JP2000053771A - Optically active organic silicon polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optically active organic silicon polymer having a struc ture in which organic substituents each containing an asymmetric center are directly bonded to silicon atoms, stably holding a rigid rod-like structure even in a solution at room temperature, reversibly causing the change between dextrorotatory and levorotatory in response to the change of temperature, and useful as an optically active material for switch.memories, etc. SOLUTION: An optically active organic silicon polymer of the formula [R* is a chiral alkyl having an asymmetric center at the γ-position; R is an aralkyl; (n) is 10-100,000]. The silicon polymer is the homopolymer of silane monomer units each having both an aralkyl group and an S or R-configurated chiral alkyl group having a branched structure at the γ-position. A chlorosilane having two Si-Cl bonds and containing a symmetric substitution type or asymmetric substitution type optically active group can be subjected to a desalting condensation reaction with metal sodium in toluene to synthesize the corresponding optically active organic polysilane homopolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel spinning phenomenon in which the polysilane main chain undergoes a reversible right-helical / left-helical structural change with temperature and a reversible right-hand / left-rotational change. It relates to an optically active organosilicon polymer.

[0002]

2. Description of the Related Art Many organic silicon compounds are industrially useful, and are used, for example, as surface treatment agents, water-repellent agents, oil-repellent agents, electric insulators, heat media, and precursors for ceramic materials. Are organic polymers containing silicon as part of the skeleton.

[0003] In recent years, solvent-soluble organic polysilanes whose main chain skeleton is composed of only silicon have been attracting attention as a new type of functional material.
Numerous studies directed at optical waveguide materials have been made.
Organic polysilanes generally have Si around 300 to 400 nm.
-Has an ultraviolet absorption band based on a main chain skeleton unique to the Si chain. Conventional polysilane has a main chain absorption of about 5,000 to 10,000 (monomer unit / liter) in a solution at room temperature because the main chain skeleton has a random coil shape.
^-1 cm ^-1 , half width 0.5 to 0.6 eV (about 40 to 60 n
m) a broad backbone absorption of the order of m). On the other hand, a series of recently reported organopolysilanes having an alkyl group having a branched structure at the β-position have a molecular absorption coefficient of about 40,000 to 110,00 due to the rigid rod shape of the main chain skeleton.
0 (monomer unit / liter) ^-1 cm ^-1 , half width 0.1
It shows very steep main chain absorption of about 0.05 eV (about 8 to 4 nm). This is described, for example, in (1) M. Fujiki, Journal of American Chemical Society (J. Am. Chem. Soc.), Vol. 116, No. 601
7 (1994), (2) M.P. Fujiki's Journal of American Chemical Society (J.
Am. Chem. Soc.), 116, 11976 (19
1994), (3) M.P. Applied Physics Letters by Fujiki (Appl. Phys. Lett.), Volume 65,
P.3251 (1994), (4) M.P. Fujiki, Journal of American Chemical Society (J. Am. Chem. Soc.), Vol. 118, No. 7424
Page (1996). That is, it has become known that the absorption spectrum intensity and the half-value width of the organic polysilane vary significantly depending on the form of the main chain.

[0004] Since organic polysilane is a polymer whose main chain is composed of only silicon, the main chain is relatively easily decomposed by irradiation with ultraviolet rays, and the molecular weight is reduced or siloxane conversion proceeds. Application examples of photoresist utilizing this property have been reported. However, as described above, since organic polysilanes cause main chain decomposition relatively easily, organic polysilanes are used as light-related functional materials, such as non-linear optical materials and light-emitting materials that directly use the main chain absorption and emission phenomena of organic polysilanes. It is unsuitable for use in terms of life. However, since organic polysilane itself is very stable in a dark place, if it is possible to find a property that functions at a longer wavelength side than the main-chain absorption band of organic polysilane, it is possible to overcome the disadvantage that this lifetime is short. .

By the way, carbons whose main chain has one-way helicity, such as poly (triphenylmethyl methacrylate) and poly (diphenylpyridylmethyl methacrylate), which have been synthesized using a polymerization initiator of spantin-n-butyllithium. A skeletal polymer is known as a polymer material that recognizes an enantiomer. This is for example the case in Y. Journal of American Chemical Society, by Y. Okamoto, et al.
(J. Am. Chem. Soc.), 103, 6971 (1
981). Organic polymers whose main chain has one-way helicity are marketed as column materials for high-performance liquid chromatography for separating and separating enantiomers, supported on silica gel surfaces [Daicel Chemical Co., Ltd. Chiralpak-OT, Chiralpak -OP]. However, the poly (triphenylmethyl methacrylate) -based material has a disadvantage that when the side chain fixing the main chain helical structure is eliminated by hydrolysis or solvolysis, the ability to recognize enantiomers is also lost. On the other hand, the silicon backbone skeleton and hydrocarbon side chains of organic polysilanes are resistant to hydrolysis and solvolysis. It can be used as a column material for liquid chromatography (hereinafter sometimes abbreviated as “HPLC”) and gas chromatography (hereinafter sometimes abbreviated as “GC”).
At present, column materials for enantiomer recognition (hereinafter referred to as "C
Most of them are sometimes 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. If a totally artificial optically active organic polysilane having an optically active substituent can be supported on a carrier, a CSP for HPLC or GC
The use as a CSP for use can be further opened. What is important here is that once the carbon skeleton polymer having a one-way helicity in the main chain is supported on the silica gel surface, the spiral winding property is invariable, so that the elution order of the enantiomer does not usually change. If changing the column temperature can cause a reversible change from the right helical structure to the left helical structure or vice versa from the left helical structure to the right helical structure, elution of the enantiomer can be achieved simply by changing the column temperature. It is possible to reverse the order. One or two cases where the order of elution of the enantiomers is reversed by a change in the polarity of the elution solvent are known, but no examples where the order of elution of the enantiomers is reversed only with the column temperature are currently unknown.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an optically active switch which reversibly changes dextrorotatory to levorotatory changes with temperature. It is to provide a material for memory as well as a new material for recognizing an enantiomer, particularly as an enantiomer recognizing material for HPLC or GC, having a structure in which an organic substituent containing an asymmetric center is directly bonded to a silicon atom, An object of the present invention is to provide an optically active organic silicon polymer in which a rigid rod-like structure is stably maintained even at room temperature.

[0007]

The optically active organosilicon polymer of the present invention has the following general formula (1):

[0008]

Embedded image

[In the formula, R ^* represents a chiral alkyl group having a chiral center at the γ-position, R represents an aralkyl group, and n is an integer in the range of 10 to 100,000.]
It is characterized by being represented by

Here, R ^* in the general formula (1) is (S)-
Represents a 3,7-dimethyloctyl group, R represents a γ-phenylpropyl group, and n can be an integer ranging from 10 to 100,000.

In the general formula (1), R ^* is (R)-
Represents a 3,7-dimethyloctyl group, R represents a γ-phenylpropyl group, and n can be an integer ranging from 10 to 100,000.

The optically active organosilicon polymer of the present invention comprises:
It is a homopolymer of a silane monomer unit having both a chiral alkyl group and an aralkyl group having a (S) configuration or a (R) configuration having a branched structure at the γ-position.

The chlorosilanes containing a symmetrically substituted or asymmetrically substituted optically active group having two Si—C1 bonds used in the synthesis of the optically active organosilicon polymer of the present invention are represented by the following reaction formula (i): It is generally synthesized based on (ii) and (iii). For specific synthesis methods and analysis results, see Japanese Patent Application Nos. 5-202474 and 5-20.
No. 2528, each of which is disclosed.

[0014]

Embedded image (i) R ^* -X + Mg → R ^* MgX (X = Cl, Br) Et ₂ O (ii) RX—Mg → RMgX (X = Cl, Br) Et ₂ O (iii) RSiCl ₃ + R ^* MgX → R ^* RSiCl ₂ Et ₂ O where Et ₂ O represents diethyl ether.

The ¹³ C-NMR, ²⁹ Si-NMR (CDCl ₃ , 3
0 ° C.), boiling point, and specific rotation (neat liquid, 24 ° C.) are summarized below.

1) (S) -3,7-dimethyloctyl-
γ-phenylpropylsilane dichloride ¹³ C-NMR: 17.507, 19.090, 20.220, 20.377, 22.4
73, 22.616, 22.703,24.725, 27.539, 27.961, 29.126,
34.783, 36.462, 39.297, 41.802 ppm ²⁹ Si-NMR: 34.101 ppm Boiling point 162 ° C./0.70 mmHg [α] _D 1.56 ° 2) ¹³ C-NMR: 17.507, 19.090, 20.220, 20.377,
22.473, 22.616,22.703, 24.725, 27.539, 27.961, 29.
126, 34.783, 36.462, 39.297, 41.802 ppm ²⁹ Si-NMR: 34.101 ppm Boiling point 162 ° C / 0.70 mmHg [α] _D -1.56 °

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The optically active polysilane of the present invention comprises
By desalting and condensing the optically active organic dichlorosilane with sodium metal in toluene, a corresponding optically active organic polysilane homopolymer can be synthesized, and is specifically represented by the following formula (2).

[0018]

Embedded image

[0019]

EXAMPLES The method for synthesizing the optically active linear organic polysilane 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.

(Example 1) Poly [((R)-
3,7-dimethyloctyl) -γ-phenylpropylsilane].

After sufficiently dehydrating and degassing the inside of the reaction vessel and purging with argon gas, 0.78 g of metallic sodium, 0.0
9 g of 18-crown ether-6 and 15 ml of dehydrated toluene were placed in a flask. The oil bath temperature was maintained at 120 ° C., and 3.6 g of (R) -3,7-dimethyloctyl) -γ-phenylpropylsilanedichloride was added dropwise and reacted for 8 hours. The reaction mixture solution was filtered under pressure, and fractionally reprecipitated using ethyl alcohol to obtain a white precipitate. The obtained white precipitate was collected by a centrifugal separator, and then dried in vacuum at 120 ° C. for 6 hours to obtain poly (((R)).
-3,7-dimethyloctyl) -γ-phenylpropylsilane]. The yield was 1.3 g. According to the GPC method, the obtained organic polysilane had a weight average molecular weight of the first component of 2.24 million and a weight average molecular weight of the second component of 4
The weight average molecular weight of the third and third components was 10,000. FIG.
In addition, poly [((R) -3,7-dimethyloctyl) -γ
-Phenylpropylsilane] (a component having a weight average molecular weight of 40,000) in isooctane at -84 ° C and 80 ° C.
The ultraviolet extinction coefficient (UV spectrum) and the circular two-color extinction coefficient (CD spectrum) are shown for each of ° C. FIG.
The data at -84 ° C (temperature drop process) is represented by a solid line,
The data in ° C. is represented by a dashed line.

In FIG. 1, the horizontal axis is the photon energy (e
V), the left vertical axis is the ultraviolet absorption coefficient (UV spectrum) [ε
(Si-unit) ^-1 dm ³ cm ^-1 ], and the right vertical axis represents circular dichroism absorption coefficient (CD spectrum) [Δε (Si-unit) ^-1 dm].
³ cm ^-1 ]. The upper two graphs in FIG. 1 read the data on the right vertical axis and show the CD spectrum, and the lower two graphs read the data on the left vertical axis and show the UV spectrum. From the graph of the UV spectrum and the CD spectrum, it can be seen that the negative cotton CD absorption band at 3.9 eV at −84 ° C. is a completely similar shape of the main chain absorption band at 3.9 eV, and that the absorption maximum coincides. On the other hand, at 80 ° C., 3.8 e
With respect to the main chain absorption band at V, the circular two-color absorption band is 3.8 eV.
Cotton CD Absorption Band of 4.0eV and Negative Cotton CD of 4.0eV
Divided into absorption bands. ε value of 4500 at -84 ° C
Since the 0 and ε values are 20,000 at 80 ° C., it is shown that the polysilane main chain skeleton maintains a rigid rod-like structure in this temperature range. From FIG. 1, on the longer wavelength side than the absorption of the main chain, it becomes levorotatory at −84 ° C. and dextrorotatory at 80 ° C. with respect to linearly polarized light incidence. That is, the optical rotation sign is-
It is completely reversed between 84 ° C. and 80 ° C., and it can be seen that inversion of the spiral winding property occurs within this temperature.

FIG. 2 shows a graph of poly [((R) -3,7-dimethyloctyl) with the vertical axis representing the asymmetry factor (Δε / ε) as an index of the helical purity and the horizontal axis representing the measurement temperature (° C.). −
[γ-Phenylpropylsilane] were plotted on the measured values in the temperature decreasing process and the temperature increasing process. Here, the asymmetry factor is a value in isooctane. As a result, the right helical structure and the left helical structure change, and the sign of the cotton CD absorption band is a negative cotton signal at a temperature lower than 35 ° C. below 35 ° C., and a positive and negative splitting cotton signal at a temperature higher than 35 ° C. Give a signal. That is, it is understood that the inversion of the spiral winding partially occurs at 35 ° C. Regarding the spiral inversion behavior, there is no change between the heating process and the cooling process. Although the relationship between the spiral winding property of polysilane and the sign of the cotton CD absorption band is unclear, here, for convenience, if the spiral winding property of polysilane that gives a positive cotton CD absorption band is described as (+)-helix structure , 35 ° C or lower, the (-)-helix structure is predominant, and above 35 ° C, the (+)-helix structure and the (-)-helix structure coexist.

Example 2 Poly [((S) -3,7-dimethyloctyl) -γ-phenylpropylsilane] was synthesized according to Example 1. Poly [((S) -3,7-dimethyloctyl) -γ-phenylpropylsilane]
As in the case of poly [((R) -3,7-dimethyloctyl) -γ-phenylpropylsilane], helix inversion partially occurred in the main chain at 35 ° C. or higher. The sign of the cotton CD absorption band was opposite to that of poly [((R) -3,7-dimethyloctyl) -γ-phenylpropylsilane].

[0025]

As described above in detail, the organic polysilanes of the present invention accompanied by a change in the positive cotton CD signal / negative cotton CD signal are dextrorotatory on the longer wavelength side than the decomposition wavelength of the polysilane main chain. Since it is expected to show a memory switching phenomenon using a change in sex, there is a possibility as a new type of functional element material that has overcome the disadvantage of main chain decomposition. Because the circular dichroism and the optical rotatory dispersion are linked to each other by the Kramers-Kronig relationship, if the temperature change of the optical rotation related to the helix structure of this organopolysilane was detected at a longer wavelength than the main-chain absorption band. In this case, the optical rotation can be expected to change positively or negatively at the (+)-helix ⇔ (-)-helix transition temperature. The organic polysilane of the present invention has a relatively weak optical rotation having an absorbance of about 1 and an optical rotation of about ten to several millimeters to several millidegrees, but a high concentration polysilane solution having an absorbance of about 100 or a long optical path length. It is relatively easy to achieve an optical rotation of several degrees. Utilizing this property, a halogenated solvent having a very low transmission loss in the near-infrared optical communication wavelength band that is much longer than the main chain absorption band of the organic polysilane, for example, 0.78 to 1.55 μm, for example, heavy dichloromethane, chloroform-use heavy chlorobenzene, perfluorobenzene and the like, the temperature-induced memory switch element m _sec to mu _sec order to determine from such half-width of ²⁹ Si-NMR can be expected.

From the viewpoint of an enantiomer-recognizing polymer material, a completely artificial optically active organic polysilane having an optically active substituent having a unidirectional helical structure is
Utilizing the feature that the silicon main chain skeleton and hydrocarbon side chains have sufficient resistance to hydrolysis and solvolysis, it is used as a HPLC or GC column material in dark places and under deoxygenation conditions. Useful. In particular, for polysilanes in which the helical winding property of the main chain is inverted due to a temperature change, the winding property of the side chain that is the enantiomer recognition site is also inverted.Therefore, it is possible to reverse the elution order of the enantiomer by changing the column temperature. it can. The polysilane of the present invention, which exhibits a (+)-helix ⇔ (-)-helix transition only by changing the column temperature, has potential as a new functional HPLC or GC column material for temperature switching.

[Brief description of the drawings]

FIG. 1: Poly [((R) -3,7-dimethyloctyl)
[Γ-Phenylpropylsilane]] is a diagram showing an ultraviolet absorption spectrum (UV spectrum) and a circular dichroism absorption spectrum (CD spectrum).

FIG. 2 shows poly [((R) -3,7-dimethyloctyl)
[Γ-phenylpropylsilane] and a measurement temperature.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiromi Takigawa 1-3-1 Gotenyama, Musashino-shi, Tokyo NTT Advanced Technology Co., Ltd. F-term (reference) 4J035 JA01 JB02 JB03 JB10 LA03 LB20

Claims (3)

[Claims] [Claim 1] The following general formula (1) Wherein R ^* represents a chiral alkyl group having a chiral center at the γ-position, R represents an aralkyl group, and n represents 10 to 10
An optically active organosilicon polymer, which is an integer in the range of up to 000]. 2. The method according to claim 1, wherein R ^* in the general formula (1) represents a (S) -3,7-dimethyloctyl group.
Represents a γ-phenylpropyl group, and n represents 10 to 10
2. The optically active organosilicon polymer according to claim 1, wherein the integer is in the range of up to 000. 3. The method of claim 1, wherein R ^* in the general formula (1) represents a (R) -3,7-dimethyloctyl group,
Represents a γ-phenylpropyl group, and n represents 10 to 10
2. The optically active organosilicon polymer according to claim 1, wherein the integer is in the range of up to 000.