JP2006293292A - Optical storage medium making use of oligothiophene - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly efficient two-stage-excited hologram memory or other optical storage medium making use of a compound, such as an oligothiophene compound, that although being high in the efficiency of generation of singlet excited state and triplet excited state, is not apt to immediately induce a chemical reaction involving a structural change, etc. <P>SOLUTION: There is provided an optical storage medium of organic mixture comprises a two-stage-excited energy donor capable of being excited to a singlet excited state by irradiation with a first exciting light, subsequently being transferred to the lowest triplet excited state by intersystem crossing and thereafter being excited to a higher triplet excited state by irradiation with a second exciting light and an energy acceptor capable of receiving energy from the energy donor and feeding the energy to a chemical reaction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical storage medium comprising a two-stage excited type energy donor via a highly excited triplet state and an organic mixture having an energy acceptor that receives energy from the energy donor.

  As a hologram memory, a one-step excitation type hologram memory, that is, the object light and the reference light loaded with data on the optical storage medium are simultaneously irradiated to form interference fringes of these two lights, and the intensity distribution of the interference fringes Is stored as data, and then a diffracted light is generated by irradiating the optical memory medium with a reference light, and data is reproduced from the diffracted light.

  When the optical storage medium such as the hologram memory has a layer structure, the recording layer is usually a single layer, and there is a limit to meet the recent demand for large capacity. One effective method for overcoming this limit is to stack a plurality of recording layers.

  However, in the case of using a laminate in which a plurality of recording layers are laminated, it is difficult to realize in the case of the one-step excitation type. That is, when data is recorded on a plurality of recording layers, first, as shown in FIG. 7A, a certain storage layer a1 is irradiated with reference light and object light to store data. Subsequently, as shown in FIG. 7B, the other storage layer a2 is irradiated with reference light and object light to record other data. At this time, as shown in FIGS. 7A and 7B, the object light passes through not only the layer a2 but also other layers including the layer a1. At this time, there arises a problem that data in the layer in which data such as the layer a1 is stored is erased. Further, the same applies to the reproduction of data, and as shown in FIG. 7C, when data of one layer is reproduced, there arises a problem that the reproduction light erases the data of the other layer.

  As a promising technique for solving this problem, there is a method of applying a two-stage excitation type optical storage medium via a highly excited triplet state as shown in FIG. In the example of the hologram memory, as shown in FIG. 8A, when the first excitation light (= gate light) is irradiated, only the layer becomes the lowest triplet excited state and can be recorded. By irradiating the second excitation light (= reference light + object light), it becomes a highly excited triplet excited state, and interference fringes due to two-beam interference are fixed in the medium as a structural change refractive index change. Optical storage is performed. On the other hand, as shown in FIG. 8B, since the layer not irradiated with the first excitation light is not in the lowest triplet excitation state and is not in a memorizable state, the second excitation light (= reference light + Irradiation of (object light) does not result in a triplet excited state, so that two-beam interference does not occur and optical storage is not performed. For this reason, even if there is already stored data, the layer not irradiated with the first excitation light is not erased.

  That is, in the two-stage excitation type, it is necessary to irradiate both the first excitation light and the second excitation light for optical recording. As shown in FIG. The energy donor becomes higher only by exciting the lowest triplet excited state that can be recorded, and then irradiating the object light on which data is placed and the reference light that interferes with the object light and generates interference fringes. A triplet excited state can be obtained, and optical recording becomes possible.

  On the other hand, even if only the object light and the reference light are irradiated without irradiating the gate light, the energy donor cannot be excited to the recordable triplet excited state as shown in FIG. 8B. Optical recording is impossible, and data is not erased in the layer not irradiated with the gate light.

  Biacetyl (butane-2,3-dione, see Non-Patent Document 1) and carbazole (9H-carbazole, non-patent) are used as an organic material that constitutes a two-stage excitation type hologram memory that passes through such a highly excited triplet state. Document 2) is known.

In the methods described in Non-Patent Documents 1 and 2, when biacetyl or carbazole is excited to a highly excited triplet excited state (T _n ), a structural change occurs, and as a result, object light and reference light It is described that the interference fringes formed by the above are fixed as a change in the refractive index in the medium, and recording / reproducing of the hologram is possible.

  However, since these biacetyls and carbazoles themselves have low efficiency, the diffraction efficiency of the reference beam, which is an index indicating the hologram storage / reproduction efficiency, is low, and in order to obtain a diffraction efficiency of 1%, at least about 200 μm. Thickness is required. For this reason, as long as biacetyl or carbazole is used, it is difficult to realize a thin film type optical storage medium having a practical thickness of several μm.

  By the way, as a method for improving the diffraction efficiency, there are a method of increasing the intensity of the light source and a method of increasing the light density by shortening the focal length of the condenser lens. However, according to these methods, the above-described biacetyl and carbazole have a problem that the necessary irradiation intensity of gate light becomes too high and optical damage occurs.

  In contrast, oligothiophene compounds (see Non-Patent Document 3) are known as organic materials that generate highly excited triplet states.

Opt. Lett. , 7, 177 (1982) (Chr. Brauchle et al). Opt. Lett. 6,159 (1981) (GC Bjorklund et al). J. et al. Phys. Chem. , 100, 18683 (1996) (RS Becker et al).

However, when an oligothiophene-based compound is used, even if excited to a highly excited triplet excited state (T _n ), it cannot be expected to cause a chemical reaction such as a structural change immediately from that state. Can't do it.

  That is, as described in Non-Patent Document 3, oligothiophene compounds are conventionally predicted to have high generation efficiency in singlet excited states and triplet excited states by theory, but immediately undergo structural changes. Such chemical reactions are unlikely to occur and cannot be applied to an optical storage medium such as a hologram memory by itself.

  Therefore, the present invention provides a high-efficiency two-step excitation type using a compound such as an oligothiophene compound that has a high generation efficiency of a singlet excited state or a triplet excited state, but does not readily cause a chemical reaction such as a structural change. It is an object of the present invention to provide an optical storage medium including the hologram memory.

  In this invention, it is excited to the singlet excited state by the first excitation light irradiation, and then transitions to the lowest triplet excited state by the intersystem crossing, and then the higher triplet excitation by the second excitation light irradiation. An optical memory comprising an organic mixture comprising: a two-stage excited energy donor excited to a state; and an energy acceptor receiving energy from the energy donor and donating such energy to a chemical reaction By using a medium, the above problem has been solved.

  Since this invention uses a specific energy donor and energy acceptor, energy is transferred from the energy donor excited to the triplet excited state to the energy acceptor, and the passed energy is donated to the chemical reaction. Can do. Accordingly, energy can be appropriately supplied to the chemical reaction, optical recording can be performed more reliably, and an optical storage medium such as a highly efficient two-stage excitation type hologram memory can be provided.

  In addition, when an oligothiophene compound is used as an energy donor, this compound has a high generation efficiency of a singlet excited state or a triplet excited state, so that when a hologram memory is produced using this compound, high diffraction efficiency is obtained. Thus, the memory medium can be made into a practical thin film of several μm.

  Furthermore, the application of the present invention is not limited to the hologram memory, but is a normal refractive index that does not correspond to the interference fringes at any spot (= dot) inside the medium through the process of two-step excitation by light irradiation. The present invention can also be applied to a case where the change is caused with low power. In this case, it can be realized by two beams of the first excitation light and the second excitation light. For example, it is possible to cause a refractive index change at an arbitrary spot where two beams overlap in a three-dimensional medium.

  Hereinafter, the optical storage medium of the present invention will be described in detail with a focus on application to a hologram memory. The invention relating to this optical storage medium is an optical storage medium using a predetermined energy donor and energy acceptor.

  The energy donor refers to a compound such as an oligothiophene compound that has high generation efficiency of a singlet excited state and a triplet excited state, but hardly undergoes a chemical reaction such as a structural change immediately. The compound having high generation efficiency of the singlet excited state or triplet excited state is high in the efficiency of being excited to the singlet excited state by irradiation with the first excitation light, and between the terms to the lowest triplet excited state. It refers to a two-stage excitation type compound that has a high efficiency for crossing and also has a high efficiency of being excited to a higher triplet excited state by irradiation with second excitation light.

  The energy acceptor refers to a compound that receives energy from the energy donor and is in a lowest triplet excited state and can easily donate energy to a chemical reaction. That is, since the energy level of the triplet excited state of the energy acceptor is similar to or slightly smaller than the energy level of the triplet excited state of the energy donor, the energy acceptor of the energy acceptor is easy. A compound that can donate most of the obtained energy to the chemical reaction is preferable.

An example of the energy acceptance relationship between the energy donor and the energy acceptor can be shown in FIG. First, by giving first excitation light which is gate light to an energy donor, the energy donor changes from a ground state (S ₀ ) to a singlet excited state (S ₁ ) or the like. Next, transition to the lowest triplet excited state (T ₁ ) occurs at the intersystem crossing. Then, by applying the second excitation light (in the case of a hologram, object light and reference light), a higher triplet excitation state (T _n ) is obtained.

Next, energy is transferred (ET) from the energy donor in the triplet excited state (T _n ) to the energy acceptor. This returns the energy donor to the ground state (S ₀ ), while the energy acceptor is in the lowest triplet excited state (T ₁ ) and the like. The energy acceptor then donates the obtained energy to the chemical reaction and returns to the ground state (S ₀ ) or changes into a reaction product.

  In the case of using the energy donor and the energy acceptor as described above, a structural change (= refractive index change) occurs due to a chemical reaction by energy obtained by the energy acceptor, and as a result, optical recording is performed.

  Next, the energy donor and energy acceptor constituting the optical storage medium will be described. The energy donor and energy acceptor are not particularly limited as long as they can exhibit the above functions. However, among them, there are preferable energy donors and energy acceptors, and examples thereof will be described here.

  Examples of the preferable energy donor include oligothiophene compounds represented by any of the following formulas (1-1) to (1-4).

In the formulas (1-1) to (1-4), X _{1 to} X ₆ , X _{7a to} X _7b , X _{8a to} X _8d , and X _{9a to} X _9f are _ones of a hydrogen atom, an alkyl group, and an alkyl group. And a group in which a carbon atom in a part is replaced with a silicon atom, a halogen, a hydroxyl group, an alkyloxy group, an aryloxy group, a dialkylamino group, and the like. The _{above, X 1 ~X 6, X 7a} ~X 7b, X 8a ~X 8d, X 9a
˜X _9f may be the same or different.

Among these, oligothiophene compounds as shown in the following formula (2) are more preferable. The compound represented by the formula (2) is a compound represented by the formula (1-3) or the formula (1-4), and X ₂ = X ₃ = X ₄ = X ₅ = X _8a = X _8b = X _8c = X _8d = X _9a = X _9b = X _9c = X _9d = X _9e = X _9f = hydrogen atom, X ₁ represents Si (R ₁ ) (R ₂ ) (R ₃ ), X ₆ Represents Si (R ₄ ) (R ₅ ) (R ₆ ). R _{1 to} R ₆ represent a group selected from a hydrogen atom, an alkyl group, a halogen, a hydroxyl group, an alkyloxy group, an aryloxy group, and a dialkylamino group. Further, R _{1 to} R ₆ may be the same or different. Furthermore, n represents 4 or 5.

  Specific examples of the oligothiophene compound represented by the formula (2) include compounds represented by the following formulas (2-1) to (2-5).

Furthermore, in also the type oligothiophene compound represented by _(2), R 1 ~R ₆ is _an alkyl group having 1 to 2 carbon atoms, an alkyl group having 6 to 10 carbon atoms, an aryl group, an alkenyl group, an alkynyl A compound exhibiting a group, an alkoxy group, a pyridyl group, or a thiophene ring is preferable because it has a more remarkable function as the energy donor, and particularly for each of R _{1 to} R ₃ and R _{4 to} R ₆ , at least A compound in which one of them represents an alkyl group having 6 to 10 carbon atoms, an aryl group, an alkenyl group, an alkynyl group, an alkoxy group, a pyridyl group, or a thiophene ring is more preferable. Specific examples thereof include compounds represented by the above formulas (2-2) to (2-5).

  The knowledge that introduction of an alkyl group via a silicon atom contributes to solubility is described in, for example, J. Org. Mater. Chem. 10, 1471-1507, (2000). However, in the case of oligothiophene having a limited conjugated molecular length, the effect is further manifested.

  That is, when pentathiophene is substituted with an n-decyl group at both ends of the molecule (a compound represented by the following formula (2-5) ′) and when a decyldimethylsilyl group is substituted (the above formula (2- In the compound (5), the latter can dissolve 3 to 4 orders of magnitude more than the former in the same solvent.

  Specifically, the compound represented by the following formula (2-5) ′ has a solubility in chloroform of less than 0.05 mg / ml, a solubility in toluene of less than 0.05 mg / ml, and non-hexane. The solubility of the compound represented by the above formula (2-5) in chloroform is 200 mg / ml or more, the solubility in toluene is 300 mg / ml or more, and the solubility in hexane is 100 mg / ml. The above is shown.

  Further, when the trioctylsilyl group is substituted, oligothiophene can be liquefied even at a temperature close to room temperature, and an amorphous medium having a concentration of 100% can be formed. Such a compound can be used, for example, as an optical recording medium or a non-linear optical medium by being enclosed in a hollow capillary container.

  Thus, substitution of the alkylsilyl group not only allows the substituted compound to be dispersed in the matrix at a high concentration, but also selectively allows other low molecular weight compounds to be close to the oligothiophene site. An inclusive molecular interaction to be deployed can be expressed. As will be described later, the inclusive interaction between the 5,5 ″ ″-bis (decyldimethylsilyl) pentathiophene represented by the formula (2-5) and the azide compound represented by the formula (3-2) Thus, the proximity arrangement is possible, and high-efficiency optical writing that cannot be obtained by other combinations can be realized.

The oligothiophene compound has a singlet excited state (S ₁ ) and a triplet excited state (T _n ) production rate of usually one digit or more compared to biacetyl, which is conventionally known as a compound that is excited in two steps. Preferably it is 2 digits or more, more preferably 3 digits or more. Among these, the compounds represented by the general formulas (1-1) to (1-4) have a production rate several thousand times higher than that of biacetyl, and are particularly preferably used as the energy donor of the present invention.

  Next, examples of the preferable energy acceptor include azide compounds represented by the following formula (3).

  In formula (3), Y represents a group having at least one group selected from an alkyl group, a halogen, an azide group, a sulfonyl group, an aryl group, a hydroxyl group and an alkoxy group, or a hydrogen atom.

Specific examples of such azide compounds include azide compounds represented by the following formula (3-1) or (3-2).

  When the azide-based compound is in a triplet excited state, the reaction shown in the following reaction formula <1> is generated to generate triplet nitrene and nitrogen molecules. The triplet nitrene then undergoes a chemical reaction such as a coupling reaction, an addition reaction to a double bond, or a hydrogen abstraction reaction. For this reason, when an energy acceptor made of the azide compound is used, triplet nitrene causes a structural change in the polymer compound that disperses the energy donor and the energy acceptor in the portion irradiated with light. It is possible to cause a change in refractive index.

When calculated using density functional theory, the excitation energy of S ₀ -T _n of the oligothiophene compound is 3.65 eV (when 340 nm, n = 2), 3.05 eV (407 nm, n = 3). On the other hand, the excitation energy of S ₀ -T ₁ of the azide compound is 3.64 eV (340 nm, for compound (3-1)), 3.47 eV (357 nm, compound (3-2) ). Although there are some high and low numerical values, these compounds can be used in combination as an energy donor and an energy acceptor.

  By the way, it is important that the optical storage medium is uniform and excellent in flatness. For example, in a hologram experiment, when the medium surface is not flat or striae are generated inside the medium, the beam of the object beam and the reference beam is difficult to overlap, and this two-beam interference occurs. This is because it is difficult to fix the interference fringes generated by this as a change in refractive index in the medium. Therefore, as shown in FIG. 2, a method for uniformly and flatly manufacturing an optical storage medium by combining a blade coating method and a thermocompression bonding method will be described.

  First, the above-mentioned energy donor and energy acceptor are mixed and dispersed at a predetermined ratio to obtain an optical storage medium solution. Next, as shown in FIG. 2A, an optical storage medium solution is dropped on the substrate. Then, as shown in FIG. 2 (b), a sweep process is performed to sweep the substrate by a blade (blade) that keeps the distance from the substrate constant, thereby flattening the optical storage medium solution (FIG. 2B). 2 (c)). Next, after such sweeping, the solvent is removed by heating (FIG. 2D), and then the obtained medium is peeled from the substrate (FIG. 2E). Next, a heating process is performed in which the obtained medium is sandwiched between two substrates and heated under pressure (FIG. 2 (f)). Thereafter, the medium is peeled from the substrate (FIG. 2G), whereby a thin film type optical storage medium with improved flatness can be manufactured. When the obtained optical storage medium is thin, a plurality of sheets, such as two, are stacked and thermally compressed in the same manner as in the method of FIG. 2 (f) to obtain a thick optical storage medium (FIG. 2 (h) )). Note that after the step of FIG. 2C, the step of FIG. 2F may be performed by placing the substrate on the medium without performing the steps of FIGS. 2D and 2E.

  In addition to the blade coating method described above, a coating method such as a spin coating method, a spray method, a wire bar method, or an IJ method can be used as a method for applying the optical storage medium solution to the substrate.

  Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1 (Production of oligothiophene compound)
[Production of compound represented by formula (2-1)]
Compound represented by formula (2-1) (5,5 ″ ″-bis (t-butyldimethylsilyl) -2,2 ′: 5 ′, 2 ″: 5 ″, 2 ′ ″: 5 ″ ', 2''''-kinkathiophene) production method and compound data are shown.

[1] Preparation of 2-tributylstannyl-5- (t-butyldimethylsilyl) thiophene Under argon atmosphere, 0.74 g (8.8 mmol) of thiophene (manufactured by Aldrich) was dissolved in 18 ml of tetrahydrofuran, and the temperature was adjusted to -30 ° C. To the kept solution, 5.8 ml (8.8 mmol, hexane solution) of butyl lithium (manufactured by Aldrich) was added dropwise. After stirring this mixed solution at the same temperature for 2 hours, 1.4 g (9.1 mmol) of t-butylchlorodimethylsilane (manufactured by Aldrich) was added, and the mixture was further stirred at the same temperature for 1 hour. To this mixed solution, 6.0 ml (9.1 mmol, hexane solution) of butyllithium was added dropwise and stirred at the same temperature for 2 hours. Then, 2.8 g (8.8 mmol) of chlorotributyltin (Aldrich) was added, and Stir at the same temperature for 1 hour. The mixed solution was stirred at room temperature overnight, diluted with diethyl ether, and poured into a vigorously stirred ice-cold saturated brine. The organic layer was washed with saturated brine, dried over anhydrous sodium sulfate, and then concentrated under reduced pressure to obtain 5.1 g of a crude product.
This crude product was subjected to Kugelrohr distillation at 170 ° C. and 0.3 Torr to obtain 2.6 g of 2-tributylstannyl-5- (t-butyldimethylsilyl) thiophene. The yield was 60%.

[2] Production of compound represented by formula (2-1) To 4 ml of toluene, 0.59 g (0.80 mmol) of 2-tributylstannyl-5- (t-butyldimethylsilyl) thiophene and 5,5 "-Dibromo-2,2 ': 5', 2" -terthiophene (Aldrich) 0.16 g (0.4 mmol) and tetrakis (triphenylphosphine) palladium (0) (Aldrich) 46 mg (0. (040 mmol) was mixed and heated and stirred at 120 ° C. for 18 hours in an oil bath under an argon atmosphere.
The reaction solution was concentrated under reduced pressure to remove toluene, and the residue was washed with dry ethyl acetate and extracted with dichloromethane. The dichloromethane solution was concentrated to obtain 0.11 g (0.17 mmol) of an orange powder of the compound represented by the formula (2-1). The yield was 42%.

¹ H-NMR, ¹³ C-NMR, and MS spectra of the obtained compound are as follows.
^{· 1 H-NMR (200MHz,} CDCl 3) σ7.24 (AB, J = 3.5Hz, 2H), 7.14 (AB, J = 3.5Hz, 2H), 7.10 (AB, J = 3 .8 Hz, 2H), 7.07 (AB, J = 3.8 Hz, 2H) 7.07 (s, 2H), 0.94 (s, 18H), 0.31 (s, 12H) ppm

^{· 13 C-NMR (50MHz,} CDCl 3) σ141.98,137.09,136.29,135.89,135.83,135.66,124.77,124.34,124.26,124.18 , 26.42, 17.02-4.83 ppm

_{· FAB-LRMS for C 32 H} 40 S 5 Si 2: 641 ([M + H] +, 60), 640 (M +, 100), 583 ([M-tBu] +, 25)

  The dried ethyl acetate layer used for washing was concentrated, and the resulting residue was washed with dry acetonitrile to give 0.0068 g (0,5'-bis (t-butyldimethylsilyl) -2,2'-bithiophene). 017 mmol) of yellow powder. The yield was 43%.

¹ H-NMR and MS spectra of the obtained compound are as follows.
^{· 1 H-NMR (200MHz,} CDCl 3) σ7.25 (AB, J = 3.5Hz, 2H), 7.13 (AB, J = 3.5Hz, 2H), 7.13 (AB, J = 3 .5Hz, 2H) 0.95 (s, 18H), 0.30 (s, 12H) ppm

FAB-LRMS for C ₃₀ H ₃₄ S ₂ Si ₂ : 396 ([M + 2] ⁺ , 4), 395 ([M + 1] ⁺ , 7), 394 (M ⁺ , 13), 379 ([M-Me] ⁺ , 1), 337 ({Mt-Bu} ⁺ , 14)

[Production of compound represented by formula (2-2)]
Compound represented by formula (2-2) (5,5 ″ ″-bis (dimethylphenylsilyl) -2,2 ′: 5 ′, 2 ″: 5 ″, 2 ′ ″: 5 ′ ″, 2 ""-kinkathiophene) production method and compound data are shown.

[1] Production of 2-tributylstannyl-5- (dimethylphenylsilyl) thiophene In a solution of 0.42 g (5.0 mmol) of thiophene in 10 ml of tetrahydrofuran and kept at −30 ° C. in an argon atmosphere, butyllithium was added. 1.9 ml (5.0 mmol, hexane solution) was added dropwise. After this mixed solution was stirred at the same temperature for 2 hours, 0.88 g (5.2 mmol) of chlorodimethylphenylsilane (manufactured by Aldrich) was added, and the mixture was further stirred at the same temperature for 1 hour. To this mixed solution, 2.4 ml (6.2 mmol, hexane solution) of butyllithium was added dropwise and stirred for 2 hours at the same temperature. Then, 2.0 g (6.0 mmol) of chlorotributyltin was added, and the mixture was further stirred for 1 hour at the same temperature. Stir. The mixed solution was stirred at room temperature overnight, diluted with diethyl ether, and poured into a vigorously stirred ice-cold saturated brine. The organic layer was washed with saturated brine, dried over anhydrous sodium sulfate, and then concentrated under reduced pressure to obtain 2.9 g of a crude product.
This crude product was subjected to Kugelrohr distillation at 200 ° C. and 0.3 Torr to obtain 1.6 g of 2-tributylstannyl-5- (dimethylphenylsilyl) thiophene. The yield was 64%.

[2] Preparation of compound represented by formula (2-2) To 8 ml of toluene, 0.81 g (1.6 mmol) of 2-tributylstannyl-5- (dimethylphenylsilyl) thiophene and 5,5 ″- A solution prepared by mixing 0.32 g (0.8 mmol) of dibromo-2,2 ′: 5 ′, 2 ″ -terthiophene with 92 mg (0.080 mmol) of tetrakis (triphenylphosphine) palladium (0) The mixture was heated and stirred in a bath at 120 ° C. for 18 hours.
The reaction solution was concentrated under reduced pressure to remove toluene, and the residue was washed with dry ethyl acetate and extracted with dichloromethane. The dichloromethane solution was concentrated to obtain 0.31 g (0.46 mmol) of an orange powder of the compound represented by the formula (2-2). The yield was 57%.

¹ H-NMR, ¹³ C-NMR, and MS spectra of the obtained compound are as follows.
^{· 1 H-NMR (200MHz,} CDCl 3) σ7.55-7.62 (m, 4H), 7.35-7.43 (m, 6H), 7.24 (AB, J = 3.6Hz, 2H ), 7.16 (AB, J = 3.6 Hz, 2H), 7.09 (AB, J = 3.8 Hz, 2H) 7.07 (s, 2H), 7.06 (AB, J = 3. 8Hz, 2H), 0.61 (s, 12H) ppm

¹³ C-NMR (50 MHz, CDCl ₃ ) σ 142.72, 137.95, 137.93, 136.37, 136.07, 136.04, 135.97, 133.85, 129.41, 127.88 125.04, 124.55, 124.34, 124.29, -1.22 ppm

[Production of compound represented by formula (2-3)]
Compound represented by formula (2-3) (5,5 ″ ″-bis (trioctylsilyl) -2,2 ′: 5 ′, 2 ″: 5 ″, 2 ′ ″: 5 ′ ″, 2 ""-kinkathiophene) production method and compound data are shown.

[1] Preparation of 2-tributylstannyl-5- (trioctylsilyl) thiophene In a solution of 0.42 g (5.0 mmol) of thiophene in 10 ml of tetrahydrofuran and kept at −30 ° C. in an argon atmosphere, butyllithium was added. 3.3 ml (5 mmol, hexane solution) was added dropwise. After stirring this mixed solution at the same temperature for 2 hours, 1.9 g (5.2 mmol) of chlorotrioctylsilane (manufactured by Aldrich) was added, and the mixture was further stirred at the same temperature for 1 hour. To this mixed solution, 3.4 ml (5.2 mmol, hexane solution) of butyllithium was added dropwise and stirred at the same temperature for 2 hours. Then, 1.9 g (5.2 mmol) of chlorotributyltin was added, and further at the same temperature for 1 hour. Stir. The mixed solution was stirred at room temperature overnight, diluted with diethyl ether, and poured into a vigorously stirred ice-cold saturated brine. The organic layer was washed with saturated brine, dried over anhydrous sodium sulfate, and then concentrated under reduced pressure to obtain 3.7 g of a crude product.
This crude product was subjected to Kugelrohr distillation at 250 ° C. and 0.3 Torr to obtain 2.3 g of 2-tributylstannyl-5- (trioctylsilyl) thiophene. The yield was 63%.

[2] Preparation of compound represented by formula (2-3) To 6 ml of toluene, 0.90 g (1.22 mmol) of 2-tributylstannyl-5- (trioctylsilyl) thiophene and 5,5 ″- A solution obtained by mixing 0.25 g (0.61 mmol) of dibromo-2,2 ′: 5 ′, 2 ″ -terthiophene and 70 mg (0.061 mmol) of tetrakis (triphenylphosphine) palladium (0) The mixture was heated and stirred in a bath at 120 ° C. for 18 hours.
The residue from which volatile components were removed by distillation under reduced pressure at 120 ° C. and 0.3 Torr was purified by volume exclusion chromatography, and 0.26 g (0.22 mmol) of an orange oily substance represented by the formula (2-3) was obtained. Obtained. The yield was 37%.

¹ H-NMR, ¹³ C-NMR, and MS spectra of the obtained compound are as follows.
^{· 1 H-NMR (200MHz,} CDCl 3) σ7.24 (AB, J = 3.5Hz, 2H), 7.12 (AB, J = 3.5Hz, 2H), 7.10 (AB, J = 3 .8 Hz, 2H), 7.07 (AB, J = 3.8 Hz, 2H), 7.07 (s, 2H), 1.22-1.46 (m, 72H), 0.76-0.96 (M, 30H) ppm

¹³ C-NMR (50 MHz, CDCl ₃ ) σ 141.85, 137.61, 136.48, 135.97, 135.66, 135.34, 124.84, 124.31, 124.26, 124.16 33.69, 31.94, 29.28, 29.21, 23.73, 22.70, 14.13, 13.37 ppm.

_{· FAB-LRMS for C 68 H} 112 S 5 Si 2: 1146 ([M + H] +, 87), 1145 (M +, 100), 1033 ([M-Oct + H] +, 10), 1032 ([M-Oct ] ⁺ , 10)

  As by-products, 5,5 ′ ″ ″ ″-bis (trioctylsilyl) -2,2 ′: 5 ′, 2 ″: 5 ″, 2 ′ ″: 5 ′ ″, 2 '' '': 5 '' '', 2 '' '': 5 '' '' ', 2' '' '' ': 5' '' '' ', 2' '' '' ''-octa 0.077 g (0.055 mmol) of red thiophene solid was obtained. The yield was 18%.

¹ H-NMR and MS spectra of the obtained compound are as follows.
¹ H-NMR (200 MHz, CDCl ₃ ) σ 7.23 (AB, J = 3.5 Hz, 2H), 7.12 (AB, J = 3.5 Hz, 2H), 7.07 (br s, J = 3.8 Hz, 12H) 1.22-1.46 (m, 72H), 0.76-0.96 (m, 30H) ppm

¹³ C-NMR (50 MHz, CDCl ₃ ) σ 141.71, 137.62, 136.50, 136.12, 135.79, 135.63, 135.49, 135.25, 124.81, 124.29 , 124.12, 33.75, 32.01, 31.66, 29.34, 29.28, 23.81, 22.78, 22.74, 14.22, 13.49 ppm.

FAB-LRMS for C ₈₀ H ₁₁₈ S ₈ Si ₂ : 1391 ([M + H] ⁺ ), 1390 (M ⁺ )

[Production of compounds represented by formula (2-4) and formula (2-5)]
A compound represented by formula (2-4) (5,5 ′ ″-bis (decyldimethylsilyl) quarterthiophene) and a compound represented by formula (2-5) (5,5 ″ ″-bis ( The production method and compound data of (decyldimethylsilyl) pentathiophene) are shown.

[1] Production of decyldimethyl (2′-thienyl) silane (compound represented by the following formula (4-1))

  Thiophene (1.68 g, 20.0 mmol) dissolved in anhydrous THF (40 mL) was cooled to −20 ° C., and butyl lithium (13.0 mL, 20.0 mmol, 1.6 M in hexanes) was slowly added dropwise thereto over 30 minutes. . The mixed solution was warmed to room temperature and stirred for 1 hour. Again, after cooling the solution to −20 ° C., a solution of chlorodecyldimethylsilane (4.70 g, 20.0 mmol) in THF (10 mL) was quickly added. The solution was warmed to room temperature and stirred overnight, and then 50 mL of an aqueous ammonium chloride solution was added. The aqueous phase was extracted 3 times with 100 mL of diethyl ether, and then the combined organic phases were washed with 150 mL of saturated brine. The organic phase was dried over anhydrous magnesium sulfate and concentrated using an evaporator. The resulting crude product was purified by silica gel column chromatography (solvent hexane) to obtain the desired product (5.03 g) in a yield of 89%. Obtained.

TLC R _f value, ¹ H-NMR, ¹³ C-NMR, IR, and MS spectra of the obtained compound are as follows.
TLC: _Rf = 0.85 (hexanes).

¹ H-NMR (400 MHz, CDCl ₃ ): σ = 0.31 (s, 6H), 0.77 (dd, J = 9.2, J = 6.4 Hz, 2H), 0.87 (t, J = 6.6 Hz, 3H), 1.21-1.41 (m, 16H), 7.06 (dd, J = 3.8, J = 3.2 Hz, 1H), 7.27 (d, J = 3.2 Hz, 1H), 7.60 (d, J = 3.8 Hz, 1H) ppm.

^{· 13 C-NMR (100MHz,} CDCl 3): σ = -1.81,14.13,16.61,22.69,23.76,29.29,29.34,29.58,29.65 31.92, 33.49, 128.02, 130.33, 134.10, 139.21 ppm.

IR (KBr): 3076, 2922, 2853, 1499, 1465, 1407, 1250, 1213, 1082, 991, 810, 704 cm ⁻¹ .
FAB-MS: m / z = 283/282 (5/34, M ⁺ ).

[2] Production of 2-decyldimethylsilyl-5-tributylstannylthiophene (compound represented by the following formula (4-2))

  A diethyl ether solution (30 mL) of decyldimethyl (2′-thienyl) silane (compound represented by formula (4-1)) (2.82 g, 10.0 mmol) obtained by the above method was cooled to 0 ° C. Then, butyl lithium (6.25 mL, 10.0 mmol, 1.6 M in hexanes) was added dropwise over 15 minutes. The suspension was warmed to room temperature and stirred for 1 hour. The yellow reaction solution was cooled to 0 ° C. and chlorotributylstannane (3.26 g, 10.0 mmol) was added quickly. The mixture was warmed to room temperature and stirred overnight, and then 50 mL of a saturated aqueous ammonium chloride solution was added to stop the reaction. The aqueous phase was extracted 3 times with 50 mL of diethyl ether, and then the combined organic phases were washed with 50 mL of saturated brine and dried over anhydrous magnesium sulfate. The organic solvent was concentrated by an evaporator, and the obtained yellow crude product (5.44 g, 9.52 mmol, 95%) was used as it was in the next coupling reaction without purification.

Each spectrum of ¹ H-NMR, ¹³ C-NMR, IR, and MS of the obtained compound is as follows.

¹ H-NMR (400 MHz, CDCl ₃ ): σ = 0.30 (s, 6H), 0.71-0.97 (m, 14H), 0.99-1.21 (m, 6H), 1 .28-1.42 (m, 22H), 1.44-1.66 (m, 6H), 7.16-7.20 (m, 1H), 7.39 (bs, 1H) ppm.

^{· 13 C-NMR (100MHz,} CDCl 3): σ = -1.63,10.84,13.66,14.13,16.78,17.51,22.70,23.83,27.27 28.96, 29.32, 29.35, 29.68, 31.93, 33.53, 134.87, 136.09, 142.13, 144.97 ppm.

IR (KBr): 2955, 2922, 2853, 1466, 1250, 1200, 1105, 837, 769 cm ⁻¹ .
FAB-MS: m / z = 516/515/514/513/512 (25/100/44/76/50, M ⁺ -C ₄ H ₉ ).

[3] Preparation of compound represented by formula (2-4) 15 mL of an anhydrous toluene solution of 5,5｀-dibromo-2,2′-bithiophene (311 mg, 960 mmol) was carefully degassed with argon, and then the above method 2-decyldimethylsilyl-5-tributylstannylthiophene (compound represented by formula (4-2)) (1.65 g, 2.88 mmol) obtained in (1) was added. After adding Pd (PPh ₃ ) ₄ (65.4 mg, 144 mmol, 15 mol%), the reaction solution was heated at 120 ° C. for 24 hours. After the solvent was distilled off under reduced pressure, the crude product was washed with acetonitrile. The remaining solid was dissolved in 100 mL of dichloromethane and filtered. Silica gel was added to the filtrate to adsorb the product, and then the solvent was distilled off under reduced pressure to obtain silica gel carrying the product. This was packed in a column tube, and the product was purified using a mixed solvent of hexane / dichloromethane to obtain the desired product as a yellow solid (551 mg, yield 79%).

Mp of the obtained compound (melting point. The solvent in parentheses indicates a recrystallization solvent for crystals subjected to melting point measurement), TLC R _f value, ¹ H-NMR, ¹³ C-NMR, IR, Each spectrum of MS is as follows.

Mp: 70 ° C. (hexanes / dichloromethane).
TLC: R _f = 0.70 (hexanes: dichloromethane = 7: 1).

¹ H-NMR (400 MHz, CDCl ₃ ): σ = 0.31 (s, 12H), 0.78 (dd, J = 9.2, J = 6.4 Hz, 4H), 0.88 (t, J = 6.6 Hz, 6H), 1.22-1.42 (m, 32H), 7.06 (d, J = 3.8 Hz, 2H), 7.09 (d, J = 3.8 Hz, 2H) ), 7.13 (d, J = 3.4 Hz, 2H), 7.23 (d, J = 3.4 Hz, 2H) ppm.

^{· 13 C-NMR (100MHz,} CDCl 3): σ = -1.92,14.13,16.49,22.69,23.79,29.29,29.35,29.59,29.66 31.92, 33.47, 124.21, 124.39, 124.93, 134.98, 135.91, 136.30, 139.30, 141.98 ppm.

IR (KBr): 3057, 2957, 2920, 2851, 1425, 1257, 1070, 984, 835, 802, 789 cm ⁻¹ .
FAB-MS: m / z = 728/727/726/725 (22/31/41/7, M ⁺ ).

[4] Production of compound represented by formula (2-5) According to the same procedure as 5,5 ′ ″-bis (decyldimethylsilyl) quarterthiophene (compound represented by formula (2-4)), 5 , 5 ″ -dibromo-2,2 ′: 5 ′, 2 ″ -terthiophene and 2-decyldimethylsilyl-5-tributylstannylthiophene (compound represented by formula (4-2)) as a bright orange solid As a yield of 76%.

Mp, TLC R _f value, ¹ H-NMR, ¹³ C-NMR, IR and MS spectra of the obtained compound are as follows.

・ Mp. : 101-103 ° C. (hexanes / dichloromethane).
TLC: R _f = 0.65 (hexanes: dichloromethane = 7: 1).

¹ H-NMR (400 MHz, CDCl ₃ ): σ = 0.32 (s, 12H), 0.79 (dd, J = 9.2, 6.4 Hz, 4H), 0.89 (t, J = 6.6 Hz, 6H), 1.21-1.41 (m, 32H), 7.07 (s, 2H), 7.07 (d, J = 3.2 Hz, 2H), 7.10 (d, J = 3.2 Hz, 2H), 7.14 (d, J = 3.4 Hz, 2H), 7.23 (d, J = 3.4 Hz, 2H) ppm.

^{· 13 C-NMR (100MHz,} CDCl 3): σ = -1.93,14.13,16.48,22.69,23.74,29.29,29.35,29.59,29.65 31.92, 33.47, 124.23, 124.32, 124.40, 124.95, 134.98, 135.75, 135.97, 136.41, 139.34, 141.93 ppm.

IR (KBr): 3059, 2955, 2920, 2851, 1442, 1427, 1250, 1070, 988, 837, 791 cm ⁻¹ .
FAB-MS: m / z = 810/809/808/807 (14/19/26/3, M ⁺ ).

(Example 2) [Excitation energy of oligothiophene compound and azide compound]
Using the transient absorption measuring apparatus shown in FIG. 3, the T ₁ -T _n absorption of the compound represented by Formula (2-3), which is an energy donor, is measured, and phosphorescence when falling from T ₁ to S ₀ is measured. Was measured. In this apparatus, the second harmonic or the third harmonic obtained through the second harmonic generator (SHG) or the third harmonic generator (THG) of the Q-switched YAG laser is used as pump light, and xenon is used. Using lamp light as probe light, T ₁ -T _n absorption or T ₁ -S ₀ (phosphorescence) of thiophene can be measured. As a result of the measurement, it was found that the T ₁ -T _n absorption was 650 nm, the T ₁ -S ₀ energy was 820 nm, and from these, the S ₀ -T _n energy was found to be 360 nm. It was. From the results of normal absorption spectrum measurement, it was also found that S ₀ -S ₁ absorption was 405 nm.

Next, the S ₀ -T ₁ energy of the toluene solution of the compound represented by the compound (3-1) as an energy acceptor and the compound represented by (3-2) (manufactured by Toyo Gosei Co., Ltd.) is shown in FIG. It measured using the apparatus shown in. As a result, it was found that the compound (3-1) was 440 nm and the compound (3-2) was 500 nm.
From these results, it is experimentally confirmed that a suitable energy acceptor for the thiophene compound represented by the formula (2-3) is an azide compound represented by the formula (3-1) or the formula (3-2). confirmed. Of course, for the thiophene compound, even if the side chain shape is slightly different, the energy level does not vary greatly from the current measurement value. For example, the thiophene compound represented by the formula (2-1) Even when is used, an azide compound represented by the formula (3-1) or the formula (3-2) can be used as an energy acceptor.

(Example 3) [Production of optical storage medium]
As an energy donor, a compound represented by the formula (2-1) (5,5 ″ ″-bis (t-butyldimethylsilyl) -2,2 ′: 5 ′, 2 ″: 5 ″, 2 ″ Thin films suitable for optical experiments were prepared using DZDS or BAP-P as an energy acceptor.

  First, solvent tetrahydrofuran (THF) (concentration 5.6 wt%) is added to thiophene (concentration 0.1 wt%) and azide DZDS (concentration 0.4 wt%) or BAP-P (concentration 0.4 wt%), and heated to dissolve. Further, a mixed solution of optical cycloolefin polymer (manufactured by ZEON Corporation: trade name ZEONEX, concentration 37.6 wt%) and mesitylene (concentration 56.3 wt%) is further added, and heated again to be dissolved. Thus, an optical storage medium solution shown in FIG.

  Here, THF was used as a solvent for dissolving the pentathiophene of formula (2-1) and azide DZDS or BAP-P (THF can be dissolved at room temperature), but in addition, four solvents (xylene, monochlorobenzene, Toluene and mesitylene) were confirmed to be soluble under heating. Among these four solvents, mesitylene was the most suitable and had the maximum transparency when the solution returned to room temperature after heating. As a polymer in which pentathiophene of formula (2-1) and azide are dispersed, polymethyl methacrylate (PMMA), cyanoacrylate, and the like have been variously studied. As a result, an optical cycloolefin polymer (manufactured by Nippon Zeon Co., Ltd .: product) The name ZEONEX) was found to be optimal. However, PMMA and cyanoacrylate can also be good dispersion media if the side chain of pentathiophene is chemically modified to increase solubility.

  Mesitylene was optimal as a solvent for dissolving optical cycloolefin polymer (manufactured by Nippon Zeon Co., Ltd .: trade name ZEONEX), and pentathiophene of formula (2-1) and azide DZDS or BAP-P were dissolved. Since mesitylene was also suitable as a solvent, mesitylene was used as a solvent for an optical cycloolefin polymer (made by Nippon Zeon Co., Ltd .: trade name ZEONEX) solution added to a THF solution of pentathiophene and azide of formula (2-1). It was. This mixed solution also had transparency and uniformity suitable for optical experiments when it returned to room temperature.

  In this embodiment, as a substrate for preparing a solution for an optical storage medium that is flattened by sweeping the substrate with a blade that maintains a constant distance from the substrate in FIGS. However, the present invention is not limited to this, and any glass substrate may be used as long as the surface of the quartz substrate and the like itself is flat.

  In the step of FIG. 2D, the solvent (THF, mesitylene) was removed by baking in an oven at 90 ° C. for 60 minutes. The concentration of each component after baking was 0.3 wt% for thiophene, 1.0 wt% for both DZDS or BAP-P, and 98.7 wt% for optical cycloolefin polymer (product name: ZEONEX, manufactured by Nippon Zeon Co., Ltd.). became. If the baking time was 90 ° C. and 60 minutes, the amount of residual solvent could be reduced to a level that would not hinder optical experiments. Since the distance between the blade and the substrate can be arbitrarily changed, the film thickness after film formation can be controlled by this distance.

  Although the film having passed through FIG. 2 (d) has sufficient uniformity for optical storage experiments, there was a problem in flatness. In this example, the medium was peeled off from the slide glass in a vise. A thermocompression bonding step (FIG. 2 (f)) was performed by sandwiching and maintaining heating at 100 ° C. for 30 minutes under pressure.

  When sandwiched with a vise, a slide glass was pasted on both sides of the membrane, and a sandwich medium was sandwiched between the slide glasses. The pressure of the vise was set to a magnitude just before the slide glass was broken. The applied pressure was varied in this range, and several trials were conducted. It did not significantly affect the thickness and quality of the film to be produced. It was confirmed that the film thickness and quality were almost constant even at pressure. The baking in FIG. 2 (f) was performed by placing the sample in a baking furnace with the vise sandwiched between them.

  In the case of the above DZDS and BAP-P solutions, the film when reaching FIG. 2G is 170 μm in thickness when the distance between the blade and the substrate in FIGS. 2B and 2C is 500 μm. there were. It was confirmed that the film quality has not only striae but also flatness of the surface of the medium that sufficiently contributes to the hologram experiment described later.

  If the produced optical storage medium is thin, for example, if two samples passed through FIG. 2G are stacked and thermally compressed in the same manner as in FIG. 2F, a thick optical storage medium is obtained. Is obtained (FIG. 2 (h)). Using the above DZDS and BAP-P solution, a film having a film thickness of 170 μm was prepared, and two of these films were stacked and subjected to thermocompression bonding. The baking temperature was 100 ° C., and this was performed for 90 minutes. Also in this process, it was confirmed that the film quality had not only striae but also flatness that sufficiently contributed to the hologram experiment of Example 4.

  In this example, it was confirmed from the state of FIG. 2C that the thermocompression bonding process can be performed without removing the medium from the slide glass. When another slide glass was affixed to the medium on the side not attached to the slide glass, and then, the media having exactly the same film quality and film thickness as those described above could be produced according to the steps shown in FIG.

Example 4 [Hologram Experiment]
Using the medium obtained in Example 3, a hologram experiment was performed in the system shown in FIG. 4 to measure the time dependency of the diffraction efficiency. In the hologram experiment, the obtained medium (thickness 250 μm) was placed at the position of Sample in FIG. 4 and irradiated with gate light (Gate Laser) to perform first excitation. Next, using a holographic laser as a second excitation laser, a beam splitter (BS) and a reference light (Reference light) and an object light (Object)
light), and each medium was irradiated.

  In this configuration, interference fringes generated by the object light and the reference light, which are the second excitation light, are fixed as a change in refractive index in the memory medium in the area in the memorizable state excited by the gate light. By measuring the ratio of the reference light diffracted from the interference fringes, it is possible to know the potential as an optical storage medium.

In this example, a GaN laser (continuous light) having a wavelength of 410 nm was used as the first excitation light, and a semiconductor laser (continuous light) having a wavelength of 660 nm was used as the second excitation light. The angle formed by the object beam and the reference beam was 2 degrees. The spot size of incident light was 250 μm. The intensity of the incident light was 0.10 W / cm ^{2 for} the first excitation light, and 20 W / cm ² for the second excitation light for both the reference light and the object light.

In the configuration in FIG. 4, the diffraction efficiency can be measured by temporarily blocking the object light during the measurement and measuring the ratio at which the reference light is diffracted by the interference fringes generated in the memory medium. FIG. 5 shows the results of measuring the time dependency of the diffraction efficiency. This is a diagram in which the amount of reference light passing through the sample is measured, and then the ratio of the diffracted light (Efficiency η (%)) is measured, and the time dependence thereof is plotted. In the figure, (1) indicates that the first excitation light is blocked and the second excitation light (both reference light and object light) is incident, and (2) indicates that the first excitation light is incident. A case where both light and second excitation light (both reference light and object light) are input is shown. From the experimental results, it was found that in the case of (2), the diffraction efficiency increases in proportion to the square of the irradiation time almost as calculated, whereas in the state of (1), the diffraction efficiency does not increase. When the first excitation light was irradiated and only either the object light or the reference light was irradiated among the second excitation light, no increase in diffraction efficiency was observed. This time, interference fringes were generated and diffraction of the object light was observed only when the sample was irradiated with three beams of the first excitation (gate) light and the second excitation light (both reference light and object light). The results show that interference fringes were formed in the optical storage medium of the present invention through a two-step excitation process.
In addition, the results here show that the energy level investigated in Example 2 is correct, and that the above-described interference fringes due to structural changes caused by the energy transfer from thiophene to azide can be formed. Prove that the person's way of thinking is correct.

  Even when the thin film medium having a film thickness of 170 μm produced in Example 3 was used, the diffracted light of the reference light was observed. The diffraction efficiency is predicted to be proportional to the square of the film thickness, but the intensity in the experiment is 1/7 times the result at the film thickness of 250 μm. In calculation, it should be 1 / 6.25 times, showing good agreement.

  The absolute value of the diffraction efficiency in FIG. 5 is as small as about 0.01% because the power or optical power density of the laser light source used in this embodiment (= can be increased or decreased depending on the focal length of the condensing lens) is low. This can be improved by using a higher-intensity laser or changing the focal length of the condenser lens to a shorter one. The pentathiophene film has sufficient light resistance.

  FIG. 6 is a result of normalizing and plotting the diffraction efficiency (experimental result) of the conventional material biacetyl in accordance with the experimental conditions such as the irradiation light intensity in FIG. In biacetyl, the wavelength of the first excitation light is 410 nm, which is the same as that of thiophene, but the wavelength of the second excitation light is 830 nm. This is based on energy level differences. The film thickness of the biacetyl film was 500 μm. Biacetyl was produced by a method of enclosing a biacetyl solution in a quartz cell having an optical path length of 500 μm. As the biacetyl dispersion medium, cyanoacrylate was used, and the biacetyl concentration was 10 wt%.

  FIG. 6 shows that the potential of thiophene is about two orders of magnitude or more of biacetyl, considering that the concentration of thiophene in the medium produced this time is 1/30 times that of biacetyl and the difference in film thickness. That is, in this example, a medium having a thiophene concentration of 0.3 wt% was produced, but an optical storage medium was produced by setting the thiophene concentration to the same level as that of biacetyl (with a corresponding increase in the azide concentration). If the film thickness is the same as that of thiophene, the efficiency of the actually obtained medium is 2 digits or more.

  Therefore, if thinning is performed using a medium in which thiophene is dispersed at a high concentration, practical diffracted light, for example, even in a thinned medium considered impossible with biacetyl, that is, a medium thinned to the order of several μm. Will be observable.

  In Example 4, the state in which the structural change (refractive index change) based on light irradiation occurs in the optical storage medium through the two-step excitation process is shown in the second excitation area (gate light) in the second area. Although the reference light is observed by the phenomenon that the reference light is diffracted by the interference fringes generated by the two-beam interference between the object light that is the excitation light and the reference light, the optical storage medium that has undergone the two-step excitation process intended by the present invention is not limited thereto. The second excitation light may be one. As shown in FIG. 8, the lowest triplet state that can be recorded by the first excitation is obtained, and even if only one second excitation light is irradiated there, the structural change (refractive index change) occurs. If the change caused by the second excitation light irradiation is read by irradiating another light and observing the change in transmittance, optical storage / reproduction can be performed. In Example 4, the appearance of the structural change (refractive index change) was merely confirmed by observing the diffracted light.

  Therefore, in the three-dimensional optical storage medium, if the first excitation light and the second excitation light are irradiated, the structural change (refractive index change) occurs only in the overlapping portion of the two. In a three-dimensional medium, for example, a medium in which DVD storage layers are stacked in multiple layers, optical storage / reproduction without the problem of data erasure as in the one-step excitation process described in FIG. 7 is possible.

(Example 5)
Using the thiophene represented by the formulas (2-4) and (2-5), an experiment similar to that of Example 3 was performed (the concentration and the film thickness are the same as those of Example 3). Furthermore, an optically good thin film could be produced by a spin coating method. In the production by the spin coat method, pentathiophene was dissolved in mesitylene, DZDS was added, and the mixture was dissolved under heating. A mesitylene solution of an optical cycloolefin polymer (manufactured by Nippon Zeon Co., Ltd .: trade name ZEONEX) was added and dissolved therein, and a thin film was prepared with a spinter. The rotation speed of the spin coater was 1500 rpm. The prepared spin coat thin film is 0.3 wt% thiophene represented by formulas (2-4) and (2-5), 1.0 wt% DZDS, and an optical cycloolefin polymer (Nippon Zeon Corporation). Product: ZEONEX) was 98.7 wt%. Both film thicknesses were 45 μm.

(Example 6)
A hologram experiment similar to that of Example 4 was performed using a film manufactured according to Example 5 using thiophene represented by Formula (2-5). As a result of using a medium produced by the same method as in Example 3 (the optical system such as the applied wavelength is the same), similar hologram diffraction could be observed. Next, in the experiment using the spin coat thin film, although the signal intensity decreased corresponding to the decrease in the film thickness, the produced thin film had sufficient light resistance. It was possible to obtain a result having the same efficiency as that of FIGS. 5 and 6 by increasing the light intensity of. However, for materials with a large absorption coefficient of the first excitation light, such as thiophene, the physical thickness and the effective length become closer as the physical thickness of the medium decreases (the effective length decreases as the physical thickness decreases). Does not decrease). For this reason, in the result examined in this example, a diffraction efficiency about twice as large as expected from the difference in physical thickness between the medium 170 μm and the spin coat thin film 45 μm produced by the same method as in Example 3 is obtained. It was possible. That is, the result of the spin coat thin film of the present example is that the thiophene film according to the present invention has a thick film produced by the method of Example 3, and according to the thiophene film of the present invention, the thiophene thin film medium This supported the realization of practical hologram diffraction.

Schematic diagram of energy excited states showing the relationship between energy donor and energy acceptor energy acceptance. The figure which shows the manufacturing process of the optical storage medium by the blade coat method and the thermocompression bonding method Schematic diagram showing a transient absorption measurement device that measures the excitation energy of a compound Schematic diagram showing the method of hologram experiment Graph showing the result of hologram experiment (ratio of diffracted light-time) Graph showing results of hologram experiment (compared with conventional material biacetyl) Schematic showing the problems of conventional one-stage excitation memory Schematic diagram of the energy excitation state showing the relationship between data recording and optical excitation.

Claims (8)

  Excited to the singlet excited state by the first excitation light irradiation, then moved to the lowest triplet excited state by intersystem crossing, and subsequently excited to the higher triplet excited state by the second excitation light irradiation. An optical storage medium comprising an organic mixture, comprising: a two-stage excitation type energy donor; and an energy acceptor that receives energy from the energy donor and supplies the energy to a chemical reaction. 2. The optical storage medium according to claim 1, wherein the energy donor is an oligothiophene compound represented by any one of the following formulas (1-1) to (1-4).

(In the formulas (1-1) to (1-4), X _{1 to} X ₆ , X _{7a to} X _7b , X _{8a to} X _8d , X _9a
-X _9f is a group selected from a hydrogen atom, an alkyl group, a group in which some carbon atoms of the alkyl group are replaced with a silicon atom, a group having a halogen, a hydroxyl group, an alkyloxy group or an aryloxy group, or a dialkylamino group Indicates. X _{1 to} X ₆ , X _{7a to} X _7b , X _{8a to} X _8d , and X _{9a to} X _9f may be the same or different. ) The optical storage medium according to claim 2, wherein the energy donor is an oligothiophene compound represented by the following formula (2).

In (Equation (2), R ₁ ~R ₆ represents a hydrogen atom, an alkyl group, a halogen, a hydroxyl, group having an alkyl group or an aryloxy group, or a group selected from a dialkylamino group. The, R ₁ ˜R ₆ may be the same or different, and n represents 4 or 5.) The R _{1 to} R ₆ are selected from an alkyl group having 1 to 2 carbon atoms, an alkyl group having 6 to 10 carbon atoms, an aryl group, an alkenyl group, an alkynyl group, an alkoxy group, a pyridyl group, and a thiophene ring. The optical storage medium described. The optical storage medium according to claim 3, wherein the energy donor is an oligothiophene compound represented by any one of the following formulas (2-1) to (2-5).

The optical storage medium according to any one of claims 1 to 5, wherein the energy acceptor is an azide compound represented by the following formula (3).

(In formula (3), Y represents a group having at least one group selected from an alkyl group, halogen, azide group, sulfonyl group, aryl group, hydroxyl group and alkoxy group, or a hydrogen atom.) The optical storage medium according to claim 6, wherein the energy acceptor is represented by the following formula (3-1) or (3-2).

  An energy donor according to any one of claims 1 to 5 and a solution for an optical storage medium in which the energy acceptor according to claim 6 or 7 is dispersed are dropped on a substrate, and then the distance from the substrate A thin film type optical storage medium including a sweeping process for planarizing the solution for optical storage medium by sweeping the substrate with a blade that keeps the constant, and further a heating process for improving flatness by heating under pressure A method for manufacturing an optical storage medium.

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