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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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Photographs of single crystal 21a under polarized light before (a, θ = 0°; b, θ = 90°) and after (c, θ = 0°; d, θ = 90°) irradiation with UV light. θ is the rotation angle of the crystal. (e) crystal packing viewed from the (010) surface and the chemical structure of 21a.
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fig10: Photographs of single crystal 21a under polarized light before (a, θ = 0°; b, θ = 90°) and after (c, θ = 0°; d, θ = 90°) irradiation with UV light. θ is the rotation angle of the crystal. (e) crystal packing viewed from the (010) surface and the chemical structure of 21a.

Mentions: The multicolor change was also observed for a single-component crystal under polarized light.34) Figure 10a–d show the color change of single crystal (010) surface of 1,2-bis(2-methyl-6-nitro-1-benzothiophen-3-yl)perfluorocyclopentene (21a). Before photoirradiation the crystal was colorless (Fig. 10a and b). Upon irradiation with UV light, the crystal turned yellow at a certain angle (θ = 0). When the crystal was rotated as much as 90° (θ = 90), the color turned blue. The yellow color reappeared at 180°. The clear dichroism from yellow to blue is explained by the regular orientation of the diarylethene in the crystals. Figure 10e shows the chemical structure of 21b and the molecular packing of the diarylethenes viewed from (010) surface. The diarylethene has two electronic transitions, long and short axes, and the long and short axes transitions correspond to 600 nm and 465 nm absorption bands. When the polarized light coincides to the long axis, the crystal exhibits blue color (600 nm), while the color changes to yellow (465 nm) when the polarized light coincides to the short axis. Even single component diarylethene crystal can show two colors under polarized light.


Photochromism of diarylethene molecules and crystals.

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

Photographs of single crystal 21a under polarized light before (a, θ = 0°; b, θ = 90°) and after (c, θ = 0°; d, θ = 90°) irradiation with UV light. θ is the rotation angle of the crystal. (e) crystal packing viewed from the (010) surface and the chemical structure of 21a.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig10: Photographs of single crystal 21a under polarized light before (a, θ = 0°; b, θ = 90°) and after (c, θ = 0°; d, θ = 90°) irradiation with UV light. θ is the rotation angle of the crystal. (e) crystal packing viewed from the (010) surface and the chemical structure of 21a.
Mentions: The multicolor change was also observed for a single-component crystal under polarized light.34) Figure 10a–d show the color change of single crystal (010) surface of 1,2-bis(2-methyl-6-nitro-1-benzothiophen-3-yl)perfluorocyclopentene (21a). Before photoirradiation the crystal was colorless (Fig. 10a and b). Upon irradiation with UV light, the crystal turned yellow at a certain angle (θ = 0). When the crystal was rotated as much as 90° (θ = 90), the color turned blue. The yellow color reappeared at 180°. The clear dichroism from yellow to blue is explained by the regular orientation of the diarylethene in the crystals. Figure 10e shows the chemical structure of 21b and the molecular packing of the diarylethenes viewed from (010) surface. The diarylethene has two electronic transitions, long and short axes, and the long and short axes transitions correspond to 600 nm and 465 nm absorption bands. When the polarized light coincides to the long axis, the crystal exhibits blue color (600 nm), while the color changes to yellow (465 nm) when the polarized light coincides to the short axis. Even single component diarylethene crystal can show two colors under polarized light.

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