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Photochromism of diarylethene molecules and crystals.

Irie M - Proc. Jpn. Acad., Ser. B, Phys. Biol. Sci. (2010)

Bottom Line: The thermal irreversibility is an indispensable property for the application of photochromic molecules to optical memories and switches.We have developed a new class of photochromic molecules named "diarylethenes", which show the thermally irreversible photochromic reactivity.The well designed diarylethene derivatives provide outstanding photochromic performance: both isomers are thermally stable for more than 470,000 years, photoinduced coloration/decoloration can be repeated more than 10(5) cycles, the quantum yield of cyclization reaction is close to 1 (100%), and the response times of both coloration and decoloration are less than 10 ps.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Research Center for Smart Molecules, Rikkyo University, Tokyo, Japan.

ABSTRACT
Photochromism is defined as a reversible transformation of a chemical species between two isomers upon photoirradiation. Although vast numbers of photochromic molecules have been so far reported, photochromic molecules which exhibit thermally irreversible photochromic reactivity are limited to a few examples. The thermal irreversibility is an indispensable property for the application of photochromic molecules to optical memories and switches. We have developed a new class of photochromic molecules named "diarylethenes", which show the thermally irreversible photochromic reactivity. The well designed diarylethene derivatives provide outstanding photochromic performance: both isomers are thermally stable for more than 470,000 years, photoinduced coloration/decoloration can be repeated more than 10(5) cycles, the quantum yield of cyclization reaction is close to 1 (100%), and the response times of both coloration and decoloration are less than 10 ps. This review describes theoretical background of the photochromic reactions, color changes of the derivatives in solution as well as in the single crystalline phase, and application of the crystals to light-driven actuators.

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Typical color changes of several diarylethene derivatives in hexane solution upon photoirradiation.
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fig06: Typical color changes of several diarylethene derivatives in hexane solution upon photoirradiation.

Mentions: As noted in the introduction, photoinduced color changes are the most pronounced phenomenon observed in photochromic molecules. Figure 6 shows typical color changes of several diarylethene derivatives. When hexane solutions of the derivatives are irradiated with UV light, the colorless solutions turn to yellow, red, blue and green. The chemical structures of the derivatives, 15b–18b, are also shown in the figure. The color change is ascribed to the electronic structure change of the diarylethenes from the open- to the closed-ring isomers. The color is controlled by the length of π-conjugation of the closed-ring isomers. In 15b the π-conjugation is localized in the central part, while in 16b and 17b the π-conjugation delocalizes throughout the molecules and the length of 17b is longer than that of 16b. Therefore, the absorption maximum of 17b (blue) is longer than that of 16b (red). Nowadays, it is possible to estimate the colors using theoretical calculations.


Photochromism of diarylethene molecules and crystals.

Irie M - Proc. Jpn. Acad., Ser. B, Phys. Biol. Sci. (2010)

Typical color changes of several diarylethene derivatives in hexane solution upon photoirradiation.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3108296&req=5

fig06: Typical color changes of several diarylethene derivatives in hexane solution upon photoirradiation.
Mentions: As noted in the introduction, photoinduced color changes are the most pronounced phenomenon observed in photochromic molecules. Figure 6 shows typical color changes of several diarylethene derivatives. When hexane solutions of the derivatives are irradiated with UV light, the colorless solutions turn to yellow, red, blue and green. The chemical structures of the derivatives, 15b–18b, are also shown in the figure. The color change is ascribed to the electronic structure change of the diarylethenes from the open- to the closed-ring isomers. The color is controlled by the length of π-conjugation of the closed-ring isomers. In 15b the π-conjugation is localized in the central part, while in 16b and 17b the π-conjugation delocalizes throughout the molecules and the length of 17b is longer than that of 16b. Therefore, the absorption maximum of 17b (blue) is longer than that of 16b (red). Nowadays, it is possible to estimate the colors using theoretical calculations.

Bottom Line: The thermal irreversibility is an indispensable property for the application of photochromic molecules to optical memories and switches.We have developed a new class of photochromic molecules named "diarylethenes", which show the thermally irreversible photochromic reactivity.The well designed diarylethene derivatives provide outstanding photochromic performance: both isomers are thermally stable for more than 470,000 years, photoinduced coloration/decoloration can be repeated more than 10(5) cycles, the quantum yield of cyclization reaction is close to 1 (100%), and the response times of both coloration and decoloration are less than 10 ps.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Research Center for Smart Molecules, Rikkyo University, Tokyo, Japan.

ABSTRACT
Photochromism is defined as a reversible transformation of a chemical species between two isomers upon photoirradiation. Although vast numbers of photochromic molecules have been so far reported, photochromic molecules which exhibit thermally irreversible photochromic reactivity are limited to a few examples. The thermal irreversibility is an indispensable property for the application of photochromic molecules to optical memories and switches. We have developed a new class of photochromic molecules named "diarylethenes", which show the thermally irreversible photochromic reactivity. The well designed diarylethene derivatives provide outstanding photochromic performance: both isomers are thermally stable for more than 470,000 years, photoinduced coloration/decoloration can be repeated more than 10(5) cycles, the quantum yield of cyclization reaction is close to 1 (100%), and the response times of both coloration and decoloration are less than 10 ps. This review describes theoretical background of the photochromic reactions, color changes of the derivatives in solution as well as in the single crystalline phase, and application of the crystals to light-driven actuators.

Show MeSH
Related in: MedlinePlus