JPH0365840B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel photochromic material belonging to the spiropyran class.

Structure of the conventional example and its problems A photochromic substance is a substance that has the property (photochromism) of reversibly changing its chemical structure accompanied by a change in color when irradiated with light. Recently, attempts have been made to use the color change of photochromic materials for information storage. However, even if conventional photochromic materials undergo a color change, they fade and return to their original structure during short storage, so they have not been put to practical use for information storage purposes.

Object of the Invention An object of the present invention is to provide a photochromic material that does not fade due to long-term storage even after a color change occurs, and is a good material for an information storage medium. general formula It is expressed as

In the formula, R ₁ and R ₂ are −C _o H _2o+1 (n≧1), preferably R ₁ = R ₂ = −CH ₃ , and R ₃ is C _o H _2o+1 (n≧10), preferably 25≧n≧14, X is absent or −C _o H _2o OCO−, −C _o H _2o COO−, −C _o H _2o NHCO−, −C _o H _2o CONH− or −C _o
H _2o O-, (n≧O), preferably -CH ₂ OCO-,
−CH ₂ COO−, −CH ₂ CONH− or −CH ₂ NHCO
−, R ₄ is C _o H _2o+1 (n≧1, preferably n≧10)
It is.

The new spiropyran compound represented by the above formula is
It exhibits good photochromism with significantly less fading after color change, and by configuring the LB film,
Shows photochromic properties with less fading.

The most important point in the present invention is the length of the alkyl groups of R ₃ and R ₄ .

Spiropyran is generally treated by two types of light hν and hν′ with different wavelengths. A ring-opening-ring-closing reaction represented by: The reason why conventional spiropyran colored bodies fade quickly is because the ring-closing reaction occurs too easily. Focusing on this point, the present invention is characterized by achieving stabilization of the colored product by introducing long-chain alkyl groups into R ₃ and R ₄ to suppress the ring-closing reaction through steric hindrance.

Note that, in order to obtain such a suppressing effect to a practically sufficient degree, it is necessary that the number of carbon atoms in R ₃ and R ₄ is 10 or more.

Furthermore, the lengths of R ₃ and R ₄ are also important factors when constructing the LB film. The characteristics that make up the LB film are:
It is correlated to the length of R ₃ and R ₄ respectively. As a result of considering the lengths of R ₃ and R ₄ , the inventors found that R ₃ is a substance with 10 or more carbon atoms (preferably 14 to 25), and R ₄ is a substance with 1 or more carbon atoms (preferably 10 or more). is a good LB
We found that it is possible to construct a membrane, and that the stability of the substance itself and the stabilization achieved by constructing the LB membrane can be achieved.

Description of Examples Hereinafter, as a first example, a typical method for synthesizing the compounds described above will be shown.

(a) After refluxing 0.5 mol of 2,3,3-trimethylindolenine and 0.5 mol of iodooctadecane (C ₁₈ H ₃₇ I) in chloroform for 3 hours,
Washing with diethyl ether gave a red solid (1-octadecyl-2,3,3.trimethylindolenium iodide).

After treating this with a concentrated KOH aqueous solution, extracting with diethyl ether and drying, the red liquid (1
-octadecyl-3,3'-dimethyl-2-methyleneindoline) was obtained.

(b) 0.5 mol of 5-nitrosalicylaldehyde was dissolved in 1 mol of chloromethyl methyl ether, 2.5 mol of ground aluminum chloride was added while cooling on ice, and after refluxing for 80 hours, ice was added to the solution. A brown precipitate was deposited in the melted ice, and when this was recrystallized using n-hexane 10, needle-like colorless crystals (3-chloromethyl-5-
nitrosalicylaldehyde) was obtained.

(c) Mix 0.1 mol of 3-chloromethyl-5-nitrosalicylaldehyde synthesized in (b) with 0.15 mol of silver stearate (C ₁₇ H ₃₅ COOAg), reflux in toluene for 40 hours, and then prepare a hot solution. was filtered, and the three liquids were cooled to obtain white crystals (3-stearoyloxymethyl-5-nitrosalicylaldehyde).

(d) 1-octadecyl synthesized in (a) and (b) respectively
0.05 mol each of 3,3'-dimethyl-2-methyleneindoline and 3-stearoyloxymethyl-5-nitrosalicylaldehyde,
After refluxing for 20 hours in methyl ethyl Kent, the product was purified on a column (supported silica gel, solvent was CCl ₄ /CHCl ₃ = 10/3). A spiropyran with the structure was obtained.

In order to examine the effects of the present invention, we used the known spiropyran (SP ₁ ), which is considered to be the most representative, and is represented by the following formula. A comparative test of fading life was conducted using .

Both types of spiropyran were 1×10 ^-3 mol/
When irradiated with ultraviolet rays having a wavelength of 250 to 350 nm for 15 minutes, the product of the present invention was colored blue, and SP ₁ was colored reddish-purple. Using the absorbance at this point as a standard, the time required for the absorbance to decrease by half after storing it in a dark room was measured, and it was 5 hours for SP ₁ and over 100 hours for the substance of the present invention.

Next, a second embodiment will be explained.

5×10 ^-3 mol/of spiropyran in the first example
1×10 ⁻⁴ ml of benzene solution was dropped onto a clean water surface with an area of 800 cm ² . The benzene solution expanded to form a monolayer of spiropyran at the air-water interface. While measuring the surface pressure (π) of the spiropyran monolayer, the monolayer was compressed by sweeping the water surface with a water-repellent bar. The relationship between the occupied surface per molecule (A ² /molecule) and the surface pressure (dyne/cm) in this operation is illustrated. The figure suggests that the spiropyran of the present invention forms a good monolayer.
While maintaining the surface pressure of the spiropyran monomolecular film at 20 dyne/cm, a quartz glass plate whose surface had been made hydrophobic with trimethylchlorosilane was vertically immersed in water and pulled out. It moved from the water interface to the quartz plate surface. By repeating this operation 10 times, a cumulative monomolecular film with a total of 40 layers on the front and back sides was formed on the quartz plate. Using this monomolecular cumulative film, we conducted a comparison experiment on fading life similar to the first example, and found that
Achieved a long service life of over 1000 hours. We also tried forming a monolayer using SP ₁ in a similar manner, but
SP ₁ did not form any monolayer.

Effects of the Invention According to the present invention, a photochromic dye with an extremely long fading life is realized.

[Brief explanation of drawings]

The figure is a graph showing the relationship between the surface pressure of spiropyran and the molecular occupied area in an example of the photochromic material of the present invention.

Claims (1)

[Scope of Claims] 1. A photochromic material comprising a compound represented by the following general formula. Here, R ₁ and R ₂ are alkyl groups represented by -C _o H _2o+1 (n≧1), R ₃ is -C _o H _2o+1 (n≧10),
X does not exist or -C _o H _2o OCO-, -C _o
H _2o COO−, −C _o H _2o NHCO−, −C _o H _2o CONH
-, or -C _o H _2o O- (n≧0 in either case), and R ₄ represents C _o H _2o , (n≧10) (n is an integer in all cases). 2. A photochromic coating consisting of a monomolecular cumulative film of a photochromic material consisting of a compound represented by the following general formula. Here, R ₁ and R ₂ are alkyl groups represented by -C _o H _2o+1 (n≧1), R ₃ is -C _o H _2o+1 (n≧10),
X does not exist or -C _o H _2o OCO-, -C _o
H _2o COO−, −C _o H _2o NHCO−, −C _o H _2o CONH
-, or -C _o H _2o O- (n≧0 in either case), and R ₄ represents C _o H _2o (n≧10) (n is an integer in all cases).