JPS63273687A - Photochromic material - Google Patents

Abstract

PURPOSE:To obtain a photochromic material being readily synthesized, formable into a thin film by LB method without damaging photochromic properties at all, comprising a specific fulgide having both a hydrophilic group and a hydrophobic group. CONSTITUTION:The aimed photochromic material comprising a fulgide shown by formula I {R is 5-31C (preferably 15-19C) alkyl], containing both a hydrophilic group and a hydrophobic group. A compound shown by formula II may be cited the example of the fulgide and is produced by processing ketofuran and a diester through a half ester to give a dicarboxylic acid, obtaining an acid anhydride of E from the dicarboxylic acid and reacting the acid anhydride with stearoyl chloride in the presence of tin chloride in a benzene solution.

Description

[Detailed description of the invention] Industrial applications The present invention relates to photochromic materials.

2. Description of the Related Art Photochromic materials have been known as materials that produce reversible color changes. Fulgide is one of the photochromic materials. (1) is the general formula of fulgide. In other words, fulgide is a compound in which an alkylidene group is attached to each of the two methylene carbons of an anhydrous acid or its derivative.

(However, at least one of R2 and R3 is an aromatic ring,
X=O, N-R) Many fulgides have been announced so far.Fulgide (2) is one of the fulgides with the most excellent photochromic properties. When irradiated with 337 nm ultraviolet light, the ring closes,
It changes to benzofuran form (3) and exhibits a red color. 473
When exposed to nm visible light, the process returns to (2) again.

(Left below) Using this property, research is being conducted to apply fulgide to optical storage media, photon detection devices, optical energy conversion devices, etc.

Problems to be Solved by the Invention With the miniaturization of electronic components, it is desirable to reduce the thickness of photochromic compounds when they are used in optical recording media, photon detection elements, and the like. In order to form an LB (Langmuir-Prodgett) film, which is a regular thin film of an organic compound, it is necessary to combine hydrophobic groups (e.g., hydrocarbon chains) and hydrophilic groups (e.g., carbonyl) in the molecule. (group) must be included. However,
Conventional fulgide (2) does not have a hydrophobic group, so LB
It was not possible to make the film thin using the method. Also, fulgide (2
) has often been difficult to synthesize.

This photochromic material, which has both functional hydrophilic groups and hydrophobic groups, is easy to synthesize and can be made into a thin film by the LB method without impairing the photochromic properties of fulgide.

EXAMPLE The chemical structural formula of an example of fulgide (hereinafter referred to as PIF-0) in the present invention is shown below.

The method for synthesizing FIF-0 is shown below.

(Step 1) To a benzene solution of 1 mol of 2.5-dimethylfuran and 1.5 mol of acetic anhydride was added at 0°C a benzene solution of 1 mol of anhydrous tin (IV) chloride over 1 hour. After several hours, ice (1.5 kg) and 5M hydrochloric acid (500 kg) were added.
ml). The aqueous layer was extracted with ethyl acetate, and the combined organic layers were washed with water and concentrated. Recrystallization from methanol yielded 0.8 mol of ketofuran.

(Step 2) Petroleum ether was added to 1 mol of sodium hydride and stirred for 5 minutes. After standing still and removing the supernatant, add acetone 1
．． A mixture of 5 moles and 1 mole of diethyl succinate anhydride was added. When one drop of ethanol was added thereto, the reaction started and hydrogen was violently generated. After hydrogen generation had subsided, diethyl ether was added and further stirred. After 1 hour, the reaction mixture was diluted with ethyl acetate and carefully extracted with an aqueous solution of IM sodium carbonate. 0.8 mol of Hafestel was obtained.

(Step 3) 0.8 mol of Hafestel obtained in Step 2 was dissolved in 500 ml of ethanol, 50 ml of concentrated sulfuric acid was added, and the mixture was heated to reflux. After 3 hours, the mixture was concentrated, and the residual odor was diluted with ether, which was washed with an aqueous sodium bicarbonate solution, dried, and concentrated again. The resulting residual aroma was separated by column chromatography to obtain 0.8 mol of diester.

(Left below) (Step 4) Add petroleum ether to 1.2 mol of sodium hydride and let it sit for 5 minutes. After leaving it to stand and removing the supernatant, add 0.8 mol of ketofuran obtained in step 1, The mixture of 0.8 mol of diester obtained in step 3 was dissolved in as little petroleum ether as possible and added. When one drop of ethanol was added thereto, the reaction started and hydrogen was violently evolved. After the hydrogen evolution stopped, Diethyl ether was added and stirring continued.After 1 hour, the reaction mixture was diluted with ethyl acetate.
After careful acidification by extraction with an aqueous solution of IM sodium carbonate, the organic layer was liberated.

It was extracted with ethyl acetate, dried over anhydrous magnesium sulfate, and concentrated. The obtained residual aroma was separated by column chromatography to obtain 0.5 mol of Hafestel.

(Step 5) After dissolving 0.5 mol of the obtained Hafestel in 5% alcoholic potassium hydroxide and heating under reflux for 15 hours,
The mixture was poured into 6N hydrochloric acid, extracted with ethyl acetate, dried over anhydrous sodium sulfate, and concentrated to obtain 0.3 mol of dicarboxylic acid. Further, 100 ml of acetyl chloride was added to 0.3 mol of this dicarboxylic acid, and the mixture was stirred at room temperature for 10 minutes. Thereafter, the reaction mixture was concentrated, and the residual aroma was separated and purified using silica gel column chromatography. The acid anhydride thus obtained was a mixture of the E form and two forms. This mixture was separated by recrystallization to obtain 0.05 mol of E-form acid anhydride exhibiting photochromism.

(Left below) (Step 6) 0.05 mol of E acid anhydride and 0.05 mol of stearoyl chloride
Add 0.1 mol of tin chloride benzene solution to 1 mol of benzene solution, stir at room temperature for 1 hour, and add ice (0.5 kg
) and 5M hydrochloric acid (100ml). The aqueous layer was extracted with ethyl acetate, the combined organic layers were washed with water, concentrated, roughly purified by column chromatography, and then recrystallized twice from methanol to obtain the desired fulgide F.
0.01 mol of IF-0 was obtained.

(Left below) Curve A in FIG. 1 shows the ultraviolet-visible absorption spectrum of a hexane solution of fulgide PIF-0 synthesized by the above method.

When this solution was irradiated with ultraviolet light of λ=280 nm, the ring was closed and colored yellow. This ultraviolet-visible absorption spectrum is shown as curve B in FIG. When it was further irradiated with visible light of λ=450 nm, the ring opened again and returned to a colorless form. Both the colorless and colored forms were very stable in the dark.

When this full-glide benzene solution was developed in a neutral phosphate buffer and accumulated on a silane-treated quartz substrate, a good LB film was obtained. 7 showed otochromism.

Note that fulgides with R of C=15 to 19 are the most desirable because they yield LB films of exactly the same quality. Although it is possible to form an LB film using fulgide with C=5, a good LB film could not be obtained with fulgide with C=4.

Further, although it is possible to form an LB film using fulgide with C=31, it is difficult to obtain acid chloride as a raw material for compounds with longer chains.

Effects of the Invention The present invention makes it possible to provide a photochromic material that forms an LB film, and its ripple effects are significant.

[Brief explanation of the drawing]

Figure 1 shows fulgide (FIF-0) used in Examples of the present invention.
) and its colored form in hexane. Patent applicant: Director of the Agency of Industrial Science and Technology Kozo Iizuka Figure 1

Claims (1)

[Claims] A photochromic material represented by the following general formula. (However, R is an alkyl chain with 5 to 31 carbon atoms) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼