JP2006249205A - Photochromic material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a photochromic material that does not deteriorate recording information in reading out recording information. <P>SOLUTION: The photochromic material comprises a diarylethene containing an optically active amphipathic functional group, preferably a compound represented by formula (R is an oligo(ethylene glycol) chain that has at least one optically active part and the number of repeating units of 6-12). Since a CD (circular dichroism) spectrum reversibly changes according to ultraviolet/visible light irradiation, a readout is performed by an optical rotation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photochromic material, and more particularly to a novel photochromic material useful as an optical recording material or the like comprising a compound having a diarylethene structure.

  Diarylethene has a structure in which aryl groups are bonded to both sides of the central ethene ring. When irradiated with ultraviolet light, the central hexatriene part changes from a ring-opened structure to a closed ring structure, and returns to its original state when irradiated with visible light. A compound. This structural change brings about a color change, and various colors are developed due to the difference in substituents, and application to optical recording materials and the like has been attempted taking advantage of this characteristic.

  When diarylethene is used as an optical recording material, in the detection (readout) method using the absorption change of diarylethene itself, photoisomerization is promoted by the light used for detection, and it is recorded as information is detected several times. Destruction of information occurs. In order to eliminate such inconveniences, the present inventors first introduced an isomer having a specific structure into diarylethene, whereby an isomer having an optical rotation in a wavelength region where diarylethene does not absorb (ring-closed) is obtained. A photochromic material has been devised which is produced enantioselectively and thereby allows the recorded information accompanying the isomerization of diarylethene to be read out through the optical rotation (for example, JP-A-10-60424): Patent Document 1).

This method is one of the effective methods for non-destructive readout of recorded information in diarylethene optical recording materials, but in order to further develop diarylethene compounds as photochromic materials, a non-destructive approach based on another approach is required. A destructive detection method is desired.
Japanese Patent Laid-Open No. 10-60424

  An object of the present invention is to provide a new type of photochromic material in which recorded information is not deteriorated when the recorded information is read.

  The present invention finds that in diarylethene compounds having an optically active amphiphilic substituent, the ring-closed compound exhibits optical activity and expresses a CD (circular dichroism) signal, and this characteristic is used to degrade information. The present invention has been derived by conceiving that reading can be performed without accompanying the above.

  Thus, the present invention provides a photochromic material characterized by comprising a compound represented by the following general formula (I).

In the formula (I), A is a ring composed of an aliphatic ring, an acid anhydride ring, or a maleimide ring, which may contain a fluorine atom, and X represents a sulfur atom, an oxygen atom, or a nitrogen atom. , At least one of R ^{1 to} R ⁶ represents an optically active amphiphilic functional group.

  In the photochromic material of the present invention, the CD spectrum reversibly changes in response to the irradiation with ultraviolet / visible light. Based on this characteristic, nondestructive reading of recorded information based on the optical rotation becomes possible.

In the above-described formula (I), A is a so-called ethene ring, which is composed of any of an aliphatic ring, an acid anhydride ring, and a maleimide ring, for example, having a structure as shown in FIG. . An amphiphilic functional group corresponding to at least one of R ^{1 to} R ⁶ is preferably an oligoethylene glycol chain as described later, but in addition to this, an oligoamide, an alkyl phosphoric acid, an alkyl sulfonic acid, etc. Is possible.

  Although the principle of the present invention can be generally applied to diarylethene compounds represented by the formula (I), compounds represented by the following formula (II) are preferred as the photochromic material of the present invention.

  In the formula (II), R is an oligoethylene glycol chain having at least one optically active site (chiral site), and the number of repeating units of the oligoethylene glycol chain is 6 to 12 in order to exhibit amphiphilic properties in water. is there. Thus, examples of particularly preferred compounds of the photochromic material of the present invention include diarylethene compounds represented by the following formula (III).

In formula (III), * represents an optically active site.
In the compound represented by the formula (I), (II) or (III), a CD signal having a positive caplet in the visible range is observed as a closed ring (colored body) is formed by irradiation with ultraviolet light in water. This CD spectrum is reversibly changed by repeated irradiation with ultraviolet and visible light. And observation by DLS and AFM shows that this diarylethene compound forms an aggregate in water. Since no diastereomeric excess (de) is observed in the photocycle, the obtained reversible CD spectrum is considered to be derived from the fact that the aggregate formed by the ring-closed product exhibits chirality in water. .

As described above, since the photochromic material of the present invention exhibits a stable and reversible CD spectrum change, it can be read out using the optical rotation with respect to light having a wavelength of about 800 nm in the non-absorption region of diarylethene, At this time, there is no change in the diarylethene itself and there is no deterioration of the recorded information. That is, the photochromic material of the present invention is an unprecedented optical recording medium capable of reversibly changing asymmetric information with light by changing the degree of molecular self-assembly.
In the following, examples are given to describe the present invention more specifically.

Synthesis of Photochromic Compound A compound represented by the above-described formula (III) was synthesized as a photochromic material of the present invention according to the following steps.
<(S) -2- (Tetrahydropyran-2-yloxy) -propionic
Synthesis of acid ethyl ester (11): Step 1>

Dissolve (S) -ethyl lactate (10) (15.0 g, 127.0 mmol) in CH ₂ Cl ₂ (150 mL) that has been dried with molecular sieve (4A) for 4 hours, then 3,4-dihydro-2H-pyran (16.0 g) 191.0 mmol) and PPTS (= Pyridinium-p-toluene sulfonate) (1.6 g, 6.4 mmol). This was stirred overnight (16 h) under Ar atmosphere. Extracted with CH ₂ Cl ₂ (× 2) and washed with brine (× 3). By drying over magnesium sulfate and drying under reduced pressure, colorless oil 11 (30.12 g, 148.4 mmol) was obtained. Crude yield about 100%.
¹ H-NMR (CDCl ₃ , TMS, 200 MHz) δ 1.28 (td, J = 7 Hz, 3H, Me), 1.43 (dd, J = 7 Hz, 3H, Me), 1.46-1.94 (m,
6H, THP), 3.38-4.02 (m, 2H, THP), 4.19 (quart.d, 2H, CH ₂ ), 4.20 & 4.42 (quart., 1 H), 4.66-4.76 (m, 1 H, THP) .

<(S) -2- (Tetrahydropyran-2-yloxy) -propan-1-ol
Synthesis of (12): Step 2>

LiAlH ₄ (2.30 g, 60.7 mmol) was added to dry Et ₂ O (14.4 mL) under no water and Ar atmosphere, and dissolved in dry Et ₂ O (7.7 mL) while keeping the temperature at 0 ° C. with an ice bath ( S) -2- (Tetrahydro-pyran-2-yloxy) -propionic
Acid ethyl ester (11) (10.0 g, 49.4 mmol) was slowly added dropwise using a dropping funnel. While maintaining this at 0 ° C., the mixture was stirred for about 24 hours while gradually returning to room temperature. The mixture was further refluxed for 5 hours, returned to room temperature, and quenched by adding 10 w% NaOH (48 mg) in ethyl acetate (4 mL) and water (16 mL). This was extracted with AcOEt (x2) and washed with brine (x3). After drying over magnesium sulfate, filtration, and concentration, 12 (7.22 g, 45.1 mmol) as a transparent oil was obtained. Crude yield 91.3%.
¹ H-NMR (CDCl ₃ , TMS, 200 MHz) δ 1.18 (dd, J = 6 Hz, 3H, Me), 1.40-1.94 (m, 6H, THP), 3.36-3.74 (m, 4H), 3.74-4.10 (m, 2H), 4.50-4.78 (m, 1H, THP).

<(S) -1- {2- [2- (2- {2- [2- (2-Methoxy-ethoxy) -ethoxy]-
ethoxy} -ethoxy) -ethoxy] -ethoxy} -propan-2-ol
Synthesis of (13): Step 3>

Compound 12 (3.02g, 18.7mmol) and p-toluene
Sulfonic acid hexaethlyene glycol monomethyl ether (6) (12.8 g, 21.1 mmol) was dissolved in dry THF (100 mL), and NaH (1.27 g, 52.9 mmol) was added. This was refluxed for about 12 hours, then returned to room temperature and quenched by adding water. The reaction mixture was concentrated under reduced pressure to remove THF, extracted with CH ₂ Cl ₂ (× 2), and washed with brine (× 3). The extract was dried over magnesium sulfate, filtered, and concentrated under reduced pressure to give a yellow oily substance. In order to remove the protecting group, the next reaction was carried out without further purification. The obtained compound was dissolved in MeOH (50 mL), and kept at 0 ° C. for about 15 minutes in an ice bath, TsOH · H ₂ O (0.6 g, 3.18 mmol) was added, and the mixture was stirred at room temperature for about 4 hours. Quenched with aqueous NaHCO ₃ solution, extracted with AcOEt (× 2) and washed with brine (× 3). Dry over magnesium sulfate, filter, concentrate, and concentrate on a silica gel column (ethyl
Development was performed using acetate: acetone = 1: 1). This was dried under reduced pressure to obtain colorless oily compound 13 (2.0 g, 5.64 mmol). Yield 30.2%.
¹ H NMR (CDCl ₃ , TMS, 200 MHz) δ 1.13 (d, J = 6 Hz, 3H, Me), 3.38 (s, 3H, Me), 3.45-4.02 (m, 27 H));
FAB HRMS (m / z) [M + H] ⁺
calced for C1 ₆ H ₃₅ O ₈ ⁺ , 355.2332; found, 355.2333.

<(S) -Toluene-4-sulfonic
acid 2- {2- [2- (2- {2- [2- (2-methoxy-ethoxy)-
ethoxy] -ethoxy} -ethoxy) -ethoxy] -ethoxy} -1-methyl-ethyl
Synthesis of ester (14): Step 4>

NaOH (220 mg) was dissolved in water (0.4 mL), and compound 13 (1.5 g, 4.23 mmol) dissolved in THF (0.4 mL) was added while maintaining the temperature at 0 ° C. in an ice bath. To this, p-TsCl (890 mg, 4.65 mmol) dissolved in THF (1.0 mL) was added dropwise using a dropping funnel. This was returned to room temperature and stirred for about 7 hours. After completion of the reaction, water (40 mL) was added, and 6M H ₂ SO ₄ was added to make the solution acidic. Extracted with CH ₂ Cl ₂ (× 2) and washed with brine (× 3). The extract was dried over magnesium sulfate, filtered, concentrated, and developed and separated using a silica gel column (ethyl acetate: acetone = 1: 1). This was dried under reduced pressure to obtain colorless oil 14 (1.6 g, 3.15 mmol). Yield 74.5%.
¹ H NMR (CDCl ₃ TMS, 200 MHz) δ 1.13 (d, J = 6Hz, 3H, Me), 2.45 s, 3H, Ts), 3.38 (s, 3H, Me), 3.45-4.02 (m, 27H )), 7.35 (d, J = 8Hz, 2H,
Ar), 7.80 (d, J = 8 Hz, 2H, Ar); FAB HRMS (m / z) [M + H] ⁺
_{calced for C 23 H 41 O 10} S +, 209.2420; found, 509.2417.

<(S) -p-Iodo- (2- {2- [2- (2- {2- [2- (2-methoxy-ethoxy)-
Synthesis of ethoxy] -ethoxy} -ethoxy) -ethoxy] -ethoxy} -propoxy) -benzene (15): Step 5>

K ₂ CO ₃ (2.14 g, 15.5 mmol) was dissolved in DMF (15 mL), and compound 14 (0.80 g, 1.58 mmol) and p-iodophenol (7) (0.41 g, 1,74 mmol) were added thereto. This was stirred for about 7 hours while maintaining at 70 ° C. in an oil bath. After completion of the reaction, this was poured into water (150 mL) adjusted to pH = 2 with hydrochloric acid, extracted with CH ₂ Cl ₂ (× 2), and washed with brine (× 3). After drying with magnesium sulfate and filtering, the resultant was developed and separated using a silica gel column (ethyl acetate). This was concentrated to give oily 15 (0.96 g, 1.78 mmol). Yield 56.5%.
¹ H NMR (CDCl ₃ , TMS, 200 MHz) δ 1.29 (d,
J = 6Hz, 3H, Me), 3.38 (s, 3H, Me), 3.45-4.60 (m, 27H)), 6.71 (d, J = 9Hz, 2H, Ar), 7.53 (d, J = 9Hz, 2H , Ar); FAB HRMS (m / z)
_{^{[M] + calced for C 22}} H 37 IO 8, 556.1533; found, 556.1532.

<(S) -3-Bromo-5- [4- (2- {2- [2- (2- {2- [2- (2-methoxy-ethoxy) -ethoxy] -ethoxy}-
ethoxy) -ethoxy] -ethoxy} -1-methyl-ethoxy) -phenyl] -2-methyl-thiophene
Synthesis of (16): Step 6>

The reactor was purged with Ar and sufficiently dried. Then, compound 15 (900 mg, 1.67 mmol) was dissolved in dry THF (30 mL), and the n-butyl lithium hexane solution ( 1.6M, 1.15 mL, 1.84 mmol) was slowly added dropwise with a syringe. The mixture was stirred for about 1 hour, tri-n-butyl borate (0.672 mL, 2.51 mmol) was added, the temperature was slowly returned to room temperature, and the mixture was further stirred for 2.5 hours. After completion of the reaction, it was once quenched with water, and 2,4-dibromo-5-methylthiophene (642 mg, 2.51 mmol), NaCO ₃ aqueous solution (20 w%, 30 mL), Pd (PPh ₃ ) ₄ (96.5 mg, 0.084 mmol) were added. Each was added and refluxed at 75 ° C. overnight (12 and a half hours). This was extracted with AcOEt (x2) and washed with brine (x3). After drying with magnesium sulfate and filtration, the resultant was developed and separated on a silica gel column (ethyl acetate). This was concentrated to obtain a transparent oily 16 (400 mg, 0.66 mmol). Crude yield 39.5%.
¹ H NMR (CDCl ₃ , TMS, 200 MHz) δ1.32 (d,
J = 6Hz, 3H, Me), 2.40 (s, 3H, Me), 3.38 (s, 3H, Me), 3.52-3.80 (m, 26H), 4.57 (quart., J = 6Hz, 1H), 6.92 ( d, J = 9Hz, 2H, Ar), 6.98 (s, 1H), 7.41 (d,
J = 9Hz, 2H, Ar) ; FAB HRMS (m / z) [M] + calced for C 27 H 41 BrO 8 S, 604.1706; found, 604.1728.

<(S, S) -1,2-Bis- [5- (4- {2- [2- (2- {2- [2- (2- {2-methoxy-ethoxy} -ethoxy) -ethoxy] -
ethoxy} -ethoxy) -ethoxy] -1-methyl-ethoxy} -phenyl) -2-methyl-thiophene-3-yl]-
Synthesis of perfluorocyclopentene ((S, S) form): Step 7>

In a reactor thoroughly purged with Ar and thoroughly dried, dissolve Compound 16 (200 mg, 0.330 mmol) in dry THF (2 mL), and maintain at −78 ° C. in an acetone / dry ice bath, while maintaining an n-butyl lithium hexane solution. (1.6M, 0.227mL, 0.363mmol) was slowly added dropwise with a syringe. After stirring this for about 1 hour, perfluorocyclopentene (0.021 mL, 0.149 mmol) was dissolved in dry THF (1.2 mL) and slowly added dropwise in several portions using a dropping funnel. The mixture was further stirred for about 1 hour, and after completion of the reaction, the temperature was returned to room temperature and quenched with water. This was extracted with AcOEt (x2) and washed with brine (x3). After drying with magnesium sulfate and filtering, the resultant was developed and separated on a silica gel column (ethyl acetate: acetone = 1: 1). Further, purification by reverse phase preparative HPLC (CH ₃ CN: MeOH: H ₂ O = 9: 1: 2) gave (III) (50 mg, 0.041 mmol). Yield 19.5%.
¹ H NMR (CDCl ₃ , TMS, 200 MHz) δ 1.32 (d, J = 6 Hz, 6H, Me), 1.93 (s, 6H, Me), 3.38 (s, 6H, Me), 3.45-3.80 (m, 52H), 4.50-4.68 (m, 2H), 6.93 (d, J = 9Hz, 4H, Ar), 7.16 (s, 2H), 7.45 (d, J = 8Hz, 4H, Ar); FAB MS (m / z) [M] ⁺ 1224.74;
Anal. Calced for C ₅₉ H ₈₂ F ₆ O ₁₆ S ₂ : C 57.83, H 6.74; found: C 57.53, H 6.70;
UV-Vis (H ₂ O) λ max (ε) 295 (35000); (AcOEt) λ max (ε) 294 (50000).

Closed ring of diarylethene (III) The closed ring is Mightysil, a reversed-phase column
Separation by HPLC using RP-18 (H) GP (250-4.6) (CH ₃ CN: MeOH: H ₂ O = 9: 1: 4). The flow rate was 1.5 mL / min. The retention time was 52 minutes for the open ring and 65 minutes for the closed ring.
¹ H NMR (CDCl ₃ , TMS, 200
MHz) δ1.33 (d, J = 6Hz, 6H, Me), 2.14 (s,
6H, Me), 3.38 (s, 6H, Me), 3.45-3.80 (m, 52H), 4.50-4.68 (m, 2H), 6.57 (s, 2H), 6.94 (d,
J = 9Hz, 4H, Ar), 7.49 (d, J = 9Hz, 4H, Ar);
UV-vis (H ₂ O) (ε)
583 (16000); (AcOEt) (ε) 594 (25000).

The CD spectrum of the compound (III) synthesized in Example 1 in water was measured. The concentration was 1.6 × 10 ⁻⁵ M. The results are shown in FIG. When irradiated with ultraviolet light (313 nm), a CD signal having a positive couplet in the visible range was observed (right in FIG. 2). The CD signal disappeared when irradiated with visible light (578 nm) (left in FIG. 2). When ultraviolet light irradiation and visible light irradiation were repeated, this CD spectrum change was reversibly repeated.

  The photochromic material of the present invention is expected to be used in many fields of industry as a recording medium capable of nondestructive reading of recorded information.

The ethene ring structure in the diarylethene compound which comprises the photochromic material of this invention is illustrated. It is CD spectrum figure measured about a desirable example of the photochromic material of the present invention, and shows the chemical structure of a ring-opened body and a ring-closed body together.

Claims (2)

A photochromic material comprising a compound represented by the following general formula (I):

(In the formula (I), A is a ring composed of an aliphatic ring, an acid anhydride ring, or a maleimide ring, which may contain a fluorine atom, and X represents a sulfur atom, an oxygen atom, or a nitrogen atom. And at least one of R ^{1 to} R ⁶ represents an optically active amphiphilic functional group.) The photochromic material according to claim 1, wherein the compound of the formula (I) is represented by the following formula (II).

(In formula (II), R represents an oligoethylene glycol chain having at least one optically active site and having 6 to 12 repeating units.)

Images