JP2588322B2 - Molecular aggregate formation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a molecular association of a photochromic compound, particularly a spiropyran compound, in an LB film.

[0002]

2. Description of the Related Art As a means for improving the stability of a colored body of photochromic molecules, there are a method of imparting stability to each molecule by molecular design, and a method of forming an aggregate which is a molecular assembly and forming an interaction between the molecules. There is a method of providing stability by action. The latter has the advantage of improving the stability of the colored body of photochromic molecules, which is difficult to realize with individual molecules as compared to the former. For example, a method of improving the stability of a colored body by forming a J-aggregate has been performed, but there have been few successful cases. Specifically, as a means for forming an aggregate of a spiropyran compound in the LB film, a method of irradiating ultraviolet rays after film formation and applying heat to form a J aggregate [E. Ando, et al,
Thin Solid Films, 133 (1985) 21] is known.
Also, there have been few attempts to stabilize the color development state using H-aggregates.

[0003]

For example, in a spiropyran compound (hereinafter abbreviated as SP18PICl) shown in FIG. 1, the formation of a J-aggregate by the above-mentioned method could not be realized, and the merocyanine type was also unstable. The present invention aims to prolong the life of a color-developed state in an LB film by forming an H aggregate.

[0004]

According to the present invention, an H-aggregate is formed by irradiating a spiropyran compound with ultraviolet rays during the compression process and the accumulation process after development during film formation by the LB method. Furthermore, in the method of the present invention, CdCl ₂ is added to the lower layer (pure water) (usually 20 to 8).
0 mg / l) can promote H-aggregate formation. Further, by optimizing the surface pressure, the formation of the H aggregate can be facilitated. Furthermore, the water temperature of the trough is 20-25 °
Maintaining C, preferably around 22 ° C., is also considered essential for the formation of H-aggregates.

The present invention can be applied to various spiropyran compounds having photochromic properties, and specific examples thereof include the following:

Embedded image [In the formula, X represents a long-chain alkyl group having 12 to 18 carbon atoms, and Y represents a halogen atom, a lower alkoxy group or a piperidino group which may be in the form of a salt. And a spiropyran derivative represented by the following formula: In the above definition, a halogen atom includes a chlorine, bromine or iodine atom, and a lower alkoxy group includes a methoxy, ethoxy, propoxy or butoxy group.

[0006]

By irradiating ultraviolet rays during the compression process and the accumulation process during film formation by the LB method, for example, a normal merocyanine-type absorption peak [ultraviolet light irradiation for 3 minutes after film formation λmax = 600 nm (FIG. 3-B, Table 1-No. 1)], the absorption peak of the H-aggregate [λmax = 495 nm (FIG. 4)
-B, Table 1-No. 7)] can be obtained. Furthermore, the addition of CdCl _{2 to} the lower layer (pure water) promotes the formation of H aggregates (FIG. 4-A, Tables 1-No. 4, No. 7).

[0007] Further, by setting the surface pressure to around 15 mN / m, H
Aggregates can be formed preferentially over the merocyanine type. When the temperature of the trough is 35 ° C., no H-aggregate is formed, which indicates that the temperature setting is also a major factor. Of the four factors described above, it is essential for the formation of H-aggregates to maintain UV irradiation and the temperature at a specific temperature during the compression process and the accumulation process during film formation.

[0008]

EXAMPLES Example 1 First, a literature [LD Taylor and RB Davis, J. Org.
em., 28 (1963) 1723], and 3-chloropiperidinium methyl-5-nitrosalicylic aldehyde was obtained as one of the starting materials by reaction with 3-chloromethyl-5-nitrosalicylic aldehyde and piperidine. . further,
Reference [DA Shiriey and WH Reedy ,. J. Am. Chem
Soc., 73 (1951) 458], and reacting stearyl tosylate with 1,3,3-trimethyl-2-methyleneindoline under reflux, alkali treatment with KOH, and extraction with ether. Dimethyl-1-octadecyl-2-
Methylene indoline was obtained as another starting material.

Then, the two are reacted under reflux, and the spiropyran compound SP18PI shown in FIG.
Cl [6-nitro-8-chloropiperidinium methylchromene-3-spiro-2 '-(3', 3'-dimethyl-
1'-octadecylindoline)]. Separation by column chromatography was performed to remove impurities, and the obtained photochromic component was again separated by column chromatography to obtain a SP18PICl sample.

FIG. 2 shows the absorption peak of SP18PICl in an acetone solution (λmax = 580 nm). SPl8PICl was dissolved in chloroform to prepare a developing solution (4.24 x 10 ^-4 M / 1). For the production of the LB film, a commercially available trough was used, and as the accumulation substrate, a non-fluorescent slide glass subjected to a hydrophobic treatment with trimethylchlorosilane was used.

The film forming method is a vertical Y-film method in which dipping is started from a gas phase. The number of layers was set to 20, the cumulative speed was set to 15 mm / min, the spread amount was set to 500 μl, and the surface pressure was set to 15 mN / m. After irradiation with ultraviolet rays for 20 minutes after the development, compression was performed. The half-life in Table 1 is at room temperature (25 ° C.).

For the merocyanine type, ultraviolet irradiation (3
Min) from the relationship between the decrease in absorbance at λmax and time, and from the relationship between the decrease in absorbance at λmax after film formation and time since the H aggregates are formed during film formation, It was calculated by the square method.

Table 1-No. Under the condition (1), a merocyanine-type absorption peak (λmax = 600 nm) as shown in FIG. 3-B was obtained by ultraviolet irradiation (3 minutes) after film formation, but it was unstable. In order to improve film forming property and structural stability, CdCl ₂ (1.1 × 10 ⁻⁴ ) is contained in the lower layer (pure water).
M / 1) was added. However, no H-aggregate was formed and there was no significant effect on improving the merocyanine-type stability (Table 1-No. 2). Under the same conditions, the surface pressure value is increased from 15 mN / m to 20 m
Although it was changed to N / m, no H-aggregate was formed and did not lead to stabilization of the merocyanine type (Table 1-No.
3).

Next, the irradiation of ultraviolet rays in the compression process and the accumulation process after the development during film formation, which is a feature of the present invention, is shown in Table 1-N.
o. When a film was formed under the conditions of No. 4, a peak having two absorptions (λmax = 600 nm, 500 nm) as shown in FIG. 4-B was obtained. The peak at 600 nm is a merocyanine-type absorption peak, and the peak at 500 nm is shifted to a shorter wavelength side than the absorption wavelength of the merocyanine-type in a polar solvent (acetone) (FIG. 2). Conceivable. Next, film formation was performed under the same conditions with the water temperature of the trough set to 35 ° C., but no absorption peak of the H-aggregate was obtained, and only the absorption peak of the merocyanine type as shown in FIG. Was obtained (Table 1-No. 5). Next, the water temperature of the trough was returned to 22 ° C., and CdCl ₂ (1.1 × 10 ⁻⁴ M / 1) was added again to improve the structural stability of the membrane, and ultraviolet rays were applied to the compression process and the accumulation process. To form a film (Table 1-No. 7).

As a result, a sharp absorption peak (λmax = 500 nm) of the H-aggregate was obtained (FIG. 3-A). On the other hand, when the surface pressure was changed from 15 mN / m to 20 mN / m under the same conditions,
A peak having two absorptions (λmax = 500 nm, 600 nm) as shown in FIG. B was obtained, and the ratio of the merocyanine type was increased (Table 1-No. 6).

[0016]

[Table 1]

Although SPl8PICl has been described above as an example, it can also be used for other spiropyran-based compounds (see "Photosensitive High Polymers", Nagamatsu and Inui, pages 82 to 83).

Example 2 Reference [LD Taylor and RBDavis, J. Org. Chem., 28 (196
3) 3-chloromethyl-5-nitrosalicylic aldehyde synthesized according to 1723] was obtained as one of the starting materials. Further, the literature [DAShiriey and WHReedy ,. J. Am. Chem So
c., 73 (1951) 458], and reacting stearyl tosylate with 1.3.3-trimethyl-2-methyleneindoline under reflux of benzene, alkali treatment with KOH, and extraction with ether to give 3,3. -Dimethyl-1-octadecyl-2-methyleneindoline was obtained as another starting material. Then, both are reacted under reflux, and the spiropyran compound SP shown in FIG.
18Cl [6-nitro-8-chloromethylchromene-3-spiro-2 '-(3', 3'-dimethyl-1'-octadecylindoline) was obtained, and separation by column chromatography was performed to remove impurities. The resulting photochromic component was again separated by column chromatography to obtain an SP18Cl sample, whose IR spectrum was shown in Fig. 6. Then, the chloroform solution containing SP18Cl was placed on the water surface in the same manner as in Example 1. Then, film formation was performed while irradiating ultraviolet rays during the compression and accumulation processes, and the results are shown in FIG.

As shown in FIG. 7A, even in the case of SP18Cl, a sharp H aggregate (λmax = 485 nm) similar to the absorption spectrum of the H aggregate (A) in FIG. 3 was obtained. This H-aggregate changes to a colorless spiropyran form with time, and the half-life of the H-aggregate at 25 ° C. in the dark is 60 mi.
n. When the spiropyran type is again irradiated with ultraviolet rays, the merocyanine type (λmax = 590 nm) shown in FIG.
Changed to The merocyanine form returned to the original spiropyran form in the dark, and its half-life was 15 min.

Example 3 In Example 2, the spiropyran compound SP1802 [6-nitro-8-methoxymethylchromene-3-spiro-2'-] shown in FIG. 8 was used by using ethanol instead of benzene as the reaction solvent. (3 ′, 3′-dimethyl-
1'-octadecylindoline)]. This SP1802
The NMR spectrum of is shown in FIG. The chloroform solution containing SP1802 was spread on the water surface in the same manner as in Example 1, irradiated with ultraviolet rays during the compression process, and accumulated on a glass substrate that had been hydrophobically treated with trimethylchlorosilane. As shown in FIG. 10A, a sharp H-aggregate (λmax = 495 nm) similar to the absorption spectrum of the H-aggregate of SP18PICl (FIG. 3, A) shown above was obtained. About 4 to 6 layers of stearic acid and arachidic acid as stearic acids, which are long-chain fatty acids, were accumulated on a hydrophobic glass substrate, and SP1802 was accumulated thereon. In this case, an aggregate (λmax = 575 nm) different from the H aggregate as shown in FIG. 10B was formed. FIG.
C is the absorption spectrum of photomerocyanine (λmax = 580 nm).

[0021]

According to the present invention, the stability of the spiropyran compound in the LB film is remarkably improved by the formation of the H-aggregate (for example, 15 times in comparison with the half-life). Further, the absorption peak is sharper than the merocyanine-type absorption peak, indicating the possibility of application to an optical recording medium by multiplex recording using a plurality of absorption wavelengths. Further, since the absorption wavelength shifts to the shorter wavelength side, application to an optical recording medium using an inexpensive light source such as a mercury lamp is also possible.

[Brief description of the drawings]

FIG. 1 is a view showing a chemical structural formula of a spiropyran compound SP18PIC1.

FIG. 2 is a graph showing a relationship between wavelength and absorbance in an acetone solution of SP18PICl.

FIG. 3 is a graph showing the relationship between the wavelength and the absorbance of the SP18PIC1 LB film for the merocyanine type (B) and H-aggregate (A).

Fig. 4 In the lower layer (water layer) of chloroform solution of SP18PICl
The relationship between the wavelength and the absorbance of the LB film formed with H-aggregate by adding CdCl ₂ was determined by measuring the surface pressure at 15 mN / m (A) and the surface pressure at 20 mN / m.
It is the graph shown about mN / m (B).

FIG. 5 is a view showing a chemical structural formula of a spiropyran compound SP18Cl.

FIG. 6 is an IR chart of a spiropyran compound SP18Cl.

FIG. 7 is a diagram corresponding to FIG. 3 for SP18Cl.

FIG. 8 is a view showing a chemical structural formula of a spiropyran compound SP1802.

FIG. 9 is an NMR chart of a spiropyran compound SP1802.

FIG. 10 is a diagram corresponding to FIG. 3 for SP1802.

Claims (1)

(57) [Claims] 1. A method for forming a molecular aggregate, comprising irradiating ultraviolet rays during the formation of a photochromic molecule by the LB method.