used as raw materials, an optically active chiral monomer having a low optical purity may be used. Achiral monomer containing a very small amount of chiral monomer having a low purity of 10
It has been clarified that the helical structure, main chain absorption and circular dichroic absorption spectrum characteristics almost identical to those of the homopolymer synthesized from 0% chiral monomer are provided. That is, industrially, a very small amount of chiral monomer, or an impure chiral monomer, which can be said to be almost racemic, can be used. Alternatively, it has become possible to provide an organic polysilane having a uniform spiral winding property and a uniform spiral pitch at a very low cost. By selecting the side chain substituent appropriately, a uniform and single helix structure with optical characteristics with significantly higher main chain absorption intensity and extremely narrow absorption width compared to conventional flexible organic polysilanes Is an ideal one-dimensional semiconductor with no interchain interaction and an atomic level limit quantum wire structure that will be realized in the near future. It is extremely useful as a basic model substance and can be used as a polymer standard substance. Such an optically active organic polysilane is expected to be used as a new type of enantiomer recognition material.

[Brief description of the drawings]

FIG. 1 shows the poly [n-hexyl- obtained in Reference Example 1.
(S) -2-Methylbutylsilane] It is a figure which shows the absorption of _0.05 -co- (n-hexyl-2-methylpropylsilane) _0.95 , and a circular dichroism absorption spectrum (in isooctane, -5 degreeC).

FIG. 2 shows a comparison example of poly [n-hexyl- (S)-
[2-Methylbutylsilane] is a diagram showing an absorption spectrum and circular two-color absorption spectrum (in isooctane at -5 ° C).

FIG. 3 shows the poly [n-hexyl- obtained in Reference Example 2.
(R) -2-Methylbutylsilane] It is a figure which shows the absorption of _0.05 -co- (n-hexyl-2-methylpropylsilane) _0.95 , and a circular dichroism absorption spectrum (in isooctane, -5 degreeC).

FIG. 4 shows a comparative example of poly [n-hexyl- (R)-
[2-Methylbutylsilane] is a diagram showing an absorption spectrum and circular two-color absorption spectrum (in isooctane at -5 ° C).

FIG. 5: Content of (S) -form or (R) -form in poly (n-hexyl-2-methylbutylsilane) _x -co- (n-hexyl-2-methylpropylsilane) _1-x system FIG. 4 is a diagram showing the relationship between the asymmetry factor (in isooctane, at −5 ° C.).

FIG. 6 shows the poly [n-hexyl- obtained in Example 1.
(S) -2-methylbutylsilane] _{0.60 -co-} [n-hexyl- (R) -2-methylbutylsilane) _0.40 absorption, circular dichroism absorption spectrum (in isooctane at -5 ° C)
FIG.

FIG. 7: Poly [n-hexyl- obtained in Example 2
(S) -2-methylbutylsilane] _{0.40 -co-} [n-hexyl- (R) -2-methylbutylsilane) absorption at _0.60 , circular two-color absorption spectrum (in isooctane at -5 ° C)
FIG.

FIG. 8 shows a poly [n-hexyl- (S) -2-methylbutylsilane] _x -co- [n-hexyl- (R) -2-methylbutylsilane] _1-x- based (S) -form Alternatively, the content of the (R) -form and the asymmetry factor (in isooctane,
FIG.

Claims (1)

[Claims] 1. A compound represented by the following general formula (1): (Wherein R ₁ and R ₂ are the same or different, an alkyl group, an aralkyl group, an aryloxyalkyl group, or an alkyl ether group, R ^* is the same or different and represents a chiral alkyl group having a branched structure at the β-position. , X is 0.001 ≦
x ≦ 0.999), wherein a silicon unit having an optically active chiral organic substituent introduced therein is included in a part of the main chain skeleton, and the number of n is in the range of 10 to 100,000. Characteristic optically active organosilicon polymer copolymer.