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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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Potential energy profile of the model system.
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fig05: Potential energy profile of the model system.

Mentions: To reveal the details of the photoisomerization reactions ab initio MO study was carried out for a model system.25–27) The energy profile of the potential surface is shown in Fig. 5 as a function of the internuclear distance (q) between two reactive carbons. The photocyclization reaction of the open-ring isomer proceeds as follows. Upon excitation from 1A to 1B state, the 1B state will relax to the minimum having C–C distance of 1.779 Å or crossover into 2A state and then relax to 2Ao. The 2Ao minimum is located between the closed- and the open-ring isomers. From this 2Ao point the system decays to the ground state open- or closed-ring isomers. The photocyclization reaction proceeds without any reaction barrier.


Photochromism of diarylethene molecules and crystals.

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

Potential energy profile of the model system.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig05: Potential energy profile of the model system.
Mentions: To reveal the details of the photoisomerization reactions ab initio MO study was carried out for a model system.25–27) The energy profile of the potential surface is shown in Fig. 5 as a function of the internuclear distance (q) between two reactive carbons. The photocyclization reaction of the open-ring isomer proceeds as follows. Upon excitation from 1A to 1B state, the 1B state will relax to the minimum having C–C distance of 1.779 Å or crossover into 2A state and then relax to 2Ao. The 2Ao minimum is located between the closed- and the open-ring isomers. From this 2Ao point the system decays to the ground state open- or closed-ring isomers. The photocyclization reaction proceeds without any reaction barrier.

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