JPH03185090A - Photochromic material of heat stability type - Google Patents

Abstract

PURPOSE:To obtain the title material having both photochromic properties and durable heat stability, comprising a spiropyrane containing an intramolecular ion bondable substituent group as a constituent unit. CONSTITUTION:The objective material comprising a spiropyrane [preferable example; 1',3',3'-trimethylindolino-6-nitro-8(triethylammoniomethyl)- benzospiropyrane chloride] shown by the formula (X is cationic substituent group such as onium salt or carbocation or anionic substituent group such as oxy anion, enolate anion or carbanion) containing an intramolecular ion bondable substituent group as a constituent unit.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to photochromic compounds that exhibit reversible structural changes and accompanying color changes under light irradiation. The present invention relates to photochromic materials having the ability to retain thermally persistent color 11 due to electrostatic interactions between groups and isomerization sites.

(Prior Art) Photochromic materials are widely used as light amount adjusting materials, chemical photometers, decorative materials, optical recording materials, optical elements, etc.

Research has already been carried out to put it into practical use as a material for controlling the amount of light in sunglasses, goggles, dimming glasses, etc. In addition, high speed
Photochromic optical recording systems, which are expected to have recording characteristics with high density and multiplicity, are attracting attention, and attempts are being made to apply them to various photochromic compounds.

However, the prior art has many problems to be solved. In particular, the thermodynamic stability of each of the two isomers is important in that thermal reactions do not interfere with optical control;
Furthermore, a high degree of repeated durability is also required as a basic element of the material.

As photochromic compounds, fulgides, spiropyrans, spirooxazines, azobenzenes, thioindigos, diallyledenes, etc. are known. J (198
1 year〉], photochromic materials using these *
Many SCs are seen. Among these, fulgides [H.G. Heller EEE Proceedings, 130
Vol. 209 (1983)], diallyleketenes Masahiro Irie, Journal of Organic Chemistry Vol. 53, p. 803 (1988)], or photooxygenated aromatic polycyclic compounds [R. Schmidt, Journal・Op American Chemical Society Vol. 102, p. 2791 (1980)] is a compound with relatively excellent ripening stability of both photoisomers.

Compared to these, spiropyrans have a good photoresponse sensitivity, and a lot of research and development has been done on them, but on the other hand, their thermal stability is extremely low, and the color tone derived from the isomer cannot be sustained for a long time. Recently, there has been research on the production of compounds containing benzothiazoline, which has the disadvantage of not being able to be retained (Japanese Patent Application Laid-Open No. 58-37078) and the use of J-aggregate formation in LBI [Eiji Ando, "Nikkei New Materials", June 30th issue (1986)], or inclusion of amphiphilic compounds with bimolecular molecules or cyclodextrin. , supervised by Kunihiro Ichimura, "Applications of new photofunctional polymers," (1988)], and also, for example, P, 3'+
3'-trimethylindolino-6-nitro-8-methoxybenzospirobilane is known to form a chelate with steel (■) acetylacetonate in tetrahydrobilane in the presence of a trace amount of hydrochloric acid; The possibility of thermal stabilization has been shown [Shin Ohno, Journal of the Chemical Society of Japan,
Page 633 (1977)], however, methods that utilize intermolecular interactions with the medium surrounding photochromic compounds or with a second substance added to the system do not allow for the physical state of existence of these substances in the system. is extremely limited.

Therefore, there are almost no examples in which spiropyran is used as a component of a material.

Designing spiropyrans with both photochromic properties and sustained thermal stability would greatly expand their potential as materials, but no such strategy has been proposed.

(Problems to be Solved by the Invention) The present invention has been made with the object of providing spiropyrans that can be used as photochromic materials and have both photochromic properties and sustained thermal stability.

(Means for Solving Problem 11) The present inventors have conducted extensive research to achieve sustainable thermal stabilization of spiropyrans exhibiting photochromism.
In spiropyrans having an ion-bonding substituent (X) in the molecule, the ring-opening isomerization state (
Hereinafter referred to as the ring-opening type, the ring-opening type is thermally stabilized as a result of electrostatic interaction between the isomerization site and X, and the thermal stabilization is cut off in the excited state of the O ring-opening type It was discovered that spiropyran can be easily photoisomerized into the original spiropyran, and based on this knowledge, the present invention was completed.

That is, the present invention provides a photochromic material containing spiropyrans having an ionic bonding substituent X as a constituent element.

諌１□□usiieii, Aa.

The spiropyrans in the present invention include, for example, compounds whose partial structure is one of the 14 formulas shown below. The positions are not limited to those shown in the above formula, and other substituents R1
, R2, and R3, and may be located at any position within the molecule, such substituents X include those described below. That is, examples of cationic substituents include onium salts such as ammonium, aminium, iminium, pyridinium, oxonium, halonium, diazonium, acyllium, phosphonium, and sulfonium, and those containing units such as carbocations. Examples of anionic substituents include those containing units such as oxyanions, erlate anions, and carbanions such as sulfonic acids, sulfinic acids, sulfenic acids, carboxylic acids, thiocarboxylic acids, dithiocarboxylic acids, and alkoxides/ferulates. . In addition, β-
Examples include substituents containing complex ions such as diketone, ethylenediaminetetraacetic acid, and bipyridine. Spiropyrans having such a partial structure can be synthesized according to known methods.

Since the spiropyrans have an ionic r11m group, -r-wise, they can be mixed with water, alcohol, dimethylformamide,
It has high solubility in polar solvents such as dimethyl sulfoxide and acetonitrile.

Moreover, many of them are soluble in medium polar solvents such as acetone, tetrahydrofuran, dioxane, chloroform, methylene chloride, ethyl acetate, and diethyl ether. A thermosetting resin acid compound containing a structural unit represented by a pair of ionic substituents.

In the above formula, R, R2 and R1 are (X, Y are single bonds or 0.CL, C(CH,), C(CF,), C0
1S, SO2, which may be the same or different, each Z independently represents FlC(1,8
represents at least one of r, C, a lower alkyl group of ˜C1 or a 7-alkyl group, and each ring independently represents an integer of 0˜4. ) In the above formula, R1 is (X.

1 Z is the same as above. 1 is O~2, represents an integer from 0 to 3, and the crane represents an integer from 0 to 4.

〉 When the absorption band of spiropyrans (A) is excited with light of wavelength λ1, a heterolytic C-O cleavage reaction occurs, resulting in a ring-opened form with strong absorption in the visible region, but at this time, the ring-opened form is resonantly stable. structure (B1) and charge-separated structure (B2)
It takes two limit structures. In the spiropyrans in which the ion-binding W substituent X is present in the molecule, the open ring form is stabilized as a result of intramolecular ion pair formation between X and the isomerization site, as shown in the reaction formula. This results in inhibition of the mature reverse reaction that is normally seen in pond spiropyrans. On the other hand, when the visible absorption band of B2 is excited with light of wavelength λ2, the ion pairs are dissociated as the electrons are rearranged, and the reverse reaction to form the closed ring form (A) occurs quickly.

The spiropyrans can be easily dispersed in a polymeric matrix. Such polymers include polyethylene, polyvinyl chloride, polystyrene, polyvinyl alcohol, polyvinylacetic acid, polyvinylpyrrolidone,
Examples include, but are not limited to, polymethyl methacrylate, epoxy, polycarbonate, polyurethane, polyamide, polyimide, and copolymers thereof.

The thermodynamic stability of the ring-opened product is extremely high due to the electrostatic interaction between the isomerization site and the ionic binding Il substituent. That is, the decolorization speed of the open side body in the dark is very slow compared to non-exchangeable spiropyrans. Spiropyran, which has an ion-binding substituent triethylammoniomethyl group introduced at the 8-position, has 1800 times more thermal stability in methylene chloride (actual 31f?41) and 58 times more thermal stability in polymethyl methacrylate film. (Example 2)
.

(Effects of the Invention) The thermostable photochromic material of the present invention can be used in a wide range of applications such as optical recording materials, decorative materials, toys, display materials, and optical elements for repeatedly writing and erasing information using light or for long-term storage of information. It can be used for practical purposes.

(Example) Next, the present invention will be explained in more detail with reference to Examples.

Implementation fR1 1',3'39-trimethylindolino-6-nitro-
8-Chloromethylbenzospiropyran (synthesized by conventional method) 0. 5 g, ) 2 g of ethylamine was dissolved in 10 ml of acetonitrile and refluxed for 6 hours. The solid obtained by distilling off the melt under reduced pressure was washed with cyclohexane. After redissolving in the minimum amount of methylene chloride and adding 20 times the amount of cyclohexane, it was concentrated to 1/2 under reduced pressure. The obtained solid was filtered, washed with cyclohexane, and dried under reduced pressure to give 365 mg.
1',3',3'-trimethylindolino-6-nitro-8-(triethylammoniomethyl)-benzospiropyran chloride was obtained as a bright red solid.

This, 11,3#,3'=trimethylindolino-6-
Nit a'=A=:1-(triethylammoniomethyl)-benzospiropyran chloride O, O1 mmol
Immediately after preparation, the /l methylene chloride solution was a pale reddish-purple solution, but under room light it immediately became a colorless and transparent solution consisting only of closed bodies with no absorption in the visible region. When this was irradiated with ultraviolet light (365 nm or 254 nm), a reddish-purple solution having an absorption at 550 nm, which is characteristic of a closed ring, was obtained. This solution was extremely stable in the dark and the half-life of absorbance at 550 nm was approximately 20 hours at room temperature. P・3′ without ionic electrolyte group
- 3'-trimethylindolino-6-nitrobenzospiropyran has a half-life of about 40 seconds under the same conditions, and this spiropyran has 1800 times more thermal stability.

When this solution was irradiated with visible light of 440 nm, it immediately returned to its original closed ring form.

Example 2 P.3ζ3'-trimethylindolino-6-nitro-8-(triethylammoniomethyl) synthesized in Example 1
-0.0% benzospiropyran chloride. A chloroform solution containing 1% by weight of polymethyl methacrylate was placed on a glass plate and dried.

This film had a slight reddish-purple tinge when prepared, but immediately became colorless and transparent under room light. This is treated with ultraviolet light (365n
When irradiated with a wavelength of 254 nm or 254 nm, a reddish-purple film was obtained with an absorption at 550 nm, which is characteristic of a closed ring. This coloring is very stable in the dark and is 550n
The half-life of absorbance at m was approximately 116 hours at room temperature. It without ionic substituents, 31.
31-Trimethylindolino-6-nitrobenzospiropyran has a half-life of 2 hours under the same conditions, and the combined spiropyran has 58 times the thermal stability. When this film was irradiated with visible light of 440 nm, it immediately returned to a colorless closed ring form.

Claims (1)

[Claims] A photochromic material whose constituent elements are spiropyrans that have ionic bonding substituents in their molecules.