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Photochromic radical compounds based on a naphthopyran system
Takashi Kaneko1, Hiroki Akutsu, Jun-Ichi Yamada
1Department of Material Science, Graduate School of Science, Himeji Institute of Technology, 3-2-1 Kouto, Kamigori, Hyogo 678-1297, Japan.
Organic Letters
|June 7, 2003
Summary
Irreversible naphthopyran derivatives transform into open isomers upon irradiation. These compounds can be converted back to naphthopyrans using a silica catalyst, enabling tunable magnetic interactions.
Area of Science:
- Organic Chemistry
- Photochemistry
- Materials Science
Background:
- Naphthopyran derivatives are known for their photochromic properties.
- Controlling intermolecular magnetic interactions is crucial for developing advanced materials.
Purpose of the Study:
- To investigate the photoisomerization of naphthopyran derivatives with aminoxyl substituents.
- To explore the reversibility of the photochromic transformation.
- To assess the potential for tuning magnetic interactions in these systems.
Main Methods:
- Photochemical irradiation of naphthopyran derivatives (4a,b).
- Catalytic conversion of open-formed isomers (5a,b) back to closed-formed naphthopyrans using SiO(2).
- Analysis of intermolecular magnetic interactions.
Main Results:
- Naphthopyran derivatives (4a,b) with aminoxyl substituents yielded open-formed isomers (5a,b) upon irradiation.
- The open-formed isomers (5a,b) were successfully converted back to the original closed-formed naphthopyrans.
- Reversible photochromic behavior was observed.
- The study demonstrated the possibility of tuning intermolecular magnetic interactions in these reversible systems.
Conclusions:
- Reversible photochromism in naphthopyran derivatives with aminoxyl substituents was established.
- Silica (SiO(2)) acts as an effective catalyst for the ring-closure reaction.
- These systems offer a platform for developing switchable magnetic materials.
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