JPH0559025A - Diarylethene compound - Google Patents

Abstract

PURPOSE:To provide a new diarylethene compound excellent in thermal stability and durability to repeated use, having good photochromic property and useful as an optically recording material. CONSTITUTION:A diarylethene compound of formula I (R is CH3, CF3), e.g. 1,2-bis(2-phenyl-4-trifluoromethylthiazolyl) hexafluorocyclopentene. The compound can be produced by reacting octafluorocyclopentene with 2-phenyl-4- trifluoromethyl thiazole or 4-methyl-2-phenylthiazole. The compound has a photochromic property and is changed into a yellow ring-closed compound of formula II on the absorption of UV rays. The compound of formula II is returned to the colorless ring-opened compound of formula I on the absorption of visible light. Both the compounds have high thermal stability, and are preserved in good states without change for a long period of time. The compounds have excellent durability against repeated coloration.decoloration processes and are thereby useful as reversible optically recording materials.

Description

Detailed Description of the Invention

[0001]

The present invention has the following formula (I):

[0002]

[Chemical 2]

(R is a methyl group or a trifluoromethyl group) and relates to a novel diarylethene compound. The above diarylethene compounds have photochromic properties and are useful as optical recording materials and the like.

[0004]

2. Description of the Related Art In recent years, reversible by light irradiation used for recording materials, memory materials, copying materials, light control materials, printing photoconductors, laser photoconductors, masking materials, photometers, display materials, etc. In particular, compounds having various photochromic properties that change the hue have been proposed.

For example, as these photochromic compounds, compounds such as benzospiropyrans, naphthoxazines, fulgides, diazo compounds and diarylethenes are known.

In order to apply such a photochromic compound to a reversible optical recording material, (1) storage stability of recording, (2) repetitive durability, (3) fast response speed,
Performances such as (4) semiconductor laser sensitivity, (5) nondestructive read-out function, (6) high sensitivity, and (7) compatibility with polymer medium are required.

However, the above existing photochromic compounds are generally thermally unstable in either a colored state or a decolored state, and return to a stable state within a few hours at room temperature. It has a drawback that stability cannot be secured.

[0008] Further, fulgides and diarylethenes are known to be relatively stable in terms of their two thermal states when exposed to light, but their storage stability is insufficient for use as an optical recording material. However, there is a drawback that the durability against repetition is poor, and there is no compound suitable for an optical recording medium, and an optical memory using a photochromic compound has not been realized.

[0009]

The inventors of the present invention have made earnest studies in view of such problems, and as a result, the following formula (I) is obtained.

[0010]

[Chemical 3]

It was found that the diarylethene compound represented by the formula (R is a methyl group or a trifluoromethyl group) is excellent in thermal stability and has a photochromic property with good repeated durability, thus completing the present invention. ..

That is, the present invention provides the following formula (I):

[0013]

[Chemical 4]

(R is a methyl group or a trifluoromethyl group) and is a diarylethene compound. The diarylethene compound represented by the formula (I) of the present invention can be produced, for example, by the following method.

That is, it can be produced by reacting octafluorocyclopentene with 2-phenyl-4-trifluoromethylthiazole or 4-methyl-2-phenylthiazole.

The reaction is octafluorocyclopentene 1
2-phenyl-4-trifluoromethylthiazole or 4-methyl-2-phenylthiazole is preferably used in an amount of 2 to 2.2 mol per mol, and it is carried out in the presence of n-butyllithium or the like. n-butyl lithium, etc.
It is preferable to use 2 to 4 mol, preferably 2.5 to 3 mol, per 1 mol of octafluorocyclopentene. Also,
The reaction temperature is preferably in the range of -70 to -50 ° C.
Further, it is preferable to use a solvent for the reaction, and tetrahydrofuran (THF) which is sufficiently dried is particularly preferable.

The diarylethene compound of the present invention has a photochromic property, and when it absorbs ultraviolet light as shown by the following formula, it changes to a closed ring and becomes yellow, and when this closed ring is irradiated with visible light, the original It returns to the ring-opened body of and disappears.

[0018]

[Chemical 5]

The ring-closed body in the colored state and the ring-opened body in the decolored state described above have high thermal stability and can be stored in a good state without change for a long period of time.
Further, the diarylethene compound of the present invention is excellent in repeated durability of coloring and decoloring, and is a compound useful as a reversible optical recording material.

[0020]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 1,2-bis (2-phenyl-4-trifluoromethyl)
Thiazolyl) hexafluorocyclopentene (the above formula
A compound in which R is a trifluoromethyl group in (I)
Product) (A) Production 2-phenyl-4-trifluoromethylthiazole 1 g
(4.36 mmol) was dissolved in 10 ml of dry THF, and 2.26 ml of n-butyllithium (2.0 mol-n-hexane solution) was added dropwise at -50 ° C in a dry ice acetone bath. After stirring at -50 ° C for 30 minutes, 0.49 g of octafluorocyclopentene (1.9
6 mmol) was added in small portions. After the addition was completed, the refrigerant bath was removed and stirring was carried out for 3 hours. 1 ml of water in the reaction solution
In addition, ether extraction was performed. After evaporating the solvent, the obtained solid was recrystallized from hexane-ethyl acetate to give 1,2-
Yellow plate crystals of bis (2-phenyl-4-trifluoromethylthiazolyl) hexafluorocyclopentene were obtained at a yield of 40%.

Melting point 155 to 156 ° C. IR (cm ^-1 , KBr) 3050 (Ph), 1200-1120 (CF ₃ , C)
F ₂ ) ¹⁹ F-NMR (δ from TFA, CDCl ₃ ) 14.36 (s, 6F), -35.00 (br-s, 4)
F) -54.70 (pent, 2F) Elemental analysis (%) Calculated value C: 47.63, H: 1.60, N: 4.44 Measured value C: 47.52, H: 1.85, N : 4.28 (B) Photoreaction Toluene solution of 1,2-bis (2-phenyl-4-trifluoromethylthiazolyl) hexafluorocyclopentene obtained in (A) (c = 1 × 10 ⁻⁵ mol) / L) was irradiated with a high-pressure mercury lamp (500 W) equipped with a UV-33S filter (Toshiba glass) for about 5 minutes to carry out a ring-closing reaction. The reaction liquid changed from colorless to yellow, and a change in the ultraviolet absorption spectrum was observed. The reaction liquid changed from that shown by the solid line to that shown by the dotted line. The ring-closed body easily returns to the ring-opened body due to sunlight, but it is 80
It was stable even after heating for a long time, was well retained as a ring-closed body, and did not decompose or ring-open at all.
After the lapse of 80 hours, the ultraviolet absorption spectrum when the closed ring was returned to the open ring completely returned from that shown by the dotted line in FIG. 1 to that shown by the solid line. Even at 130 ° C., only 15% decomposed or opened the ring in 30 hours. Example 2 1,2-bis (4-methyl-2-phenylthiazolyl)
Preparation of hexafluorocyclopentene (formula (I) above)
In which R is a methyl group) (A) Production 4-methyl-2-phenylthiazole 0.7 g (4.0
mmol) in 30 ml of dry THF and n-butyllithium 2.2 at -70 ° C in a dry ice acetone bath.
ml (2.0 mol-n-hexane solution) was added dropwise little by little. After stirring at -70 ° C for 30 minutes, 0.38 g (1.96 mmol) of octafluorocyclopentene was added little by little. After the addition is complete, remove the refrigerant bath and stir for 3
I went on time. Dilute hydrochloric acid was added to the reaction solution, and extraction was performed with ethyl acetate. After the solvent was distilled off, the obtained solid was produced by silica gel column chromatography (eluent: hexane / ethyl acetate = 50/1 (V / V)) to give 1,2-
Light yellow needle crystals of bis (4-methyl-2-phenylthiazolyl) hexafluorocyclopentene were obtained with a yield of 55%.

Melting point 106-108 ° C. IR (cm ⁻¹ , KBr) 3050 (Ph), 3000-2950 (CH ₃ ), 1
150-1120 (CF ₂ ) ¹⁹ F-NMR (δ from TFA, CDCl ₃ ) -32.70 (t, 4F), -54.46 (pent,
2F) Elemental analysis (%) Calculated value C: 57.46, H: 3.09, N: 5.36 Measured value C: 57.74, H: 3.26, N: 5.43 (B) Photoreaction A toluene solution of 1,2-bis (4-methyl-2-phenylthiazolyl) hexafluorocyclopentene obtained in (A) (c = 1 × 10 ⁻⁵ mol / L) was UV-33S.
High-pressure mercury lamp with filter (Toshiba glass) (500
The ring-closing reaction was carried out by irradiating with W) for about 5 minutes. The reaction liquid changed from colorless to yellow and a change in the ultraviolet absorption spectrum was observed. The ring-closed body easily returns to the ring-opened body by sunlight, but it is stable even when heated at 100 ° C. for 80 hours under light-shielding conditions, and is well retained as a ring-closed body, and none decomposes or opens the ring. It was .. Further, at 130 ° C., 80% decomposed or ring-opened in 30 hours.

[0023]

The diarylethene compound of the present invention is
It is a compound which is excellent in thermal stability, has good photochromic properties with good repeated durability, and is useful as an optical recording material.

[Brief description of drawings]

FIG. 1 is a diagram showing an optical change in an ultraviolet absorption spectrum of a compound prepared in Example 1 in a toluene solution.

Claims (1)

[Claims] 1. The following formula (I): (R is a methyl group or a trifluoromethyl group.) A diarylethene compound.